Bioaccumulation and Health Risk Assessment of Heavy Metals in Commercial Fish from the Red Sea, Saudi Arabia

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L. Alharbi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8554945/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study investigated the bioaccumulation of trace elements Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr), Iron (Fe), Nickel (Ni), Copper (Cu), Vanadium (V), Manganese (Mn), and Zinc (Zn) in three commercially significant fish species ( Sardinella longiceps , Herklotsichthys spp. , and Carangoides spp. ). A total of 461 fish samples were collected from four major coastal cities along the Saudi Arabian Red Sea: Umluj, Yanbu, Qunfudah, and Jazan. Metal concentrations were analyzed in both gill and muscle tissues using ICP-MS. Results indicated that essential elements (Fe, Zn, Cu) were generally within safety limits; however, a significant geographic gradient was observed. Jazan emerged as a critical hotspot, with As and Cr levels exceeding FAO/WHO maximum permissible limits in muscle tissue. Statistical analysis (Mann-Whitney U) confirmed that gills sequestered significantly higher concentrations of Mn, Zn, and Fe ( p < 0.05 ) than edible muscles. Human health risk assessments, including Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), and Hazard Index (HI), remained below threshold levels ( < 1.0 ), suggesting no immediate non-carcinogenic threat. However, the Target Cancer Risk (TR) for Arsenic in Jazan (1.15×10 − 4 ) slightly exceeded the USEPA negligible risk threshold. These findings identify a distinct north-south pollution gradient, with Jazan representing a priority area for monitoring due to elevated As and Cr levels and a non-negligible carcinogenic risk from arsenic. The low contamination in Umluj provides a valuable regional baseline. Heavy metals Bioaccumulation Fish species Health risk assessment Red Sea Environmental monitoring Figures Figure 1 1. Introduction Heavy metal contamination in marine ecosystems is a persistent global concern because these elements are toxic, non-biodegradable, and prone to bioaccumulation and biomagnification along aquatic food webs. [ 1 – 3 ]. Coastal zones, which host dense human populations and intensive industrial, agricultural, touristic, and maritime activities, are particularly vulnerable to heavy metal inputs from domestic effluents, petrochemical industries, desalination plants, shipping, and urban runoff. [ 2 – 6 ]. Once released, metals such as Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr), Iron (Fe), Nickel (Ni), Copper (Cu), Vanadium (V), Manganese (Mn), and Zinc (Zn) can partition into seawater and sediments, acting as long-term sources for uptake by benthic and pelagic organisms [ 1 , 3 , 6 – 8 ]. Numerous studies have shown that marine fish and shellfish accumulate these metals in their tissues, sometimes at levels posing non-carcinogenic and carcinogenic risks to consumers, especially children and high-intake groups [ 9 – 13 ]. Seafood is widely promoted as a nutrient-dense food, rich in high-quality protein and omega-3 fatty acids, and is a significant component of diets in many coastal countries [ 14 – 16 ] This nutritional benefit can be offset when seafood is contaminated by toxic metals such as As, Cd, Hg, and Pb, which have been associated with neurotoxicity, nephrotoxicity, developmental impairment, and increased cancer risk [ 1 , 10 , 11 , 17 – 20 ]. Recent regional and global assessments indicate that arsenic and mercury are often the dominant contributors to health risk from seafood consumption, with Cd and Pb also of concern in specific locations and species. [ 9 – 11 , 21 , 22 ]. These findings have driven international efforts by the WHO, FAO, EFSA, and national agencies to establish maximum permissible levels for key metals in seafood and to emphasize continuous monitoring and risk assessment. [ 1 , 10 , 14 , 15 , 19 ]. The Red Sea is a semi-enclosed, oligotrophic basin of exceptional biodiversity and economic importance, supporting fisheries, tourism, shipping, and intensive coastal development, particularly along the Saudi coastline [ 1 , 2 , 23 ]. Rapid urbanization, expansion of petroleum and petrochemical industries, cement production, ports, and desalination facilities have markedly increased anthropogenic metal inputs to this region [ 1 , 2 , 4 – 6 , 12 ]. Studies on Red Sea sediments, seawater, mangroves, and biota have documented elevated and spatially heterogeneous levels of Cd, Pb, Zn, Cu, Ni, and other metals, with the highest burdens typically near industrialized and urbanized hubs such as Jeddah, Rabigh, Hurghada, and Yanbu [ 1 , 2 , 4 – 8 , 24 , 25 ]. Ecological and human-health risk assessments based on sediments and water generally indicate localized considerable to very high environmental risk, particularly for Cd and Pb, and highlight the need for continuous monitoring and source control [ 1 , 6 , 7 , 19 , 20 , 26 ]. Despite this growing body of work, there are still comparatively few integrated assessments of multi-element contamination directly in commercially important Red Sea seafood, especially along the western Saudi coast. Most existing studies focus on sediments, mangroves, or limited suites of metals in selected fish species, and data for combined fish–crab matrices across multiple coastal cities remain sparse [ 1 , 2 , 5 , 6 , 8 ]. Given the heavy reliance of coastal communities on local fisheries in cities such as Yanbu, Al Qunfudhah, and Jazan, there is a clear need to quantify the burden of a broad range of potentially toxic elements in edible marine species and to compare these burdens among sites that differ in the intensity of industrial and urban development. The present study addresses three key gaps: Determine the concentrations of various metals, including Cr(III), Hg(II), Pb(II), Mn(II), As(III), Cd(II), Ni(II), V(III), Cu(II), Fe(II), and Zn(II), in the gills and muscles of three fish species: Sardinella longiceps, Carangoides spp., and Herklotsichthys spp . Comparing tissue-specific and site-specific accumulation patterns against international guideline values, this study provides new evidence regarding the status of metal contamination in Red Sea seafood. Contribute to the regional database necessary for risk assessment and the sustainable management of coastal resources. 2. Materials and Methods 2.1. Study Area and Sample Collection Fish samples, including various fish species ( Sardinella longiceps, Carangoides spp., Herklotsichthys spp .), were collected from four well-characterized locations in the western Red Sea of Saudi Arabia, specifically Umluj, Yanbu, Qunfudhah, and Jazan. The fish samples were purchased from local fishermen immediately after landing at all sites. Species were identified morphologically using standard taxonomic keys based on external characters (body shape, coloration, fin morphology, and meristic counts). Questionable specimens were verified by an ichthyology expert. These species are the staple fish for the Saudi Arabian population along the Red Sea coast. Fish samples were collected between September 2023 and January 2024 (Table 1 ). Following collection, samples were transported to the laboratory in insulated ice chests and stored at -40°C until dissection and analysis. The geographical coordinates and sampling locations are illustrated in Fig. 1 . Table 1 Summary of Diet, Habitat, and Sample Sizes for Studied Fish Species Species Primary Diet Habitat Preference No of samples Indian Oil Sardine ( Sardinella longiceps ) Phytoplankton & Zooplankton Coastal-pelagic; prefers upwelling zones. 180 Trevallies / Jacks ( Carangoides spp. ) Small fish, Crustaceans, Squid Reef-associated; bays and rocky outcrops. 140 Bluestripe Herring ( Herklotsichthys quad. ) Zooplankton (nocturnal) Shallow lagoons and mangroves. 141 Table 2 Biometric data of Sampling Site Locations, Collection Periods, and Sample Sizes. City Coordinates Collection Date Species Avg. Length (cm) Avg. Weight (g) No of samples Umluj 25.20° N, 37.2° E Oct 2023 Sardinella longiceps 15–20 40–90 35 Carangoides spp. 25–35 300–600 28 Herklotsichthys quad. 10–13 25–45 36 Yanbu 24.07° N, 38.05° E Sept 2023 Sardinella longiceps 15–20 40–90 45 Carangoides spp. 25–35 300–600 33 Herklotsichthys quad. 10–13 25–45 30 Qunfudah 19.03° N, 41.16° E Jan 2024 Sardinella longiceps 15–20 40–90 51 Carangoides spp. 25–35 300–600 44 Herklotsichthys quad. 10–13 25–45 42 Jazan 17.04° N, 42.46° E Jan 2024 Sardinella longiceps 15–20 40–90 49 Carangoides spp. 25–35 300–600 35 Herklotsichthys quad. 10–13 25–45 33 Total of samples 461 2.2. Sample Preparation and Acid Digestion Target tissues (muscle and gills) were dissected with stainless steel instruments, rinsed with deionized water, and homogenized. Approximately 0.50 g (dry weight) of each tissue sample was weighed into a 250 mL acid‑washed glass beaker. A digestion mixture of 12 mL concentrated HNO₃ (69%) and 6 mL H₂O₂ (30%) was added to each sample. The beakers were covered with watch glasses and heated on a hot plate at 140°C for 1.5–2 hours, until all organic matter was completely oxidized and the digest became clear, following a previously validated protocol by Alharbi et al. (2018) [ 16 ]. The digests were then cooled to room temperature prior to filtration and dilution. 2.3. Filtration and Elemental Analysis Once cooled, the digestates were filtered through Whatman No. 42 filter paper into volumetric tubes to remove any remaining siliceous material. The solutions were then diluted to a final volume of 50 mL using ultra-pure distilled water. Trace element concentrations were determined using an Agilent 7500 Series ICP MS (Agilent Technologies, USA). The instrument was operated at an RF power of 1550 W, with plasma gas (Ar) flow of 15.0 L min⁻¹, auxiliary gas flow of 1.0 L min⁻¹, and nebulizer gas flow of 0.90 L min⁻¹. The sampling depth was set to 8 mm below the load coil. Helium collision cell mode (He mode) was used to minimize polyatomic interferences for all monitored isotopes. The following isotopes were measured: ⁵¹V, ⁵²Cr, ⁵⁵Mn, ⁵⁷Fe, ⁶⁰Ni, ⁶³Cu, ⁶⁶Zn, ⁷⁵As, ¹¹¹Cd, ²⁰⁸Pb, and ²⁰²Hg. To correct for matrix effects and instrumental drift, ⁷²Ge, ¹¹⁵In, and ²⁰⁹Bi were added online as internal standards at a concentration of 10 µg L⁻¹. The instrument was calibrated using a series of multi-element external standards prepared in the same acid matrix as the samples, covering the expected concentration range for all analytes. Calibration curves were linear (R² > 0.999) for all monitored elements. Instrumental parameters were tuned daily with a multi-element solution to maximize sensitivity and ensure low oxide and doubly charged ion ratios[ 27 ]. 