Metal concentrations in various fish organs of different fish species from Poyang Lake, China

Carcinogenic and non-carcinogenic health risks associated with the consumption of fishes contaminated with heavy metals from Manzala Lake, Egypt

Manzala Lake was sampled to assess the concentrations and possible ecological risks of heavy metals. The mean heavy metal levels in the muscles of Nile tilapia, Flathead grey mullets and African catfish were 0.01, 0.15 and 0.29 mg/kg, respectively, for mercury; 3.16, 4.25 and 4.74 mg/kg for arsenic; 1.01, 0.87 and 0.95 mg/kg for lead; and 0.05, 0.12 and 0.06 mg/kg for cadmium. The levels of heavy metals exceeded their maximum permissible limits in most samples. The EDIs of some metals were higher than their PTDIs or BMDLs. The THQs and TTHQs from metal intake were >1 for Hg and Cd. In addition, the TCR values of As in all fish species were higher than 1.0 × 10-4 indicating a potential health risks from consumption of fish species which need strict hygienic procedures to prevent fish contamination with heavy metals and ensure that their levels did not exceed the maximum permissible limits.

Establishment of Indirect Competitive Enzyme-linked Immunosorbent Assay (ic-ELISA) for Copper ion (Cu2+) in Raw Meat Products

Adding an appropriate amount of copper to feed can promote the growth and development of livestock; however, a large amount of heavy metal copper can accumulate in livestock through the enrichment effect, which poses a serious threat to human health. Traditional Cu2+ detection relies heavily on complex and expensive instruments, such as inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS); thus, convenient and simple rapid detection technologies are urgently needed. In this paper, synthesized copper antigens were used to immunize mice and highly specific anticopper monoclonal antibodies were obtained, which were verified to exhibit high affinity and specificity. Based on the above antibodies, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for the rapid detection of copper content in pork. The standard inhibition curve of the method was obtained by antigen-antibody working concentration screening, in which the half inhibitory concentration (IC50) was 11.888 ng/mL, the limit of detection (LOD) was 0.841 ng/mL and the correlation coefficient R2 of the curve was 0.998. In the additive recovery experiment, the recovery rate ranged from 90% to 110%, and the coefficient of variation (CV) was less than 10%, indicating that the method achieved high accuracy and precision. Finally, the results of ic-ELISA combined with Bland-Altman analysis showed a high correlation with ICP-MS, and the correlation coefficient (R2) reached 0.990 when the copper concentration was less than 200 ng/mL. Thus, the ic-ELISA method exhibits high reliability.

Risk Assessment and Sources Apportionment of Toxic Metals in Two Commonly Consumed Fishes from a Subtropical Estuarine Wetland System

The widespread occurrence of heavy metals in aquatic environments, resulting in their bioaccumulation within aquatic organisms like fish, presents potential hazards to human health. This study investigates the concentrations of five toxic heavy metals (Pb, Hg, Zn, Cu, and Cr) and their potential health implications in two economically important fish species (Otolithoides pama and Labeo bata) from a subtropical estuarine wetland system (Feni estuary, Bangladesh). Muscle and gill samples from 36 individual fish were analyzed using energy dispersive X-ray fluorescence (EDXRF). The results revealed that the average quantities of heavy metals in both fishes' muscle followed the declining order of Zn (109.41-119.93 mg/kg) > Cu (45.52-65.43 mg/kg) > Hg (1.25-1.39 mg/kg) > Pb (0.68-1.12 mg/kg) > Cr (0.31-5.82 mg/kg). Furthermore, Zn was found to be present in the highest concentration within the gills of both species. While the levels of Cu, Zn, and Cr in the fish muscle were deemed acceptable for human consumption, the concentrations of Pb and Hg exceeded the permissible limits (>0.5 mg/kg) for human consumption. Different risk indices, including estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and carcinogenic or target risk (TR), revealed mixed and varying degrees of potential threat to human health. According to the EDI values, individuals consuming these fish may face health risks as the levels of Zn, Cu, and Cr in the muscle are either very close to or exceed the maximum tolerable daily intake (MTDI) threshold. Nevertheless, the THQ and HI values suggested that both species remained suitable for human consumption, as indicated by THQ (<1) and HI (<1) values. Carcinogenic risk values for Pb, Cr, and Zn all remained within permissible limits, with TR values falling below the range of (10-6 to 10-4), except for Zn, which exceeded it (>10-4). The correlation matrix and multivariate principal component analysis (PCA) findings revealed that Pb and Cr primarily stemmed from natural geological backgrounds, whereas Zn, Cu, and Hg were attributed to human-induced sources such as agricultural chemicals, silver nanoparticles, antimicrobial substances, and metallic plating. Given the significance of fish as a crucial and nutritious element of a balanced diet, it is essential to maintain consistent monitoring and regulation of the levels and origins of heavy metals found within it.

Mercury distribution, exposure and risk in Poyang Lake and vicinity, China

Mercury (Hg), especially methylmercury (MeHg), which is highly neurotoxic, is a global pollutant that can affect human health because of its accumulation in aquatic products. Poyang Lake, an inland lake in China, has been significantly affected by human activity, yet there is limited understanding of local mercury contamination and potential exposure pathways to humans. In this study, we explored the risks of mercury exposure by sampling sediments, plants, and aquatic organisms in the lake and surrounding areas and analyzing total Hg (THg) and MeHg levels. Sediment sampling was conducted at the main lake, rivers, rice paddies, and fishponds. Two dominant species of plants and 15 species of aquatic organisms were sampled and analyzed. We assessed the characteristics of mercury in sediments using the geo-accumulation index (Igeo), mercury exposure using the biomagnification factor (BMF) and biota sediment accumulation factor (BSAF), and risks using thresholds for adverse effects. The highest THg concentrations (137.04 ± 44.3 ng g-1 dw) were detected in the main lake sediments, whereas the highest MeHg concentrations (0.47 ± 0.6 ng g-1 dw) were detected in fishpond sediments. Mercury accumulation in the main lake sediments could be assessed as contaminated (Igeo > 0: 81.6%). Yellow catfish had the highest mercury concentration (THg 770.69 ± 199.7 ng g-1 dw; MeHg 741.93 ± 168.8 ng g-1 dw). Piscivores were adversely affected by carnivorous fish (50.8%), but all fish concentrations did not exceed the food safety standards recommend by China and the WHO. The mercury exposure results revealed significant Hg biomagnification and enrichment (BMF >1: 94.55%; BSAFmax = 1218). Long-term monitoring of aquatic organisms is warranted.

Health risk assessment of heavy metals in wild fish and seasonal variation and source identification of heavy metals in sediments: a case study of typical urban river in Xi'an, China

In order to determine the status of heavy metal pollution in river sediments and wild fish in Xi'an, concentrations of heavy metals (Cr, Ni, Cu, Zn, As, and Pb) were collected and analyzed in sediments and wild fish during dry season (October-November 2020) and wet season (June-July 2021). This study aimed to investigate the spatial and temporal variations of heavy metals in urban rivers of Xi'an, China. Their distribution characteristics and sources as well their pollution levels and health risks were assessed. The findings revealed that influenced by human activities, the heavy metal content in sediments (mg·kg-1 dry weight) in wet season was ranked as follows: Cr (73.09) > Zn (63.73) > Pb (40.31) > Ni (31.52) > Cu (24.86) > As (6.83); in the dry season: Zn (94.07) > Cr (69.59) > Cu (34.24) > Ni (33.60) > Pb (32.87) > As (7.60). Moreover, 32 fish samples from six species indicated an average metal content trend (mg·kg-1 wet weight) of Zn (8.70) > Cr (0.57) > Pb (0.28) > Ni (0.27) > Cu (0.24) > As (0.05). The potential ecological risk indices for sediment heavy metal concentrations in both seasons were well below the thresholds, which indicates that the aquatic environment is in safe level. The analysis of the potential ecological risk of sediment heavy metal concentrations indicates that the aquatic environment is safe for the time being. Based on the estimated daily intake (EDI), target risk quotient (THQ), total target risk quotient (TTHQ), cancer risk (CR), total cancer risk (TCR), and the permissible safety limits set by the agencies, the consumption of the fish examined is safe for human health. However, the presence of Cr and As in wild fish should still be a concern for human health, especially for children. The cumulative effect of heavy metals and the bioconcentration factor (BCF) suggest that sediment and heavy metals in fish are closely related, with higher concentrations in fish living in the bottom layer of the water column than in other water layers, and increasing with increasing predator levels. Correlation analysis and PMF modeling identified and determined four comparable categories of potential sources, namely, (1) atmospheric deposition and traffic sources, (2) agricultural sources, (3) industrial sources, and (4) natural sources.

