Total mercury exposure through canned tuna in oil sold in Quito, Ecuador

Total mercury exposure through canned tuna in oil sold in Quito, Ecuador | 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 Article Total mercury exposure through canned tuna in oil sold in Quito, Ecuador Esteban Trujillo-Cruz, Lenys Fernández, Natalia Carpintero-Salvador, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7160559/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Jan, 2026 Read the published version in npj Science of Food → Version 1 posted 9 You are reading this latest preprint version Abstract Mercury is a toxic chemical present in seafood due to its bioaccumulative nature. Given the frequent consumption of these food products, it is important to know the amount of mercury present in these products so that they can be ingested without triggering adverse health effects for consumers. Therefore, this study quantified total Hg in samples of canned tuna in oil from supermarkets in the Metropolitan District of Quito, Ecuador. Three brands of tuna were analyzed; these were coded as A, B, and C, according to their market price (A < B < C). After analysis using a direct mercury analyzer, total Hg concentrations were 0.22 ± 0.10 mg/kg; 0.63 ± 0.10 mg/ kg; and 0.36 ± 0.15 mg/kg for A, B, and C, respectively. Results indicated that total Hg content of the different brands was within the permissible limits established by surveillance regulations. However, the potential non-cancer risk of methylmercury for consumers of brand C exceeded the limit (> 1) established by the US Environmental Protection Agency. Using the highest total Hg concentration to which the Ecuadorian population is exposed through the consumption of brands A, B and C, for children (body weight 14.5 kg) and adults (body weight 70 kg), the following recommended weekly intake (g of fish/week) was determined for each brand: A: 106 and 512 g; B: 26 and 126 g; C: 64 and 307 g, respectively. Biological sciences/Ecology Earth and environmental sciences/Ecology Earth and environmental sciences/Environmental sciences Figures Figure 1 Figure 2 Introduction Tuna is an important source of protein worldwide 1 and Ecuador is one of its major producers and exporters in Latin America 2 – 5 . Accordingly, the tuna industry must follow norms for food quality and safety. According to the Ecuadorian National Fisheries Institute, the main species of tuna found in Ecuador are yellowfin tuna ( Thunnus albacares ), bigeye tuna ( Thunnus obesus ), and skipjack tuna ( Katsuwonus pelamis ) 3 , 4 . Much of Ecuadorian tuna is canned in different oils (sunflower, olive, and vegetable) and water 6 . Ecuador is on the red list of mercury (Hg)-emitting countries, releasing approximately 50 tons of this metal into the environment 7 . Natural and anthropogenic activities, particularly those from artisanal mining, as well as bioaccumulation have caused these levels to increase 8 . Tuna is among the marine fish species able to bioaccumulate a substantial amount of Hg, in part because they filter an enormous amount of phytoplankton and are located at a higher level of the food chain. This is concerning, as it suggests that if Ecuadorian tuna is harvested from Hg-contaminated waters, consumers are being offered products of poor quality, which results in low food security. Mercury is ubiquitous in the environment, and its bioaccumulation in fish depends on their size, diet, and trophic group 9 . Additionally, storage conditions for canned tuna, such as pH, oxygen concentration inside the can, and coating quality, can also increase Hg concentration 10 . Furthermore, the level of Hg toxicity in organisms may vary depending on Hg type and route of exposure. This metal is present in elemental, inorganic, and organic forms 11 . In marine environments, inorganic Hg passes through organisms’ biological membranes and is transformed into methylmercury (Me-Hg), the most toxic form for the biota. The mercury methylation process begins with anaerobic bacteria; Me-Hg is subsequently assimilated by organisms from higher trophic levels through their diets, which causes biomagnification through food webs 12 . Sulfate-reducing bacteria are key methylating agents. The biomagnification of Me-Hg along the food chain results in elevated Hg concentrations in top predators 13 , 14 . As species with a relatively long lifespan, tuna could also have high Me-Hg content. Approximately 80–90% of the Hg present in fish is Me-Hg, while the remaining 10% is inorganic Hg 15 . Absorption of Me-Hg via the gastrointestinal tract may be around nine times greater than that of its inorganic counterparts, which are absorbed in approximately 10% of the gastrointestinal tract. Therefore, consuming fish with high concentrations of Hg poses a considerable health risk 16 , 17 . The biological half-life of Me-Hg is approximately 65 days. Chronic Hg poisoning in an adult weighing 70 kg may result from the daily intake of approximately 0.3 mg of Me-Hg, which represents Hg concentrations of 0.2 mg/L in blood and 60 mg/kg in hair 18 . At the cellular level, the presence of Me-Hg can increase intracellular Ca 2+ , inhibit protein synthesis, disrupt microtubules, and lead to overproduction of free radicals because of the formation of reactive oxygen species in the kidney, liver, and brain 19 , 18 , 20 , 21 . These chronic impacts on a living organism have long-lasting effects that can affect entire generations. Various techniques have been used to quantify Hg in fish, including atomic absorption spectroscopy 22 , 23 neutron activation analysis 24 , gas chromatography 25 , 26 , inductively coupled plasma-mass spectrometry 23 , 27 , high-performance liquid chromatography 27 , atomic fluorescence spectrometry 23 , 28 , 29 , and differential pulse anodic stripping voltammetry 30 , 31 . In 2006, the European Commission regulation established a maximum permissible concentration of Hg in food products of 0.5–1.0 mg/kg (fresh weight), which depends on the species, and a limit for food supplements that cannot exceed 0.1 mg/kg 32 . Assessing Hg content in canned tuna has received little attention in Latin American countries, as it is widely assumed that its concentrations are low 33 . In Ecuador, few studies have examined Hg content in canned tuna 22 . One study in 2015 quantified Hg in canned commercial tuna from the city of Manta in the Ecuadorian province of Manabí 34 ; cold vapor atomic absorption spectroscopy showed Hg did not exceed Ecuador’s permissible limits and Aguilra-Miranda et al. 29 , reported using atomic fluorescence spectroscopy that the Hg content of canned tuna in water also did not exceed standards, however, the amounts of Hg in those samples were found to be risky to health. Extending these researches, the current study quantified total Hg (THg) in samples of canned tuna in oil from the most popular brands on the Ecuadorian market. The results were compared to current national and international regulations and guidelines on permissible Hg limits in food matrixes, as well as with data from the literature, to evaluate its safety for consumption. Experimental Sampling From March 2023 to March 2024, sixty cans of 80-gr of tuna were collected from local supermarkets on the south and north sides of Quito - Ecuador. Brands were coded as A, B, and C according to the price at which they are sold in the market (A < B < C). Twenty cans of solid tuna in oil were collected for each brand; each can belonged to different batches. The canned tuna samples must follow national (e.g., the Ecuadorian Standards Institute, Ministry of Agriculture and Livestock, National Fisheries Institute) and international (e.g., WTO, CIAT, FDA, WHO, FAO, ISO, IFS, BRC, dolphin-safe, halal, kosher) quality and safety standards and labels and must have a valid sanitary registration. Sample treatment The oil inside the can was drained, and the tuna meat was homogenized using a blender with a stainless-steel blade. From each can, 60 g was taken and weighed in petri dishes, placed in an ultra-freezer for 1 h, and lyophilized for 48 h until a constant weight was achieved. The percentage moisture content of each can was calculated. Quantification of total mercury Total mercury (THg) was quantified using a Milestone DMA-80 Direct Mercury Analyzer from Core Lab de Ciencias Ambientales - USFQ, following the EPA 7473 method 35 . Approximately 40 mg ± 5 mg of dried sample were placed into a nickel sample boat and introduced into a catalytic furnace. The sample underwent a two-step process, first, it was dried and thermally decomposed in an aerobic atmosphere; second, the resulting gases passed through a catalytic section where halogens, nitrogen oxides, and sulfur oxides were selectively trapped and removed by a continuous gas flow. The liberated Hg vapor was then transported by compressed air to a gold amalgamator, where it was selectively captured. The amalgamator was subsequently heated to release the bound Hg, which passed through two atomic absorption cells with different sensitivity ranges (cell 1: 0.5–20 ng Hg; cell 2: 20–1000 ng Hg) for quantification. Mercury detection was performed via atomic absorption spectrophotometry using a 254 nm Hg vapor lamp. All analyses were performed in triplicate to ensure data reliability. Additionally, three blank samples, consisting of empty sample boats, were analyzed at the beginning of each run and after every 15 replicates, in order to verify the absence of contamination in the system that could interfere with mercury detection. To monitor analytical accuracy, the DORM-4 certified reference material (CRM) (fish protein) was used as a quality control standard at the start of the analysis and after every 10 samples. These results were considered reliable, as the precision and accuracy values were within the limits permitted by the AOAC ("AOAC SMPR 2012.007: Standard Method Performance Requirements for Determination of Heavy Metals in a Variety of Foods and Beverages," 2013). Risk assessment Consumer health risk was assessed for different THg concentrations (minimum, mean, and maximum). All calculations were performed using Microsoft Office Professional Plus Excel 2016. The level of exposure (Ex) to Me-Hg was calculated using the following equation from the US Environmental Protection Agency (EPA): \(\:Ex=\frac{\text{C}\text{x}\:\times\:\text{C}\text{R}}{\text{B}\text{W}}\) , where Cx is the concentration of metal in the edible portion of the samples (mg/kg), CR is the mean amount of tuna (kg) consumed daily, and BW is the consumer's body weight (kg) 67 (US-EPA, 2000). The potential non-cancer risk (Rx) from consumption was determined using the following equation: \(\:Rx=\frac{Ex}{\text{R}\text{f}\text{D}}\) 36 , where Ex is the exposure to the pollutant (mg / (kg‧d)), and RfD is the reference dose of the chemical (mg / (kg‧d) 36 . Considering the Provisional Tolerable Weekly Intake (PTWI) for methylmercury (MeHg) of 1.6 µg/kg of human body weight (HBW), as established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) 37 , the maximum weekly intake of canned tuna (in grams per week) was estimated using the following equation: Intake(g) = PTWI×HBW/Cx. Where Cx is the average concentration of MeHg (mg/kg) determined for each canned tuna brand in this study. For the purposes of this calculation, the HBW was set at 70 kg for adults and 14.5 kg for children. Data analysis To calculate descriptive statistics (mean, standard deviation, range, and recovery), Excel 2016 was used. Boxplots and Chebyshev's theorem 38 were used to evaluate data distribution; the latter was implemented using R software. THg content between the three different canned tuna brands was assessed using non-parametric methods (Kruskall Wallis) followed by a pairwise Wilcox test. Results and Discussion Quantification of total mercury content Food safety authorities have established various regulations and guidelines to control Hg levels in canned tuna meat to protect public health. These regulations vary by country and organization but generally aim to limit mercury exposure from tuna consumption. The EU, in Regulation (EC) No. 629/2008, set the maximum level of Hg allowed in predatory species at 1.0 mg/kg w/w and 0.5 mg/kg w/w for other fish species, while the US Food and Drug Administration (FDA) set the level for tuna at 1.0 mg/kg; however, the US EPA set 0.5 mg/kg w/w as the level safe for human consumption. On the other hand, the Canadian Food Inspection Agency (CFIA) established 0.5 mg/kg w/w as the maximum for canned tuna and 1.0 mg/kg w/w for fresh/frozen tuna 39 . Considering the maximum tuna Hg levels set by the EU, US, and CFIA, Table 1 , shows that none of the tuna brands exceeded the established thresholds. However, the Hg limits for canned albacore, specifically canned white and light tuna ( skipjack tuna ), established by the FDA in 2008 (FDA Website 2008) are 0.035 mg/kg and 0.0112 mg/kg, respectively. Considering these limits, all brands far exceeded these concentrations. Nevertheless, according to the Ecuadorian National Fisheries Institute, these species are not used in Ecuadorian canned tuna products, but it remains a cause for concern. Table 1 Total mercury levels ± standard deviation (mg·kg - 1 w.w.) in the three brands of canned tuna analyzed per every year of the studied period. Total mercury levels (mgkg − 1 ) Brand A Brand B Brand C 0.22 ± 0.10 (0.05–0.40) 0.63 ± 0.10 (0.48–0.89) 0.36 ± 0.15 (0.14–0.61) According to the boxplot analysis (Fig. 1 ), the data distribution for Brand B was negatively skewed, as the mean was greater than the median and the mode; while for Brand C, the distribution was positively skewed. For brand A, the distribution was symmetric because the mean and median are very close (Gaussian behavior). For brand B, 75% of the data indicated that the THg content was between 0.482 and 0.665 mg/kg; for brand A, the content was between 0.045 and 0.225 mg/kg and for brand C, between 0.14 and 0.50 mg/kg. Brand B, which corresponds to the intermediate price in the Ecuadorian market, had an average THg value of 0.6294 mg/kg and was therefore the closest to exceeding the Ecuadorian limit of 0.5 mg/kg; Brand A, which sold at the lowest price on the market, had the lowest THg content. For the brand with the highest market price, an intermediate THg content level was found compared to the other two brands. Kruskal-Wallis test revealed statistically significant differences in total mercury (THg) concentrations among the three canned tuna brands analyzed (p < 0.01). Subsequent pairwise comparisons using the Wilcoxon test indicated that brand B's THg levels were significantly different from those of brands A and C. This distinction appears to be influenced by two specific batches from brand B that exhibited the highest THg concentrations. The p-values for brands A, B, and C were 0.1228, 0.3788, and 0.4035, respectively, according to the Kruskal-Wallis test. Chebyshev’s theorem was applied to estimate the confidence intervals and assess the degree of dispersion within each dataset. This theorem allows for calculating the minimum proportion of population values that lie within k standard deviations from the mean using the expression \(\:(1-\frac{1}{{k}^{2}})\) , ​ and conversely, the maximum proportion of values falling outside this range using ( \(\:\frac{1}{{k}^{2}}\) ), where k represents the number of standard deviations and must be greater than 1. In Table 2 , the confidence intervals were computed using specific k values: π, φ, and e , which were chosen for their relevance in modelling natural and artificial systems 40 . When k was set to π (3.1416), Chebyshev’s theorem predicted that at least 89.87% of the data fell within that range from the mean. For e (2.72), the corresponding coverage was 86.47%, and for φ (1.618), it dropped to 61.80%. Moreover, the results shown in Table 2 indicate that brand C exhibits the widest confidence interval among the analyzed brands. According to Chebyshev’s theorem, if new observations are added to the population of brand C, there is an 89.87% likelihood (with k = π) that these new data points will fall within π standard deviations of the mean. This supports the conclusion that brand C consistently presents intermediate THg levels compared to brands A and B, with a higher degree of statistical confidence. Table 3 compares this study’s results to those in the literature published. The THg values fall within the ranges reported by most of the previous studies, with the exception of those for samples from Mexico 41 , suggesting a potential violation of the permissible Hg limit for canned products in this region. Table 2 Confidence intervals, according to uncertainties about the distribution of the data, obtained from Chebyshev 's theorem Standard Deviations Minimum % within [1-(1/k 2 )] Max % outside [1/k 2 ] Brand A confidence interval Brand B confidence interval Brand C confidence interval π (3.141593) 0.8987 0.1013 (-0.16769, 0.2870796) (-0.227532,0.674699) (-0.05291418,0.4118852) e (2.71828) 0.8647 0.1353 (-0.152221,0.302559) (0.2427424,0.6899189) (-0.03710402,0.4277052) φ (1.618034) 0.6180 0.3197 (-0.040059,0.386385) (0.3530297, 0.7723444) (0.07753211,0.5133809) Table 3 Studies on THg content in canned tuna in water and oil performed in other countries. Type of preserved canned City / Country of study Origin of samples Species Technique Mean Total Hg (mg·kg − 1 ) References Conserved in water New Jersey, Unites States United States Thunnus germo and Katsuwonus pelamis Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) 0.096 to 0.431 42 Lower Austria, Burgenland and from Viennese retail operations Different brand Tuna not specified 0.14 43 Not specified Las Vegas, Unites States Not specified Tuna not specified Atomic Absorption Mercury Analyser (AMA) 0.541 to 0.714 44 Not specified Tyrrhenian Sea Not specified Tuna not specified Atomic absorption spectroscopy (AAS) 0.04 to 1.79 45 Conserved in water and oil Mazatlán, Mexico Mexico Thunnus albacares Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) 0.25 to 0.51 10 Olive oil, sunflower seed oil, water or marinade Spain The most popular brands in Spain Yellowfin, bigeye tuna, and skipjack tuna Atomic absorption spectrometry and thermal decomposition amalgamation 46 Not specified Italy, Libya, Spain and Thailand Different brand origin and country of manufacture Tuna skipjack and yellowfin Direct Mercury Analyzer (DMA) 0.163 47 Spain Spain Thunnus albacares and Thunnus alalunga Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) 0.332 ± 0.151 39 Conserved in oil Sao Paulo, Brazil Not specified Tuna not specified Thermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS) 0.044 to 0.402 48 Conserved in water Sao Paulo, Brazil Not specified Tuna not specified Thermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS) 0.051 to 0.460 48 Conserved in water Vojvodina, Serbia Thailand, Vietnam, Indonesia and Spain Tuna not specified Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) 0.007 to 0.640 49 Conserved in water Portugal Caught by commercial vessels from the Eastern Central Atlantic Ocean Skipjack tuna Thermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS 0.134 50 Conserved in water Cartagena, Colombia Ecuador and Colombia Tuna not specified Direct Mercury Analyzer (DMA) < 0.001 to 0.86 51 Conserved in oil Cartagena, Colombia Supermarkets located in Cartagena (10°25′25″N 75°31′31″W) on Colombia’s northern coast Tuna not specified Direct Mercury Analyzer (DMA) ∼0.610 51 Not specified Iran Purchased from 10 different markets in Tehran Thunnus albacares, (Clupeonella cultriventris caspia, Euthynnus affinis, Thunnus tonggol Inductively coupled plasma optical emission spectrometry (ICP-OES ) 0.13 52 Conserved in water Ecuador Not specified Tuna not specified Cold vapour atomic absorption spectrophotometry (CV-AAS) 0.022 to 0.093 53 Conserved in oil Serbian Not specified Tuna not specified Coupled Plasma-Mass Spectrometry (ICP-MS) 0.03 to 0.068 54 Shredded in vegetable oil Barranquilla, Colombia China, Ecuador, and Colombia Thunnus albacares Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) 0.1311 to 1.4725 33 Conserved in oil Iran Persian Gulf Tuna not specified Atomic Absorption Spectrometer (FAAS) 177–315,3 ppb 55 Not specified Tijuana, Mexico Not specified Thunnus albacares Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) 0.005 to 1.17 56 Not specified Italy Different brands sold in different markets Tuna not specified Standard methods: EN 13805:2014 0.207 57 Conserved in oil Italy Italian market Tuna not specified Atomic absorption spectroscopy (AAS) 0.041 Conserved in water and oil Ecuador Eastern Pacific international waters Katsuwonus pelamis, Thunnus albacares, and Thunnus tuna Cold vapor atomic absorption Spectroscopy (CV-AAS) ∼ 0.043 6 Not specified Foggia, Italy Not specified Tuna not specified Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) 0.207 ± 0.18 57 Conserved in water Quito, Ecuador Ecuador Tuna not specified Cold Vapor Atomic Fluorescence Spectrophotometry (CV-AFS) 0.02 to 1.98 29 Conserved in water Quito, Ecuador Ecuador Tuna not specified Direct Mercury Analyzer (DMA 0.22 to 0.23 This study Regarding the medium in which the tuna is preserved inside the cans, the results indicate no a priori difference in THg content between samples of the same brands preserved in water, according to the report by