2.4. Quality Control and Statistical Analysis The accuracy of the ICP MS measurements was evaluated using the certified reference material DORM 4 Fish Protein (National Research Council Canada), processed and analyzed under the same digestion and instrumental conditions as the samples. Recoveries for all target elements were within acceptable limits, ranging from 92% for As to 105% for Zn, confirming the accuracy of the method. The limits of detection (LOD) and limits of quantification (LOQ) were calculated as three times (3σ) and ten times (10σ), respectively, the standard deviation of the reagent blank signals analyzed throughout the batch sequence[ 28 ]. Statistical processing was performed using SPSS (Version 26.0) and GraphPad Prism. Before the comparative analysis, the dataset's distribution was evaluated using the Shapiro-Wilk normality test. Because most trace element concentrations deviated from normality ( p < 0.05), nonparametric statistical methods were employed. The following tests were used to interpret the data: Mann-Whitney U Test: used to compare metal concentrations between the two distinct tissue types (Gills vs. Muscle) (Table 10 ). Kruskal-Wallis H Test: Applied to identify significant differences in bioaccumulation across the four sampling locations (Umluj, Yanbu, Qunfudah, and Jazan) and among the three fish species.Dunn’s Post-hoc Test: Conducted following significant Kruskal-Wallis results to pinpoint specific pairs of locations or species that differed significantly.Spearman Correlation Matrix: Utilized to investigate the relationships between different metals and to identify potential familiar sources of contamination. Statistical significance for all tests was determined at a 95% confidence level ( p < 0.05). All data are presented as Mean ± Standard Deviation (SD). 2.5. Health Risk Assessment 2.5.1. Target Hazard Quotient (THQ) The potential non-carcinogenic health risk associated with heavy metal exposure from fish consumption was evaluated using the Target Hazard Quotient (THQ). The THQ is a unitless index developed by the United States Environmental Protection Agency [ 29 ]To estimate the risk level of pollutant exposure. A THQ value less than 1 (unity) indicates that the exposure level is below the reference dose and that there is no significant chronic-toxic risk to consumers. Conversely, a THQ ≥ 1 indicates a potential health concern [ 30 ] The THQ was calculated using the following equation: \(\:THQ=\frac{EF\times\:ED\times\:FIR\times\:CF\times\:CM}{WAB\times\:ATn\times\:RfD}\times\:\) 10 −3 where THQ is the target hazard quotient (unitless); EF is the exposure frequency (365 days/year); ED is the exposure duration (70 years, representing lifetime exposure for non-cancer risk); FIR is the fish ingestion rate (7 g/person/day, as recommended by Ministry of Environment, Water and Agriculture (MEWA, 2023); CF is the conversion factor (0.2) used to convert fresh weight to dry weight, assuming 80% moisture content in fish muscle [ 25 , 31 , 32 ]. CM is the concentration of the metal in fish muscle (mg/kg dry weight); WAB is the average adult body weight (60 kg) [ 33 ]; ATₙ is the averaging time for non-carcinogenic effects, calculated as EF × ED = 25,550 days; RfD is the oral reference dose of the metal (mg/kg/day), representing the maximum daily exposure unlikely to cause adverse non-cancer health effects [ 34 – 36 ]. The RfD values adopted for each metal followed the USEPA guidelines (2024)[ 29 ]. 2.5.2. Hazard Index (HI) In real-world exposure scenarios, consumers are often exposed to multiple trace elements simultaneously. To account for the potential additive effects of these contaminants, the Hazard Index (HI) was employed as a comprehensive measure of the total non-carcinogenic risk (USEPA, 2006). The HI is defined as the arithmetic sum of the individual Target Hazard Quotients (THQs) calculated for each metal in the study. The Hazard Index was calculated using the following equation: $$\:HI=\:\sum\:_{i=1}^{n}THQi$$ Where: HI is the Hazard Index for a specific fish species. THQi represents the Target Hazard Quotient for the IH trace element in the mixture. n is the total number of trace elements evaluated (in this study: V, Cr, Mn, Co, Ni, Zn, As, Fe, Pb, Cu, and Cd). 2.5.3. Target Cancer Risk (TR) For elements classified as potential carcinogens, the Target Cancer Risk (TR) is estimated to represent the incremental probability that an individual will develop cancer over a lifetime due to exposure (USEPA, 1989). While several trace metals were analyzed in this study, Arsenic (As) is specifically identified by the USEPA as a known carcinogen, necessitating a dedicated assessment of its carcinogenic potential (USEPA, 2024) [ 29 ]. The TR for inorganic Arsenic was calculated by multiplying the exposure level by the oral carcinogenic potency slope ( CPSo ), using the following model: \(\:TR=\frac{EF\times\:ED\times\:FIR\times\:CM\times\:CPSo}{WAB\times\:ATn}\times\:\) 10 −3 Where: TR: Target Cancer Risk (unitless probability). CPSo: Carcinogenic Potency Slope, oral (1.5 mg/kg/day) −1 for As [ 29 ]. 2.5.4. Estimated Daily Intake (EDI) The Estimated Daily Intake (EDI) of heavy metals through fish consumption depends on the concentration of the elements in the fish muscle tissue and the quantity of fish consumed daily[ 37 ]. This metric is essential for comparing the actual intake of metals against the Provisional Tolerable Daily Intake (PTDI) set by international health organizations. The EDI was calculated using the following formula: $$\:EDI=\frac{CM\times\:DCfish}{WB}$$ Where: EDI: Estimated Daily Intake of a specific metal (mg/kg body weight/day). DC fish: Daily consumption of fish per capita (7 g/day, as per MEWA, 2023). BW: Average body weight of an adult (60 kg, as per MEWA, 2023). 3. Results 3.1 Identification of Primary Hazard Elements 3.2 Across all four sampling locations and three fish species, As was detected in both gill and muscle tissues at higher risk-based levels than other analyzed metals (Tables 3 and 4 ). In gill tissue, the highest mean As concentration was observed in Qunfudah (0.873 ± 1.41 mg/kg), remaining below the FAO/WHO limit of 1.0 mg/kg, with a range of 0.03–2.51 mg/kg (Table 3 ). Cd, Cr, Mn, Ni, Cu, zinc Zn, Fe, and V in gills were all below their respective FAO/WHO or national limits where such values exist, although Cr approached the upper guideline range in Qunfudah (0.642 ± 1.11 mg/kg; range 0.05–1.92 mg/kg; guideline 0.15–1.0 mg/kg) (Table 3 )[ 38 , 39 ]. Table 3 Highest Mean Concentrations of Heavy Metals in Fish Gills vs. WHO Limits by Location (mg/kg) Heavy Metal Location (Highest Mean) Highest Mean ± SD (mg/kg) Range [Min – Max] (mg/kg) WHO/FAO Limit (mg/kg) As Qunfudah 0.873 ± 1.41 [0.03–2.51] 1.0 Cd Qunfudah 0.033 ± 0.04 [0.003–0.08] 0.05 Cr Qunfudah 0.642 ± 1.11 [0.05–1.92] 0.15–1.0 Fe Jazan 18.00 ± 19.1 [0.06–39.6] 100 Zn Qunfudah 2.548 ± 2.65 [0.56–5.60] 30–40 Cu Yanbu 0.754 ± 1.30 [ND – 2.26] 3.0 Mn Qunfudah 0.463 ± 0.65 [0.08–1.21] 2.5 Ni Yanbu 0.031 ± 0.01 [0.01–0.04] 0.5–0.6 V Qunfudah 1.643 ± 2.77 [ND – 4.84] N/S Table 4 Highest Heavy Metal Concentrations in Fish Muscles vs. FAO/WHO Limits (mg/kg). Heavy Metal Location Mean ± SD [Min – Max] FAO/WHO Limit As Jazan 1.161 ± 1.85 [0.06–3.29] 1 Cd Qunfudah 0.017 ± 0.01 [0.008–0.03] 0.5 Cr Jazan 1.207 ± 2.08 [ND – 3.61] 0.6 Fe Jazan 3.005 ± 4.75 [0.11–8.48] 100 Zn Yanbu 0.125 ± 0.05 [0.08–0.18] 30 Cu Jazan 0.038 ± 0.06 [ND – 0.11] 30 Mn Umluj & Yanbu 0.014 ± 0.00 / 0.01 [0.007–0.02] 0.01 Ni Umluj 0.019 ± 0.01 [ND – 0.03] 0.5 V Jazan 2.145 ± 3.71 [ND – 6.43] N/A In muscle tissue, the highest mean As concentration was recorded in Jazan (1.161 ± 1.85 mg/kg; range 0.06–3.29 mg/kg), with the mean exceeding the FAO/WHO limit of 1.0 mg/kg (Table 4 ). Cr in Jazan muscles also exceeded its guideline value (mean 1.207 ± 2.08 mg/kg; range ND–3.61 mg/kg; guideline 0.6 mg/kg) (Table 4 ). For all sites, mean concentrations of Cd, Fe, Zn, Cu, Mn, Ni, and V in muscle remained below their respective guideline values where available (Table 4 ); no guideline value is specified for V in fish muscle (Table 4 ). The maximum recorded muscle concentration of V occurred in Jazan sardines (6.435 mg/kg, within a site mean of 2.145 ± 3.71 mg/kg; range ND–6.43 mg/kg) (Table 4 ). Essential elements (Fe, Zn, Cu) showed higher absolute concentrations than non-essential toxic metals but remained within their accepted limits in both gill and muscle tissues (Tables 3 and 4 ). 3.3. Regional Risk Profile THQs for As, Cd, Cr, and V, and the corresponding TTHQ, are presented in Table 5 . For all cities and species, individual THQ values for each metal were below 1.0. TTHQ values ranged from 0.00049 (Umluj, Sardinella longiceps) to 0.30628 (Jazan, Sardinella longiceps). The cumulative non-carcinogenic risk, expressed as the Hazard Index (HI), was identical to the TTHQ for each city–species combination because HI was calculated as the sum of THQs for these metals. HI values across cities and species are shown in Table 6 , ranging from 0.00049 to 0.30628, with the highest HI observed for Sardinella longiceps in Jazan and the lowest HI observed for the same species in Umluj. Table 5 Table 5 : Target Hazard Quotients (THQ) and Total THQ (TTHQ) for Studied Fish Species City Species As Cd Cr V TTHQ Umluj Sardinella longiceps 0.00042 0.00004 0.00000 0.00000 0.00049 Herklotsichthys spp. 0.00112 0.00003 0.00000 0.00000 0.00117 Carangoides spp. 0.03034 0.00013 0.00000 0.00000 0.03048 Yanbu Sardinella longiceps 0.00236 0.00006 0.00000 0.00000 0.00243 Herklotsichthys spp. 0.00148 0.00026 0.00000 0.00000 0.00175 Carangoides spp. 0.00338 0.00000 0.00000 0.00000 0.00340 Qunfudah Sardinella longiceps 0.00527 0.00029 0.00000 0.00007 0.00563 Herklotsichthys spp. 0.01692 0.00019 0.00031 0.00015 0.01774 Carangoides spp. 0.07390 0.00075 0.00000 0.00000 0.07468 Jazan Sardinella longiceps 0.25597 0.00039 0.02812 0.02145 0.30628 Herklotsichthys spp. 0.00511 0.00001 0.00000 0.00000 0.00514 Carangoides spp. 0.00978 0.00007 0.00000 0.00000 0.00987 Table 6 Summarizes the cumulative risk (HI) for each species across the four sampling sites, based on the additive THQ values: City Sardinella longiceps Herklotsichthys spp. Carangoides spp. Umluj 0.00049 0.00117 0.03048 Yanbu 0.00243 0.00175 0.00340 Qunfudah 0.00563 0.01774 0.07468 Jazan 0.30628 0.00514 0.00987 TR values for As are summarized in Table 7 . TR values varied by city and species from 1.89 × 10⁻⁷ (Umluj, Sardinella longiceps) to 1.15 × 10⁻⁴ (Jazan, Sardinella longiceps) (Table 7 ). For the remaining city–species combinations, TR values fell between these two extremes, with all values within the 10⁻⁷–10⁻⁴ range (Table 7 ). Table 7 The TR values for the four regions are summarized below: City Sardinella longiceps Herklotsichthys spp. Carangoides spp. Umluj 1.89 ×10 − 7 5.06 ×10 − 7 1.36 ×10 − 5 Yanbu 1.06 ×10 − 6 6.65 ×10 − 7 1.52 ×10 − 6 Qunfudah 2.37 ×10 − 6 7.61 ×10 − 6 3.32 ×10 − 5 Jazan 1.15 ×10 − 4 2.29 ×10 − 6 4.40 ×10 − 6 EDI values for As, Cd, Cr, and V via consumption of Sardinella longiceps are shown in Table 8 . EDI for As ranged from 6.31 × 10⁻⁷ mg/kg bw/day in Umluj to 3.84 × 10⁻⁴ mg/kg bw/day in Jazan (Table 8 ). EDI values for Cd, Cr, and V were lower than those for As at all sites, with Cd ranging from 2.08 × 10⁻⁷ to 1.96 × 10⁻⁶ mg/kg bw/day, Cr from 0 to 4.22 × 10⁻⁴ mg/kg bw/day, and V from 0 to 7.51 × 10⁻⁴ mg/kg bw/day (Table 8 ). Table 8 The calculated EDI values for all metals across Umluj, Yanbu, Qunfudah, and Jazan. City Species As Cd Cr V Umluj S. longiceps 6.31 ×10 − 7 2.08 ×10 − 7 0.00 0.00 Yanbu S. longiceps 3.55 ×10 − 6 2.73 ×10 − 7 0.00 0.00 Qunfudah S. longiceps 7.90 × 10 − 6 1.44 ×10 − 6 0.00 2.44 ×10 − 6 Jazan S. longiceps 3.84 ×10 − 4 1.96 ×10 − 6 4.22 ×10 − 4 7.51 ×10 − 4 Table 9 summarizes the mean concentration ranges of metals in this study, the locations of highest concentrations, corresponding FAO/WHO standards, and qualitative statements from previous studies for comparison. Mean As concentrations in muscle ranged from 0.079 to 0.849 mg/kg, with maximum values up to 3.29 mg/kg in Jazan and Qunfudah; Cr ranged from 