Heavy metal concentrations in marine fishes collected from fish culture sites in Hong Kong

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.

A novel approach to assess temporal baseline levels of trace metal contamination in the mussel M. galloprovincialis in the Mediterranean, Marmara and Black Seas

This study reports, for the first time, the baseline levels for fifteen trace metals in M. galloprovincialis tissue from around the Mediterranean, Marmara and Black Seas. The environmental quality in the surrounding seawater was assessed i.e., a mussel farm was investigated by using CF and DC indices, and the water quality was qualified as good for the aquacultural activities. A strong Cu-regulation in the transplanted mussels was observed and it ranged between 3.20 and 3.60 μg/g d.w. The highest bioavailability and bioconcentration of the particulate Fe fraction could present a health risk to consumers with a low risk level (1 < THQ < 9.9). Cr is considered the limiting metal for mussel consumption (< 2 kg/day). The metal contamination gradient was assessed using TEPI and TESVI indices that identified seven reference stations on the large scale and revealed that Cd is the most investigated metal in the literature databases, and found that Pb was the most bioavailable contaminant in the areas examined.

Impacts of the Residual Trace Metals of Aquaculture in Net Cages on the Quality of Sediment

Anthropogenic pollution by trace metals in aquatic environments in semiarid zones is a critical area of investigation. The objective of this study was to investigate the concentration and spatial distribution of trace metals in surface sediments in the Rosário reservoir, which is affected by the intensive aquaculture of Tilápia-do-Nilo (Oreochromis niloticus). Sediment samples were collected in three different areas, postculture (PCTV), cultivation (CTV) and control (CTRL) in the dry season in 2019. The granulometric composition, organic matter and concentrations of Fe, Mn, Zn, Cu, Cr, Cd, Pb and Ni metals were determined. Multivariate statistics were used. Geochemical and ecotoxicological indices and a comparison with sediment quality guidelines (SQG) were used. The sediment was characterized by silty clay loam with an average organic matter of 18.76 ± 4.27. The analytical merit figures demonstrated accuracy (metal recoveries in certified standards) between 89 to 99% and high precision (RSD < 5%). The concentration ranges for the metals were Fe: 0.11-0.85 (%), Mn: 14.46-86.91, Zn: 2.6-220.56, Cu: 26.89-98.75, Cr: 60.18-76.06, Cd: 0.38-0.59, Pb: 18.13-43.13, and Ni: 34.4-46.75, all in (mg/kg^-1). The highest concentration values were found in the CTV areas (Fe: 40 ± 0.22, Mn: 66.48 ± 19.11, Zn: 114.83 ± 59.75 and Cr: 70.85 ± 2.62) and PCTV (Cd: 0.53 ± 0.04, Cu: 71.83 ± 21.20, Pb: 33.71 ± 4.34 and Ni: 44.60 ± 1.79). Pearson's correlation, hierarchical cluster analysis and principal component analysis confirmed the influence of fish farming on metals. Only Ni presented concentration values higher than the reference value established in the SQG. Thus, considering the probable geochemical and ecotoxicological effects, they comprise the two lowest levels of impact.

Metal Bioaccumulation and Potential Health Risk Assessment in Different Tissues of Three Commercial Fish Species (Merluccius merluccius, Mullus barbatus, and Pagellus erythrinus) from Edremit Bay (Aegean Sea), Turkey

Metal levels and potential health risk assessment in muscle, liver, and gills of three fish species (Merluccius merluccius, Mullus barbatus, and Pagellus erythrinus) from the Edremit Bay were investigated in spring and autumn 2015. Metal concentrations (Hg, Cd, Pb, Cr, Cu, Zn, Mn, and Fe), metal pollution index, and bioaccumulation factors in P. erythrinus were observed to be generally higher than those in M. barbatus and M. merluccius. Tissue was the main factor that might be responsible from the variations of metals in fish species according to ANOVA and PCA. Hg concentrations in M. barbatus and P. erythrinus were greater than threshold limits defined by international authorities; however, no carcinogenic risks were found for Cd and Pb levels. According to the results, the bay has been negatively influenced by human activities, and further research on monitoring of the biota and sediments is recommended for Edremit Bay and similar coastal areas under human pressure.

Heavy Metals in the Fish Tenualosa ilisha Hamilton, 1822 in the Padma-Meghna River Confluence: Potential Risks to Public Health

Hilsa shad (Tenulosa ilisha) is Bangladesh's most important single-species fishery that contributes to 11% of total catch and employment for millions of people. However, heavy metals (HMs) toxicity in the edible organs of T. ilisha and their plausible public health threats have received weak attention. To provide insights on this issue, we determined, using ICP-MS, the concentration of Zn, Cu, Cr (VI), Pb, and Cd in the edible organs of five different sizes of T. ilisha and the surface water collected from the Padma-Meghna River confluence, Chandpur (Bangladesh). Multivariate analysis indicated that T. ilisha gills and liver contained higher HMs than muscle, and the surface water was below the safety limits. The study revealed that only Cr crossed the safety limits and bioaccumulated in the smaller-sized gills and liver. To assess the public health risks, target hazard quotient (THQ), total THQ (TTHQ) and carcinogenic (CR) risks were calculated. Only Cr imposed non-carcinogenic risks to consumers, while TTHQ showed higher chronic health risks. There was no CR risk measured for consumers, except for the largest-sized gills for children. Randomly positive relations between HMs and sizes were found; whereas, consistently positive relations were found among the tissue types. The outcomes of our study may aid policymakers in managing pollutants, especially the Cr sources in the greater Chandpur regions.

