Heavy metal (Pb, Cu, Zn, and Cd) concentrations in the water and muscle of common carp (Cyprinus carpio) fish and associated non-carcinogenic risk assessment: Alagol wetland in the Golestan, Iran

Heavy metals and microplastics derived from laboratory effluents enhance toxicological risks to the ecosystems of canals in Bangladesh

The occurrence of chemical effluents in different water bodies is an emerging concern. However, the effect of laboratory effluents on the canal ecosystem in Bangladesh is largely unknown. In this study, we collected 10 components of the canal ecosystem including sediments, water, fish, crabs, snails, phytoplanktons, and weeds specifically from canals that directly receive laboratory effluents. We examined the occurrence of both the essential (Fe, Mn, Cu, and Zn) and toxic (Pb, Cd, Cr, Co, Ni, and As) metals as well as microplastics (MPs). Results explored that laboratory effluents strongly interact with the components of the canal ecosystem and enhance the abundance of toxic metals in the canal hydrosystem. Furthermore, diverse types of MPs including fibers, fragments, and microbeads were observed in all components of the canal ecosystem. Remarkably, our results unveiled that the co-occurrence of pollutants was more severe in benthic organisms like snails or crabs might be due to their omnivorous food habits. The cumulative pollutant accumulation was much higher in all components of the canal ecosystem indicating a greater ecological risk. Although the potential risk index (RI) or hazardous index (HI) from fish ingestion was found within acceptable limits, the biomagnification of pollutants due to repeated ingestions may have strong ecotoxicological impacts even at very low concentrations.

Hg, Cd, and Pb in fish of the Moulouya River, Morocco, and human health risk

Concentrations of toxic metals (Hg, Pb, and Cd) were determined in the muscles of Lepomis macrochirus, Barbus callensis, and Barbus nasus caught from the Moulouya River of Morocco by graphite furnace (for Pb and Cd) and cold vapour (for Hg) atomic absorption spectrometry, after acid digestion. Although the concentration of metals in some species was relatively high, no health risk has been identified in comparison to the maximum limits as set by the European Commission. The order of increasing concentrations was Cd < Hg < Pb. Calculated Target Hazard Quotients and Hazard Indices were below 1, indicating that the intake of metals via consumption of the muscles of both fish species does not represent a hazard to human health.

Seasonal variation of heavy metals in water and Cyprinus carpio L. from Umiam Lake reservoir of Meghalaya, India: Potential health risk assessment for human consumption

The purpose of this study is to assess the seasonal variation of heavy metal concentration in water and fish tissues of common carp (Cyprinus carpio L.) from the Umiam Lake reservoir located in the Ri bhoi district of Meghalaya, India, and to elucidate the possible human health risk of ingesting fish captured from the contaminated lake. Results show significant (p < 0.05) seasonal differences of heavy metal concentrations in the water and different tissues of fish Cyprinus carpio L.. The total concentration of heavy metals in the water exceeds the WHO and BIS standards and thus poses a significant threat to the aquatic flora and fauna of the reservoir. The heavy metal concentrations in fish tissues were tissue-dependent, where the average concentration of heavy metals in all the tissues of Cyprinus carpio L. was in the order of Cr > Pb > Cu > Cd. In addition, the health risk assessment suggests that the heavy metals in the fish muscle from the Umiam Lake reservoir might have adverse effects on human. Therefore, the overall results of the study provide an understanding on the seasonal distribution of heavy metals in water, provide insight on their bioaccumulation in the fish tissues, and highlights the potential health risk for the local population of long-term fish consumption from Umiam Lake reservoir.

Ecological risk assessment for metals in sediment and waters from the Brazilian Amazon region

Pollution by metals is a matter of concern around the world. In recent decades, the high population growth in urban centers has significantly magnified the entry of these pollutants into aquatic ecosystems. The Amazon region, intense migratory flow, gold mining, and industrialization have been considered the main driving forces for increasing metal pollution. Thus, the main aim of this study is to conduct, for the first time, an Ecological Risk Assessment (ERA) based on metal concentrations measured in the sediment and water of several aquatic environments from the Amazon basin, based on the risk quotient values (RQ = measured environmental concentration - MEC/predicted no effect concentration - PNEC). In addition, the metal contamination factor (CF) was estimated. Although metal concentrations in water were generally low, these values were far above the limits established by current national legislation in many areas, showing higher concentrations for the metals Co, Pb, Cr, Cu, and Ni. Concentrations of Mn, Cu, Ba, Pb, Co, Ni, Cr, Zn, Cd, and As were especially high in the sediment for several evaluated environments. The ERA for the water compartment revealed that 56% of the studied areas presented high risk (RQ > 1) for aquatic biota. In the sediment, 66% of the sites presented a high risk and 40% medium risk (RQ = 0.1-1). The CF indicated that 49% of the sampling points had high contamination and only 24%, had low contamination. These results reveal that monitoring studies in the Amazon region, provides important information so that public policies for the preservation of water resources can be strengthened in the Amazon.

