Bioaccumulation Of Metals In Fish Research Articles

Differential accumulation of metals in the lacustrine and fluvial Alpine bullheads (Cottus poecilopus) and recovery of fish from metal contamination after a flash flood

The spatiotemporal distribution and transport of mercury, zinc, molybdenum, rubidium, and strontium from alpine terrestrial ecosystems to alpine lake and mountain stream populations of Cottus poecilopus were investigated. Metals were measured for 66 wild fish collected from different lakes and Javorinka stream across. Mercury was measured in the pectoral fins, other elements in the skull. Bullheads contained more metals in the alpine lakes than in the mountain stream. In particular, mercury and zinc concentrations in lake bullheads were 6 and 2.5 times higher, respectively, than those of stream-dwelling fish. New data were generated on metal bioaccumulation in fish of understudied West Carpathian alpine lake environments. In July 2018, a major flood occurred in the area of the Javorinka. Already then, the mercury content in bullheads increased significantly. Bioaccumulation of mercury in fish occurred very quickly after the flood and was also significant in the following 2019. Then, the concentrations of mercury quickly decreased up to 70% in 2021–2022. Average concentrations of molybdenum and rubidium in bullheads in the stream rapidly declined in the year following the flood disturbance, but within less than 2 years, the metal levels stabilized at about the same level as in 2017 prior the flood. Strontium concentrations in fish dropped rapidly immediately after the flood, increased in the following years, and dropped again after 4 years, suggesting that many more factors are influencing strontium bioaccumulation in fish that are comparable in magnitude to the flood. The most serious warning seems to be the absence of biogenic zinc. The average concentration in the Alpine bullheads population in the stream has declined by 70% in less than 5 years and is steadily declining. An important result of this study is the demonstration that disturbance by a single factor (heavy rainfall and flooding) has a clear and timely effect on average metal concentrations in the fish population.Graphical abstract

Feeding Habit-Specific Heavy Metal Bioaccumulation and Health Risk Assessment of Fish in a Tropical Reservoir in Southern China

Dietary uptake is well known as the predominant pathway of heavy metal bioaccumulation in organisms. Our study used a typical tropical reservoir and fish as a modeling system to test the hypothesis that feeding habits and living habitats significantly affect heavy metal bioaccumulation in fish. Specifically, Cr, Mn, Fe, Ni, Cu, Zn, Cd, and Pb concentrations in water, sediment, and fish, and δ13C and δ15N in 13 fish species were detected in the Songtao Reservoir of Hainan Province, southern China. Our results indicated that Zn concentration in carnivorous fish was higher than in omnivorous fish. Principal components analysis visually differentiated pelagic, benthopelagic, and demersal fish groups. Moreover, we found that the fish feeding in the demersal habitat showed higher heavy metal levels than those in the pelagic habitat. Additionally, the heavy metal contents in demersal fish were significantly positively correlated with sediments, while no positive correlation was observed in pelagic-feeding fish. The δ15N and the concentration of Ni, Zn in fish had a significantly positive correlation, suggesting the potential biomagnification. In contrast, Ni, Fe, Cu, and Cd negatively correlated with fish body weight/length, indicating the growth dilution effects. Finally, the estimated daily intake (EDI) of the metals was far below the provisional tolerable daily intake (PTDI), and target hazard quotients (THQ) were <1.0, indicating that the fish had no risk for consumption risks. Overall, our finding partially validated the hypothesis that the feeding habits and living habitats significantly influence heavy metal bioaccumulation in fish, which might be a broad generality for metal exposure scenarios in aquatic environments.

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.

Analysis of Trace Metal Bioaccumulation in Fish and Man; Health Risk Impact

Trace metals occur during natural processes and are also obtained during anthropogenic activities. Streams, lakes and rivers surrounded by farmlands engaged in the use of Trace metal-enriched fertilizers have shown a possible and positive correlation to the rise of Trace metals in the use of chemical, organic and water-soluble fertilizers for a long period. there is a tendency for high correlations of trace metals in source waters. Furthermore, the increasing level of trace metals in fish is alarming and has spurred scientists to make research on the dangers caused by the trace metals resulting in trace metal accumulation and bioaccumulation of life cells. This study aims at assessing the possible sources of trace metals in the aquatic environment, the impact of Trace metals in the aquatic environment, their bioaccumulation in fish and human health risk impact, negative effects in fish have been attributed to the accumulation of trace metals such as irritation of the gastrointestinal mucosa, nephritis, necrosis, neurological and behavioural disorders and death amongst others). The ingestion, absorption and uptake of trace metals in fish are usually toxic and result in harmful damage to the fish and fish life. Since most of the metals taken up are non-biodegradable, such metals can bioaccumulate and bio-magnify. Over time, the accumulated metals affect the growth and development stages of fish from the production of viable eggs, hatchability laval, fingerlings and juvenile life stages. This is so because the early life stages are more sensitive than during maturing and adulthood. In conclusion, negative results of the presence of trace metals and the effect of bioaccumulation and bio-magnification have been reviewed in this paper. This study recommends that the proper assessment and treatment of all forms of wastewater, agricultural waste, sewage, and industrial effluents be carried out before their discharge into the environment.