Dietary nutrients and health risks from exposure to some heavy metals through the consumption of the farmed common carp (CYPRINUS CARPIO)

Common carp (Cyprinus carpio) is one of the most important cultured fish species in Poland. The aims of our study were to determine the concentration of essential minerals in the muscle tissue of carp obtained from a pond culture and to compare the content of these minerals with the physiological norms of nutrition for the Polish population, Recommended Dietary Allowances (RDA), and Estimated Average Requirements (EAR). The non-carcinogenic and carcinogenic risk by assessment of the Estimated target hazard quotients (THQ), total target hazard quotients (ΣTHQ), and carcinogenic risk were also studied. The muscle tissue of the carp was rich in macroelements. The pattern significance gradation of element concentrations was as follows: Na > K > Ca > P > Mg > Al > Zn > Fe > Cu > Mn > Cr > Se > Co. The concentration of toxic heavy metals in the samples was lower than the maximum allowable level of metals in food products. The risk of consumption of toxicants by an adult at a daily intake of 100 g of fish was 1.45% for Pb, 0.1% for Hg, 0.02% for Cd, and 0.02% for As, compared to the allowable daily intake for each toxicant. The value of the target hazard quotients of each metal was less than 1, indicating that the intake of a single metal through the consumption of carp meat does not pose a considerable health hazard. The total value of the target hazard quotients was also less than 1, indicating the safety of the combined effects of the chemicals. The major risk contributor was Pb with 82.9%, followed by Hg (9.38%), As (6.43%), and Cd (1.29%).

Investigation of the Metal Pollution Sources in Lake Mogan, Ankara, Turkey

It is important to investigate the monthly level of trace metals in freshwater systems to assess environmental health. This information can be used to support effective management and control of natural areas in regard to the introduction and bioavailability of chemicals in the aquatic environment. We aimed to determine monthly changes in the levels of aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), mercury (Hg), zinc (Zn), nickel (Ni), and selenium (Se) in water, sediment, and fish samples from Lake Mogan. Five different stations were established in Lake Mogan. Water and sediment samples as well as muscle, liver, kidney, gill, and brain tissues from fish were obtained from these stations every month for 1 year. All analyses were conducted with ICP-OES. In descending order of intensity, the metals identified in the water samples were Fe, Cu, Cr, Zn, Pb, Ni, As, Se, and Hg; those identified in the sediment samples were Fe, Zn, Cu, Ni, Se, Pb, Cr, As, Al, Cd, and Hg; and those identified in fish tissues were Se, Fe, Zn, Cr, Al, Pb, Cu, Ni, As, Hg, and Cd. The most polluted station was located where waste from restaurants and tea gardens were dumped. The level of waste, and thus the level of pollution, was especially high in August. It is concluded that the metals that accumulate in water, sediment, and fish in Lake Mogan originate from anthropogenic activities.

Seasonal Occurrence of Ibuprofen in Sediment, Water, and Biota in River Owena and Ogbese, and its Ecological Risk Assessment

The volume of pharmaceuticals discharged into the environment increases daily as a consequence of human life. In the present study, the seasonal variation of ibuprofen in sediment, biota, water, and their exposure risk were investigated in River Owena and Ogbese, Nigeria. The high-performance liquid chromatography coupled to a mass spectrometer (HPLC-MS/MS) was used to analyze the samples after clean up and pre-concentration by solid-phase extraction. The mean concentration of IBU in the samples spanned a range of 1.75 - 2.75 μg/g in sediment, 0.01 – 15.00 μg/g in fish, and 0.00002 – 0.005 μg/ml in water. The measurement of IBU in the sediment and water was significantly elevated in the dry season than the wet season, whereas the opposite was the case in biota. There was a significant interaction between season, media, and rivers with respect to IBU occurrence in the sampled rivers. The calculated bio-water accumulation factor (BWAF) was as high as 750,000 μg/g in fish, proving IBU is extremely bio-accumulative. The ecotoxicological risk assessment for average and worst possible outcome showed that the risk quotient (RQ) for IBU present in the water was sufficient to cause toxicity to fish in both freshwater bodies. The potential bioavailability of IBU to aquatic fauna for prolonged periods spanning several months can result in its circling back into the food web afterward. The baseline info provided by this study in these freshwaters may provide valuable information for the implementation of safety limits for the management of IBU influx into the environment.

Comparative study of raw and cooked farmed sea bass (Lates calcarifer) in relation to metal content and its estimated human health risk

Metallic contamination in seafood, especially fish, has been of increasing concern to human health. Moreover, with increasing dependency on farmed fish for fish resources, the metallic contamination in them is still questionable. This study aimed to investigate the effects of cooking (steaming) on heavy metal concentration in farmed fish and to estimate its potential human health risk. Farmed sea basses (Lates calcarifer) from Setiu Lagoon were used to study the difference in metal uptake through human consumption of raw and cooked (steamed) fish samples. Selected heavy metals, namely copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb), were measured using ICP-MS following Teflon bomb closed digestion of the fish samples. Cooking of the fish muscle by steaming was applied to investigate if cooking changes the concentration of heavy metals. Mercury and As were found accumulated more notably in the fish muscle, though only Hg was found to show significant (p > 0.05) increase when L. calcarifer is cooked. The amount of As in the fish muscle throughout its growth can be potentially harmful to humans, with the highest averaged concentration at 3.29 ± 0.65 mg/kg dw. above the standard set by the Malaysian Food Regulation (1985) of >1 mg/kg. All the other heavy metals were at relatively safe concentrations well below the standard set by both national and international guidelines. The PTWI per individual of L. calcarifer for As was at 0.84 mg/kg bw., which indicated that the amount of this fish safe for consumption without any adverse effect is 170 g/week. Therefore, long-term intake of these fish may pose a risk to human health due to the relatively higher Hg and As concentration found in these fishes.