Metal(loid)s (As, Cd, Cu, and Zn) in three fish species from a dam after a mine-tailing spill: differential bioaccumulation and potential health risk

The failure of a tailings dam occurred in January 2013 at the Santa María de Otáez mining region (Mexico) released a spill (~ 300,000 m3) on Los Remedios River, which was transported through the San Lorenzo River, and finally to El Comedero (EC) dam. The concentrations of metal(loid)s in the muscle, liver, gills, and guts of three fish species (Cyprinus carpio, Oreochromis aureus, Micropterus salmoides) collected from EC dam were examined twenty months later to assess the performance of the cleaning operations. The bioaccumulation patterns of the metal(loid)s in the tissues were different in the three fish species. Tilapia had the highest Cd (11.23 ± 8.53 µg g-1) and Cu (871 ± 1261 µg g-1) concentrations in the liver, as well as As concentration (83.6 ± 61.7 µg g-1) in the gut, while the highest Zn concentration (745 ± 356 µg g-1) was measured in the gills of the carp. Such variability can be caused by the variant bioavailability of the metal(loid)s and by the feeding habits of each species; and also by the fact that some metals are essential and better regulated by organisms than other non-essential. Compared to a study of tilapia carried out 90 days after mine spill, a decrease was evident in the liver for As, Cd, Cu, and Zn by 129, 5, 10, and 1.7 times, respectively. This revealed that cleaning operations were more efficient for As. The target hazard quotient and the hazard index were < 1, which indicates there will be no risk of consuming muscle in moderated rations of the three fish species.

Metal pollution and potential human health risk assessment in major seafood items (fish, crustaceans, and cephalopods)

Global seafood consumers are increasingly concerned about and prefer safe, high-quality, and hazard-free seafood products. This study investigated various Pakistani processing plants supplying the international market and explored commercially important seafood species (fish, crustaceans, and cephalopods) for metal content, contamination, and potential health risks. The results showed that the metal concentrations differed significantly among species. The metals loads were as Fe > Cu > Zn > Mn > Pb > Ni > Cd > Hg. Contamination factor (CF), pollution load index (PLI), and metal pollution index (MPI), verified negligible contamination of seafood. As assessed by the estimated daily intake, target hazard quotient, hazard index, and carcinogenic risk, the potential human health risks associated with the contaminated seafood were lower than the perceived threat. In conclusion, seafood processing plants export products that meet international food safety standards and are safe for consumers worldwide.

Comparative study on metal concentrations in water, sediments, and two fish species (Cyprinus carpio and Pelteobagrus fulvidraco) from the Wujiang River, China

In order to assess the metal pollution in the Wujiang River, concentrations of Cu, Zn, Fe, Mn, Pb, Cd, As, and Hg in the water, sediments, and two fish species Cyprinus carpio and Pelteobagrus fulvidraco from the middle reaches (Tuomugang, TMG) and lower reaches (Wulong, WL) of the Wujiang River were examined. The results indicated that all metal concentrations were lower than the values for grade one water quality according to the Environment Quality Standard for Surface Water of China (GB 3838-2002). The bioavailable fraction concentrations of Zn, Fe, Mn, Pb, and Hg in WL were significantly higher than those in TMG (p < 0.05), indicating that these metals in sediments of WL have higher bioavailability and mobility. The Cu, Zn, Fe, Pb, As, and Hg were mainly related to the residual fraction, while the Mn and Cd were mainly associated with the non-residual fraction. The risk assessment code (RAC) and the secondary phase to the primary phase (RSP) values indicated that Mn and Cd have a high risk of secondary release. The mean metal concentrations in the liver of the two fish species were higher than those in muscle. The higher metal concentrations of fish in WL suggested that bioaccumulation of metals in fish could be influenced by metal bioavailability. No identical relationships between metal concentrations and fish length were manifested in the present study. The values of target hazard quotient (THQ) and hazard index (HI), and carcinogenic risk (CR) of metals for the consumption of C. carpio and P. fulvidraco indicated that the anglers would likely not experience significant non-carcinogenic risk, but the carcinogenic risk of As cannot be ignored. Thanks to prohibited commercial fishing in the Wujiang River, the metal pollution will probably not pose a health risk to the general public for wild fish consumption.

