The abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (Fundulus heteroclitus)

The abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (Fundulus heteroclitus) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish ( Fundulus heteroclitus ) Jordan A. Pitt, Scott M. Gallager, Sarah Youngs, Anna P. M. Michel, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4916090/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Nov, 2024 Read the published version in Microplastics and Nanoplastics → Version 1 posted 9 You are reading this latest preprint version Abstract Microplastics (MPs) have been found in a diverse range of organisms across trophic levels. While a majority of the information on organismal exposure to plastics in the environment comes from gastrointestinal (GI) data, the prevalence of MP particles in other tissues is not well understood. Additionally, many studies have not been able to detect the smallest, most prevalent, MPs (1 µm – 5mm) that are the most likely to distribute to tissues in the body. To address these knowledge gaps, MPs in the GI tract and muscle of Atlantic killifish ( Fundulus heteroclitus ) collected from two sites on Buzzards Bay, Cape Cod, MA were quantified down to 2 µm in size. Fourier-transform infrared spectroscopy and Raman spectroscopy were used to identify all particles. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4 % (69 particles) were identified as plastic; polymers included nylon, polyethylene, polypropylene, and polyurethane. MP abundance in the GI tract was greater than in the muscle. MPs detected in the GI tract samples also tended to be more diverse in both size and polymer type than those found in the muscle. We found that MPs <50 µm, which are often not analyzed in the literature, were the most common in both the GI tract and muscle samples. There was not a significant correlation between the MP content in the muscle compared to the GI tract, indicating that GI tract MP abundance cannot be used to predict non-GI tract tissue MP content; however, MP abundance in muscle correlated with fish total length, suggesting potential bioaccumulation of these small MPs. microplastics fish translocation Fourier-transform infrared spectroscopy Raman spectroscopy bioaccumulation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Understanding the fate of plastics in the ocean is challenging, in part, because plastics are an incredibly diverse suite of contaminants (Rochman et al., 2019a ). The size, surface chemistry, polymer type, state of degradation, and additives present can all influence the distribution and fate of microplastics (1 µm < particle < 5 mm; MPs) in the environment (Rochman et al., 2019b ). The exact influence of these factors on particle abundance and distribution in the environment is still poorly understood due to analytical limitations and a lack of harmonized methods (Koelmans et al., 2019 ). Plastic ingestion is widespread, having been documented in more than 1,565 aquatic and terrestrial species (Santos et al., 2021 ). Even though ingestion is well-documented, the bioaccumulation potential of microplastics is not well understood. Bioaccumulation is classically defined as the buildup of a material in an organism over its lifetime (Nordberg, 2009 ; Suedel et al., 1994 ); however, the movement of MPs is likely to be more constrained due to their large particulate nature. The ultimate fate of these ingested MPs is both complex and unknown. One of the key challenges is that small MPs (smaller than 50 µm), the most prevalent size of environmental plastics (Lebreton et al., 2019 ), are difficult to find and identify in environmental samples (Lebreton et al., 2019 ). Smaller particles can often be misidentified as MPs due to a lack of distinguishing characteristics as the particles decrease in size (Lenz et al., 2015 ; Remy et al., 2015 ). The abundance of MPs is expected to increase with decreasing size, but there is little information regarding the movement and fate of particles smaller than 50 µm in aquatic environments (Enders et al., 2015 ; Erni-Cassola et al., 2017 ). In addition to being more abundant in the environment, smaller MPs are also more likely to translocate from the gastrointestinal (GI) tract into internal tissues (Lusher et al., 2017 ). Therefore, having an accurate size distribution of ingested MPs is critical to understanding exposure and, ultimately, the risk that MPs pose to marine animals. There is still much to discover regarding the characteristics of particles that govern MP translocation into non-GI tract tissues since the majority of published data examines plastic exclusively in the GI tract (Gouin, 2020 ; Pitt et al., 2024 ). Without this information, the implications of ingestion for bioaccumulation, trophic transfer, and biomagnification of MPs cannot be predicted (Provencher et al., 2019 ). Current research suggests that bioaccumulation of MPs is unlikely, but this prediction is limited to particles larger than 100 µm, emphasizing the need for research on the accumulation of smaller MPs in tissues (Covernton et al., 2022 ). Smaller MPs are often not quantified in tissues due to analytical challenges (Hermsen et al., 2018 ; Provencher et al., 2019 ) and high levels of background contamination (Hermsen et al., 2018 ; Löder et al., 2017 ). The objective of this study was to quantify the full-size range of MPs using strict quality control procedures to reduce background contamination. Through this approach, we aimed to distinguish differences in characteristics of MPs detected in the GI tract and muscle of Atlantic killifish ( Fundulus heteroclitus ) and address the bioaccumulation potential of the under-reported small MPs. 2. Materials and Methods 2.1 Materials Pyrex glassware was used whenever possible during this study. Whatman (grade 4; 25 μm pore size) and nitrocellulose (pore size of 1 μm) filter papers (Sigma Aldrich) were used for Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy analysis. Minnow traps were used for collecting Atlantic killifish. 2.2 Quality Control We followed the quality control criteria established by Hermsen et al. (2018). All water samples and solutions were filtered through a 0.2 μm filter prior to use. All sample processing apparatus (glass Erlenmeyer flasks and ceramic Buchner funnels) were combusted in a muffle furnace (Fisher Scientific Isotemp Programmable Forced-Draft Furnace) at 500 ℃ for 5 h. Glassware that could not be combusted in the furnace was rinsed three times with both acetone and filtered water prior to use. All work surfaces were wiped down with ethanol prior to working with samples. Sample manipulation took place in a laminar flow hood (AirClean 600 PCR Workstation). Samples were not exposed to ambient air. When the samples were not being actively manipulated, they were covered with aluminum foil. While working with samples, a 100% cotton jumpsuit was worn to prevent contamination from polyester clothing. During sample processing, occupancy of the room was kept to a single person. Procedural blanks were used for every 5 samples. 2.3 Fish collection and tissue sampling Atlantic killifish were collected using minnow traps from two locations in Buzzards Bay, Massachusetts (Fig. 1). The sampling dates, coordinates, number of fish collected, and the environmental conditions are shown in Table S1. Fish were immediately euthanized using MS222 (1 g/L) buffered with sodium bicarbonate. Fish were kept in an aluminum-foil lined bucket during transport. The total length and weight, sex, and tissue wet weights were recorded upon collection. Prior to dissection, fish were rinsed three times with 0.2 μm filtered water to remove any loose particles on the fish’s skin. The GI tract and a section of the dorsal muscle (without skin) were collected. The total GI tract, including contents, were used in our analysis. Tissues were stored in plastic-free aluminum foil at -80 °C. All collected fish were considered mature as they exceeded 3.2 cm or 3.8 cm for males and females, respectively, and they were in good overall health according to the calculated condition factors (Abraham, 1985). Based on length-age relationships (Abraham, 1985), the collected fish from Bourne, MA appear to be a couple of years younger than the collected fish from Falmouth, MA. At both sampling sites, we collected water samples in 1 liter glass jars. The jars were rinsed three times in water from the collection site prior to sample collection. To prevent air contamination, the jars were immersed underwater prior to opening. Duplicate water samples were collected from each site. Samples were stored at room temperature (20 - 25 ℃). 2.4 Sample Digestion A flow chart of the sample processing and analysis is shown in Figure 2. Tissue samples were digested with 10% KOH (3x sample wet weight) at 60 ℃ for 48 h (Fig. 2). KOH digestion at this temperature has previously been shown to not degrade MPs (Gulizia et al., 2022). Digests were neutralized with a combination of sodium bicarbonate (0.05 g/mL) and 10% HCl (0.54 mL HCl/mL KOH) prior to filtration. Particles in the samples were size fractionated by filtering initially through a 25 μm pore-size filter followed by a 1 μm filter (Fig. 2). Filters were stored in plastic-free aluminum tins until analysis. The 25 μm pore-size filter was used for FTIR spectroscopy analysis and the 1 μm filter was used for Raman spectroscopy (Fig. 2). Size fractionation was used to analyze samples more efficiently. Raman spectroscopy is more accurate at identifying particles smaller than 20 μm in length, and FTIR is a more efficient method for particles >20 μm in length (De Frond et al., 2023). 2.5 Particle Recovery experiments Particle recovery experiments were conducted using polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyethylene (PE) particles (250 μm) dyed with 300 μL of Nile Red (10 μg/mL). Blue mussel ( Mytilus edulis ) tissue was used to determine the particle recovery from the MP isolation process from biological tissues. Fifty particles from each polymer type were manually added to whole mussel tissue ( Mytilus edulis) in Erlenmeyer flasks. The mussels were then digested for 48 h as in section 2.4. The resulting digests were then filtered through 25 μm pore-size filters. Each flask was washed three times with filtered water. The number of particles on the filter were counted under a dissecting microscope. There was 80% recovery of particles regardless of the polymer type (n=2 experiments per polymer) (Fig. S1). 2.6. FTIR spectroscopy Sample Analysis The 25 μm filters were scanned for particles under a dissecting microscope at 8.6x magnification. The whole filter was examined, and any particles found were imaged (ThorCam Imaging Software V.3.5.1.1). Particles were then transferred to a piece of double-sided tape in a glass petri dish and numbered. These particles were analyzed with a diamond attenuated total reflection (ATR) attachment on the Cary 630 FTIR (Agilent Technologies Inc). Particles were placed individually on the detection area. MicroLabPC software was used to collect the spectra. 2.7. Raman spectroscopy Sample Analysis The 1 μm filter was used for Raman analysis. The particles were analyzed with a Renishaw inVia Raman microscope using Wire 3.4 software to collect images and spectra of the particles. Spectra were collected with a 532 nm excitation laser. The filter was scanned at 20x magnification. Eight transects were made in a straight line across the filter covering 8% of the filter (Fig. 2). Particles were imaged prior to spectra collection. If particles were smaller or larger than the 20x field of view, 50x or 5x magnification was used to image the particle. 2.8. Data Validation and Analysis The collected spectra from FTIR and Raman spectroscopy were baseline corrected and smoothed prior to identification. OpenSpecy (Cowger et al., 2021) and a custom library database were used for identifying the particles based on their spectra. Pearson’s correlation coefficient (Pearson’s r) of greater than or equal to 0.8 was used as a statistical cutoff for a good fit between the reference and the particle spectrum (Giani et al., 2023; Zhu et al., 2023). All the plastic particle spectra (Pearson’s r > 0.8) were then manually checked to ensure that the spectral peaks were well matched with the reference peaks from both the libraries (Renner et al., 2019). Particles (Pearson’s r > 0.8) were not used in the subsequent analysis if they had peaks that either did not match the overall pattern in the reference spectrum or had a low enough signal-to-noise ratio that it was challenging to interpret the true signal. Examples of spectra that were included or excluded in the analysis are shown in Figure 3, Spectral peaks were identified according to commonly reported Raman shifts in the literature. Plastic degradation or weathering peaks were identified in all of the samples. Non-plastic particles were compared to reference spectra for a variety of different materials, including fur, cellulose, cotton, sand, chitin, and plant material. The non-plastic particles were identified by a Pearson’s r of 0.8 or greater without manually comparing the spectra matches. 2.9. Statistics Fulton’s condition index (K) (Equation 1) was calculated to determine the overall health of the fish (Ricker, 1975). Equation 1: K=(W/TL 3 )* 100; W is the fish weight and TL is the total length. MP abundance and occurrence data were non-normally distributed, so nonparametric analyses were used. To predict the occurrence of MPs in the muscle, a Random Forest model was generated using the R CARET package’s leave-one-subject-out train() function (Kuhn, 2008). Fish length, sex and plastic content in the GI tract were used as input variables. Spearman’s rank correlation was used to determine the correlation between fish total length and GI tract and muscle MP abundance. Graphpad Prism (10.0.2) was used to calculate the Spearman’s rank correlations and to generate the visualizations. Significant correlations were accepted if the p-value of the Spearman’s rank correlation was less than 0.05. The Random Forest analysis used MP occurrence in muscle samples, and the Spearman’s rank correlation used the muscle MP abundance. All concentrations are reported as the number of particles per gram of tissue wet weight. Data from the Raman analysis are based on the whole filter plastic count estimates extrapolated from the 8% of the filter that was analyzed. No corrections were made for the FTIR data since the whole filter was analyzed. 3. Results In the eighteen fish analyzed, 69 MPs were identified in the GI tract or the muscle. The fish collected from Falmouth generally contained more MPs than the fish collected from Bourne. Given the developing nature of the field, we describe the different metrics used to verify our sample analysis below. In the next section, the differences in MP morphologies are compared between the GI tract and muscle samples. Following that, we examine the impact of fish total length and sex on MP abundance. 3. 1. Methodology Verification All encountered particles were analyzed using either Raman or FTIR. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4% (69 particles) were identified as plastic (Table S2). All particles identified as plastic had a Pearson’s r correlation of at least 0.82, and an average correlation of 0.91 (Table S3). In Falmouth fish, there were 50 plastic particles in the GI tract samples and nine in the muscle tissue. The Bourne fish had nine plastic particles in the GI tract and only one in the muscle tissue. In our procedural blanks, only one particle was identified as plastic (polypropylene). No polypropylene was detected in the fish samples analyzed concurrently with the contaminated procedural blank. Due to the detection of only a single plastic particle out of 11 procedural blanks, no blank correction was performed. Of the 180 particles analyzed with a correlation of at least 0.8, 70 particles were included in the microplastic analysis. Particles not included could be plastic particles that had altered spectra due to particle oxidation or the presence of additives. The analysis we used is highly conservative, due to uncertainty surrounding the 110 particles not included in the analysis. Numerous plant-based, chitin and or bone particles were detected with FTIR analysis (Fig. S2A & S2B). Fish collected from Bourne had more plant-based particles in their GI tracts than Falmouth fish (Fig. S2A). Some cellulose and cotton particles were also detected in the samples (Fig. S2). Raman spectroscopy analysis detected primarily minerals, metal compounds, and fragments of soot or black pigment (Fig. S2C & S2D). 3.2. Plastic particle identification 3.2.1. Plastic Concentrations MP occurrence varied widely between the water and fish tissue (GI tract and muscle) samples. The water samples had no detected MPs (Fig. 4 A). GI tract samples contained MPs more frequently than the muscle samples (Fig. 4 A). Most Falmouth fish contained MPs, with 87.5% of the GI tract samples and 62.5% of muscle samples containing MPs (Fig. 4 A). The Bourne sampling site had a lower MP occurrence, with 40.0% of the GI tract samples and 10.0% of muscle samples containing MPs (Fig. 4 A). MP concentration varied by tissue and sampling site, with the Falmouth GI tract samples containing the largest concentration of plastics (Fig. 4 B). The median concentration of MPs in the GI tract of fish from Falmouth was 83 particles/g w.w. while the muscle samples had a median concentration of only 11 particles/g w.w. tissue. Both the GI tract and muscle samples from Bourne fish had a median concentration of 0 particles/g w.w. with the GI tract having a 2.6x greater range compared to the muscle samples (Fig. 4 B). Many fish did not contain any MPs (Table 1 ), leading to large standard deviations. 3.2.2. Plastic Sizes Table 1 Average Concentration and Size of MPs in fish tissues from Falmouth and Bourne. The mean concentration ± 1 standard deviation is shown. For size characteristics, the medians are shown with range in parentheses. Collection Site Falmouth Bourne Tissue GI Tract Muscle GI Tract Muscle MP Occurrence (# MP samples/total sample number) 7/8 5/8 4/10 1/10 MP Concentration (Particle Count/g w.w.) 85.5 ± 70.2 11.4 ± 12.5 12.2 ± 18.1 1.69 ± 5.36 Length (µm) 24.8 (2.60–1291) 15.5 (4.26–28.1) 24.6 (5.19–728) 8.73 Width (µm) 12.6 (2.10–140) 9.52 (1.79–13.8) 13.8 (2.35–248) 8.95 Aspect Ratio (Length/Width) 1.41 (0.61–51.0) 2.13 (0.97–10.8) 2.21 (1.28–6.78) 0.98 The MP size distributions were similar between the two collection sites (Table 1 ), so the data from the sampling sites were combined to more closely examine how MP characteristics differ between tissues. Particles 2 µm − 5 mm in length were analyzed in the collected samples. Length is defined as the longest dimension of the particle in a 2-dimensional plane. The particle lengths ranged from 2.6 µm − 1291 µm. The median MP length in the GI tract was 24.7 µm, and the median MP length for the muscle samples was 14.5 µm (Fig. 5 A). MPs in the GI tract had a greater size range of 1289 µm compared to the muscle MP’s size range of 23.9 µm (Fig. 5 A); however, for both tissue types most of the particles (81.2%) were smaller than 50 µm in length (Fig. 5 A). 3.2.3. Plastic Shape The particle aspect ratio was determined by dividing the length of the particle by the particle width. The particle aspect ratios varied more widely in the GI tract than in the muscle samples (Fig. 5 B). The median aspect ratios for the GI tract and muscle were approximately 1.6 and 1.9, respectively (Fig. 5 B). An aspect ratio of three or greater was used to define a particle as a fiber (Li et al., 2020 ). Any particles with an aspect ratio below three were defined as a fragment. The identified MPs were predominantly fragments (Fig. 5 C). The GI tract and muscle samples had similar percentages of fragments and fibers. The GI tract particles were 78.6% fragments and 21.4% fibers, and the muscle particles were 80.0% fragments and 20.0% fibers (Fig. 5 C). 3.2.4. Polymer Types Nylon was the major polymer present in the samples (Fig. 6 ). Polyethylene was found in the GI tracts collected from both Falmouth and Bourne sites in roughly equivalent percentages (Fig. 6 A). We rarely found polypropylene and polyurethane in the samples (Fig. 6 A). The GI tract particle composition consisted of nylon (84.8%), polyethylene (11.9%), polypropylene (1.7%), and polyurethane (1.7%) (Fig. 6 B). The MPs found in the muscle samples were all nylon (Fig. 6 B). The full range of both the length and aspect ratio for each particle is shown in Figure S3A. The length of the nylon particles was significantly correlated (r = 0.5; p-value < 0.001) with aspect ratio (Fig. S3A & S3B; Linear regression R 2 = 0.74). The length of the polyethylene particles, on the other hand, was not correlated with the aspect ratio (r = 0.42; p-value 0.35; Fig. S3B). The polyethylene particles and nylon particles had similar proportions of fragments (Fig. S3C). 3.2.5. Plastic Weathering Identified MPs frequently had two spectral peaks (800–900 and 1600–1700 cm − 1 ) suggestive of particle oxidation (Fig. S4; Matsui et al., 2000 ; Phan et al., 2022 ). An example of a spectrum displaying these oxidation peaks is illustrated in Figure S4A & S4B along with a picture of the particle and its identified chemical structure. Many particles found in both the GI tract and the muscle samples contained both of those peaks, indicating oxidation of the particles (Fig. S4C). Fewer MPs had the additional 1600 cm − 1 peak compared to the 800–900 cm − 1 peak (Fig. S4C). It should also be noted that only 10 MPs were detected in the muscle samples, which could skew the reported peak proportions. 3.3. Impact of Fish Length on Microplastic Abundance MP abundance correlated with fish total length in the muscle and GI tract; however, key differences between the fish from the different sampling sites complicated this analysis. Only female fish were caught at the Falmouth site (8/8 fish), and mostly male fish were caught at the Bourne site (8/10 fish). The fish collected at the Falmouth site were also larger than those collected at the Bourne site (Fig. 7 ). These site differences made it challenging to disentangle the impact of sex and fish total length from the different collection sites (Fig. 7 ). Fish collected from both sites had equivalent Fulton’s condition factors. Additionally, the water samples from both sites had MPs below the limit of detection, indicating that MP prevalence is low at both collection sites. Therefore, for the following analyses the information from both collection sites has been combined. Fish total length correlated with MP abundance in both the GI tract (r = 0.51; p-value 0.03) and the muscle (r = 0.48; p-value 0.04; Fig. 8 A & 8 B). Both comparisons showed a moderately positive relationship. GI tract MP abundance did not correlate with muscle MP abundance (r = 0.25; p-value 0.31; Fig. 8 C). Female fish had a greater MP abundance than male fish in both the GI tract and muscle (Fig. 8 D). In fact, only female fish had MPs present in the muscle (Fig. 8 D). The random forest analysis determined that fish total length was the most important variable for predicting muscle MP occurrence, followed by fish sex and then GI tract MP abundance (Table S4). 