Comparison of elemental composition in two wild and cultured marine fish and potential risks to human health

Among all available species, fish are a powerful model for risk-benefit assessments to study the effects of contaminants on human health. Gilthead seabream (Sparus aurata, Linnaeus 1758) and european seabass (Dicentrarchus labrax, Linnaeus 1758) are two species of great economic importance, representing very large production volumes in the Mediterranean. The objective of this study is (1) to analyze the concentrations of Trace Elements (TE) between wild and cultured seabream and seabass specimens, (2) to compare the determined concentrations with other studies, and (3) to increase the data about the potential risks to human health. Our results point to significant intra- and interspecies-specific differences between wild and cultured fish for several trace elements. Several strong and moderate inter-elemental correlations in fish muscle were observed through correlation analysis. In our study, the mean levels of trace elements were still below the standard safety values for fish intended for human consumption. The same results were reached for all the parameters analyzed (international legal limits, estimated weekly intake, provisional tolerable weekly intake, target hazard quotient, target cancer risk), with trace element levels in fish below those that could pose a risk to human health. Consequently, these fish can be considered safe for human consumption. A better understanding of the levels of trace elements in fish would also better inform consumers about the potential risks of exposure to contaminants.

Bioaccumulation of heavy metals in maricultured fish, Lates calcarifer (Barramudi), Lutjanus campechanus (red snapper) and Lutjanus griseus (grey snapper)

Mariculture fish contains a rich source of protein, but some species may bioaccumulate high levels of heavy metals, making them unsafe for consumption. This study aims to identify heavy metal concentration in Lates calcarifer (Barramudi), Lutjanus campechanus (Red snapper) and Lutjanus griseus (Grey snapper). Three species of mariculture fish, namely, L. calcarifer, L. campechanus and L. griseus were collected for analyses of heavy metals. The concentration of heavy metal (As, Cd, Cu, Cr, Fe, Pb, Mn, Ni, Se, and Zn) was determined using inductive coupled plasma mass spectrometry (ICP-MS). The distribution of heavy metals mean concentration in muscle is Zn > Fe > As > Se > Cr > Cu > Mn > Pb > Ni > Cd for L. calcarifer, Fe > Zn > Cr > As > Ni > Mn > Se > Cu > Pb > Cd for L. campechanus and Fe > Zn > Cr > Ni > Se > Cu > As > Mn > Pb > Cd for L. griseus. Among all of the species under investigation, the highest concentration of Fe was found in the muscle tissue of L. campechanus (19.985 ± 1.773 mg kg^-1) and liver tissue of L. griseus (58.248 ± 8.736 mg kg^-1). Meanwhile, L. calcarifer has the lowest concentration of Cd in both muscle (0.007 ± 0.004 mg kg^-1) and liver tissue (0.027 ± 0.016 mg kg^-1). The heavy metal concentration in muscle tissue is below the permissible limit guidelines stipulated by the Food & Agriculture Organization, 1983 and Malaysia Food Act, 1983. The concentration of heavy metals varies significantly among fish species and tissues. L. campechanus was found to have a higher ability to accumulate heavy metals as compared to the other two species (p < .00). Among all the studied fish, liver tissue has a higher concentration of heavy metals compared to muscle tissue (p < .05). The findings from this study can serve as baseline information for future monitoring and risk assessment studies. Periodic monitoring of heavy metal concentration in mariculture fish must be performed to prevent acute and chronic food intoxication.

Studies on seasonal pollution of heavy metals in water, sediment, fish and oyster from the Meiliang Bay of Taihu Lake in China

The present study, seasonal pollution of heavy metals (Pb, Cd, Cr and Cu) in water, sediment, tissues of fish Carassius carassius and oyster Crassostrea gigas were determined at seven sampling sites from Meiliang Bay, Taihu Lake during one year calendar, 2016. The total heavy metal concentrations in water samples were higher in winter and summer than in spring and autumn season, whereas in sediment they were higher in winter and summer seasons, respectively. The trend of metal mean contents found in the fish and oyster were in decreasing order of Pb > Cu > Cr > Cd and Pb > Cu > Cr > Cd, respectively. The tissues of fish and oyster captured during winter and summer accumulated a higher significant different amount of metals relative to other season, which was attributed to a higher influx of agricultural waste, sewage and sludge by heavy rainfall and floods. In addition, the pollution load index (PLI) values were above one (>1), indicating an advanced decline of the sediment quality, and contamination factor (CF) confirmed that the sediment samples were moderate to high contamination by Pb and Cr. Thus, comparative studies with seasonal pollution of heavy metals in Meiliang Bay of Lake Taihu regions indicate considerable heavy metal enrichment in water, sediments as well as in various organs of fish and oyster. Finally, our results indicated that the metal concentration values increased statistically significant different related to season (p < 0.001). The determination of heavy metal stress biomarkers in fish along with seasonal variations may serve as a convenient approach during pollution bio-monitoring programme.

Lead and Arsenic Accumulation and Its Effects on Plasma Cortisol Levels in Oreochromis sp

The accumulation, elimination and effect of heavy metals on plasma cortisol levels in Oreochromis sp. were studied in the exposure and recovery phases. In the exposure phase, the mean rate of accumulation in the tissues was in the order gill > liver > muscle for Pb exposure and muscle > liver > gill for As exposure. In the recovery phase, the order of elimination in the tissues was gill > liver > muscle for Pb and liver > gill > muscle for As. The amount of cortisol secreted by the Oreochromis sp. after Pb or As treatment was lower compared to Oreochromis sp. in the control group during the exposure phase. In the recovery phase, plasma cortisol levels in Oreochromis sp. increased in all Pb treatment groups while it continuously decreased in all As treatment groups. A fish affected by As has obvious difficulty recovering from the stress response. It was concluded that exposure to the tested concentrations of Pb and As over 20 days could be a potent endocrine disruptor, which may lead to adverse impacts on the health of the Oreochromis sp.