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.

Determination of metals in estuarine fishes in a metropolitan region of the coastal zone of the Brazilian Amazon

The aim of the present study was to determine concentrations of cadmium, copper, chromium, manganese and iron in fishes in the São Marcos (SMB), São Jose (SJB) and Arraial (AB) Bays. Metal concentrations were determined using inductively coupled plasma optical emission spectrometry. Mean Cd and Cr levels were above the permissible limits set by different international or national guidelines in all three bays, whereas copper levels were well below the maximum acceptable limit. High concentrations of iron were found in all species analyzed, whereas high concentrations of manganese were found, especially in specimens caught in SJB. Spatial analysis indicated significant differences among the elements investigated. Copper was correlated more with SMB and AB as well as the species Macrodon ancylodon (carnivore) and Sciades herzbergii (omnivore). Cadmium and iron were strongly associated with AB and SJB, while manganese was only associated with SJB, mainly in carnivorous and herbivorous species.

A comprehensive systematic review and health risk assessment of potentially toxic element intakes via fish consumption in Iran

Risk assessment of heavy metals is critical in controlling and preventing risks of foodborne diseases. Fish can be used as bioindicators for exposure to potential toxic elements (PTEs), which can represent potential risks for humans. The long Iranian coastline and three major fishery regions in the country, including the northern (Caspian Sea) and southern (Persian Gulf and Gulf of Oman) seas as well as inland waters and aquacultures (rivers, dams, wetlands and fish farms) have made Iran a large producer of fish. In the first step of the present study, data collection and report of PTEs in fish from the three fishery regions (2010-2022) were carried out. In the second step, health risks were assessed using Monte Carlo simulation in child and adult consumers. The average concentrations of Cd, Hg and Pb for the northern sea, southern sea, and inland waters and aquacultures were 0.273, 0.249, 1.077; 0.430, 0.423, 1.182; and 1.387, 0.232, 1.703 μg/g per dry weight, respectively. Based on the target hazard quotient results, Hg intake of Iranian children from all the three fishery regions was more than 1, which was alarming. In the adult age group, southern sea fish consumers were at risk of Hg adverse health effects. Moreover, Cd included the highest carcinogenic risk of toxic elements in fish from the three fishery regions of Iran. Estimation of THQ, HI, ILCR and EDI revealed that consumption of fish might induce health complexities for the consumers in Iran. Moreover, Iranians from northern and southern regions of the country consumed further seafood due to the availability of high seafood sources in these regions. Hence, various indices must be used for the risk assessment of general human health. Due to the high risks of carcinogenicity/non-carcinogenicity estimated in the risk assessment, consumption of fish by infants and pregnant women must critically be assessed.

Heavy Metal Pollution in Xinfengjiang River Sediment and the Response of Fish Species Abundance to Heavy Metal Concentrations

Xinfengjiang River, the largest tributary of Dongjiang River, plays a key role in the water supply of Heyuan, Huizhou, Guangzhou and even the Pearl River urban agglomeration. It is crucial to determine the pollution status, potential ecological risk degree of heavy metals in Xinfengjiang river sediment and their influence on the abundance of fish species. In this paper, seven heavy metal concentrations in sediment from the Heyuan section of the Xinfengjiang river were investigated. The order of average concentration was: As > Zn > Pb > Cr > Cu > Cd > Hg. The average concentrations of Cd, Zn and Cu in the upper reaches of the Xinfengjiang Reservoir were significantly higher than those in the reservoir. The mean value order of Igeo was: Cd > Zn > Pb > As > Cu > Cr > Hg. Cd and As had the highest ecological risk index and the greatest threat to the ecological environment. Pearson correlation analysis and principal component analysis demonstrated that the pollution source of heavy metals such as Cu and Cd are much more likely to originate from the mine fields located in the northeast of the sampling sites. In addition, agriculture, electronic industry and domestic sewage also contributed to the concentration of heavy metals in different degrees. Redundancy analysis showed that the abundance of Cypriniformes was negatively correlated with Cu and Cd concentrations, suggesting that mining activities might indirectly affect the abundance of fish species.

