Heavy metal bioaccumulation and risk assessment in fishery resources from the Gulf of Thailand

Bioaccumulation and Trophic Transfer of Heavy Metals in Marine Fish: Ecological and Ecosystem-Level Impacts

Heavy metal contamination in marine ecosystems poses a critical environmental challenge, with significant implications for biodiversity, trophic dynamics, and human health. Marine fish are key bioindicators of heavy metal pollution because of their role in food webs and their capacity for bioaccumulation and trophic transfer. This review synthesizes current knowledge on the pathways and mechanisms of heavy metal accumulation in marine fish, focusing on factors that influence the uptake, retention, and tissue distribution. We explore the processes governing trophic transfer and biomagnification, highlighting species-specific accumulation patterns and the risks posed to apex predators, including humans. Additionally, we assess the ecological consequences of heavy metal contamination at population, community, and ecosystem levels, emphasizing its effects on fish reproduction, community structure, and trophic interactions. By integrating recent findings, this review highlights key knowledge gaps and suggests future research directions to improve environmental monitoring and risk assessment. Given the persistence and bioavailability of heavy metals in marine environments, effective pollution control strategies and sustainable fisheries management are imperative to mitigate long-term ecological and public health risks.

Mercury trophic transfer and biomagnification in food webs within a tropical embayment as evidenced by nitrogen and carbon stable isotope analysis

Mercury (Hg) contamination in marine ecosystems poses a significant environmental threat due to its high toxicity, persistence in the environment, and tendency to bioaccumulate in organisms and biomagnify in food webs. Understanding how Hg moves through these food webs is essential for assessing its ecological and health impacts. To investigate the trophic dynamics of Hg in Rayong Bay, Gulf of Thailand, we collected marine organisms from the pelagic and benthic food webs during 2022-2023 and analyzed the total mercury content (THg) in plankton (phytoplankton, zooplankton, and fish larvae) and in 81 marine animal species. Furthermore, the stable nitrogen and carbon isotope values (δ15N and δ13C) were measured to establish their trophic levels (TLs) and potential food sources in the food web. Based on these analyses, we calculated the biomagnification factor using TL-adjusted ratios (BMFnorm) and trophic magnification factor (TMF) for the different TLs. BMFnorm values exceeded 1.0 in over 40 % of cases for both the pelagic and benthic food webs, indicating THg biomagnification from prey to predator. Notably, the pelagic food web exhibited a markedly higher TMF value (TMF = 6.68) compared to that of the benthic food web (TMF = 2.06), suggesting stronger Hg biomagnification within the pelagic food web. Our findings also highlight the consumption risk of Hg in some fish species in the Rayong Bay food webs, emphasizing the need for continued monitoring and mitigation strategies to safeguard both human and ecological health.

Elemental Composition and Health Risk Assessment of Deep-Sea Teleost's of the Levantine Basin

The determination of metal(loid) (As, Fe, Al, Sr, Zn, Pb, Mn, Cu, Cr, and Cd) levels in the muscle tissue of 23 different deep-sea bony fish sampled off Mersin Bay (NE Levantine Basin) and the assessment of health risks for human consumption were aimed. Tissue metal(loid) concentrations were determined as dry weight and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The tissue metal(loid) concentrations (µg g dw) were converted to wet weight prior to health risk assessment calculations. Standard mathematical formulas were used to determine the health risk assessment. There was a statistically significant difference between the fish species in terms of tissue metal(loid) levels (p < 0.05). The highest metal(loid) level was found in C. sloani among other species. As and Fe had the highest and Cd the lowest tissue concentrations in the examined species (p < 0.05). The relationships between the metal(loid)s analyzed in the tissue were significant (p < 0.01;0.05). Fe had an antagonistic effect with Cd, while other metal(loid)s had a synergetic effect with each other. Risk assessment analyses were performed for the consumable species, and it was found that the estimated daily and weekly intakes were below the tolerable limits established by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). The target hazard quotient (THQ) values exceeded the threshold of 1 (THQ > 1) only for As. The target cancer risk (TCR) was below the tolerable limits (> 10-5) except for As, Cd, and Al.

Heavy metals and arsenic in macrophytes, sediments and seawater from the coastal area of Northern and Central Vietnam

In the past decade, there has been a boost in the industry development in Vietnam, which is the cause of increased heavy metal release in the environment. The study presents the results of voltammetric analysis of heavy metals (Cu, Zn, Cd, Pb) and arsenic in water, sediments and 38 macrophyte species from the coastal area of Northern and Central Vietnam. The effects of sampling station location, depth, and algal divisions/species on elemental concentrations in the macrophytes were tested. Among the macrophyte species, the highest elemental concentrations were found in the red alga Laurencia sp. (As - 72 mg·kg-1) and brown algae Padina australis (Cd - 3.8 mg·kg-1), Spatoglossum vietnamense (Pb - 14.8 mg·kg-1), Dictyota dichotoma (Cu - 102 mg·kg-1), and Sargassum sp. (Zn - 32.5 mg·kg-1). The red and brown algae were the strongest trace element accumulators, while the green algae showed modest accumulation abilities. A significant decrease in the elemental concentrations in the seaweeds was observed with increasing depth, but As in the brown and red algae and Cd and Pb in the green algae were most accumulated at intermediate depths (5-8 m). The maximum arsenic and the minimum zinc concentrations in sediments were noted at the southern exit of the gulf. The bioaccumulation factors followed skewed, long-tailed distributions, with their maxima ranging from near zero (Cu) to several hundred (Cd). The study highlights spatial regularities of heavy metal accumulation and applicability of brown algal species as non-selective bioindicators of heavy metal pollution in the coastal area of Vietnam.