Bioaccumulation of trace elements and hydrocarbons in chondrichthyans of the western Arabian Gulf: Environmental and human health risk assessment and implications for conservation

This is a first attempt to assess the levels of trace elements, PAHs, and TPHs in six elasmobranch species (Carcharhinus dussumieri, C. sorrah, Chiloscyllium arabicum, Gymnura poecilura, Sphyrna lewini, S. mokarran) from the Arabian Gulf. The chemical analysis showed that the concentrations of contaminants differed significantly between liver and muscle samples with both pelagic and benthic species and all families. For all species, contaminant concentrations were significantly higher in the liver than in the muscle. While muscle contaminant concentrations differed significantly with respect to species' lifestyles and families, those of liver showed no significant differences between pelagic and benthic species, neither between the four families nor between the six species. None of the analysed contaminants exceeded the internationally recognized standards in all studied species. These results enrich the knowledge on the bioaccumulation of contaminants in elasmobranchs and allow to assess the environmental status of the Arabian Gulf.

Heavy metals transport patterns and risk evaluation in the pig manure- black soldier fly-tilapia food chain

Black soldier fly (BSF) individuals can consume animal excrement and transform it into high-protein food that can be used for animals. This study investigated the changes in the levels of heavy metals (HMs) in BSF individuals and their growth related to ingesting pig manure. According to the trial findings, BSFs fed pig manure had the highest protein concentration of 21.98% and were the least expensive, and its HMs within an acceptable range. Tilapia grew the best when its feed contained half of BSF. Its single-tailed fish weight gain rate was 73.12%, and its survival rate was 100%. The total target hazard quotient (TTHQ) values of tilapia fed with various concentrations of BSF were 0.098-0.181, which were all <1. This indicated that there were no potential hazards posed to humans or the environment. This study offers fundamental information regarding the safety of BSF assessment as well as scientific backing for the widespread utilization of BSF, especially in the pig manure-BSF-tilapia food chain.

Heavy Metal Bioaccumulation in Highly Consumed Pelagic and Benthic Fish and Associated Health Risk

The present study investigated the levels of Manganese (Mn), Cadmium (Cd), Copper (Cu), Zinc (Zn), Lead (Pb) and Iron (Fe) in the tissues of a benthic fish (Clarias gariepinus) and a pelagic fish (Oreochromis niloticus), which are highly consumed in Ghana. The fish were collected from the Weija reservoir, which is an important source of fishery and potable water in Accra, Ghana. The results indicate heavy metal accumulation in all the tissues (gills, liver and muscles) analyzed. The bioaccumulation of all the metals was lowest in the muscles compared to the liver and gills in both species. The bioaccumulation of the metals was generally higher in the tissues of the catfish, except for Fe and Zn. Fe was higher in the gills and liver of the tilapia, and Zn was higher in the liver of the tilapia. The analysis of relationships between metal levels in the different tissues and the size of the fish showed a few significant correlations. The results also showed that all metals showed no potential health risk to consumers, as THQs and TTHQs in tilapia and catfish were less than one, and the metal levels in both species were all below the FAO/WHO maximum permissible limits.

Exposure status, spatial variation, and health risk assessment of selected heavy metal(loid)s in common commercial fish species of the Beibu Gulf

Fishes are considered as biological indicators of heavy metal(loid)s pollution. In this study, contents of seven heavy metal(loid)s, including Cu, Cr, Cd, Pb, Zn, As, and Hg, in the muscles of ten common fish species in the Beibu Gulf were analyzed to figure out the pollutants status and their health risk. Results showed all species were largely contaminated by arsenic. Under conservative estimation scenario, target hazard quotient and health index revealed no health risk of species except Alepes kleinii. Under pessimistic estimation scenario, target cancer risk and estimated daily intake showed that, except Saurida undosquamis, Saurida tumbil, and Trachinotus ovatus, the remaining species were at risk of causing cancer for their consumers. Daily intake of arsenic and mercury in most species by residents in the Beibu Gulf exceeded provisional maximum tolerable amount recommended by FAO, suggesting the need of moderate consumption of these species.

Effects of floods resulting from climate change on metal concentrations in whiting (Merlangius merlangus euxinus) and red mullet (Mullus barbatus) and health risk assessment

In this research, the effect of flooding caused by heavy precipitation, postulated to be one of the consequences of climate change, on toxic metal concentrations in two demersal fish species, whiting (Merlangius merlangus euxinus) and red mullet (Mullus barbatus), was investigated. For both demersal fish species, concentrations of Hg, Fe, Cd, Pb, Se, Al, Zn, Cu, Sr, B, Cr, Mn, Ni, Ba, and Li were compared between samples taken from Türkeli, Sinop, Black Sea, before and after the flood event in August 2021. Hg, Mn, Se, Li, B, and Sr metal concentrations increased in whiting and in red mullet in the post-flood samples. Estimated daily intake, target hazard quotient, cancer risk, the maximum allowable daily consumption rate and minimum daily requirements, and health risk analyses indicated that daily consumption of whiting and red mullet was risky due to the heavy metal Hg level after the flood. In addition, it was found that the samples had higher levels of Se than Hg, Se/Hg ratios were above 1, and Se-HBV were positive. Therefore, whiting and red mullet fishing should be restricted for a limited time period in the region.

Determining the trophic transfer of metal(loid)s and arsenic speciation in freshwater aquatic organisms by quantifying diet compositions

Bioaccumulation through diet is the predominant source of metal(loid)s in fishes; however, the trophic transfer of metal(loid)s from the diet to aquatic organisms remains largely unclear. In this study, aquatic organisms and five potential food sources (leaf litter, coarse and fine particulate organic matter (CPOM and FPOM, respectively), epilithon and fish) were collected around the Shimen Realgar Mine of China. Stomach content analysis and stable nitrogen and carbon isotope analysis, combined with a new Bayesian mixing model (MixSIAR), were used to quantify diet compositions of aquatic organisms. The δ¹³C and δ¹⁵N values varied among fish sizes and sampling sites and were probably related to the diet shift of aquatic organisms. The MixSIAR modelling results showed that the aquatic organisms' food sources were mainly composed of FPOM (9%-68%) and epilithon (15%-65%), with leaf litter, CPOM and fish accounting for smaller proportions (2%-30%). Concentrations ranged from 0.91 to 1298 mg/kg for As, 0.01-1.30 mg/kg for Cd, 0.12-37.79 mg/kg for Pb, 0.63-1158 mg/kg for Cr, 1.22-411 mg/kg for Cu, 0.82-1772 mg/kg for Mn, 0.31-542 mg/kg for Ni and 21.84-1414 mg/kg for Zn in all the collected samples, including the aquatic organisms and the relevant food sources. The metal(loid) concentrations in the CPOM, FPOM and epilithon were significantly higher than those in aquatic organisms and leaf litter. In addition, the biomagnification factors were all less than 1, indicating a biodilution from diet to freshwater organisms. The predominant As species were organic As in aquatic organisms, while inorganic As was common in their food sources, indicating that As biotransformation occurred within the freshwater food chain.

The application of chemometrics in metals source of identification in Brunei Bay surface sediment

Brunei Bay is a unique ecosystem which offers a vast biodiversity. This study was carried out to define the source of metals in the surface sediment of Brunei Bay to ensure the bay's health. The secondary data were analysed using chemometrics analysis to verify the possible factors that influence metals distribution in Brunei Bay sediment. Samples were collected several times during 2013 to 2014 using Ponar grab at 16 stations within the bay. Samples were then dried, pre-treated, digested and analysed using Inductively Coupled Plasma Mass Spectrometry (ICPMS) in the laboratory. Overall, the mean concentration of metal, sediment pH and clay fraction were significantly changed during different sampling periods, as the changes were presumed affected by seasonal changes. The Pearson correlation has pointed that metals were dominantly derived by natural input; however, the total organic carbon was proven to be derived by anthropogenic sources. Moreover, the principal component analysis has verified that the distribution of metals in the bay's sediment was dominantly influenced by natural processes. However, the utilization and manipulation of marine resources are slightly affecting the bay's ecosystem which may deteriorate the ecosystem health soon.