Aguilar-Miranda et al. 29 , and those preserved in oil, according to the present study. The possible differences between these results and those from the studies presented in Table 3 may be due to differences in species, size, fish lifespan, and capture site. For example, according to Farrell Anthony 58 , skipjack tuna ( Katsuwonus pelamis ), which is highly popular in terms of fishing and represents 58% of global tuna catch 66 , has a shorter lifespan and therefore accumulates less Hg in its tissues. Thunnus alalunga reaches a maximum weight of approximately 40 kg at 15 years old, while Katsuwonus pelamis has a maximum weight of approximately 30 kg at the same age. Considering the widespread consumption of canned tuna globally and the potential Hg-related side effects for human health, the species, size, and catch location should be required and regulated on labels. In this regard,Shim et al. 59 suggested that, because of young children’s susceptibility to Hg’s toxic effects, products with low metal concentrations should be specially labeled as “safe for children”; they proposed that the maximum Hg content for commercial fish be reduced to 0.185 mg/kg. Generally, this information is confusing or insufficient on such labels and limits a more consistent assessment when comparing results between different regions. Since December 13, 2014, the EU has implemented changes in the regulations for labeling all fishery and aquaculture products. For products such as canned fish, information on the capture zone shown in the barcodes is voluntary, unlike for unprocessed fish products, for which the capture zone must be specified; however, many retailers have chosen to provide this information 60 . In Ecuador, the labels on this type of product only provide nutritional information. Given the widespread consumption of canned tuna and the potential health risks, it is recommended that product labels include information on species, size, and catch location. In this context, Shim et al. 59 proposed that products with low Hg levels should be specially labeled as “safe for children.” However, in Ecuador, labeling for these products currently only includes nutritional information. Human health risk assessment In marine environments, inorganic Hg passes through biological membranes and transforms into Me-Hg, which could be an indication of a biomagnification process of Hg in the food web, given that Me-Hg is highly lipophilic. The study methodology used allowed THg values to be measured only in the samples. However, the literature has suggested that, depending on the species, particularly for fish such as tuna, when analyzing muscle tissue, Me-Hg constitutes a significant percentage of THg content, ranging from 80 to 100% in some cases 61 . Table 4 shows the results obtained of the exposure levels, potential non-carcinogenic risk, and recommended weekly intake of fish meat, for children and adults, based on mean content of THg found in the three brands of canned tuna in oil. The level of exposure to THg (Ex) calculated, in none of the brands exceed the FDA reference dose of 0.1 mg/kg day BW -1 62, 63 . However, for an adult weighing 70 kg and a child weighing 14.5 kg, the non-carcinogenic potential risk (Rx) values were greater than or close to 1 for Brand C, 1.4 and 0.6, respectively, suggesting that consuming tuna from this brand poses a health risk. Based on these results, the recommended weekly intake of fish meat for children and adults was calculated. According to the FDA/EPA, 2022, 64 the highest allowable THg concentration in fish when eating 1 serving per week is 0.46 mg kg − 1 . The suggested weekly consumption values, calculated from the highest THg concentration found for each brand for children (body weight 14.5 kg) and adults (body weight 70 kg), were 106 and 512 g fish/week for brand A; 26 and 126 g fish/week for brand B; and 64 and 307 g fish/week for brand C, respectively. These results suggest that consuming canned tuna in oil in higher quantities could have negative consequences for human health. Brand A allows for the highest weekly consumption. Consuming more than six 80g can of tuna with a higher Hg content per week may pose a risk to Ecuadorian consumers. According to Ormaza et al. 6 , canned tuna in Ecuador is consumed once or twice a week, although not consistently. Assuming a weekly portion of 80 g for adults and 40 g for children (half a can), the non-carcinogenic risk index (Rx) calculated for the average THg concentration in brand C exceeds 1. This suggests a significant potential risk when consuming more than one portion per week, particularly for vulnerable populations such as pregnant women and children. For brands A and B, the risk is lower, though children remain more vulnerable than adults do. In other countries, such as Mexico, studies have reported low non-carcinogenic risks associated with canned tuna consumption; however, consumption levels vary greatly. For example, average daily tuna intake is 3.92 g in Mexico and 5.71 g in Italy, while in Ecuador; the estimated daily fish consumption is 37.0 g, though it's not specified whether this includes canned tuna. Therefore, frequent consumption of tuna or other fish species should be a health concern. The estimated risk of THg exposure, using the hazard quotient (HQ) value and mean concentration of Me-Hg (0.80xTHg) in the samples 51 , was much higher than 1 for all brands (Table 4 ), indicating possible adverse health effects for consumers. Similarly, using the calculated mean Me-Hg concentration in each sample, the Table 4 shows the recommended maximum allowable rate of consumption of tuna in meals/week, CRmw 65 . This is also graphically presented in Fig. 2 as HQ vs. CRmw; the results confirm that indeed the brand A could be consumed in a greater number of meals per week. Table 4 Exposure levels, potential non-carcinogenic risk, and recommended weekly intake of fish meat for children and adults, based on mean content of MeHg found in the three brands of canned tuna in water. Brand A Brand B Brand C Ex (mg kg − 1 day BW − 1 ) Rx Recommended weekly intake (g fish/week) HQ CRmw Ex (mg·kg − 1 day BW − 1 ) Rx Recommended weekly intake (g fish/week) HQ CRmw Ex (mg·kg − 1 day BW − 1 ) Rx Recommended weekly intake (g fish/week) HQ CRmw Children a 8.62 x 10 − 5 0.9 106 9.65 19.32 2.48 x 10 − 4 2.5 26 27.78 6.71 1.44 x 10 − 4 1.44 64 16.10 11.57 Adult b 3.57 x 10 − 5 0.4 512 1.99 4.00 1.03 x 10 − 4 1.0 126 5.75 1.39 5.90 x 10 − 5 0.60 307 3.34 2.40 *PTWI (µg MeHg·kg − 1 HBW): 1.6 a Body weight of 14.5 kg for children; b Body weight of 70 kg for adults *Hazard quotient (HQ) Conclusions Among the three canned tuna, brands analyzed, also among the most consumed in Ecuador, brand B exhibited the highest THg concentration, reaching up to 0.63mg kg⁻¹. Despite this, the majority of samples from brands A, B, and C presented THg levels below the maximum limits established by national and international food safety standards. The observed variability in THg concentrations among brands can likely be explained by factors such as the species, size, age, fat content of the fish, and environmental conditions of the capture area. Mercury accumulation in tuna is known to depend on ecological parameters including the degree of aquatic pollution, geographic origin, and seasonal variation at the time of capture. Risk assessment based on the estimated MeHg intake (Rx) indicated that consuming a single weekly serving of 80 g for adults and 40 g for children does not represent a significant non-carcinogenic health risk. However, increasing portion size or consumption frequency may pose a greater risk for vulnerable groups, especially children, due to their lower body weight and developing systems. While fish intake is nutritionally beneficial, its consumption must be balanced to minimize potential mercury exposure. Given the potential health implications, particularly for pregnant women and children, it is strongly recommended to implement national strategies for routine monitoring of mercury levels in canned tuna and other commonly consumed fish products. Additionally, Ecuador’s regulatory framework should mandate the labeling of tuna species and catch origin on packaging, as these factors are critical for assessing risk. Improved labeling would empower consumers to make informed choices and avoid species known for higher mercury accumulation. This study provides relevant evidence on THg levels in the most widely consumed canned tuna brands in the Ecuadorian market, highlighting the need to strengthen food safety monitoring and surveillance systems. Although risk assessment for MeHg exposure suggests that occasional consumption within recommended portion sizes does not pose a significant threat to the adult population, cumulative exposure in vulnerable groups such as children and pregnant women may present a public health concern. Therefore, it is imperative to promote policies that support sustainable fishing practices, improved labeling standards, and public education campaigns aimed at encouraging safe and informed fish consumption across the country. Declarations Conflicts of interest There are no conflicts of interest to declare. Author Contribution ETC: data curation and methodology; LF: contributed to funding acquisition, conceptualisation, data curation, formal analysis, methodology, project administration, supervision and writing; NCS: contributed to data acquisition, data curation, methodology and supervision; MRU: contributed to data acquisition, data curation and methodology; EOMM: contributed to formal analysis; DBM: contributed to data curation and methodology; PEM: contributed to data curation and writing. Acknowledgements The authors of this research thank the Research Directorate of the Pontificia Universidad Católica del Ecuador for their funding. Data availability Data “available on request”: [email protected] References Zuleta, L., Becerra, A., 2013. El mercado del atún en Colombia [WWW Document]. Fedesarrollo. URL https://repository.fedesarrollo.org.co/bitstream/handle/11445/205/El%20mercado%20del%20atun%20en%20Colombia%20.pdf?sequence=2&isAllowed=y (accessed 11.21.23). Anastacio, J., 2019. 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1","display":"","copyAsset":false,"role":"figure","size":34682,"visible":true,"origin":"","legend":"\u003cp\u003eBox plot of the total mercury content (mg Kg\u003csup\u003e-1\u003c/sup\u003e), for the three analyzed Brands of canned tuna in oil.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7160559/v1/e3a0df987d11706f9add0050.jpg"},{"id":88118728,"identity":"b79d76e1-60e2-4177-b783-bfd851370cf1","added_by":"auto","created_at":"2025-08-01 15:16:31","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":74032,"visible":true,"origin":"","legend":"\u003cp\u003eHQ \u003cem\u003evs.