Risk Assessment of Hepatocellular Carcinoma with Aflatoxin B1 Exposure in Edible Oils

Contamination of edible oils with aflatoxins (AFs) is a universal issue due to the detrimental effects of aflatoxins on human health and the fact that edible oils are a major source of fungal growth, particularly storage fungi (Aspergillus sp.). The objective of this study was to assess aflatoxin B1 (AFB1) in edible oil used in fried food in order to determine the risk of cancer from AFB1 exposure through cooked food using the FAO/WHO’s and EFSA’s margin of exposure (MOE) quantitative liver cancer risk approaches. Using Mycosep 226 columns and HPLC-FLD, 100 samples of cooking oils (soybean, canola, and sunflower oil) from different food points were analyzed for contamination with aflatoxins. Of all the samples tested, 89% were positive for total aflatoxins and AFB1, with 65% indicating AF concentrations beyond permitted levels. Canola oil was found to contain higher levels of AFB1 and AFs than soybean and sunflower oil. Almost 71 percent of canola oil samples (range of 54.4–281.1 µg/kg) were contaminated with AF levels higher than the proposed limits of the European Union (20 µg/kg). The consumption of canola oil samples used in fried foods had MOE values that were significantly lower as compared to sunflower and soybean oils, indicating that risk reduction is feasible. Additionally, compared to soybean and sunflower oil, canola oil exhibited a greater threat of liver cancer cases linked to AFB1 exposure (17.13 per 100,000 males over 35 and 10.93 per 100,000 females over 35). Using a quantitative liver cancer approach, health risk valuation demonstrated that males and females over the age of 35 are at significant risk of developing liver cancer. The health risk assessment exposed that the males and female over the age of 35 are at considerable risk of liver cancer by using a quantitative liver cancer approach. The innovation of this study lies in the fact that no such study is reported related to liver cancer risk evaluation accompanied with AFB1 exposure from consumed edible oil. As a result, a national strategy must be developed to solve this problem so that edible oil products are subjected to severe regulatory examination.

Distribution and Bioaccumulation of Essential and Toxic Metals in Tissues of Thaila (Catla catla) from a Natural Lake, Pakistan and Its Possible Health Impact on Consumers

Although fish are often recommended as a component of a healthy diet, the environmental accumulation of heavy metals in many fish species has been of considerable concern for those weighing the nutritional health benefits against adverse toxic outcome of excess intake of toxic metals. This study aimed to determine the concentration of essential and toxic metals in the tissues of Catla catla in Mangla Lake and to assess the possible risk to the consumers. Fifty samples of Catla catla were collected from Mangla Lake, Mirpur, Azad Jammu and Kashmir, Pakistan and analyzed for eighteen metals including essential and trace metals. The measured range concentrations (µg/g, wet weight) in muscle tissues, in decreasing order, were: K (955–1632), Ca (550–2081), Na (449–896), Mg (129–312), Zn (61.2–215), Fe (11.6–26.8), Sr (2.60–9.27), Pb (1.72–7.81), Se (1.55–3.55), Co (0.12–4.08), Mn (1.04–4.33), Ni (0.69–3.06), Cu (0.88–2.78), Cr (0.45–1.88), As (0.67–1.58), Cd (0.28–0.56), Hg (0.17–0.57) and Li (0.12–0.38). The metal concentrations found in this study were comparatively higher than those reported in literature. A majority of the metals exhibited higher accumulation in gills compared with those in scales and muscles. Mean levels of Pb, As, Co, Mn, Cd, Cr and Zn in Catla catla muscle were found to be exceeding the international permissible limits for the safe human consumption. The condition factor (K), as an indicator of fish health status, indicated that Catla catla of Mangla Lake are in good health condition. The metal pollution index (MPI) of gills (27.9), scales (12.5) and muscle (7.57) indicated low contamination. Moreover, human health risk was evaluated using estimated weekly intake (EWI) and daily intake (EDI), target hazard quotient (THQ), hazard index (HI) and target cancer risk (TCR). Estimated weekly and daily intake values for As, Cd, Cr, Hg, Ni and Pb were higher than provisional permissible tolerable weekly intake and permissible tolerable daily intake while THQ for As, Cd, Cr, Hg, Pb, Se and Zn was higher than 1. The THQ for As, Hg and Pb was several folds higher than 1, indicative of lifetime non-carcinogenic health risks to the consumers. The hazard index indicated cumulative risk, which greatly increased with increasing fish consumption. Target cancer risk indicated that the people eating the Catla catla from Mangla Lake were exposed to As, Cd, Cr, Ni and Pb with a significant lifetime carcinogenic risk. In summary, consumption of Catla catla from this lake was found to be associated with an increased lifetime risk to the general health of the consumers.