Metal pollution in freshwater fish: A key indicator of contamination and carcinogenic risk to public health

Metals are micropollutants that cannot be degraded by microorganisms and are infiltrated into various environmental media, including both freshwater and marine water. Metals from polluted water are absorbed by many aquatic species, especially fish. Fish is a staple food in the diets of many regions in the world; hence, both the type and concentration of metals accumulated and transferred from contaminated water sources to fish must be determined and assessed. In this study, the heavy metal concentration was determined and assessed in fish collected from freshwater sources via published literature and Estimated of Daily Intake (EDI), Target hazard quotient (THQ), and Carcinogenic Risk (CR) analyses, aiming to examine the metal pollution in freshwater fish. The fish was used as a bioindicator, and Geographic information system (GIS)was sued to map the polluted regions. The results confirmed that Pb was detected in fish sampled at 28 locations, Cr at 24 locations, Cu and Zn at 30 locations, with values Pb detected ranging from 0.0016 mg kg^-1 to 44.3 mg kg^-1, Cr detected ranging from 0.07 mg kg^-1 to 27 mg kg^-1, Cu detected ranging from 0.031 mg kg^-1 to 35.54 mg kg-¹, and Zn detected ranging from 0.242 mg kg^-1 to 103.2 mg kg^-1. The strongest positive associations were discovered between Cu-Zn (r = 0.74, p < 0.05) and Cr-Zn (r = 0.57, p < 0.05). Spatial distribution maps depicting the consumption of fish as food and its corresponding Pb and Cr intake revealed a higher incidence of both carcinogenic and non-carcinogenic health concerns attributed to Pb and Cr in the region with populations consuming the fish.

Metal Biological Enrichment Capacities, Distribution Patterns, and Health Risk Implications in Sea Bass (Lateolabrax japonicus)

Seabass (Lateolabrax japonicus) is a major aquacultured fish species worldwide. The bioconcentration, bioaccumulation, and biomagnification of metals in water, sediments, and commercial feed were investigated in L. japonicus from an aquaculture pond in the Pearl River Delta of South China. Aluminum (Al), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) were determined in the dorsal muscle, viscera, backbone, gill, and stomach contents of L. japonicus. The gill and stomach contents had higher levels of bioconcentration of most metals than other parts of fish. Based on the bioaccumulation factor, the gill and backbone exhibited the highest accumulation of Zn, while the viscera had the highest capacity to accumulate Cu. The mean biomagnification factor values exceeded for As in dorsal muscle, for Cu in the viscera, for Cr and Pb in the gill, and for Al, Cr, Fe, Cu, and Pb in the stomach contents, indicating efficient bioaccumulation from commercial feed and their habitat. Non-metric multidimensional scaling analysis revealed two groups that resulted from the accumulation of metals in various parts of L. japonicus. Moreover, health risk assessment indicated that no notable adverse health effects occurred from the ingestion of L. japonicus.

Health risk assessment of heavy metals (Zn, Pb, Cd, and Hg) in water and muscle tissue of farmed carp species in North Iran

This cross-sectional study was conducted to determine and compare the concentrations of heavy metals (Zn, Pb, Cd, and Hg) in carp-farming water and muscle of various carp species including common carp (Cyprinus carpio), bighead carp (Hypophthalmichthys nobilis), silver carp (Hypophthalmichthys molitrix), and grass carp (Ctenopharyngodon idella) collected from three major warm-water fish farms in Mazandaran Province (Iran) during March 2018 to March 2019. In addition, bioaccumulation of heavy metals (BCFs) and carcinogenic and non-carcinogenic risk assessments of consumers exposed to heavy metals through fish consumption were estimated. The water concentration of all metals in this study was lower than permissible limits. The concentration of Zn in the water (10.21-17.11 μg L^-1) was higher than that of other metals in all sites, followed by Pb > Cd > Hg. In fish muscle, Zn concentration in silver carp was the highest, and the lowest concentrations were related to Hg and Cd in common carp and grass carp, respectively. The target hazard quotients (THQ) indicated that the non-carcinogenic health risk to humans was relatively low by consuming four farmed carp species products. The carcinogenic risk of inorganic Pb was 1.24E-04 (common carp) to 2.11E-04 (grass carp) for adults, which is within the acceptable range. The values of BCFs for all metals demonstrated that farmed carp muscle could not be considered a bioaccumulative tissue for heavy metals. The results indicated that the concentrations of heavy metals in the farmed carp species in North Iran were relatively low and did not cause considerable human health risks.

Concentrations of heavy metals in water, sediments and aquatic organisms from a closed realgar mine

Mining activities can result in severe heavy metal contamination in freshwater ecosystems and lead to significant health risks. In this study, eight heavy metal concentrations in the water, sediments and aquatic organisms, including eighteen fish species, two shrimp species, one crab species and one amphibian frog species of the abandoned Shimen Realgar Mine area, were analysed. The results showed that most of the heavy metals detected in water, sediments and fish from the mine area were at relatively high levels, and historical realgar mining activities were a major source of arsenic (As) contamination in this area. We concluded that heavy metal bioaccumulation is species- and tissue-specific and is different for each element and sampling site. The concentration of heavy metals in fish was generally lower than that of the other aquatic organism species; these concentrations varied among different species with different feeding habits and habitats. The study showed that heavy metal concentrations were lower in muscle tissue than in other tissues (e.g. liver, skin, exoskeleton). A significant positive correlation between the As concentrations in sediment and fish was observed, indicating that sediment is an important factor affecting As accumulation in fish; thus, for fish protection, controlling the sources of water and sediment contamination is essential. Furthermore, the estimated daily intake (EDI) of all metals was acceptable, and the corresponding target hazard quotient (THQ) and total target hazard quotient (TTHQ) values were less than 1; hence, there was no serious health risk through fish consumption in this area.

Potentially Toxic Elements in Water, Sediments and Fish from the Karstic River (Raša River, Croatia) Located in the Former Coal-Mining Area

The assessment of the environmental quality of a sensitive karst aquatic system under the centuries-long anthropogenic influence of the coal mining industry is important for both improving the quality of water resources and protecting aquatic wildlife and human health. In this study, we investigated the anthropogenic impact on the aquatic environment of the upper and middle course of the Raša River through the analysis of a suite of metal(loid)s in three aquatic compartments (water, sediment, fish) using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of inorganic constituents in water were low, while the chemical composition of stream sediments mainly reflected the geological background of the area, indicating the origin of metal(loid)s from predominantly natural sources. Although comparison with PEC-Q values indicated that existing sediment quality conditions could pose a threat to benthic organisms with regard to Cr and Ni, the constant vertical profiles of these elements suggested their natural origin from the weathering of flysch. Element levels in the muscle of targeted fish species were in accordance with the values typical for low-contaminated freshwater systems, while levels of Cd, Pb and Hg were mostly below the European regulatory limits for toxic elements in foods, indicating that the low concentrations of most contaminants in muscles of fish from the Raša River do not present a risk to humans or other consumers. The obtained data indicated a generally low contamination status of the western part of the Raša River basin with regard to the analyzed inorganic elements.

Heavy Metals in Four Marine Fish and Shrimp Species from a Subtropical Coastal Area: Accumulation and Consumer Health Risk Assessment

Trace-element or heavy-metal pollution has emerged as a serious concern in terms of both environmental and human health issues. This study measured six trace and toxic heavy metals (Pb, Cd, Cr, Ni, Cu, and Zn) in four marine fish and shrimp species to assess their accumulation levels and evaluate the risks to human health. The mean concentrations of the metals in fish and shrimp species (Labeo bata, Sillaginopsis panijus, Platycepalus fuscus, and Penaeus monodon) followed the decreasing order of Zn (40.8 ± 9.7 μg/g) > Cu (17.8 ± 7.1 μg/g) > Pb (6.2 ± 1.8 μg/g) > Ni (0.4 ± 0.3 μg/g) > Cd (0.06 ± 0.02 μg/g > Cr (below detection level). Among the metals, only Pb in finfish and Pb, Cu, and Zn in shrimp samples exceeded the national recommended limits, representing possible risks to consumers. The mean metal concentrations in the studied fish/shrimp species followed the descending order of P. monodon > S. panijus > P. fuscus > L. bata, which implies that bottom dwellers and omnivores had higher levels of metals. However, the estimated daily intake (EDI) concentrations of Zn and Cu for the studied species were lower than the RDA (Recommended Daily Allowance). In addition, the Target Hazard Quotient (THQ) and hazard index (HI or TTHQ) values for all species were < 1, indicating that consumers might not experience carcinogenic health risks. A strong significant (p < 0.05) correlation between Cu and Pb (r = 0.623) and Zn and Cu (r = −0.871) indicated they were from the same source of origin. Cluster analysis (CA) and principal component analysis (PCA) demonstrated possible anthropogenic sources of toxic metals in the study area, specifically industrial wastes and agricultural chemicals.