0.010 to 0.904 mg/kg (maximum 3.62 mg/kg in Jazan); and Mn exceeded the listed 0.01 mg/kg limit at all locations (0.003–0.500 mg/kg) (Table 9 ). Fe, Zn, Cd, Cu, and Ni remained within their respective FAO/WHO standards, where available (Table 9 ). Table 9 Comparison of Heavy Metal Concentrations and Safety Limits (mg/kg) (w/w) Heavy Metal This Study (Mean Range) Locations of High Concentration [ 40 ] [ 26 ] FAO/WHO Standard As 0.079–0.849 Jazan & Qunfudah (Max: 3.29) Reported as a primary health risk factor Dominant contributor to carcinogenic risk 1 Cr 0.010–0.904 Jazan (Max: 3.62) Often exceeds limits in coastal species Present in multi-metal mixtures 0.6 Mn 0.003–0.500 Yanbu & Qunfudah (Exceeds limit in all) Linked to industrial runoff in ports Found at elevated levels in sediments 0.01 Fe 0.080–10.77 Jazan (Max: 39.6 in Gills) Highly accumulated in internal organs The most accumulated element in Nuweiba 100 Zn 0.029–1.924 Qunfudah (Max: 5.60 in Gills) High levels found in reef-associated fish Dominant metal in fish muscle profiles 30 Cd 0.005–0.024 Low across all sites Low burdens are generally reported Within regulatory limits for the region 0.5 Cu 0.0004–0.585 Yanbu (Max: 2.26 in Gills) Generally, within safety limits Within safety limits for human consumption 30 Ni ND – 0.024 Low across all sites Linked to local industrial sources Elevated levels near port areas 0.5 3.4. Spatial, species, and tissue differences Non-parametric statistical tests indicated significant spatial variation in several metals. The Kruskal–Wallis test showed significant differences in As, V, and Cr concentrations among the four sampling locations (p < 0.001) (Table 10 ). Post hoc analysis (Dunn’s test; not tabulated) identified multiple pairwise differences in these metals among cities. Metal concentrations among fish species also differed significantly for As and V (Kruskal–Wallis, p < 0.05) (Table 10 ). For tissue type, the Mann–Whitney U test indicated that gills contained significantly higher concentrations of Fe, Zn, and Mn than muscle (p < 0.05) (Table 10 ). Table 10 Summary of Statistical Significance (p-values) for Tissue and Site Comparisons Parameter Method Comparison Significant Elements p -value Organ Type Mann-Whitney U Muscle vs. Gills Fe, Zn, Mn < 0.05 Sampling Site Kruskal-Wallis 4 Cities As, V, Cr < 0.001 Fish Species Kruskal-Wallis 3 Species As, V < 0.05 Spearman correlation analysis of metal concentrations in muscle tissue (Table 10 ) revealed a strong positive association between As and V ( r = 0.84, p < 0.001), suggesting a potential common source or uptake pathway. No other significant inter-element correlations were observed. As is known, V can induce cellular oxidative stress by replacing phosphorus in biochemical reactions, while V can inhibit essential enzymes such as Na+/K+-ATPase [ 41 , 42 ]. 4. Discussion The present study provides insights into contamination patterns with potential human health implications. The findings elucidate the interplay among environmental sources of contamination, fish tissue accumulation, and the resulting dietary risks to local populations, particularly vulnerable groups such as children. Geographically, the Red Sea serves as a unique ecological zone impacted by various anthropogenic activities that contribute to heavy metal loading. Jazan emerged as a hotspot for As and V, possibly due to its significant maritime traffic and industrial activities, such as oil refining by [ 12 ]. Previous research indicates that these environmental sources elevate metal levels in the coastal food web, as metals from sediment and water are accumulated by fish and subsequently transferred to human consumers [ 43 – 45 ]. In contrast, Umluj is characterized by relatively limited heavy industry and less intensive coastal infrastructure, and previous Red Sea assessments indicate that less-developed stretches of coastline tend to receive lower anthropogenic metal inputs than major ports and industrial centers, which is consistent with the comparatively low fish-tissue concentrations observed there [ 4 , 9 , 13 , 46 ]. In comparison with previous Red Sea and regional assessments, the arsenic and Cr burdens observed here fall within the upper range of values reported for coastal fishes but are not exceptional when viewed against heavily impacted sites. Table 9 shows that mean As concentrations in muscle (0.079–0.849 mg/kg; maximum 3.29 mg/kg in Jazan and Qunfudah) approach or slightly exceed the FAO/WHO limit of 1 mg/kg, consistent with earlier findings that As is a primary dietary risk driver in Red Sea fish and other regional seafood. Study Zaghloul el. similarly identified As as a leading contributor to non-carcinogenic and carcinogenic risk in Hurghada fish, reporting muscle concentrations that frequently approached or exceeded guideline values, while Shorbagy et al found As to be the dominant carcinogenic element in Nuweiba fish from the Gulf of Aqaba [ 26 , 40 ]. The similarity in As-driven risk across sites suggests a broadly comparable regional exposure pattern, with local maxima (e.g., Jazan, Hurghada, Nuweiba) reflecting areas of intensified coastal development and metal inputs. For chromium, the present study reports mean muscle levels of 0.010–0.904 mg/kg and a maximum of 3.62 mg/kg in Jazan, exceeding the 0.6 mg/kg FAO/WHO standard at the most impacted location (Table 9 ). This agrees with Zaghloul et al., which noted that Cr in several Hurghada species often exceeded seafood safety limits, and with Shorbagy et al., which documented Cr as a consistent component of multi-metal contamination mixtures in Nuweiba fish [ 26 , 40 ]. Overall, the As and Cr levels measured here are broadly comparable to those reported from other Red Sea hotspots, with Jazan falling toward the higher end of the regional spectrum, while less-developed sites like Umluj align more closely with the lower-range concentrations described for less industrialized stretches of the Red Sea coast. The risk assessment calculations indicated that the TR for As in Jazan marginally exceeded the USEPA safe threshold, thereby signifying heightened lifetime cancer risks for individuals consuming locally sourced fish [ 49 ]. This finding aligns with existing literature associating fish consumption, particularly from contaminated waters, with increased cancer risk attributed to accumulated toxins such as As [ 50 ]. The THQ values, while generally below 1.0 for most sites, illustrate the nuanced relationship between bioaccumulation levels in fish and the dietary exposure risks for consumers. Residents who rely on seafood as a dietary staple should be made aware of these findings to make informed nutritional choices, especially given the historical dietary patterns predicated on local consumption of marine resources [ 1 , 16 , 19 , 36 , 51 ]. It is particularly concerning that children are more susceptible to the toxic effects of these elements due to their ongoing physiological development; this further highlights the need for targeted health assessments and educational outreach to at-risk communities. Public health interventions could incorporate monitoring and educational programs focused on the risks associated with heavy metal consumption, tailored to inform local fishing practices and improve community health outcomes [ 52 ] This assessment assumes all As is in its toxic inorganic form, which may overestimate risk, and uses average consumption values, potentially underestimating risk among high-consumption subgroups (e.g., fishing communities). Average non-carcinogenic risk from fish consumption along the Saudi Red Sea coast is low, as all calculated THQ and HI values remained well below the unity threshold, indicating no immediate chronic-toxic concern for the general population under standard intake assumptions. However, the carcinogenic risk profile is strongly shaped by arsenic in Jazan sardines, where the TR for inorganic As reached 1.15×10⁻⁴, the highest value among all cities and species. This probability exceeds the USEPA “negligible risk” benchmark of 1×10⁻⁶ and approaches the upper bound of the commonly cited “acceptable” risk range (10⁻⁶–10⁻⁴), implying that lifetime exposure for frequent consumers of Jazan sardines could edge into a level of concern, especially when combined with co-occurring V and Cr. For high-consumption groups such as artisanal fishermen and coastal households who rely on locally caught sardines several times per week, this elevated TR suggests a non-trivial incremental cancer risk over a lifetime, even though short-term toxicity indicators (THQ, HI) remain below 1.0. These findings therefore do not call for a blanket restriction on fish consumption, but they do justify targeted advisories and closer monitoring in the southern Red Sea, particularly for communities with culturally high fish intake and limited alternative protein sources. It is important to emphasize that the TR estimates are conservative: they assume that all measured arsenic in muscle is present in the more toxic inorganic form and that consumers follow an average per-capita intake of 7 g fish/day, as specified in the risk model. Real-world risk may be lower where organic As dominates or intake is reduced, but it could be higher for subsistence fishers and families whose actual consumption substantially exceeds the assumed average. In summary, this study not only highlights the concerning state of heavy metal contamination in the Saudi Arabian Red Sea fish species but also underscores the complexities surrounding human health, environmental integrity, and dietary practices. It calls for integrative approaches that encompass environmental science, public health nutrition, and community engagement to safeguard food security and public health in vulnerable populations. 5. Conclusion The study demonstrates a clear north–south contamination gradient in Red Sea fish, with Jazan emerging as a hotspot for the As, V, Cr toxic triad and associated marginally elevated carcinogenic risk, while Umluj provides a low-contamination reference site with negligible risk. Fish from Jazan, particularly Sardinella longiceps , exhibited the highest concentrations of the toxic triad (As, V, and Cr). These findings support urgent identification and control of contamination sources in Jazan, alongside the implementation of sustained seafood monitoring programs targeting As, V, and Cr to safeguard public health in the southern Red Sea. Declarations Author Contribution O.M.L.A. was responsible for the conceptualization and design of the study; performed the field collection of 461 fish samples across the four Red Sea coastal cities ; conducted the laboratory tissue preparation and ICP-MS elemental analysis; performed the statistical processing (Mann-Whitney U and Kruskal-Wallis tests); carried out the human health risk assessments (EDI, THQ, HI, and TR) ; and wrote the main manuscript text. The author has read and agreed to the published version of the manuscript. Acknowledgement I would like to thank the laboratory staff for their assistance in ICP-MS analysis and the local fishermen for their support during the sampling campaigns in Umluj, Yanbu, Qunfudah, and Jazan. The author thanks Taibah University for the funds, grants, and support received during the preparation of this manuscript. 