Bioaccumulation of metals in fish of different diets from hydro-accumulations on the Neretva River, Bosnia and Herzegovina

There is a growing need to assess the level of contaminants in fish as bioindicators of the health and well-being of fish and humans as its consumers. Contamination by heavy metals (Cd, Cr, Cu, Fe, Mn, Pb, Zn) was evaluated using atomic absorption spectrometer, flame and graphite furnace technique in the water samples and fish muscle tissues of Sander lucioperca, Leuciscus svallize and Tinca tinca of four hydro-accumulation lakes on the Neretva River, Bosnia and Herzegovina. Samples were collected during two seasons: autumn-winter and spring-summer (2019). It has been shown that iron (Fe) was the highest accumulating metal in fish, whilst cadmium (Cd) and lead (Pb) were the lowest. Heavy metals contents were below the maximum permissible for drinking water and for fish as prescribed by national legislation. According to correlation matrix between metals content in all fish during both fishing seasons, the highest values of the Pearson coefficient were obtained in the case of essential elements (Fe, Mn, Cu and Zn) and Fe and Mn also had a statistically significant correlation with Cd and Pb. Furthermore, potential health risk assessment exposure of the adult population in B&amp;H revealed that none of the seven heavy metals pose risk to human health, based on the estimated daily intake via consumption of these fish species as well as target hazard quotient and hazard index values less than 1.

Bioaccumulation of metals in fish of different diets from hydroaccumulations on the Neretva River, Bosnia and Herzegovina

There is a growing need to assess the level of contaminants in fish as bioindicators of the health and well-being of fish and humans as its consumers. Contamination by heavy metals (Cd, Cr, Cu, Fe, Mn, Pb, Zn) was evaluated using atomic absorption spectrometer, flame and graphite furnace technique in the water samples and fish muscle tissues of Sander lucioperca, Leuciscus svallize and Tinca tinca of four hydro-accumulation lakes on the Neretva River, Bosnia and Herzegovina.Samples were collected during two seasons: autumn-winter and spring-summer (2019). It has been shown that iron (Fe) was the highest accumulating metal in fish, whilst cadmium (Cd) and lead (Pb) were the lowest. Heavy metals contents were below the maximum permissible for drinking water and for fish as prescribed by national legislation. According to correlation matrix between metals content in all fish during both fishing seasons, the highest values of the Pearson coefficient were obtained in the case of essential elements (Fe, Mn, Cu and Zn) and Fe and Mn also had a statistically significant correlation with Cd and Pb. Furthermore, potential health risk assessment exposure of the adult population in B&amp;H revealed that none of the seven heavy metals pose risk to human health, based on the estimated daily intake via consumption of these fish species as well as target hazard quotient and hazard index values less than 1.

Metal bioaccumulation in fish from the Araguari River (Amazon biome) and human health risks from fish consumption.

Recently, high concentrations of metals have been found in the waters from sampling sites located in the Araguari River lower section. These metals can be bioaccumulated by fish, but also biomagnified, representing a potential risk through human consumption. Here, we aimed to (1) determine the metal concentrations in muscle samples from fish; (2) evaluate bioaccumulation of metals in muscle tissue of fish species with different feeding behaviors; and (3) investigate the risks of single metals, as well as mixture of metals, to human fish consumption. Eleven fish species were sampled (3 carnivorous, 5 omnivorous, and 3 detritivorous). In four fish species, Cd and Pb concentrations exceeded the Brazilian maximum limits (MLs) for human consumption. Individually, Pb and Cd concentrations in the muscle of these fish indicate risks to human health. When considering the mixture of metals, the consumption of all fish species represents risks. The highest risks implicate detritivorous species. For all fish species evaluated, the estimated daily intake (EDI) of Hg shows values above its reference dose (RfD). Our results suggest the need to establish an environmental monitoring program that aims to preserve environmental quality, biodiversity, and human health. It is also necessary to develop actions that aim to educate Amazonian populations on safe fish preparation and consumption.

