Health risk assessment of heavy metals in freshwater fish in the central and eastern North China

Toxic heavy metals in a landfill environment (Vientiane, Laos): Fish species and associated health risk assessment

Leachates from municipal landfills introduce toxic heavy metals into water, causing bioaccumulation. This study assesses metal levels and potential human health risks associated with consuming Anabas testudineus and Channa striata. Inductively coupled plasma mass spectrometry detected Cd, Cu, Cr, Ni, Pb, and Zn in both fish species. Leachate metal concentrations meet international discharge standards, Cd, Cr, and Pb in the fish exceed the international accepted values. Gastrointestinal tract+liver samples show significant variation between species, particularly in Cd and Pb. EDI, THQ/HI, and TR for the both species fall below TDIs, lower than the limit of 1, and within the acceptable range of the US-EPA permissible limit, respectively. Fish consumption appears safe regarding carcinogenic risk, but exceeding metal limits could impact heavy metals accumulation in the local food chain. Raising public awareness is crucial, and governmental agencies and environmental organizations should enhance waste treatment technologies and enact relevant health legislation.

Biochemical changes and bioaccumulation of manganese in Astyanax lacustris (Teleostei: Characidae)

Major tailings dam failures have occurred recently around the world and resulted in severe environmental impacts, such as metal contamination. Manganese is a metal highly associated with mining activities, largely detected in mining dam collapses. This metal is considered necessary for different organisms, but it can be toxic and cause oxidative stress and genetic damage in fishes. In this study, we investigated the toxic effects of manganese on Astyanax lacustris, by exposing the fish individually to different concentrations of this metal (2.11, 5.00, and 10.43 mg/L) for 96 h. To assess the effects of manganese, we used biochemical biomarkers (glutathione S-transferase, catalase, and acetylcholinesterase enzyme activity) and the manganese bioaccumulation in different tissues (liver and gills). The obtained data showed that only at concentrations of 5.00 mg/L and 10.43 mg/L the activity of glutathione S-transferase differed significantly. Additionally, the acetylcholinesterase activity in the brain tissue was inhibited. The highest level of manganese bioaccumulation was observed in the liver and branchial tissue. Overall, we concluded that high concentrations of manganese may cause physiological changes in Astyanax lacustris.

Metal Toxicity: Effects on Energy Metabolism in Fish

Metals are dispersed in natural environments, particularly in the aquatic environment, and accumulate, causing adverse effects on aquatic life. Moreover, chronic polymetallic water pollution is a common problem, and the biological effects of exposure to complex mixtures of metals are the most difficult to interpret. In this review, metal toxicity is examined with a focus on its impact on energy metabolism. Mechanisms regulating adenosine triphosphate (ATP) production and reactive oxygen species (ROS) emission are considered in their dual roles in the development of cytotoxicity and cytoprotection, and mitochondria may become target organelles of metal toxicity when the transmembrane potential is reduced below its phosphorylation level. One of the main consequences of metal toxicity is additional energy costs, and the metabolic load can lead to the disruption of oxidative metabolism and enhanced anaerobiosis.

Effects of Ca2+ and Mg2+ on Cu binding in hydrophilic and hydrophobic dissolved organic matter fractions extracted from agricultural soil

Dissolved organic matter (DOM) has significant effects on soil copper (Cu) bioavailability. However, little is known about Cu interactions and major cation binding toward hydrophilic and hydrophobic DOM components extracted from soil solutions. In this study, we investigated the influence of major cations (Ca2+/Mg2+) on Cu complexing characteristics on different hydrophilic and hydrophobic DOM fractions using absorbance spectroscopy at different Cu2+ concentrations in the absence/presence of Ca2+/Mg2+. Different compositional hydrophobic and hydrophilic DOM fraction proportions occurred at three agricultural soil sites, with the hydrophobic acid (HOA) fraction accounting for the highest proportion. The addition of Cu2+ generated distinct ultraviolet (UV) bands/peaks (processed by differential linear and differential logarithmic transformation) of three hydrophilic DOM fractions, whereas Cu2+ induced less and weak specific peaks in the differential spectra and differential logarithmic of the HOA fractions, indicating hydrophilic DOM fractions tend to have a higher density of Cu2+ complexation sites. In the presence of either Ca2+/Mg2+, increased depression caused by Cu2+ binding on different DOM fractions was observed with increasing 10, 100, and 1000 μM Ca2+/Mg2+ levels, with more significant variations in peaks/banks for hydrophilic base (HIB) and HOA fractions, and less for hydrophilic acid (HIA) and hydrophilic neutral (HIN) fractions. In our study, the spectral parameters ΔS225-275 and ΔS275-325 were successfully used to quantify Cu amounts bonded to HIA and HIB, respectively. They exhibited strong linear relationships with correlation coefficients (R2) of 0.96 for HIA and 0.87 for HIB, respectively. Furthermore, Mg2+ exhibited stronger competition with Cu for HIA and HIB binding sites when compared with Ca2+.

Review of the Terminology, Approaches, and Formulations Used in the Guidelines on Quantitative Risk Assessment of Chemical Hazards in Food

This paper reviews the published terminology, mathematical models, and the possible approaches used to characterise the risk of foodborne chemical hazards, particularly pesticides, metals, mycotoxins, acrylamide, and polycyclic aromatic hydrocarbons (PAHs). The results confirmed the wide variability of the nomenclature used, e.g., 28 different ways of referencing exposure, 13 of cancer risk, or 9 of slope factor. On the other hand, a total of 16 equations were identified to formulate all the risk characterisation parameters of interest. Therefore, the present study proposes a terminology and formulation for some risk characterisation parameters based on the guidelines of international organisations and the literature review. The mathematical model used for non-genotoxic hazards is a ratio in all cases. However, the authors used the probability of cancer or different ratios, such as the margin of exposure (MOE) for genotoxic hazards. For each effect studied per hazard, the non-genotoxic effect was mostly studied in pesticides (79.73%), the genotoxic effect was mostly studied in PAHs (71.15%), and both effects were mainly studied in metals (59.4%). The authors of the works reviewed generally opted for a deterministic approach, although most of those who assessed the risk for mycotoxins or the ratio and risk for acrylamide used the probabilistic approach.

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.