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Mar Pollut Bull 198:115864. https://doi.org/10.1016/J.MARPOLBUL.2023.115864 Chan WS, Routh J, Luo C et al (2021) Metal accumulations in aquatic organisms and health risks in an acid mine-affected site in South China. Environ Geochem Health 43. https://doi.org/10.1007/s10653-021-00923-0 Vona R, Gambardella L, Cittadini C et al (2019) Biomarkers of oxidative stress in metabolic syndrome and associated diseases. Oxid Med Cell Longev 2019 Wintergerst ES, Maggini S, Hornig DH (2007) Contribution of selected vitamins and trace elements to immune function. Ann Nutr Metab 51 Dubey P, Thakur V, Chattopadhyay M (2020) Role of minerals and trace elements in diabetes and insulin resistance. Nutrients 12 Koletzko B, Godfrey KM, Poston L et al (2019) Nutrition during pregnancy, lactation and early childhood and its implications for maternal and long-term child health: The early nutrition project recommendations. Ann Nutr Metab 74 Bhattacharya PT, Misra SR, Hussain M (2016) Nutritional Aspects of Essential Trace Elements in Oral Health and Disease: An Extensive Review. Scientifica (Cairo) 2016 Pereira TCB, Campos MM, Bogo MR (2016) Copper toxicology, oxidative stress and inflammation using zebrafish as experimental model. J Appl Toxicol 36. https://doi.org/10.1002/jat.3303 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8554945","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":572565917,"identity":"3981c196-3df9-4a75-9681-6d8de18a71ad","order_by":0,"name":"Omar M. L. 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Introduction","content":"\u003cp\u003eHeavy metal contamination in marine ecosystems is a persistent global concern because these elements are toxic, non-biodegradable, and prone to bioaccumulation and biomagnification along aquatic food webs. [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Coastal zones, which host dense human populations and intensive industrial, agricultural, touristic, and maritime activities, are particularly vulnerable to heavy metal inputs from domestic effluents, petrochemical industries, desalination plants, shipping, and urban runoff. [\u003cspan additionalcitationids=\"CR3 CR4 CR5\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Once released, metals such as Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr), Iron (Fe), Nickel (Ni), Copper (Cu), Vanadium (V), Manganese (Mn), and Zinc (Zn) can partition into seawater and sediments, acting as long-term sources for uptake by benthic and pelagic organisms [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Numerous studies have shown that marine fish and shellfish accumulate these metals in their tissues, sometimes at levels posing non-carcinogenic and carcinogenic risks to consumers, especially children and high-intake groups [\u003cspan additionalcitationids=\"CR10 CR11 CR12\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSeafood is widely promoted as a nutrient-dense food, rich in high-quality protein and omega-3 fatty acids, and is a significant component of diets in many coastal countries [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] This nutritional benefit can be offset when seafood is contaminated by toxic metals such as As, Cd, Hg, and Pb, which have been associated with neurotoxicity, nephrotoxicity, developmental impairment, and increased cancer risk [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR18 CR19\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Recent regional and global assessments indicate that arsenic and mercury are often the dominant contributors to health risk from seafood consumption, with Cd and Pb also of concern in specific locations and species. [\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These findings have driven international efforts by the WHO, FAO, EFSA, and national agencies to establish maximum permissible levels for key metals in seafood and to emphasize continuous monitoring and risk assessment. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Red Sea is a semi-enclosed, oligotrophic basin of exceptional biodiversity and economic importance, supporting fisheries, tourism, shipping, and intensive coastal development, particularly along the Saudi coastline [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Rapid urbanization, expansion of petroleum and petrochemical industries, cement production, ports, and desalination facilities have markedly increased anthropogenic metal inputs to this region [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Studies on Red Sea sediments, seawater, mangroves, and biota have documented elevated and spatially heterogeneous levels of Cd, Pb, Zn, Cu, Ni, and other metals, with the highest burdens typically near industrialized and urbanized hubs such as Jeddah, Rabigh, Hurghada, and Yanbu [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR5 CR6 CR7\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Ecological and human-health risk assessments based on sediments and water generally indicate localized considerable to very high environmental risk, particularly for Cd and Pb, and highlight the need for continuous monitoring and source control [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite this growing body of work, there are still comparatively few integrated assessments of multi-element contamination directly in commercially important Red Sea seafood, especially along the western Saudi coast. Most existing studies focus on sediments, mangroves, or limited suites of metals in selected fish species, and data for combined fish\u0026ndash;crab matrices across multiple coastal cities remain sparse [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Given the heavy reliance of coastal communities on local fisheries in cities such as Yanbu, Al Qunfudhah, and Jazan, there is a clear need to quantify the burden of a broad range of potentially toxic elements in edible marine species and to compare these burdens among sites that differ in the intensity of industrial and urban development.\u003c/p\u003e \u003cp\u003eThe present study addresses three key gaps:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eDetermine the concentrations of various metals, including Cr(III), Hg(II), Pb(II), Mn(II), As(III), Cd(II), Ni(II), V(III), Cu(II), Fe(II), and Zn(II), in the gills and muscles of three fish species: \u003cem\u003eSardinella longiceps, Carangoides spp., and Herklotsichthys spp\u003c/em\u003e.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eComparing tissue-specific and site-specific accumulation patterns against international guideline values, this study provides new evidence regarding the status of metal contamination in Red Sea seafood.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eContribute to the regional database necessary for risk assessment and the sustainable management of coastal resources.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Study Area and Sample Collection\u003c/h2\u003e \u003cp\u003eFish samples, including various fish species (\u003cem\u003eSardinella longiceps, Carangoides spp., Herklotsichthys spp\u003c/em\u003e.), were collected from four well-characterized locations in the western Red Sea of Saudi Arabia, specifically Umluj, Yanbu, Qunfudhah, and Jazan. The fish samples were purchased from local fishermen immediately after landing at all sites. Species were identified morphologically using standard taxonomic keys based on external characters (body shape, coloration, fin morphology, and meristic counts). Questionable specimens were verified by an ichthyology expert. These species are the staple fish for the Saudi Arabian population along the Red Sea coast. Fish samples were collected between September 2023 and January 2024 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Following collection, samples were transported to the laboratory in insulated ice chests and stored at -40\u0026deg;C until dissection and analysis. The geographical coordinates and sampling locations are illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \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\u003eSummary of Diet, Habitat, and Sample Sizes for Studied Fish Species\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrimary Diet\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHabitat Preference\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo of samples\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndian Oil Sardine (\u003cem\u003eSardinella longiceps\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePhytoplankton \u0026amp; Zooplankton\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCoastal-pelagic; prefers upwelling zones.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e180\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTrevallies / Jacks (\u003cem\u003eCarangoides spp.\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSmall fish, Crustaceans, Squid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eReef-associated; bays and rocky outcrops.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e140\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBluestripe Herring (\u003cem\u003eHerklotsichthys quad.\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eZooplankton (nocturnal)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eShallow lagoons and mangroves.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e141\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=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBiometric data of Sampling Site Locations, Collection Periods, and Sample Sizes.\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\u003eCity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCoordinates\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCollection Date\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAvg. Length (cm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAvg. Weight (g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eNo of samples\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25.20\u0026deg; N, 37.2\u0026deg; E\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOct 2023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15\u0026ndash;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u0026ndash;90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e35\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e300\u0026ndash;600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eHerklotsichthys quad.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u0026ndash;13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026ndash;45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.07\u0026deg; N, 38.05\u0026deg; E\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSept 2023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15\u0026ndash;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u0026ndash;90\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e300\u0026ndash;600\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eHerklotsichthys quad.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u0026ndash;13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026ndash;45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19.03\u0026deg; N, 41.16\u0026deg; E\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJan 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15\u0026ndash;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u0026ndash;90\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e300\u0026ndash;600\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eHerklotsichthys quad.