Human health risk from organ-specific accumulation of toxic metals and response of antioxidants in edible fish species from Chenab River, Pakistan

Heavy metals contamination of seafood from the crude oil-impacted Niger Delta Region of Nigeria: A systematic review and meta-analysis

This study aims at computing the pooled mean estimate (PME) and health risks of heavy metals in seafood obtained from the Niger Delta Region of Nigeria (NDRN), using data from existing literatures. Pubmed, Scopus and Google Scholar were searched to retrieve articles that investigated the heavy metal contents of edible seafood from the NDRN. Search hits were screened against predetermined criteria following which relevant data were extracted from eligible articles. The PME for each metal was computed by performing a maximum likelihood random effect model meta-analysis using the R Studio Software. Outcome from the meta-analysis involving 58 studies and a total of 2983 seafood samples revealed the following PMEs (mg/kg dry wt seafood) for the investigated heavy metals: As (0.777), Cd (0.985), Co (4.039), Cr (2.26), Cu (11.45), Fe (143.39), Hg (0.0058), Mn (13.56), Ni (5.26), Pb (4.35), and Zn (29.32). The health risk assessment suggests that seafood from this region poses considerable carcinogenic and non-carcinogenic risks to human consumers. Our finding calls for urgent actions aimed at identifying and eliminating point sources of heavy metals pollution of the NDRN marine environment. Inhabitants of NDRN are encouraged to reduce seafood consumption while diversifying their protein sources to include non-seafood options.

Modeling of Cadmium Bioaccumulation Dynamics in Channa punctata (Bloch, 1793) of Dankuni Wetland Ecosystem and Assessment of Risk to Human Health

Contamination of freshwater wetlands with toxic heavy metals and metalloids is a significant public health concern. Cadmium (Cd) is one of the most common heavy metals affecting water bodies and fish. In the Dankuni wetland (DW) ecosystem in India, variations in Cd concentration from the aquatic system to different fish tissues have been investigated. Channa punctata is an easily accessible fish with a high nutritional value, and offers a good economic return for the fishermen of West Bengal. A dynamic model was constructed considering the importance of the Cd concentration in the water of the wetland system and different fish tissues. A sensitivity analysis was performed to assess the valuable contribution of different parameters that determine the dynamics of Cd concentration in a wetland aquatic environment. The observed data is used to verify the model simulation performance. To predict the effects of Cd on humans, a survey of fish consumers was conducted around DW. Individuals living near DW, on low income (<5,000 INR) and over the age of fifty, were at high risk of Cd contamination. Their average daily intake rate was quite high (2.48×10^-5 mg kg^-1 day^-1) and the hazard quotient calculated for these individuals was also high (0.024). People over age of 50 years had renal, cardiovascular, and osteological diseases with disease percentages of 56%, 46%, and 45%, respectively. Data on Cd-related health problems were collected from Cd-associated and non-Cd-associated individuals residing in the periphery of DW. The system-sensitive parameter was the rate of Cd entry into the water system (C Inp rt). If the Cd level is checked at the entrance of the reservoir by management policy; the risk of Cd contamination to human may be minimized in this area.

Comparative assessment of human health risk associated with heavy metals bioaccumulation in fish species (Barbus grypus and Tenualosa ilisha) from the Karoon River, Iran: Elucidating the role of habitat and feeding habits

Concentrations of Cd, Ni, and Pb were measured in the liver and muscle tissues of benthic omnivorous (Barbus grypus) and pelagic herbivorous (Tenualosa ilisha) fish collected from two sampling sites along the Karoon River, Khuzestan Province, southwest of Iran. Potential human health risks were evaluated by measuring the estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TR). The results highlight the important role of habitat and feeding habits in the uptake of HMs by the two species. The EDI for all HMs exceeded the oral reference doses (RfDo) provided by the USEPA, indicating the two fish species are not entirely safe for human consumption. The THQ values were within the permissible limit (< 1), while HI values (> 1) showed there was non-carcinogenic risk for consumers. The TR values for Pb were within the acceptable range (1.00E-06-1.00E-04) for both species.