Occurrence, distribution, source apportionment, ecological and health risk assessment of heavy metals in water, sediment, fish and prawn from Ojo River in Lagos, Nigeria

The study investigates the occurrence and bioaccumulation of heavy metals in water, sediment, fish, and prawn from the Ojo River with a view to identify the source of origin and the associated ecological and human health risks. The result shows that heavy metal concentrations in water [As = 0.010, Cd = 0.001, Cr = 0.041, Cu = 0.019, Co = 0.050, Fe = 0.099, Pb = 0.006, Ni = 0.003, and Zn = 0.452(mg/L)] were within the acceptable limits. The heavy metals in the sediment [As = 0.050, Cd = 0.287, Cr = 0.509, Cu = 0.207, Co = 0.086, Fe = 33.093, Pb = 0.548, Ni = 0.153 and Zn = 4.249 (mg/kg)] were within their respective background levels or earth's crust and the TEL and PEL standard limits. The bioaccumulation of heavy metals in fish and prawn tissues are in this hierarchical form: Fe > Zn > Cu > Cr > Ni > Co > Pb > Ar > Cd and Fe > Zn > Cu > Cr > Pb > Ar > Ni > Co > Cd, respectively. The bioaccumulation factors of heavy metals in fish ranged from 0.893 - 16.611 and 1.056 - 49.204 in prawn, which were higher than the biota-sedimentation factors (BSAF) values, inferring that the fish and prawns of this study ingested heavy metals highly from water column. The aggregated BSAF scores (fish = 5.584 and prawn = 9.137) showed that these organisms are good concentrators of heavy metals in sediments. The water quality index and other pollution indices (Single pollution index, Heavy metal assessment index, and Heavy metal pollution index) demonstrates slightly clean water, with a moderate level of contamination. The HI values of heavy metals in water, fish, and prawn were lower than 1, implying non-carcinogenic risk in children or adults. The ADD and EDI values of the metals were within their respective oral reference doses (RfD). The TCR values showed that exposure to water, either by ingestion or dermal absorption and the consumption of P. obscura and M. vollenhovenii from the Ojo River would not induce cancer risks in people, though As, Cr, Cd, and Pb showed carcinogenic potentials. The sediment contamination indices such as CF, mCd, EF, and Igeo showed a moderate level of pollution. The ecological risk values (NMPI, mCd = 0.068, PLI = 0.016, and R.I = 86.651) of heavy metals implies "no-moderate risk" except for Cd, which showed high risk. The ecotoxicological parameters,  m-PEL-Q (0.024) and m-ERM-Q (0.016) denotes low contamination and no probability of acute toxicity. The CV analysis showed high dispersions and variabilities in the distributions of the heavy metals in water. Other source analyses (Pearson's correlation matrix, PCA, and HCA) showed that both natural processes and anthropogenic activities are responsible for the occurrence of heavy metals in water and sediment from the Ojo River.

Heavy metal concentrations in various tissues of two fish species from Damsa Dam Lake (Turkey) and associated health risk assessment

PURPOSE OF REVIEW AND METHOD

In this study, indicate the average or range of 10 heavy metal concentrations in muscle, gills and liver of two fish species (Squalius pursakensis and Cyprinus carpio) living in the Damsa Dam Lake (Turkey) was examined in relation to fish gender and size. Inductively coupled plasma-tandem mass spectrometry was used to evaluate the concentrations of heavy metals. The average contents of the metals in S. pursakensis muscle samples were 0.877, 9.285, 0.614, 0.488, 8.190, 0.155, 0.015, 0.010, 0.218, 0.009 mg/kg for Cu, Fe, Mn, Ni, Zn, As, Cd, Co, Cr and Pb respectively. On the other hand, the average contents of the metals in C. carpio muscle samples were 0.673, 8.001, 0.367, 0.435, 6.107, 0.188, 0.007, 0.007, 0.371, 0.012 mg/kg for Cu, Fe, Mn, Ni, Zn, As, Cd, Co, Cr and Pb respectively. In addition, human health risks were evaluated considering the estimated daily intake of heavy metals in adults. The target hazard quotient, hazard index and carcinogenic risk values were determined based on the frequency of fish consumption for the population living in the region.

RESULT AND CONCLUSION

The highest quantities of all heavy metals were determined in the gills and liver of the fish species. The levels of most heavy metals in tissues did not differ significantly between both fish species. Only a few heavy metals in the tissues of both fish species demonstrated significant associations with fish length or weight. In terms of the levels of most of the heavy metals in the tissues, there weren't any significant differences between the male and the female fish. The estimated daily intakes of all of the heavy metals were lower than the reference doses. The values of the target hazard quotient and the hazard index were found to be below 1 and the values regarding carcinogenic risk were assessed to be within or lower than the permissible levels. Cr, Cu, Zn, Cd, Pb and inorganic As values assessed in the muscle tissues of fish were found below the values acceptable by national and international institutions. These results proved that the examined fish species can be consumed safely.

Bioaccumulation and sources of metal(loid)s in fish species from a subtropical river in Bangladesh: a public health concern

Toxic metals and freshwater fish's metalloid contamination are significant environmental concerns for overall public health. However, the bioaccumulation and sources of metal(loids) in freshwater fishes from Bangladesh still remain unknown. Thus, the As, Pb, Cd, and Cr concentrations in various freshwater fish species from the Rupsha River basin were measured, including Tenualosa ilisha, Gudusia chapra, Otolithoides pama, Setipinna phasa, Mystus vittatus, Glossogobius giuris, and Pseudeutropius atherinoides. An atomic absorption spectrophotometer was used to determine metal concentrations. The mean concentrations of metal(loids) in the fish muscle (mg/kg) were found to be As (1.53) > Pb (1.25) > Cr (0.51) > Cd (0.39) in summer and As (1.72) > Pb (1.51) > Cr (0.65) > Cd (0.49) in winter. The analyzed fish species had considerably different metal(loid) concentrations with seasonal variation, and the distribution of the metals (loids) was consistent with the normal distribution. The demersal species, M. vittatus, displayed the highest bio-accumulative value over the summer. However, in both seasons, none of the species were bio-accumulative. According to multivariate statistical findings, the research area's potential sources of metal(loid) were anthropogenic activities linked to geogenic processes. Estimated daily intake, target hazard quotient (THQ), and carcinogenic risk (CR) were used to assess the influence of the risk on human health. The consumers' THQs values were < 1, indicating that there were no non-carcinogenic concerns for local consumers. Both categories of customers had CRs that fell below the permissible range of 1E - 6 to 1E - 4, meaning they were not at any increased risk of developing cancer. The children's group was more vulnerable to both carcinogenic and non-carcinogenic hazards. Therefore, the entry of metal(loids) must be regulated, and appropriate laws must be used by policymakers.

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

The muscle tissues of 19 fish species, two crab species, and one shrimp species collected from the Gulf of Thailand (GoT) were analyzed to determine the levels of heavy metals, including Cu, Zn, Fe, Mn, Ni, Pb, Cd, and Hg. The results revealed that the mean concentrations of the heavy metals, in descending order, were Zn > Cu > Fe > Cd > Hg > Mn > Pb > Ni. Among the examined metals, zinc was found to be the most prevalent in fish tissues. Based on the risk assessment indices, the estimated average daily doses (ADD) of the heavy metals were found to be below the provisional tolerable daily intake (PTDI) recommended by the joint Committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) on food contaminants. The results of the target cancer risk analysis revealed no related cancer risk from the consumption of the fishes considered for the study. However, the target hazard quotient (THQ) values exceeded the threshold of 1 (THQ > 1) specifically for mercury in Gymnothorax spp. and Terapon spp. Furthermore, the calculated hazard index (HI) values for fish muscles were all below 1, indicating that there is no significant health risk for humans at the current consumption rates, except in Terapon species for both normal and habitual consumers. Notably, habitual consumers of Gymnothorax species showed the highest HI value (>1), suggesting potential long-term effects on human health when consuming larger quantities of these fishes.

