Biological risk assessment of heavy metals in sediments and health risk assessment in bivalve mollusks from Kaozhouyang Bay, South China

Chemical speciation and health risk assessment of potentially toxic elements in playground soil of bell metal commercial town of Eastern India

Contaminated playground soils can expose players to harmful pollutants, increasing the risk of respiratory, skin, and gastrointestinal issues and potentially impacting long-term health and development. This study investigated the chemical forms and the human health risks associated with potentially toxic elements (PTEs) found in playground soil samples from Khagra, a historic town known for its bell metal industry, located in the Murshidabad district of eastern India. Sequential extraction techniques were employed to analyze the distribution of PTEs such as As, Cd, Co, Cu, Mn, Pb, Ni, Sn, and Zn among different fractions: exchangeable (F1), bound to carbonate phase (F2), bound to iron and manganese oxides (F3), bound to organic matter (F4), and residual (F5). The playground soil showed the highest contamination with Sn, with an IPOLL value of 3.14, indicating moderate to heavy contamination, while Cd, Cu, Mn, Pb, and Zn exhibit moderate contamination. The mean concentration of PTEs in all fractions (F1-F5) follows the order: Fe > Zn > Cu > Mn > Pb > Sn > Ni > Co > As > Cd. The maximum affinity of PTEs and their percentages are as follows: Fe (F5, 80.6%), As (F5, 55.31%), Cd (F5, 48.8), Co (F5, 64.9%), Mn (F3, 44%), Ni (F5, 53.2%), Pb (F3, 44.7%), Zn (F3, -43.19%), Sn (F3, 55%), Cu (F5 -42.18). As, Cd, Co, Cu, Fe, and Ni have a high affinity for F5, indicating geogenic source, while Mn, Pb, Sn, and Zn have a high affinity for F3, indicating anthropogenic source. Fe-Mn oxide partition was dominant for nearly all PTEs due to elevated sorption of cations onto Fe-Mn oxides at high pH. The risk assessment code for Cd, Cu, Mn, Ni, Sn, and Zn in playground soil is categorized under moderate risk, below 30%, while other elements showed no risk. Also, mobility factors were calculated for each PTEs, suggesting the degree of mobility that PTEs can easily migrate and be taken up, absorbed, or adsorbed by the human body. The mobility factor in playground soil was higher for Sn (59.89%) followed by Mn (54.24%) > Pb (52.91%) > Zn (52.01%) > Cd (39.49%) > Ni (33.20%) > As (30.39%) > Co (26.56%) > Cu (21.24%) > Fe (11.20%). Risk hazard quotients for children and adults were found to follow the order: Pb (0.263; 0.040), Cu (0.098; 0.015) > As(0.056; 0.008) > Mn (0.045; 0.009) > Zn(0.36; 0.05) > Cd(0.006; 0.001) > Ni (0.004; 0.001) > Co (0.001; 0.0). PTEs detected in the environment result from atmospheric deposition from small-scale metallurgical industries (bell metal and brass), coal and oil combustion, civil works, municipal waste incineration, and fugitive emissions from road dust. The human non-carcinogenic health risk for PTEs from ingestion and dermal contact was higher than that from inhalation. In the context of carcinogenic risk, As shows the highest health risk of 2.51E-05, followed by Cd (1.02E-09) and Co (8.14E-09). This study uniquely assesses the chemical speciation of PTEs in playground soils, revealing their geogenic and anthropogenic sources, and evaluates associated health risks. Policy intervention is vital for monitoring and remediating PTEs in playgrounds to protect children's health.

Contamination, fraction, and source apportionment of heavy metals in sediment of an industrialized urban river in China

In this study, we conducted an analysis of the heavy metal concentrations, health risk assessment, fraction and source interpretation in surface and core sediments from main stream of the Pearl River and Pearl River Estuary (RRE) area. Results showed that the higher deposited heavy metal concentrations in sediments occur at the Pearl River. The concentrations of heavy metals in surface sediments from the studied locations are in a descending order: Zn > Cr > Cu > Ni > Pb > Cd. Regarding chemical fractions, Cd showed the highest proportion of acid soluble fraction (F1) among all studied heavy metals. The high mobility of Cd poses a significant threat to water bodies and the surrounding environment. The potential ecological risk index (RI) showed the Pearl River sediments exhibited significantly higher values than the estuary sediments. Cd was found to be the primary contributor to potential ecological risk, accounting for 74% of RI. The health risk assessment showed the total hazard index (HI) for child was exceeded 1 mainly driven by Zn, indicating that the child population was at risk of non-carcinogenic effects. Besides, unacceptable carcinogenic risk in both Pearl River and estuary area were observed for children. The positive matrix factorization (PMF) model was used to ascertain sources of six heavy metals and apportion their contributions in sediments. The results showed that the source contributions of natural, industrial, and mixed sources from coal combustion and traffic emissions accounted for 39.81%, 34.10%, 26.10%.