Bioaccumulation of heavy metals in fish and shellfish from Rupsa River, Bangladesh, and risk assessment for human

Spatial variation of Pb, Hg, Cr, Cd and As concentrations between up- and downstream fish (river shad Tenualosa ilisha, silver jewfish Otolithoides pama) and shellfish (black tiger shrimp Penaeus monodon) collected from Rupsa River of the south-west coast of Bangladesh was studied in order to assess the potential health risks in human. Samples (n=18) were collected representing 3 species from two locations of the river system and muscle analyzed for heavy metal concentration. Mean concentration of the elements was significantly higher (p&lt;0.05) in the downstream samples compared to those of the upstream with a high concentration in benthic fauna and interspecific variation at a trend: black tiger shrimp &gt; Hilsa shad &gt; silver jewfish and distribution As&gt;Cr&gt;Hg&gt;Cd&gt;Pb. Bioaccumulation of As and Hg was correlated well with fish size although their concentrations were well below the international legislation limits set by WHO and FAO. For potential human health risk, the estimated daily intake (EDI), target hazard quotient (THQ) and total target hazard quotient (TTHQ) for non-carcinogenic risk suggest that most of the values were within the acceptable limits for all species expect As. Besides, the carcinogenic risk (CR) values indicate less prone to cancer risk yet CR values of Cd and As in both black tiger shrimp and Hilsa shad were close to the unacceptable range.&#x0D;

Utility of Fishes as Bio-indicators for Tracing Metal Pollution in the Cochin Backwaters, Kerala, India

Trace metal (Fe, Ni, Zn, Cu, Pb, Cd and Cr) concentrations in water and tissues (flesh, gills and liver) of two fishes, Etroplus suratensis Arius arius and from the Cochin backwaters were investigated during February 2017 to January 2018. Trace metals were analysed using an Atomic Absorption Spectrophotometer (AAS). The omnivorous species, showed a higher concentration of trace metals E. suratensis in tissues than the carnivorous species, . Bioaccumulation of metals in fish tissues showed higher levels in the liver, which was followed A. arius by gill and flesh . Bioaccumulation factors (B F) of metals maybe due to the different physiological roles of these organs in fish metabolism Acalculated for the species, follows an order Fe &gt; Zn &gt; Ni &gt; Cu &gt; Cr &gt; Pb &gt; Cd whereas that for the species, follows an E. suratensis A. ariusanother order Fe &gt; Zn &gt; Cr &gt; Cu &gt; Ni &gt; Pb &gt; Cd. Comparatively higher BAF values in organs of fishes indicate the increased concentration of the soluble metal in the medium in which the fishes inhabit. Metal selectivity index (MSI) and tissue selectivity index (TSI) are better tool for explaining bioaccumulation of trace metals in fishes. The results of the present study suggest the potential use of fishes, and E. suratensis A. arius as bioindicators for tracing metal pollution in the estuarine environment of Cochin.

Contamination and oxidative stress biomarkers in estuarine fish following a mine tailing disaster.

BackgroundThe Rio Doce estuary, in Brazil, was impacted by the deposition of iron mine tailings, caused by the collapse of a dam in 2015. Based on published baseline datasets, the estuary has been experiencing chronic trace metal contamination effects since 2017, with potential bioaccumulation in fishes and human health risks. As metal and metalloid concentrations in aquatic ecosystems pose severe threats to the aquatic biota, we hypothesized that the trace metals in estuarine sediments nearly two years after the disaster would lead to bioaccumulation in demersal fishes and result in the biosynthesis of metal-responsive proteins.MethodsWe measured As, Cd, Cr, Cu, Fe, Mn, Pb, Se and Zn concentrations in sediment samples in August 2017 and compared to published baseline levels. Also, trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Se and Zn) and protein (metallothionein and reduced glutathione) concentrations were quantified in the liver and muscle tissues of five fish species (Cathorops spixii, Genidens genidens, Eugerres brasilianus, Diapterus rhombeus and Mugil sp.) from the estuary, commonly used as food sources by local populations.ResultsOur results revealed high trace metal concentrations in estuarine sediments, when compared to published baseline values for the same estuary. The demersal fish species C. spixii and G. genidens had the highest concentrations of As, Cr, Mn, Hg, and Se in both, hepatic and muscle, tissues. Trace metal bioaccumulation in fish was correlated with the biosynthesis of metallothionein and reduced glutathione in both, liver and muscle, tissues, suggesting active physiological responses to contamination sources. The trace metal concentrations determined in fish tissues were also present in the estuarine sediments at the time of this study. Some elements had concentrations above the maximum permissible limits for human consumption in fish muscles (e.g., As, Cr, Mn, Se and Zn), suggesting potential human health risks that require further studies. Our study supports the high biogeochemical mobility of toxic elements between sediments and the bottom-dwelling biota in estuarine ecosystems.