Human health risks associated with consumption of fish contaminated with trace elements from intensive mining activities in a peri-urban region

Worldwide, numerous rural communities and low-income groups depend on fish harvested by subsistence fishers from local rivers and its impoundments as a source of protein. The aim of the present study was to determine the trace element bioaccumulation (As, Cd, Cr, Cu, Ni, Pb, Pt, Zn) in three edible fish species (Cyprinus carpio, Clarias gariepinus, Oreochromis mossambicus) from two impoundments in the Hex River system, South Africa, as well as the chronic health risk these trace elements pose to regular fish consumers. Trace element concentrations in the Hex River are naturally high (geogenic source), however, increased anthropogenic activities, such as intensive platinum mining activities, elevate the already high background concentrations. Concentrations of As, Cr, and Pt in C. carpio and C. gariepinus, as well as Ni and Zn in O. mossambicus were significantly higher in the impacted impoundment as compared to the reference impoundment. Concentrations of Cr and Cu were at both sampling sites the highest in O. mossambicus. From the human health risk assessment, As poses non-carcinogenic (HQ = 2-7) and carcinogenic risks (33-93 out of 10,000 people), while Cr (3-10 out of 10,000 people) and Ni (2-6 out of 10,000 people) pose only carcinogenic risks for the regular consumption of all three fish species from both impoundments, indicating a high probability of adverse human health effects. For As, Cr and Ni, also the sediment concentrations exceeded the levels of concern within the consensus based sediment quality guideline (CBSQG), while Cd, Cu, Ni and Zn exceeded the water quality guideline values. Thus, the CBSQG approach could be a promising tool for predicting human health risk associated with fish consumption. Since the present study only focused on the individual trace element risks, mixed toxicity of these trace elements and possible other pollutants within these fish species may pose an even greater risk to people who consume these fish regularly.

The Occurrence of Lead in Animal Source Foods in Iran in the 2010s Decade: A Systematic Review

Lead is a toxic, non-biodegradable, and accumulative heavy metal released into the environment by natural and anthropogenic activities. Despite health concerns due to the consumption of lead-contaminated foods, no systematic and comprehensive review studies have been published about the lead occurrence in animal source foods in Iran. The present study aimed to review the papers investigating the Pb contamination in animal-based food groups (including meat, fish, milk and dairy products, egg and honey) in Iran. A comprehensive search was performed with selected keywords in databases of Scopus, Web of science, and Magiran to find articles that had been published from January 2010 to December 2019. Of 371 identified articles on Pb contaminations in foods, 60 articles were selected using PRISMA. The lead concentrations were higher than the maximum recommended limits in 3 of 9 studies on meat and meat products, 12 of 26 studies on fish and canned fish, and 5 of 18 studies on milk and dairy products. However, the Pb contamination observed in studies on honey and egg was not comparable due to the lack of national and international standards. These results represent the importance of environmental monitoring and assessment for reducing exposure of animals to Pb, resulting in an improvement of food safety.

Effects of heavy metal contamination released by petrochemical plants on marine life and water quality of coastal areas