Sasa argenteostriata - A potential plant for phytostabilization remediation of lead-zinc tailing-contaminated soil

Phytoremediation is an effective way to remediate metal-contaminated soils. During phytoremediation, plants immobilize heavy metals through the roots to reduce the mobility, toxicity and dispersal of the metals, and the changes in the activity of the roots are often accompanied by changes in the rhizosphere ecosystems, in which rhizobacteria are essential components and interact with roots to maintain the stability of the rhizosphere ecosystem and improve soil health. In this study, the phytoremediation potential of Sasa argenteostriata (Regel) E.G. Camu and the response of rhizobacteria were revealed with different levels of lead-zinc tailing contamination (Pb, Zn, and Cd concentrations of 1197.53, 3243.40, and 185.44 mg/kg for M1 and 2301.71, 6087.95, and 364.00 mg/kg for M2, respectively). The BCF of Sasa argenteostriata increased with increasing soil pollution, and the BCFPb, BCFZn, and BCFCd were 0.19, 0.27, and 0.08, respectively, under the M2 treatment; in contrast, the TF decreased with increasing soil pollution, and the TFPb, TFZn, and TFCd were 0.39, 0.85, and 0.07, respectively, under the M1 treatment. The mobility of Pb in the rhizosphere was higher than that of Zn and Cd, and the percentage of residual (Res) Zn and Cd in the rhizosphere increased, while the acid-soluble (Aci) Pb was significantly higher, leading to obvious uptake of Pb by the roots. Correlation analysis showed that Sasa argenteostriata affected the rhizobacterial community by changing the rhizosphere soil pH, the contents of organic matter and NRFM, and bacteria such as Proteobacteria and MND1, which are highly resistant to heavy metals (HMs), became the dominant species in the community. Further PICRUSt2 analysis showed that reducing metal transport across the membranes and increasing the efficiency of cellular reproduction were the main metabolic mechanisms of bacterial tolerance to HMs. Overall, the roots of Sasa argenteostriata were able to immobilize more heavy metals in PbZn tailing-contaminated soil, reducing the toxicity of HMs in the soil, and then influencing the rhizobacteria to change the community structure and metabolism mechanism to adapt to the HM-contaminated environment, and the soil fertility was increased, which together promoted the health and stability of the soil. This study is the first to illustrate the phytoremediation potential and response of the rhizobacterial community of Sasa argenteostriata under multimetal contamination of PbZn tailings. The results of the study provide some guidance for the practice of lead-zinc tailing-phytoremediation and soil health.

Consumption of Bivalve Shellfish in French Coastal Populations: Data for Acute and Chronic Exposure Assessment

Shellfish are a source of nutrients but are also a matter of concern in terms of food safety due to natural contaminants such as phycotoxins or anthropogenic contaminants including microbial agents and heavy metals. However, data related to consumption for each mollusk species are scarce and missing for appropriate exposure calculation. The objective of the study was to generate shellfish consumption data in the adult coastal population in France to assess exposure to health risks, the effects of determinants on the frequency of consumption and usual intake, and shellfish food risk perception. Our study, named the CONSOMER study, was carried out using an online survey in 2016 and 2017 and included a food frequency questionnaire. After validation, 2,479 individual questionnaires were available for statistical analysis. Our findings provide estimates of shellfish consumption frequency, portion sizes, weekly intake in g/week, and g/week/body weight that can be used for acute and chronic exposure calculations. For the acute risk, the 97.5th percentile of the portion size was found to be around 290 g for the adult coastal population. For chronic exposure, recreational shellfish harvesting activities were associated with higher weekly intakes. A non-negligible part of this subpopulation is not aware of food safety recommendations concerning harvesting areas. Results for shellfish harvester consumption in particular are consistent with other available data. Exposure calculations and safety recommendations should target shellfish harvesters.

Metal(loid)s content in Concholepas concholepas (Mollusca) and human health assessment in a coastal environmental sacrifice zone, central Chile (∼32°S)

In seafood, the study of metal(loid)s is essential to assess their toxicity and to establish risks of human exposure. This study investigates the content of As, Cd, Cu, Ni and Pb in Concholepas concholepas in a coastal environmental sacrifice zone (Chile) to assess potential human-health risks by consumption of C. concholepas. The Cu and Cd content was found to be above the safety level established in chilean and international regulations. The Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) for As were comparatively high with respect to the other metals analysed. The THQ-As and Hazard Index (HI) suggest a moderate carcinogenic risk due to the consumption of C. concholepas in six of the nine sectors analysed. THQ and HI are reasonable indicators to assess risks to human-health from the consumption of shellfish with HMs. C. concholepas can be considered as a biomonitor to study metal(loid)s on the Chilean coast.