4. Discussion The bioaccumulation potential of environmental MPs is not well understood, in part because MP detection is a developing field with little harmonization amongst methods. This study sought to draw on existing recommendations from the field while expanding on both classification techniques and the detectable size range of MPs. Using this rigorous approach, we compare the characteristics of MPs found in the GI tract and muscle. Of particular focus in the following sections are the small size of detected MPs and the correlation of MP abundance and fish total length. Other factors are also discussed to ensure a thorough characterization of the data for future research to draw upon. 4.1. Importance of Methods in MP Assessment The concentrations and occurrence frequencies of MPs from different field studies are difficult to compare due to the lack of standardized methods across the field. It is unclear how much differences in MP identification approaches (Abbasi et al., 2018 ; Akhbarizadeh et al., 2018 ; Curtean-Bănăduc et al., 2023 ; My et al., 2023 ; Piskuła & Astel, 2023 ; Qaiser et al., 2023 ), collection methods (Guilhermino et al., 2021 ; Matupang et al., 2023 ; Menéndez et al., 2023 ; Piskuła & Astel, 2023 ; Sultan et al., 2023 ), and quality control measures (Esmaeilbeigi et al., 2023 ; Kumari et al., 2023 ; Nawar et al., 2023 ; Piskuła & Astel, 2023 ; Qaiser et al., 2023 ; Raza et al., 2023 ; Sabilillah et al., 2023 ; Widyastuti et al., 2023 ; Wu et al., 2023 ) have influenced these results. These differences highlight the often reported (Provencher et al., 2017 , 2020 ) need for harmonized methods of MP analysis and improved methods for detecting smaller MPs. In our study, no significant background contamination was seen, with only one MP detected from the procedural blanks. Recovery assessments with 250 µm particles yielded an 80% recovery rate for three different polymers tested. All of the tested polymers were fragments or spheres, so the recovery rate for fibers in this study is unknown. Particles smaller than 250 µm were not tested due to difficulty in small particle manipulation. Protocols to assess the recovery of different sizes and shapes of MPs are essential to increase the reproducibility of these results. MP sub-sampling was done in this study to reduce the analysis time of each sample; however, the use of sub-sampling can introduce misestimates of MP concentration (Brandt et al., 2021 ). Sub-sampling recommendations are still being developed, especially for MPs smaller than 50 µm. Previous recommendations suggest that our results should be representative of MPs present but might not capture MP polymers that occurred rarely in our sampling environment (De Frond et al., 2023 ; El Khatib et al., 2023 ). 4.2. Comparison of MPs in Muscle and GI Tract We predicted that the size of the MPs is the most important parameter for potential bioaccumulation, but we also considered other factors that are known to impact particle uptake, such as particle shape, polymer composition, and degradation status. 4.2.1. Concentrations of MPs We detected no plastic particles in our water samples using an established method for detecting small MPs in water (Covernton et al., 2019 ; Dent et al., 2023 ; Green et al., 2018 ; Qaiser et al., 2023 ; Sabilillah et al., 2023 ). Despite our water samples having non-detectable levels of MPs, MPs were detected in the sampled fish, indicating MP presence in our sample sites. Table 2 MP Concentrations in Fish: A comparison of the average concentrations of MPs found in the GI tract and muscle. Concentrations are shown as the average number of MPs per gram of wet weight ± 1 standard deviation. If a range is present, multiple species were sampled in the study. A dash indicates the tissue was not analyzed. N.D. = not detected Study MP Size Limit of Detection (µm) GI Tract Concentration (MPs/g W.W.) Muscle Concentration (MPs/g W.W.) Current Study 2 45 ± 60 6 ± 10 Di Giacinto et al., 2023 1–10 - 0.14–0.27 Su et al., 2019 20 0.1 ± 0.1–8.8 ± 7.4 N.D. Park et al., 2023 20 3.42 ± 3.2 - Soltani et al., 2023 100 0.04 ± 0.05–0.47 ± 0.28 - Wu et al., 2023 100 0.02 ± 0.05 0.01 Both collection site and tissue type affected MP occurrence frequencies. MPs occurred more frequently in the GI tract than in the muscle samples. This trend is generally agreed upon in the literature (Jeyasanta et al., 2023 ; My et al., 2023 ; Pandey et al., 2023 ) with one study finding the opposite trend (Dent et al., 2023 ). The present study’s estimated GI tract MP concentration (45 particles/g w.w) is higher than those in other studies (Table 2 ). The muscle samples had a lower MP concentration than the GI tract samples, but the muscle sample concentration was still greater than most of those previously reported (Table 2 ). A difference in size limits of detection could partly explain this difference, as we were able to detect smaller particles than most previous studies. The absorption of MPs into the GI tract epithelium cannot be determined from our results since both GI tract and GI tract contents were digested together. It has previously been shown that GI tract contents contain higher MP concentrations than just the GI tract epithelium (Curtean-Bănăduc et al., 2023 ; Rosas et al., 2023 ), suggesting that few particles are absorbed by the epithelium from ingested food; however, uptake is known to be in part size-dependent, and the retention and rate of tissue translocation of the smaller MPs found in our study are unknown. 4.2.2. Plastic Sizes The size of MPs found in both the environment and in biota ranges widely throughout the literature. MPs range from 1 µm − 5 mm in commonly agreed definitions (Rochman et al., 2019a ); however, few studies measure the full-size range of these particles. It is common for studies to have minimum size limits of detection that are much higher than the 1 µm theoretical minimum size, or to not report the size limits of detection (Reviewed in Pitt et al., 2024 ). For example, we found that in studies reporting a minimum size detection limit, the median value was 206 µm, with most studies not reporting a minimum size detection limit (Pitt et al., 2024 ). These differences in size detection limits make it challenging to compare the abundance of MP sizes detected in fish tissues, such as the muscle, which is predicted to preferentially accumulate smaller MPs. The current study was able to measure particles 2 µm − 5 mm in size. Studies often find that smaller particles are the most prevalent in the atmosphere (Liao et al., 2021 ), water (Shim et al., 2022 ), and organisms (Valente et al., 2023 ). Our study found the GI tract and muscle MP median lengths to be 24.7 µm and 14.5 µm respectively, sizes that are smaller than the most commonly reported minimum size detection limits for biological samples (Amini-Birami et al., 2023 ; Collard et al., 2017 ; Matluba et al., 2023 ; McIlwraith et al., 2021 ; Widyastuti et al., 2023 ). Other studies in non-GI tract tissues have found MPs larger than those found in the current study (Abbasi et al., 2018 ; Curtean-Bănăduc et al., 2023 ; Esmaeilbeigi et al., 2023 ; Guilhermino et al., 2021 ; Matias et al., 2023 ; McIlwraith et al., 2021 ; My et al., 2023 ; Nawar et al., 2023 ; Sabilillah et al., 2023 ; Sultan et al., 2023 ; Wu et al., 2023 ), but the uptake pathway used by these larger particles is unclear, as in some cases, they are above previously established uptake limits (Lusher et al., 2017 ). The MPs found in the muscle were both smaller in size and size range than those found in the GI tract, implying a size restriction for particles to enter the muscle. It has been suggested that particle translocation from the GI tract through a mechanism called persorption has an upper size limit of 150 µm (Lusher et al., 2017 ). Persorption is the paracellular movement of particles in the desquamation region of epithelial cells (Volkheimer, 1974 ). This mechanism of transport has been previously critiqued as being unlikely and has not been demonstrated since its inception (Hussain et al., 2001 ; O’hagan, 1996 ). The actual upper limit of translocation is uncertain, but previous research suggests that only particles smaller than 21 µm are capable of translocating into tissues (Deng et al., 2017 ; Lusher et al., 2017 ; Huang et al., 2022 ; Jin et al., 2021 ). In the present study, eight (out of ten) of the MPs detected in muscle were smaller than 21 µm. The maximum size for particles found in the muscle was 28 µm. How these particles reached the muscle is unclear, but some phagocytic cells are 25–30 µm in size and might be capable of engulfing and transporting these particles (Lendeckel et al., 2022 ). GI tract absorption of particles is the most likely route of uptake, as particles larger than 10 µm are unlikely to be internalized from the lungs or gills (Prata, 2023 ). We suggest that the MPs detected in the muscle were moved there following phagocytic cell engulfment from the GI tract. The present study is the first to look for the full-size range of MPs in non-GI tract tissues without significant contamination issues. Previous environmental studies with size detection limits lower than 21 µm either did not look for larger MPs (Di Giacinto et al., 2023 ; Ferrante et al., 2022 ) or had a significant amount of background contamination (Akoueson et al., 2020 ; Rasta et al., 2021 ; Su et al., 2019 ); however, it is clear from previous studies that particle translocation is governed by factors other than size, as particles theoretically small enough to translocate have not moved through the intestinal wall (Kim et al., 2020 ; Pyl et al., 2022 ). 4.2.3. Particle Shape The higher proportion of fragments, versus fibers, in our samples compared to previous studies could be due to the smaller size of MPs detected in our study versus these earlier studies (Akoueson et al., 2020 ; Guilhermino et al., 2021 ; Mai et al., 2023 ; Matias et al., 2023 ; Matupang et al., 2023 ; McIlwraith et al., 2021 ; Menéndez et al., 2023 ; Piskuła & Astel, 2023 ; Sánchez-Guerrero-Hernández et al., 2023 ). Previously, fibers have tended to predominate in larger size fractions of MPs, while fragments make up the majority of particles < 100 µm (Liao et al., 2021 ; Piskuła & Astel, 2023 ). On the other hand, some studies that quantified particles down to 20 µm in size have detected primarily fibers, emphasizing that size is not necessarily the major predicting factor for determining particle shape (Kumari et al., 2023 ; Pandey et al., 2023 ; Park et al., 2023 ; Sabilillah et al., 2023 ; Wu et al., 2023 ; Zhu et al., 2023 ). Previously, it has been speculated that fibers are more likely to translocate or be internalized by cells compared to other MP shapes (Ramsperger et al., 2023 ); however, our study contradicts that finding as fibers were not found at a higher frequency in muscle. 4.2.4. Polymer Types Nylon was the predominant polymer (80–88%) in the GI tract samples. While nylon has occasionally been reported as the major polymer in samples spanning a large range of trophic levels (Amini-Birami et al., 2023 ; Covernton et al., 2022 ; Nawar et al., 2023 ; Sánchez-Guerrero-Hernández et al., 2023 ), polypropylene and polyethylene are usually the most common polymers reported in marine organisms (Dent et al., 2023 ; Di Giacinto et al., 2023 ; Giani et al., 2023 ; Kor et al., 2023 ; Mahu et al., 2023 ; Matluba et al., 2023 ; Park et al., 2023 ; Zhu et al., 2023 ). Polypropylene and polyethylene are less dense than water, and so species found near the surface of the water could be more likely to encounter these polymer types. Nylon, on the other hand, is slightly denser than seawater, and so would be more likely to sink to the benthic and benthopelagic environment where killifish dwell. In contrast to the GI tracts, nylon was the only polymer found in the muscle samples. One other study has found nylon at an increased proportion in muscle compared to the GI tract (Sultan et al., 2023 ) with other studies seeing no difference (Menéndez et al., 2023 ). Our results suggest that nylon more readily penetrates into muscle than polyethylene. 4.3. Implications for MP Bioaccumulation We did not calculate a bioaccumulation factor from our results due to a lack of information regarding the water and sediment concentrations of MPs at the collection sites. Our results suggest that few MPs are ultimately internalized to the muscle. MP deposition in the muscle was potentially impacted by the sex and total length of the fish. 4.3.1. Relationship between Fish Length and MP Abundance The long-term sequestration of larger MPs (> 100 µm) has previously been shown to be unlikely (Covernton et al., 2022 ; Giani et al., 2023 ; Matias et al., 2023 ; McIlwraith et al., 2021 ; Valente et al., 2023 ; reviewed in Pitt et al., 2024 ). The bioaccumulation potential, especially for smaller MPs (< 100 µm), has remained unclear, largely due to a lack of information about the distribution and abundance of MPs in non-GI tract tissues; however, our study has started to address this knowledge gap. A positive relationship was observed between fish length and the MP abundance in the GI tract. This finding agrees with the majority of studies (Esmaeilbeigi et al., 2023 ; Guilhermino et al., 2021 ; Jeyasanta et al., 2023 ; Mai et al., 2023 ; Makhdoumi et al., 2021 ; Matupang et al., 2023 ; McIlwraith et al., 2021 ) despite some contradictory evidence (Dent et al., 2023 ; Kor et al., 2023 ; Park et al., 2023 ; Sultan et al., 2023 ). It has been suggested that one reason studies report a positive correlation could be that as fish grow, they can ingest a wider size range of MPs and, consequently, are exposed to more MPs in the environment (Bhattacharjee et al., 2023 ). Larger fish also have increased dietary needs, and so might ingest more prey, thus increasing their incidental MP ingestion. A positive relationship was also seen between fish length and MP abundance and occurrence in the muscle. This contrasts with most of the existing literature, which did not see this trend for non-GI tract tissues (Guilhermino et al., 2021 ; Makhdoumi et al., 2021 ; McIlwraith et al., 2021 ). The lowest reported MP size for some of these studies was approximately 63 µm, which is 31.5 times larger than our lowest reported MP size (Guilhermino et al., 2021 ; McIlwraith et al., 2021 ). It seems likely that MP size influences trends seen regarding fish length. Our results suggest that small MPs, which are often not quantified, are the primary MPs to be found in tissues like the muscle. Killifish increase in length as they age (Abraham, 1985 ), so the correlation between fish total length and muscle MP abundance also could be indicative of bioaccumulation. 4.3.2. Relationship between MP Abundance in the GI Tract and the Muscle There was no observed relationship between the abundance of MPs in the GI tract and in the muscle. This finding agrees with the majority of previous studies (Arafat et al., 2023 ; Gedik et al., 2023 ; Raza et al., 2023 ) with a few conflicting reports (McIlwraith et al., 2021 ; Nawar et al., 2023 ). Generally, this suggests that the MP residence times differ between these tissues, and therefore one tissue cannot be used to predict the content of another. GI tract residence time is short, with previous studies showing rapid elimination of larger MPs (> 250 µm) in killifish (Ohkubo et al., 2020 ). Given the short residence time of MP in the GI tract and the lack of correlation between GI tract and muscle MP abundance, bioaccumulation assessments should not include GI tract data when considering the long-term sequestration potential of MPs. 4.3.3. Other Factors There were several differences between the sites that potentially contributed to the different patterns in MP abundance that we saw including: proximity to a residential area, connection to the ocean, differences in recent weather patterns, and differences in the characteristics of the collected fish; however, the MP water concentrations were not detectable from both collection sites, indicating similar low contamination levels. Only female fish had MPs in muscle samples, and they also had greater GI tract MP abundance. This finding could be confounded by several biases, such as the collected females being predominantly from the Falmouth site and that female fish are larger than male fish; however, a couple of other studies have observed the same trend (Esmaeilbeigi et al., 2023 ; Matupang et al., 2023 ). Overall, relatively few studies have compared male and female fish in terms of the MP content of GI tract and tissues. In the future, more research is needed to investigate the origins of this trend. 4.4. Conclusions There continues to be a dearth of information regarding the distribution of smaller MPs to non-GI tract tissues. This study only detected smaller MPs in the muscle tissues, suggesting a potential upper limit on the sizes of MPs in muscle tissue. This MP abundance was positively correlated with fish total length, indicating that the smaller MPs detected in this study might bioaccumulate. Future studies should focus MP quantification efforts on small MPs in non-GI tract tissues to further investigate this trend. Abbreviations MPs = Microplastics GI = Gastrointestinal FTIR = Fourier-transform infrared spectroscopy PVC = Polyvinyl chloride PET = Polyethylene terephthalate PE = Polyethylene ATR = Attenuated total reflection Declarations 5.1 Availability of Data and Materials The data supporting the findings of this study are available within the paper and its supplementary material and data files. Raw data files (Raman and FTIR spectra) are available from the corresponding author upon reasonable request. 5.2 Competing Interests The authors declare no competing financial interest. 5.3 Funding This research was supported in part by Woods Hole Sea Grant (Award No. NA18OAR4170104, project R/P–89) to M.E.H., N.A., and J.A.P. and by an NSF Graduate Research Fellowship to J.A.P. Additional support was provided by Woods Hole Sea Grant (Award No. NA18OAR4170104, project R/O-59 to S.M.G.) and by the Woods Hole Center for Oceans and Human Health (NIH/NIEHS grant P01ES028938 and NSF grant OCE-1840381 to M.E.H. and N.A.). 5.4 Authors' Contributions JAP: Conceptualization, Formal analysis, Funding acquisition, Methodology, Visualization, Investigation, Writing - original draft, Writing - review & editing. SMG: Methodology, Software, Funding acquisition, Resources, Writing – Review & Editing; SY: Methodology, Software, Writing – Review & Editing; APMM: Methodology, Resources, Writing – Review & Editing; MEH: Conceptualization, Funding acquisition, Methodology, Supervision, Writing - review & editing; NA: Conceptualization, Funding acquisition, Methodology, Resources, Supervision, Writing - review & editing 5.5 Ethics approval All procedures performed in the study were in accordance with the ethical principles described in the Guide for the Care and Use of Laboratory Animals (U.S. National Research Council, Eighth Edition, 2011). Euthanasia was performed according to the American Veterinary Medical Association (AVMA) Guidelines for the Euthanasia of Animals (2013 Edition). The research protocol was approved by the Institutional Animal Care and Use Committee (IACUC) of the Woods Hole Oceanographic Institution (Assurance D16-00381 from the Office of Laboratory Animal Welfare (OLAW) at the U.S. National Institutes of Health). 5.6 Consent to publish Not applicable 5.7 Consent to participate Not applicable 5.8 Acknowledgments Not applicable References Abbasi, S., Soltani, N., Keshavarzi, B., Moore, F., Turner, A., & Hassanaghaei, M. (2018). Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf. Chemosphere , 205 , 80–87. https://doi.org/10.1016/J.CHEMOSPHERE.2018.04.076 Abraham, B. J. (1985). Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). MUMMICHOG AND STRIPED KILLIFISH. Akhbarizadeh, R., Moore, F., & Keshavarzi, B. (2018). Investigating a probable relationship between microplastics and potentially toxic elements in fish muscles from northeast of Persian Gulf. Environmental Pollution , 232 , 154–163. https://doi.org/10.1016/J.ENVPOL.2017.09.028 Akoueson, F., Sheldon, L. M., Danopoulos, E., Morris, S., Hotten, J., Chapman, E., Li, J., & Rotchell, J. M. (2020). A preliminary analysis of microplastics in edible versus non-edible tissues from seafood samples. Environmental Pollution , 263 , 114452. https://doi.org/10.1016/J.ENVPOL.2020.114452 Allen, E. A., Fell, P. E., Peck, M. A., Gieg, J. A., Guthke, C. R., & Newkirk, M. D. (1994). Gut contents of common mummichogs, Fundulus heteroclitus L., in a restored impounded marsh and in natural reference marshes. Estuaries , 17 (2), 462–471. https://doi.org/10.2307 Amini-Birami, F., Keshavarzi, B., Esmaeili, H. R., Moore, F., Busquets, R., Saemi-Komsari, M., Zarei, M., & Zarandian, A. (2023). Microplastics in aquatic species of Anzali wetland: An important freshwater biodiversity hotspot in Iran. Environmental Pollution , 330 , 121762. https://doi.org/10.1016/J.ENVPOL.2023.121762 Arafat, S. T., Tanoiri, H., Yokota, M., Nakano, H., Arakawa, H., Terahara, T., & Kobayashi, T. (2023). Microplastic pollution in the gastrointestinal tract of giant river catfish Sperata seenghala (Sykes, 1839) from the Meghna River, Bangladesh. Environmental Science and Pollution Research , 1 , 1–11. https://doi.org/10.1007/S11356-023-28750-Z/FIGURES/4 Beier, R., & Gebert, A. (1998). Kinetics of particle uptake in the domes of Peyer’s patches. American Journal of Physiology - Gastrointestinal and Liver Physiology , 275 (1 38-1). https://doi.org/10.1152/AJPGI.1998.275.1.G130 Bhattacharjee, Sh., Mandal, B., Das, R., Bhattacharyya, S., Chaudhuri, P., & Mukherjee, A. (2023). Microplastics in gastro-intestinal tract of estuarine fish from the mangrove ecosystem of Indian Sundarbans. Iranian Journal of Fisheries Sciences , 22 (2), 317–338. https://doi.org/10.22092/IJFS.2023.129046 Brandt, J., Fischer, F., Kanaki, E., Enders, K., Labrenz, M., & Fischer, D. (2021). Assessment of Subsampling Strategies in Microspectroscopy of Environmental Microplastic Samples. Frontiers in Environmental Science , 8 , 288. https://doi.org/10.3389/FENVS.2020.579676 Carr, K. E., Hazzard, R. A., Reid, S., & Hodges, G. M. (1996). The effect of size on uptake of orally administered latex microparticles in the small intestine and transport to mesenteric lymph nodes. Pharmaceutical Research , 13 (8), 1205–1209. https://doi.org/10.1023 Collard, F., Gilbert, B., Compère, P., Eppe, G., Das, K., Jauniaux, T., & Parmentier, E. (2017). Microplastics in livers of European anchovies (Engraulis encrasicolus, L.). Environmental Pollution , 229 , 1000–1005. https://doi.org/10.1016/J.ENVPOL.2017.07.089 Colombo, C. V., Fernández-Severini, M. D., Forero-López, A. D., Ardusso, M. G., Rimondino, G. N., Malanca, F. E., & Buzzi, N. S. (2023). Microplastics in commercial seafood: Pleoticus muelleri as a case study in an estuarine environment highly affected by human pressure (Southwestern Atlantic). Environmental Research , 216 , 114738. https://doi.org/10.1016/J.ENVRES.2022.114738 Covernton, G. A., Cox, K. D., Fleming, W. L., Buirs, B. M., Davies, H. L., Juanes, F., Dudas, S. E., & Dower, J. F. (2022). Large size (>100-μm) microplastics are not biomagnifying in coastal marine food webs of British Columbia, Canada. Ecological Applications , 32 (7), e2654. https://doi.org/10.1002/EAP.2654 Covernton, G. A., Pearce, C. M., Gurney-Smith, H. J., Chastain, S. G., Ross, P. S., Dower, J. F., & Dudas, S. E. (2019). Size and shape matter: A preliminary analysis of microplastic sampling technique in seawater studies with implications for ecological risk assessment. Science of The Total Environment , 667 , 124–132. https://doi.org/10.1016/J.SCITOTENV.2019.02.346 Cowger, W., Steinmetz, Z., Gray, A., Munno, K., Lynch, J., Hapich, H., Primpke, S., De Frond, H., Rochman, C., & Herodotou, O. (2021). Microplastic Spectral Classification Needs an Open Source Community: Open Specy to the Rescue! Analytical Chemistry , 93 (21), 7543–7548. https://doi.org/10.1021/ACS.ANALCHEM.1C00123/SUPPL_FILE/AC1C00123_SI_005.ZIP Curtean-Bănăduc, A., Mihuţ, C., Burcea, A., McCall, G. S., Matei, C., & Bănăduc, D. (2023). Screening for Microplastic Uptake in an Urbanized Freshwater Ecosystem: Chondrostoma nasus (Linnaeus, 1758) Case Study. Water 2023, Vol. 15, Page 1578 , 15 (8), 1578. https://doi.org/10.3390/W15081578 De Frond, H., O’Brien, A. M., & Rochman, C. M. (2023). Representative subsampling methods for the chemical identification of microplastic particles in environmental samples. Chemosphere , 310 , 136772. https://doi.org/10.1016/J.CHEMOSPHERE.2022.136772 Deng, Y., Zhang, Y., Lemos, B., & Ren, H. (2017). Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure. Scientific Reports 2017 7:1 , 7 (1), 1–10. https://doi.org/10.1038/srep46687 Dent, A. R., Chadwick, D. D. A., Eagle, L. J. B., Gould, A. N., Harwood, M., Sayer, C. D., & Rose, N. L. (2023). Microplastic burden in invasive signal crayfish (Pacifastacus leniusculus) increases along a stream urbanization gradient. Ecology and Evolution , 13 (5), e10041. https://doi.org/10.1002/ECE3.10041 Di Giacinto, F., Di Renzo, L., Mascilongo, G., Notarstefano, V., Gioacchini, G., Giorgini, E., Bogdanović, T., Petričević, S., Listeš, E., Brkljača, M., Conti, F., Profico, C., Zambuchini, B., Di Francesco, G., Giansante, C., Diletti, G., Ferri, N., & Berti, M. (2023). Detection of microplastics, polymers and additives in edible muscle of swordfish (Xiphias gladius) and bluefin tuna (Thunnus thynnus) caught in the Mediterranean Sea. Journal of Sea Research , 192 , 102359. https://doi.org/10.1016/J.SEARES.2023.102359 El Khatib, D., Langknecht, T. D., Cashman, M. A., Reiss, M., Somers, K., Allen, H., Ho, K. T., & Burgess, R. M. (2023). Assessment of filter subsampling and extrapolation for quantifying microplastics in environmental samples using Raman spectroscopy. Marine Pollution Bulletin , 192 , 115073. https://doi.org/10.1016/J.MARPOLBUL.2023.115073 Enders, K., Lenz, R., Stedmon, C. A., & Nielsen, T. G. (2015). Abundance, size and polymer composition of marine microplastics ≥ 10 μm in the Atlantic Ocean and their modelled vertical distribution. Marine Pollution Bulletin , 100 (1), 70–81. https://doi.org/10.1016/J.MARPOLBUL.2015.09.027 Erni-Cassola, G., Gibson, M. I., Thompson, R. C., & Christie-Oleza, J. A. (2017). Lost, but Found with Nile Red: A Novel Method for Detecting and Quantifying Small Microplastics (1 mm to 20 μm) in Environmental Samples. Environmental Science and Technology , 51 (23), 13641–13648. https://doi.org/10.1021/ACS.EST.7B04512/SUPPL_FILE/ES7B04512_SI_001.PDF Esmaeilbeigi, M., Kazemi, A., Gholizadeh, M., & Rezaeiyeh, R. D. (2023). Microplastics and heavy metals contamination in Atropus atropos and associated health risk assessment in the northwest of the Persian Gulf, Iran. Regional Studies in Marine Science , 57 , 102750. https://doi.org/10.1016/J.RSMA.2022.102750 Ferrante, M., Pietro, Z., Allegui, C., Maria, F., Antonio, C., Pulvirenti, E., Favara, C., Chiara, C., Grasso, A., Omayma, M., Gea, O. C., & Banni, M. (2022). Microplastics in fillets of Mediterranean seafood. A risk assessment study. Environmental Research , 204 , 112247. https://doi.org/10.1016/J.ENVRES.2021.112247 Gedik, K., Eryaşar, A. R., Emanet, M., Şahin, C., & Ceylan, Y. (2023). Monthly microplastics change in European anchovy’s (Engraulis encrasicolus) gastrointestinal tract in the Black Sea. Marine Pollution Bulletin , 194 , 115303. https://doi.org/10.1016/J.MARPOLBUL.2023.115303 Giani, D., Andolina, C., Baini, M., Panti, C., Sciandra, M., Vizzini, S., & Fossi, M. C. (2023). Trophic niche influences ingestion of micro- and mesoplastics in pelagic and demersal fish from the Western Mediterranean Sea. Environmental Pollution , 328 , 121632. https://doi.org/10.1016/J.ENVPOL.2023.121632 Gouin, T. (2020). Toward an Improved Understanding of the Ingestion and Trophic Transfer of Microplastic Particles: Critical Review and Implications for Future Research. Environmental Toxicology and Chemistry , 39 (6), 1119–1137. https://doi.org/10.1002/ETC.4718 Green, D. S., Kregting, L., Boots, B., Blockley, D. J., Brickle, P., da Costa, M., & Crowley, Q. (2018). A comparison of sampling methods for seawater microplastics and a first report of the microplastic litter in coastal waters of Ascension and Falkland Islands. Marine Pollution Bulletin , 137 , 695–701. https://doi.org/10.1016/J.MARPOLBUL.2018.11.004 Guilhermino, L., Martins, A., Lopes, C., Raimundo, J., Vieira, L. R., Barboza, L. G. A., Costa, J., Antunes, C., Caetano, M., & Vale, C. (2021). Microplastics in fishes from an estuary (Minho River) ending into the NE Atlantic Ocean. Marine Pollution Bulletin , 173 , 113008. https://doi.org/10.1016/J.MARPOLBUL.2021.113008 Gulizia, A. M., Brodie, E., Daumuller, R., Bloom, S. B., Corbett, T., Santana, M. M. F., Motti, C. A., Vamvounis, G., Gulizia, A. M., Brodie, E., Daumuller, R., Bloom, S. B., Corbett, T., Santana, M. M. F., Vamvounis, G., & Motti, C. A. (2022). Evaluating the Effect of Chemical Digestion Treatments on Polystyrene Microplastics: Recommended Updates to Chemical Digestion Protocols. Macromolecular Chemistry and Physics , 223 (13), 2100485. https://doi.org/10.1002/MACP.202100485 Hermsen, E., Mintenig, S. M., Besseling, E., & Koelmans, A. A. (2018). Quality Criteria for the Analysis of Microplastic in Biota Samples: A Critical Review. Environmental Science and Technology , 52 (18), 10230–10240. https://doi.org/10.1021/ACS.EST.8B01611 Huang, T., Zhang, W., Lin, T., Liu, S., Sun, Z., Liu, F., Yuan, Y., Xiang, X., Kuang, H., Yang, B., & Zhang, D. (2022). Maternal exposure to polystyrene nanoplastics during gestation and lactation induces hepatic and testicular toxicity in male mouse offspring. Food and Chemical Toxicology , 160 , 112803. https://doi.org/10.1016/J.FCT.2021.112803 Hussain, N., Jaitley, V., & Florence, A. T. (2001). Recent advances in the understanding of uptake of microparticulates across the gastrointestinal lymphatics. Advanced Drug Delivery Reviews , 50 (1–2), 107–142. https://doi.org/10.1016/S0169-409X(01)00152-1 Jeyasanta, K. I., Laju, R. L., Patterson, J., Jayanthi, M., Bilgi, D. S., Sathish, N., & Edward, J. K. P. (2023). Microplastic pollution and its implicated risks in the estuarine environment of Tamil Nadu, India. Science of The Total Environment , 861 , 160572. https://doi.org/10.1016/J.SCITOTENV.2022.160572 Jin, H., Ma, T., Sha, X., Liu, Z., Zhou, Y., Meng, X., Chen, Y., Han, X., & Ding, J. (2021). Polystyrene microplastics induced male reproductive toxicity in mice. Journal of Hazardous Materials , 401 , 123430. https://doi.org/10.1016/J.JHAZMAT.2020.123430 Kim, J., Poirier, D. G., Helm, P. A., Bayoumi, M., & Rochman, C. M. (2020). No evidence of spherical microplastics (10–300 μm) translocation in adult rainbow trout (Oncorhynchus mykiss) after a two-week dietary exposure. PLOS ONE , 15 (9), e0239128. https://doi.org/10.1371/JOURNAL.PONE.0239128 Koelmans, A. A., Mohamed Nor, N. H., Hermsen, E., Kooi, M., Mintenig, S. M., & De France, J. (2019). Microplastics in freshwaters and drinking water: Critical review and assessment of data quality. Water Research , 155 , 410–422. https://doi.org/10.1016/J.WATRES.2019.02.054 Kor, K., Jannat, B., Ershadifar, H., & Ghazilou, A. (2023). Microplastic occurrence in finfish and shellfish from the mangroves of the northern Gulf of Oman. Marine Pollution Bulletin , 189 , 114788. https://doi.org/10.1016/J.MARPOLBUL.2023.114788 Kuhn, M. (2008). Building Predictive Models in R Using the caret Package. Journal of Statistical Software , 28 (5), 1–26. https://doi.org/10.18637/JSS.V028.I05 Kumari, N., Yadav, D. K., Yasha, Khan, P. K., & Kumar, R. (2023). Occurrence of plastics and their characterization in wild caught fish species (Labeo rohita, Wallago attu and Mystus tengara) of River Ganga (India) compared to a commercially cultured species (L. rohita). Environmental Pollution , 334 , 122141. https://doi.org/10.1016/J.ENVPOL.2023.122141 Lebreton, L., Egger, M., & Slat, B. (2019). A global mass budget for positively buoyant macroplastic debris in the ocean. Scientific Reports 2019 9:1 , 9 (1), 1–10. https://doi.org/10.1038/s41598-019-49413-5 Lendeckel, U., Venz, S., & Wolke, C. (2022). Macrophages: shapes and functions. ChemTexts , 8 (2), 1–12. https://doi.org/10.1007/S40828-022-00163-4/TABLES/3 Lenz, R., Enders, K., Stedmon, C. A., MacKenzie, D. M. A., & Nielsen, T. G. (2015). A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement. Marine Pollution Bulletin , 100 (1), 82–91. https://doi.org/10.1016/J.MARPOLBUL.2015.09.026 Li, Y., Shao, L., Wang, W., Zhang, M., Feng, X., Li, W., & Zhang, D. (2020). Airborne fiber particles: Types, size and concentration observed in Beijing. Science of The Total Environment , 705 , 135967. https://doi.org/10.1016/J.SCITOTENV.2019.135967 Liao, Z., Ji, X., Ma, Y., Lv, B., Huang, W., Zhu, X., Fang, M., Wang, Q., Wang, X., Dahlgren, R., & Shang, X. (2021). Airborne microplastics in indoor and outdoor environments of a coastal city in Eastern China. Journal of Hazardous Materials , 417 , 126007. https://doi.org/10.1016/J.JHAZMAT.2021.126007 Löder, M. G. J., Imhof, H. K., Ladehoff, M., Löschel, L. A., Lorenz, C., Mintenig, S., Piehl, S., Primpke, S., Schrank, I., Laforsch, C., & Gerdts, G. (2017). Enzymatic Purification of Microplastics in Environmental Samples. Environmental Science and Technology , 51 (24), 14283–14292. https://doi.org/10.1021/ACS.EST.7B03055 Lusher, A., Hollman, P., & Mendoza-Hill, J. (2017). Microplastics in fisheries and aquaculture: status of knowledge on their occurrence and implications for aquatic organisms and food safety. FAO. Mahu, E., Datsomor, W. G., Folorunsho, R., Fisayo, J., Crane, R., Marchant, R., Montford, J., Boateng, M. C., Edusei Oti, M., Oguguah, M. N., & Gordon, C. (2023). Human health risk and food safety implications of microplastic consumption by fish from coastal waters of the eastern equatorial Atlantic Ocean. Food Control , 145 , 109503. https://doi.org/10.1016/J.FOODCONT.2022.109503 Mai, H., Thao Nhi Ngo, T., Thien Nguyen, D., Hoi Bui, V., Duong Dao, T., Thom Dang, T., Manh Do, V., Quoc Viet, H., Giay, C., Noi, H., & Nam, V. (2023). Preliminary assessment of microplastic pollution in commercial freshwater fish species collected from four districts in Bac Ninh province. Vietnam Journal of Science and Technology , 61 (4), 629–639. https://doi.org/10.15625/2525-2518/17926 Makhdoumi, P., Hossini, H., Nazmara, Z., Mansouri, K., & Pirsaheb, M. (2021). Occurrence and exposure analysis of microplastic in the gut and muscle tissue of riverine fish in Kermanshah province of Iran. Marine Pollution Bulletin , 173 , 112915. https://doi.org/10.1016/J.MARPOLBUL.2021.112915 Matias, R. S., Gomes, S., Barboza, L. G. A., Salazar-Gutierrez, D., Guilhermino, L., & Valente, L. M. P. (2023). Microplastics in water, feed and tissues of European seabass reared in a recirculation aquaculture system (RAS). Chemosphere , 335 , 139055. https://doi.org/10.1016/J.CHEMOSPHERE.2023.139055 Matluba, M., Ahmed, M. K., Chowdhury, K. M. A., Khan, N., Ashiq, M. A. R., & Islam, M. S. (2023). The pervasiveness of microplastic contamination in the gastrointestinal tract of fish from the western coast of Bangladesh. Marine Pollution Bulletin , 193 , 115145. https://doi.org/10.1016/J.MARPOLBUL.2023.115145 Matsui, H., Arrivo, S. M., Valentini, J. J., & Weber, J. N. (2000). Resonance Raman studies of photoinduced decomposition of nylon-6, 6: product identification and mechanistic determination. Macromolecules, 33(15), 5655-5664. Matupang, D. M., Zulkifli, H. I., Arnold, J., Lazim, A. M., Ghaffar, M. A., & Musa, S. M. (2023). Tropical sharks feasting on and swimming through microplastics: First evidence from Malaysia. Marine Pollution Bulletin , 189 , 114762. https://doi.org/10.1016/J.MARPOLBUL.2023.114762 McIlwraith, H. K., Kim, J., Helm, P., Bhavsar, S. P., Metzger, J. S., & Rochman, C. M. (2021). Evidence of Microplastic Translocation in Wild-Caught Fish and Implications for Microplastic Accumulation Dynamics in Food Webs. Environmental Science and Technology , 55 (18), 12372–12382. https://doi.org/10.1021/ACS.EST.1C02922/SUPPL_FILE/ES1C02922_SI_002.XLSX Menéndez, D., Blanco-Fernandez, C., Machado-Schiaffino, G., Ardura, A., & Garcia-Vazquez, E. (2023). High microplastics concentration in liver is negatively associated with condition factor in the Benguela hake Merluccius polli. Ecotoxicology and Environmental Safety , 262 , 115135. https://doi.org/10.1016/J.ECOENV.2023.115135 My, T. T. A., Dat, N. D., & Hung, N. Q. (2023). Occurrence and Characteristics of Microplastics in Wild and Farmed Shrimps Collected from Cau Hai Lagoon, Central Vietnam. Molecules , 28 (12), 4634. https://doi.org/10.3390/MOLECULES28124634/S1 Nawar, N., Rahman, M. M., Chowdhury, F. N., Marzia, S., Ali, M. M., Akbor, M. A., Siddique, M. A. B., Khatun, M. A., Shahjalal, M., Huque, R., & Malafaia, G. (2023). Characterization of microplastic pollution in the Pasur river of the Sundarbans ecosystem (Bangladesh) with emphasis on water, sediments, and fish. Science of The Total Environment , 868 , 161704. https://doi.org/10.1016/J.SCITOTENV.2023.161704 Nordberg, G. F. (2009). Historical perspectives on cadmium toxicology. Toxicology and Applied Pharmacology , 238 (3), 192–200. https://doi.org/10.1016/J.TAAP.2009.03.015 O’hagan, D. T. (1996). The intestinal uptake of particles and the implications for drug and antigen delivery. J. Anal , 189 , 477–482. Ohkubo, N., Ito, M., Hano, T., Kono, K., & Mochida, K. (2020). Estimation of the uptake and gut retention of microplastics in juvenile marine fish: Mummichogs (Fundulus heteroclitus) and red seabreams (Pagrus major). Marine Pollution Bulletin , 160 , 111630. https://doi.org/10.1016/J.MARPOLBUL.2020.111630 Pandey, N., Verma, R., Patnaik, S., & Anbumani, S. (2023). Abundance, characteristics, and risk assessment of microplastics in indigenous freshwater fishes of India. Environmental Research , 218 , 115011. https://doi.org/10.1016/J.ENVRES.2022.115011 Park, B., Kim, S. K., Joo, S., Kim, J. S., Jo, K., Song, N. S., Im, J., Lee, H. J., Kim, S. W., Lee, S. Bin, Kim, S., Lee, Y., Kim, B. Y., & Kim, T. W. (2023). Microplastics in large marine animals stranded in the Republic of Korea. Marine Pollution Bulletin , 189 , 114734. https://doi.org/10.1016/J.MARPOLBUL.2023.114734 Phan, S., Padilla-Gamiño, J. L., & Luscombe, C. K. (2022). The effect of weathering environments on microplastic chemical identification with Raman and IR spectroscopy: Part I. polyethylene and polypropylene. Polymer Testing , 116 , 107752. https://doi.org/10.1016/J.POLYMERTESTING.2022.107752 Piskuła, P., & Astel, A. M. (2023). Microplastics in Commercial Fishes and By-Catch from Selected FAO Major Fishing Areas of the Southern Baltic Sea. Animals 2023, Vol. 13, Page 458 , 13 (3), 458. https://doi.org/10.3390/ANI13030458 Pitt, J. A., Aluru, N., & Hahn, M. E. (2024). Microplastics in Marine Food Webs. In S. Shumway & E. Ward (Eds.), Plastics in the Sea: Occurrence and Impacts . Academic Press. Prata, J. C. (2023). Microplastics and human health: Integrating pharmacokinetics. Https://Doi.Org/10.1080/10643389.2023.2195798 , 53 (16), 1489–1511. https://doi.org/10.1080/10643389.2023.2195798 Provencher, J. F., Ammendolia, J., Rochman, C. M., & Mallory, M. L. (2019). Assessing plastic debris in aquatic food webs: what we know and don’t know about uptake and trophic transfer. Environmental Reviews , 27 (3), 304–317. https://doi.org/10.1139/er-2018-0079 Provencher, J. F., Bond, A. L., Avery-Gomm, S., Borrelle, S. B., Bravo Rebolledo, E. L., Hammer, S., Kühn, S., Lavers, J. L., Mallory, M. L., Trevail, A., & Van Franeker, J. A. (2017). Quantifying ingested debris in marine megafauna: a review and recommendations for standardization. Analytical Methods , 9 (9), 1454–1469. https://doi.org/10.1039/C6AY02419J Provencher, J. F., Covernton, G. A., Moore, R. C., Horn, D. A., Conkle, J. L., & Lusher, A. L. (2020). Proceed with caution: The need to raise the publication bar for microplastics research. Science of The Total Environment , 748 , 141426. https://doi.org/10.1016/J.SCITOTENV.2020.141426 Pyl, M., Taylor, A., Oberhänsli, F., Swarzenski, P., Hussamy, L., Besson, M., Danis, B., & Metian, M. (2022). Size-dependent transfer of microplastics across the intestinal wall of the echinoid Paracentrotus lividus. Aquatic Toxicology , 250 , 106235. https://doi.org/10.1016/J.AQUATOX.2022.106235 Qaiser, N., Sidra, S., Javid, A., Iqbal, A., Amjad, M., Azmat, H., Arooj, F., Farooq, K., Nimra, A., & Ali, Z. (2023). Microplastics abundance in abiotic and biotic components along aquatic food chain in two freshwater ecosystems of Pakistan. Chemosphere , 313 , 137177. https://doi.org/10.1016/J.CHEMOSPHERE.2022.137177 Ramsperger, A. F. R. M., Bergamaschi, E., Panizzolo, M., Fenoglio, I., Barbero, F., Peters, R., Undas, A., Purker, S., Giese, B., Lalyer, C. R., Tamargo, A., Moreno-Arribas, M. V., Grossart, H. P., Kühnel, D., Dietrich, J., Paulsen, F., Afanou, A. K., Zienolddiny-Narui, S., Eriksen Hammer, S., … Laforsch, C. (2023). Nano- and microplastics: a comprehensive review on their exposure routes, translocation, and fate in humans. NanoImpact , 29 , 100441. https://doi.org/10.1016/J.IMPACT.2022.100441 Rasta, M., Sattari, M., Taleshi, M. S., & Namin, J. I. (2021). Microplastics in different tissues of some commercially important fish species from Anzali Wetland in the Southwest Caspian Sea, Northern Iran. Marine Pollution Bulletin , 169 , 112479. https://doi.org/10.1016/J.MARPOLBUL.2021.112479 Raza, M. H., Jabeen, F., Ikram, S., & Zafar, S. (2023). Characterization and implication of microplastics on riverine population of the River Ravi, Lahore, Pakistan. Environmental Science and Pollution Research , 30 (3), 6828–6848. https://doi.org/10.1007/S11356-022-22440-Y/FIGURES/17 Remy, F., Collard, F., Gilbert, B., Compère, P., Eppe, G., & Lepoint, G. (2015). When Microplastic Is Not Plastic: The Ingestion of Artificial Cellulose Fibers by Macrofauna Living in Seagrass Macrophytodetritus. Environmental Science and Technology , 49 (18), 11158–11166. https://doi.org/10.1021/ACS.EST.5B02005 Renner, G., Nellessen, A., Schwiers, A., Wenzel, M., Schmidt, T. C., & Schram, J. (2019). Data preprocessing & evaluation used in the microplastics identification process: A critical review & practical guide. TrAC Trends in Analytical Chemistry , 111 , 229–238. https://doi.org/10.1016/J.TRAC.2018.12.004 Ricker, WE. (1975). Computation and interpretation of biological statistics of fish populations. Fish. Res. Board Can. Bull. , 191 , 1–382. https://cir.nii.ac.jp/crid/1573950400225789696 Rochman, C. M., Brookson, C., Bikker, J., Djuric, N., Earn, A., Bucci, K., Athey, S., Huntington, A., McIlwraith, H., Munno, K., Frond, H. De, Kolomijeca, A., Erdle, L., Grbic, J., Bayoumi, M., Borrelle, S. B., Wu, T., Santoro, S., Werbowski, L. M., … Hung, C. (2019a). Rethinking microplastics as a diverse contaminant suite. Environmental Toxicology and Chemistry , 38 (4), 703–711. https://doi.org/10.1002/ETC.4371 Rochman, C. M., Brookson, C., Bikker, J., Djuric, N., Earn, A., Bucci, K., Athey, S., Huntington, A., McIlwraith, H., Munno, K., Frond, H. De, Kolomijeca, A., Erdle, L., Grbic, J., Bayoumi, M., Borrelle, S. B., Wu, T., Santoro, S., Werbowski, L. M., … Hung, C. (2019b). Rethinking microplastics as a diverse contaminant suite. Environmental Toxicology and Chemistry , 38 (4), 703–711. https://doi.org/10.1002/ETC.4371 Rosas, B. R. C., Sakthi, J. S., Barjau-González, E., Rodríguez-González, F., Galván-Magaña, F., Ramírez, S. F., Gómez-Chávez, F., Sarkar, S. K., & Jonathan, M. P. (2023). First account of microplastics in pelagic sporting dolphinfish from the eastern Mexican coast of Baja California Sur. Environmental Toxicology and Pharmacology , 100 , 104153. https://doi.org/10.1016/J.ETAP.2023.104153 Sabilillah, A. M., Palupi, F. R., Adji, B. K., & Nugroho, A. P. (2023). Health risk assessment and microplastic pollution in streams through accumulation and interaction by heavy metals. Global Journal of Environmental Science and Management , 9 (4), 719–740. https://doi.org/10.22034/GJESM.2023.04.05 Sánchez-Guerrero-Hernández, M. J., González-Fernández, D., Sendra, M., Ramos, F., Yeste, M. P., & González-Ortegón, E. (2023). Contamination from microplastics and other anthropogenic particles in the digestive tracts of the commercial species Engraulis encrasicolus and Sardina pilchardus. Science of The Total Environment , 860 , 160451. https://doi.org/10.1016/J.SCITOTENV.2022.160451 Santos, R. G., Machovsky-Capuska, G. E., & Andrades, R. (2021). Plastic ingestion as an evolutionary trap: Toward a holistic understanding. Science , 373 (6550), 56–60. https://doi.org/10.1126/SCIENCE.ABH0945/SUPPL_FILE/ABH0945_SANTOS_SM.PDF Shim, W. J., Kim, S. K., Lee, J., Eo, S., Kim, J. S., & Sun, C. (2022). Toward a long-term monitoring program for seawater plastic pollution in the north Pacific Ocean: Review and global comparison. Environmental Pollution , 311 , 119911. https://doi.org/10.1016/J.ENVPOL.2022.119911 Su, L., Deng, H., Li, B., Chen, Q., Pettigrove, V., Wu, C., & Shi, H. (2019). The occurrence of microplastic in specific organs in commercially caught fishes from coast and estuary area of east China. Journal of Hazardous Materials , 365 , 716–724. https://doi.org/10.1016/J.JHAZMAT.2018.11.024 Suedel, B. C., Boraczek, J. A., Peddicord, R. K., Clifford, P. A., & Dillon, T. M. (1994). Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems. Reviews of Environmental Contamination and Toxicology , 136 , 21–89. https://doi.org/10.1007/978-1-4612-2656-7_2/COVER Sultan, M. B., Rahman, M. M., Khatun, M. A., Shahjalal, M., Akbor, M. A., Siddique, M. A. B., Huque, R., & Malafaia, G. (2023). Microplastics in different fish and shellfish species in the mangrove estuary of Bangladesh and evaluation of human exposure. Science of The Total Environment , 858 , 159754. https://doi.org/10.1016/J.SCITOTENV.2022.159754 Tabata, Y., Inoue, Y., & Ikada, Y. (1996). Size effect on systemic and mucosal immune responses induced by oral administration of biodegradable microspheres. Vaccine , 14 (17–18), 1677–1685. https://doi.org/10.1016/S0264-410X(96)00149-1 Thompson, J. S. (2015). Size-Selective Foraging of Adult Mummichogs, Fundulus heteroclitus, in Intertidal and Subtidal Habitats. Estuaries and Coasts , 38 (5), 1535–1544. https://doi.org/10.1007/S12237-014-9913-3/FIGURES/3 Valente, T., Costantini, M. L., Careddu, G., Berto, D., Piermarini, R., Rampazzo, F., Sbrana, A., Silvestri, C., Ventura, D., & Matiddi, M. (2023). Tracing the route: Using stable isotope analysis to understand microplastic pathways through the pelagic-neritic food web of the Tyrrhenian Sea (Western Mediterranean). Science of The Total Environment , 885 , 163875. https://doi.org/10.1016/J.SCITOTENV.2023.163875 Volkheimer, G. (1974). Passage of particles through the wall of the gastrointestinal tract. Environmental Health Perspectives , 9 , 215–225. https://doi.org/10.1289/EHP.749215 Widyastuti, S., Susmana Abidin, A., Hikmaturrohmi, H., Tri, B., Ilhami, K., Sofian, N., Kurniawan, H., Jupri, A., Candri, D. A., Frediansyah, A., & Prasedya, E. S. (2023). Microplastic Contamination in Different Marine Species of Bintaro Fish Market, Indonesia. Sustainability 2023, Vol. 15, Page 9836 , 15 (12), 9836. https://doi.org/10.3390/SU15129836 Wu, L., Dai, X., Xu, J., Ou, D., Wang, L., Lin, H., He, W., Lin, H., Du, R., Huang, H., Li, W., & Pan, Z. (2023). Assessment of microplastic contamination in an eastern Pacific tuna (Katsuwonus pelamis) and evaluation of its health risk implication through molecular docking and metabolomics studies. Food Chemistry , 426 , 136507. https://doi.org/10.1016/J.FOODCHEM.2023.136507 Zhu, W., Liu, W., Chen, Y., Liao, K., Yu, W., & Jin, H. (2023). Microplastics in Antarctic krill (Euphausia superba) from Antarctic region. Science of The Total Environment , 870 , 161880. https://doi.org/10.1016/J.SCITOTENV.2023.161880 Additional Declarations No competing interests reported. Supplementary Files PittSupplementalMaterial.pdf Cite Share Download PDF Status: Published Journal Publication published 01 Nov, 2024 Read the published version in Microplastics and Nanoplastics → Version 1 posted Editorial decision: Revision requested 19 Sep, 2024 Reviews received at journal 17 Sep, 2024 Reviews received at journal 16 Sep, 2024 Reviewers agreed at journal 27 Aug, 2024 Reviewers agreed at journal 25 Aug, 2024 Reviewers invited by journal 25 Aug, 2024 Editor assigned by journal 15 Aug, 2024 Submission checks completed at journal 15 Aug, 2024 First submitted to journal 14 Aug, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4916090","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":350661322,"identity":"67721167-946e-4124-8c0b-1eb9d24c8b5c","order_by":0,"name":"Jordan A. Pitt","email":"","orcid":"","institution":"Woods Hole Oceanographic Institution, Woods Hole, MA","correspondingAuthor":false,"prefix":"","firstName":"Jordan","middleName":"A.","lastName":"Pitt","suffix":""},{"id":350661323,"identity":"73e551f1-1e6d-4f6d-a431-be73f66a2192","order_by":1,"name":"Scott M. Gallager","email":"","orcid":"","institution":"CoastalOceanVision, Inc., 10 Edgerton Drive, North Falmouth, MA","correspondingAuthor":false,"prefix":"","firstName":"Scott","middleName":"M.","lastName":"Gallager","suffix":""},{"id":350661324,"identity":"20af5431-ff38-4288-a302-354918620159","order_by":2,"name":"Sarah Youngs","email":"","orcid":"","institution":"Woods Hole Oceanographic Institution, Woods Hole, MA","correspondingAuthor":false,"prefix":"","firstName":"Sarah","middleName":"","lastName":"Youngs","suffix":""},{"id":350661325,"identity":"189f6532-f6de-4297-87ab-5938523a4223","order_by":3,"name":"Anna P. M. Michel","email":"","orcid":"","institution":"Woods Hole Oceanographic Institution, Woods Hole, MA","correspondingAuthor":false,"prefix":"","firstName":"Anna","middleName":"P. M.","lastName":"Michel","suffix":""},{"id":350661326,"identity":"79f88c97-1823-43c4-9f89-644c89a9477a","order_by":4,"name":"Mark E. Hahn","email":"","orcid":"","institution":"Woods Hole Oceanographic Institution, Woods Hole, MA","correspondingAuthor":false,"prefix":"","firstName":"Mark","middleName":"E.","lastName":"Hahn","suffix":""},{"id":350661327,"identity":"72cb5e6d-1986-4126-944e-ae9bf28f7db4","order_by":5,"name":"Neelakanteswar Aluru","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAq0lEQVRIiWNgGAWjYFAC5gYgYcNgwMAIZLARpQWkkiGNdC2HgVpAgBgt5uwH26Qr284nbmdvbmD4UHaYsBbLnsQ2ybNttxN39hxsYJxxjggtBgeAWhrbbuduuJHYwMzbRoyW8w9BWs5BtPwlSssNsC0HIFoYidPysNmy4Vxy/YYzBxsO9pxLJ8ZhyQdvNpTZGRscb3/44EeZNWEtKOAAiepHwSgYBaNgFOACAKZsQtHJ1gTzAAAAAElFTkSuQmCC","orcid":"","institution":"Woods Hole Oceanographic Institution, Woods Hole, MA","correspondingAuthor":true,"prefix":"","firstName":"Neelakanteswar","middleName":"","lastName":"Aluru","suffix":""}],"badges":[],"createdAt":"2024-08-14 22:14:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4916090/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4916090/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s43591-024-00101-w","type":"published","date":"2024-11-01T16:20:15+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":64304135,"identity":"640a8dab-0d5a-4afe-a312-a57ad37af70b","added_by":"auto","created_at":"2024-09-11 12:25:04","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":24704,"visible":true,"origin":"","legend":"\u003cp\u003eMap of southeastern Massachusetts showing the two collection sites (Falmouth, MA, Bourne, MA). Geographical coordinates and environmental parameters at the collection sites are provided in supplemental information (Table S1).\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/2a36f8aa7facbd8377776ada.jpg"},{"id":64303674,"identity":"5d2869dd-58a9-47c2-bd26-e8c0be481129","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":35990,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic Workflow:\u003c/strong\u003e Illustration of sample processing and analysis of tissue samples using Fourier-transform infrared spectroscopy (FTIR; particles \u0026gt; 25 µm) and Raman spectroscopy (particles 2 - 25 µm). Data analysis was done by matching the sample spectra to a reference library using OpenSpecy.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/fd4ab15ec704b5292c66802a.jpg"},{"id":64303666,"identity":"97120bf3-c685-4ae0-b32f-5dcf5d073508","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":51740,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eExamples of Spectra. \u003c/strong\u003eThe r value reflects Pearson's r correlation for the sample and reference spectra. The reference spectra are shown in black, and the sample spectra are shown in coral. Spectra included in analysis had low background noise and few extraneous peaks. Spectra excluded from analysis due to the large number of non-matching peaks.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/7a6ecaaf8cc6cdb89e5cf31a.jpg"},{"id":64303669,"identity":"0e1bde93-12b9-471b-9acc-476e8609f957","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":32289,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePlastic Occurrence and Concentration in Samples: \u003c/strong\u003eSamples collected in Falmouth are shown in blue, and samples collected in Bourne are shown in green. (A) Graph showing percentage of samples that were found to contain microplastics for the three sample types studied (water, GI tract, and muscle). Numbers over bars indicate the percentage found. (B) Box and whisker plot showing the minimum and maximum number of microplastics found per gram of tissue (wet weight). Data were corrected to account for the whole sample based on the observed 8% of the filter that was analyzed. The solid line indicates the median concentration.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/056c486f7efdc4fa25d398ec.jpg"},{"id":64303668,"identity":"5dabc85f-11a0-420d-9c67-588cf1d539e1","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":44295,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePlastic Size Distribution: \u003c/strong\u003eGI tract samples shown in brown. Muscle samples shown in tan. Violin plots the particles. (A) Full size range showing the lengths of microplastics in microns using a logarithmic scale. (B) Full range of the aspect ratios (length/width) for microplastics using a logarithmic scale. (C) Percentage of particles in samples classified as fragment (aspect ratio \u0026lt; 2) or fiber (aspect ratio \u0026gt; 2).\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/3b448ce568ecbee06a55415f.jpg"},{"id":64304136,"identity":"34342d58-ea6e-4b95-b905-30b548a27ef2","added_by":"auto","created_at":"2024-09-11 12:25:04","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":39084,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMicroplastic Polymer Frequencies: \u003c/strong\u003e(A) Total number of microplastics found in the samples color-coded by polymer type. Data were corrected to account for the whole sample based on the observed 8% of the filter that was analyzed. (B) Percentages of the different polymers present in the GI tract and muscle samples.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/59336ae9f470af97092fd1d9.jpg"},{"id":64303675,"identity":"37511574-49c9-4d89-8910-0032a7b2261d","added_by":"auto","created_at":"2024-09-11 12:17:05","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":26302,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eRelationship between Fish Total Length and Microplastic Abundance: \u003c/strong\u003eScatter plot showing the relationship between the total length of a fish and the number of microplastics present. Data were corrected to account for the whole sample based on the observed 8% of the filter that was analyzed. Data was not normalized by wet weight. The Falmouth samples are shown in blue (n=8), and the Bourne samples (n=10) are shown in green. GI tract samples are shown in a darker shade than the muscle samples.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/0740a138221f799722c9d9d5.jpg"},{"id":64303670,"identity":"5292b7ce-d49f-42d1-8c59-25feea14bf2d","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":51441,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMicroplastic Abundance Relationships with Fish Total Length and Sex: \u003c/strong\u003eData is corrected to account for the whole sample based on the observed 8% and normalized by tissue wet weight. (A-C) Linear regression lines with dotted 95% confidence intervals are shown. Correlation refers to the Spearman (nonparametric) correlation analysis between the two variables. (A) Scatter plot showing the relationship between the total length of a fish and the number of MPs in the GI tract. (B) Scatter plot showing the relationship between the fish total length and number of MPs in the muscle. (C) Scatter plot showing the relationship between GI tract MP concentration and Muscle MP concentration. (D) A box and whisker plot depicting the minimum and maximum concentration of microplastic particles (number of particles/g of tissue w.w.) for the males and females collected. Significance is indicated with an * (p-value \u0026lt; 0.05).\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/6c822aa447d3ec06d52af872.jpg"},{"id":68207106,"identity":"7ade3a04-368a-45d4-aae8-c1ffe5f70755","added_by":"auto","created_at":"2024-11-04 16:35:01","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1326595,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/3a2314d7-ec63-4845-8074-b05d6b1c765f.pdf"},{"id":64303673,"identity":"a6bac27e-729b-413f-9273-6239febca98c","added_by":"auto","created_at":"2024-09-11 12:17:04","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1484883,"visible":true,"origin":"","legend":"","description":"","filename":"PittSupplementalMaterial.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4916090/v1/387926ebdfa8dd5d603a2170.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eThe abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eFundulus heteroclitus\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e)\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eUnderstanding the fate of plastics in the ocean is challenging, in part, because plastics are an incredibly diverse suite of contaminants (Rochman et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2019a\u003c/span\u003e). The size, surface chemistry, polymer type, state of degradation, and additives present can all influence the distribution and fate of microplastics (1 \u0026micro;m\u0026thinsp;\u0026lt;\u0026thinsp;particle\u0026thinsp;\u0026lt;\u0026thinsp;5 mm; MPs) in the environment (Rochman et al., \u003cspan citationid=\"CR82\" class=\"CitationRef\"\u003e2019b\u003c/span\u003e). The exact influence of these factors on particle abundance and distribution in the environment is still poorly understood due to analytical limitations and a lack of harmonized methods (Koelmans et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePlastic ingestion is widespread, having been documented in more than 1,565 aquatic and terrestrial species (Santos et al., \u003cspan citationid=\"CR86\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Even though ingestion is well-documented, the bioaccumulation potential of microplastics is not well understood. Bioaccumulation is classically defined as the buildup of a material in an organism over its lifetime (Nordberg, \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Suedel et al., \u003cspan citationid=\"CR89\" class=\"CitationRef\"\u003e1994\u003c/span\u003e); however, the movement of MPs is likely to be more constrained due to their large particulate nature. The ultimate fate of these ingested MPs is both complex and unknown.\u003c/p\u003e \u003cp\u003eOne of the key challenges is that small MPs (smaller than 50 \u0026micro;m), the most prevalent size of environmental plastics (Lebreton et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), are difficult to find and identify in environmental samples (Lebreton et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Smaller particles can often be misidentified as MPs due to a lack of distinguishing characteristics as the particles decrease in size (Lenz et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Remy et al., \u003cspan citationid=\"CR78\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). The abundance of MPs is expected to increase with decreasing size, but there is little information regarding the movement and fate of particles smaller than 50 \u0026micro;m in aquatic environments (Enders et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Erni-Cassola et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In addition to being more abundant in the environment, smaller MPs are also more likely to translocate from the gastrointestinal (GI) tract into internal tissues (Lusher et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Therefore, having an accurate size distribution of ingested MPs is critical to understanding exposure and, ultimately, the risk that MPs pose to marine animals.\u003c/p\u003e \u003cp\u003eThere is still much to discover regarding the characteristics of particles that govern MP translocation into non-GI tract tissues since the majority of published data examines plastic exclusively in the GI tract (Gouin, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Pitt et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Without this information, the implications of ingestion for bioaccumulation, trophic transfer, and biomagnification of MPs cannot be predicted (Provencher et al., \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Current research suggests that bioaccumulation of MPs is unlikely, but this prediction is limited to particles larger than 100 \u0026micro;m, emphasizing the need for research on the accumulation of smaller MPs in tissues (Covernton et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSmaller MPs are often not quantified in tissues due to analytical challenges (Hermsen et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Provencher et al., \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) and high levels of background contamination (Hermsen et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; L\u0026ouml;der et al., \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). The objective of this study was to quantify the full-size range of MPs using strict quality control procedures to reduce background contamination. Through this approach, we aimed to distinguish differences in characteristics of MPs detected in the GI tract and muscle of Atlantic killifish (\u003cem\u003eFundulus heteroclitus\u003c/em\u003e) and address the bioaccumulation potential of the under-reported small MPs.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003ch2\u003e2.1 Materials \u003c/h2\u003e\n\u003cp\u003ePyrex glassware was used whenever possible during this study. Whatman (grade 4; 25 \u0026mu;m pore size) and nitrocellulose (pore size of 1 \u0026mu;m) filter papers (Sigma Aldrich) were used for Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy analysis. Minnow traps were used for collecting Atlantic killifish.\u003c/p\u003e\n\u003ch2\u003e2.2 Quality Control\u003c/h2\u003e\n\u003cp\u003eWe followed the quality control criteria established by Hermsen et al. (2018). All water samples and solutions were filtered through a 0.2 \u0026mu;m filter prior to use. All sample processing apparatus (glass Erlenmeyer flasks and ceramic Buchner funnels) were combusted in a muffle furnace (Fisher Scientific Isotemp Programmable Forced-Draft Furnace) at 500 ℃ for 5 h. Glassware that could not be combusted in the furnace was rinsed three times with both acetone and filtered water prior to use. All work surfaces were wiped down with ethanol prior to working with samples. Sample manipulation took place in a laminar flow hood (AirClean 600 PCR Workstation). Samples were not exposed to ambient air. When the samples were not being actively manipulated, they were covered with aluminum foil. While working with samples, a 100% cotton jumpsuit was worn to prevent contamination from polyester clothing. During sample processing, occupancy of the room was kept to a single person. Procedural blanks were used for every 5 samples. \u003c/p\u003e\n\u003ch2\u003e2.3 Fish collection and tissue sampling\u003c/h2\u003e\n\u003cp\u003eAtlantic killifish were collected using minnow traps from two locations in Buzzards Bay, Massachusetts (Fig. 1). The sampling dates, coordinates, number of fish collected, and the environmental conditions are shown in Table S1. Fish were immediately euthanized using MS222 (1 g/L) buffered with sodium bicarbonate. Fish were kept in an aluminum-foil lined bucket during transport. The total length and weight, sex, and tissue wet weights were recorded upon collection. Prior to dissection, fish were rinsed three times with 0.2 \u0026mu;m filtered water to remove any loose particles on the fish\u0026rsquo;s skin. The GI tract and a section of the dorsal muscle (without skin) were collected. The total GI tract, including contents, were used in our analysis. Tissues were stored in plastic-free aluminum foil at -80 \u0026deg;C. All collected fish were considered mature as they exceeded 3.2 cm or 3.8 cm for males and females, respectively, and they were in good overall health according to the calculated condition factors (Abraham, 1985). Based on length-age relationships (Abraham, 1985), the collected fish from Bourne, MA appear to be a couple of years younger than the collected fish from Falmouth, MA.\u003c/p\u003e\n\u003cp\u003eAt both sampling sites, we collected water samples in 1 liter glass jars. The jars were rinsed three times in water from the collection site prior to sample collection. To prevent air contamination, the jars were immersed underwater prior to opening. Duplicate water samples were collected from each site. Samples were stored at room temperature (20 - 25 ℃).