\u003c/em\u003eCRmw for each brand analyzed\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7160559/v1/9affc3228dc5c7b1bbb05523.jpg"},{"id":100614573,"identity":"f02cde08-23da-406a-819a-6b78f53bd49f","added_by":"auto","created_at":"2026-01-19 17:22:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1094459,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7160559/v1/e288113c-99a0-4a63-a026-03d80d211c6f.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Total mercury exposure through canned tuna in oil sold in Quito, Ecuador","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTuna is an important source of protein worldwide \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e and Ecuador is one of its major producers and exporters in Latin America \u003csup\u003e\u003cspan additionalcitationids=\"CR3 CR4\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Accordingly, the tuna industry must follow norms for food quality and safety.\u003c/p\u003e\u003cp\u003eAccording to the Ecuadorian National Fisheries Institute, the main species of tuna found in Ecuador are yellowfin tuna (\u003cem\u003eThunnus albacares\u003c/em\u003e), bigeye tuna (\u003cem\u003eThunnus obesus\u003c/em\u003e), and skipjack tuna (\u003cem\u003eKatsuwonus pelamis\u003c/em\u003e) \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Much of Ecuadorian tuna is canned in different oils (sunflower, olive, and vegetable) and water\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eEcuador is on the red list of mercury (Hg)-emitting countries, releasing approximately 50 tons of this metal into the environment \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Natural and anthropogenic activities, particularly those from artisanal mining, as well as bioaccumulation have caused these levels to increase \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Tuna is among the marine fish species able to bioaccumulate a substantial amount of Hg, in part because they filter an enormous amount of phytoplankton and are located at a higher level of the food chain. This is concerning, as it suggests that if Ecuadorian tuna is harvested from Hg-contaminated waters, consumers are being offered products of poor quality, which results in low food security.\u003c/p\u003e\u003cp\u003eMercury is ubiquitous in the environment, and its bioaccumulation in fish depends on their size, diet, and trophic group \u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Additionally, storage conditions for canned tuna, such as pH, oxygen concentration inside the can, and coating quality, can also increase Hg concentration\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Furthermore, the level of Hg toxicity in organisms may vary depending on Hg type and route of exposure. This metal is present in elemental, inorganic, and organic forms \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. In marine environments, inorganic Hg passes through organisms\u0026rsquo; biological membranes and is transformed into methylmercury (Me-Hg), the most toxic form for the biota. The mercury methylation process begins with anaerobic bacteria; Me-Hg is subsequently assimilated by organisms from higher trophic levels through their diets, which causes biomagnification through food webs \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Sulfate-reducing bacteria are key methylating agents.\u003c/p\u003e\u003cp\u003eThe biomagnification of Me-Hg along the food chain results in elevated Hg concentrations in top predators \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. As species with a relatively long lifespan, tuna could also have high Me-Hg content. Approximately 80\u0026ndash;90% of the Hg present in fish is Me-Hg, while the remaining 10% is inorganic Hg \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Absorption of Me-Hg via the gastrointestinal tract may be around nine times greater than that of its inorganic counterparts, which are absorbed in approximately 10% of the gastrointestinal tract. Therefore, consuming fish with high concentrations of Hg poses a considerable health risk\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe biological half-life of Me-Hg is approximately 65 days. Chronic Hg poisoning in an adult weighing 70 kg may result from the daily intake of approximately 0.3 mg of Me-Hg, which represents Hg concentrations of 0.2 mg/L in blood and 60 mg/kg in hair\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. At the cellular level, the presence of Me-Hg can increase intracellular Ca\u003csup\u003e2+\u003c/sup\u003e, inhibit protein synthesis, disrupt microtubules, and lead to overproduction of free radicals because of the formation of reactive oxygen species in the kidney, liver, and brain \u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. These chronic impacts on a living organism have long-lasting effects that can affect entire generations.\u003c/p\u003e\u003cp\u003eVarious techniques have been used to quantify Hg in fish, including atomic absorption spectroscopy \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e neutron activation analysis\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e, gas chromatography\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e, inductively coupled plasma-mass spectrometry\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e, high-performance liquid chromatography\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e, atomic fluorescence spectrometry \u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e, and differential pulse anodic stripping voltammetry\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIn 2006, the European Commission regulation established a maximum permissible concentration of Hg in food products of 0.5\u0026ndash;1.0 mg/kg (fresh weight), which depends on the species, and a limit for food supplements that cannot exceed 0.1 mg/kg\u003csup\u003e32\u003c/sup\u003e. Assessing Hg content in canned tuna has received little attention in Latin American countries, as it is widely assumed that its concentrations are low\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. In Ecuador, few studies have examined Hg content in canned tuna \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. One study in 2015 quantified Hg in canned commercial tuna from the city of Manta in the Ecuadorian province of Manab\u0026iacute; \u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e; cold vapor atomic absorption spectroscopy showed Hg did not exceed Ecuador\u0026rsquo;s permissible limits and Aguilra-Miranda et al.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e, reported using atomic fluorescence spectroscopy that the Hg content of canned tuna in water also did not exceed standards, however, the amounts of Hg in those samples were found to be risky to health. Extending these researches, the current study quantified total Hg (THg) in samples of canned tuna in oil from the most popular brands on the Ecuadorian market. The results were compared to current national and international regulations and guidelines on permissible Hg limits in food matrixes, as well as with data from the literature, to evaluate its safety for consumption.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cp\u003e\u003cb\u003eSampling\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFrom March 2023 to March 2024, sixty cans of 80-gr of tuna were collected from local supermarkets on the south and north sides of Quito - Ecuador. Brands were coded as A, B, and C according to the price at which they are sold in the market (A\u0026thinsp;\u0026lt;\u0026thinsp;B\u0026thinsp;\u0026lt;\u0026thinsp;C). Twenty cans of solid tuna in oil were collected for each brand; each can belonged to different batches. The canned tuna samples must follow national (e.g., the Ecuadorian Standards Institute, Ministry of Agriculture and Livestock, National Fisheries Institute) and international (e.g., WTO, CIAT, FDA, WHO, FAO, ISO, IFS, BRC, dolphin-safe, halal, kosher) quality and safety standards and labels and must have a valid sanitary registration.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSample treatment\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe oil inside the can was drained, and the tuna meat was homogenized using a blender with a stainless-steel blade. From each can, 60 g was taken and weighed in petri dishes, placed in an ultra-freezer for 1 h, and lyophilized for 48 h until a constant weight was achieved. The percentage moisture content of each can was calculated.\u003c/p\u003e\u003cp\u003e\u003cb\u003eQuantification of total mercury\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTotal mercury (THg) was quantified using a Milestone DMA-80 Direct Mercury Analyzer from Core Lab de Ciencias Ambientales - USFQ, following the EPA 7473 method\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. Approximately 40 mg\u0026thinsp;\u0026plusmn;\u0026thinsp;5 mg of dried sample were placed into a nickel sample boat and introduced into a catalytic furnace. The sample underwent a two-step process, first, it was dried and thermally decomposed in an aerobic atmosphere; second, the resulting gases passed through a catalytic section where halogens, nitrogen oxides, and sulfur oxides were selectively trapped and removed by a continuous gas flow. The liberated Hg vapor was then transported by compressed air to a gold amalgamator, where it was selectively captured. The amalgamator was subsequently heated to release the bound Hg, which passed through two atomic absorption cells with different sensitivity ranges (cell 1: 0.5\u0026ndash;20 ng Hg; cell 2: 20\u0026ndash;1000 ng Hg) for quantification. Mercury detection was performed via atomic absorption spectrophotometry using a 254 nm Hg vapor lamp.\u003c/p\u003e\u003cp\u003eAll analyses were performed in triplicate to ensure data reliability. Additionally, three blank samples, consisting of empty sample boats, were analyzed at the beginning of each run and after every 15 replicates, in order to verify the absence of contamination in the system that could interfere with mercury detection. To monitor analytical accuracy, the DORM-4 certified reference material (CRM) (fish protein) was used as a quality control standard at the start of the analysis and after every 10 samples. These results were considered reliable, as the precision and accuracy values were within the limits permitted by the AOAC (\"AOAC SMPR 2012.007: Standard Method Performance Requirements for Determination of Heavy Metals in a Variety of Foods and Beverages,\" 2013).