Trace metal exposure and risk assessment of local dominant fish species in the Beijiang River Basin of China: A 60 years' follow-up study

The Beijiang River, one of the Pearl River tributaries located in Guangdong, China, plays a critical role in providing water and fishery resources for the Pearl River Delta and receiving a large amount of domestic and industrial wastewater. However, due to the lack of historical monitoring data, we are unable to fully understand the relationship between the industrial and agricultural development and the environment. In this study, fish specimens collected from the Beijiang River Basin over a span of nearly 60 years (1963-2021) are used as research objects and the concentrations of ten trace metals (TMs) in two locally dominant fish species were determined by an inductively coupled plasma mass spectrometer. The human health risks caused by consuming fishes were assessed. Results show a correlation between the levels of TMs in fish muscle and the degree of industrialization. The concentrations of Cr, Mn, Ni, and Cu peaked during the period of 1981-1983, when China's industrial development was rapidly expanding while the environmental protection facilities were incomplete. However, with the implementation of Ecological Civilization policy, the levels of Cr, Mn, Ni, Cu, Cd, and Ba showed a downward trend in the period from 2018 to 2021. Cu concentrations in both fish muscle and viscera exhibit analogous change patterns across different periods, indicating that Cu serves as a significant indicator of TM pollution in the Beijiang River Basin. The presence of TMs in fish muscle often exhibits long-term enrichment, while those in the viscera demonstrate short-term accumulation. Based on the estimated daily intake, the target hazard quotient (THQ), and total THQ value, the overall health risk associated with TMs in fish from the Beijiang River Basin is low. However, certain TMs in the fish rebounded during 2018-2021, posing a potential risk for aquatic biology and ecosystems, which is worth our attention.

The presence of toxic heavy metals in tuna fishes from Laccadive sea and concomitant health risk

Concentrations of heavy metals in Yellowfin and Skipjack tuna fishes from the Laccadive sea were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) to evaluate the human health hazards via their consumption. The samples were collected from different atolls of Maldives to ensure a good representation of sample distribution. The metal concentration in tuna fish is found to be below the maximum tolerable limit set by different international organisations. The target hazard quotient values for individual metals were well below the limiting value of 1, indicating an insignificant health risk via the dietary intake of fish. The maximum targeted cancer risk value was 10 -4, indicating low carcinogenic risk from the consumption of tuna fish from the Maldives. Hence, the consumption of tuna from the Laccadive Sea is safe for human health.

Metals and Metalloid Concentrations in Fish, Its Spatial Distribution in PPC, Philippines and the Attributable Risks

Fish is an important source of protein in human meals around the world. However, the fish that we are eating may be contaminated with toxicants such as metals and metalloids (MMs), which may pose health risks to consumers. Information on MMs content in fishes and their potential spatial distribution scenarios would provide knowledge to the community to create strategies and protect human health. Hence, this study assessed and determined the health risk levels of MMs in both brackish and marine water fish (BMF) in Puerto Princesa City (PPC), Palawan Province, Philippines. PPC has an existing abandoned open mine pit near the PPC coastline called the "pit lake". The concentrations of As, Ba, Cu, Fe, Mn, Hg, and Zn in fishes were analyzed using portable Olympus Vanta X-ray Fluorescence (pXRF), and the spatial distribution of MMs concentrations in BMF was analyzed using a GIS (geographic information system). Fishes were sampled from fishing boat landing sites and nearby seafood markets. The results revealed that the concentration of MMs in marine fish was generally higher than the brackish water fish. It was recorded that the Hg concentration in marine water fish meat was higher than in brackish water fish meat. The Mn concentration in marine water fish exceeded the permissible limits set by international bodies. An elevated concentration of Mn in BMF was detected across the northern part of PPC, and an elevated concentration of Hg in marine fishes was recorded in the southeast area, where the fish landing sites are located. Ba was also detected in BMF across the southern part of PPC. Moreover, an elevated concentration of Cu was detected in MBF in the northeast and in marine fish in the southeastern area of PPC. Further, this paper elaborates the non-carcinogenic and carcinogenic risks of these fishes to the PPC population and tourists with respect to the MMs content in fish meat.

Assessing pathways of heavy metal accumulation in aquaculture shrimp and their introductions into the pond environment based on a dynamic model and mass balance principle

The impact of heavy metals (HMs) on the quality of aquaculture products has attracted worldwide attention. Since Litopenaeus vannamei is a popular aquaculture product among consumers worldwide, it is of great importance to guarantee its dietary safety. An in-situ monitoring program lasting for three months in a typical Litopenaeus vannamei farm found that Pb (100 %) and Cr (86 %) in the adult shrimp were higher than the safety guidelines. In the meantime, Cu (100 %), Cd (100 %) in the water and Cr (40 %) in the feed exceeded the corresponding thresholds. Therefore, quantification of different exposure pathways of shrimp and contamination origins in pond is valuable to improve the dietary safety of the shrimp. Based on Optimal Modeling for Ecotoxicological Applications (OMEGA), Cu was primarily from the ingestion of feed, accounting for 67 % of bioaccumulation, while Cd, Pb and Cr primarily entered shrimp through the adsorption from overlying water (53 % for Cd and 78 % for Pb) and porewater (66 % for Cr), respectively. The HMs in the pond water were further tracked based on a mass balance analysis. The main source of Cu in the aquaculture environment was feed, being responsible for 37 % of the total input. Pb, Cd and Cr were primarily from the inlet water with contributions of 84 %, 54 % and 52 %, respectively. In summary, the proportions of different exposure pathways and origins of HMs in pond-cultured shrimp and its living environment varied widely. To keep end-consumers eating healthily, species specific treatment is required. Feed should be regulated more for Cu. Aimed pretreatments for Pb and Cd in influent water are needed and an additional immobilization for Cr in sediment porewater should be investigated. After implementation of these treatments, the food quality improvement could be further quantified based on our prediction model.

Health risk assessment of dietary cadmium intake in children aged 2-17 years in East China

Food is the main way for people to be exposed to heavy metal cadmium (Cd), and Cd pollution will affect human health. In this paper, exposure and health risk assessment of dietary Cd intake were conducted in children aged 2, 3, 4, 5, 6-8, 9-11, 12-14 and 15-17 years in East China. The results showed that the total exposure of dietary Cd intake in children exceeded the standard limits. The total exposure of all age groups were 1.11 × 10-3, 1.15 × 10-3, 9.67 × 10-4, 8.75 × 10-4, 9.18 × 10-4, 7.75 × 10-4, 8.24 × 10-4, 7.11 × 10-4 mg kg-1 d-1, respectively, and the highest was the children aged 3 years. The hazard quotients of children aged 2 and 3 years were 1.11 and 1.15, respectively, at an unacceptable health risk level. The hazard quotients of dietary Cd intake in children of other ages were less than 1, at an acceptable health risk level. Staple foods were the most significant contributor to the dietary Cd intake in children, and the contribution ratio of non-carcinogenic risk of dietary Cd intake in all age groups were more than 35%, the proportion of non-carcinogenic risk in children aged 6-8 and 9-11 years were as high as 50%. This study provides scientific basis for the health of children in East China.