\u003c/p\u003e\n\u003ch2\u003e2.4 Sample Digestion\u003c/h2\u003e\n\u003cp\u003eA flow chart of the sample processing and analysis is shown in Figure 2. Tissue samples were digested with 10% KOH (3x sample wet weight) at 60 ℃ for 48 h (Fig. 2). KOH digestion at this temperature has previously been shown to not degrade MPs (Gulizia et al., 2022). Digests were neutralized with a combination of sodium bicarbonate (0.05 g/mL) and 10% HCl (0.54 mL HCl/mL KOH) prior to filtration. Particles in the samples were size fractionated by filtering initially through a 25 \u0026mu;m pore-size filter followed by a 1 \u0026mu;m filter (Fig. 2). Filters were stored in plastic-free aluminum tins until analysis. The 25 \u0026mu;m pore-size filter was used for FTIR spectroscopy analysis and the 1 \u0026mu;m filter was used for Raman spectroscopy (Fig. 2). Size fractionation was used to analyze samples more efficiently. Raman spectroscopy is more accurate at identifying particles smaller than 20 \u0026mu;m in length, and FTIR is a more efficient method for particles \u0026gt;20 \u0026mu;m in length (De Frond et al., 2023). \u003c/p\u003e\n\u003ch2\u003e2.5 Particle Recovery experiments\u003c/h2\u003e\n\u003cp\u003eParticle recovery experiments were conducted using polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyethylene (PE) particles (250 \u0026mu;m) dyed with 300 \u0026mu;L of Nile Red (10 \u0026mu;g/mL). Blue mussel (\u003cem\u003eMytilus edulis\u003c/em\u003e) tissue was used to determine the particle recovery from the MP isolation process from biological tissues. Fifty particles from each polymer type were manually added to whole mussel tissue (\u003cem\u003eMytilus \u003c/em\u003eedulis) in Erlenmeyer flasks. The mussels were then digested for 48 h as in section 2.4. The resulting digests were then filtered through 25 \u0026mu;m pore-size filters. Each flask was washed three times with filtered water. The number of particles on the filter were counted under a dissecting microscope. There was 80% recovery of particles regardless of the polymer type (n=2 experiments per polymer) (Fig. S1). \u003c/p\u003e\n\u003ch2\u003e2.6. FTIR spectroscopy Sample Analysis\u003c/h2\u003e\n\u003cp\u003eThe 25 \u0026mu;m filters were scanned for particles under a dissecting microscope at 8.6x magnification. The whole filter was examined, and any particles found were imaged (ThorCam Imaging Software V.3.5.1.1). Particles were then transferred to a piece of double-sided tape in a glass petri dish and numbered. These particles were analyzed with a diamond attenuated total reflection (ATR) attachment on the Cary 630 FTIR (Agilent Technologies Inc). Particles were placed individually on the detection area. MicroLabPC software was used to collect the spectra. \u003c/p\u003e\n\u003ch2\u003e2.7. Raman spectroscopy Sample Analysis\u003c/h2\u003e\n\u003cp\u003eThe 1 \u0026mu;m filter was used for Raman analysis. The particles were analyzed with a Renishaw inVia Raman microscope using Wire 3.4 software to collect images and spectra of the particles. Spectra were collected with a 532 nm excitation laser. The filter was scanned at 20x magnification. Eight transects were made in a straight line across the filter covering 8% of the filter (Fig. 2). Particles were imaged prior to spectra collection. If particles were smaller or larger than the 20x field of view, 50x or 5x magnification was used to image the particle.\u003c/p\u003e\n\u003ch2\u003e2.8. Data Validation and Analysis\u003c/h2\u003e\n\u003cp\u003eThe collected spectra from FTIR and Raman spectroscopy were baseline corrected and smoothed prior to identification. OpenSpecy (Cowger et al., 2021) and a custom library database were used for identifying the particles based on their spectra. Pearson\u0026rsquo;s correlation coefficient (Pearson\u0026rsquo;s r) of greater than or equal to 0.8 was used as a statistical cutoff for a good fit between the reference and the particle spectrum (Giani et al., 2023; Zhu et al., 2023). All the plastic particle spectra (Pearson\u0026rsquo;s r \u0026gt; 0.8) were then manually checked to ensure that the spectral peaks were well matched with the reference peaks from both the libraries (Renner et al., 2019). Particles (Pearson\u0026rsquo;s r \u0026gt; 0.8) were not used in the subsequent analysis if they had peaks that either did not match the overall pattern in the reference spectrum or had a low enough signal-to-noise ratio that it was challenging to interpret the true signal. Examples of spectra that were included or excluded in the analysis are shown in Figure 3,\u003c/p\u003e\n\u003cp\u003eSpectral peaks were identified according to commonly reported Raman shifts in the literature. Plastic degradation or weathering peaks were identified in all of the samples. Non-plastic particles were compared to reference spectra for a variety of different materials, including fur, cellulose, cotton, sand, chitin, and plant material. The non-plastic particles were identified by a Pearson\u0026rsquo;s r of 0.8 or greater without manually comparing the spectra matches. \u003c/p\u003e\n\u003ch2\u003e2.9. Statistics\u003c/h2\u003e\n\u003cp\u003eFulton\u0026rsquo;s condition index (K) (Equation 1) was calculated to determine the overall health of the fish (Ricker, 1975). \u003c/p\u003e\n\u003cp\u003eEquation 1: K=(W/TL\u003csup\u003e3\u003c/sup\u003e)* 100; W is the fish weight and TL is the total length.\u003c/p\u003e\n\u003cp\u003eMP abundance and occurrence data were non-normally distributed, so nonparametric analyses were used. To predict the occurrence of MPs in the muscle, a Random Forest model was generated using the R CARET package\u0026rsquo;s leave-one-subject-out train() function (Kuhn, 2008). Fish length, sex and plastic content in the GI tract were used as input variables. Spearman\u0026rsquo;s rank correlation was used to determine the correlation between fish total length and GI tract and muscle MP abundance. Graphpad Prism (10.0.2) was used to calculate the Spearman\u0026rsquo;s rank correlations and to generate the visualizations. Significant correlations were accepted if the p-value of the Spearman\u0026rsquo;s rank correlation was less than 0.05. \u003c/p\u003e\n\u003cp\u003eThe Random Forest analysis used MP occurrence in muscle samples, and the Spearman\u0026rsquo;s rank correlation used the muscle MP abundance. \u003c/p\u003e\n\u003cp\u003eAll concentrations are reported as the number of particles per gram of tissue wet weight. Data from the Raman analysis are based on the whole filter plastic count estimates extrapolated from the 8% of the filter that was analyzed. No corrections were made for the FTIR data since the whole filter was analyzed. \u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003eIn the eighteen fish analyzed, 69 MPs were identified in the GI tract or the muscle. The fish collected from Falmouth generally contained more MPs than the fish collected from Bourne. Given the developing nature of the field, we describe the different metrics used to verify our sample analysis below. In the next section, the differences in MP morphologies are compared between the GI tract and muscle samples. Following that, we examine the impact of fish total length and sex on MP abundance.\u003c/p\u003e\n\u003ch3\u003e3. 1. Methodology Verification\u003c/h3\u003e\n\u003cp\u003eAll encountered particles were analyzed using either Raman or FTIR. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4% (69 particles) were identified as plastic (Table S2). All particles identified as plastic had a Pearson\u0026rsquo;s r correlation of at least 0.82, and an average correlation of 0.91 (Table S3). In Falmouth fish, there were 50 plastic particles in the GI tract samples and nine in the muscle tissue. The Bourne fish had nine plastic particles in the GI tract and only one in the muscle tissue.\u003c/p\u003e \u003cp\u003eIn our procedural blanks, only one particle was identified as plastic (polypropylene). No polypropylene was detected in the fish samples analyzed concurrently with the contaminated procedural blank. Due to the detection of only a single plastic particle out of 11 procedural blanks, no blank correction was performed. Of the 180 particles analyzed with a correlation of at least 0.8, 70 particles were included in the microplastic analysis. Particles not included could be plastic particles that had altered spectra due to particle oxidation or the presence of additives. The analysis we used is highly conservative, due to uncertainty surrounding the 110 particles not included in the analysis.\u003c/p\u003e \u003cp\u003eNumerous plant-based, chitin and or bone particles were detected with FTIR analysis (Fig. S2A \u0026amp; S2B). Fish collected from Bourne had more plant-based particles in their GI tracts than Falmouth fish (Fig. S2A). Some cellulose and cotton particles were also detected in the samples (Fig. S2). Raman spectroscopy analysis detected primarily minerals, metal compounds, and fragments of soot or black pigment (Fig. S2C \u0026amp; S2D).\u003c/p\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Plastic particle identification\u003c/h2\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1. Plastic Concentrations\u003c/h2\u003e \u003cp\u003eMP occurrence varied widely between the water and fish tissue (GI tract and muscle) samples. The water samples had no detected MPs (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). GI tract samples contained MPs more frequently than the muscle samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). Most Falmouth fish contained MPs, with 87.5% of the GI tract samples and 62.5% of muscle samples containing MPs (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). The Bourne sampling site had a lower MP occurrence, with 40.0% of the GI tract samples and 10.0% of muscle samples containing MPs (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA).\u003c/p\u003e \u003cp\u003eMP concentration varied by tissue and sampling site, with the Falmouth GI tract samples containing the largest concentration of plastics (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB). The median concentration of MPs in the GI tract of fish from Falmouth was 83 particles/g w.w. while the muscle samples had a median concentration of only 11 particles/g w.w. tissue. Both the GI tract and muscle samples from Bourne fish had a median concentration of 0 particles/g w.w. with the GI tract having a 2.6x greater range compared to the muscle samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB). Many fish did not contain any MPs (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), leading to large standard deviations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e3.2.2. Plastic Sizes\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAverage Concentration and Size of MPs in fish tissues from Falmouth and Bourne. The mean concentration\u0026thinsp;\u0026plusmn;\u0026thinsp;1 standard deviation is shown. For size characteristics, the medians are shown with range in parentheses.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCollection Site\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eFalmouth\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eBourne\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTissue\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGI Tract\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMuscle\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGI Tract\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMuscle\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMP Occurrence (# MP samples/total sample number)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7/8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5/8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4/10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1/10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eMP Concentration\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e(Particle Count/g w.w.)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e85.5\u0026thinsp;\u0026plusmn;\u0026thinsp;70.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.4\u0026thinsp;\u0026plusmn;\u0026thinsp;12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12.2\u0026thinsp;\u0026plusmn;\u0026thinsp;18.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.69\u0026thinsp;\u0026plusmn;\u0026thinsp;5.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLength (\u0026micro;m)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.8 (2.60\u0026ndash;1291)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.5 (4.26\u0026ndash;28.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24.6 (5.19\u0026ndash;728)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eWidth (\u0026micro;m)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.6 (2.10\u0026ndash;140)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.52 (1.79\u0026ndash;13.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.8 (2.35\u0026ndash;248)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAspect Ratio (Length/Width)\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.41 (0.61\u0026ndash;51.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.13 (0.97\u0026ndash;10.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.21 (1.28\u0026ndash;6.78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe MP size distributions were similar between the two collection sites (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), so the data from the sampling sites were combined to more closely examine how MP characteristics differ between tissues. Particles 2 \u0026micro;m \u0026minus;\u0026thinsp;5 mm in length were analyzed in the collected samples. Length is defined as the longest dimension of the particle in a 2-dimensional plane. The particle lengths ranged from 2.6 \u0026micro;m \u0026minus;\u0026thinsp;1291 \u0026micro;m. The median MP length in the GI tract was 24.7 \u0026micro;m, and the median MP length for the muscle samples was 14.5 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA). MPs in the GI tract had a greater size range of 1289 \u0026micro;m compared to the muscle MP\u0026rsquo;s size range of 23.9 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA); however, for both tissue types most of the particles (81.2%) were smaller than 50 \u0026micro;m in length (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.2.3. Plastic Shape\u003c/h2\u003e \u003cp\u003eThe particle aspect ratio was determined by dividing the length of the particle by the particle width. The particle aspect ratios varied more widely in the GI tract than in the muscle samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB). The median aspect ratios for the GI tract and muscle were approximately 1.6 and 1.9, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003eAn aspect ratio of three or greater was used to define a particle as a fiber (Li et al., \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Any particles with an aspect ratio below three were defined as a fragment. The identified MPs were predominantly fragments (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eC). The GI tract and muscle samples had similar percentages of fragments and fibers. The GI tract particles were 78.6% fragments and 21.4% fibers, and the muscle particles were 80.0% fragments and 20.0% fibers (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eC).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e3.2.4. Polymer Types\u003c/h2\u003e \u003cp\u003eNylon was the major polymer present in the samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Polyethylene was found in the GI tracts collected from both Falmouth and Bourne sites in roughly equivalent percentages (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eA). We rarely found polypropylene and polyurethane in the samples (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eA). The GI tract particle composition consisted of nylon (84.8%), polyethylene (11.9%), polypropylene (1.7%), and polyurethane (1.7%) (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eB). The MPs found in the muscle samples were all nylon (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003eThe full range of both the length and aspect ratio for each particle is shown in Figure S3A. The length of the nylon particles was significantly correlated (r\u0026thinsp;=\u0026thinsp;0.5; p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.001) with aspect ratio (Fig. S3A \u0026amp; S3B; Linear regression R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.74). The length of the polyethylene particles, on the other hand, was not correlated with the aspect ratio (r\u0026thinsp;=\u0026thinsp;0.42; p-value 0.35; Fig. S3B). The polyethylene particles and nylon particles had similar proportions of fragments (Fig. S3C).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.2.5. Plastic Weathering\u003c/h2\u003e \u003cp\u003eIdentified MPs frequently had two spectral peaks (800\u0026ndash;900 and 1600\u0026ndash;1700 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) suggestive of particle oxidation (Fig. S4; Matsui et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Phan et al., \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). An example of a spectrum displaying these oxidation peaks is illustrated in Figure S4A \u0026amp; S4B along with a picture of the particle and its identified chemical structure. Many particles found in both the GI tract and the muscle samples contained both of those peaks, indicating oxidation of the particles (Fig. S4C). Fewer MPs had the additional 1600 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e peak compared to the 800\u0026ndash;900 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e peak (Fig. S4C). It should also be noted that only 10 MPs were detected in the muscle samples, which could skew the reported peak proportions.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Impact of Fish Length on Microplastic Abundance\u003c/h2\u003e \u003cp\u003eMP abundance correlated with fish total length in the muscle and GI tract; however, key differences between the fish from the different sampling sites complicated this analysis. Only female fish were caught at the Falmouth site (8/8 fish), and mostly male fish were caught at the Bourne site (8/10 fish). The fish collected at the Falmouth site were also larger than those collected at the Bourne site (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e7\u003c/span\u003e). These site differences made it challenging to disentangle the impact of sex and fish total length from the different collection sites (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e7\u003c/span\u003e). Fish collected from both sites had equivalent Fulton\u0026rsquo;s condition factors.\u003c/p\u003e \u003cp\u003eAdditionally, the water samples from both sites had MPs below the limit of detection, indicating that MP prevalence is low at both collection sites. Therefore, for the following analyses the information from both collection sites has been combined.\u003c/p\u003e \u003cp\u003eFish total length correlated with MP abundance in both the GI tract (r\u0026thinsp;=\u0026thinsp;0.51; p-value 0.03) and the muscle (r\u0026thinsp;=\u0026thinsp;0.48; p-value 0.04; Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eA \u0026amp; \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eB). Both comparisons showed a moderately positive relationship. GI tract MP abundance did not correlate with muscle MP abundance (r\u0026thinsp;=\u0026thinsp;0.25; p-value 0.31; Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eC). Female fish had a greater MP abundance than male fish in both the GI tract and muscle (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eD). In fact, only female fish had MPs present in the muscle (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003eD). The random forest analysis determined that fish total length was the most important variable for predicting muscle MP occurrence, followed by fish sex and then GI tract MP abundance (Table S4).\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe bioaccumulation potential of environmental MPs is not well understood, in part because MP detection is a developing field with little harmonization amongst methods. This study sought to draw on existing recommendations from the field while expanding on both classification techniques and the detectable size range of MPs. Using this rigorous approach, we compare the characteristics of MPs found in the GI tract and muscle. Of particular focus in the following sections are the small size of detected MPs and the correlation of MP abundance and fish total length. Other factors are also discussed to ensure a thorough characterization of the data for future research to draw upon.\u003c/p\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Importance of Methods in MP Assessment\u003c/h2\u003e \u003cp\u003eThe concentrations and occurrence frequencies of MPs from different field studies are difficult to compare due to the lack of standardized methods across the field. It is unclear how much differences in \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eMP identification approaches\u003c/span\u003e (Abbasi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Akhbarizadeh et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Curtean-Bănăduc et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; My et al., \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Piskuła \u0026amp; Astel, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Qaiser et al., \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ecollection methods\u003c/span\u003e (Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Matupang et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Men\u0026eacute;ndez et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Piskuła \u0026amp; Astel, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sultan et al., \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), and \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003equality control measures\u003c/span\u003e (Esmaeilbeigi et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Kumari et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Nawar et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Piskuła \u0026amp; Astel, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Qaiser et al., \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Raza et al., \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sabilillah et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Widyastuti et al., \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) have influenced these results. These differences highlight the often reported (Provencher et al., \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e2017\u003c/span\u003e, \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) need for harmonized methods of MP analysis and improved methods for detecting smaller MPs.\u003c/p\u003e \u003cp\u003eIn our study, no significant background contamination was seen, with only one MP detected from the procedural blanks. Recovery assessments with 250 \u0026micro;m particles yielded an 80% recovery rate for three different polymers tested. All of the tested polymers were fragments or spheres, so the recovery rate for fibers in this study is unknown. Particles smaller than 250 \u0026micro;m were not tested due to difficulty in small particle manipulation. Protocols to assess the recovery of different sizes and shapes of MPs are essential to increase the reproducibility of these results.