Ecological and human health risk assessment of potentially toxic element contamination in waters of a former asbestos mine (Canari, Mediterranean Sea): implications for management

Between 1948 and 1965, the Canari asbestos mine (Corsica, France) discharged 11 million tonnes of serpentinite rubble into the sea. This study, therefore, aims to assess the environmental and health risks associated with contamination of potentially toxic elements using bioindicators (seagrass and fish) in the areas bordering the former mine within the perimeter of the Cap Corse and Agriate Marine Natural Park. The results and multivariate statistical analyses of the potentially toxic elements, made it possible to identify a concentration gradient, a model of bioaccumulation, and the occurrence of different groups, thus reflecting a spatial variation of the contamination. These results indicate that the former asbestos mine can still be considered, 55 years after its closure, as a major source of Co, Cr, and Ni for marine ecosystems and still influences the quality of the coastal area today. Our study, therefore, indicates that the two most polluted sites (Albo and Negru) are the closest stations to the south of the old Canary asbestos mine. According to the Trace Elements Pollution Index (TEPI) values, 6 species were classified as having a high contamination level: Scorpaena notata (1.37), Scorpaena porcus (1.36), Sepia officinalis (1.27), Diplodus vulgaris (1.02), Spicara maena (0.95), and Mullus surmuletus (0.94). Regarding the potentially toxic elements measured in the edible tissues of fish, the concentrations were all below the regulatory thresholds and did not reveal any potential risk to human health (Cd, Cu, Fe, Pb, Se, Sn, Zn). This work provides new and useful information to improve the monitoring of the environmental quality of a region characterized by previous mining activity and to assess the potential risk to human health due to the consumption of fish. Beyond the purely scientific aspects, these results could serve as decision support at the regional level for the definition of long-term public policies.

Occurrence, partition, and risk of four adjacent transition metals in seawater, sediments and demersal fish from the Pearl River Estuary, South China Sea

The spatio-seasonal variation, bioaccumulation and potential ecological risk of four metals (Co, Ni, Cu and Zn) in the multi-media of the Pearl River Estuary (PRE) were assessed. The degree of contamination and ecological risk of the four metals followed this pattern: Cu > Zn > Ni > Co, upstream > downstream, wet season > dry season. There were non-linear and linear correlations for Co, linear and non-linear correlations for Ni, and non-linear and no correlation for both Cu and Zn, between metals in bottom water or bioavailable concentrations in sediment and fish muscle. Co and Ni showed lightly polluted levels; Cu and Zn showed heavily polluted levels. This study demonstrates a tendency of cross-accumulation in fish of these four transition metals within specific habitats of the PRE.

Trace and rare earth element bioaccumulation in the spotted dogfish (Scyliorhinus stellaris)

Metals (trace elements and rare earth elements, REEs) were analysed by inductively coupled plasma-mass spectrometry in blood, the liver, the kidney and muscle of ex situ spotted dogfish (Scyliorhinus stellaris). The controlled environment in which these elasmobranchs were hosted allowed to assess a baseline level of metals in the different organs since exposure via water and food can be easily monitored. The highest arsenic, chromium, copper, and iron values were found in the liver, cobalt in the kidney, and cadmium and rubidium in muscle. The highest total trace elements content was found in the trend liver (75 mg kg^-1) > blood (33 mg kg^-1) > muscle (31 mg kg^-1) > kidney (10 mg kg^-1), while the ΣREEs was the liver (30 μg kg^-1) > muscle (15 μg kg^-1) > kidney (13 μg kg^-1) > blood (4.1 μg kg^-1). Between REEs, the most represented element was scandium. Significant differences in the concentration of metals among organs were observed for almost all elements. Nonessential elements were generally lower and essential elements higher in the examined specimens compared to wild elasmobranchs, suggesting a close relationship between a balanced diet and animal welfare.

Temporal distribution patterns of metals in water, sediment, and components of the trophic structure in a tropical coastal lagoon of the Gulf of Mexico

Trophic transfer and bioaccumulation of trace metals have a profound impact on the structure and function of coastal areas; however, the metal accumulation patterns in detritus-based food webs and the influence of climatic variability have not been thoroughly investigated. The Tampamachoco Lagoon (Gulf of Mexico) is a coastal system impacted by emissions from a thermoelectric plant. We evaluated the spatial-temporal distribution patterns of Al, Cd, Hg, Cr, Cu, and Pb in water, sediments, and in organisms categorized by trophic levels (TLs), trophic guilds, and habitat preferences. The sediments had the highest concentrations of metals with no significant differences between seasons. The indices of geo-accumulation and potential ecological risk classified sediments as "moderately contaminated", evidencing a threat to human health through consumption of detritivores and filter-feeders. The lowest TLs (filter-feeders and detritivorous) reached the maximum Metal Pollution Index in the rainy season. According to discriminant analyses of metals and species, omnivorous and zoobentivorous organisms were associated with Hg during the rainy and dry seasons; while Al, Cd, and Cu were related to low TLs, and seston was associated with Pb. Food web magnification factor analysis showed that: (a) Pb, Cu, and Cr were biodiluted as trophic levels increased; (b) Cd and Hg showed temporal biomagnification trends; (c) Al, Pb, Cu, and Cd showed significant biodilution from the lowest TL to intermediate TLs; and (d) Hg was transferred from the lowest to intermediate TLs with clear biomagnification effects.

Bioaccumulation and Heavy Metal Contamination in Fish Species of the Dhaleswari River of Bangladesh and Related Human Health Implications

The release of a large quantity of heavy metals into the Dhaleswari River from the tannery, dyeing, and other industrial setups and their subsequent transfer to food chains through fish consumption have been an alarming issue in Bangladesh. To study the pollution level, a total of seven fish species, namely Heteropneustes fossillis, Channa punctata, Nandus nandus, Chanda nama, Anabas testudineus, Mystus gulio, and Colisa fasciata, were collected in winter from the Dhaleswari River and the total concentrations of Cr, Pb, Ni, and Zn in head and body tissues were analyzed separately. The concentrations of Cr, Pb, and Zn were found 300, 20, and 10 times higher, respectively, than the guideline value of the Food and Agriculture Organization (FAO)/World Health Organization (WHO), indicating possible health risks to humans. In most cases, bioaccumulation factors (BAFs) exceeded the highest limit, expressing that most of the species, especially C. nama, A. testudineus, and C. fasciata, were in the highly bioaccumulative state. The health risks associated with fish consumption were determined in terms of estimated daily intake (EDI), non-carcinogenic risks (THQ), and carcinogenic risk (TR) factors. The THQs for Cr and Pb crossed the maximum value of 1 in all the fish species except Pb in Mystus gulio, which might cause different non-carcinogenic diseases upon consumption of these fishes. In all the fish species, the carcinogenic risk factor for Cr exceeded the standard value (10^-4), indicating chronic cancer risk to humans. Although the estimated daily intake (EDI) values did not cross the permissible limit, continuous consumption of contaminated fish from the target area may cause serious health complications. This study revealed that consumption of these fishes exposed people to a higher risk of non-carcinogenic and carcinogenic consequences in terms of human health.

Consumption of metal-contaminated shellfish from the Cuddalore coast in Southeastern India poses a hazard to public health

Seasonal distribution of four metals (Cd, Cu, Pb, and Zn) in eight shellfish species collected from the heavily contaminated Cuddalore coast in Tamil Nadu, Southern India, were analyzed. Metal concentrations in all shellfish species were determined using atomic absorption spectrometry. All metals were present in all seasons in most of the species, however, with a few exceptions. Overall, the metal concentration was in the descending order: Zn > Cu > Pb > Cd. Metals might have emerged from both natural and anthropogenic sources as per multivariate statistical analysis. Bioaccumulation factor results showed that cadmium was more bioaccumulated and beyond the threshold limit. Hazard index (HI) values revealed that consuming shellfish from Cuddalore coast can pose hazards to human health, with all HI values beyond threshold limit across all seasons - premonsoon (1.33), monsoon (1.73), postmonsoon (2.55), and summer (2.64). It is evident that consumption of shellfish across all seasons may have adverse health impacts to the people.

Dataset-based assessment of heavy metal contamination in freshwater fishes and their health risks

The ecological risks and health hazards of heavy metals pollution in Taihu Lake have received widespread concern. This study has developed a species-pollution dataset which includes a large amount of data on heavy metal pollution in Taihu fish. The heavy metal contamination poses a significant threat to human consumption, but no studies have been conducted to assess the risk of exposure to consumption of these fish and to make recommendations for their consumption. In this study, we systematically integrated the relevant data in the dataset, analyzed its contamination level using PI (single pollution index) and MPI (metal pollution index) models, and assessed health hazards of fish consumption using THQ (target hazard quotient) and ILCR (incremental lifetime cancer risk) models. Results showed that the contamination levels of heavy metals in fish varied in a feeding habit and living habit dependent manner. The risk of non-cancer health is the highest from consuming omnivorous fish, then from carnivorous and herbivorous fish. The ILCR model predicted that the long-term Taihu consumption of omnivorous fish may pose a potential carcinogenic risk, especially for children. In all, our study provided a comprehensive understanding on the risk of heavy metals in Taihu. Accordingly, it is recommended that children should try to choose herbivorous fish when consuming fish from Taihu Lake while avoiding long-term consumption of omnivorous fish.