The present study attempts to assess the threat of water contamination in Persian Gulf by heavy metals (Fe, Cr, Pb, Cu, Zn, Cd, Se, and Ni) and its subsequent effects on five fish species including Scomberomorus guttatus (S. guttatus), Lethrinus nebulosus (L. nebulosus), Brachirus orientalis (B. orientalis), Pomadasys kaakan (P. kaakan), and Scomberomorus commerson (S. commerson). Water and fish samples from fourteen monitoring stations were obtained to determine the concentrations of contaminants in water and fish. Heavy metal pollution index (HMPI) and non-carcinogenic hazard quotient (NHQI) were employed to evaluate contamination level in water and fish muscle. The Kriging geostatistical method was employed to determine the spatial distribution of different heavy metals around petrochemical plants. The highest NHQI values for P. kaakan and B. orientalis species were 1.036 and 1.046, respectively. In both cases, the NHQI values were higher than the maximum allowable value of 1, indicating that both fish species were on the verge of contamination by heavy metals, which in turn makes the consumption of these fish highly hazardous to human health. The lowest NHQI value was observed in S. commerson species at a value of 0.394, indicating its harmlessness to human health. Overall, fish species living within the top 5 m of the water column (S. commerson and S. guttatus) were found to be less contaminated by heavy metals compared to species dwelling near the seafloor (P. kaakan and B. orientalis). Results also indicated the pollution absorption rate in S. commerson and S. guttatus were 0.45 and 3.4 mg/kg-year, while the corresponding values for the B. orientalis and L. nebulosus species were 6 and 2 mg/kg-year, respectively. P. kaakan species showed a pollution absorption rate of 3.2 mg/kg-year. High heavy metal concentrations of 4.8, 10, 9.8, 5.2, 9.4, and 6.7 mg/L were obtained for Cr, Zn, Pb, Ni, Fe, Cu, and Cd, respectively, in water samples obtained from stations nearby petrochemical plants. The HMPI index for the most contaminated stations was ten times that of the maximum allowable limit. Given the intense activity of oil, gas, and petrochemical plants in the Persian Gulf, defining safe fishing areas by management practices similar to contamination zoning maps presented in this study can substantially protect the public health from heavy metal contamination.

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

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

Study of speciation and spatial variation of pollutants in Anzali Wetland (Iran) using linear regression, Kriging and multivariate analysis

Multivariate statistical techniques and geostatistical methods are among the important tools used in surface water quality management. They are widely used in interpreting data, identifying the pollution sources, understanding the spatial variation of parameters, and determining the places of monitoring stations. Therefore, in this study, spatial variation of water quality and pollutants in the Anzali Wetland water (Iran) was evaluated using multivariate statistical and Kriging methods. The values of different water quality parameters measured in six stations in the wetland water were subjected to cluster analysis (CA) and principal component analysis (PCA). Cluster analysis reduced the number of stations from six to four. The results of PCA showed that industrial and agricultural pollution sources could be responsible for the Anzali Wetland water quality. Then, the spatial variation maps of the PCA scores were generated using Kriging geostatistical method in the geographical information system (GIS) to investigate the pollution sources affecting the wetland parts. These maps illustrated that a great part of the wetland body was under the effect of agricultural sources, while the industrial sources affected the outlet and central parts. Finally, a comparison between two models (multiple linear regression (MLR) and Kriging) was made to assess their ability in predicting water quality parameters in the study area. The results showed the improvement of prediction using MLR, which was by 25%-97%, compared with Kriging. The results of the present study can be effectively used in the planning and implementation of future monitoring networks in the Anzali Wetland and other similar aquatic systems.

Bioaccumulation of heavy metals in some commercially important fishes from a tropical river estuary suggests higher potential health risk in children than adults

The Karnaphuli River estuary, located in southeast coast of Bangladesh, is largely exposed to heavy metal contamination as it receives a huge amount of untreated industrial effluents from the Chottagram City. This study aimed to assess the concentrations of five heavy metals (As, Pb, Cd, Cr and Cu) and their bioaccumulation status in six commercially important fishes, and also to evaluate the potential human health risk for local consumers. The hierarchy of the measured concentration level (mg/kg) of the metals was as follows: Pb (13.88) > Cu (12.10) > As (4.89) > Cr (3.36) > Cd (0.39). The Fulton's condition factor denoted that fishes were in better 'condition' and most of the species were in positive allometric growth. The bioaccumulation factors (BAFs) of the contaminants observed in the species were in the following orders: Cu (1971.42) > As (1042.93) > Pb (913.66) > Cr (864.99) > Cd (252.03), and among the specimens, demersal fish, Apocryptes bato appeared to be the most bioaccumulative organism. Estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI) and carcinogenic risk (CR) assessed for potential human health risk implications suggest that the values were within the acceptable threshold for both adults and children. However, calculated CR values indicated that both age groups were not far from the risk, and HI values demonstrated that children were nearly 6 times more susceptible to non-carcinogenic and carcinogenic health effects than adults.