Trace metals in sediments and benthic animals from aquaculture ponds near a mangrove wetland in Southern China

In this study, we measured the concentrations of trace metals (Cr, Cu, Zn, As, Cd, Pb and Hg) in typical cultured animals (crabs, clams, and shrimps) and sediments from aquaculture ponds nearby mangrove wetlands in Zhangjiang estuary, China. The contents of Cr, Cu, Cd, and Pb in mangrove sediments were significantly higher than those in pond sediments, while an inverse distribution was observed for Zn, As, and Hg. Significantly higher concentrations of trace metals were found in clams from the mangrove mudflats compared to those from the aquaculture ponds. The sources of trace metals in the clams were primarily from organic fertilizer, whereas those in the shrimp were from contaminated sediment. The results of geo-accumulation index and the ecological risk assessment indicated that the aquaculture ponds near the mangrove wetlands in this subtropical estuary posed a special risk of endogenous and exogenous trace metal pollution to nearby systems.

The effects of mariculture on heavy metal distribution in sediments and cultured fish around the Pearl River Delta region, south China

Thirty-six sediment samples were collected from six mariculture sites and corresponding reference sites (approximately 200-300 m away from each mariculture site) to study the effects of mariculture on heavy metal: copper (Cu), zinc (Zn), chromium (Cr) and lead (Pb) distribution in sediments and cultured fish around the Pearl River Delta region, south China. The mean concentrations of Cu, Zn, Cr and Pb in all mariculture sediment samples were 109, 273, 99 and 33 mg/kg, compared with 63, 209, 56 and 23 mg/kg for reference sediment samples, respectively. The Pollution Load Index of sediment for each site was over 1, implying substantial heavy metal pollution. The results of principal component analysis and hierarchical clustering analysis indicate that marine aquaculture activities have enriched the surface sediments underneath mariculture rafts with Cu, Zn and Pb, possibly due to the accumulation of unconsumed fish feeds, fish excreta and antifouling paints (except Cr). Two kinds of fish feeds, feed pellets and trash fish commonly used in Hong Kong were analyzed. The concentrations of Zn and Cu contained in feed pellets were significantly higher (p < 0.05) than in trash fish due to addition of these elements as growth promoters during pellet production. However, the Pb content in trash fish (due to contamination) was significantly higher (p < 0.05) than in feed pellets. Three cultured fish species, namely red snapper (Lutjanus campechanus), orange-spotted grouper (Epinephelus coioides) and snubnose pompano (Trachinotus blochii), were collected from each mariculture site for metal analysis. Lead concentrations in 21 fish samples exceeded the Chinese safety guideline (0.5 mg/kg, GB18406.4-2001), indicating that Pb contamination in cultured fish would be a public health concern.

Assessment of health risk from heavy metal contamination of shellfish from the Persian Gulf

The present study assessed the risk of consumption of shrimp and lobster contaminated with mercury, arsenic, cadmium, and lead from the Persian Gulf. The concentrations of mercury, arsenic, lead, and cadmium in shrimp was 62.5, 178.2, 325.2, and 193.5 μg kg(-1) and in lobsters was 53.2, 103.9, 640.6, and 163.1 μg kg(-1), respectively. The maximum daily consumption of shrimp and lobster was calculated to estimate health risks associated with their consumption. The results showed that the maximum allowable consumption of shrimp and lobster was 18-140 g/day for mercury, 33-214 g/day for arsenic, 59-454 g/day for cadmium, and 72-916 g/day for lead. The concentration of metals was within recommended limits for human consumption with the exception of lead, which was found to be above acceptable levels and represents a health risk.

Transgenic expression of omega-3 PUFA synthesis genes improves zebrafish survival during Vibrio vulnificus infection

Background

Highly desaturated n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are synthesized by desaturases and elongase. They exert hepatoprotective effects to prevent alcoholic fatty liver syndrome or cholestatic liver injury. However, it is unclear how n-3 PUFAs improve immune function in liver. Vibrio vulnificus, a gram-negative bacterial pathogen, causes high mortality of aquaculture fishes upon infection. Humans can become infected with V. vulnificus through open wounds or by eating raw seafood, and such infections may result in systemic septicemia. Moreover, patients with liver diseases are vulnerable to infection, and are more likely than healthy persons to present with liver inflammation following infection. This study quantified n-3 PUFAs and their anti-bacterial effects in Fadsd6 and Elvol5a transgenic zebrafish.

Results

Two transgenic zebrafish strains with strong liver specific expression of Fadsd6 and Elvol5a (driven by the zebrafish Fabp10 promoter) were established using the Tol2 system. Synthesis of n-3 PUFAs in these strains were increased by 2.5-fold as compared to wild type (Wt) fish. The survival rate in 24 h following challenge with V. vulnificus was 20 % in Wt, but 70 % in the transgenic strains. In addition, the bacteria counts in transgenic fish strains were significantly decreased. The expression levels of pro-inflammatory genes, such as TNF-α, IL-1β, and NF-κB, were suppressed between 9 and 12 h after challenge. This study confirms the anti-bacterial function of n-3 PUFAs in a transgenic zebrafish model.

Conclusions

Fadsd6 and Elvol5a transgenic zebrafish are more resistant to V. vulnificus infection, and enhance survival by diminishing the attendant inflammatory response.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-015-0208-1) contains supplementary material, which is available to authorized users.

In vivo induction of antioxidant response and oxidative stress associated with genotoxicity and histopathological alteration in two commercial fish species due to heavy metals exposure in northern India (Kali) river

Heavy metals can significantly bioaccumulate in fish tissues. The step wise mechanism of heavy metal toxicities on fish health is still limited. The present study assessed the tissue-specific antioxidant response and oxidative stress biomarkers of commercially important fish species namely, Channa striatus and Heteropneustes fossilis inhabiting Kali River of northern India where heavy-metal load is beyond the World Health Organisation - maximum permissible limits. Heavy metals chromium (Cr), nickel (Ni), lead (Pb) and cadmium (Cd) were elevated in both fish species compared to recommended values of the Federal Environmental Protection Agency (FEPA), 1999 for edible fishes. Reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CATA) activities in all tissues (brachial, neural, renal and hepatic) were altered. Cellular lipid and protein compromisation in both fishes induced by heavy metals was determined by lipid peroxidation (LPO) and protein carbonylation (PC) assays. Micronucleus (MN) test of erythrocytes and comet assay of liver cells confirmed genotoxicity. Histopathology of the liver, kidney and brain of affected fishes was distorted significantly with its reference fishes thereby affecting the quality and quantity of these fish stocks. This raises a serious concern as these fishes are consumed by the local population which would ultimately affect human health.