Health risk assessment of heavy metal concentration in muscle of Chelon auratus and Chelon saliens from the southern Caspian Sea

Heavy metals are one of the most serious pollutants in aquatic ecosystems, and their accumulation in fish products causes harmful effects on human health. In this context, we set out to determine the concentrations of heavy metals in the muscle of two fish species of commercial interest, Chelon auratus and Chelon saliens on the south coast of the Caspian Sea. We aimed to assess the degree of environment contamination in this area and to estimate the potential risk to human health derived from the consumption of fish. The mean concentrations of the different metals analysed were very varied in both species. In fact, some concentrations exceeded the permissible limits for the protection of human health for Cd and Pb, and some values of As were above those referenced by other authors in same species in the Caspian Sea. None of the estimated daily intake values exceeded the tolerable intake based on the consumption under consideration. Nonetheless, the accumulative hazard values evidenced a potential risk to human health, Pb and Hg being those giving a higher target hazard quotient. The cancer risk from exposure to As from fish consumption in children was above the "acceptable" risk to life. Thus, in view of the accumulative nature of heavy metals, a moderate and non-abusive fish consumption in this area, particularly in children, would be recommendable.

Health risk assessment of heavy metals in Coptodon zillii and Parachanna obscura from a tropical reservoir

In this study, the concentrations of trace metals were examined in commercially important fish, Coptodon zillii and Parachanna obscura from Osu reservoir. These were with a view to providing baseline information on the levels of heavy metals and its associated risks to human health through fish consumption. Fish samples were collected fortnightly for five months using fish traps and gill nets with the assistance of local fisherman. They were brought into the laboratory in an ice chest for identification. The fish samples were dissected and the gills, fillet and liver kept in freezer and later analyzed for heavy metals based on Atomic Absorption Spectrophotometric (AAS) method. The data collected were subjected to appropriate statistical software packages. The results revealed that the concentration of the heavy metals in P. obscura and C. zillii across the tissues were not significantly different (p > 0.05) from each other. Also, the mean concentration of heavy metals in the fish were below the recommended limits of FAO and WHO. The target hazard quotient (THQ) for each heavy metals were below one (1) while the estimated hazard index (HI) for C. zillii and P. obscura showed no threat to human health risk through the consumption of the fish species. However, continuous consumption of the fish could probably cause health risk to the consumers of the fish. According to the study's findings, human consumption of fish species with low concentration of heavy metals at the current accumulating level is safe.

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.

Toxicity risks associated with trace metals call for conservation of threatened fish species in heavily sediment-laden Yellow River

Trace metals and metalloids in aquatic ecosystems may lead to adverse effects on the survival of fish, especially in the sensitive life stages of vulnerable species. It is still unknown whether threatened fish species in the heavily sediment-laden Yellow River are exposed to toxicity risks associated with multiple trace metals. Herein, we analyzed the concentrations of trace metals in aquatic environmental media and fish tissues across the Yellow River mainstream and assessed the level of metal toxicity to threatened fish. Significantly different concentrations of trace metals in fish tissues were measured between at least two categories among near-threatened, vulnerable, endangered, and critically endangered fish. No metal showed a higher concentration in demersal fish than in pelagic fish. Substantially low metal toxicity was observed for the gill of Rhinogobio nasutus (near-threatened) in the upper reaches, as well as for the gill and liver of Silurus lanzhouensis (endangered) in the middle reaches. High contents of suspended sediment in water and high metal concentrations in sediment and suspended matter could influence the survival and reproduction of fish, especially those already with threatened status.

Determination of Heavy Metal Levels and Health Risk Assessment of Raw Cow Milk in Guelma Region, Algeria

During the recent decades, adverse effects of unexpected contaminants, such as heavy metals on raw cow milk quality, have threatened human health. The objective of this study was to determine heavy metal levels in raw milk collected from autochthonous bovine breeds in the eastern region of Algeria. Eighty-eight pooled milk samples were analyzed using atomic absorption spectrometry for Pb, Cd, Cr, Cu, Ni, Fe, and Zn, and dietary risks were estimated for infants, children, and adults with minimum, average, and maximum milk consumption scenarios. Results revealed that Pb (0.94 ± 0.49 mg/kg), Cd (0.03 ± 0.01 mg/kg), and Cu (0.14 ± 0.08 mg/kg) levels in all analyzed samples were higher than their corresponding maximum residue levels (MRLs). The task hazard quotient (THQ) values suggest potential risk for infants in the three scenarios from Pb, Cd, and Cr; for children in the three scenarios from Pb and in the high scenario from Cr; and for adults in the medium and high scenarios from Pb. The hazard index (HI) values were higher than 1, and the contributions of each metal to the overall HI followed a descending order of Pb, Cr, Cd, Ni, Zn, Cu, and Fe with values of 68.19%, 15.39%, 6.91%, 4.94%, 3.42%, 0.88%, and 0.28%, respectively. Our results indicated that there may be a potential risk of heavy metals, especially Pb, for infants through raw cow milk consumption. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metal effects in future studies.

Fermentation affects heavy metal bioaccessibility in Chinese mantou

Effect of different fermentation methods on heavy metal bioaccessibilities in wheat flour is undetermined. In this work, gastric and gastrointestinal heavy metal bioaccessibility in wheat flour products (control-wheat dough, T1-mantou made with normally fermented dough, T2-mantou made with over-fermented dough and T3-mantou made with over-fermented dough + Na₂CO₃) made from two wheat flour samples (NX and QD) was assessed via a modified physiologically-based extraction test. Cadmium, Zn and Mn bioaccessibility in the gastric phase (GP) was greater than in the gastrointestinal phase (GIP), yet the opposite was observed for Cu (p < 0.05). Lead bioaccessibility in the GIP of the QD sample was 1.37-4.08 times greater than that in the GP, while only the control had greater bioaccessibility in the GIP than that in the GP (p < 0.05) for the NX sample. Treatments T2 and T3 had greater Cd, Cu, Zn and Mn bioaccessibilities than the control and T1 in the GP (p < 0.05). In the GIP, however, only T3 had greater Mn bioaccessibility than the control for the NX sample. Enhanced degradation of the heavy metal-phytate following over-fermentation may have led to greater heavy metal bioaccessibility. Results should help food processors reduce human absorption of excessive heavy metals present in wheat flour foods.