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u0026ndash;13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026ndash;45\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 \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17.04\u0026deg; N, 42.46\u0026deg; E\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJan 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15\u0026ndash;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u0026ndash;90\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e300\u0026ndash;600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e35\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\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eHerklotsichthys quad.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u0026ndash;13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u0026ndash;45\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\u003eTotal of samples\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e \u003cp\u003e461\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Sample Preparation and Acid Digestion\u003c/h2\u003e \u003cp\u003eTarget tissues (muscle and gills) were dissected with stainless steel instruments, rinsed with deionized water, and homogenized. Approximately 0.50 g (dry weight) of each tissue sample was weighed into a 250 mL acid‑washed glass beaker. A digestion mixture of 12 mL concentrated HNO₃ (69%) and 6 mL H₂O₂ (30%) was added to each sample. The beakers were covered with watch glasses and heated on a hot plate at 140\u0026deg;C for 1.5\u0026ndash;2 hours, until all organic matter was completely oxidized and the digest became clear, following a previously validated protocol by Alharbi et al. (2018) [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The digests were then cooled to room temperature prior to filtration and dilution.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Filtration and Elemental Analysis\u003c/h2\u003e \u003cp\u003eOnce cooled, the digestates were filtered through Whatman No. 42 filter paper into volumetric tubes to remove any remaining siliceous material. The solutions were then diluted to a final volume of 50 mL using ultra-pure distilled water. Trace element concentrations were determined using an Agilent 7500 Series ICP MS (Agilent Technologies, USA). The instrument was operated at an RF power of 1550 W, with plasma gas (Ar) flow of 15.0 L min⁻\u0026sup1;, auxiliary gas flow of 1.0 L min⁻\u0026sup1;, and nebulizer gas flow of 0.90 L min⁻\u0026sup1;. The sampling depth was set to 8 mm below the load coil. Helium collision cell mode (He mode) was used to minimize polyatomic interferences for all monitored isotopes. The following isotopes were measured: ⁵\u0026sup1;V, ⁵\u0026sup2;Cr, ⁵⁵Mn, ⁵⁷Fe, ⁶⁰Ni, ⁶\u0026sup3;Cu, ⁶⁶Zn, ⁷⁵As, \u0026sup1;\u0026sup1;\u0026sup1;Cd, \u0026sup2;⁰⁸Pb, and \u0026sup2;⁰\u0026sup2;Hg. To correct for matrix effects and instrumental drift, ⁷\u0026sup2;Ge, \u0026sup1;\u0026sup1;⁵In, and \u0026sup2;⁰⁹Bi were added online as internal standards at a concentration of 10 \u0026micro;g L⁻\u0026sup1;. The instrument was calibrated using a series of multi-element external standards prepared in the same acid matrix as the samples, covering the expected concentration range for all analytes. Calibration curves were linear (R\u0026sup2; \u0026gt; 0.999) for all monitored elements. Instrumental parameters were tuned daily with a multi-element solution to maximize sensitivity and ensure low oxide and doubly charged ion ratios[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Quality Control and Statistical Analysis\u003c/h2\u003e \u003cp\u003eThe accuracy of the ICP MS measurements was evaluated using the certified reference material DORM 4 Fish Protein (National Research Council Canada), processed and analyzed under the same digestion and instrumental conditions as the samples. Recoveries for all target elements were within acceptable limits, ranging from 92% for As to 105% for Zn, confirming the accuracy of the method. The limits of detection (LOD) and limits of quantification (LOQ) were calculated as three times (3σ) and ten times (10σ), respectively, the standard deviation of the reagent blank signals analyzed throughout the batch sequence[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eStatistical processing was performed using SPSS (Version 26.0) and GraphPad Prism. Before the comparative analysis, the dataset's distribution was evaluated using the Shapiro-Wilk normality test. Because most trace element concentrations deviated from normality (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), nonparametric statistical methods were employed. The following tests were used to interpret the data: Mann-Whitney U Test: used to compare metal concentrations between the two distinct tissue types (Gills vs. Muscle) (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). Kruskal-Wallis H Test: Applied to identify significant differences in bioaccumulation across the four sampling locations (Umluj, Yanbu, Qunfudah, and Jazan) and among the three fish species.Dunn\u0026rsquo;s Post-hoc Test: Conducted following significant Kruskal-Wallis results to pinpoint specific pairs of locations or species that differed significantly.Spearman Correlation Matrix: Utilized to investigate the relationships between different metals and to identify potential familiar sources of contamination. Statistical significance for all tests was determined at a 95% confidence level (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). All data are presented as Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;Standard Deviation (SD).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Health Risk Assessment\u003c/h2\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.5.1. Target Hazard Quotient (THQ)\u003c/h2\u003e \u003cp\u003eThe potential non-carcinogenic health risk associated with heavy metal exposure from fish consumption was evaluated using the Target Hazard Quotient (THQ). The THQ is a unitless index developed by the United States Environmental Protection Agency [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]To estimate the risk level of pollutant exposure. A THQ value less than 1 (unity) indicates that the exposure level is below the reference dose and that there is no significant chronic-toxic risk to consumers. Conversely, a THQ\u0026thinsp;\u0026ge;\u0026thinsp;1 indicates a potential health concern [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe THQ was calculated using the following equation:\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:THQ=\\frac{EF\\times\\:ED\\times\\:FIR\\times\\:CF\\times\\:CM}{WAB\\times\\:ATn\\times\\:RfD}\\times\\:\\)\u003c/span\u003e \u003c/span\u003e10\u003csup\u003e\u0026minus;3\u003c/sup\u003e\u003c/p\u003e \u003cp\u003ewhere THQ is the target hazard quotient (unitless); EF is the exposure frequency (365 days/year); ED is the exposure duration (70 years, representing lifetime exposure for non-cancer risk); FIR is the fish ingestion rate (7 g/person/day, as recommended by Ministry of Environment, Water and Agriculture (MEWA, 2023); CF is the conversion factor (0.2) used to convert fresh weight to dry weight, assuming 80% moisture content in fish muscle [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. CM is the concentration of the metal in fish muscle (mg/kg dry weight); WAB is the average adult body weight (60 kg) [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]; ATₙ is the averaging time for non-carcinogenic effects, calculated as EF \u0026times; ED\u0026thinsp;=\u0026thinsp;25,550 days; RfD is the oral reference dose of the metal (mg/kg/day), representing the maximum daily exposure unlikely to cause adverse non-cancer health effects [\u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe RfD values adopted for each metal followed the USEPA guidelines (2024)[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.5.2. Hazard Index (HI)\u003c/h2\u003e \u003cp\u003eIn real-world exposure scenarios, consumers are often exposed to multiple trace elements simultaneously. To account for the potential additive effects of these contaminants, the Hazard Index (HI) was employed as a comprehensive measure of the total non-carcinogenic risk (USEPA, 2006). The HI is defined as the arithmetic sum of the individual Target Hazard Quotients (THQs) calculated for each metal in the study.\u003c/p\u003e \u003cp\u003eThe Hazard Index was calculated using the following equation:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$\\:HI=\\:\\sum\\:_{i=1}^{n}THQi$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere: HI is the Hazard Index for a specific fish species. THQi represents the Target Hazard Quotient for the IH trace element in the mixture. n is the total number of trace elements evaluated (in this study: V, Cr, Mn, Co, Ni, Zn, As, Fe, Pb, Cu, and Cd).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.5.3. Target Cancer Risk (TR)\u003c/h2\u003e \u003cp\u003eFor elements classified as potential carcinogens, the Target Cancer Risk (TR) is estimated to represent the incremental probability that an individual will develop cancer over a lifetime due to exposure (USEPA, 1989). While several trace metals were analyzed in this study, Arsenic (As) is specifically identified by the USEPA as a known carcinogen, necessitating a dedicated assessment of its carcinogenic potential (USEPA, 2024) [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe TR for inorganic Arsenic was calculated by multiplying the exposure level by the oral carcinogenic potency slope (\u003cem\u003eCPSo\u003c/em\u003e), using the following model:\u003c/p\u003e \u003cp\u003e \u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:TR=\\frac{EF\\times\\:ED\\times\\:FIR\\times\\:CM\\times\\:CPSo}{WAB\\times\\:ATn}\\times\\:\\)\u003c/span\u003e \u003c/span\u003e10\u003csup\u003e\u0026minus;3\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWhere: TR: Target Cancer Risk (unitless probability). CPSo: Carcinogenic Potency Slope, oral (1.5 mg/kg/day)\u003csup\u003e\u0026minus;1\u003c/sup\u003e for As [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.5.4. Estimated Daily Intake (EDI)\u003c/h2\u003e \u003cp\u003eThe Estimated Daily Intake (EDI) of heavy metals through fish consumption depends on the concentration of the elements in the fish muscle tissue and the quantity of fish consumed daily[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. This metric is essential for comparing the actual intake of metals against the Provisional Tolerable Daily Intake (PTDI) set by international health organizations.\u003c/p\u003e \u003cp\u003eThe EDI was calculated using the following formula:\u003cdiv id=\"Equb\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equb\" name=\"EquationSource\"\u003e\n$$\\:EDI=\\frac{CM\\times\\:DCfish}{WB}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere: EDI: Estimated Daily Intake of a specific metal (mg/kg body weight/day). DC fish: Daily consumption of fish per capita (7 g/day, as per MEWA, 2023). BW: Average body weight of an adult (60 kg, as per MEWA, 2023).