Heavy metal contamination in marine fish from the Andaman sea: Influence of habitat and health risk assessment

This study investigates Hg, Cd, Cu, Zn, and Pb concentrations in 324 fish samples from 43 species, including two cephalopod species, in the Andaman Sea. The fish were categorized into pelagic and demersal groups. The findings revealed average heavy metal concentrations in the order: Zn > Cu > Hg > Pb > Cd, with pelagic fish showing higher levels than demersal fish. Certain larger pelagic fish had mercury concentrations above prescribed limits, posing possible health hazards, even though they are less commonly consumed by humans. Cd and Pb levels in certain species exceeded regulatory thresholds of 0.05-1 μg/g and 0.3 μg/g, respectively, while Cu and Zn remained within safe limits. Although the overall cancer risk was low, the Target Hazard Quotient (THQ) and Hazard Index (HI) values surpassed 1, indicating significant health risks from consuming species such as Alopias superciliosus, Isurus oxyrinchus, Lepturacanthus savala, Makaira mazara, and Sphyraena barracuda. These findings underscore the need for ongoing monitoring and public advisories to mitigate health risks.

Human exposure to heavy metals and possible public health risks via consumption of mussels M. galloprovincialis from the Albanian sea cost

Heavy metals in the marine environment are significant contaminants that readily bioaccumulate in the tissues of aquatic organisms, particularly in filter-feeding animals such as bivalve molluscs. Human exposure to elevated concentrations of heavy metals, including essential elements such as Fe, Cu, and Zn, through the consumption of seafood can lead to various pathological effects. Research has demonstrated that among bivalve molluscs, mussels are the most effective indicators for monitoring marine pollution. Consequently, this study focused on the species Mytilus galloprovincialis to evaluate the levels of Al, As, Cd, Cr, Cu, Fe, Mg, Ni, Pb, and Zn in the two primary harvesting areas of Albania and to assess the associated human health risks from mussel consumption. The results revealed a concerning situation, particularly for Pb and Cd, with average concentrations of 2.15 μg/g and 4.14 μg/g, respectively, significantly exceeding the limits established by Regulation (EC) No. 915/2023. The levels of the other investigated elements also raised concerns, as only half of them were within the dietary intake values recommended by scientific authorities for weekly consumption of 250 g of mussels.

Assessment of potentially toxic element contamination in commercially harvested invertebrates from the Beibu Gulf, China

Marine pollutants, especially potentially toxic elements (PTEs), increasingly threaten the ecological environment and fishery resources of the Beibu Gulf due to their bioaccumulative nature, toxicity, and persistence. However, the occurrences of multiple PTEs in marine invertebrates within this region remains unclear. Hence, a total of 18 species of commercially harvested invertebrates (shrimp, crab, cephalopod, shellfish, and sea cucumber) were collected from the Beibu Gulf, and the concentrations of nine important PTEs (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) were examined. Subsequent stable isotope analysis for δ13C and δ15N facilitated investigations into biomagnification and human health risk assessment. The results showed that, except for As, the concentrations of the PTEs in the invertebrates were below the national safety limits. Furthermore, significant positive correlations were found between trophic levels (TLs) and log-transformed concentrations of As (P < 0.001, R2 = 0.20) and Cr (P < 0.001, R2 = 0.13), indicating biomagnification of these two metals across trophic positions among species. Finally, the human health risk assessment revealed that the consumption of cephalopod, shellfish, and sea cucumber poses a higher risk of adverse effects compared to shrimp and crab.

Ecological and health implications of heavy metal bioaccumulation in Thai Fauna: A systematic review

Heavy metals pose significant threats to ecosystems and human health due to their persistence and bioaccumulation. In Thailand, rapid industrialization, extensive agriculture, and urban development have exacerbated heavy metal pollution in both aquatic and terrestrial ecosystems. This systematic review, conducted according to PRISMA guidelines, evaluates study designs and methodologies to assess heavy metal bioaccumulation in Thai fauna, with a focus on ecological and health impacts. The review reveals that fish, particularly from families like Cyprinidae and Cichlidae, account for 42.11 % of studies, with species such as swamp eel, Henicorhynchus siamensis, Arius maculatus, Osteogeneiosus militaris, Puntioplites proctozystron, and Channa striata showing significant bioaccumulation. Molluscs (31.58 %), including Tegillarca granosa and Filopaludina martensi, serve as critical bioindicators of aquatic pollution due to their filter-feeding habits. Amphibians and crustaceans, like Fejervarya limnocharis and Fenneropenaeus merguiensis, also demonstrate vulnerability to heavy metal contamination. Key contamination hotspots include urban waterways in Bangkok, industrial discharges in Songkhla Lake, and mining sites in Loei Province, highlighting widespread environmental and health impacts. Despite extensive research, gaps remain, particularly concerning benthic scavengers and detritivores, which are vital for ecosystem functions. The review underscores the need for targeted monitoring and mitigation, including stricter regulations on industrial discharges, improved waste treatment, and better management of agricultural runoff. While metals like cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) are well-studied, further research on less-examined metals and species-specific bioaccumulation patterns is crucial to enhancing environmental management, supporting biodiversity conservation, and improving ecosystem resilience in Thailand.