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.

Accumulation of Trace Metals in Indigenous Fish Species from the Old Brahmaputra River in Bangladesh and Human Health Risk Implications

In this study, accumulation of the top six most toxic trace metals (Arsenic (As), Cadmium (Cd), Chromium (Cr), Mercury (Hg), Nickel (Ni) and Lead (Pb)) were assessed in six indigenous fish species (Barilius barila, Salmostoma acinaces, Gudusia chapra, Labeo bata, Corica soborna, and Sperata aor) collected from the Old Brahmaputra River in Bangladesh. Human health risk associated with these fish consumption was also evaluated. Metals were analyzed in whole body of fish by an atomic absorption spectrometer (AAS). Mean concentrations of metals (μg/g, wet weight) were in the range of As (< 0.02-0.278), Cd (< 0.002-0.005), Cr (0.239-0.761), Hg (0.008-0.057), Ni (< 0.02-0.044), and Pb (< 0.01-0.038). The metal contents varied significantly among the fishes regarding their feeding habits and living habitats. Concentrations of As, Cr, Hg, and Pb were significantly higher in omnivorous species, whereas the benthopelagic species showed significantly higher accumulation of As (p < 0.05). The target hazard quotient (THQ) for noncarcinogenic risk and target cancer risk (TR) for carcinogenic risk were calculated to estimate the probabilities of experiencing these adverse health effects for the fish consumers. Metal-specific THQ values were all below 1 indicating no potential human health risk. Nonetheless, the hazard index (HI) values to estimate the effects from exposure to all metals collectively elucidated chronic noncarcinogenic health risk particularly from G. chapra consumption. The TR values revealed that there was carcinogenic risk from exposure to As through consumption of the fish. This study finally suggests a systematic and continuous monitoring of trace metal contamination in fishes from the river to ensure the fitness of this food item regarding the safety for human health.

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

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

Melatonin protects bone against cadmium-induced toxicity via activation of Wnt/β-catenin signaling pathway

Among heavy metals, cadmium (Cd) is one of the most toxic for health due to it accumulation in several tissues including bone. Since melatonin (MLT) favors new bone formation through several pathways including Wnt/β-catenin, here we assessed whether MLT has a protective role against Cd induced toxicity in the rat bone tissue. Adult male Wistar rats receiving 50 mg CdCl₂/L and/or 3 mg/L MLT were used and were sacrificed 30 days after the treatment. Femurs and plasma were collected and analyzed by various biochemicals, molecular and histological investigation. The results showed that Cd exposure induced bone disorder characterized by histopathological alterations, a decreased alkaline phosphatase activity and plasmatic concentration of osteocalcin. Moreover, also the expression levels of some osteogenic-related genes (Runx2, Ocn and Alp) were down-regulated after Cd treatment. Since mechanistically Cd toxicity reduced the Kinase activity of GSK3β and protein levels of Wnt3a and β-catenin, we observed that MLT administration significantly ameliorated the toxic effects induced by the metal. Our findings provide clues about a potential protective effect of MLT against Cd-induced bone metabolism destruction and that the protection was partially mediated via the Wnt/β-catenin signaling pathway.

Ecological and health risk assessment of potentially toxic elements in the major rivers of Pakistan: General population vs. Fishermen