Ecological and Human Health Risk Assessment of Heavy Metals in Cultured Shrimp and Aquaculture Sludge

Shrimp is one of the major export products in South Asian countries and also an eminent source of nutrition for humans. Hence, any negative effect of this industry may affect not only the country’s economy but also human health. Therefore, in this study, we aimed to assess heavy metal contamination and associated human health risks in cultured shrimp (Penaeus monodon) and aquaculture sludge collected from three shrimp farms of the Cox’s Bazar district, Bangladesh. The results showed that among the eight metals studied, Pb (17.75 ± 1.5 mg/kg) and Cu (9.43 ± 2.8 mg/kg) levels in all shrimp samples were higher than the recommended limit, whereas the concentrations of Cd (0.09 ± 0.03 mg/kg), Mn (4.83 ± 2.2 mg/kg), As (0.04 ± 0.02 mg/kg), Hg (0.02 ± 0.006 mg/kg), Zn (18.89 ± 2.9 mg/kg) and Cr (0.69 ± 0.6 mg/kg) were within the permissible level. The concentrations of Mn (1043.37 ± 59.8 mg/kg), Cr (30.38 ± 2.1 mg/kg), Zn (74.72 ± 1.13 mg/kg) and Cu (31.14 ± 1.4 mg/kg) in the sludge of all farms were higher than the recommended limit, whereas the concentrations of Pb (20.23 ± 1.9 mg/kg), Cd (0.09 ± 0.2 mg/kg), As (0.44 ± 0.34 mg/kg) and Hg (0.08 ± 0.02 mg/kg) in all sludge samples were lower than the threshold limits. However, the estimated daily intake (EDI), targeted hazard quotient (THQ) and hazard index (HI) assessed for potential human health risk implications suggested that Pb and Cr may pose non-carcinogenic health effects, although carcinogenic risks (CR) values were acceptable for consumers. However, the pollution load index (PLI) of the studied area was below 1, which indicates low deterioration of the area. Geoaccumulation index (Igeo) and contamination factor (CF) analyses revealed that study area is unpolluted and sludge is enriched with metals in the following order: Mn > Zn > Cu > Cr > Cd > Hg > Pb > As.

Metals Bioaccumulation in 15 Commonly Consumed Fishes from the Lower Meghna River and Adjacent Areas of Bangladesh and Associated Human Health Hazards

The lower Meghna River, the easternmost part of the Ganges Delta, faces severe anthropogenic perturbations as it receives a huge discharge and industrial effluents. To measure the metal concentrations and human health hazards, edible tissues of 15 commercially important fish species were collected from the local fish markets and the lower Meghna River, Bangladesh. Trace and heavy metals such as Pb, Cr, Cu, Zn, Mn, Fe, Hg, Ni, Ca, Co, Se, Rb, Sr, and As were detected using the Energy Dispersive X-ray Fluorescence (EDXRF) method. The hierarchy of mean metal concentrations obtained was: Fe (162.198 mg/kg) > Zn (113.326 mg/kg) > Ca (87.828 mg/kg) > Sr (75.139 mg/kg) > Cu (36.438 mg/kg) > Se (9.087 mg/kg) > Cr (7.336 mg/kg) > Mn (6.637 mg/kg) > Co (3.474 mg/kg) > Rb (1.912 mg/kg) > Hg (1.657 mg/kg) > Ni (1.467 mg/kg) > Pb (0.521 mg/kg) > As (BDL). Based on the metal concentration obtained, the carnivorous species contained more metals than omnivores and herbivores. Similarly, the euryhaline and benthic feeder fishes had more metals than the stenohalines and demersal fishes. The metal pollution index (MPI) suggested that the highly consumed fish species Tilapia (Oreochromis mossambicus) and Rui (Labeo rohita) accumulated higher metals than other fishes. Both the Targeted Hazard Quotient (THQ) and Hazard Index (HI) values for adult and child consumers were <1, indicating that consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, carcinogenic risk (CR) exposure of Cr for all the consumers was found in the acceptable range (10−6 to 10−4), but the CR exposure of Pb was negligible for all the consumers. The correlation, principal component analysis (PCA), and cluster analysis were conducted to identify the sources of metals identified from the fish tissue. The results indicated that the probable sources of the pollutants were anthropogenic, arising from agricultural activities, electroplating materials, and lubricants used near the study area. However, the present study showed a different metal concentration in the samples at different levels but within the threshold levels non-carcinogenic and carcinogenic health risks; hence, the fishes of the area, in general, are safe for human consumption.

Probabilistic public health risks associated with pesticides and heavy metal exposure through consumption of common dried fish in coastal regions of Bangladesh

The chemical contaminants in dried fish are of great food safety concern and an emerging public health issue in Bangladesh. The aim of this study was to assess the public health risk associated with exposure to pesticides (organochlorine and organophosphorus) and heavy metals (lead, mercury, cadmium, chromium, arsenic) through the consumption of dried fish (Bombay duck, ribbon fish, silver jewfish, shrimp, Chinese promfret) in coastal districts (Cox's Bazar, Chittagong, Bhola, Patuakhali, Khulna) of Bangladesh. Dried fish consumption data were collected from 500 adult respondents (100 from each district) using a food frequency questionnaire (FFQ). Pesticide residues were determined using QuEChERS extraction coupled to gas chromatography and gas chromatography mass spectrometry, and heavy metals were estimated using an atomic absorption spectrophotometric method. The results revealed that the frequency and amount of dried fish consumption was highest for Bombay duck in Cox's Bazar (11.57 g/capita/day) and ribbon fish (12.10 g/capita/day) in Chittagong. The estimated daily intake (EDI, 7.40 × 10^-5 to 1.10 × 10^-4 mg/kg/day) and health risk index (HRI, 0.013 to 0.16) values expressed no health risk from pesticide residues in all the positive samples. For heavy metals, target hazard quotients (THQ) for non-carcinogenic health risk were below 1 (0.001-0.154), indicating no health risk for all samples. However, carcinogenic risk R value indicated a potential health risk for chromium (2.64 × 10^-6 to 4.06 × 10^-6), and carcinogenic R_T value (2.82 × 10^-6 to 5.71 × 10^-6) indicated a potential health risk for all the metals. It is concluded that the risk of exposure to pesticides through the consumption of dried fish is low, while heavy metals pose moderate-to-high health risks to dried fish consumers in the study area. Thus, the study suggests an appropriate risk management policy that controls pesticides and heavy metals in dried fish to ensure safe food for local and global consumers, underpinned by a producers' capacity building and consumers' awareness raising strategy.

Bioaccumulation and human health risks of potentially toxic elements in fish species from the southeastern Carajás Mineral Province, Brazil

Anthropogenic activities may have increased the concentrations of potentially toxic elements (PTEs) in fish from the southeastern Carajás Mineral Province in Brazil, which has not yet been studied. The objectives were to determine the quality parameters of surface water and bottom sediments, and to assess the bioaccumulation and risks of Al, Fe, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Ti, V and Zn in fish species from the southeastern Carajás Mineral Province. Water, sediments and fish species (Colossoma macropomum, Curimata cyprinoides, Geophagus sp., Leporinus trifasciatus, and Serrasalmus eigenmanni) were collected in 14 areas in the municipalities of Parauapebas, Marabá and Canaã dos Carajás, contemplating the Gelado Stream and the Parauapebas, Tapirapé and Itacaiúnas Rivers. Water samples were subjected to physicochemical analysis using a multiparameter meter. Concentrations of PTEs in all samples were quantified by inductively coupled plasma-optical emission spectrometry. Enrichment factor (EF) and geoaccumulation index (Igeo) were calculated to study the sediment enrichment and contamination. Ecological and human health risk assessments were performed to determine the risks to the environment and population's health. EF and Igeo revealed that the sediments from the Parauapebas River and Gelado Stream are respectively enriched by Ba, Co, Cu, Cr, Mn, Pb, and Ba, Co, Cr, Ni, Pb and V. The concentrations of Fe (1.67 mg L^-1) and Mn (0.11 mg L^-1) in water and the concentrations of Cr (>0.1 mg kg^-1) and Pb (>2 mg kg^-1) in fish were above the Brazilian legislation thresholds. The ecological risk assessment revealed considerable risk from Ni and moderate risk from multiple PTEs in sediments from the Gelado Stream. Human health risks were detected for Pb in all fish species and for Mo in L.trifasciatus. These results indicate that techniques for monitoring and controlling contamination must be implemented by the environmental agencies.