Dietary metal toxicity to the marine sea hare, Aplysia californica

Metal pollution from anthropogenic inputs is a concern in many marine environments. Metals accumulate in tissue and in excess cause toxicity in marine organisms. This study investigated the accumulation and effects of dietary metals in a macroinvertebrate. The green seaweed, Ulva lactuca and the red seaweed, Agardhiella subulata were each concurrently exposed to two concentrations (100 or 1000 μg/L) of five metals (Cu, Ni, Pb, Cd, and Zn). Additionally, U. lactuca was exposed to 10 μg/L of the metal mixture as well as 10 or 100 μg/L of each metal individually for 48 h. The seaweeds were then used as food for the sea hare, Aplysia californica for two to three weeks depending on the exposure concentration. Body mass of A. californica was measured weekly, and at the end of the exposure duration, metal concentrations were quantified in dissected organs (mouth, esophagus, crop, gizzard, ovotestis, heart, hepatopancreas, gill, and the carcass). Metal distribution and accumulation in the organs of A. californica varied with the metal. A. californica fed the metal-exposed diets had significantly reduced body weight by the end of the exposure periods, as compared to controls; however, differences were observed in the extent of growth reductions, dependent on exposure concentration, duration, and exposure regime (metal mixture versus individual metal-exposed diet). Metal mixture diets decreased A. californica growth more so than comparable individual metal diets, despite more metal accumulating in the individual metal diets. Additionally, Zn- and Cu-contaminated algal diets decreased control-normalized growth of A. californica significantly more than comparable Cd-, Pb-, or Ni-contaminated diets. The seaweed diets in this study contained environmentally relevant tissue metal burdens. Therefore, these results have implications for metals in marine systems.

Chromium [Cr(VI)] biosorption property of the newly isolated actinobacterial probiont Streptomyces werraensis LD22

The present work demonstrates the heavy metal resistance and detoxification of Cr(VI) by the probiotic actinobacterial cultures isolated from chicken and goat feces. The actinobacterial isolates were screened for heavy metal resistance by qualitative, semiquantitative assays and Cr(VI) biosorption was determined by analytical techniques such as atomic absorption spectrophotometry and Fourier transform infrared spectrometry (FT-IR). All the tested actinobacterial isolates (n = 20) showed resistance toward K₂Cr₂O₇, NiCl₂, ZnCl₂, CuSO₄ and PbNO₃ at 20 mg L⁻¹ concentration. The maximum tolerance concentration values were found to be 200–250 mg L⁻¹ for K₂Cr₂O₇, 100–250 mg L⁻¹ for PbNO₃ and <50–250 mg L⁻¹ for NiCl₂, ZnCl₂ and CuSO₄. Among the five tested heavy metals, Cr(VI) was resisted by 95 % of the tested actinobacterial cultures up to 250 mg L⁻¹ concentration; particularly, the isolate LD22 exhibited a high degree of tolerance to all the tested heavy metals. Thus, the isolate was justifiably chosen for Cr(VI) biosorption study and the biosorption efficacy was found maximum at 100 mg L⁻¹ of metal ion concentration (3 g L⁻¹ of biomass dosage and pH 7.0). FT-IR spectrum revealed the chemical interactions between the hydroxyl, amine and carboxyl groups of the biomass and the metal ions. On the basis of phenotypic, physiological, biochemical and molecular characteristics the isolate LD22 was identified as Streptomyces werraensis LD22 (JX524481) which could be used to develop a biosorbent for adsorbing Cr(VI) metal ions.

Absorption of metals in mulloway (Argyrosomus japonicus) after ingesting nickel-plated carbon-steel hooks

Previous research has alluded to the potential of metals being absorbed by fish after ingesting fishing hooks, which may have adverse effects on fish health and the organisms that consume them. Subsequently, this study aimed to quantify the potential of mulloway (Argyrosomus japonicus) to absorb metals during the decay of ingested nickel-plated carbon-steel hooks. Twenty-five treatment fish were allowed to ingest nickel-plated carbon-steel hooks during angling and then monitored with 25 controls (untreated fish) for up to 42 days for hook ejection and mortality. Blood, liver and muscle samples were collected from treatment, control and 14 wild-caught individuals to determine the concentrations of chromium, cobalt, copper, iron, manganese and nickel. The results showed that increased oxidation influenced hook ejection, and that hook-ingested fish had significantly elevated concentrations of nickel in their liver and blood, but not muscle. This research has shown that there is an avenue for metal absorption from ingested hooks.

Histopathology and bioaccumulation of heavy metals (Cr, Ni and Pb) in fish (Channa striatus and Heteropneustes fossilis) tissue: a study for toxicity and ecological impacts

Abstract: The water samples were collected from the 22 km segment III of Yamuna River from Okhla barrage. This segment receives water from 17 sewage drains of Delhi, Western Yamuna Canal (WYC), upper Ganga canal via Najafgarh drain and Hindon cut canal. Hence, the water samples collected were used to determine the presence of Chromium, Nickel and Lead through Atomic Absorption Spectrophotometry. The concentration of these heavy metals were much above the maximum permissible limits set by WHO. This was bound to have its influence on the riverine flora and fauna. To evaluate this, two popularly consumed fish species such as Channa striatus and Heteropneustes fossilis were caught and the bioaccumulation of these heavy metals were estimated in different organs (liver, kidney, gill and muscle). It was found that Cr accumulated the most in these organs (gill being most influenced) in both the species. The accumulation of all these heavy metals were above MPL set by World Health Organisation (WHO) and Food and Drug Administration (FDA). Histopathology was also conducted where heavy damages were observed in both liver and kidney of both the species.