Contamination of Selected Toxic Elements in Integrated Chicken-Fish Farm Settings of Bangladesh and Associated Human Health Risk Assessments

The presence of trace elements in the environment can contaminate a food chain of an agro farm in various ways. Integrated chicken-fish farms (i.e., where poultry chicken and fish are cultivated in same places) are getting popular nowadays to meet the demands of a balanced diet. The present study conducted a health risk assessment on the basis of selected heavy metal (i.e., Cr and Pb) and metalloid (i.e., As) contamination in this type of farm in Bangladesh. Samples of various types were collected from different farms between September 2019 and March 2020. The concentrations of the elements were checked by Flame-AAS and HG-AAS. Our findings demonstrated that the elements' concentrations in fishes were simultaneously induced by the habitation and bioaccumulation through the food chain of the farm. The concentrations of As and Pb in the chicken parts and Cr and As in some fishes were greater than the highest limits set by different permissible standards. Overall, the metal concentration obtained in different samples was in descending order: sediment > droppings > different fish parts > various species of chicken > pond water. Among the pollutants, As gave target hazard quotient (THQ) values higher than 1 for all the species, suggesting health risks from the intake of fishes and chicken. However, there was non-target cancer risk present while considering all the elements together. Notably, the study found carcinogenic risks of As, Pb, and Cr for humans due to poultry and/or fish consumption; the identified health risks associated with the integrated farming setting will be crucial in further tackling strategies. Investigation of the possible sources of heavy metals in commercial chicken feeds and regular monitoring of groundwater used for agro-farming are highly recommended to reduce the burden.

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.

Assessment of heavy metal accumulation in Penaeus monodon and its human health implications

Asian tiger shrimp Penaeus monodon (P. monodon) of Chilika lagoon, India was studied regarding the metal accumulation and its associated human health risks. It showed a tendency of metal accumulation in the following order: Zn > Ni > Cu > Co > Cr > Pb > Cd. A two-way ANOVA indicated the metal accumulation was insignificant with respect to season (n = 421, p = 0.59) and sector (n = 32, p = 0.61). The estimated daily intake (EDI), targeted hazard quotient (THQ) and hazard index (HI), and carcinogenic risks (CR) revealed no potential human health risks and were safe for consumption. The pollution load index (PLI) of <1, Geo-accumulation index (Igeo,) and contamination factor (CF) indicated that the study area was unpolluted. This pioneering study highlighted that P. monodon was nurtured well in the healthy habitat of Chilika lagoon and the fair level of metal content made it an excellent source of dietary components.

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.

Concentration of essential and non-essential elements and carcinogenic / non-carcinogenic health risk assessment of commercial bee pollens from Turkey

BACKGROUND

Bee pollen, known as a natural super-food with valuable nutritional ingredients, is regarded as a good indicator of ecotoxic substances, such as potentially toxic elements (PTEs). Therefore, this study aims to examine the concentrations of selected PTEs (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Se, Sn, Sr, V, Zn) in bee pollen purchased from online markets in Turkey and perform a health risk assessment to identify the potential risk to consumers.

METHODS

The quantitative analyses were conducted by inductively coupled plasma optical emission spectrometry (ICP-OES).

RESULTS

The mean values of essential PTEs in decreasing content order were Mg > Fe > Zn > Mn > Cu > Ni > Se > Cr > Mo >Co = V. Regarding the results of the study, daily consumption (40 g for adult or 20 g for children) of commercial bee pollen can recompense 20-35 % of daily Cu, Mn, Se requirements for children, adults, pregnant, and breastfeeding women. The decreasing content order of non-essential elements was Al > Sn > Sr > Ba > Pb > As. Cadmium and Hg concentrations were below the detection limits in all the samples. In terms of food and public health; detection of the PTEs concentrations is necessary to assess the quality and safety of bee pollen before consumption. According to the carcinogenic and non-carcinogenic risk assessments; commercial pollen consumption does not pose a health risk to either children or adults for the PTEs monitored in this study.

CONCLUSION

We conclude that bee pollen is an ideal indicator for the monitoring of environmental pollution of PTEs and also a valuable source of essential elements. This study highlights the need to develop standards that regulate acceptable concentrations of PTEs.

Evaluation of potential toxic heavy metal contamination in soil, fly ash, vegetables and grain crops along with associated ecological and health risk assessment of nearby inhabitants of a thermal power station in Jharkhand (India)

The present study aimed to evaluate the potential toxic heavy metal (PTHM) concentrations and associated ecological and health risk of nearby inhabitants (child and adult populations) of the Bokaro thermal power station (BTPS), Jharkhand, India. The fly ash containing PTHMs is released from the thermal power plant and contaminates the soil of the nearby agricultural area, roadside area and residential area. Furthermore, PTHMs cause ecological risk as well as carcinogenic health effects in adults. Inhabitants are exposed to PTHMs through exposure pathways (for instance, direct ingestion, dermal contact and air inhalation), and PTHMs were examined in this study by calculating the estimated daily intake (EDI). The contamination factor (C_f) of Cd exceeded the threshold value throughout the study area, whereas the C_f of Hg was observed higher only in roadside soil (RSS). The geoaccumulation index (I_geo) of Cd was higher in the top soil of agricultural soil (AS) (7.39) and RSS (9.38). The level of PTHMs was monitored slightly higher in the topsoil of RSS. The ecological risk index (Eri) was detected to be the highest in RSS (1628.9). The permissible limit of Cd (0.05 mg kg^-1) and Pb (0.1 mg kg^-1) for all sampled vegetables and grain crops was surpassed. The transfer factor (TF) of the studied vegetables and grain crops was in the order of Cd > Cr > Pb > Hg > As. The results of the present study concluded that the hazard quotient (HQ) values for all PTHMs analysed in soil throughout the study area were < 1, which indicates that the child population was within the safe limit. However, the adult population was at a high risk of non-carcinogenic health effects due to increased permissible limits of Cd, Pb and Cr in vegetables and grain crops whereas the target carcinogenic risk (TCR) of Pb and Cr was higher and indicated that there may be a health risk of cancer in adults.

Heavy metals in Chinese freshwater fish: Levels, regional distribution, sources and health risk assessment

China is a major producer and consumer of freshwater fish, which can provide nutrients to the human body but is also of great concern because of the bioaccumulation and amplification of heavy metals that are directly related to human health. In this paper, we reviewed the accumulation and distribution patterns of lead (Pb), arsenic (As), mercury (Hg), cadmium (Cd), and chromium (Cr) in freshwater fish from 2010 to 2020 in nine basins of China (Yangtze River, Pearl River, Yellow River, Haihe River, Huaihe River, Songhua and Liaohe River, Continental, Southeast, and Southwest basins), assessed the health risks, and compared them with those in Chinese marine fish, international freshwater fish, Chinese wild freshwater fish, and artificially cultured freshwater fish. The results showed that 1) the pollution status of the five heavy metals in freshwater fish from nine basins in China is at an intermediate level internationally; 2) the magnitude of heavy metal concentration in four types of artificially farmed freshwater fish and wild freshwater fish is ranked as follows: rice-farmed fish < cage-farmed fish < pond-farmed fish < lake-farmed fish < wild fish; 3) the noncarcinogenic risk factors for heavy metals in freshwater fish in the nine major basins in China were <1 for adults, but the noncarcinogenic risk factors for heavy metals in freshwater fish in the Yellow River, Yangtze River, Pearl River, Songhua and Liaohe River, and Huaihe River basins were all >1 for children.