Bioaccumulation dynamics, noncarcinogenic and carcinogenic risks of heavy metals in commercially valuable shellfish and finfish species from the world largest floating slum, Makoko, Nigeria

This study examined ten heavy metals in five species: Macrobrachium vollenhovenii, Penaeus monodon, P. notialis, Chloroscombrus chrysurus, and Pseudotolithus typus, from Makoko floating slum, Lagos Lagoon to discern their bioaccumulation potentials, sources of origin, and health implications. The concentrations were in this order: Fe (4.172-10.176) > Zn (1.310-5.754) > Mn (0.475-2.330) > Cu (0.238-1.735) > Pb (0.121-0.391) > Cd (0.055-0.283) > Co (0.056-0.144) > Ni (0.039-0.121) > Cr (0.022-0.095) > As (0.003-0.031) mg/kg. The MPDI denotes "low toxicity," and the BAF/BSAF revealed that benthic species had higher bioconcentration potentials. Multivariate analyses revealed that heavy metals exhibited mutual relationships during chemical transport, and their sources were both geogenic and human-induced. The HI values were below 1, and the TCR values were below the threshold of 1 × 10-4. This suggests that the probabilities of noncancer and carcinogenic risks in human populations due to long-term consumption of the evaluated species are unlikely.

Assessment of health risks associated with heavy metal contamination in selected fish and crustacean species from Temsah Lake, Suez Canal

Marine pollution caused by heavy metals has emerged as a significant environmental concern, garnering increased attention in recent years. The accumulation of heavy metals in the tissues of marine organisms poses substantial threats to both marine ecosystems and human populations that rely on seafood as a primary food source. Fish and crustaceans are effective biomonitors for assessing heavy metal contamination in aquatic environments. In this study, we determined the concentrations of several heavy metals, including cadmium (Cd), lead (Pb), nickel (Ni), mercury (Hg), and tin (Sn), in four fish species (Mugil cephalus, Mugil capito, L. aurata, and Morone labrax) and five crustacean species (S. rivulatus, Cerastoderma glaucum, Paratapes undulatus, R. decussatus, Callinectes sapidus, and Metapenaeus Stebbingi) from Temsah Lake during both winter and summer seasons. To evaluate the potential ecological and health risks associated with consuming these fish and crustacean species, we calculated the metal pollution index (MPI), weekly intake (EWI), target hazard quotient (THQ), and carcinogenic risk (CR) values. The results revealed a noticeable increase in metal levels during the summer compared to winter in the studied samples. Moreover, the concentration of heavy metals in the muscles of the species generally exceeded those in the liver and gills. The MPI values indicated that Morone labrax exhibited the highest values during winter, while L. aurata showed the highest values during summer. Mugil cephalus demonstrated the lowest MPI values in both seasons. The EWI values for the studied metals were found to be lower than the corresponding tolerable weekly intake (TWI) values. Additionally, under average exposure conditions, the THQ and HI data were generally below one for most study species in the area. The calculated CR values for investigated metals in the studied species indicated acceptable carcinogenic risk levels. Therefore, this suggests that consuming studied species within Temsah lake does not present any potential health hazards for consumers.

Exploring the macrominerals and heavy metals profile of deep-sea fishes: A pioneering study on trawl bycatch and discards in the Arabian Sea

This study assesses macrominerals (Na, K, Ca, Mg, P) and heavy metals (As, Cd, Cr, Cu, Ni, Pb, Se, Sn, Mn, Co, Fe, and Zn) content of deep-sea fish bycatch in the Arabian Sea, offering insights into their nutritional value, toxicant levels and health implications. Variations in Ca, K, P, Mg, and Na levels across species highlight mineral diversity. Setarches guentheri has the highest Ca (7716 mg/kg ww), K (2030.5 mg/kg ww), and P (13,180 mg/kg ww) concentrations. Dactyloptena orientalis exceeds the Cd limit (0.1284 mg/kg ww). Elevated Se levels in fishes were noted, with Dactyloptena orientalis (0.8607 mg/kg ww), Satyrichthys laticeps (0.7303 mg/kg ww), and Snyderina guentheri (0.6193 mg/kg ww). Fish like Pterygotrigla hemisticta contains high Zn (32 mg/kg ww), meeting Recommended Dietary Allowance limits. Deep-sea fish have safe heavy metal levels, but Cd, Se, and Zn exceed acceptable limits. It has been concluded that the consumption of fish species will not pose a potential health risk to humans.