The trace element analysis in freshwater fish species, water and sediment in Iyidere stream (Rize-Turkey)

Many environmental problems like dam construction, agricultural debris, flooding and industrial establishments threaten Iyidere stream (Rize, Turkey) on the southeastern coast of the Black Sea (Turkey). The trace element concentrations in water, fish and sediments in lyidere stream (Rize, Turkey) were investigated in this study. The concentration of six different elements in ten freshwater fish species and sediment was determined using energy dispersive X-ray fluorescence method. A radioisotope excited X-ray fluorescence analysis using the method of multiple standard addition is applied for the elemental analysis of fish and sediments. Water samples for trace metals were analyzed using standard spectrophotometry methods. A qualitative analysis of spectral peaks showed that ten different freshwater fish samples (Chondrostoma colchicum, Chalcalburnus chalcoides, Salmo trutta labrax, Alburnoides bipunctatus, Leuciscus cephalus, Barbus taurus escherichia, Capoeta tinca, Neogobius kessleri, Rutilus frisii, Lampetra lanceolata) and sediment contained phosphorus (P), sulphur (S), chlorine (Cl), potassium (K), calcium (Ca) and titanium (Ti). Heavy metals as toxic elements for biota (Pb, Cd, Hg, Zn and Mn etc.) were not detected in fish, water and sediments. Thus, It can be declared that freshwater fish of Iyidere does not contains health risks for consumers in terms of metal pollution.

Inhibition of larval swimming activity of the coral (Platygyra acuta) by interactive thermal and chemical stresses

This study examined the interactive effects of copper and elevated temperature and subsequent depuration on Platygyra acuta coral larvae. Larval mortality and motility were significantly affected by copper alone (70% and 100% inhibition respectively). Their respective lethal/inhibitory concentration (LC50/IC50) were 10-130% and 86-193% higher than those reported for other larvae. Temperature (ambient, 27°C and elevated, 30°C) alone and the combination of temperature and copper did not significantly affect both endpoints. This study provides the first quantitative data on depuration effect on resumption of larval motility after copper exposure, although no sign of larval recovery was observed. These findings suggest that the effects of copper pollution outweigh the thermal tolerance of coral larvae. High LC50 and IC50 recorded may be unique for corals from marginal reefs like Hong Kong which have already been exposed to high levels of copper pollution.

Health risk assessment for consumption of fish originating from ponds near Dabaoshan mine, South China

Mining effluents are a potential source of toxic metals in the surrounding aquatic ecosystem and pose a potential health risk to humans from fish consumption. The objective of this paper is to assess the impact of the long-term Dabaoshan mining operation on heavy metal accumulation in different fish species. Heavy metal accumulation (lead (Pb), cadmium (Cd), zinc (Zn), and copper (Cu)) in four tissues (liver, muscle, intestine, and gills) of five carp species (Hypophthalmichthys molitrix, Ctenopharyngodon idellus, Megalobrama amblycephala, Aristichthys nobilis, and Carassius auratus auratus) from two fishponds exposed to effluent waters from Dabaoshan mine, South China. The bioaccumulation factor (BAF) and target hazard quotients were calculated to assess potential health risks to local residents through fish consumption. Levels of heavy metals varied depending on the analyzed tissues. C. auratus auratus accumulated the higher Pb, Cd, Zn, and Cu in the intestine compared with other fish species. Liver of all five species contained high concentrations of Pb, Cd, Zn, and Cu. The BAF for the studied metals showed a descending order of Cd>Zn>Cu>Pb for fishpond 1 and Zn>Cd>Cu>Pb for fishpond 2. Risk assessments suggested that potential human health risk may be present due to high Pb and Cd concentration in the muscle of some fish species exceeding the national and international limits, although the target hazard quotients were less than one.

Evaluation of metal pollution in fish and water collected from Gorgan coast of the Caspian Sea, Iran

In this study, concentrations of zinc, chromium, cadmium and lead were determined in water and three species of fish sampled from 10 selected stations along Gorgan coast using atomic absorption spectrophotometery, summer 2009. Mean lead levels in water and fish samples (119.50 ± 22.24 μg/L and 113.80 ± 33.11 μg/kg) were significantly higher than that of cadmium and chromium (p < 0.05). Cyprinus carpio had highest metals content than Mugila auratus and Rutilus frisikutum. The evaluated metals values in water collected from Gomishan wetland (Pb, Cd, Cr and Zn values are 145.31 ± 35.32, 120.46 ± 11.44, 96.47 ± 6.05 and 82.02 ± 34.37 μg/L, respectively) were higher than the other sampling sites. The result is consistent with the findings accessed by evaluation of the metals in fish specimens. The metals concentrations in the fish and water samples were below the recommended limits. But, elevating levels of metals in water and fish made a serious concern about ecosystem and food chain contamination.

Characterization of lactic acid bacteria-based probiotics as potential heavy metal sorbents

AIM

To isolate and characterize lactic acid bacteria (LAB) and determine whether they could potentially be used as heavy metal (cadmium and lead) absorbing probiotics.

METHODS AND RESULTS

The study used 53 environmental (mud and sludge) samples to isolate cadmium- and lead-resistant LAB, by following spared plate technique. A total of 255 cadmium- and lead-resistant LAB were isolated from these samples. The survival of 26 of the LAB was found after passing through sequential probiotic characterizations. These 26 probiotic LAB exhibited remarkable variations in their metal-resistant and metal-removal abilities. Of 26, seven (Cd54-2, Cd61-7, Cd69-12, Cd70-13, Pb82-8, Pb96-19 and Cd109-16) and four (Pb71-1, Pb73-2, Pb85-9 and Pb96-19) strains displayed relatively elevated cadmium- and lead-removal efficiencies from water, respectively, compare with that of the remaining strains. Strains Cd70-13 and Pb71-1 showed the highest cadmium (25%) and lead (59%) removal capacity from MRS (De Man, Rogosa and Sharpe) culture medium, respectively, amongst the selected strains and showed a good adhesive ability on fish mucus. A phylogenetic analysis of their 16S rDNA sequences revealed that the strains Cd70-13 and Pb71-1 belong to Lactobacillus reuteri.