\u003c/p\u003e\u003cp\u003e\u003cb\u003eRisk assessment\u003c/b\u003e\u003c/p\u003e\u003cp\u003eConsumer health risk was assessed for different THg concentrations (minimum, mean, and maximum). All calculations were performed using Microsoft Office Professional Plus Excel 2016.\u003c/p\u003e\u003cp\u003eThe level of exposure (Ex) to Me-Hg was calculated using the following equation from the US Environmental Protection Agency (EPA): \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Ex=\\frac{\\text{C}\\text{x}\\:\\times\\:\\text{C}\\text{R}}{\\text{B}\\text{W}}\\)\u003c/span\u003e\u003c/span\u003e, where Cx is the concentration of metal in the edible portion of the samples (mg/kg), CR is the mean amount of tuna (kg) consumed daily, and BW is the consumer's body weight (kg)\u003csup\u003e\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e67\u003c/span\u003e\u003c/sup\u003e (US-EPA, 2000). The potential non-cancer risk (Rx) from consumption was determined using the following equation: \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Rx=\\frac{Ex}{\\text{R}\\text{f}\\text{D}}\\)\u003c/span\u003e\u003c/span\u003e \u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e, where Ex is the exposure to the pollutant (mg / (kg‧d)), and RfD is the reference dose of the chemical (mg / (kg‧d)\u003csup\u003e36\u003c/sup\u003e .\u003c/p\u003e\u003cp\u003eConsidering the Provisional Tolerable Weekly Intake (PTWI) for methylmercury (MeHg) of 1.6 \u0026micro;g/kg of human body weight (HBW), as established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) \u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e, the maximum weekly intake of canned tuna (in grams per week) was estimated using the following equation: Intake(g)\u0026thinsp;=\u0026thinsp;PTWI\u0026times;HBW/Cx. Where \u003cem\u003eCx\u003c/em\u003e is the average concentration of MeHg (mg/kg) determined for each canned tuna brand in this study. For the purposes of this calculation, the HBW was set at 70 kg for adults and 14.5 kg for children.\u003c/p\u003e\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003eData analysis\u003c/h2\u003e\u003cp\u003eTo calculate descriptive statistics (mean, standard deviation, range, and recovery), Excel 2016 was used. Boxplots and Chebyshev's theorem\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e were used to evaluate data distribution; the latter was implemented using R software. THg content between the three different canned tuna brands was assessed using non-parametric methods (Kruskall Wallis) followed by a pairwise Wilcox test.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003e\u003cb\u003eQuantification of total mercury content\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFood safety authorities have established various regulations and guidelines to control Hg levels in canned tuna meat to protect public health. These regulations vary by country and organization but generally aim to limit mercury exposure from tuna consumption. The EU, in Regulation (EC) No. 629/2008, set the maximum level of Hg allowed in predatory species at 1.0 mg/kg w/w and 0.5 mg/kg w/w for other fish species, while the US Food and Drug Administration (FDA) set the level for tuna at 1.0 mg/kg; however, the US EPA set 0.5 mg/kg w/w as the level safe for human consumption. On the other hand, the Canadian Food Inspection Agency (CFIA) established 0.5 mg/kg w/w as the maximum for canned tuna and 1.0 mg/kg w/w for fresh/frozen tuna \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Considering the maximum tuna Hg levels set by the EU, US, and CFIA, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, shows that none of the tuna brands exceeded the established thresholds. However, the Hg limits for canned albacore, specifically canned white and light tuna (\u003cem\u003eskipjack tuna\u003c/em\u003e), established by the FDA in 2008 (FDA Website 2008) are 0.035 mg/kg and 0.0112 mg/kg, respectively. Considering these limits, all brands far exceeded these concentrations. Nevertheless, according to the Ecuadorian National Fisheries Institute, these species are not used in Ecuadorian canned tuna products, but it remains a cause for concern.\u003c/p\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\u003eTotal mercury levels\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (mg\u0026middot;kg\u003csup\u003e-\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e w.w.) in the three brands of canned tuna analyzed per every year of the studied period.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eTotal mercury levels (mgkg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBrand A\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003eBrand B\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003eBrand C\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e\u003cp\u003e(0.05\u0026ndash;0.40)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10\u003c/p\u003e\u003cp\u003e(0.48\u0026ndash;0.89)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e\u003cp\u003e(0.14\u0026ndash;0.61)\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\u003eAccording to the boxplot analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), the data distribution for Brand B was negatively skewed, as the mean was greater than the median and the mode; while for Brand C, the distribution was positively skewed. For brand A, the distribution was symmetric because the mean and median are very close (Gaussian behavior). For brand B, 75% of the data indicated that the THg content was between 0.482 and 0.665 mg/kg; for brand A, the content was between 0.045 and 0.225 mg/kg and for brand C, between 0.14 and 0.50 mg/kg. Brand B, which corresponds to the intermediate price in the Ecuadorian market, had an average THg value of 0.6294 mg/kg and was therefore the closest to exceeding the Ecuadorian limit of 0.5 mg/kg; Brand A, which sold at the lowest price on the market, had the lowest THg content. For the brand with the highest market price, an intermediate THg content level was found compared to the other two brands.\u003c/p\u003e\u003cp\u003eKruskal-Wallis test revealed statistically significant differences in total mercury (THg) concentrations among the three canned tuna brands analyzed (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Subsequent pairwise comparisons using the Wilcoxon test indicated that brand B's THg levels were significantly different from those of brands A and C. This distinction appears to be influenced by two specific batches from brand B that exhibited the highest THg concentrations. The p-values for brands A, B, and C were 0.1228, 0.3788, and 0.4035, respectively, according to the Kruskal-Wallis test.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eChebyshev\u0026rsquo;s theorem was applied to estimate the confidence intervals and assess the degree of dispersion within each dataset. This theorem allows for calculating the minimum proportion of population values that lie within \u003cem\u003ek\u003c/em\u003e standard deviations from the mean using the expression \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:(1-\\frac{1}{{k}^{2}})\\)\u003c/span\u003e\u003c/span\u003e, ​ and conversely, the maximum proportion of values falling outside this range using (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{1}{{k}^{2}}\\)\u003c/span\u003e\u003c/span\u003e), where \u003cem\u003ek\u003c/em\u003e represents the number of standard deviations and must be greater than 1. In Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the confidence intervals were computed using specific \u003cem\u003ek\u003c/em\u003e values: π, φ, and \u003cem\u003ee\u003c/em\u003e, which were chosen for their relevance in modelling natural and artificial systems\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. When \u003cem\u003ek\u003c/em\u003e was set to π (3.1416), Chebyshev\u0026rsquo;s theorem predicted that at least 89.87% of the data fell within that range from the mean. For \u003cem\u003ee\u003c/em\u003e (2.72), the corresponding coverage was 86.47%, and for φ (1.618), it dropped to 61.80%. Moreover, the results shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e indicate that brand C exhibits the widest confidence interval among the analyzed brands. According to Chebyshev\u0026rsquo;s theorem, if new observations are added to the population of brand C, there is an 89.87% likelihood (with \u003cem\u003ek\u003c/em\u003e\u0026thinsp;=\u0026thinsp;π) that these new data points will fall within π standard deviations of the mean. This supports the conclusion that brand C consistently presents intermediate THg levels compared to brands A and B, with a higher degree of statistical confidence.\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e compares this study\u0026rsquo;s results to those in the literature published. The THg values fall within the ranges reported by most of the previous studies, with the exception of those for samples from Mexico\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e, suggesting a potential violation of the permissible Hg limit for canned products in this region.\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\u003eConfidence intervals, according to uncertainties about the distribution of the data, obtained from \u003cem\u003eChebyshev\u003c/em\u003e's theorem\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eStandard Deviations\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eMinimum % within\u003c/p\u003e\u003cp\u003e[1-(1/k\u003csup\u003e2\u003c/sup\u003e)]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMax % outside\u003c/p\u003e\u003cp\u003e[1/k\u003csup\u003e2\u003c/sup\u003e]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBrand A\u003c/p\u003e\u003cp\u003econfidence interval\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eBrand B\u003c/p\u003e\u003cp\u003econfidence\u003c/p\u003e\u003cp\u003einterval\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eBrand C\u003c/p\u003e\u003cp\u003econfidence interval\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eπ (3.141593)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.8987\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003e0.1013\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e(-0.16769, 0.2870796)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e(-0.227532,0.674699)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e(-0.05291418,0.4118852)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003e\u003cem\u003ee\u003c/em\u003e (2.71828)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.8647\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003e0.1353\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e(-0.152221,0.302559)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e(0.2427424,0.6899189)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e(-0.03710402,0.4277052)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eφ (1.618034)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.6180\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u003cp\u003e0.3197\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e(-0.040059,0.386385)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e(0.3530297, 0.7723444)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e(0.07753211,0.5133809)\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\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eStudies on THg content in canned tuna in water and oil performed in other countries.