Large amounts of potentially toxic elements (PTEs) have, and continue to be, released into the freshwater ecosystems of Pakistan. However, there is limited information available on the ecological risk of PTEs from sediments and fish consumption, for both the general population and fishermen, at the national scale in Pakistan. In this study, water, sediments and fish samples were collected from major rivers (Chenab, Upper Indus, Lower Indus and Kabul) across Pakistan and analyzed through Inductively Coupled Plasma Mass Spectrometer (ICP-MS), Inductively Coupled Plasma Atomic Emission Spectroscopy ICP-AES and Atomic Fluorescence Spectrometry (AFS), respectively. Ecological risk analysis of sediments revealed that Cd posed a high ecological risk in the Upper Indus and Chenab, a considerable risk in the Lower Indus, and moderate risk in the Kabul. The target hazard quotient of As through fish tissue consumption exceeded safety levels for fishermen at all the rivers, where Cd exceeded at Upper Indus and Chenab, and Pb for Chenab fishermen only. For the general population, PTE ingestion through fish tissues was within the safety limits at all rivers. Meanwhile, the total target hazard quotient in all three rivers exceeded the safety limit, representing a high risk for the fishermen of Pakistan. The results show that ecological risk and target hazard quotient assessment not only provides valuable information for future research in terms of PTE contamination in the major rivers of Pakistan, but also all the metal pollutants from rivers finally reach to Arabian Sea, therefore might pose a risk to marine ecosystem at national and international scale.

Human exposure to trace metals and arsenic via consumption of fish from river Chenab, Pakistan and associated health risks

This study provided the first hand data of trace elements into fish muscles (N = 65) collected from river Chenab in Pakistan during 2013, using inductively coupled plasma mass spectrometry (ICP-MS). We monitored the health risk associated with consumption of contaminated fish of river Chenab, by the local population. The mean concentrations (μg/g, wet weight), in descending order were: Zn (35.5-54.4), Cu (1.38-4.57), Mn (2.43-4.5), As (0.23-1.21), Cr (0.21-0.67), Ni (0.14-0.34), Pb (0.14-0.31), Co (0.09-0.12), Cd (0.07-0.12) with higher concentration to be observed in the herbivore fish species (i.e., Cirrhinus reba and Catla catla). The levels of trace elements in different fish species found in this study were compared with similar data worldwide, and with the international standards for consumption. The concentration (μg/g) of arsenic in many cases (>65%) exceeded the FAO/WHO expert committee on food additives permissible limits. From the human health point of view, this study highlights that the local inhabitants, (i.e., fisher folk communities and population frequently consuming fish at about 100 g/day) along the river Chenab are exposed chronically to arsenic pollution with carcinogenic (10^-4 to 10^-6) and non-carcinogenic (THQ>1) risks, especially from the intake of Cirrhinus reba.

Oral exposure of mice to cadmium (II), chromium (VI) and their mixture induce oxidative- and endoplasmic reticulum-stress mediated apoptosis in the livers

Health concerns regarding the environmental heavy metals in wildlife and humans have increased in recent years. We evaluated the effects of exposure of mice to low doses of cadmium (Cd), chromium (Cr) and their mixtures on oxidative- and ER-stress. Male adult mice were orally exposed to Cd (0.5 and 2 mg kg(-1) ), Cr (1 and 4 mg kg(-1) ) and binary Cd+Cr mixtures (0.25 + 05 and 1 + 2 mg kg(-1) ) daily for 36 days. We observed that the bioaccumulation of Cd and Cr in the liver in a dose-dependent manner, and the Cd and Cr contents in the 2 mg kg(-1) Cd and 4 mg kg(-1) Cr treated groups reached 2.43 and 3.46 µg g(-1) liver weight. In addition, treatments with 2 mg kg(-1) Cd, 4 mg kg(-1) Cr or their mixture (1 + 2 mg kg(-1) ) significantly decreased body and liver weights, increased the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and activities of catalase (CAT) and glutathione peroxidase (GPX) in the liver. Moreover, Cd and Cr exposures also elevated the transcription of the oxidative- and endoplasmic reticulum (ER)-stress related genes including Cat, Gpx, heme oxygenase 1 (Ho-1), regulated protein 78 (Grp78), activating transcription factor 6 (Atf6) and proaoptotic CCAAT/-enhancer-binding protein homologous protein (Chop) in a dose dependent manner in the liver. And hepatic cytochrome c levels increased in all Cd, Cr or their mixture treated groups. Furthermore, the transcriptional status and the activities of Caspase 9 and Caspase 3 were increased significantly in the liver when exposed to high doses of Cd, Cr or their mixture. These results suggested that a long period exposure of mice to Cd or Cr has the potential to elicit oxidative- and ER-stress mediated apoptosis in their livers. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 693-705, 2016.