Heavy metals accumulation in bivalve mollusks collected from coastal areas of southeast China

The distribution of six heavy metal and metalloids (As, Cd, Cr, Hg, Ni and Pb) was analyzed in 597 bivalve mollusks (8 species) collected from coastal areas of southeast China. Target hazard quotient, total hazard index, and target cancer risk were calculated to evaluate potential human health risks from bivalve consumption. The mean concentrations of As, Cd, Cr, Hg, Ni and Pb were 1.83, 0.581, 0.111, 0.0117, 0.268 and 0.137 mg kg^-1 wet weight in bivalves. The average estimated daily intakes for As, Cd, Cr, Hg, Ni and Pb were 1.156, 0.367, 0.07, 0.007, 0.167 and 0.087 μg kg^-1 body weight/day. Health risk assessment showed that there was no non-carcinogenic health risk to general residents to these metals from consumption of bivalves. Cd intake through mollusks posed a potential cancer risk. Accordingly, regular monitoring for heavy metals, especially Cd is recommended with respect to potential contaminant on marine ecosystems.

Human health risk assessment of metals and arsenic via consumption of commercial bivalves in the Gulf of California, Mexico

Although various studies have reported the bioaccumulation of metals in bivalves of commercial interest from the Gulf of California (GC), the risk associated with their consumption remains poorly understood. In this study, our own and bibliographic concentrations of 14 elements in 16 species of bivalves from 23 locations were used to investigate (1) the species-specific and regional accumulation of metals and arsenic in bivalves, (2) the human health risks by age and sex, and (3) the maximum allowable consumption rates (CRlim). The assessments were done according to the US Environmental Protection Agency guidelines. The results indicate that the bioaccumulation of elements varies markedly between groups (oysters > mussels > clams) and localities (higher on Sinaloa due to intense anthropogenic activities). However, consuming bivalves from the GC remains safe for human health. To prevent health effects for residents or consumers on the GC, we recommend (1) following the CRlim proposed herein; (2) monitoring levels of Cd, Pb, and As (inorganic) in bivalves, as the elements of top concern, mainly when are consumed by children; (3) calculating CRlim for more species and locations, including at least: As, Al, Cd, Cu, Fe, Mn, Pb, and Zn; and (4) determine the regional consumption rates of bivalves.

Integrated biomarker responses and metal contamination survey in the wedge clam Donax trunculus from the Atlantic coast of Morocco

In Morocco, the marine environment has always been a major occupation for socioeconomic activities (industry, tourism, urbanization, etc.). Thus, this work displays a case study of Taghazout coast in the central Atlantic part of the country, which becomes the center of several development projects, such as the touristic resort Taghazout Bay. In the aim to assess the health status of this coastal ecosystem, a multi-indicator approach based on the response of biomarkers in the wedge clam Donax trunculus was adopted during two years (2016/2017). The undertaken investigations on the response of biomarkers (AChE, GST, MDA, and CAT) in the sentinel species D. trunculus showed an activation of defense mechanisms in this bivalve, which would imply exposure to chemical stress in this ecosystem. The monitoring of seasonal bioaccumulation of cadmium (Cd), lead (Pb), and copper (Cu) by D. trunculus indicates that the bivalves collected have been exposed to these metal sources in the study area. In addition, the correlation study has reported a significant effect of environmental parameters on biomarker response. Overall, the multi-indicator approach has clearly revealed the health status of Taghazout coast registered in a coastal urbanization.

Implications for the seafood industry, consumers and the environment arising from contamination of shellfish with pharmaceuticals, plastics and potentially toxic elements: A case study from Irish waters with a global orientation

Shellfish are a rich source of minerals, B-vitamins and omega-3 to the human diet. The global population is expected to reach 9.6 billion people by 2050 where there will be increased demand for shellfish and for sustained improvements in harvesting. The production of most consumed species of shellfish is sea-based and are thus susceptible to in situ environmental conditions and water quality. Population growth has contributed to expansion of urbanization and the generation of effluent and waste that reaches aquatic environments, potentially contaminating seafood by exposure to non-treated effluents or inappropriately discarded waste. Environmental contaminants as microplastics (MP), pharmaceuticals (PHAR) and potentially toxic contaminants (PTE) are being identified in all trophic levels and are a current threat to both shellfish and consumer safety. Immunotoxicity, genotoxicity, fertility reduction, mortality and bioaccumulation of PTE are representative examples of the variety of effects already established in contaminated shellfish. In humans, the consumption of contaminated shellfish can lead to neurological and developmental effects, reproductive and gastrointestinal disorders and in extreme cases, death. This timely review provides insights into the presence of MP, PHAR and PTE in shellfish, and estimate the daily intake and hazard quotient for consumption behaviours. Alternatives approaches for seafood depuration that encompass risk reduction are addressed, to reflect state of the art knowledge from a Republic of Ireland perspective. Review of best-published literature revealed that MP, PHAR and PTE contaminants were detected in commercialised species of shellfish, such as Crassostrea and Mytilus. The ability to accumulate these contaminants by shellfish due to feeding characteristics is attested by extensive in vitro studies. However, there is lack of knowledge surrounding the distribution of these contaminants in the aquatic environment their interactions with humans. Preventive approaches including risk assessment are necessary to safeguard the shellfish industry and the consumer.