Bioaccumulation and heavy metal concentration in tissues of some commercial fishes from the Meghna River Estuary in Bangladesh and human health implications

Despite the beneficial aspect of aquatic food's consumption, bioaccumulation of toxic metals in fish can enhance the health risk for the consumers. Heavy metals were measured from editable tissues of some commercial fish species like Latis calcarifer, Silonia silondia, Clupisoma garua, Planiliza subviridis, Otolithoides pama, Tenulosa ilisa, Rhinomugil corsula, and Aila coila in the Meghna river estuary in Noakhali district. Heavy metals such as As, Pb, Cd, Cu, and Cr were detected by ICP-MS, which were significantly different (p ≤ 0.01), and the hierarchy of all mean concentrations were: Cu (5.14 mg/kg) > Pb (3.79 mg/kg) > As (1.08 mg/kg) > Cr (0.78 mg/kg) > Cd (0.12 mg/kg). The mean concentration of Cu (6.62 mg/kg) imparted to the maximum level in L. calcarifer, which slightly exceeded the Bangladesh food safety guideline. The mean BAFs of the contaminants were found as: Pb (1042.29) > Cr (1036.47) > As (934.84) > Cd (832.77) > Cu (772). Further, L. calcarifer, S. silondia, C. garua, and P. subviridis showed the bioaccumulative status. To assess the health risk effects, estimated daily intake (EDI), target hazard quotient (THQ) and carcinogenic risk (CR) were conducted. THQs for both adult and children consumers were <1, indicating that, consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, CR for all the consumers was found in the acceptable range (10^-6 to 10^-4).

Prevalence and probabilistic health risk assessment of aflatoxins B1, B2, G1, and G2 in Iranian edible oils

The prevalence of aflatoxins (AFs) B₁, B₂, G₁, and G₂ in Iranian edible oils were assessed by immunoaffinity column cleanup and HPLC equipped with a fluorescence detector (HPLC-FLD). Ninety-seven samples including sunflower, canola, refined olive, unrefined olive, frying, and blend oils were collected from eight provinces (n = 15 samples of refined olive oil, n = 15 samples of unrefined olive oil, n = 15 samples of sunflower oil, n = 15 samples of canola oil, n = 17 samples of frying oil, and n = 20 samples of blend oil). Also, cancer risk of aflatoxins in the adults and children due to ingestion of edible oils was estimated via margin of exposure (MOE) estimation in the Monte Carlo simulation (MCS) model. Considering the limit of detection (LOD) of the current study, two unrefined olive oil samples from Zanjan Province were contaminated with AFB₂ in the concentrations of 0.2 and 0.4 ng/g while other samples were free from AFB₁, AFB₂, AFG₁, and AFG₂. This study revealed that about 98% of the collected samples were free from AFs and the concentrations of AFs in the polluted samples were within the standard range suggested by European Commission regulation (20 μg/kg). However, health risk assessment indicated that both adult and children in the Zanjan Province are at considerable liver cancer risk (percentile 95% of MOE < 10,000 value). Therefore, national plan to address this issue and strict inspection of edible oil products by the regulatory bodies are suggested.

Contamination and Prevalence of Histamine in Canned Tuna from Iran: A Systematic Review, Meta-Analysis, and Health Risk Assessment

Histamine is one of the most important health issues associated with consumption of canned tuna because of possible allergic and anaphylactic reactions in consumers. Although the concentrations of histamine in tuna in Iran have been investigated in several studies, definitive conclusions are elusive. This study was undertaken as a systematic review and meta-analysis of the concentration and prevalence of histamine in Iranian canned tuna, and the related health risk was assessed. An extensive search of articles in the databases Scopus, PubMed, and Scientific Information Database resulted in 11 articles and a total of 693 samples for inclusion in this review. The minimum and maximum concentrations of histamine were determined as 8.59 ± 14.24 and 160.52 ± 87.59 mg kg⁻¹, respectively. The mean concentration was calculated as 77.86 mg kg⁻¹ (95% confidence interval [CI], 47.51 to 108.21 mg kg⁻¹), which was lower than the 200 mg kg⁻¹ recommended limit by the U.S. Food and Drug Administration (FDA). The mean prevalence of histamine was 9.19% (95%; CI, 6.88 to 11.5%). The 95% value of the target hazard quotient for adult consumers was calculated as 0.10. In all studies performed in Iran, the concentration of histamine in canned tuna was lower than FDA standard. Health risk assessment indicated low histamine risk (target hazard quotient < 1) for adults in Iran from consumption of canned tuna.