Subchronic exposure to static magnetic field differently affects zinc and copper content in murine organs

PURPOSE

Static magnetic fields (SMF) have been widely used in research, medicine and industry. Since zinc and copper play an important role in biological systems, we studied the effects of the subchronic continuous SMF exposure on their distribution in murine tissues.

MATERIALS AND METHODS

For 30 days, mice were exposed to inhomogeneous, vertical, downward or upward oriented SMF of 1 mT averaged intensity with spatial gradient in vertical direction.

RESULTS

SMF decreased the amount of copper and zinc in liver. In brain, zinc levels were increased and copper levels were decreased. In spleen, zinc content was reduced, while copper amount remained unchanged.

CONCLUSIONS

Subchronic exposure to SMF differently affected copper and zinc content in examined organs, and the changes were more pronounced for the downward oriented field. The outcome could be attributed to the protective, rather than the harmful effect of SMF.

Genotoxicity and cytotoxicity of copper oxychloride in cultured human lymphocytes using cytogenetic and molecular tests

The genotoxicity of copper oxychloride was investigated in human lymphocytes using chromosome aberration (CA) and micronucleus (MN) tests and the randomly amplified polymorphic DNA-polymerase chain reaction technique. The lymphocytes were treated with 3, 6, and 12 µg/mL of copper oxychloride for 24 and 48 h. Copper oxychloride increased CA and abnormal cells in a dose-dependent manner. The frequency of MN and micronucleated binuclear cells also increased at all concentrations and treatment periods. However, copper oxychloride cytotoxicity, observed through lower mitotic and nuclear division index, was significantly lower only at the higher concentrations (6 and 12 µg/mL). Copper oxychloride increased the polymorphic bands and decreased genomic template stability. In conclusion, in this study it was confirmed that copper oxychloride has genotoxic potential for human lymphocytes in vitro. Additionally, caution is advised for its use as a fungicide, because it may increase the risk of exposure through the food chain.

Hepatic oxidative stress and inflammatory responses with cadmium exposure in male mice

Cadmium (Cd), a non-essential heavy metal, is one of the major environmental contaminants with grave toxicological consequences globally. In the present study, the effects of Cd on hepatic oxidative stress and inflammatory responses in mice were evaluated. Male adult mice were orally exposed to 3, 10 and 30mg/L CdCl2 supplied in the drinking water for 7 and 21 days. Histopathological changes and the alterations of the main parameters related to oxidative stress and inflammatory responses in the liver were observed. Hepatic malondialdehyde (MDA) contents increased significantly after treatment with 30mg/L CdCl2 for 21 days, and the contents of glutathione (GSH) increased significantly in both 10 and 30mg/L CdCl2 treated groups. The hepatic activities of glutathione peroxidase (GPX), catalase (CAT) and glutathione S-transferase (GST) increased significantly after the treatment with 30mg/L CdCl2 for 21 days. In accordance with the enzyme activities, the transcription status of hepatic superoxide dismutase 1 (Sod1), superoxide dismutase 2 (Sod2), Cat, Gpx, Gstα1, glutathione synthetase (Gss), glutathione reductase (Gr) and heme oxygenase 1 (Ho1) were also increased by high dose (30mg/L) or long period (21 days) exposure. In addition, the serum levels of tumor necrosis factor α (TNFα), interleukin 6 (IL6) and interleukin 1β (IL1β) increased significantly in the groups treated with 30mg/L CdCl2 for 21 days. And the genes of TNFα, IL6, interleukin 1α (IL1α), inducible nitric oxide synthase (iNOS) and interferon γ (IFNγ) were also increased in the liver of mice when exposed to relative high dose of CdCl2 for 7 or 21 days. Taken together, the results of this study suggested that the exposure to Cd had the potential to induce immunotoxicity accompanied with oxidative stress in the liver of mice.