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eType of preserved canned\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCity / Country of study\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eOrigin of samples\u003c/span\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eSpecies\u003c/span\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTechnique\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eMean \u003cem\u003eTotal Hg\u003c/em\u003e\u003c/p\u003e\u003cp\u003e(mg\u0026middot;kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eReferences\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNew Jersey, Unites States\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eUnited States\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eThunnus germo\u003c/em\u003e and \u003cem\u003eKatsuwonus pelamis\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold Vapor Atomic Absorption Spectrophotometry (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.096 to 0.431\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e42\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLower Austria, Burgenland and from Viennese retail operations\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDifferent brand\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e43\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLas Vegas, Unites States\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAtomic Absorption Mercury Analyser (AMA)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.541 to 0.714\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e44\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTyrrhenian Sea\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAtomic absorption spectroscopy (AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.04 to 1.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water and oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMazatl\u0026aacute;n, Mexico\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMexico\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eThunnus albacares\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold Vapor Atomic Absorption Spectrophotometry (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.25 to 0.51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOlive oil, sunflower seed oil, water or marinade\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eThe most popular brands in Spain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eYellowfin, bigeye tuna, and skipjack tuna\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAtomic absorption spectrometry and thermal decomposition amalgamation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eItaly, Libya, Spain and Thailand\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDifferent brand origin and country of manufacture\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna skipjack and yellowfin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect Mercury Analyzer (DMA)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.163\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e47\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSpain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eThunnus albacares\u003c/em\u003e and \u003cem\u003eThunnus alalunga\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInductive Coupled Plasma-Mass Spectrometry (ICP-MS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.332\u0026thinsp;\u0026plusmn;\u0026thinsp;0.151\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e39\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSao Paulo, Brazil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eThermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.044 to 0.402\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSao Paulo, Brazil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eThermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.051 to 0.460\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eVojvodina, Serbia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eThailand, Vietnam, Indonesia and Spain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInductive Coupled Plasma-Mass Spectrometry (ICP-MS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.007 to 0.640\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e49\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePortugal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCaught by commercial vessels from the Eastern Central Atlantic Ocean\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eSkipjack tuna\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eThermal Decomposition, Amalgamation and Atomic Absorption Spectrometry (TDA- AAS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.134\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCartagena, Colombia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eEcuador and Colombia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect Mercury Analyzer (DMA)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001 to 0.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCartagena, Colombia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSupermarkets located in Cartagena (10\u0026deg;25\u0026prime;25\u0026Prime;N 75\u0026deg;31\u0026prime;31\u0026Prime;W) on Colombia\u0026rsquo;s northern coast\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect Mercury Analyzer (DMA)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026sim;0.610\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIran\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePurchased from 10 different markets in Tehran\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eThunnus albacares, (Clupeonella cultriventris caspia, Euthynnus affinis, Thunnus tonggol\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInductively coupled plasma optical emission spectrometry (ICP-OES\u0026nbsp;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEcuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold\u003c/p\u003e\u003cp\u003evapour atomic absorption spectrophotometry (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.022 to 0.093\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSerbian\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCoupled Plasma-Mass Spectrometry (ICP-MS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.03 to 0.068\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e54\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eShredded in vegetable oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBarranquilla, Colombia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eChina, Ecuador, and Colombia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eThunnus albacares\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold Vapor Atomic Absorption Spectrophotometry (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.1311 to 1.4725\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eIran\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePersian Gulf\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAtomic Absorption Spectrometer (FAAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e177\u0026ndash;315,3 ppb\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTijuana, Mexico\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eThunnus albacares\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold Vapor Atomic Absorption Spectrophotometry (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.005 to 1.17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e56\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eItaly\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDifferent brands sold in different markets\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eStandard methods: EN 13805:2014\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.207\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eItaly\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eItalian market\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAtomic absorption spectroscopy (AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.041\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water and oil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eEcuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eEastern Pacific international waters\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eKatsuwonus pelamis, Thunnus albacares, and Thunnus tuna\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold vapor atomic absorption\u003c/p\u003e\u003cp\u003eSpectroscopy (CV-AAS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u0026sim; 0.043\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFoggia, Italy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eNot specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eInductive Coupled Plasma-Mass Spectrometry (ICP-MS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.207\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQuito, Ecuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eEcuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCold Vapor Atomic Fluorescence Spectrophotometry (CV-AFS)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.02 to 1.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConserved in water\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQuito, Ecuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eEcuador\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTuna not specified\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eDirect Mercury Analyzer (DMA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.22 to 0.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eThis study\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\u003eRegarding the medium in which the tuna is preserved inside the cans, the results indicate no a priori difference in THg content between samples of the same brands preserved in water, according to the report by Aguilar-Miranda et al.