Seasonal variations and human health risk assessment of trace elements in the bivalve ecosystem in the Sea of Marmara

Twelve trace elements were studied in four economically important bivalve molluscs (Mediterranean mussel, manila clam, striped venus clam, and truncated wedge clam) from the southern Marmara Sea for seasonal bioaccumulation and human health risk assessment. According to the findings, Fe and Zn were the most accumulative and element concentrations changed considerably (P < 0.05) between seasons and species. Daily, weekly, monthly intake and target hazard quotients of the trace elements were estimated and compared with maximum limits. The results revealed that consuming these bivalve molluscs from the southern Marmara Sea could be considered safe for human consumption. Nevertheless, further monitoring is needed in order to better follow the development in time of elemental pollution due to increasing environmental pressure on the Marmara Sea basin, together with research on other different bioaccumulative organisms.

Heavy metal(loid)s in multiple media within a mussel mariculture area of Shangchuan Island, China: Partition, transfer and health risks

Limited research has been conducted on the heavy metal (loid) (HM) exchanges among seawater, sediments and cultured mussels in mariculture areas. To determine the impacts of mussel mariculture on the transfer and risks of HMs in coastal environments, samples of seawater, sediments and cultured mussels from a typical mariculture area in the South China Sea were analysed. The logarithmic partition coefficients of sediment/water indicated that HMs were preferentially retained by sediments. There were relatively low ecological risks in mussel raft mariculture areas. Principal component analysis and correlation analysis revealed the influences of terrestrial input and ocean circulation on the HMs in seawater, and the bioaccumulation factors reflected the possible accumulation of HMs in seawater by cultured mussels. Mussel farming was the indirect source of HMs in sediments, and the biochemical processes of cultured mussels promoted the transfer and accumulation of HMs into sediments. Health risk assessment revealed that children were more susceptible than adults, and Cd, As and Cr were among the threatening elements. Nonetheless, the health risks that were possibly caused by the daily consumption of farmed mussels were still within safe limits. Thus, the potential pollution remediation and biomonitoring functions of mussel aquaculture in coastal water environments will be further studied in the future.

Identification of heavy metal pollution in estuarine sediments under long-term reclamation: Ecological toxicity, sources and implications for estuary management

Sediment samples were collected to clarify the effect of changing sedimentary environment under long-term reclamation on heavy metals (Cr, Zn, Pb, Cu, Cd, and Ni) in a partially mixed estuary (Modaomen) of the Pearl River Delta. The ecological toxicity and source apportionment of these metals were discussed as well. The metal species during the 2010s (as 2015, 2018) was more enriched than that during the 2000s (as 2003) and 1990s (as 1991). This estuary overall suffered from a "moderate-to-high" pollution status. The element Cd was a major concern for the ecosystem's health because of its high toxicity. Sediment quality guidelines suggested that adverse biological effects were likely to be caused by Cu and Cd in the early adjustment stage, while the threats to marine organisms caused by the elements of Cu, Cr, Zn, and Ni were elevated during the 2010s. Two receptor models of PCA-MLR and PMF quantified the source types and contributions of these heavy metals. Strong intensity of industrial activities coupling with agricultural applications and import of adjacent seas were responsible for the enriched accumulation of heavy metals in sediments. Metal source apportionment would help to control the metal input into the estuary; identifying the role of sedimentary environment on heavy metals can inform the sediment quality management in the estuary.

Effects of Human Activities on the Spatial Distribution, Ecological Risk and Sources of PTEs in Coastal Sediments

Potentially toxic elements (PTEs) have attracted substantial attention because of their widespread sources, long residue time and easy accumulation. PTEs in the surface sediments of inshore waters are strongly affected by human activities because these waters are a zone of interaction between the ocean and land. In the present study, to explore the environmental geochemical behaviour and source of PTEs in the surface sediments of coastal waters, the contents and spatial distributions of copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), mercury (Hg) and arsenic (As) in different regions of Xiamen Bay were investigated. The data were processed by multivariate statistical methods, and the distribution characteristics of PTEs in the surface sediments of Xiamen Bay were analysed. In addition, the pollution load index (PLI), geo-accumulation index (Igeo) and potential ecological index(RI) were used to evaluate the pollution degree and potential risk in the surface sediments of Xiamen Bay, and the positive matrix factorisation (PMF) model was used to analyse the source. The results show that Zn had the highest mean concentration, followed by Pb, Cr, Cu, As, Cd and Hg, among the seven PTEs. The mean contents of Pb, Zn, Cd, Cu and Hg, and especially Hg and Cd, were higher than the corresponding environmental background values. The average PLI value indicated that the Xiamen Bay sediment was moderately contaminated by PTEs. The Igeo results showed that Xiamen Bay was moderately to strongly polluted by Cd and Hg. The proportions of samples with low, medium and strong risk levels were 11.63%, 74.42%, and 13.95% in surface sediments, respectively. PMF models showed that the input of chemical fertilizer and medication, anthropogenic atmospheric components and terrestrial detritus were the main sources of PTEs in the surface sediment of Xiamen Bay.