\u003c/p\u003e \u003cp\u003eMP sub-sampling was done in this study to reduce the analysis time of each sample; however, the use of sub-sampling can introduce misestimates of MP concentration (Brandt et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Sub-sampling recommendations are still being developed, especially for MPs smaller than 50 \u0026micro;m. Previous recommendations suggest that our results should be representative of MPs present but might not capture MP polymers that occurred rarely in our sampling environment (De Frond et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; El Khatib et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Comparison of MPs in Muscle and GI Tract\u003c/h2\u003e \u003cp\u003eWe predicted that the size of the MPs is the most important parameter for potential bioaccumulation, but we also considered other factors that are known to impact particle uptake, such as particle shape, polymer composition, and degradation status.\u003c/p\u003e \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e \u003ch2\u003e4.2.1. Concentrations of MPs\u003c/h2\u003e \u003cp\u003eWe detected no plastic particles in our water samples using an established method for detecting small MPs in water (Covernton et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Dent et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Green et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Qaiser et al., \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sabilillah et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Despite our water samples having non-detectable levels of MPs, MPs were detected in the sampled fish, indicating MP presence in our sample sites.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMP Concentrations in Fish: A comparison of the average concentrations of MPs found in the GI tract and muscle. Concentrations are shown as the average number of MPs per gram of wet weight\u0026thinsp;\u0026plusmn;\u0026thinsp;1 standard deviation. If a range is present, multiple species were sampled in the study. A dash indicates the tissue was not analyzed. N.D. = not detected\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStudy\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMP Size Limit of Detection\u003c/p\u003e \u003cp\u003e(\u0026micro;m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGI Tract Concentration\u003c/p\u003e \u003cp\u003e(MPs/g W.W.)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMuscle Concentration (MPs/g W.W.)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCurrent Study\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e45\u0026thinsp;\u0026plusmn;\u0026thinsp;60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDi Giacinto et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2023\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u0026ndash;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.14\u0026ndash;0.27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSu et al., \u003cspan citationid=\"CR88\" class=\"CitationRef\"\u003e2019\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1\u0026ndash;8.8\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN.D.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePark et al., \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.42\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSoltani et al., 2023\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u0026ndash;0.47\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWu et al., \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2023\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eBoth collection site and tissue type affected MP occurrence frequencies. MPs occurred more frequently in the GI tract than in the muscle samples. This trend is generally agreed upon in the literature (Jeyasanta et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; My et al., \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Pandey et al., \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) with one study finding the opposite trend (Dent et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe present study\u0026rsquo;s estimated GI tract MP concentration (45 particles/g w.w) is higher than those in other studies (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The muscle samples had a lower MP concentration than the GI tract samples, but the muscle sample concentration was still greater than most of those previously reported (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). A difference in size limits of detection could partly explain this difference, as we were able to detect smaller particles than most previous studies.\u003c/p\u003e \u003cp\u003eThe absorption of MPs into the GI tract epithelium cannot be determined from our results since both GI tract and GI tract contents were digested together. It has previously been shown that GI tract contents contain higher MP concentrations than just the GI tract epithelium (Curtean-Bănăduc et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Rosas et al., \u003cspan citationid=\"CR83\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), suggesting that few particles are absorbed by the epithelium from ingested food; however, uptake is known to be in part size-dependent, and the retention and rate of tissue translocation of the smaller MPs found in our study are unknown.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003e4.2.2. Plastic Sizes\u003c/h2\u003e \u003cp\u003eThe size of MPs found in both the environment and in biota ranges widely throughout the literature. MPs range from 1 \u0026micro;m \u0026minus;\u0026thinsp;5 mm in commonly agreed definitions (Rochman et al., \u003cspan citationid=\"CR81\" class=\"CitationRef\"\u003e2019a\u003c/span\u003e); however, few studies measure the full-size range of these particles. It is common for studies to have minimum size limits of detection that are much higher than the 1 \u0026micro;m theoretical minimum size, or to not report the size limits of detection (Reviewed in Pitt et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). For example, we found that in studies reporting a minimum size detection limit, the median value was 206 \u0026micro;m, with most studies not reporting a minimum size detection limit (Pitt et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). These differences in size detection limits make it challenging to compare the abundance of MP sizes detected in fish tissues, such as the muscle, which is predicted to preferentially accumulate smaller MPs. The current study was able to measure particles 2 \u0026micro;m \u0026minus;\u0026thinsp;5 mm in size.\u003c/p\u003e \u003cp\u003eStudies often find that smaller particles are the most prevalent in the atmosphere (Liao et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), water (Shim et al., \u003cspan citationid=\"CR87\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), and organisms (Valente et al., \u003cspan citationid=\"CR93\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Our study found the GI tract and muscle MP median lengths to be 24.7 \u0026micro;m and 14.5 \u0026micro;m respectively, sizes that are smaller than the most commonly reported minimum size detection limits for biological samples (Amini-Birami et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Collard et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Matluba et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Widyastuti et al., \u003cspan citationid=\"CR95\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Other studies in non-GI tract tissues have found MPs larger than those found in the current study (Abbasi et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Curtean-Bănăduc et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Esmaeilbeigi et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Matias et al., \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; My et al., \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Nawar et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sabilillah et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sultan et al., \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), but the uptake pathway used by these larger particles is unclear, as in some cases, they are above previously established uptake limits (Lusher et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe MPs found in the muscle were both smaller in size and size range than those found in the GI tract, implying a size restriction for particles to enter the muscle. It has been suggested that particle translocation from the GI tract through a mechanism called persorption has an upper size limit of 150 \u0026micro;m (Lusher et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Persorption is the paracellular movement of particles in the desquamation region of epithelial cells (Volkheimer, \u003cspan citationid=\"CR94\" class=\"CitationRef\"\u003e1974\u003c/span\u003e). This mechanism of transport has been previously critiqued as being unlikely and has not been demonstrated since its inception (Hussain et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; O\u0026rsquo;hagan, \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). The actual upper limit of translocation is uncertain, but previous research suggests that only particles smaller than 21 \u0026micro;m are capable of translocating into tissues (Deng et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Lusher et al., \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Jin et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the present study, eight (out of ten) of the MPs detected in muscle were smaller than 21 \u0026micro;m. The maximum size for particles found in the muscle was 28 \u0026micro;m. How these particles reached the muscle is unclear, but some phagocytic cells are 25\u0026ndash;30 \u0026micro;m in size and might be capable of engulfing and transporting these particles (Lendeckel et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). GI tract absorption of particles is the most likely route of uptake, as particles larger than 10 \u0026micro;m are unlikely to be internalized from the lungs or gills (Prata, \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). We suggest that the MPs detected in the muscle were moved there following phagocytic cell engulfment from the GI tract.\u003c/p\u003e \u003cp\u003eThe present study is the first to look for the full-size range of MPs in non-GI tract tissues without significant contamination issues. Previous environmental studies with size detection limits lower than 21 \u0026micro;m either did not look for larger MPs (Di Giacinto et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Ferrante et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) or had a significant amount of background contamination (Akoueson et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Rasta et al., \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Su et al., \u003cspan citationid=\"CR88\" class=\"CitationRef\"\u003e2019\u003c/span\u003e); however, it is clear from previous studies that particle translocation is governed by factors other than size, as particles theoretically small enough to translocate have not moved through the intestinal wall (Kim et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Pyl et al., \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section3\"\u003e \u003ch2\u003e4.2.3. Particle Shape\u003c/h2\u003e \u003cp\u003eThe higher proportion of fragments, versus fibers, in our samples compared to previous studies could be due to the smaller size of MPs detected in our study versus these earlier studies (Akoueson et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Mai et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Matias et al., \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Matupang et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Men\u0026eacute;ndez et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Piskuła \u0026amp; Astel, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; S\u0026aacute;nchez-Guerrero-Hern\u0026aacute;ndez et al., \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Previously, fibers have tended to predominate in larger size fractions of MPs, while fragments make up the majority of particles\u0026thinsp;\u0026lt;\u0026thinsp;100 \u0026micro;m (Liao et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Piskuła \u0026amp; Astel, \u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). On the other hand, some studies that quantified particles down to 20 \u0026micro;m in size have detected primarily fibers, emphasizing that size is not necessarily the major predicting factor for determining particle shape (Kumari et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Pandey et al., \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Park et al., \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sabilillah et al., \u003cspan citationid=\"CR84\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR96\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Zhu et al., \u003cspan citationid=\"CR97\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePreviously, it has been speculated that fibers are more likely to translocate or be internalized by cells compared to other MP shapes (Ramsperger et al., \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2023\u003c/span\u003e); however, our study contradicts that finding as fibers were not found at a higher frequency in muscle.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section3\"\u003e \u003ch2\u003e4.2.4. Polymer Types\u003c/h2\u003e \u003cp\u003eNylon was the predominant polymer (80\u0026ndash;88%) in the GI tract samples. While nylon has occasionally been reported as the major polymer in samples spanning a large range of trophic levels (Amini-Birami et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Covernton et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Nawar et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; S\u0026aacute;nchez-Guerrero-Hern\u0026aacute;ndez et al., \u003cspan citationid=\"CR85\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), polypropylene and polyethylene are usually the most common polymers reported in marine organisms (Dent et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Di Giacinto et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Giani et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Kor et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Mahu et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Matluba et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Park et al., \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Zhu et al., \u003cspan citationid=\"CR97\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Polypropylene and polyethylene are less dense than water, and so species found near the surface of the water could be more likely to encounter these polymer types. Nylon, on the other hand, is slightly denser than seawater, and so would be more likely to sink to the benthic and benthopelagic environment where killifish dwell.\u003c/p\u003e \u003cp\u003eIn contrast to the GI tracts, nylon was the only polymer found in the muscle samples. One other study has found nylon at an increased proportion in muscle compared to the GI tract (Sultan et al., \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) with other studies seeing no difference (Men\u0026eacute;ndez et al., \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Our results suggest that nylon more readily penetrates into muscle than polyethylene.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003e4.3. Implications for MP Bioaccumulation\u003c/h2\u003e \u003cp\u003eWe did not calculate a bioaccumulation factor from our results due to a lack of information regarding the water and sediment concentrations of MPs at the collection sites. Our results suggest that few MPs are ultimately internalized to the muscle. MP deposition in the muscle was potentially impacted by the sex and total length of the fish.\u003c/p\u003e \u003cdiv id=\"Sec29\" class=\"Section3\"\u003e \u003ch2\u003e4.3.1. Relationship between Fish Length and MP Abundance\u003c/h2\u003e \u003cp\u003eThe long-term sequestration of larger MPs (\u0026gt;\u0026thinsp;100 \u0026micro;m) has previously been shown to be unlikely (Covernton et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Giani et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Matias et al., \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Valente et al., \u003cspan citationid=\"CR93\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; reviewed in Pitt et al., \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). The bioaccumulation potential, especially for smaller MPs (\u0026lt;\u0026thinsp;100 \u0026micro;m), has remained unclear, largely due to a lack of information about the distribution and abundance of MPs in non-GI tract tissues; however, our study has started to address this knowledge gap.\u003c/p\u003e \u003cp\u003eA positive relationship was observed between fish length and the MP abundance in the GI tract. This finding agrees with the majority of studies (Esmaeilbeigi et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Jeyasanta et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Mai et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Makhdoumi et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Matupang et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) despite some contradictory evidence (Dent et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Kor et al., \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Park et al., \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Sultan et al., \u003cspan citationid=\"CR90\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). It has been suggested that one reason studies report a positive correlation could be that as fish grow, they can ingest a wider size range of MPs and, consequently, are exposed to more MPs in the environment (Bhattacharjee et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Larger fish also have increased dietary needs, and so might ingest more prey, thus increasing their incidental MP ingestion.\u003c/p\u003e \u003cp\u003eA positive relationship was also seen between fish length and MP abundance and occurrence in the muscle. This contrasts with most of the existing literature, which did not see this trend for non-GI tract tissues (Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Makhdoumi et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The lowest reported MP size for some of these studies was approximately 63 \u0026micro;m, which is 31.5 times larger than our lowest reported MP size (Guilhermino et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). It seems likely that MP size influences trends seen regarding fish length. Our results suggest that small MPs, which are often not quantified, are the primary MPs to be found in tissues like the muscle. Killifish increase in length as they age (Abraham, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1985\u003c/span\u003e), so the correlation between fish total length and muscle MP abundance also could be indicative of bioaccumulation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec30\" class=\"Section3\"\u003e \u003ch2\u003e4.3.2. Relationship between MP Abundance in the GI Tract and the Muscle\u003c/h2\u003e \u003cp\u003eThere was no observed relationship between the abundance of MPs in the GI tract and in the muscle. This finding agrees with the majority of previous studies (Arafat et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Gedik et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Raza et al., \u003cspan citationid=\"CR77\" class=\"CitationRef\"\u003e2023\u003c/span\u003e) with a few conflicting reports (McIlwraith et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Nawar et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Generally, this suggests that the MP residence times differ between these tissues, and therefore one tissue cannot be used to predict the content of another. GI tract residence time is short, with previous studies showing rapid elimination of larger MPs (\u0026gt;\u0026thinsp;250 \u0026micro;m) in killifish (Ohkubo et al., \u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Given the short residence time of MP in the GI tract and the lack of correlation between GI tract and muscle MP abundance, bioaccumulation assessments should not include GI tract data when considering the long-term sequestration potential of MPs.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec31\" class=\"Section3\"\u003e \u003ch2\u003e4.3.3. Other Factors\u003c/h2\u003e \u003cp\u003eThere were several differences between the sites that potentially contributed to the different patterns in MP abundance that we saw including: proximity to a residential area, connection to the ocean, differences in recent weather patterns, and differences in the characteristics of the collected fish; however, the MP water concentrations were not detectable from both collection sites, indicating similar low contamination levels.\u003c/p\u003e \u003cp\u003eOnly female fish had MPs in muscle samples, and they also had greater GI tract MP abundance. This finding could be confounded by several biases, such as the collected females being predominantly from the Falmouth site and that female fish are larger than male fish; however, a couple of other studies have observed the same trend (Esmaeilbeigi et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Matupang et al., \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Overall, relatively few studies have compared male and female fish in terms of the MP content of GI tract and tissues. In the future, more research is needed to investigate the origins of this trend.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec32\" class=\"Section2\"\u003e \u003ch2\u003e4.4. Conclusions\u003c/h2\u003e \u003cp\u003eThere continues to be a dearth of information regarding the distribution of smaller MPs to non-GI tract tissues. This study only detected smaller MPs in the muscle tissues, suggesting a potential upper limit on the sizes of MPs in muscle tissue. This MP abundance was positively correlated with fish total length, indicating that the smaller MPs detected in this study might bioaccumulate. Future studies should focus MP quantification efforts on small MPs in non-GI tract tissues to further investigate this trend.