CONCLUSION

Excellent probiotic, metal sorption and adhesive characteristics of newly identified Lact. reuteri strains Cd70-13 and Pb71-1 were isolated, which indicated their high potential abilities to survive in the intestinal milieu and to uptake the tested metals from the environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first study that has aimed to isolate, characterize and identify metal-resistant LAB strains that have potential to be a probiotic candidate for food and in vivo challenge studies in the intestinal milieu of fish for the uptake and control of heavy metal bioaccumulation.

Heavy metal pollution in sediments of a typical mariculture zone in South China

The heavy metal inventory and the ecological risk of the estuarine sediments in Hailing Bay, an important maricultural zone along the southern coast of China, were investigated. Results show that the surface sediments were mainly polluted by As (2.17-20.34 mg/kg), Ni (1.37-42.50mg/kg), Cu (1.21-58.84 mg/kg) and Zn (11.69-219.22 mg/kg). Furthermore, the aquafarming zone was significantly more polluted than the non-aquafarming zone, and cluster analysis suggested additional sources of heavy metal input in the aquafarming zone. As, Cr, Cu, Ni, Pb and Zn were mainly present in the non-bioavailable residual form in the surface sediments, whereas Cd was predominantly in the highly mobile acid soluble and reducible fractions. The ecological risk of the polluted sediments stemmed mainly from Cd, and from As, Cu and Pb to less degrees. The highest potential risks occurred near the aquaculture base, indicating the need to control heavy metal inputs from aquafarming activities.

Metal concentrations in two bioindicator fish species, Merlangius merlangus, Mullus Barbatus, captured from the West Black Sea coasts (Bartin) of Turkey

The Black Sea is very vulnerable to originating from land based human activities and its health is equally dependent on the coastal and non-coastal states of its basin. Total concentrations of cadmium, copper, zinc, lead, nickel, aluminum, iron, manganese, boron and chromium concentrations were determined in Merlangius merlangus (whiting) and Mullus barbatus found in Amasra in the West Coast of the Black Sea (Turkey). The metal contents that were measured in head and muscle was expressed in μg g(-1) wet weight. On average, while the highest Fe (344.25 μg g(-1)), Mn (10.35 μg g(-1)), Cr (0.96 μg g(-1)) and Al (76.77 μg g(-1)) concentrations were measured in the heads of M. merlangus and the highest Zn (77.99 μg g(-1)), Cu(8.53 μg g(-1)), B (44.83 μg g(-1)), Ni (1.96 μg g(-1)), Cd (0.40 μg g(-1)) and Pb (6.80 μg g(-1)) concentrations were detected in the muscles of M. merlangus. There were significant differences between metal levels of muscles in these two species. In terms of permissible levels reported by WHO FAO and TSE, there is not any risk for human consumption for both M. merlangus and M. barbatus, for Pb.

Heavy metals (Zn, Pb, Cd and Cr) in fish, water and sediments sampled form Southern Caspian Sea, Iran

Environmental pollution is a worldwide problem, heavy metals belonging to the most important pollutants. The progress of industries has led to increased emission of pollutants into ecosystems. Southern Caspian Sea coast is one of the most important aquasystems at the eastern south of Caspian Sea, which receives effluents discharges from heavily industrialized and highly populated settlements. Metals tend to accumulate in water and move up through the food chain. So, studies to ascertain the level of heavy metals in environment and determine potentially hazardous levels for human are necessary. In this investigation, concentration of four heavy metals (zinc [Zn], chromium (Cr), cadmium, [Cd] and lead [Pb]) in three species of most-consumed fishes, water and sediments have been determined. Samples were collected from 10 stations along the Southern coast of Caspian Sea, in spring 2008. Heavy metal concentrations were measured by graphite furnace atomic absorption spectrometry. Then, the data were analyzed by means of one-way analysis of variance (ANOVA) statistical analysis. The results showed that the highest concentration of heavy metals in water and fish and sediment samples were related to Pb and Zn. The minimal and maximal concentrations of these metals in fishes, water and sediments were 53.67-2360.67 and 50.36-2497.25 for Pb and Zn, respectively. However, the observed heavy metals concentrations in fish, water and sediments were below the recommended limits. The investigation showed elevating levels of heavy metals in environment. Thus, a serious notification to industrial and manmade pollution, which can lead to ecosystem and food chain contamination, is necessary.

Trace elements in two marine fish cultured in fish cages in Fujian province, China

Two cultured marine fish, the Japanese seabass (Lateolabrax japonicus) and red seabream (Pagrus major) were collected from eight fish cage sites along the coast of Fujian province in China. The concentrations of Ag, As, Cd, Co, Cu, Fe, Mn, Se, and Zn in their muscle, stomach and liver tissue were quantified. The risk of these trace elements to humans through fish consumption was then assessed. The highest concentrations of As, Cd, Se and Zn in fish feed from fish cages were found in Dongshan Station. Moreover, the As levels in the muscles of both species at all sites were generally higher than China's national standard (>1.0 microg/g). Trace element concentrations in two marine fish followed the order of livers > stomachs > muscles. Although the As levels in two marine caged fish exceeded the permissible standards, the estimated daily intake of As did not exceed the reference dose guideline established by US EPA. For other trace elements examined in this study, their concentrations did not exceed the permissible concentrations of the international standards.