Fishery Status and Rebuilding of Major Economic Fishes in the Largest Freshwater Lake in China Based on Limited Data

Poyang Lake, the largest freshwater lake in China, possesses abundant fishery resources, but its fish stock status is still unclear. In this work, the stock status of and fishing efforts of nine major economic fishes in the Poyang Lake were estimated from 2000 to 2019 with a catch-based maximum sustainable yield (CMSY) model based on catch and resilience data. It was further predicted whether the biomass of those fishes could be restored to support maximum sustainable yield (Bmsy) under the policy of “Ten years fishing moratorium in the Yangtze River”. The results showed that goldfish Carassius auratus, grass carp Ctenopharyngodon idella, and black carp Mylopharyngodon piceus suffered from higher fishing efforts and low biomass in the past 20 years; bighead carp Hypophthalmichthys nobilis, yellow catfish Tachysurus fulvidraco, and common carp Cyprinus carpio responded differently to their fishing efforts; silver carp Hypophthalmichthys molitrix, Amur catfish Silurus asotus, and mandarin fish Siniperca chuatsi were underexploited. Six species were overfished in 2019, and their biomass would be expected to recover for sustainable exploitation during the fishing moratorium, except for M. piceus. This study provided a case study of feasible freshwater fishery evaluation in limnetic ecosystems.

Health benefits and risks associated with element uptake from grilled fish and fish products

BACKGROUND

The content of essential and toxic elements in grilled fish (Atlantic salmon, trout) and in 20 assortments of fish products was examined. The aim of this study was to assess the fulfilment of the demand for Zn, Fe, Mn and Cu based on recommended dietary allowances (RDAs) or adequate intakes (AIs) and to assess the health risk associated with the consumption of Al, Pb and Cd. The risk assessment was based on estimated weekly intake (EWI), hazard index (HI), target risk ratio (THQ) and percentage: provisional tolerable weekly intake (PTWI) for Al, tolerable weekly intake (TWI) for Cd and reference dose lower bound (BMDL) for Pb.

RESULTS

Taking into account the health benefits, the best source of Fe, Cu and Mn was found to be fish products in cans and jars, 150 g of which covered the daily requirement: Fe 9.39%, Cu 2.91% and Mn 1.21%. Smoked fish covered the RDA for Zn to 5.69%. Moreover, the uptake of toxic elements was as follows: Al 0.45% PTWI: Pb 0.74% BMDL10 and Cd 2.20% TWI. The THQ values for Pb and Cd were significantly lower than 1, whereas for Al it reached as high as 4.0.

CONCLUSION

The obtained results indicate that there is no risk related to the intake of Pb and Cd with the consumption of the tested fish products. Low consumption of fish by Poles, however, contributes to their small share in covering the demand for microelements, i.e. Zn, Fe, Mn and Cu. © 2021 Society of Chemical Industry.

Assessment of heavy metal accumulation in freshwater fish of Dongting Lake, China: Effects of feeding habits, habitat preferences and body size

We measured the concentrations of Cr, Fe, Ni, Cu, Zn, Cd, Pb and Hg, and the stable isotope ratios (δ¹³C and δ¹⁵N) in 87 fish samples within 12 economic fish species collected from the Dongting Lake, the second largest freshwater lake in China. With few exceptions in concentration of Cr, most of fish species showed lower concentrations of the 8 metals than legislation thresholds. Piscivorous fishes had significantly higher values of δ¹⁵N (possessing higher trophic level) and metal concentrations than planktivorous and herbivorous fishes. Moreover, demersal fishes showed higher concentrations of Cu, Zn, Cd and Pb than pelagic and benthopelagic fishes. We found positive correlations between concentrations of Fe, Pb and Hg and δ¹⁵N ratio, confirming the biomagnification of the three metals through trophic transfer. In contrast, fishes showed clear growth dilution effect for Ni, Zn, Cu, Pb and Hg, indicated by the negative correlations between their concentrations and fish weight or length. Multiple regression analysis demonstrated that growth dilution and biomagnification effects simultaneously governed the metal concentrations in fish muscle, and the two effects' importance varied among different metals. The human health risk assessment indicated that all 8 metals gave target hazard quotient (THQ) values < 1.0, i.e., the estimated daily intake (EDI) of metals did not exceed the oral reference dose (RfD), indicating a safe consumption of these fish species for consumer. Our study provides comprehensive approaches to better understand the determining processes and potential risk of heavy metals in freshwater lake fishes.

Health risk assessment and bioaccumulation of heavy metals in Procambarus clarkii from six provinces of China

Contamination with heavy metals in wild red swamp crayfish (Procambarus clarkii) from 7 different geographical areas in six provinces of China (Hubei, Hunan, Jiangxi, Anhui, Jiangsu, and Shandong) was evaluated. Concentrations of chromium (Cr), arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg) in the abdominal muscle, gonad, and hepatopancreas were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometer (AFS). Except for the Cd content in the hepatopancreas, the contents of selected heavy metals in three different tissues were significantly lower than the proposed limits provided by United States Environmental Protection Agency (USEPA). The maximum accumulations of Cd and Pb were in the hepatopancreas, while the maximum accumulation of As was in the gonad, and the maximum accumulations of Hg and Cr were in the abdominal muscle. The highest contents of Cr, Hg, and Pb were all detected in Dongting Lake, Hunan, which was consistent with the trend of the metal pollution index (MPI). Risk value of the target hazard quotient (THQ) was below 1.0, suggesting that the intake of selected heavy metals through crayfish consumption would not pose a significant health risk to consumers.

Water, sediments and fishes: First multi compartment assessment of metal pollution in a coastal environment from the SW Atlantic

This is an integrated assessment of the distribution of Cd, Cr, Hg and Pb in dissolved water, sediments and muscle fish tissues (Cynoscion guatucupa, Micropogonias furnieri, Mustelus schmitti and Ramnogaster arcuata) from the Bahía Blanca estuary, Argentina. Within the water fraction (μg L^-1), Hg and Pb concentrations ranged from below the limit of detection (<LOD) to 0.53 and 54, respectively. For Cd and Cr, values varied from 0.060 to 0.56 and from 1.6 to 18, respectively. In the sediment fraction (μg g^-1) values ranged from <LOD to 0.21 and 0.47 for Cd and Hg, respectively, from 11 to 18 for Cr and from 5.1 to 10 for Pb. Metals in fish muscle tissues (μg g^-1) ranged from <LOD to 2.8, 0.53 and 0.52 for Cr, Hg and Pb, respectively. All Cd values were <LOD. This marine environment is potentially vulnerable to anthropogenic pollution since dissolved Cr, Hg and Pb values exceeded established environmental quality guidelines. Moreover, the sediment pollution indices indicated a deterioration of the estuarine environment, with Cr and Pb associated to anthropogenic impacts, whereas Hg could be occasionally associated with adverse biological effects. The biota to water accumulation factor (BWAF) reflected that fish species showed potential to accumulate Cr (BWAF: 73-510) and, especially, Hg (BWAF: 1000-8000). The high biota to sediment accumulation factor found for Hg (up to 9.8) indicated that fish species behaved as macro or micro concentrators. These results highlights the importance of a multi compartment approach in pollution assessment, with implicances for future works.

Bioaccumulation of heavy metals in fish species of Iran: a review

Accumulation of heavy metals (HMs) in fish tissues is an important factor in monitoring the health and safety of aquatic ecosystems. Furthermore, fish are important parts of aquatic food chains and play a significant role in human health. Considering the significant role of fish in the diet of humans and their ability to transfer and biomagnify HMs, it is necessary to determine and study these contaminants in fish tissues, especially in the edible parts of the fish. In addition to the other ecological and economic services of aquatic ecosystems, water bodies, especially the Persian Gulf in the south and the Caspian Sea in the north of Iran, are the main sources of seafood for people in nearby areas, as well as people living farther away who have gained access to seafood due to the extensive trade of aquatic organisms. This study provides an overview of the health conditions of the aquatic ecosystems in Iran by monitoring HM bioaccumulation in fish species. For this purpose, we reviewed, summarized, and evaluated papers published on HM concentrations in fish species from different aquatic ecosystems, including the Persian Gulf, the Caspian Sea, wetlands, rivers, qanats, water reservoirs, lakes, and dams, with emphasis on species habitats, feeding habits, and target organs in accumulation of HMs. Generally, the highest concentrations of HMs were observed in fishes collected from the Persian Gulf, followed by species from the Caspian Sea. Species inhabiting the lower zone of the water column and carnivorous and/or omnivorous species showed the highest levels of HMs. Moreover, liver was the main accumulator organ for HMs.

Potential health risk assessment of some bioaccumulated metals in Nile tilapia (Oreochromis niloticus) cultured in Kafr El-Shaikh farms, Egypt

In Egypt, using agricultural drainage water is a serious challenge for fish farming, due to water scaristy. Metals could be a potential threat to the quality of the cultured fish. Thus, this study aimed to assess the content of the metals in the cultured fish, their effect on the fish tissues, and the possible human health risk upon their consumption. This accomplished firstly, by determining the levels of essential Fe, Mn, Zn, Cu, beside the top three most toxic metals (Cr, Cd, and Pb) in the edible muscles and liver of 200 samples of Oreochromis niloticus cultured at three fish farms, using inductively coupled plasma optical emission spectroscopy (ICP-OES). The results showed the order of abundance: Fe > Zn > Cu ≥ Cr > Mn > Pb > Cd. Levels of Fe, Zn, Mn, and Cu in the fish liver were higher than corresponding values of muscles by 3, 3, 5, 9 order of magnitude, respectively. The histopathological examination showed alternations in muscles and liver tissues of fish farms irrigated with drainage water. However, the risk assessment indicated the safe human consumption of cultured fish produced from these fish farms.