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003e \u003cb\u003e3.1 Identification of Primary Hazard Elements\u003c/b\u003e \u003c/p\u003e \u003cp\u003e3.2 Across all four sampling locations and three fish species, As was detected in both gill and muscle tissues at higher risk-based levels than other analyzed metals (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In gill tissue, the highest mean As concentration was observed in Qunfudah (0.873\u0026thinsp;\u0026plusmn;\u0026thinsp;1.41 mg/kg), remaining below the FAO/WHO limit of 1.0 mg/kg, with a range of 0.03\u0026ndash;2.51 mg/kg (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Cd, Cr, Mn, Ni, Cu, zinc Zn, Fe, and V in gills were all below their respective FAO/WHO or national limits where such values exist, although Cr approached the upper guideline range in Qunfudah (0.642\u0026thinsp;\u0026plusmn;\u0026thinsp;1.11 mg/kg; range 0.05\u0026ndash;1.92 mg/kg; guideline 0.15\u0026ndash;1.0 mg/kg) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\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\u003eHighest Mean Concentrations of Heavy Metals in Fish Gills vs. WHO Limits by Location (mg/kg)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeavy Metal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocation (Highest Mean)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHighest Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD (mg/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRange [Min \u0026ndash; Max] (mg/kg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWHO/FAO Limit (mg/kg)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.873\u0026thinsp;\u0026plusmn;\u0026thinsp;1.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.03\u0026ndash;2.51]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.033\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.003\u0026ndash;0.08]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.642\u0026thinsp;\u0026plusmn;\u0026thinsp;1.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.05\u0026ndash;1.92]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.15\u0026ndash;1.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.00\u0026thinsp;\u0026plusmn;\u0026thinsp;19.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.06\u0026ndash;39.6]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.548\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.56\u0026ndash;5.60]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30\u0026ndash;40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.754\u0026thinsp;\u0026plusmn;\u0026thinsp;1.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 2.26]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.463\u0026thinsp;\u0026plusmn;\u0026thinsp;0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.08\u0026ndash;1.21]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.031\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.01\u0026ndash;0.04]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u0026ndash;0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.643\u0026thinsp;\u0026plusmn;\u0026thinsp;2.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 4.84]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eN/S\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=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eHighest Heavy Metal Concentrations in Fish Muscles vs. FAO/WHO Limits (mg/kg).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeavy Metal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[Min \u0026ndash; Max]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFAO/WHO Limit\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.161\u0026thinsp;\u0026plusmn;\u0026thinsp;1.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.06\u0026ndash;3.29]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.017\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.008\u0026ndash;0.03]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.207\u0026thinsp;\u0026plusmn;\u0026thinsp;2.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 3.61]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.005\u0026thinsp;\u0026plusmn;\u0026thinsp;4.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.11\u0026ndash;8.48]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.125\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.08\u0026ndash;0.18]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.038\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 0.11]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUmluj \u0026amp; Yanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.014\u0026thinsp;\u0026plusmn;\u0026thinsp;0.00 / 0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[0.007\u0026ndash;0.02]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.019\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 0.03]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.145\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[ND \u0026ndash; 6.43]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eN/A\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\u003eIn muscle tissue, the highest mean As concentration was recorded in Jazan (1.161\u0026thinsp;\u0026plusmn;\u0026thinsp;1.85 mg/kg; range 0.06\u0026ndash;3.29 mg/kg), with the mean exceeding the FAO/WHO limit of 1.0 mg/kg (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Cr in Jazan muscles also exceeded its guideline value (mean 1.207\u0026thinsp;\u0026plusmn;\u0026thinsp;2.08 mg/kg; range ND\u0026ndash;3.61 mg/kg; guideline 0.6 mg/kg) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). For all sites, mean concentrations of Cd, Fe, Zn, Cu, Mn, Ni, and V in muscle remained below their respective guideline values where available (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e); no guideline value is specified for V in fish muscle (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe maximum recorded muscle concentration of V occurred in Jazan sardines (6.435 mg/kg, within a site mean of 2.145\u0026thinsp;\u0026plusmn;\u0026thinsp;3.71 mg/kg; range ND\u0026ndash;6.43 mg/kg) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Essential elements (Fe, Zn, Cu) showed higher absolute concentrations than non-essential toxic metals but remained within their accepted limits in both gill and muscle tissues (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Regional Risk Profile\u003c/h2\u003e \u003cp\u003eTHQs for As, Cd, Cr, and V, and the corresponding TTHQ, are presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. For all cities and species, individual THQ values for each metal were below 1.0. TTHQ values ranged from 0.00049 (Umluj, Sardinella longiceps) to 0.30628 (Jazan, Sardinella longiceps). The cumulative non-carcinogenic risk, expressed as the Hazard Index (HI), was identical to the TTHQ for each city\u0026ndash;species combination because HI was calculated as the sum of THQs for these metals. HI values across cities and species are shown in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, ranging from 0.00049 to 0.30628, with the highest HI observed for Sardinella longiceps in Jazan and the lowest HI observed for the same species in Umluj.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e: Target Hazard Quotients (THQ) and Total THQ (TTHQ) for Studied Fish Species\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\u003eCity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCd\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCr\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eTTHQ\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00042\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00004\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00049\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\u003e\u003cem\u003eHerklotsichthys spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00112\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00117\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\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.03034\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.03048\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00236\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00006\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00243\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\u003e\u003cem\u003eHerklotsichthys spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00148\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00026\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00175\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\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00338\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00340\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00527\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00563\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\u003e\u003cem\u003eHerklotsichthys spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01692\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00031\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.01774\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\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.07390\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00075\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.07468\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eSardinella longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.25597\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00039\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.02812\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.02145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.30628\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\u003e\u003cem\u003eHerklotsichthys spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00511\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00514\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\u003e\u003cem\u003eCarangoides spp.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00978\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.00987\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=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummarizes the cumulative risk (HI) for each species across the four sampling sites, based on the additive THQ values:\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSardinella longiceps\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHerklotsichthys spp.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCarangoides spp.\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00117\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.03048\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00243\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00175\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00340\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00563\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.01774\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.07468\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.30628\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00514\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.00987\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\u003eTR values for As are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. TR values varied by city and species from 1.89 \u0026times; 10⁻⁷ (Umluj, Sardinella longiceps) to 1.15 \u0026times; 10⁻⁴ (Jazan, Sardinella longiceps) (Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e). For the remaining city\u0026ndash;species combinations, TR values fell between these two extremes, with all values within the 10⁻⁷\u0026ndash;10⁻⁴ range (Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe TR values for the four regions are summarized below:\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSardinella longiceps\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHerklotsichthys spp.