Copper affects biofilm inductiveness to larval settlement of the serpulid polychaete Hydroides elegans (Haswell)

Copper (Cu) contamination is a potential threat to the marine environment due to the use of Cu-based antifouling paints. Cu stress on larval settlement of the polychaete Hydroides elegans was investigated, and this was linked to Cu stress on biofilms and on the biofilm development process. The inductiveness of young biofilms was more easily altered by Cu stress than that of old biofilms, indicating the relative vulnerability of young biofilms. This might result from changes in bacterial survival, the bacterial community composition and the chemical profiles of young biofilms. Cu also affected biofilm development and the chemical high performance liquid chromatograph fingerprint profile. The results indicate that Cu affected larval settlement mainly through its effect on the process of biofilm development in the marine environment, and the chemical profile was crucial to biofilm inductiveness. It is strongly recommended that the effects of environmentally toxic substances on biofilms are evaluated in ecotoxicity bioassays using larval settlement of invertebrates as the end point.

Bioaccumulation of heavy metals in fish tissues of a freshwater lake of Bhopal

Contamination of heavy metals, namely, lead, cadmium, zinc, nickel, copper, chromium and mercury was evaluated in the samples of water and tissues of Labeo rohita and Ctenopharyngodon idella of Upper Lake of Bhopal collected during summer, rainy and winter seasons of 2005-2006. Different organs of the fishes accumulated varying quantities of different heavy metals. In L. rohita, accumulation of heavy metals was in the sequence liver>kidney>gills>muscles, and in C. idella, it was gills>liver>kidney>muscles. Zn was the highest accumulating metal in fish, whilst Hg was the lowest and was well corroborated with those of water. The values of heavy metals were so far well within the maximum permissible standard value of heavy metals for drinking water and for fish culture as prescribed by various national and international agencies.

Function of metallothioneins in carp Cyprinus carpio from two field sites in Western Ukraine

The aim of the present study was to elucidate the seasonal and spatial regularity of the properties of metallothioneins (MT) from the liver and gills of carp Cyprinus carpio L. in rural (R) and industrial (I) sites in Western Ukraine. The MT is represented by two chromatographic forms, the features of which exhibit seasonal rather than spatial dependence. The pronounced differences between the sites were due to the lower levels of Zn in the liver and the higher levels of Zn in MT of carp from site I, providing evidence of the higher overall anthropogenic impact here that leads to the distortion of this essential metal accumulation and to the activation of metal-binding function of MT. In spring, higher levels of Cu and Cd in MT and in the tissues were reflected at site R probably as the result of the permitting pollution here. The principal component analysis demonstrated the correlation of MT-bound metal levels to their levels in water and the absence of such relation for general tissue metal levels for Zn.

Total mercury distribution in different tissues of frigate tuna (Auxis thazard thazard) from the Atlantic Coastal Waters of Ghana, Gulf of Guinea

Total mercury concentrations in different tissues of frigate tuna fish (Auxis thazard thazard) was determined by the cold vapour atomic absorption spectrometry technique using an automatic mercury analyzer. A mixture of HNO3, HClO4 and H(2)SO(4) was used for complete oxidation of organic tissue. The concentration of mercury obtained was in the order Gills < Stomach < Gonads < Intestine < Heart < Duodenum < Liver < Muscle. The concentration of total mercury detected in the edible muscle tissue of the tuna fish tested ranged from 0.044 to 0.201 microg g(-1) (mean = 0.108 microg g(-1)) wet weight. These levels are all within the maximum allowed/recommended level in fish (0.5 mug g(-1) wet weight) set by the Food and Agriculture Organisation/World Health Organisation (FAO/WHO) and are therefore unlikely to constitute any significant mercury exposure to the general population because of consumption of tuna fish. The results of the study suggest a relatively clean marine environment that has not been significantly impacted by mercury contamination probably due to minimal industrial activity in the region.

Bioaccumulation of heavy metals in fishes from Taihu Lake, China

The Cr, Zn, Cu, Cd, Pb contents were determined in Cyprinus carpio Linnaeus, Carassius auratus Linnaeus, Hypophthalmichthys molitrix and Aristichthys nobilis, which were caught from Meiliang Bay, Taihu Lake, a large, shallow and eutrophic lake of China. The results showed that: (1) the Cr, Cu, Pb, Cd contents in the edible parts of the four fish species were much lower than Chinese Food Health Criterion (1994), but the Zn contents were higher than the Criterion; (2) Cd contents were the highest in the liver of fish, Pb contents were almost the same in all organs of fish, Cr contents mainly enriched in the skin and gonads, Zn contents were the highest in the gonad (female), and Cu contents were the highest in the liver; (3) the total metal accumulation was the greatest in the liver and the lowest in the muscle. The total metal accumulation was the highest in C. auratus L. This investigation indicated that fish products in Taihu Lake were still safe for human consumption, but the amount consumed should be controlled under the Chinese Food Health Criterion to avoid excessive intake of Zn.

Toxic effects of copper on larval development of the barnacle Balanus amphitrite

Experiments were conducted to assess the effects of copper on larval development in the barnacle Balanus amphitrite. In the first experiment, we compared the sensitivity of three naupliar stages to copper stress. Molting inhibition occurred at copper concentrations ranging from 32 microg l(-1) in nauplius II to 128 g l(-1) in nauplius VI. EC50 for molting ranged from 97 microg l(-1) in nauplius II to 129 g l(-1) in nauplius VI. Decreased survival occurred at 128 microg Cu l(-1) in all of the naupliar stages tested, with LC50 ranging from 145 in nauplius II to 213 microg l(-1) in nauplius VI. In the second experiment, we examined effects of copper on the development from nauplius II to cyprid. The larvae reached cypris stage only in treatments of 16 microg Cu l(-1). Our study therefore showed that molting was a more sensitive endpoint than survival, nauplius II was the most sensitive naupliar stage, and that whole larval development assay was more sensitive than assays using a particular larval stage. The results were discussed with respect to the use of this species in toxicity tests.