Concentrations and health risks of heavy metals in five major marketed marine bivalves from three coastal cities in Guangxi, China

Seafood consumption provides essential elements to humans while also posing risks to human health. A total of 2610 individuals of five edible marine bivalve species (Ruditapes philippinarum, Paphia undulata, Meretrix meretrix, Sinonovacula constricta and Meretrix lyrata) were randomly sampled from six farmer markets in three cities (Beihai, Qinzhou and Fangchenggang) in the southernmost coastal region of China. The concentrations of heavy metals (Cu, Pb, Zn, Cd, Cr, Hg and As) were determined by inductively coupled plasma mass spectrometry (ICP-MS). The estimated daily intake (EDI), target hazard quotient (THQ), total hazard index (HI), and target cancer risk (TR) were calculated to evaluate potential human health risks from bivalve consumption. The mean concentrations of metals in the tissues of bivalves descended in the order Zn > Cu > As > Cd > Cr >Pb > Hg in descending order, and the concentrations varied substantially among the five bivalves. Heavy metal concentrations in edible tissues of most bivalve samples were below the safety limits set by national and international regulations, and there were significant correlations between certain metal concentrations. The EDI values for each metal in each bivalve were significantly lower than the corresponding PTDI (provisional tolerable daily intake) values. Health risk assessment showed that although there is no noncarcinogenic health risk for local residents exposed to individual or combined metals from these bivalves, there is a carcinogenic risk from Cd and Cr exposure. Thus, in the long term, monitoring and controlling bivalve consumption will be important. Although current accumulation levels of bivalves are safe, continued and excessive lifetime consumption over 70 years may pose a target cancer risk.

Metal bioavailability, toxicity, and ecological risk due to sediments of a lately rehabilitated lake (Mariut, Egypt)

Sediments from Lake Mariut, Egypt, after its rehabilitation, and its anoxic diverted polluted drains were subjected to five sequential steps to define different geochemical fractions of eight studied metals. Results cleared out that 30-50% of its total Cd and total Co contents are easily bioavailable with a high-risk assessment code (RAC) to enter the food chain in the lake basin. Whereas Cu and Fe are safe and the remaining studied metals, i.e., Mn, Zn, Pb, and Cr are of medium risk for the environment. Individual contamination factor (ICF) is high (> 6) for all the studied metals except for Fe and Cu which are tightly held in sediments confirming their safeness to biota. Cadmium accounted for > 94% of the total risk in the study area. Metal pollution loading (MPL) from the sediments was found in the order: Fe > Mn > Zn > Pb > Cu > Cr > Co > Cd.

Source and risk assessment of heavy metals and microplastics in bivalves and coastal sediments of the Northern Persian Gulf, Hormogzan Province

The objectives of the current study are to investigate the concentration, biological risks, chemical speciation, and mobility of of heavy metals and also the determination of their distribution, physicochemical characteristics, and abundance of microplastics in coastal sediments and edible bivalves in the Persian Gulf, the coastal area of Hormozgan Province. Sampling points were selected considering the location of industrial, urban and Hara forest protected areas. In November 2017, a total of 18 sediment samples from coastal sediments (top 0-10 cm) and the most consumed bivalve species in the region were collected from two stations, Lengeh and Bandar Abbas Ports. The average concentration of heavy metals (except for Ni and Cd) in the sediments were lower than their average shale and the upper continental crust. Enrichment factors revealed significant enrichment of Ni, Mn, Cr, Cd and As. The fractionation of heavy metals using the Community Bureau of Reference (BCR) sequential extraction scheme indicated the high bioavailability of Zn, As, Mn, and Co. In general, the highest concentration of Mo, Cd, Pb, Zn, Cr, Cu, Mn, Hg, and Sb was detected in areas with frequent human activities including Shahid Rajaee Port, Shahid Bahonar Port, and Tavanir station. Shahid Rajaee and Shahid Bahonar Ports are the most important ports on the coast of Hormozgan province. The Risk Assessment Code calculated for the study elements indicates that As, Co, Zn, and Cu pose a moderate environmental risk a threat to the aquatic biota. Health risks of most heavy metals arising from bivalves consumption were safe, except for As which is associated with the high target cancer risk values. With reference to the type of microplastics found, they were mainly fibeours with lengths ranging between 100 and 250 μm in sediments and bivalves. Most of the microfibers found in the sediments were made of polyethylene terephthalate (PET) and polypropylene (PP), and the fibers found in the bivalves were made of PP.