Pollution status of heavy metals and metalloids in Chinese lakes: Distribution, bioaccumulation and risk assessment

Due to intensive human activities, most of Chinese lakes are suffering from the pollution of heavy metals and metalloids. Previous studies on heavy metals and metalloids in Chinese lakes were limited to a few lakes and mainly focused on sediments, to date the knowledge on heavy metals and metalloids in multiple media of Chinese lakes from a national perspective is scarce. We collected the data of nine heavy metals and metalloids including Copper (Cu), Cadmium (Cd), Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr), Nickel (Ni), Zinc (Zn), and Manganese (Mn) in water, surface sediments, and fish of 87 Chinese lakes sampled in the period from 2009 to 2019 from the literature, summarized the distribution of heavy metals and metalloids, evaluated their pollution, and apportioned their sources from a national perspective. Concentration of individual heavy metal and metalloid in water, surface sediments, and fish in Chinese lakes was in the ranges of 0.0080-282 μg/L, 0.020-33858 μg/g, and 0.00030-207 μg/g, respectively. 5.6 % and 33.3 % of lake water were polluted by Cd and As. 88.2 %, 78.6 %, and 66 % of lake sediments were polluted by Cd, Hg, and As. 35.3 %, 11.3 %, 52.4 %, and 12.8 % of Cd, Pb, As, and Cr concentrations in lake fish exceeded the food limits. Concentrations of heavy metals and metalloids in fish viscera were higher than those in other organs. Higher partition coefficient and bioaccumulation factors were found for Pb and Cd, Hg and Zn, respectively. Concentrations of heavy metals and metalloids in both water and sediments of lakes in eastern China were higher than those in western China. Concentrations of heavy metals and metalloids in both lake water and sediments of urban lakes were higher than those of rural lakes. Lakes with extremely high ecological risk of heavy metals and metalloids were mainly located in central China and eastern China. Pollution of heavy metals and metalloids in Chinese lakes was closely correlated with regional economic development. Heavy metals and metalloids in Chinese lakes were mainly derived from industrial, domestic, and mixed discharges. Cd and Hg were selected as the heavy metals for priority control in Chinese lakes.

Potentially Harmful Elements Accumulation and Health Risk Assessment of Edible Fish Tissues Caught from the Phander Valley, Northern Pakistan

This study investigated the concentrations of potentially harmful elements (PHE) in edible tissues of trout fish (Salmo trutta) in the Phander Valley, Northern Pakistan. For this purpose, fish were sampled from the Phander Valley (Gilgit River and Phander Lake). PHE concentrations in edible fish tissues (muscle, fins, and skin) were determined using atomic absorption spectrometry (AAS, AAnalyst 700, Perkin Elmer, USA). Among PHE, zinc (Zn) showed the highest concentration of 1097 μg/kg in the skin, followed by manganese (Mn) of 241 μg/kg in the muscle, and the lowest of 3.78 μg/kg for cadmium (Cd) in fins. The concentration of PHE in fish tissues of the study area was observed within the threshold limits set by the food and agriculture organization (FAO). PHE concentration of fish tissues was used for the calculation of chronic risk assessment using the chronic daily intake (CDI) and hazard quotient (HQ) indices. The highest CDI values were observed for Zn through fish tissue consumption in juveniles, followed by Mn, and the lowest for Cd in adults. The HQ values were observed less than 1 for adults through PHE consumption in fish tissue; however, that of juvenile surpassed the threshold limit through Cd consumption in all studied tissues and that of Pb in the muscle and skins only. Higher HQ values than the threshold limit could pose a potential chronic risk to the exposed community. Spearman's non-parametric correlation showed a varying degree of correlation among PHE in fish tissues and canonical discriminant analyses were used to differentiate the tissues based on PHE accumulation tendencies.

Biomonitoring of mercury in water, sediments, and fish (brown and rainbow trout) from remote alpine lakes located in the Himalayas, Pakistan

Mercury (Hg) contamination of aquatic ecological units and subsequent bioaccumulation are major environmental problems of international scope. Moreover, the biogeochemistry of Hg in the remote alpine lakes aquatic ecosystem in the Himalayas remains largely unexplored. The current study investigated Hg concentrations in different environmental compartments such as water, fish, and sediments in the remote alpine lakes (RALs) including Glacial-fed Lake, Ice melting-fed Lake, and Rain-fed Lake in northern areas of Pakistan. The mean concentration of Hg in Rain-fed Lake water was (1.07 µg L^-1), Ice melting-fed Lake (1.16 µg L^-1), and Glacial-fed Lake (1.95 µg L^-1). For fish muscle tissues, mean concentration of Hg was 1.02 mg kg^-1 in the Rain-fed Lake, and 1.2 mg kg^-1 for the Ice melting-fed Lake, and 1.51 mg kg^-1 in the Glacial-fed Lake. Meanwhile, 0.27 mg kg^-1 was observed for sediments in the Rain-fed Lake, 0.33 mg kg^-1 for the Ice melting-fed Lake, and 0.38 mg kg^-1 for the Glacial-fed Lake, respectively. Chronic daily intake (CDI) and potential health quotient (PHQ) for water showed high health risk in Glacial-fed Lake and low in Rain-fed Lake (PHQ < 1). The target hazard quotient (THQ) values for both the Brown and Rainbow trout in all the studied lakes water were less than 1, indicating no health risk. Furthermore, the Hg level showed high level of contamination in the sediments of all the studied lakes (190 ≤ RI < 380). Overall, Glacial-fed Lake water was more polluted with Hg, as compared to Rain-fed Lake and Ice melting-fed Lake. In the light of the abovementioned results, further research work is urgently needed to shed light on the biological and geochemical monitoring of Hg in arid high-altitude ecosystems along with source identification, mercury speciation, and other potential pollutants.

Levels of metals and elements in tissues of fish species in the Kızılırmak River (Turkey) and assessment of health risks and nutritional benefits

Although the Kızılırmak River, the longest river in Turkey, is home to many fish species, there are a few studies reporting metal levels in fish in the river. The contents of 17 metals and elements (MEs) in various tissues of three fish species and surface water from the river were investigated. Significant differences in the ME levels among tissues were recorded, and the highest levels of most MEs were recorded in the gills and liver. The results revealed that correlations between MEs in tissues and fish size were not clear and consistent. Among the MEs, P (6058-109489) and Zn (933-47556) had the highest bioconcentration factor values. The levels of As and Cd in the river water exceeded water quality criteria. Health risk assessment methods (Target Hazard Quotient, Estimated Daily Intake and Lifetime Carcinogenic Risk) indicated that consumption of the studied fish species is safe. It was estimated that a weekly consumption of 490 g of C. gibelio, or 350 g of C. carpio or 280 g of T. tinca would not cause any health risks. Furthermore, it was found that fish species would provide significant benefits in terms of intake of nutrients such as P, K, Ca, Mg, Cu, Zn, Fe and Mn. These findings revealed that nutritional benefits from consumption of fish species outweigh the health risks posed by metals in fish.