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCarangoides spp.\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.89 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.06 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.36 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.06 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.65 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.52 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.37 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.61 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.32 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.15 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.29 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.40 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\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\u003eEDI values for As, Cd, Cr, and V via consumption of Sardinella longiceps are shown in Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. EDI for As ranged from 6.31 \u0026times; 10⁻⁷ mg/kg bw/day in Umluj to 3.84 \u0026times; 10⁻⁴ mg/kg bw/day in Jazan (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e). EDI values for Cd, Cr, and V were lower than those for As at all sites, with Cd ranging from 2.08 \u0026times; 10⁻⁷ to 1.96 \u0026times; 10⁻⁶ mg/kg bw/day, Cr from 0 to 4.22 \u0026times; 10⁻⁴ mg/kg bw/day, and V from 0 to 7.51 \u0026times; 10⁻⁴ mg/kg bw/day (Table\u0026nbsp;\u003cspan refid=\"Tab8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe calculated EDI values for all metals across Umluj, Yanbu, Qunfudah, and Jazan.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCd\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCr\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eV\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUmluj\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.31 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.08 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYanbu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.55 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.73 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQunfudah\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.90 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.44 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.44 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eS. longiceps\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.84 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.96 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.22 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7.51 \u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\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\u003eTable\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e summarizes the mean concentration ranges of metals in this study, the locations of highest concentrations, corresponding FAO/WHO standards, and qualitative statements from previous studies for comparison. Mean As concentrations in muscle ranged from 0.079 to 0.849 mg/kg, with maximum values up to 3.29 mg/kg in Jazan and Qunfudah; Cr ranged from 0.010 to 0.904 mg/kg (maximum 3.62 mg/kg in Jazan); and Mn exceeded the listed 0.01 mg/kg limit at all locations (0.003\u0026ndash;0.500 mg/kg) (Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). Fe, Zn, Cd, Cu, and Ni remained within their respective FAO/WHO standards, where available (Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Heavy Metal Concentrations and Safety Limits (mg/kg) (w/w)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeavy Metal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThis Study (Mean Range)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLocations of High Concentration\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eFAO/WHO Standard\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.079\u0026ndash;0.849\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJazan \u0026amp; Qunfudah (Max: 3.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eReported as a primary health risk factor\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDominant contributor to carcinogenic risk\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.010\u0026ndash;0.904\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003cp\u003e(Max: 3.62)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOften exceeds limits in coastal species\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePresent in multi-metal mixtures\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.003\u0026ndash;0.500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eYanbu \u0026amp; Qunfudah (Exceeds limit in all)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLinked to industrial runoff in ports\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFound at elevated levels in sediments\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.080\u0026ndash;10.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJazan\u003c/p\u003e \u003cp\u003e(Max: 39.6 in Gills)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHighly accumulated in internal organs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThe most accumulated element in Nuweiba\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.029\u0026ndash;1.924\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQunfudah (Max: 5.60 in Gills)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHigh levels found in reef-associated fish\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eDominant metal in fish muscle profiles\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.005\u0026ndash;0.024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow across all sites\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLow burdens are generally reported\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWithin regulatory limits for the region\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCu\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0004\u0026ndash;0.585\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eYanbu (Max: 2.26 in Gills)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGenerally, within safety limits\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWithin safety limits for human consumption\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eND \u0026ndash; 0.024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow across all sites\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLinked to local industrial sources\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElevated levels near port areas\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Spatial, species, and tissue differences\u003c/h2\u003e \u003cp\u003eNon-parametric statistical tests indicated significant spatial variation in several metals. The Kruskal\u0026ndash;Wallis test showed significant differences in As, V, and Cr concentrations among the four sampling locations (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). Post hoc analysis (Dunn\u0026rsquo;s test; not tabulated) identified multiple pairwise differences in these metals among cities. Metal concentrations among fish species also differed significantly for As and V (Kruskal\u0026ndash;Wallis, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e). For tissue type, the Mann\u0026ndash;Whitney U test indicated that gills contained significantly higher concentrations of Fe, Zn, and Mn than muscle (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of Statistical Significance (p-values) for Tissue and Site Comparisons\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMethod\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eComparison\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSignificant Elements\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOrgan Type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMann-Whitney U\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMuscle vs. Gills\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFe, Zn, Mn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSampling Site\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKruskal-Wallis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 Cities\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAs, V, Cr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFish Species\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKruskal-Wallis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3 Species\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAs, V\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.05\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\u003eSpearman correlation analysis of metal concentrations in muscle tissue (Table\u0026nbsp;\u003cspan refid=\"Tab10\" class=\"InternalRef\"\u003e10\u003c/span\u003e) revealed a strong positive association between As and V (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.84, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting a potential common source or uptake pathway. No other significant inter-element correlations were observed. As is known, V can induce cellular oxidative stress by replacing phosphorus in biochemical reactions, while V can inhibit essential enzymes such as Na+/K+-ATPase [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe present study provides insights into contamination patterns with potential human health implications. The findings elucidate the interplay among environmental sources of contamination, fish tissue accumulation, and the resulting dietary risks to local populations, particularly vulnerable groups such as children. Geographically, the Red Sea serves as a unique ecological zone impacted by various anthropogenic activities that contribute to heavy metal loading. Jazan emerged as a hotspot for As and V, possibly due to its significant maritime traffic and industrial activities, such as oil refining by [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Previous research indicates that these environmental sources elevate metal levels in the coastal food web, as metals from sediment and water are accumulated by fish and subsequently transferred to human consumers [\u003cspan additionalcitationids=\"CR44\" citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. In contrast, Umluj is characterized by relatively limited heavy industry and less intensive coastal infrastructure, and previous Red Sea assessments indicate that less-developed stretches of coastline tend to receive lower anthropogenic metal inputs than major ports and industrial centers, which is consistent with the comparatively low fish-tissue concentrations observed there [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn comparison with previous Red Sea and regional assessments, the arsenic and Cr burdens observed here fall within the upper range of values reported for coastal fishes but are not exceptional when viewed against heavily impacted sites. Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows that mean As concentrations in muscle (0.079\u0026ndash;0.849 mg/kg; maximum 3.29 mg/kg in Jazan and Qunfudah) approach or slightly exceed the FAO/WHO limit of 1 mg/kg, consistent with earlier findings that As is a primary dietary risk driver in Red Sea fish and other regional seafood. Study Zaghloul el. similarly identified As as a leading contributor to non-carcinogenic and carcinogenic risk in Hurghada fish, reporting muscle concentrations that frequently approached or exceeded guideline values, while Shorbagy et al found As to be the dominant carcinogenic element in Nuweiba fish from the Gulf of Aqaba [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. The similarity in As-driven risk across sites suggests a broadly comparable regional exposure pattern, with local maxima (e.g., Jazan, Hurghada, Nuweiba) reflecting areas of intensified coastal development and metal inputs.\u003c/p\u003e \u003cp\u003eFor chromium, the present study reports mean muscle levels of 0.010\u0026ndash;0.904 mg/kg and a maximum of 3.62 mg/kg in Jazan, exceeding the 0.6 mg/kg FAO/WHO standard at the most impacted location (Table\u0026nbsp;\u003cspan refid=\"Tab9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). This agrees with Zaghloul et al., which noted that Cr in several Hurghada species often exceeded seafood safety limits, and with Shorbagy et al., which documented Cr as a consistent component of multi-metal contamination mixtures in Nuweiba fish [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Overall, the As and Cr levels measured here are broadly comparable to those reported from other Red Sea hotspots, with Jazan falling toward the higher end of the regional spectrum, while less-developed sites like Umluj align more closely with the lower-range concentrations described for less industrialized stretches of the Red Sea coast.\u003c/p\u003e \u003cp\u003eThe risk assessment calculations indicated that the TR for As in Jazan marginally exceeded the USEPA safe threshold, thereby signifying heightened lifetime cancer risks for individuals consuming locally sourced fish [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. This finding aligns with existing literature associating fish consumption, particularly from contaminated waters, with increased cancer risk attributed to accumulated toxins such as As [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. The THQ values, while generally below 1.0 for most sites, illustrate the nuanced relationship between bioaccumulation levels in fish and the dietary exposure risks for consumers. Residents who rely on seafood as a dietary staple should be made aware of these findings to make informed nutritional choices, especially given the historical dietary patterns predicated on local consumption of marine resources [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]. It is particularly concerning that children are more susceptible to the toxic effects of these elements due to their ongoing physiological development; this further highlights the need for targeted health assessments and educational outreach to at-risk communities. Public health interventions could incorporate monitoring and educational programs focused on the risks associated with heavy metal consumption, tailored to inform local fishing practices and improve community health outcomes [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e] This assessment assumes all As is in its toxic inorganic form, which may overestimate risk, and uses average consumption values, potentially underestimating risk among high-consumption subgroups (e.g., fishing communities).\u003c/p\u003e \u003cp\u003eAverage non-carcinogenic risk from fish consumption along the Saudi Red Sea coast is low, as all calculated THQ and HI values remained well below the unity threshold, indicating no immediate chronic-toxic concern for the general population under standard intake assumptions. However, the carcinogenic risk profile is strongly shaped by arsenic in Jazan sardines, where the TR for inorganic As reached 1.15\u0026times;10⁻⁴, the highest value among all cities and species. This probability exceeds the USEPA \u0026ldquo;negligible risk\u0026rdquo; benchmark of 1\u0026times;10⁻⁶ and approaches the upper bound of the commonly cited \u0026ldquo;acceptable\u0026rdquo; risk range (10⁻⁶\u0026ndash;10⁻⁴), implying that lifetime exposure for frequent consumers of Jazan sardines could edge into a level of concern, especially when combined with co-occurring V and Cr. For high-consumption groups such as artisanal fishermen and coastal households who rely on locally caught sardines several times per week, this elevated TR suggests a non-trivial incremental cancer risk over a lifetime, even though short-term toxicity indicators (THQ, HI) remain below 1.0. These findings therefore do not call for a blanket restriction on fish consumption, but they do justify targeted advisories and closer monitoring in the southern Red Sea, particularly for communities with culturally high fish intake and limited alternative protein sources. It is important to emphasize that the TR estimates are conservative: they assume that all measured arsenic in muscle is present in the more toxic inorganic form and that consumers follow an average per-capita intake of 7 g fish/day, as specified in the risk model. Real-world risk may be lower where organic As dominates or intake is reduced, but it could be higher for subsistence fishers and families whose actual consumption substantially exceeds the assumed average.\u003c/p\u003e \u003cp\u003eIn summary, this study not only highlights the concerning state of heavy metal contamination in the Saudi Arabian Red Sea fish species but also underscores the complexities surrounding human health, environmental integrity, and dietary practices. It calls for integrative approaches that encompass environmental science, public health nutrition, and community engagement to safeguard food security and public health in vulnerable populations.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThe study demonstrates a clear north\u0026ndash;south contamination gradient in Red Sea fish, with Jazan emerging as a hotspot for the As, V, Cr toxic triad and associated marginally elevated carcinogenic risk, while Umluj provides a low-contamination reference site with negligible risk. Fish from Jazan, particularly \u003cem\u003eSardinella longiceps\u003c/em\u003e, exhibited the highest concentrations of the toxic triad (As, V, and Cr). These findings support urgent identification and control of contamination sources in Jazan, alongside the implementation of sustained seafood monitoring programs targeting As, V, and Cr to safeguard public health in the southern Red Sea.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eO.M.L.A. was responsible for the conceptualization and design of the study; performed the field collection of 461 fish samples across the four Red Sea coastal cities ; conducted the laboratory tissue preparation and ICP-MS elemental analysis; performed the statistical processing (Mann-Whitney U and Kruskal-Wallis tests); carried out the human health risk assessments (EDI, THQ, HI, and TR) ; and wrote the main manuscript text. The author has read and agreed to the published version of the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eI would like to thank the laboratory staff for their assistance in ICP-MS analysis and the local fishermen for their support during the sampling campaigns in Umluj, Yanbu, Qunfudah, and Jazan. The author thanks Taibah University for the funds, grants, and support received during the preparation of this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlharbi OML, Khattab RA, Ali I et al (2019) Assessment of heavy metals contamination in the sediments and mangroves (Avicennia marina) at Yanbu coast, Red Sea, Saudi Arabia. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.marpolbul.2019.110669\u003c/span\u003e\u003cspan address=\"10.1016/j.marpolbul.2019.110669\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Mar Pollut Bull 149:\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCai C, Devassy RP, El-Sherbiny MM, Agusti S (2022) Cement and oil refining industries as the predominant sources of trace metal pollution in the Red Sea: A systematic study of element concentrations in the Red Sea zooplankton. 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Scientifica (Cairo) 2016\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePereira TCB, Campos MM, Bogo MR (2016) Copper toxicology, oxidative stress and inflammation using zebrafish as experimental model. J Appl Toxicol 36. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/jat.3303\u003c/span\u003e\u003cspan address=\"10.1002/jat.3303\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Heavy metals, Bioaccumulation, Fish species, Health risk assessment, Red Sea, Environmental monitoring","lastPublishedDoi":"10.21203/rs.3.rs-8554945/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8554945/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigated the bioaccumulation of trace elements Arsenic (As), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr), Iron (Fe), Nickel (Ni), Copper (Cu), Vanadium (V), Manganese (Mn), and Zinc (Zn) in three commercially significant fish species (\u003cem\u003eSardinella longiceps\u003c/em\u003e, \u003cem\u003eHerklotsichthys spp.\u003c/em\u003e, and \u003cem\u003eCarangoides spp.\u003c/em\u003e). A total of 461 fish samples were collected from four major coastal cities along the Saudi Arabian Red Sea: Umluj, Yanbu, Qunfudah, and Jazan. Metal concentrations were analyzed in both gill and muscle tissues using ICP-MS. Results indicated that essential elements (Fe, Zn, Cu) were generally within safety limits; however, a significant geographic gradient was observed. Jazan emerged as a critical hotspot, with As and Cr levels exceeding FAO/WHO maximum permissible limits in muscle tissue. Statistical analysis (Mann-Whitney U) confirmed that gills sequestered significantly higher concentrations of Mn, Zn, and Fe (\u003cem\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.05\u003c/em\u003e) than edible muscles. Human health risk assessments, including Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), and Hazard Index (HI), remained below threshold levels (\u003cem\u003e\u0026lt;\u0026thinsp;1.0\u003c/em\u003e), suggesting no immediate non-carcinogenic threat. However, the Target Cancer Risk (TR) for Arsenic in Jazan (1.15\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e) slightly exceeded the USEPA negligible risk threshold. These findings identify a distinct north-south pollution gradient, with Jazan representing a priority area for monitoring due to elevated As and Cr levels and a non-negligible carcinogenic risk from arsenic. The low contamination in Umluj provides a valuable regional baseline.\u003c/p\u003e","manuscriptTitle":"Bioaccumulation and Health Risk Assessment of Heavy Metals in Commercial Fish from the Red Sea, Saudi Arabia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-13 08:28:47","doi":"10.21203/rs.3.rs-8554945/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"58688a41-6c25-47b2-ab43-6962612bdbf1","owner":[],"postedDate":"January 13th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-03T13:11:23+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-13 08:28:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8554945","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8554945","identity":"rs-8554945","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}