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e, and those preserved in oil, according to the present study. The possible differences between these results and those from the studies presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e may be due to differences in species, size, fish lifespan, and capture site. For example, according to Farrell Anthony \u003csup\u003e\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e\u003c/sup\u003e, skipjack tuna (\u003cem\u003eKatsuwonus pelamis\u003c/em\u003e), which is highly popular in terms of fishing and represents 58% of global tuna catch\u003csup\u003e\u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e66\u003c/span\u003e\u003c/sup\u003e, has a shorter lifespan and therefore accumulates less Hg in its tissues. \u003cem\u003eThunnus alalunga\u003c/em\u003e reaches a maximum weight of approximately 40 kg at 15 years old, while \u003cem\u003eKatsuwonus pelamis\u003c/em\u003e has a maximum weight of approximately 30 kg at the same age.\u003c/p\u003e\u003cp\u003eConsidering the widespread consumption of canned tuna globally and the potential Hg-related side effects for human health, the species, size, and catch location should be required and regulated on labels. In this regard,Shim et al. \u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003esuggested that, because of young children\u0026rsquo;s susceptibility to Hg\u0026rsquo;s toxic effects, products with low metal concentrations should be specially labeled as \u0026ldquo;safe for children\u0026rdquo;; they proposed that the maximum Hg content for commercial fish be reduced to 0.185 mg/kg. Generally, this information is confusing or insufficient on such labels and limits a more consistent assessment when comparing results between different regions. Since December 13, 2014, the EU has implemented changes in the regulations for labeling all fishery and aquaculture products. For products such as canned fish, information on the capture zone shown in the barcodes is voluntary, unlike for unprocessed fish products, for which the capture zone must be specified; however, many retailers have chosen to provide this information \u003csup\u003e\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e\u003c/sup\u003e. In Ecuador, the labels on this type of product only provide nutritional information. Given the widespread consumption of canned tuna and the potential health risks, it is recommended that product labels include information on species, size, and catch location. In this context, Shim et al. \u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e proposed that products with low Hg levels should be specially labeled as \u0026ldquo;safe for children.\u0026rdquo; However, in Ecuador, labeling for these products currently only includes nutritional information.\u003c/p\u003e\u003cp\u003e\u003cb\u003eHuman health risk assessment\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn marine environments, inorganic Hg passes through biological membranes and transforms into Me-Hg, which could be an indication of a biomagnification process of Hg in the food web, given that Me-Hg is highly lipophilic. The study methodology used allowed THg values to be measured only in the samples. However, the literature has suggested that, depending on the species, particularly for fish such as tuna, when analyzing muscle tissue, Me-Hg constitutes a significant percentage of THg content, ranging from 80 to 100% in some cases \u003csup\u003e\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the results obtained of the exposure levels, potential non-carcinogenic risk, and recommended weekly intake of fish meat, for children and adults, based on mean content of THg found in the three brands of canned tuna in oil. The level of exposure to THg (Ex) calculated, in none of the brands exceed the FDA reference dose of 0.1 mg/kg day BW\u003csup\u003e-1 62,\u003cspan citationid=\"CR63\" class=\"CitationRef\"\u003e63\u003c/span\u003e\u003c/sup\u003e. However, for an adult weighing 70 kg and a child weighing 14.5 kg, the non-carcinogenic potential risk (Rx) values were greater than or close to 1 for Brand C, 1.4 and 0.6, respectively, suggesting that consuming tuna from this brand poses a health risk.\u003c/p\u003e\u003cp\u003eBased on these results, the recommended weekly intake of fish meat for children and adults was calculated. According to the FDA/EPA, 2022,\u003csup\u003e\u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e64\u003c/span\u003e\u003c/sup\u003e the highest allowable THg concentration in fish when eating 1 serving per week is 0.46 mg kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The suggested weekly consumption values, calculated from the highest THg concentration found for each brand for children (body weight 14.5 kg) and adults (body weight 70 kg), were 106 and 512 g fish/week for brand A; 26 and 126 g fish/week for brand B; and 64 and 307 g fish/week for brand C, respectively. These results suggest that consuming canned tuna in oil in higher quantities could have negative consequences for human health. Brand A allows for the highest weekly consumption. Consuming more than six 80g can of tuna with a higher Hg content per week may pose a risk to Ecuadorian consumers.\u003c/p\u003e\u003cp\u003eAccording to Ormaza et al. \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, canned tuna in Ecuador is consumed once or twice a week, although not consistently. Assuming a weekly portion of 80 g for adults and 40 g for children (half a can), the non-carcinogenic risk index (Rx) calculated for the average THg concentration in brand C exceeds 1. This suggests a significant potential risk when consuming more than one portion per week, particularly for vulnerable populations such as pregnant women and children. For brands A and B, the risk is lower, though children remain more vulnerable than adults do. In other countries, such as Mexico, studies have reported low non-carcinogenic risks associated with canned tuna consumption; however, consumption levels vary greatly. For example, average daily tuna intake is 3.92 g in Mexico and 5.71 g in Italy, while in Ecuador; the estimated daily fish consumption is 37.0 g, though it's not specified whether this includes canned tuna. Therefore, frequent consumption of tuna or other fish species should be a health concern.\u003c/p\u003e\u003cp\u003eThe estimated risk of THg exposure, using the hazard quotient (HQ) value and mean concentration of Me-Hg (0.80xTHg) in the samples\u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e, was much higher than 1 for all brands (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), indicating possible adverse health effects for consumers. Similarly, using the calculated mean Me-Hg concentration in each sample, the Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the recommended maximum allowable rate of consumption of tuna in meals/week, CRmw\u003csup\u003e\u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e65\u003c/span\u003e\u003c/sup\u003e. This is also graphically presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e as HQ \u003cem\u003evs.\u003c/em\u003e CRmw; the results confirm that indeed the brand A could be consumed in a greater number of meals per week.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eExposure levels, potential non-carcinogenic risk, and recommended weekly intake of fish meat for children and adults, based on mean content of MeHg found in the three brands of canned tuna in water.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"21\"\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\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c16\" colnum=\"16\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c17\" colnum=\"17\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c18\" colnum=\"18\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c19\" colnum=\"19\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c20\" colnum=\"20\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c21\" colnum=\"21\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c2\" namest=\"c1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"6\" nameend=\"c8\" namest=\"c3\"\u003e\u003cp\u003eBrand A\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c14\" namest=\"c12\"\u003e\u003cp\u003eBrand B\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c16\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c19\" namest=\"c17\"\u003e\u003cp\u003eBrand C\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e\u003cb\u003eEx\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(mg kg\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eday BW\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e\u003cb\u003eRx\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e\u003cb\u003eRecommended\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eweekly intake\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(g fish/week)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003eHQ\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003eCRmw\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c12\"\u003e\u003cp\u003e\u003cb\u003eEx (mg\u0026middot;kg\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eday BW\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c13\"\u003e\u003cp\u003e\u003cb\u003eRx\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c14\"\u003e\u003cp\u003e\u003cb\u003eRecommended\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eweekly intake\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(g fish/week)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c15\"\u003e\u003cp\u003e\u003cb\u003eHQ\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c16\"\u003e\u003cp\u003e\u003cb\u003eCRmw\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c17\"\u003e\u003cp\u003e\u003cb\u003eEx (mg\u0026middot;kg\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e \u003cb\u003eday BW\u003c/b\u003e\u003csup\u003e\u003cb\u003e\u0026minus;\u0026thinsp;1\u003c/b\u003e\u003c/sup\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c18\"\u003e\u003cp\u003e\u003cb\u003eRx\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c19\"\u003e\u003cp\u003e\u003cb\u003eRecommended\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eweekly intake\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(g fish/week)\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c20\"\u003e\u003cp\u003e\u003cb\u003eHQ\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c21\"\u003e\u003cp\u003e\u003cb\u003eCRmw\u003c/b\u003e\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eChildren\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e8.62 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e0.