A new method for estimating sedimental integrated toxicity of heavy metal mixtures to aquatic biota: a case study

The existing methods of measuring combined toxicity of heavy metal mixtures in environment do not fully consider three major factors (i.e., number of heavy metal species, aquatic biota, all investigated sites as an entity). Herein, a new method named joint probabilistic risk (JPR) method is proposed for evaluating the combined toxicity of heavy metal mixtures to aquatic biota. In this new method, the above three factors are fully taken into account. In order to evaluate the feasibility of the new method, the Pearl River Estuary (PRE) is selected as a case study. Concentrations of heavy metals (Cd, Pb, Cr, Ni, Cu, and Zn) in surface sediments of PRE are investigated and toxic equivalent factors (TEFs) of these heavy metals are calculated. Based on TEFs, sedimental concentrations of heavy metals of PRE are converted to Cd toxic equivalent concentration (Cd_eq), while the Cd toxicity data (Cd_to) are extracted from the literature. The probability density curves for Cd_eq and Cd_to are constructed and the overlap area is quantified as 0.2497. This indicates that the surface sediments of PRE have a 24.97% probability of toxic effect towards aquatic biota. Finally, this new method is validated by two indirect methods of mERMq and mPELq.

Human Health Risk Assessments of Trace Metals on the Clam Corbicula javanica in a Tropical River in Peninsular Malaysia

This study aimed to analyse ten trace metal concentrations in the edible part of the freshwater clam Corbicula javanica and to provide a critical assessment of the potential risks to human health through consumption of this clam as food based on well-established indices and food safety guidelines. The clams were captured from a pristine original site and transplanted to other sites with different environmental qualities. The trace metal levels in the edible total soft tissue (TST) of the clam were below those of the food safety guidelines referred to except for Pb, which exceeded the permissible limit set by the European Commission (2006) and the US Food and Drug Administration/ Center for Food Safety and Applied Nutrition); Interstate Shellfish Sanitation Conference. (USFDA/CFSAN; ISSC) (2007). The estimated daily intake (EDI) values of the clam were found to be lower than the oral reference dose and the calculated target hazard quotient (THQ) and total THQ were found to be less than 1. Therefore, in conclusion, the human health risk for consumption of TST of C. javanica at both average and high-level were insignificant regardless of the environment it was exposed to.

Biological Risk Assessment of Heavy Metals in Sediments and Health Risk Assessment in Marine Organisms from Daya Bay, China

The concentrations of heavy metals in sediments and marine organisms in Daya Bay were investigated, and the Monte Carlo method was used to analyze the uncertainty of the results of geo-accumulation characteristics and ecological and health risks. The mean concentrations of metal elements in sediments were in the following order: Zn > Cr > Cu > As > Cd > Hg, while those in marine organisms were Zn > Cu > As > Cr ≈ Cd > Hg. The geo-accumulation index (Igeo) indicated that the primary pollutant was Hg, with 5.46% moderately polluted, and 39.52% for unpolluted to moderately polluted. Potential ecological risks (RI) were between low and high risks, and the contributions of Hg, Cd, and As to ecological risks were 50.85%, 33.92%, and 11.47%, respectively. The total hazard coefficients (THQ) were less than 1, but on the basis of total carcinogenic risks (TCR), the probability of children and adults exceeded the unacceptable risk threshold of 22.27% and 11.19%, respectively. Sensitivity analysis results showed that the concentrations of carcinogenic elements contributed to risk in the order of As > Cd > Cr. Therefore, in order to effectively control heavy metals contamination in Daya Bay, it is necessary to strengthen the management of Hg, Cd, and As emissions.

Innovative health risk assessments of heavy metals based on bioaccessibility due to the consumption of traditional animal medicines

Few studies reported the extent of heavy metal accumulation in traditional Chinese medicines (TCMs). Currently, oral bioaccessibility of lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), and copper (Cu) present in traditional animal medicines was investigated with physiologically based extraction test-extracted in vitro model. We are the first to develop a health risk assessment strategy by combinational analysis of bioaccessible heavy metal levels to calculate target hazard quotient (THQ), target hazard index (THI) and cancer risk (CR), which has capacity to evaluate the heavy metal associated heath risk of traditional animal medicines. To precisely acquire a realistic risk assessment, questionnaire data was adopted to measure the frequency and duration of the exposure to traditional animal medicines, and the safety factor was highlighted as well. Our data revealed that the bioaccessibility of Hg was the lowest among the five heavy metals. After the adjustment with the bioaccessibility of each heavy metal to target hazard index (THI) values, excitingly, the results manifested that the consumption of traditional animal medicines might not exert an unacceptable health risk in a broad community. In addition, the CR values of As and Pb indicated that the risk of developing cancers was quite lower than their acceptable levels in the clinic.

Human Health Risk Assessment of Trace Metals in the Commonly Consumed Fish Species in Nakuru Town, Kenya

The present study was conducted to determine daily intake of cadmium (Cd), copper (Cu), and lead (Pb) and to assess noncarcinogenic human health risk caused by these trace metals in the commonly consumed fish species (Oreochromis niloticus, Rastrineobola argentea, Lates niloticus, and Protopterus aethiopicus) in Nakuru town, Kenya. Trace metal determination in the composite samples of the commonly consumed fish species was done using flame atomic absorption spectrophotometer. Cd, Cu, and Pb content in the muscle tissues of the commonly consumed fish species ranged from 0.11 ± 0.045 to 1.11 ± 0.931 mg kg-1 for Cd, 0.48 ± 0.013 to 3.00 ± 0.009 mg kg-1 for Cu, and 3.42 ± 0.045 to 12.78 ± 0.108 mg kg-1 for Pb. Cu concentrations were within Food and Agriculture Organization (FAO) recommended limits for this trace metal in fish. In contrast, Cd and Pb had values above their respective permissible limits in fish. The assessment of human exposure to trace metals indicated that exposure doses of Cd and Cu were safe for fish consumers. Conversely, target hazard quotient (THQ) values of Pb suggested possible health risks for consumers of the commonly consumed fish species in Nakuru town, Kenya.