Distribution and source apportionment of toxic and trace elements in some benthic and pelagic coastal fish species in Karnaphuli River Estuary, Bangladesh: Risk to human health

The Karnaphuli River is one of the prime and most important streams in the southeastern part of Bangladesh. The favorable water current and the geographic location have rendered the Karnaphuly River estuary a suitable habitat and a breeding ground for diverse fish species. Reversely, this estuary has been polluted by discharges from many point and non-point sources due to its location in the catchment area of a heavily industrialized area, Chattagram port city. However, published research concerning the status of toxic and trace elements in some commercially important benthic and pelagic coastal fish species in Karnaphuli River estuary was not found in the existing literature. Therefore, it's an important field of study on the assessment of toxic and trace elements concentration in the commercially important benthic and pelagic coastal fish species and their health taxation in the Karnaphuli River Estuary. Energy dispersive X-ray fluorescence (ED-XRF) was used to quantify trace metal concentration in edible parts of the fish species. This study revealed that the rank of the trace metals concentration was as follows (mg/kg): Zn (37.1) > Mn (16.12) > V (11.16) > Cu (9.49) > Rb (5.62) > Pb (2.98) > Cr (1.59) > Co (1.17). The F-test showed that a significant difference at 95 % confidence level in the distribution pattern of trace metals concentration among the examined fish species in the study area. The metal pollution index (MPI) in the muscle of fishes were found to be in the following order: L. bata > P. monodon > T. cirratus > M. bleekeri > O. pabda > H. nehereus > L. calcarifer > P. argenteus > P. paradiseus > T. toli, and the MPIs for most of the benthic fish species were higher compared to the pelagic fishes. On the other hand, the examined fish species were significantly bio-accumulative with the highest bio-accumulation factor value for benthic species. The multivariate analysis identified that the sources of the trace metals were associated with anthropogenic activities. For the human health risk assessment concern, estimated daily intake, target hazard quotient and cancer-causing risk were estimated. The results for non-cancer hazardous index values were found to be lower than unity. On the other hand, the total cancer risk data ranging from 1.24E-05 to 1.70E-05 were fallen within the range for the threshold values (1.0E-06 to 1.0E-04). However, considering the suggested values set by the environmental and regulatory agencies, it has been recommended that no significant non-carcinogenic and cancer-causing health risk for humans was seen due to the consumption of the studied fish species.

A comprehensive review of heavy metal pollution in the coastal areas of Bangladesh: abundance, bioaccumulation, health implications, and challenges

The coastal zone of Bangladesh, with a population density of 1278 people per square kilometer, is under serious threat due to heavy metal pollution. To date, many studies have been conducted on the heavy metal contamination in soils, water, aquatic animals, and plants in the coastal zone of Bangladesh; however, the available information is dispersed. In this study, previous findings on the contamination levels, distributions, risks, and sources of heavy metals in sediments and organisms were summarized for the first time to present the overall status of heavy metal pollution along coastal regions. Earlier research found that the concentrations of various heavy metals (HMs), particularly Co, Cd, Pb, Cu, Cr, Mn, Fe, and Ni in water, sediment, and fish in most coastal locations, were above their permissible limits. High concentrations of HMs were observed in sediments and water, like Cr of 55 mg/kg and 86.93 mg/l in the ship-breaking areas and Karnaphuli River, respectively, in coastal regions of Bangladesh. Heavy metals severely contaminated the Karnaphuli River estuary and ship-breaking area on the Sitakundu coast, where sediments were the ultimate sink of high concentrations of metals. Sedentary or bottom-dwelling organisms like gastropods and shrimp had higher levels of heavy metals than other organisms. As a result, the modified PRISMA review method was used to look at the critical research gap about heavy metal pollution in Bangladesh's coastal areas by analyzing the current research trends and bottlenecks.

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.

Seasonal behavior and accumulation of some toxic metals in commercial fishes from Kirtankhola tidal river of Bangladesh - A health risk taxation

Contamination of fish with heavy metals (Heavy metals) is one of the most severe environmental and human health issues. However, the contamination levels in tropical fishes from Bangladesh are still unknown. To this end, the evaluated concentrations of arsenic (As), chromium (Cr), cadmium (Cd), and lead (Pb) in 12 different commercially important fish species (Tenualosa ilisha, Gudusia chapra, Otolithoides pama, Setipinna phasa, Glossogobius giuris, Pseudeutropius atherinoides, Polynemus paradiseus, Sillaginopsis panijus, Corica soborna, Amblypharyngodon mola, Trichogaster fasciata, and Wallago attu) were collected from the Kirtankhola River assess human health risk for the consumers, both in the summer and winter seasons. Toxic metals surpassed the acceptable international limits in P. atherinoides, P. paradiseus, S. panijus, C. soborna, and W. attu. The target hazard quotient (THQ) revealed that non-carcinogenic health effects (HI < 1) for children and adults, and the carcinogenic risk (CR) indicated safety. Results show that children are more susceptible to carcinogenic and non-carcinogenic hazards from higher As. The multivariate analysis justified that heavy metals were from anthropogenic actions. The lessening of toxic metals might need strict rules and regulations as metal enrichment would continue to increase in this tidal river from both the anthropogenic and natural sources.

Fish Behavior as a Neural Proxy to Reveal Physiological States

Behaviors are the integrative outcomes of the nervous system, which senses and responds to the internal physiological status and external stimuli. Teleosts are aquatic organisms which are more easily affected by the surrounding environment compared to terrestrial animals. To date, behavioral tests have been widely used to assess potential environmental risks using fish as model animals. In this review, we summarized recent studies regarding the effects of internal and external stimuli on fish behaviors. We concluded that behaviors reflect environmental and physiological changes, which have possible implications for environmental and physiological assessments.

Nutritional value and bioaccumulation of heavy metals in nine commercial fish species from Dachen Fishing Ground, East China Sea

The study evaluated the nutritional quality in muscle tissues of nine commercially important marine fish species. And the concentrations of trace metals (i.e. As, Hg, Cu, Pb, Cr, Cd and Zn) in the muscles (edible part) and tissues (gill and liver) of fishes caught from Dachen fishing ground, the coast of Zhejiang Province, East China Sea, were determined, and the values of target hazard quotient (THQ) and the carcinogenic risk (TR) were calculated for assessing human health risk. Significant differences(P < 0.05) were observed in the proximate chemical composition of fish muscles in these species. The muscle protein content of fish species ranged from 12.36 to 23.41%. The muscle lipid content of fishes ranged from 0.48 to 2.54%. The accumulation capacity of heavy metals (except Cr) in livers and gills was higher than that in muscles. In addition, the accumulation ability of most fishes is related to the water layer they live, the fishes living in the demersal layer showed more accumulation of heavy metals than the middle-upper layer(except Cu). Estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI) and the carcinogenic risk (TR) assessed for potential human health risk implications suggest that the values were within the acceptable threshold for human. However, the carcinogenic risk(TR) of As and Cr was close to the critical limit (10^–4). Therefore, in order to ensure the health and safety of human consumption, the continuous monitoring of heavy metals in Dachen fishing ground area is suggested.