Levels and health risk assessment of heavy metals in dried fish consumed in Bangladesh

As a cheap source of high-quality protein, healthy fats and essential nutrients, dried fish is a common item in the daily diet of the Bangladesh populace. In this study, ten types of widely consumed dried fish (H. neherius, T. lepturu, P.chinensis, P. affinis, A. mola, P. microdon, I. megaloptera, C. dussumieri, L. calcarifer, and G. chapra) were analyzed for Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Hg, Pb, Ni and As by using an Energy Dispersive X-ray Fluorescence (EDXRF) technique. The concentration of the studied metals was found in the order Fe > Zn > Hg > Cu > Se > Cr > Mn > Co > Rb > Pb, while As and Ni were below the limit of detection. All fish species showed moderate to high pollution, where the species H. Neherius and P. Chinensis are the most and least polluted ones, respectively. The probable source of contamination is the leaching from the drying pans into the fish samples, atmospheric deposition, anthropogenic contamination, etc. of the water body where these fish were harvested. The calculated hazard index for the general population was below the maximum limiting value (i.e., < 1) except for Hg to children. The carcinogenic risk showed values lower than the acceptable limit for cancer risks (10^–6 to 10^–4). Periodic monitoring of trace metals in the aquatic organisms along with fish is recommended to avoid any unexpected health hazards caused by the toxic heavy metals via fish consumption.

Metal Bioaccumulation in the Gill, Liver, and Muscle of Bluefish (Pomatomus saltatrix) From the Northeastern Mediterranean and Human Health Risk Assessment Associated with Their Seasonal Consumption

Heavy metals are continuously released into the oceans from both natural and anthropogenic sources. They are serious threats to both ecosystem and human health because of their toxicity, persistence, bioaccumulation, and biomagnification. We present metal concentrations in the economically important bluefish from Iskenderun Bay, providing valuable information on Northeastern Mediterranean aquatic ecosystem health, as well as the human health risk. The concentrations of manganese, iron, copper, zinc, selenium, cadmium, lead, and mercury were determined in the gill, liver, and muscle tissues of bluefish (Pomatomus saltatrix) caught in Iskenderun Bay (Turkey) during four seasons. Samples were analysed via inductively coupled plasma mass spectrometer. Fe and Zn were detected in the highest concentrations during all four seasons. The ranges of Fe concentrations were 61.15-108.76, 229.78-377.02, and 6.35-8.63 and those of Zn were 25.21-44.25, 42.25-76.08, and 6.27-13.59 in the gills, livers, and muscles, respectively. In contrast, Hg and Cd were not found in the bluefish tissues in any season with the exception of Cd in the gills during the spring (0.757 mg/kg, above the legal limit of 0.5 mg/kg). On a seasonal basis, no meaningful accumulation trend was observed for the muscles or gills, while the highest concentrations of Mn, Fe, Cu, Zn, and Se in the liver were found in the spring. Liver tissues possessed higher metal concentrations than gill and muscle tissues. Estimated daily and weekly intakes of the metals due to human consumption of the bluefish were considerably lower than the provisional tolerable intake. In this study, there was an inflow of metals into Iskenderun Bay; however, no significant metal accumulation was found in bluefish tissues at a rate that would harm human health.

Comparative transcriptome analyses of the liver between Xenocypris microlepis and Xenocypris davidi under low copper exposure

Copper is one of the most ubiquitous environmental pollutants worldwide. Previous studies have focused on the toxicology of high copper exposure, while there has been comparatively less research on the biological effects of low copper exposure. Low concentrations of copper often exist in freshwater ecosystems, and its impact on the fish is unclear. Both Xenocypris microlepis and Xenocypris davidi are bottom-feeding fishes widely distributed in freshwater ecosystems of China, and they are more likely to be contaminated by low concentrations of copper. Low copper exposure may have effects on molecular regulation at the level of gene expression in the two Xenocypris species. To investigate gene expression differences involved in the response to low copper concentrations between X. microlepis and X. davidi, we established the responses to low copper exposure of 0.01 mg/L for 14 days at the transcriptional level, and RNA-Seq was used to perform a comparative transcriptomic analysis of the liver. A total of 74,135 and 60,894 unigenes from X. microlepis and X. davidi were assembled by transcriptome profiling, respectively. Among these, 84 genes of X. microlepis and 165 genes of X. davidi were identified as differentially expressed genes (DEGs). There were 60 and 135 up-regulated, 24 and 30 down-regulated genes in the two species, respectively. Comparative transcriptome analyses identified five differentially co-expressed genes (DCGs) related to low copper exposure from the DEGs of the two Xenocypris species. The five DCGs were related to the fishes' growth, antioxidant system, immune system and heavy metal tolerance. The results could help us to understand the molecular mechanisms of the response to low copper exposure, and the data should provide a valuable transcriptomic resource for the genus Xenocypris.

Bioaccumulation and human health risk assessment of trace metals in the freshwater mussel Cristaria plicata in Dongting Lake, China

Trace metal contamination in water and bioaccumulation in aquatic organisms are human health risks of increasing concern. However, the bioaccumulation of trace metals in the organs of the mussel Cristaria plicata in Dongting Lake, China and the human health risks of mussel consumption are largely unknown. We investigated the concentrations of 15 trace metals and metalloids in surface water, sediments, and C. plicata organs (foot, gill, mantle, and visceral mass) and quantified the bioaccumulation and human health risk of these trace metals in specimens collected from Dongting Lake. The concentrations of most metals in surface water exceeded previously published background values. In contrast, the concentrations of most metals in sediments showed a decreasing trend. Overall, the metal concentrations in the gill and visceral masses of C. plicata were higher than those in the foot and mantle, and higher bioaccumulation capacities were observed for essential metals than for nonessential metals. The mean concentrations of the trace elements Zn, Pb, Cd, As, Cu, and Cr in C. plicata foot samples were lower than the threshold values established by international and Chinese organizations. The estimated daily intake (EDI) values of the essential metal Mn in C. plicata foot was higher than the recommended tolerable daily intake (TDI) values for juveniles. Only Mn for juveniles and As for both juveniles and adults may pose noncarcinogenic health risks through foot consumption. The hazard index (HI) values for adults and juveniles were higher than 1, suggesting significant risks of noncarcinogenic effects to humans by exposure to multiple metals.

Heavy metal pollution and stable isotope ratios (δ13C and δ15N) in marine organisms from the Northern Beibu Gulf, South China Sea

Twenty biota species were collected from the Northern Beibu Gulf to understand the heavy metal pollution status and biomagnification characteristics. Mean concentrations (μg/g) of Mn, Zn, Pb, Cr, Ni, As, Cu, and Cd in the biota species were 0.99, 38.33, 0.14, 0.079, 0.085, 51.10, 7.92, and 0.21, respectively. As levels in most biota species exceeded the corresponding guidelines. Crabs were detected with high metal accumulation ability for each heavy metal except Pb. The ranges of δ¹⁵N and δ¹³C in organisms were from 8.0‰ to 15.6‰ and from -21.4‰ to -15.6‰, respectively. Cr, Mn, Ni, and As showed potential biomagnification trends in the food webs. The EDI values of these elements decreased by the sequence of As > Zn > Cu > Mn > Cd > Pb > Ni > Cr. High THQ and CR values for As indicated a potential health risk by consumption of these aquatic products.

Assessment of potential human health risk due to heavy metal contamination in edible finfish and shellfish collected around Ennore coast, India

This study aims to estimate anthropogenic sources of pollutants such as heavy metals that pollute or poison the commercial marine finfish and shellfish present around the Ennore coastal area and to identify, quantify and manage the associated risks for the betterment of society. The levels of toxic heavy metal concentrations from monitoring and surveillance of copper, chromium, cadmium, mercury, lead and zinc heavy metals were estimated from water, sediment and commercial marine finfish and shellfish samples that were collected for study. The individual mean bioaccumulation index (IMBI) and Metal Pollution Index (MPI) values varied between finfish and shellfish. Target hazard quotient (THQ) index values were calculated, and copper and zinc were found to be elevated at levels affecting children in particular. Thus, efforts are urgently needed to resolve the current and potential risks associated with the negative impact of heavy metal intake from seafood on human health. This study attempts to identify levels of metal contamination and corresponding risk factors with regard to human health.