Environmental risks associated with trace elements in sediments from Cartagena Bay, an industrialized site at the Caribbean

Cartagena Bay (CB) is an industrialized site in the Caribbean. The aim of this study was to evaluate contamination patterns by trace elements in sediments from CB. Sediment samples from twelve sites in CB, and three at the Grand Marsh of Santa Marta (GMSM), a reference site, were collected during dry and rainy seasons. Forty-four trace elements were evaluated employing ICP-MS, and mercury (Hg) was measured using a Hg analyzer. Most contaminated sites corresponded to stations related to repair and maintenance of ships, with high concentrations of Cr, Cu, As and Cd; as well as in areas where cargo transshipment centers and cruise ship terminals operate, which showed elevated levels of Ba. Stations receiving inputs from petrochemical and fertilizer plants displayed high content of Pb. At the station where an extinct chlor-alkali plant was located, a high total Hg level was found, highlighting its persistence. At least 70% of the samples presented Cr, Cu, and As concentrations that were ≥ Threshold Effect Level, < Probable Effect Level, ≥ Effects Range Low and < Effects Range Medium, suggesting adverse biological effects could occur occasionally. Potential Ecological risk values revealed that only Hg and Cd may generate deleterious effects to the aquatic life. However, with few exceptions, sediment samples from CB can be considered as moderately to heavily contaminated, as shown by the I_geo. In short, the principles of ecosystem-based management should be implemented along Cartagena Bay to guarantee safe levels of trace elements in sediments and a better quality of this estuary.

Bioaccumulation and health risk assessment of heavy metals to bivalve species in Daya Bay (South China Sea): Consumption advisory

Bivalves are one of the key components of the biogeochemical cycle in the marine system, and respond to heavy metal (HM) sensitively as filter feeders. To determine relationship of HMs in edible bivalve and seawater and HM effects on human health when digesting bivalves, HMs were analyzed in bivalves and seawater. The results showed that the mean HM concentrations in bivalves decreased in the order of Zn > Cu > Cr > Pb > As > Cd > Hg. Generally, all the bioconcentration factor values of bivalves were higher than 100, suggesting that bivalves have a high bioaccumulation ability. Nonmetric multidimensional scaling analysis indicated that all bivalves have a high bioaccumulation capacity for Cu and Zn. It was found that there are health risks associated with consuming bivalves, and children are more vulnerable than adults. Finally, the maximum allowable consumption rates of non-carcinogenic and carcinogenic risk were determined. These results provide the underlying insights needed to guide the consumption of seafood.

Appraisal of heavy metal contents in groundwater and associated health hazards posed to human population of Ropar wetland, Punjab, India and its environs

Heavy metals are well recognised for their toxicity and pose human health risks even at very low levels. In the present work, groundwater from Ropar wetland, Punjab, India and its environs (18 sites), were analysed for physico-chemical parameters, water quality indices, heavy metal contents (cadmium, cobalt, chromium, copper, lead and zinc) and possible health risks posed to adults and children during summer and winter seasons. Groundwater was slightly-alkaline, non-saline and hard which may be suitable for irrigation purposes. Among 18 samples, 7 and 9 samples in summer; 8 and 18 samples in winter exceeded BIS acceptable limits (mg L^-1) of 0.003 and 0.05 for cadmium and chromium, respectively. Mean non-cancer hazard quotients for cobalt (5.09-7.63) were >1. Mean hazard indices for cumulative risks posed by all heavy metals (6.00-10.11) were also >1. These results indicated higher risk of non-cancerous health problems in residents of the study area. Chromium was found to pose significant possible cancer risk (1.20-2.99 cases/1000 persons). Children were more prone to health problems than adults due to their lower body weight with greater risk in winters, which may be attributed to higher contamination of heavy metals in groundwater after leaching during monsoons. The results of water quality analysis and risk assessment indicated that the groundwater suffered from significant contamination and if used for long-term without pre-treatment, may pose serious health risks to human population via drinking water and irrigation of agricultural fields due to bioconcentration of heavy metals in food crops cultivated in those fields.