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.

Bioaccumulation and potential human health risks of metals in commercially important fishes and shellfishes from Hangzhou Bay, China

Hangzhou Bay is facing severe anthropogenic perturbation because of its geographic position. We studied species-specific bioaccumulation of metals in commercially important fishes and shellfishes, and calculated the potential human health hazards through their consumption, which has not been reported earlier from this area. The hierarchy of metal concentration in organisms was in the decreasing order of Zn (10.32 ± 7.13) > Cu (2.40 ± 2.66) > As (0.42 ± 0.26) > Cr (0.11 ± 0.08) > Cd (0.07 ± 0.07) > Pb (0.05 ± 0.02) > Hg (0.012 ± 0.009). Except for Cd and As concentrations in fishes, metal concentrations have not exceeded the national and international guideline values. P. laevis and P. trituberculatus were the most bioaccumulative of the species studied. According to the non-carcinogenic risk assessment, children were more susceptible to metal contamination than adults. The carcinogenic risk (CR) values indicated that children were likely to experience carcinogenic threats for taking cancer-causing agents As and Cd through fish consumption. In terms of organisms, intake of two crab species, P. trituberculatus and E. sinensis, as well as the oyster species P. laevis, could be detrimental to consumers.

Tissue-specific distribution and bioaccumulation pattern of trace metals in fish species from the heavily sediment-laden Yellow River, China

The Yellow River is one of the largest contributors to the global riverine sediment flux from the land to the ocean. Tissue-specific bioaccumulation of trace metals in fish from heavily sediment-laden rivers remains unclear to date. The concentrations and distributions of trace metals in water, suspended matters, sediments, and various fish tissues were investigated in the mainstem of the Yellow River were investigated. The concentrations of most metals in abiotic media were high in the Gan-Ning-Meng of upstream and downstream segments, and were highest in fine-sized suspended matters. The highest concentrations of most metals were in the gill and liver, followed by the gonad, and lowest in the muscle, and there were a significant overall differences among the tissues. The concentrations of metals in some tissues (e.g., muscle and gill) significantly differed among regions and feeding habits. The highest values of the bioaccumulation factor for suspended matters (BF_SPM) were observed in the midstream region (e.g., reaching to 19.0 for Se in the liver). This was determined by metal type and tissue specificity, food composition, and concentration of metals in abiotic media. The results highlight the significance of suspended matters for the distribution of trace metals in abiotic and biotic media.

Bio-functionalized zinc oxide nanoparticles: Potential toxicity impact on freshwater fish Cyprinus carpio

There is a growing concern nowadays over the exposure of nanomaterials and their effects in aquatic life. In spite of reporting the changes in physiology, reproduction and behaviour in fish by different nanoparticles, the molecular events underlying in the aquatic bodies due to the toxicity of zinc oxide nanoparticles (ZnO NPs) are mainly unexplored. Therefore, the present study carried out an ex vivo exposure of ZnO NPs at various concentrations (0.382, 0.573 and 1.146 mg L^-1) in freshwater fish Cyprinus carpio to investigate the potential adverse effects. The results revealed that ZnO NPs exposure altered the haematological parameter and induces the reactive oxygen species (ROS) that leads to elevation of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidise (GPx), glutathione S-transferase (GST) and reduced glutathione (GSH) activity in C. carpio. Furthermore, histopathological analysis exhibited that the ZnO NPs caused lamellar fusion, aneurism, cytoplasmic vacuolation, nuclear alteration, necrotic muscle fiber and pyknotic nuclei in the gills, liver and muscles of C. carpio. ZnO NPs exposure significantly up-regulated the overlapping expressions of SOD1, CAT, GPx1a, GST-α, CYP1A, and Nrf-2 genes. A higher level of Zn bioaccumulation was observed in the following order: gill (35.03 ± 2.50 μg g^-1), liver (5.33 ± 0.73 μg g^-1) and muscle (2.30 ± 0.20 μg g^-1) at 1.146 mg L^-1 exposure of ZnO NPs. Hence, the current study indicated that the biogenic ZnO NPs generate toxicity in fishes by modifying the antioxidant defense mechanisms, histomorphology, and oxidative stress encoding genes.

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.

The Accumulation and Transformation of Heavy Metals in Sediments of Liujiang River Basin in Southern China and Their Threatening on Water Security

Heavy metal (HM) pollution in sediments is tightly related to the security of water quality in rivers, but the accumulation and conversion of HMs are poorly researched, so that a field study was conducted as an example in the Liujiang River Basin. Seven HMs were analyzed to determine between the overlying water and sediments. Moreover, the regulation of HMs speciation and environmental factors in their accumulation and conversion were identified. The obtained results suggested the HM concentrations in water are far below the primary standard of water quality, but in sediments, the contents of Cd and Zn are significantly higher than their corresponding baseline of soil. Only Cd and Pb are dominantly in non-residual form (carbonate-bound fraction and reducible fraction, respectively). The non-significant correlations suggested pH and Eh may be hard to influence HMs in water, while the significant correlations highlighted the regulations of Eh, organic matter and mean grain size on the accumulation of metals in sediments. The opposite correlations between EC, TDS, pH and Cd confirmed the emission of acid wastewater contributed to the accumulation of Cd in sediment. The conversion of metals between water and sediments were found to be significant only in specific forms of Cd, As, Cu, Zn and Pb, suggesting the conversion of HMs in sediments should be largely regulated by their specific forms. The very high risk disclosed by the higher values of Eri and RI are only found upstream, while the higher risk of Cd should be treated as a critical environmental threat.

The Bioaccumulation and Health Risk Assessment of Metals among Two Most Consumed Species of Angling Fish (Cyprinus carpio and Pseudohemiculter dispar) in Liuzhou (China): Winter Should Be Treated as a Suitable Season for Fish Angling

Wild fish caught by anglers were validated to be commonly polluted by metals, but their contamination status could be varied with changing seasons. To determine the seasonal variation in metal pollution and health risks in these fish, this study took Liuzhou City as an example to investigate the concentrations of eight metals in two dominant angling fishes (Cyprinus carpio and Pseudohemiculter dispar) collected, respectively, in winter and summer. The obtained results suggested the mean concentrations of metals in fish are overall lower in winter. Only Cr, Zn, and Cd in some fish were beyond the thresholds in summer. The significant correlations between fish length and weight and most metals suggested the biological dilution effect could exert its influence in winter. The similar distribution of metals in winter suggested that metal bioaccumulation should be manipulated by living habitats, while the inconsistent distribution of metals in summer may be related to the variation in feeding behavior. The metal pollution index (Pi) values were all below 0.2 in winter, which suggested no metal contamination in fish, but most fish were found to be mostly contaminated by Cr and Cd in summer, which was confirmed by their Pi > 0.2. The fish could be consumed freely in winter due to the total target hazard quotient (TTHQ) below 1, while the consumption of fish was not entirely safe in summer, particularly for children, due to TTHQ values that were generally beyond 1. Given the higher weekly recommended consumption of fish in winter, winter should be treated as a suitable season for fish angling.