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e106\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e9.65\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e19.32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e2.48 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cp\u003e2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cp\u003e27.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e6.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u003cp\u003e1.44 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c18\"\u003e\u003cp\u003e1.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u003cp\u003e64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u003cp\u003e16.10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u003cp\u003e11.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAdult\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e3.57 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u003cp\u003e0.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e\u003cp\u003e512\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e1.99\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e4.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1.03 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c14\"\u003e\u003cp\u003e126\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c15\"\u003e\u003cp\u003e5.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c16\"\u003e\u003cp\u003e1.39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c17\"\u003e\u003cp\u003e5.90 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c18\"\u003e\u003cp\u003e0.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c19\"\u003e\u003cp\u003e307\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u003cp\u003e3.34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u003cp\u003e2.40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"12\" nameend=\"c19\" namest=\"c8\"\u003e\u003cp\u003e*PTWI (\u0026micro;g MeHg\u0026middot;kg\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e HBW): 1.6\u003c/p\u003e\u003cp\u003e\u003csup\u003ea\u003c/sup\u003e Body weight of 14.5 kg for children; \u003csup\u003eb\u003c/sup\u003e Body weight of 70 kg for adults\u003c/p\u003e\u003cp\u003e*Hazard quotient (HQ)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c20\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c21\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eAmong the three canned tuna, brands analyzed, also among the most consumed in Ecuador, brand B exhibited the highest THg concentration, reaching up to 0.63mg kg⁻\u0026sup1;. Despite this, the majority of samples from brands A, B, and C presented THg levels below the maximum limits established by national and international food safety standards. The observed variability in THg concentrations among brands can likely be explained by factors such as the species, size, age, fat content of the fish, and environmental conditions of the capture area. Mercury accumulation in tuna is known to depend on ecological parameters including the degree of aquatic pollution, geographic origin, and seasonal variation at the time of capture.\u003c/p\u003e\u003cp\u003eRisk assessment based on the estimated MeHg intake (Rx) indicated that consuming a single weekly serving of 80 g for adults and 40 g for children does not represent a significant non-carcinogenic health risk. However, increasing portion size or consumption frequency may pose a greater risk for vulnerable groups, especially children, due to their lower body weight and developing systems. While fish intake is nutritionally beneficial, its consumption must be balanced to minimize potential mercury exposure.\u003c/p\u003e\u003cp\u003eGiven the potential health implications, particularly for pregnant women and children, it is strongly recommended to implement national strategies for routine monitoring of mercury levels in canned tuna and other commonly consumed fish products. Additionally, Ecuador\u0026rsquo;s regulatory framework should mandate the labeling of tuna species and catch origin on packaging, as these factors are critical for assessing risk. Improved labeling would empower consumers to make informed choices and avoid species known for higher mercury accumulation.\u003c/p\u003e\u003cp\u003eThis study provides relevant evidence on THg levels in the most widely consumed canned tuna brands in the Ecuadorian market, highlighting the need to strengthen food safety monitoring and surveillance systems. Although risk assessment for MeHg exposure suggests that occasional consumption within recommended portion sizes does not pose a significant threat to the adult population, cumulative exposure in vulnerable groups such as children and pregnant women may present a public health concern. Therefore, it is imperative to promote policies that support sustainable fishing practices, improved labeling standards, and public education campaigns aimed at encouraging safe and informed fish consumption across the country.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflicts of interest\u003c/h2\u003e\u003cp\u003eThere are no conflicts of interest to declare.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eETC: data curation and methodology; LF: contributed to funding acquisition, conceptualisation, data curation, formal analysis, methodology, project administration, supervision and writing; NCS: contributed to data acquisition, data curation, methodology and supervision; MRU: contributed to data acquisition, data curation and methodology; EOMM: contributed to formal analysis; DBM: contributed to data curation and methodology; PEM: contributed to data curation and writing.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eThe authors of this research thank the Research Directorate of the Pontificia Universidad Cat\u0026oacute;lica del Ecuador for their funding.\u003c/p\u003e\u003ch2\u003eData availability\u003c/h2\u003e\u003cp\u003eData \u0026ldquo;available on request\u0026rdquo;: [email protected]\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZuleta, L., Becerra, A., 2013. 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Washington, DC.\u003c/span\u003e\u003c/li\u003e\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":"npj-science-of-food","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"npjscifood","sideBox":"Learn more about [npj Science of Food](http://www.nature.com/npjscifood/)","snPcode":"41538","submissionUrl":"https://submission.springernature.com/new-submission/41538/3","title":"npj Science of Food","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7160559/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7160559/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMercury is a toxic chemical present in seafood due to its bioaccumulative nature. Given the frequent consumption of these food products, it is important to know the amount of mercury present in these products so that they can be ingested without triggering adverse health effects for consumers. Therefore, this study quantified total Hg in samples of canned tuna in oil from supermarkets in the Metropolitan District of Quito, Ecuador. Three brands of tuna were analyzed; these were coded as A, B, and C, according to their market price (A\u0026thinsp;\u0026lt;\u0026thinsp;B\u0026thinsp;\u0026lt;\u0026thinsp;C). After analysis using a direct mercury analyzer, total Hg concentrations were 0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10 mg/kg; 0.63\u0026thinsp;\u0026plusmn;\u0026thinsp;0.10 mg/ kg; and 0.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 mg/kg for A, B, and C, respectively. Results indicated that total Hg content of the different brands was within the permissible limits established by surveillance regulations. However, the potential non-cancer risk of methylmercury for consumers of brand C exceeded the limit (\u0026gt;\u0026thinsp;1) established by the US Environmental Protection Agency. Using the highest total Hg concentration to which the Ecuadorian population is exposed through the consumption of brands A, B and C, for children (body weight 14.5 kg) and adults (body weight 70 kg), the following recommended weekly intake (g of fish/week) was determined for each brand: A: 106 and 512 g; B: 26 and 126 g; C: 64 and 307 g, respectively.\u003c/p\u003e","manuscriptTitle":"Total mercury exposure through canned tuna in oil sold in Quito, Ecuador","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-01 15:16:27","doi":"10.21203/rs.3.rs-7160559/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-07T11:56:24+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-07T10:21:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"192613427476705499943213224745034583530","date":"2025-10-07T10:14:42+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-17T17:37:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"209567756315048348106214218433819956922","date":"2025-09-17T15:31:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-28T18:39:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-27T21:08:23+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-24T14:03:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"npj Science of Food","date":"2025-07-18T20:32:38+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-science-of-food","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"npjscifood","sideBox":"Learn more about [npj Science of Food](http://www.nature.com/npjscifood/)","snPcode":"41538","submissionUrl":"https://submission.springernature.com/new-submission/41538/3","title":"npj Science of Food","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0019da25-4edc-4f68-bba7-78754ab52f0a","owner":[],"postedDate":"August 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":52256867,"name":"Biological sciences/Ecology"},{"id":52256868,"name":"Earth and environmental sciences/Ecology"},{"id":52256869,"name":"Earth and environmental sciences/Environmental sciences"}],"tags":[],"updatedAt":"2026-01-19T16:45:27+00:00","versionOfRecord":{"articleIdentity":"rs-7160559","link":"https://doi.org/10.1038/s41538-025-00693-4","journal":{"identity":"npj-science-of-food","isVorOnly":false,"title":"npj Science of Food"},"publishedOn":"2026-01-12 16:29:12","publishedOnDateReadable":"January 12th, 2026"},"versionCreatedAt":"2025-08-01 15:16:27","video":"","vorDoi":"10.1038/s41538-025-00693-4","vorDoiUrl":"https://doi.org/10.1038/s41538-025-00693-4","workflowStages":[]},"version":"v1","identity":"rs-7160559","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7160559","identity":"rs-7160559","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}