Heavy metal concentrations in commercial marine organisms from Xiangshan Bay, China, and the potential health risks

Commercial marine organisms were collected from the coast of Xiangshan Bay to investigate the concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and evaluate the potential health risks. The results indicated considerable variations in the heavy metal concentrations among six species groups, of them mollusks (seasnail, benthic bivalve, and oyster) generally contained relative high levels of most metals, followed by crustaceans (crab and shrimp), by contrast, fish had low concentrations of all metals, except Hg. Three heavy metal groups were identified to interpret the accumulative characteristics in the marine organisms. Spatial distributions illustrated the geographical variations of heavy metal concentrations in the sampling areas. Moreover, maricultured organisms demonstrated lower heavy metal concentrations than did the wild. Health risks of most heavy metals exposed from marine organism consumption were safe, except for As which is associated with the high target cancer risk values.

Contamination Evaluation and Source Identification of Heavy Metals in the Sediments from the Lishui River Watershed, Southern China

Seven heavy metals (Cr, Mn, Co, Ni, Cu, Zn, Pb) were measured in surface sediments from the Lishui River watershed, an area with increased soil erosion in China. The mean concentrations of heavy metals were 61.20 mg/kg (Cr), 757.15 mg/kg (Mn), 9.39 mg/kg (Co), 25.31 mg/kg (Ni), 22.84 mg/kg (Cu), 91.66 mg/kg (Zn), and 40.19 mg/kg (Pb), respectively. The spatial distribution of heavy metals was site-specific, exhibiting a remarkably high level in the sampling stations with intense agricultural activities (Lixian) and industrial activities (Jinshi). Contamination indexes including contamination factor, pollution load index, nemerow multi-factor index, potential ecological risk index, and human health risk were used to assess the pollution degree of the river sediments. The results indicated the pollution degree of heavy metals decreased in the order of Mn > Pb > Zn > Cr > Cu > Ni > Co. Heavy metals resulted in non-pollution to moderate pollution, with low ecological risk and an acceptable carcinogenic risk caused by Cr and Ni for children and adults. Person’s correlation analysis and principal component analysis, coupled with cluster analysis, revealed that the sediments from the Lishui River were mainly influenced by two sources. Cr, Co, Ni, and Cu were mainly derived from natural sources, while Mn, Zn, and Pb originated from agricultural and industrial activities, mining, and vehicular traffic.

Bioaccessibility and human health implications of heavy metals in different trophic level marine organisms: A case study of the South China Sea

This study investigated the total concentrations and bioaccessibility of heavy metals in edible tissues and trophic levels of 12 marine organism species in the South China Sea. The results were used to estimate health risks to humans. Of the heavy metals detected, nickel (Ni) was present at the highest concentrations, followed in descending, order by iron (Fe), zinc (Zn), manganese (Mn), chromium (Cr), copper (Cu), cadmium (Cd) and lead (Pb). Cd had the highest percentage bioaccessibility (61.91%). There were no correlations between log-transformed total metal concentrations and trophic level values, nor between log-transformed bioaccessibility metal concentrations and trophic level values. This indicates there is no biomagnification among these trace metals. The carcinogenic risk probabilities for Pb and Cr to urban and rural residents were below the acceptable level (< 1 × 10^-4). The target hazard quotient (THQ) value for each metal and the total THQ values for all metals studied indicated no significant risk of non-carcinogenic effects to urban and rural residents from consuming marine organisms from the South China Sea.

Heavy Metal Bioaccumulation in Rice from a High Geological Background Area in Guizhou Province, China

Long-term exposure to high levels of heavy metals can lead to a variety of diseases. In recent years, researchers have paid more attention to mining and smelting areas, industrial areas, and so forth, but they have neglected to report on high geological background areas where heavy metal levels are higher than China's soil environmental quality standard (GB 15618-2018). In our study, an investigation of heavy metals in paddy soil and rice in the high background area of Guizhou Province was carried out, and the factors affecting the absorption and utilization of heavy metals in rice were discussed. A total of 52 paddy soil and rice samples throughout the high geological background of Guizhou, China, were collected, and concentration(s) of arsenic, cadmium, copper, lead, and zinc were analyzed. The arithmetic mean values of paddy soil heavy metals were 19.7 ± 17.1, 0.577 ± 0.690, 40.5 ± 32.8, 35.5 ± 32.0, and 135 ± 128 mg kg-1 for arsenic, cadmium, copper, lead, and zinc, respectively. Most of the heavy metals' contents in the soil were above the soil standard value. The highest content of cadmium was 15.5 times that of the soil standard value. The concentration(s) of arsenic, cadmium, copper, lead, and zinc in rice were 0.09 ± 0.03, 0.01 ± 0.01, 1.57 ± 0.69, 0.002 ± 0.003, and 11.56 ± 2.61 mg kg-1, respectively, which are all lower than those specified by Chinese food safety standards (GB 2762-2017). The results and discussion show that the bioavailability, pH, and soil organic matter are important factors that affect the absorption of heavy metals by rice. According to the consumption of rice in Guizhou Province, the risk of eating rice was considered. The results revealed that the hazard quotient is ranked in the order of copper > zinc > cadmium > arsenic > lead, and there is little risk of eating rice in the high geological background area of Guizhou Province. These findings provide impetus for the revision and improvement of this Chinese soil environmental quality standard.