Combining metal and stable isotope analyses to disentangle contaminant transfer in a freshwater community dominated by alien species

Freshwater ecosystems are negatively impacted by various pollutants, from agricultural, urban and industrial wastewater, with metals being one of the largest concerns. Moreover, freshwater ecosystems are often affected by alien species introductions that can modify habitats and trophic relationships. Accordingly, the threat posed by metals interacts with those by alien species, since the latter can accumulate and transfer these substances across the food web to higher trophic levels. How metals transfer within such communities is little studied. We analysed the concentration of 14 metals/metalloids (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, Zn, hereafter 'metal(s)') of eight fish and three crustacean species co-existing in the Arno River (Central Italy), most of which were alien. To assess the pathway of contaminants within the community, we coupled metal analysis with carbon and nitrogen stable isotope analysis derived from the same specimens. Crustaceans showed higher metal concentration than fish, except for Cd, Hg and Se that were higher in fish. We found evidence of trophic transfer for six metals (Cd, Cr, Hg, Mg, Se, Zn). Additionally, ontogenetic differences and differences among various fish tissues (muscle, liver, and gills) were found in metals concentration. Considerable biomagnification along the trophic chain was found for Hg, while other metals were found to biodilute. Using stable isotopes and Hg as a third diet tracer, we refined the estimations of consumed preys in the diet previously reconstructed with stable isotope mixing models. Alien species reach high biomass and can both survive to and accumulate high pollutants concentrations, potentially posing a risk for their predators and humans. A combined effect of environmental filtering and increased competition may potentially contribute to the disappearance of native species with lower tolerances.

Heavy metal concentrations and associated health risks in edible tissues of marine nekton from the outer Pearl River Estuary, South China Sea

Seven heavy metals including Hg, Cu, Pb, Cd, Zn, Cr, and As were examined in seventeen marine nekton species from the outer Pearl River Estuary (PRE), South China Sea. On the wet weight basis, the metal concentration ranges were 0.016-0.157 μg/g for Hg, 0.18-14.3 μg/g for Cu, 0.26-1.48 μg/g for Pb, 0.021-0.873 μg/g for Cd, 1.35-57.15 μg/g for Zn, 0.15-0.53 μg/g for Cr, and 0.42-7.83 μg/g for As, respectively. The levels of tested metals except for Pb in crustaceans were found to be higher than those in fish and cephalopods, suggesting that the diet and habitat played important roles on heavy metal accumulation ability of marine organism. Except for Cd in Champsodon capensis, Calappa lophos, and Portunus argentatus, all the left metal concentrations of investigated nekton species were below their permissible upper limits, indicating that consumption of examined marine nekton should be considered as safe for human health. The values of single target hazard quotient (THQ) and total THQ were all less than 1 and also suggested that there was no health risk for consumption. Even so, the local people should control their daily intake of crustacean foods from the outer PRE, since there might be potential As and Cd cumulative risks.

Evaluation of trace metals concentration and human health implication by indigenous edible fish species consumption from Meghna River in Bangladesh

This study is focused on the determination of trace metals (Cr, Cu, Zn, As, Pb, and Cd) concentrations of nine different indigenous fish species of Meghna River in Bangladesh to know the possible risk in human consumption. Fishes' wet muscles samples were analyzed to evaluate the level of trace metal concentrations. The concentrations (mg kg^-1 w/w) of the six selected trace metals were in the order Zn (1.42 ± 0.12) > Cr (1.31 ± 0.08) > Cu (0.92 ± 0.09) > Pb (0.54 ± 0.07) > Cd (0.51 ± 0.07) > As (0.47 ± 0.02). The results revealed that all the selected trace metals were below the maximum permissible limits recommended by the reference standards. The fish species may pose no risk with respect to the Estimated Daily Intake (EDI). Target hazard quotient (THQ) values for Cr, Cu, Zn, Pb, and Cd in all the fish species were <1.0, except for As which is dominantly organic in fishes. Both adults and children are vulnerable to carcinogenic health threat due to Cd exposure.

Accumulation of trace elements in selected fish and shellfish species from the largest natural carp fish breeding basin in Asia: a probabilistic human health risk implication

Intake of fish contaminated with non-essential hazardous trace elements poses a significant risk to human health. In this study, trace elements (As, Pb, Cd, Cu, Ni, and Zn) were measured in edible tissues of seven commercially important fish and shellfish species (Otolithoides pama, Pseudapocryptes elongatus, Macrobrachium rosenbergii, Liza parse, Notropis atherinoides, Apocryptes bato, and Rhinomugil corsula) from a natural carp breeding basin, Halda river, Bangladesh. The elements were detected by inductively coupled plasma-mass spectrometry (ICP-MS), and the hierarchy of elemental levels (mg/kg) was Zn (61.56) > Pb (30.45) > Ni (26.81) > Cu (21.09) > As (1.49) > Cd (0.24). Among the analyzed elements, Pb, Ni, and Zn for some fish species exceeded the permissible dietary limit, suggested by national and international agencies. In addition, results of bioaccumulation factor (BAF) indicated that most of the studied species were bioaccumulative in nature (BAFs > 1000), and the mean BAF of elements were found in the following order: Zn (3156.74) > Ni (1629.30) > Cu (1566.77) > As (997.14) > Pb (259.98) > Cd (216.52). However, the species, L. parse being omnivorous represented the highest BAF (stored higher concentrations of metals) as compared to other species. The growth pattern of all the species was negatively allometric, and the health condition of the species varied from poor to good state revealed from the estimated Fulton's condition factor (FC). For the evaluation of health hazards, estimated weekly (EWI), target hazard quotient (THQ), and carcinogenic risk (CR) were calculated for both adults and children. Results of EWI showed As, Pb, and Ni surpassed provisional tolerable weekly intake (PTWI)-recommended guidelines. The non-carcinogenic health effect (TTHQ) might not appear for both types of consumers (as TTHQ < 1), and CRs of all consumers were also in acceptable range (10^-6 to 10^-4). However, the probabilistic distribution through Monte Carlo simulation revealed that children were more vulnerable to non-carcinogenic (67.3%) and carcinogenic risk effect (47.3%) for Pb. Meanwhile, adults obtained the probability of 0.7% and 36% for THQ and CR effect, respectively, interpreting less vulnerable.

Bioaccumulation of Pyrethroid in Parasite Wenyonia acuminata (Cestoda: Caryophyllaeidae) and Host fish Synodontis clarias (Linnaeus, 1758) from Lekki Lagoon, Lagos Nigeria

This study was aimed at determining the concentration of pyrethroid in the surface water, sediment, Weyonia acuminata and Synodontis clarias fish in Lekki lagoon, Lagos, Nigeria. In-situ physicochemical analysis of the surface water was conducted using a calibrated handheld multi-parameter probe (Horiba Checker Model U-10). Intestinal samples from infected and uninfected fish were analyzed for pyrethroid concentrations, microbial colonization, proteins (PRO), superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malonaldehyde (MDA) and glutathione peroxidase (GPx). The histopathology of infected and uninfected intestinal tissues were analyzed using Haematoxylin and Eosin (H&E) stains and examined under a binocular light microscope (Model 230485). A total of 39 out of 98 S. clarias fish were infected with cestode parasite, Wenyonia acuminate, amounting to 39% parasite prevalence. Among the tested pyrethroids, Cyfluthrin and Alpha -cypermethrin had significant sorption of 1.62 and 3.27 respectively from the aqueous phase to the bottom sediment of the lagoon. Pyrethroid concentration was in the order of sediment > parasite> water > intestine> liver. The cholesterol, triglycerides, and LDL (low density lipids) in the parasite were higher than in the host fish (p<0.05). On the other hand, the fish hepatic protein, high density lipids (HDL) and glucose were higher than the levels in the parasites (p<0.05). There was a high prevalence of gut microbes (30 - 40%), which include Salmonella sp, Escherichia coli, Pseudomonas sp and Bacillus sp among individuals infected with gut Cestodes, Wenyonia sp compared with uninfected individual which had higher gut Staphylococcus sp., Klebsiella sp., and Proteus sp. (10- 40%). among the congeners of pyrethroids analyzed, Cyfluthrin > Alpha-Cyermethrin had significant sorption on the sediment, however unlike a benthopelagic fish, no pyrethroid was accumulated in the S. clarias from the sediment. The fish however accumulated Alpha-Cypermethrin from the aqueous phase. The parasite on the other hand accumulated Bathroid significantly from the surface water and bottom sediment which may be linked to the higher stress levels observed in the parasite than the host fish. The parasite in turn inflicted histological alterations on the host intestine, marked by moderate inflammation of mucosa, alteration of the villi microstructure, moderate stunting of the villous structure and moderate fibrosis of villous structure. The study demonstrated the efficiency of histopathological and microbial analysis in biomonitoring studies enteric parasites and early detection of pyrethroid toxicity respectively compared to bioaccumulation analysis.