\u003c/p\u003e \u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eMPs = Microplastics\u003c/p\u003e\n\u003cp\u003eGI = Gastrointestinal\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFTIR = Fourier-transform infrared spectroscopy\u003c/p\u003e\n\u003cp\u003ePVC = Polyvinyl chloride\u003c/p\u003e\n\u003cp\u003ePET = Polyethylene terephthalate\u003c/p\u003e\n\u003cp\u003ePE = Polyethylene\u003c/p\u003e\n\u003cp\u003eATR = Attenuated total reflection\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e5.1 Availability of Data and Materials\u003c/p\u003e\n\u003cp\u003eThe data supporting the findings of this study are available within the paper and its supplementary material and data files. Raw data files (Raman and FTIR spectra) are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e5.2 Competing Interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e5.3 Funding\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was supported in part by Woods Hole Sea Grant (Award No. NA18OAR4170104, project R/P\u0026ndash;89) to M.E.H., N.A., and J.A.P. and by an NSF Graduate Research Fellowship to J.A.P. Additional support was provided by Woods Hole Sea Grant (Award No. NA18OAR4170104, project R/O-59 to S.M.G.) and by the Woods Hole Center for Oceans and Human Health (NIH/NIEHS grant P01ES028938 and NSF grant OCE-1840381 to M.E.H. and N.A.).\u003c/p\u003e\n\u003cp\u003e5.4 Authors\u0026apos; Contributions\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eJAP:\u003c/strong\u003e Conceptualization, Formal analysis, Funding acquisition, Methodology, Visualization, Investigation, Writing - original draft, Writing - review \u0026amp; editing. \u003cstrong\u003eSMG:\u003c/strong\u003e Methodology, Software, Funding acquisition, Resources, Writing \u0026ndash; Review \u0026amp; Editing; \u003cstrong\u003eSY:\u003c/strong\u003e Methodology, Software, Writing \u0026ndash; Review \u0026amp; Editing; \u003cstrong\u003eAPMM:\u003c/strong\u003e Methodology, Resources, Writing \u0026ndash; Review \u0026amp; Editing; \u003cstrong\u003eMEH:\u003c/strong\u003e Conceptualization, Funding acquisition, Methodology, Supervision, Writing - review \u0026amp; editing; \u003cstrong\u003eNA:\u003c/strong\u003e Conceptualization, Funding acquisition, Methodology, Resources, Supervision, Writing - review \u0026amp; editing\u003c/p\u003e\n\u003cp\u003e5.5 Ethics approval\u003c/p\u003e\n\u003cp\u003eAll procedures performed in the study were in accordance with the ethical principles described in the Guide for the Care and Use of Laboratory Animals (U.S. National Research Council, Eighth Edition, 2011).\u0026nbsp;Euthanasia was performed according to the American Veterinary Medical Association (AVMA) Guidelines for the Euthanasia of Animals (2013 Edition). The research protocol was approved by the Institutional Animal Care and Use Committee (IACUC) of the Woods Hole Oceanographic Institution (Assurance D16-00381 from the\u0026nbsp;Office of Laboratory Animal Welfare (OLAW) at\u0026nbsp;the U.S. National Institutes of Health).\u003c/p\u003e\n\u003cp\u003e5.6 Consent to publish\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e5.7 Consent to participate\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e5.8 Acknowledgments\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbbasi, S., Soltani, N., Keshavarzi, B., Moore, F., Turner, A., \u0026amp; Hassanaghaei, M. (2018). Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf. \u003cem\u003eChemosphere\u003c/em\u003e, \u003cem\u003e205\u003c/em\u003e, 80\u0026ndash;87. https://doi.org/10.1016/J.CHEMOSPHERE.2018.04.076\u003c/li\u003e\n\u003cli\u003eAbraham, B. J. (1985). \u003cem\u003eSpecies Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). MUMMICHOG AND STRIPED KILLIFISH.\u003c/em\u003e\u003c/li\u003e\n\u003cli\u003eAkhbarizadeh, R., Moore, F., \u0026amp; Keshavarzi, B. (2018). Investigating a probable relationship between microplastics and potentially toxic elements in fish muscles from northeast of Persian Gulf. \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e232\u003c/em\u003e, 154\u0026ndash;163. https://doi.org/10.1016/J.ENVPOL.2017.09.028\u003c/li\u003e\n\u003cli\u003eAkoueson, F., Sheldon, L. M., Danopoulos, E., Morris, S., Hotten, J., Chapman, E., Li, J., \u0026amp; Rotchell, J. M. (2020). A preliminary analysis of microplastics in edible versus non-edible tissues from seafood samples. \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e263\u003c/em\u003e, 114452. https://doi.org/10.1016/J.ENVPOL.2020.114452\u003c/li\u003e\n\u003cli\u003eAllen, E. A., Fell, P. E., Peck, M. A., Gieg, J. A., Guthke, C. R., \u0026amp; Newkirk, M. D. (1994). Gut contents of common mummichogs, Fundulus heteroclitus L., in a restored impounded marsh and in natural reference marshes. \u003cem\u003eEstuaries\u003c/em\u003e, \u003cem\u003e17\u003c/em\u003e(2), 462\u0026ndash;471. https://doi.org/10.2307\u003c/li\u003e\n\u003cli\u003eAmini-Birami, F., Keshavarzi, B., Esmaeili, H. R., Moore, F., Busquets, R., Saemi-Komsari, M., Zarei, M., \u0026amp; Zarandian, A. (2023). Microplastics in aquatic species of Anzali wetland: An important freshwater biodiversity hotspot in Iran. \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e330\u003c/em\u003e, 121762. https://doi.org/10.1016/J.ENVPOL.2023.121762\u003c/li\u003e\n\u003cli\u003eArafat, S. T., Tanoiri, H., Yokota, M., Nakano, H., Arakawa, H., Terahara, T., \u0026amp; Kobayashi, T. (2023). Microplastic pollution in the gastrointestinal tract of giant river catfish Sperata seenghala (Sykes, 1839) from the Meghna River, Bangladesh. \u003cem\u003eEnvironmental Science and Pollution Research\u003c/em\u003e, \u003cem\u003e1\u003c/em\u003e, 1\u0026ndash;11. https://doi.org/10.1007/S11356-023-28750-Z/FIGURES/4\u003c/li\u003e\n\u003cli\u003eBeier, R., \u0026amp; Gebert, A. (1998). Kinetics of particle uptake in the domes of Peyer\u0026rsquo;s patches. \u003cem\u003eAmerican Journal of Physiology - Gastrointestinal and Liver Physiology\u003c/em\u003e, \u003cem\u003e275\u003c/em\u003e(1 38-1). https://doi.org/10.1152/AJPGI.1998.275.1.G130\u003c/li\u003e\n\u003cli\u003eBhattacharjee, Sh., Mandal, B., Das, R., Bhattacharyya, S., Chaudhuri, P., \u0026amp; Mukherjee, A. (2023). Microplastics in gastro-intestinal tract of estuarine fish from the mangrove ecosystem of Indian Sundarbans. \u003cem\u003eIranian Journal of Fisheries Sciences\u003c/em\u003e, \u003cem\u003e22\u003c/em\u003e(2), 317\u0026ndash;338. https://doi.org/10.22092/IJFS.2023.129046\u003c/li\u003e\n\u003cli\u003eBrandt, J., Fischer, F., Kanaki, E., Enders, K., Labrenz, M., \u0026amp; Fischer, D. (2021). Assessment of Subsampling Strategies in Microspectroscopy of Environmental Microplastic Samples. \u003cem\u003eFrontiers in Environmental Science\u003c/em\u003e, \u003cem\u003e8\u003c/em\u003e, 288. https://doi.org/10.3389/FENVS.2020.579676\u003c/li\u003e\n\u003cli\u003eCarr, K. E., Hazzard, R. A., Reid, S., \u0026amp; Hodges, G. M. (1996). The effect of size on uptake of orally administered latex microparticles in the small intestine and transport to mesenteric lymph nodes. \u003cem\u003ePharmaceutical Research\u003c/em\u003e, \u003cem\u003e13\u003c/em\u003e(8), 1205\u0026ndash;1209. https://doi.org/10.1023\u003c/li\u003e\n\u003cli\u003eCollard, F., Gilbert, B., Comp\u0026egrave;re, P., Eppe, G., Das, K., Jauniaux, T., \u0026amp; Parmentier, E. (2017). Microplastics in livers of European anchovies (Engraulis encrasicolus, L.). \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e229\u003c/em\u003e, 1000\u0026ndash;1005. https://doi.org/10.1016/J.ENVPOL.2017.07.089\u003c/li\u003e\n\u003cli\u003eColombo, C. V., Fern\u0026aacute;ndez-Severini, M. D., Forero-L\u0026oacute;pez, A. D., Ardusso, M. G., Rimondino, G. N., Malanca, F. E., \u0026amp; Buzzi, N. S. (2023). Microplastics in commercial seafood: Pleoticus muelleri as a case study in an estuarine environment highly affected by human pressure (Southwestern Atlantic). \u003cem\u003eEnvironmental Research\u003c/em\u003e, \u003cem\u003e216\u003c/em\u003e, 114738. https://doi.org/10.1016/J.ENVRES.2022.114738\u003c/li\u003e\n\u003cli\u003eCovernton, G. A., Cox, K. D., Fleming, W. L., Buirs, B. M., Davies, H. L., Juanes, F., Dudas, S. E., \u0026amp; Dower, J. F. (2022). Large size (\u0026gt;100-\u0026mu;m) microplastics are not biomagnifying in coastal marine food webs of British Columbia, Canada. \u003cem\u003eEcological Applications\u003c/em\u003e, \u003cem\u003e32\u003c/em\u003e(7), e2654. https://doi.org/10.1002/EAP.2654\u003c/li\u003e\n\u003cli\u003eCovernton, G. A., Pearce, C. M., Gurney-Smith, H. J., Chastain, S. G., Ross, P. S., Dower, J. F., \u0026amp; Dudas, S. E. (2019). Size and shape matter: A preliminary analysis of microplastic sampling technique in seawater studies with implications for ecological risk assessment. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e667\u003c/em\u003e, 124\u0026ndash;132. https://doi.org/10.1016/J.SCITOTENV.2019.02.346\u003c/li\u003e\n\u003cli\u003eCowger, W., Steinmetz, Z., Gray, A., Munno, K., Lynch, J., Hapich, H., Primpke, S., De Frond, H., Rochman, C., \u0026amp; Herodotou, O. (2021). Microplastic Spectral Classification Needs an Open Source Community: Open Specy to the Rescue! \u003cem\u003eAnalytical Chemistry\u003c/em\u003e, \u003cem\u003e93\u003c/em\u003e(21), 7543\u0026ndash;7548. https://doi.org/10.1021/ACS.ANALCHEM.1C00123/SUPPL_FILE/AC1C00123_SI_005.ZIP\u003c/li\u003e\n\u003cli\u003eCurtean-Bănăduc, A., Mihuţ, C., Burcea, A., McCall, G. S., Matei, C., \u0026amp; Bănăduc, D. (2023). Screening for Microplastic Uptake in an Urbanized Freshwater Ecosystem: Chondrostoma nasus (Linnaeus, 1758) Case Study. \u003cem\u003eWater 2023, Vol. 15, Page 1578\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(8), 1578. https://doi.org/10.3390/W15081578\u003c/li\u003e\n\u003cli\u003eDe Frond, H., O\u0026rsquo;Brien, A. M., \u0026amp; Rochman, C. M. (2023). Representative subsampling methods for the chemical identification of microplastic particles in environmental samples. \u003cem\u003eChemosphere\u003c/em\u003e, \u003cem\u003e310\u003c/em\u003e, 136772. https://doi.org/10.1016/J.CHEMOSPHERE.2022.136772\u003c/li\u003e\n\u003cli\u003eDeng, Y., Zhang, Y., Lemos, B., \u0026amp; Ren, H. (2017). Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure. \u003cem\u003eScientific Reports 2017 7:1\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e(1), 1\u0026ndash;10. https://doi.org/10.1038/srep46687\u003c/li\u003e\n\u003cli\u003eDent, A. R., Chadwick, D. D. A., Eagle, L. J. B., Gould, A. N., Harwood, M., Sayer, C. D., \u0026amp; Rose, N. L. (2023). Microplastic burden in invasive signal crayfish (Pacifastacus leniusculus) increases along a stream urbanization gradient. \u003cem\u003eEcology and Evolution\u003c/em\u003e, \u003cem\u003e13\u003c/em\u003e(5), e10041. https://doi.org/10.1002/ECE3.10041\u003c/li\u003e\n\u003cli\u003eDi Giacinto, F., Di Renzo, L., Mascilongo, G., Notarstefano, V., Gioacchini, G., Giorgini, E., Bogdanović, T., Petričević, S., Liste\u0026scaron;, E., Brkljača, M., Conti, F., Profico, C., Zambuchini, B., Di Francesco, G., Giansante, C., Diletti, G., Ferri, N., \u0026amp; Berti, M. (2023). Detection of microplastics, polymers and additives in edible muscle of swordfish (Xiphias gladius) and bluefin tuna (Thunnus thynnus) caught in the Mediterranean Sea. \u003cem\u003eJournal of Sea Research\u003c/em\u003e, \u003cem\u003e192\u003c/em\u003e, 102359. https://doi.org/10.1016/J.SEARES.2023.102359\u003c/li\u003e\n\u003cli\u003eEl Khatib, D., Langknecht, T. D., Cashman, M. A., Reiss, M., Somers, K., Allen, H., Ho, K. T., \u0026amp; Burgess, R. M. (2023). Assessment of filter subsampling and extrapolation for quantifying microplastics in environmental samples using Raman spectroscopy. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e192\u003c/em\u003e, 115073. https://doi.org/10.1016/J.MARPOLBUL.2023.115073\u003c/li\u003e\n\u003cli\u003eEnders, K., Lenz, R., Stedmon, C. A., \u0026amp; Nielsen, T. G. (2015). Abundance, size and polymer composition of marine microplastics \u0026ge; 10 \u0026mu;m in the Atlantic Ocean and their modelled vertical distribution. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e100\u003c/em\u003e(1), 70\u0026ndash;81. https://doi.org/10.1016/J.MARPOLBUL.2015.09.027\u003c/li\u003e\n\u003cli\u003eErni-Cassola, G., Gibson, M. I., Thompson, R. C., \u0026amp; Christie-Oleza, J. A. (2017). Lost, but Found with Nile Red: A Novel Method for Detecting and Quantifying Small Microplastics (1 mm to 20 \u0026mu;m) in Environmental Samples. \u003cem\u003eEnvironmental Science and Technology\u003c/em\u003e, \u003cem\u003e51\u003c/em\u003e(23), 13641\u0026ndash;13648. https://doi.org/10.1021/ACS.EST.7B04512/SUPPL_FILE/ES7B04512_SI_001.PDF\u003c/li\u003e\n\u003cli\u003eEsmaeilbeigi, M., Kazemi, A., Gholizadeh, M., \u0026amp; Rezaeiyeh, R. D. (2023). Microplastics and heavy metals contamination in Atropus atropos and associated health risk assessment in the northwest of the Persian Gulf, Iran. \u003cem\u003eRegional Studies in Marine Science\u003c/em\u003e, \u003cem\u003e57\u003c/em\u003e, 102750. https://doi.org/10.1016/J.RSMA.2022.102750\u003c/li\u003e\n\u003cli\u003eFerrante, M., Pietro, Z., Allegui, C., Maria, F., Antonio, C., Pulvirenti, E., Favara, C., Chiara, C., Grasso, A., Omayma, M., Gea, O. C., \u0026amp; Banni, M. (2022). Microplastics in fillets of Mediterranean seafood. A risk assessment study. \u003cem\u003eEnvironmental Research\u003c/em\u003e, \u003cem\u003e204\u003c/em\u003e, 112247. https://doi.org/10.1016/J.ENVRES.2021.112247\u003c/li\u003e\n\u003cli\u003eGedik, K., Eryaşar, A. R., Emanet, M., Şahin, C., \u0026amp; Ceylan, Y. (2023). Monthly microplastics change in European anchovy\u0026rsquo;s (Engraulis encrasicolus) gastrointestinal tract in the Black Sea. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e194\u003c/em\u003e, 115303. https://doi.org/10.1016/J.MARPOLBUL.2023.115303\u003c/li\u003e\n\u003cli\u003eGiani, D., Andolina, C., Baini, M., Panti, C., Sciandra, M., Vizzini, S., \u0026amp; Fossi, M. C. (2023). Trophic niche influences ingestion of micro- and mesoplastics in pelagic and demersal fish from the Western Mediterranean Sea. \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e328\u003c/em\u003e, 121632. https://doi.org/10.1016/J.ENVPOL.2023.121632\u003c/li\u003e\n\u003cli\u003eGouin, T. (2020). Toward an Improved Understanding of the Ingestion and Trophic Transfer of Microplastic Particles: Critical Review and Implications for Future Research. \u003cem\u003eEnvironmental Toxicology and Chemistry\u003c/em\u003e, \u003cem\u003e39\u003c/em\u003e(6), 1119\u0026ndash;1137. https://doi.org/10.1002/ETC.4718\u003c/li\u003e\n\u003cli\u003eGreen, D. S., Kregting, L., Boots, B., Blockley, D. J., Brickle, P., da Costa, M., \u0026amp; Crowley, Q. (2018). A comparison of sampling methods for seawater microplastics and a first report of the microplastic litter in coastal waters of Ascension and Falkland Islands. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e137\u003c/em\u003e, 695\u0026ndash;701. https://doi.org/10.1016/J.MARPOLBUL.2018.11.004\u003c/li\u003e\n\u003cli\u003eGuilhermino, L., Martins, A., Lopes, C., Raimundo, J., Vieira, L. R., Barboza, L. G. A., Costa, J., Antunes, C., Caetano, M., \u0026amp; Vale, C. (2021). Microplastics in fishes from an estuary (Minho River) ending into the NE Atlantic Ocean. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e173\u003c/em\u003e, 113008. https://doi.org/10.1016/J.MARPOLBUL.2021.113008\u003c/li\u003e\n\u003cli\u003eGulizia, A. M., Brodie, E., Daumuller, R., Bloom, S. B., Corbett, T., Santana, M. M. F., Motti, C. A., Vamvounis, G., Gulizia, A. M., Brodie, E., Daumuller, R., Bloom, S. B., Corbett, T., Santana, M. M. F., Vamvounis, G., \u0026amp; Motti, C. A. (2022). Evaluating the Effect of Chemical Digestion Treatments on Polystyrene Microplastics: Recommended Updates to Chemical Digestion Protocols. \u003cem\u003eMacromolecular Chemistry and Physics\u003c/em\u003e, \u003cem\u003e223\u003c/em\u003e(13), 2100485. https://doi.org/10.1002/MACP.202100485\u003c/li\u003e\n\u003cli\u003eHermsen, E., Mintenig, S. M., Besseling, E., \u0026amp; Koelmans, A. A. (2018). Quality Criteria for the Analysis of Microplastic in Biota Samples: A Critical Review. \u003cem\u003eEnvironmental Science and Technology\u003c/em\u003e, \u003cem\u003e52\u003c/em\u003e(18), 10230\u0026ndash;10240. https://doi.org/10.1021/ACS.EST.8B01611\u003c/li\u003e\n\u003cli\u003eHuang, T., Zhang, W., Lin, T., Liu, S., Sun, Z., Liu, F., Yuan, Y., Xiang, X., Kuang, H., Yang, B., \u0026amp; Zhang, D. (2022). Maternal exposure to polystyrene nanoplastics during gestation and lactation induces hepatic and testicular toxicity in male mouse offspring. \u003cem\u003eFood and Chemical Toxicology\u003c/em\u003e, \u003cem\u003e160\u003c/em\u003e, 112803. https://doi.org/10.1016/J.FCT.2021.112803\u003c/li\u003e\n\u003cli\u003eHussain, N., Jaitley, V., \u0026amp; Florence, A. T. (2001). Recent advances in the understanding of uptake of microparticulates across the gastrointestinal lymphatics. \u003cem\u003eAdvanced Drug Delivery Reviews\u003c/em\u003e, \u003cem\u003e50\u003c/em\u003e(1\u0026ndash;2), 107\u0026ndash;142. https://doi.org/10.1016/S0169-409X(01)00152-1\u003c/li\u003e\n\u003cli\u003eJeyasanta, K. I., Laju, R. L., Patterson, J., Jayanthi, M., Bilgi, D. S., Sathish, N., \u0026amp; Edward, J. K. P. (2023). Microplastic pollution and its implicated risks in the estuarine environment of Tamil Nadu, India. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e861\u003c/em\u003e, 160572. https://doi.org/10.1016/J.SCITOTENV.2022.160572\u003c/li\u003e\n\u003cli\u003eJin, H., Ma, T., Sha, X., Liu, Z., Zhou, Y., Meng, X., Chen, Y., Han, X., \u0026amp; Ding, J. (2021). Polystyrene microplastics induced male reproductive toxicity in mice. \u003cem\u003eJournal of Hazardous Materials\u003c/em\u003e, \u003cem\u003e401\u003c/em\u003e, 123430. https://doi.org/10.1016/J.JHAZMAT.2020.123430\u003c/li\u003e\n\u003cli\u003eKim, J., Poirier, D. G., Helm, P. A., Bayoumi, M., \u0026amp; Rochman, C. M. (2020). No evidence of spherical microplastics (10\u0026ndash;300 \u0026mu;m) translocation in adult rainbow trout (Oncorhynchus mykiss) after a two-week dietary exposure. \u003cem\u003ePLOS ONE\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(9), e0239128. https://doi.org/10.1371/JOURNAL.PONE.0239128\u003c/li\u003e\n\u003cli\u003eKoelmans, A. A., Mohamed Nor, N. H., Hermsen, E., Kooi, M., Mintenig, S. M., \u0026amp; De France, J. (2019). Microplastics in freshwaters and drinking water: Critical review and assessment of data quality. \u003cem\u003eWater Research\u003c/em\u003e, \u003cem\u003e155\u003c/em\u003e, 410\u0026ndash;422. https://doi.org/10.1016/J.WATRES.2019.02.054\u003c/li\u003e\n\u003cli\u003eKor, K., Jannat, B., Ershadifar, H., \u0026amp; Ghazilou, A. (2023). Microplastic occurrence in finfish and shellfish from the mangroves of the northern Gulf of Oman. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e189\u003c/em\u003e, 114788. https://doi.org/10.1016/J.MARPOLBUL.2023.114788\u003c/li\u003e\n\u003cli\u003eKuhn, M. (2008). Building Predictive Models in R Using the caret Package. \u003cem\u003eJournal of Statistical Software\u003c/em\u003e, \u003cem\u003e28\u003c/em\u003e(5), 1\u0026ndash;26. https://doi.org/10.18637/JSS.V028.I05\u003c/li\u003e\n\u003cli\u003eKumari, N., Yadav, D. K., Yasha, Khan, P. K., \u0026amp; Kumar, R. (2023). Occurrence of plastics and their characterization in wild caught fish species (Labeo rohita, Wallago attu and Mystus tengara) of River Ganga (India) compared to a commercially cultured species (L. rohita). \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e334\u003c/em\u003e, 122141. https://doi.org/10.1016/J.ENVPOL.2023.122141\u003c/li\u003e\n\u003cli\u003eLebreton, L., Egger, M., \u0026amp; Slat, B. (2019). A global mass budget for positively buoyant macroplastic debris in the ocean. \u003cem\u003eScientific Reports 2019 9:1\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e(1), 1\u0026ndash;10. https://doi.org/10.1038/s41598-019-49413-5\u003c/li\u003e\n\u003cli\u003eLendeckel, U., Venz, S., \u0026amp; Wolke, C. (2022). Macrophages: shapes and functions. \u003cem\u003eChemTexts\u003c/em\u003e, \u003cem\u003e8\u003c/em\u003e(2), 1\u0026ndash;12. https://doi.org/10.1007/S40828-022-00163-4/TABLES/3\u003c/li\u003e\n\u003cli\u003eLenz, R., Enders, K., Stedmon, C. A., MacKenzie, D. M. A., \u0026amp; Nielsen, T. G. (2015). A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e100\u003c/em\u003e(1), 82\u0026ndash;91. https://doi.org/10.1016/J.MARPOLBUL.2015.09.026\u003c/li\u003e\n\u003cli\u003eLi, Y., Shao, L., Wang, W., Zhang, M., Feng, X., Li, W., \u0026amp; Zhang, D. (2020). Airborne fiber particles: Types, size and concentration observed in Beijing. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e705\u003c/em\u003e, 135967. https://doi.org/10.1016/J.SCITOTENV.2019.135967\u003c/li\u003e\n\u003cli\u003eLiao, Z., Ji, X., Ma, Y., Lv, B., Huang, W., Zhu, X., Fang, M., Wang, Q., Wang, X., Dahlgren, R., \u0026amp; Shang, X. (2021). Airborne microplastics in indoor and outdoor environments of a coastal city in Eastern China. \u003cem\u003eJournal of Hazardous Materials\u003c/em\u003e, \u003cem\u003e417\u003c/em\u003e, 126007. https://doi.org/10.1016/J.JHAZMAT.2021.126007\u003c/li\u003e\n\u003cli\u003eL\u0026ouml;der, M. G. J., Imhof, H. K., Ladehoff, M., L\u0026ouml;schel, L. A., Lorenz, C., Mintenig, S., Piehl, S., Primpke, S., Schrank, I., Laforsch, C., \u0026amp; Gerdts, G. (2017). Enzymatic Purification of Microplastics in Environmental Samples. \u003cem\u003eEnvironmental Science and Technology\u003c/em\u003e, \u003cem\u003e51\u003c/em\u003e(24), 14283\u0026ndash;14292. https://doi.org/10.1021/ACS.EST.7B03055\u003c/li\u003e\n\u003cli\u003eLusher, A., Hollman, P., \u0026amp; Mendoza-Hill, J. (2017). Microplastics in fisheries and aquaculture: status of knowledge on their occurrence and implications for aquatic organisms and food safety. FAO.\u003c/li\u003e\n\u003cli\u003eMahu, E., Datsomor, W. G., Folorunsho, R., Fisayo, J., Crane, R., Marchant, R., Montford, J., Boateng, M. C., Edusei Oti, M., Oguguah, M. N., \u0026amp; Gordon, C. (2023). Human health risk and food safety implications of microplastic consumption by fish from coastal waters of the eastern equatorial Atlantic Ocean. \u003cem\u003eFood Control\u003c/em\u003e, \u003cem\u003e145\u003c/em\u003e, 109503. https://doi.org/10.1016/J.FOODCONT.2022.109503\u003c/li\u003e\n\u003cli\u003eMai, H., Thao Nhi Ngo, T., Thien Nguyen, D., Hoi Bui, V., Duong Dao, T., Thom Dang, T., Manh Do, V., Quoc Viet, H., Giay, C., Noi, H., \u0026amp; Nam, V. (2023). Preliminary assessment of microplastic pollution in commercial freshwater fish species collected from four districts in Bac Ninh province. \u003cem\u003eVietnam Journal of Science and Technology\u003c/em\u003e, \u003cem\u003e61\u003c/em\u003e(4), 629\u0026ndash;639. https://doi.org/10.15625/2525-2518/17926\u003c/li\u003e\n\u003cli\u003eMakhdoumi, P., Hossini, H., Nazmara, Z., Mansouri, K., \u0026amp; Pirsaheb, M. (2021). Occurrence and exposure analysis of microplastic in the gut and muscle tissue of riverine fish in Kermanshah province of Iran. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e173\u003c/em\u003e, 112915. https://doi.org/10.1016/J.MARPOLBUL.2021.112915\u003c/li\u003e\n\u003cli\u003eMatias, R. S., Gomes, S., Barboza, L. G. A., Salazar-Gutierrez, D., Guilhermino, L., \u0026amp; Valente, L. M. P. (2023). Microplastics in water, feed and tissues of European seabass reared in a recirculation aquaculture system (RAS). \u003cem\u003eChemosphere\u003c/em\u003e, \u003cem\u003e335\u003c/em\u003e, 139055. https://doi.org/10.1016/J.CHEMOSPHERE.2023.139055\u003c/li\u003e\n\u003cli\u003eMatluba, M., Ahmed, M. K., Chowdhury, K. M. A., Khan, N., Ashiq, M. A. R., \u0026amp; Islam, M. S. (2023). The pervasiveness of microplastic contamination in the gastrointestinal tract of fish from the western coast of Bangladesh. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e193\u003c/em\u003e, 115145. https://doi.org/10.1016/J.MARPOLBUL.2023.115145\u003c/li\u003e\n\u003cli\u003eMatsui, H., Arrivo, S. M., Valentini, J. J., \u0026amp; Weber, J. N. (2000). Resonance Raman studies of photoinduced decomposition of nylon-6, 6: product identification and mechanistic determination. Macromolecules, 33(15), 5655-5664.\u003c/li\u003e\n\u003cli\u003eMatupang, D. M., Zulkifli, H. I., Arnold, J., Lazim, A. M., Ghaffar, M. A., \u0026amp; Musa, S. M. (2023). Tropical sharks feasting on and swimming through microplastics: First evidence from Malaysia. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e189\u003c/em\u003e, 114762. https://doi.org/10.1016/J.MARPOLBUL.2023.114762\u003c/li\u003e\n\u003cli\u003eMcIlwraith, H. K., Kim, J., Helm, P., Bhavsar, S. P., Metzger, J. S., \u0026amp; Rochman, C. M. (2021). Evidence of Microplastic Translocation in Wild-Caught Fish and Implications for Microplastic Accumulation Dynamics in Food Webs. \u003cem\u003eEnvironmental Science and Technology\u003c/em\u003e, \u003cem\u003e55\u003c/em\u003e(18), 12372\u0026ndash;12382. https://doi.org/10.1021/ACS.EST.1C02922/SUPPL_FILE/ES1C02922_SI_002.XLSX\u003c/li\u003e\n\u003cli\u003eMen\u0026eacute;ndez, D., Blanco-Fernandez, C., Machado-Schiaffino, G., Ardura, A., \u0026amp; Garcia-Vazquez, E. (2023). High microplastics concentration in liver is negatively associated with condition factor in the Benguela hake Merluccius polli. \u003cem\u003eEcotoxicology and Environmental Safety\u003c/em\u003e, \u003cem\u003e262\u003c/em\u003e, 115135. https://doi.org/10.1016/J.ECOENV.2023.115135\u003c/li\u003e\n\u003cli\u003eMy, T. T. A., Dat, N. D., \u0026amp; Hung, N. Q. (2023). Occurrence and Characteristics of Microplastics in Wild and Farmed Shrimps Collected from Cau Hai Lagoon, Central Vietnam. \u003cem\u003eMolecules\u003c/em\u003e, \u003cem\u003e28\u003c/em\u003e(12), 4634. https://doi.org/10.3390/MOLECULES28124634/S1\u003c/li\u003e\n\u003cli\u003eNawar, N., Rahman, M. M., Chowdhury, F. N., Marzia, S., Ali, M. M., Akbor, M. A., Siddique, M. A. B., Khatun, M. A., Shahjalal, M., Huque, R., \u0026amp; Malafaia, G. (2023). Characterization of microplastic pollution in the Pasur river of the Sundarbans ecosystem (Bangladesh) with emphasis on water, sediments, and fish. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e868\u003c/em\u003e, 161704. https://doi.org/10.1016/J.SCITOTENV.2023.161704\u003c/li\u003e\n\u003cli\u003eNordberg, G. F. (2009). Historical perspectives on cadmium toxicology. \u003cem\u003eToxicology and Applied Pharmacology\u003c/em\u003e, \u003cem\u003e238\u003c/em\u003e(3), 192\u0026ndash;200. https://doi.org/10.1016/J.TAAP.2009.03.015\u003c/li\u003e\n\u003cli\u003eO\u0026rsquo;hagan, D. T. (1996). The intestinal uptake of particles and the implications for drug and antigen delivery. \u003cem\u003eJ. Anal\u003c/em\u003e, \u003cem\u003e189\u003c/em\u003e, 477\u0026ndash;482.\u003c/li\u003e\n\u003cli\u003eOhkubo, N., Ito, M., Hano, T., Kono, K., \u0026amp; Mochida, K. (2020). Estimation of the uptake and gut retention of microplastics in juvenile marine fish: Mummichogs (Fundulus heteroclitus) and red seabreams (Pagrus major). \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e160\u003c/em\u003e, 111630. https://doi.org/10.1016/J.MARPOLBUL.2020.111630\u003c/li\u003e\n\u003cli\u003ePandey, N., Verma, R., Patnaik, S., \u0026amp; Anbumani, S. (2023). Abundance, characteristics, and risk assessment of microplastics in indigenous freshwater fishes of India. \u003cem\u003eEnvironmental Research\u003c/em\u003e, \u003cem\u003e218\u003c/em\u003e, 115011. https://doi.org/10.1016/J.ENVRES.2022.115011\u003c/li\u003e\n\u003cli\u003ePark, B., Kim, S. K., Joo, S., Kim, J. S., Jo, K., Song, N. S., Im, J., Lee, H. J., Kim, S. W., Lee, S. Bin, Kim, S., Lee, Y., Kim, B. Y., \u0026amp; Kim, T. W. (2023). Microplastics in large marine animals stranded in the Republic of Korea. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e189\u003c/em\u003e, 114734. https://doi.org/10.1016/J.MARPOLBUL.2023.114734\u003c/li\u003e\n\u003cli\u003ePhan, S., Padilla-Gami\u0026ntilde;o, J. L., \u0026amp; Luscombe, C. K. (2022). The effect of weathering environments on microplastic chemical identification with Raman and IR spectroscopy: Part I. polyethylene and polypropylene. \u003cem\u003ePolymer Testing\u003c/em\u003e, \u003cem\u003e116\u003c/em\u003e, 107752. https://doi.org/10.1016/J.POLYMERTESTING.2022.107752\u003c/li\u003e\n\u003cli\u003ePiskuła, P., \u0026amp; Astel, A. M. (2023). Microplastics in Commercial Fishes and By-Catch from Selected FAO Major Fishing Areas of the Southern Baltic Sea. \u003cem\u003eAnimals 2023, Vol. 13, Page 458\u003c/em\u003e, \u003cem\u003e13\u003c/em\u003e(3), 458. https://doi.org/10.3390/ANI13030458\u003c/li\u003e\n\u003cli\u003ePitt, J. A., Aluru, N., \u0026amp; Hahn, M. E. (2024). Microplastics in Marine Food Webs. In S. Shumway \u0026amp; E. Ward (Eds.), \u003cem\u003ePlastics in the Sea: Occurrence and Impacts\u003c/em\u003e. Academic Press.\u003c/li\u003e\n\u003cli\u003ePrata, J. C. (2023). Microplastics and human health: Integrating pharmacokinetics. \u003cem\u003eHttps://Doi.Org/10.1080/10643389.2023.2195798\u003c/em\u003e, \u003cem\u003e53\u003c/em\u003e(16), 1489\u0026ndash;1511. https://doi.org/10.1080/10643389.2023.2195798\u003c/li\u003e\n\u003cli\u003eProvencher, J. F., Ammendolia, J., Rochman, C. M., \u0026amp; Mallory, M. L. (2019). Assessing plastic debris in aquatic food webs: what we know and don\u0026rsquo;t know about uptake and trophic transfer. \u003cem\u003eEnvironmental Reviews\u003c/em\u003e, \u003cem\u003e27\u003c/em\u003e(3), 304\u0026ndash;317. https://doi.org/10.1139/er-2018-0079\u003c/li\u003e\n\u003cli\u003eProvencher, J. F., Bond, A. L., Avery-Gomm, S., Borrelle, S. B., Bravo Rebolledo, E. L., Hammer, S., K\u0026uuml;hn, S., Lavers, J. L., Mallory, M. L., Trevail, A., \u0026amp; Van Franeker, J. A. (2017). Quantifying ingested debris in marine megafauna: a review and recommendations for standardization. \u003cem\u003eAnalytical Methods\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e(9), 1454\u0026ndash;1469. https://doi.org/10.1039/C6AY02419J\u003c/li\u003e\n\u003cli\u003eProvencher, J. F., Covernton, G. A., Moore, R. C., Horn, D. A., Conkle, J. L., \u0026amp; Lusher, A. L. (2020). Proceed with caution: The need to raise the publication bar for microplastics research. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e748\u003c/em\u003e, 141426. https://doi.org/10.1016/J.SCITOTENV.2020.141426\u003c/li\u003e\n\u003cli\u003ePyl, M., Taylor, A., Oberh\u0026auml;nsli, F., Swarzenski, P., Hussamy, L., Besson, M., Danis, B., \u0026amp; Metian, M. (2022). Size-dependent transfer of microplastics across the intestinal wall of the echinoid Paracentrotus lividus. \u003cem\u003eAquatic Toxicology\u003c/em\u003e, \u003cem\u003e250\u003c/em\u003e, 106235. https://doi.org/10.1016/J.AQUATOX.2022.106235\u003c/li\u003e\n\u003cli\u003eQaiser, N., Sidra, S., Javid, A., Iqbal, A., Amjad, M., Azmat, H., Arooj, F., Farooq, K., Nimra, A., \u0026amp; Ali, Z. (2023). Microplastics abundance in abiotic and biotic components along aquatic food chain in two freshwater ecosystems of Pakistan. \u003cem\u003eChemosphere\u003c/em\u003e, \u003cem\u003e313\u003c/em\u003e, 137177. https://doi.org/10.1016/J.CHEMOSPHERE.2022.137177\u003c/li\u003e\n\u003cli\u003eRamsperger, A. F. R. M., Bergamaschi, E., Panizzolo, M., Fenoglio, I., Barbero, F., Peters, R., Undas, A., Purker, S., Giese, B., Lalyer, C. R., Tamargo, A., Moreno-Arribas, M. V., Grossart, H. P., K\u0026uuml;hnel, D., Dietrich, J., Paulsen, F., Afanou, A. K., Zienolddiny-Narui, S., Eriksen Hammer, S., \u0026hellip; Laforsch, C. (2023). Nano- and microplastics: a comprehensive review on their exposure routes, translocation, and fate in humans. \u003cem\u003eNanoImpact\u003c/em\u003e, \u003cem\u003e29\u003c/em\u003e, 100441. https://doi.org/10.1016/J.IMPACT.2022.100441\u003c/li\u003e\n\u003cli\u003eRasta, M., Sattari, M., Taleshi, M. S., \u0026amp; Namin, J. I. (2021). Microplastics in different tissues of some commercially important fish species from Anzali Wetland in the Southwest Caspian Sea, Northern Iran. \u003cem\u003eMarine Pollution Bulletin\u003c/em\u003e, \u003cem\u003e169\u003c/em\u003e, 112479. https://doi.org/10.1016/J.MARPOLBUL.2021.112479\u003c/li\u003e\n\u003cli\u003eRaza, M. H., Jabeen, F., Ikram, S., \u0026amp; Zafar, S. (2023). Characterization and implication of microplastics on riverine population of the River Ravi, Lahore, Pakistan. \u003cem\u003eEnvironmental Science and Pollution Research\u003c/em\u003e, \u003cem\u003e30\u003c/em\u003e(3), 6828\u0026ndash;6848. https://doi.org/10.1007/S11356-022-22440-Y/FIGURES/17\u003c/li\u003e\n\u003cli\u003eRemy, F., Collard, F., Gilbert, B., Comp\u0026egrave;re, P., Eppe, G., \u0026amp; Lepoint, G. (2015). When Microplastic Is Not Plastic: The Ingestion of Artificial Cellulose Fibers by Macrofauna Living in Seagrass Macrophytodetritus. \u003cem\u003eEnvironmental Science and Technology\u003c/em\u003e, \u003cem\u003e49\u003c/em\u003e(18), 11158\u0026ndash;11166. https://doi.org/10.1021/ACS.EST.5B02005\u003c/li\u003e\n\u003cli\u003eRenner, G., Nellessen, A., Schwiers, A., Wenzel, M., Schmidt, T. C., \u0026amp; Schram, J. (2019). Data preprocessing \u0026amp; evaluation used in the microplastics identification process: A critical review \u0026amp; practical guide. \u003cem\u003eTrAC Trends in Analytical Chemistry\u003c/em\u003e, \u003cem\u003e111\u003c/em\u003e, 229\u0026ndash;238. https://doi.org/10.1016/J.TRAC.2018.12.004\u003c/li\u003e\n\u003cli\u003eRicker, WE. (1975). Computation and interpretation of biological statistics of fish populations. \u003cem\u003eFish. Res. Board Can. Bull.\u003c/em\u003e, \u003cem\u003e191\u003c/em\u003e, 1\u0026ndash;382. https://cir.nii.ac.jp/crid/1573950400225789696\u003c/li\u003e\n\u003cli\u003eRochman, C. M., Brookson, C., Bikker, J., Djuric, N., Earn, A., Bucci, K., Athey, S., Huntington, A., McIlwraith, H., Munno, K., Frond, H. De, Kolomijeca, A., Erdle, L., Grbic, J., Bayoumi, M., Borrelle, S. B., Wu, T., Santoro, S., Werbowski, L. M., \u0026hellip; Hung, C. (2019a). Rethinking microplastics as a diverse contaminant suite. \u003cem\u003eEnvironmental Toxicology and Chemistry\u003c/em\u003e, \u003cem\u003e38\u003c/em\u003e(4), 703\u0026ndash;711. https://doi.org/10.1002/ETC.4371\u003c/li\u003e\n\u003cli\u003eRochman, C. M., Brookson, C., Bikker, J., Djuric, N., Earn, A., Bucci, K., Athey, S., Huntington, A., McIlwraith, H., Munno, K., Frond, H. De, Kolomijeca, A., Erdle, L., Grbic, J., Bayoumi, M., Borrelle, S. B., Wu, T., Santoro, S., Werbowski, L. M., \u0026hellip; Hung, C. (2019b). Rethinking microplastics as a diverse contaminant suite. \u003cem\u003eEnvironmental Toxicology and Chemistry\u003c/em\u003e, \u003cem\u003e38\u003c/em\u003e(4), 703\u0026ndash;711. https://doi.org/10.1002/ETC.4371\u003c/li\u003e\n\u003cli\u003eRosas, B. R. C., Sakthi, J. S., Barjau-Gonz\u0026aacute;lez, E., Rodr\u0026iacute;guez-Gonz\u0026aacute;lez, F., Galv\u0026aacute;n-Maga\u0026ntilde;a, F., Ram\u0026iacute;rez, S. F., G\u0026oacute;mez-Ch\u0026aacute;vez, F., Sarkar, S. K., \u0026amp; Jonathan, M. P. (2023). First account of microplastics in pelagic sporting dolphinfish from the eastern Mexican coast of Baja California Sur. \u003cem\u003eEnvironmental Toxicology and Pharmacology\u003c/em\u003e, \u003cem\u003e100\u003c/em\u003e, 104153. https://doi.org/10.1016/J.ETAP.2023.104153\u003c/li\u003e\n\u003cli\u003eSabilillah, A. M., Palupi, F. R., Adji, B. K., \u0026amp; Nugroho, A. P. (2023). Health risk assessment and microplastic pollution in streams through accumulation and interaction by heavy metals. \u003cem\u003eGlobal Journal of Environmental Science and Management\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e(4), 719\u0026ndash;740. https://doi.org/10.22034/GJESM.2023.04.05\u003c/li\u003e\n\u003cli\u003eS\u0026aacute;nchez-Guerrero-Hern\u0026aacute;ndez, M. J., Gonz\u0026aacute;lez-Fern\u0026aacute;ndez, D., Sendra, M., Ramos, F., Yeste, M. P., \u0026amp; Gonz\u0026aacute;lez-Orteg\u0026oacute;n, E. (2023). Contamination from microplastics and other anthropogenic particles in the digestive tracts of the commercial species Engraulis encrasicolus and Sardina pilchardus. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e860\u003c/em\u003e, 160451. https://doi.org/10.1016/J.SCITOTENV.2022.160451\u003c/li\u003e\n\u003cli\u003eSantos, R. G., Machovsky-Capuska, G. E., \u0026amp; Andrades, R. (2021). Plastic ingestion as an evolutionary trap: Toward a holistic understanding. \u003cem\u003eScience\u003c/em\u003e, \u003cem\u003e373\u003c/em\u003e(6550), 56\u0026ndash;60. https://doi.org/10.1126/SCIENCE.ABH0945/SUPPL_FILE/ABH0945_SANTOS_SM.PDF\u003c/li\u003e\n\u003cli\u003eShim, W. J., Kim, S. K., Lee, J., Eo, S., Kim, J. S., \u0026amp; Sun, C. (2022). Toward a long-term monitoring program for seawater plastic pollution in the north Pacific Ocean: Review and global comparison. \u003cem\u003eEnvironmental Pollution\u003c/em\u003e, \u003cem\u003e311\u003c/em\u003e, 119911. https://doi.org/10.1016/J.ENVPOL.2022.119911\u003c/li\u003e\n\u003cli\u003eSu, L., Deng, H., Li, B., Chen, Q., Pettigrove, V., Wu, C., \u0026amp; Shi, H. (2019). The occurrence of microplastic in specific organs in commercially caught fishes from coast and estuary area of east China. \u003cem\u003eJournal of Hazardous Materials\u003c/em\u003e, \u003cem\u003e365\u003c/em\u003e, 716\u0026ndash;724. https://doi.org/10.1016/J.JHAZMAT.2018.11.024\u003c/li\u003e\n\u003cli\u003eSuedel, B. C., Boraczek, J. A., Peddicord, R. K., Clifford, P. A., \u0026amp; Dillon, T. M. (1994). Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems. \u003cem\u003eReviews of Environmental Contamination and Toxicology\u003c/em\u003e, \u003cem\u003e136\u003c/em\u003e, 21\u0026ndash;89. https://doi.org/10.1007/978-1-4612-2656-7_2/COVER\u003c/li\u003e\n\u003cli\u003eSultan, M. B., Rahman, M. M., Khatun, M. A., Shahjalal, M., Akbor, M. A., Siddique, M. A. B., Huque, R., \u0026amp; Malafaia, G. (2023). Microplastics in different fish and shellfish species in the mangrove estuary of Bangladesh and evaluation of human exposure. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e858\u003c/em\u003e, 159754. https://doi.org/10.1016/J.SCITOTENV.2022.159754\u003c/li\u003e\n\u003cli\u003eTabata, Y., Inoue, Y., \u0026amp; Ikada, Y. (1996). Size effect on systemic and mucosal immune responses induced by oral administration of biodegradable microspheres. \u003cem\u003eVaccine\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(17\u0026ndash;18), 1677\u0026ndash;1685. https://doi.org/10.1016/S0264-410X(96)00149-1\u003c/li\u003e\n\u003cli\u003eThompson, J. S. (2015). Size-Selective Foraging of Adult Mummichogs, Fundulus heteroclitus, in Intertidal and Subtidal Habitats. \u003cem\u003eEstuaries and Coasts\u003c/em\u003e, \u003cem\u003e38\u003c/em\u003e(5), 1535\u0026ndash;1544. https://doi.org/10.1007/S12237-014-9913-3/FIGURES/3\u003c/li\u003e\n\u003cli\u003eValente, T., Costantini, M. L., Careddu, G., Berto, D., Piermarini, R., Rampazzo, F., Sbrana, A., Silvestri, C., Ventura, D., \u0026amp; Matiddi, M. (2023). Tracing the route: Using stable isotope analysis to understand microplastic pathways through the pelagic-neritic food web of the Tyrrhenian Sea (Western Mediterranean). \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e885\u003c/em\u003e, 163875. https://doi.org/10.1016/J.SCITOTENV.2023.163875\u003c/li\u003e\n\u003cli\u003eVolkheimer, G. (1974). Passage of particles through the wall of the gastrointestinal tract. \u003cem\u003eEnvironmental Health Perspectives\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e, 215\u0026ndash;225. https://doi.org/10.1289/EHP.749215\u003c/li\u003e\n\u003cli\u003eWidyastuti, S., Susmana Abidin, A., Hikmaturrohmi, H., Tri, B., Ilhami, K., Sofian, N., Kurniawan, H., Jupri, A., Candri, D. A., Frediansyah, A., \u0026amp; Prasedya, E. S. (2023). Microplastic Contamination in Different Marine Species of Bintaro Fish Market, Indonesia. \u003cem\u003eSustainability 2023, Vol. 15, Page 9836\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(12), 9836. https://doi.org/10.3390/SU15129836\u003c/li\u003e\n\u003cli\u003eWu, L., Dai, X., Xu, J., Ou, D., Wang, L., Lin, H., He, W., Lin, H., Du, R., Huang, H., Li, W., \u0026amp; Pan, Z. (2023). Assessment of microplastic contamination in an eastern Pacific tuna (Katsuwonus pelamis) and evaluation of its health risk implication through molecular docking and metabolomics studies. \u003cem\u003eFood Chemistry\u003c/em\u003e, \u003cem\u003e426\u003c/em\u003e, 136507. https://doi.org/10.1016/J.FOODCHEM.2023.136507\u003c/li\u003e\n\u003cli\u003eZhu, W., Liu, W., Chen, Y., Liao, K., Yu, W., \u0026amp; Jin, H. (2023). Microplastics in Antarctic krill (Euphausia superba) from Antarctic region. \u003cem\u003eScience of The Total Environment\u003c/em\u003e, \u003cem\u003e870\u003c/em\u003e, 161880. https://doi.org/10.1016/J.SCITOTENV.2023.161880\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"microplastics-and-nanoplastics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mina","sideBox":"Learn more about [Microplastics and Nanoplastics](http://microplastics.springeropen.com)","snPcode":"43591","submissionUrl":"https://submission.nature.com/new-submission/43591/3","title":"Microplastics and Nanoplastics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"microplastics, fish, translocation, Fourier-transform infrared spectroscopy, Raman spectroscopy, bioaccumulation","lastPublishedDoi":"10.21203/rs.3.rs-4916090/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4916090/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMicroplastics (MPs) have been found in a diverse range of organisms across trophic levels. While a majority of the information on organismal exposure to plastics in the environment comes from gastrointestinal (GI) data, the prevalence of MP particles in other tissues is not well understood. Additionally, many studies have not been able to detect the smallest, most prevalent, MPs (1 µm – 5mm) that are the most likely to distribute to tissues in the body. To address these knowledge gaps, MPs in the GI tract and muscle of Atlantic killifish (\u003cem\u003eFundulus heteroclitus\u003c/em\u003e) collected from two sites on Buzzards Bay, Cape Cod, MA were quantified down to 2 µm in size. Fourier-transform infrared spectroscopy and Raman spectroscopy were used to identify all particles. Of the 2,008 particles analyzed in various fish tissue samples, only 3.4 % (69 particles) were identified as plastic; polymers included nylon, polyethylene, polypropylene, and polyurethane. MP abundance in the GI tract was greater than in the muscle. MPs detected in the GI tract samples also tended to be more diverse in both size and polymer type than those found in the muscle. We found that MPs \u0026lt;50 µm, which are often not analyzed in the literature, were the most common in both the GI tract and muscle samples. There was not a significant correlation between the MP content in the muscle compared to the GI tract, indicating that GI tract MP abundance cannot be used to predict non-GI tract tissue MP content; however, MP abundance in muscle correlated with fish total length, suggesting potential bioaccumulation of these small MPs.\u003c/p\u003e","manuscriptTitle":"The abundance and localization of environmental microplastics in gastrointestinal tract and muscle of Atlantic killifish (Fundulus heteroclitus)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-11 12:16:59","doi":"10.21203/rs.3.rs-4916090/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-09-19T16:30:53+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-17T14:58:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-16T20:14:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"209588590681180295314656052425161455148","date":"2024-08-27T08:14:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"135529180956168060500366282414642250805","date":"2024-08-25T15:30:45+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-08-25T08:02:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-08-15T12:07:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-08-15T12:06:03+00:00","index":"","fulltext":""},{"type":"submitted","content":"Microplastics and Nanoplastics","date":"2024-08-14T22:11:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"microplastics-and-nanoplastics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mina","sideBox":"Learn more about [Microplastics and Nanoplastics](http://microplastics.springeropen.com)","snPcode":"43591","submissionUrl":"https://submission.nature.com/new-submission/43591/3","title":"Microplastics and Nanoplastics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c264c119-e26b-4f81-83b1-4aa2258b6fde","owner":[],"postedDate":"September 11th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-04T16:26:50+00:00","versionOfRecord":{"articleIdentity":"rs-4916090","link":"https://doi.org/10.1186/s43591-024-00101-w","journal":{"identity":"microplastics-and-nanoplastics","isVorOnly":false,"title":"Microplastics and Nanoplastics"},"publishedOn":"2024-11-01 16:20:15","publishedOnDateReadable":"November 1st, 2024"},"versionCreatedAt":"2024-09-11 12:16:59","video":"","vorDoi":"10.1186/s43591-024-00101-w","vorDoiUrl":"https://doi.org/10.1186/s43591-024-00101-w","workflowStages":[]},"version":"v1","identity":"rs-4916090","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4916090","identity":"rs-4916090","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}