Health risk assessment and bioaccumulation of toxic metals in commercially important finfish and shellfish resources collected from Tuticorin coast of Gulf of Mannar, Southeastern India

The present study was mainly focused on the distribution of metals (Cd, Cu, Pb, and Zn) in commercially important marine finfish and shellfish resources collected from the Tuticorin coast of the Gulf of Mannar, Southeastern India. Sixty-six species were collected in all four seasons for the analysis of metals. The order of bioaccumulation of metals in fishes is (Zn > Pb > Cu > Cd), in Crustaceans is (Zn > Pb > Cu > Cd), and in mollusks is (Pb > Zn > Cu > Cd). The human health risk assessment factors such as BCF, THQ, and HI were higher in most of the tested animals. The outcome of the present study will sound the alarm to the community about heavy metal contamination of sea foods. We conclude that continuous monitoring of the ecosystem is essential to the maintenance of the pristine ecosystem and quality of the seafood.

Bioaccumulation of Metals in Fishes’ Scales – A Reliable Non-Lethal Assessor of Food Security

Bioaccumulation of Metals in Fishes’ Scales – A Reliable Non-Lethal Assessor of Food Security

Bioaccumulation of Metals in Fish from Sarikum Lake

Concentrations of five heavy metals (Hg, Cd, Pb, Cu and Zn) in edible tissues of four fish species (Cyprinus carpio, Platichthys flesus, Liza aurata, Mugil cephalus) collected from Natural Reserve Area called Sarikum Lake were determined by ICP-MS (Agilent 7700x). The order of heavy metal concentration was observed as: Zn&gt; Cu &gt; Hg &gt; Pb &gt; Cd. The heavy metal levels were species specific and significantly different. The highest concentrations of Hg, Cd and Zn were found in flathead grey mullet, European flounder and common carp, respectively. The higher concentrations of Pb and Cu are present in golden grey mullet. The concentrations of Cd are in range of 0.019-0.027 µg g-1 in common carp, 0.028–0.040 µg g-1 in European flounder, 0.020-0.034 µg g-1 in golden grey mullet and 0.16-0.27 µg g-1 in flathead grey mullet tissues. Concentration of Cd in M. cephalus was limit value and precautions need to be taken in order to prevent future heavy metal contamination, but other metals were lower than those in certified values. Keywords: Cyprinus carpio, Platichthys flesus, Liza aurata, Mugil cephalus, Sarikum Lake

Ecosystem and human health assessment in relation to aquatic environment pollution by heavy metals: case study of the Murmansk region, northwest of the Kola Peninsula, Russia

Throughout the Euro-Arctic region of Russia (Murmansk region), there is a substantial increase of metal concentrations in water, which are related to local discharges from the metallurgical and mining industry, transboundary pollution, as well as indirect leaching of elements by acid precipitation. This study collates data to investigate the relationship between surface water contamination by metals, and fish and human health. Fish are used as a biological indicator to show the impact of water pollution by metals on the ecosystem’s health. The etiology of fish and human diseases are related to the water pollution and accumulation of metals in organisms. High concentrations of Ni and Cd in water drives an accumulation of these elements in organs and tissues of fish, especially in kidneys. The relation between the accumulation of Ni in kidneys and the development of fish nephrocalcinosis and fibroelastosis was established. Statistical analysis demonstrated that human populations in cities close in proximity to smelters show the highest incidence of disease. The results of histological, clinical, and post-mortem examination of patients shows the highest content of toxic metals, especially Cd, in livers and kidneys. Our complex investigation of a set of disorders observed in fish and human populations indicates that there is a high probability that the negative impact on human health is caused by prolonged water contamination by heavy metals. As a novel finding, this paper shows that based on the similarity of pathological processes and bioaccumulation of metals in fish and humans, examining the content of heavy metals in fish can be used to confirm etiology and evaluate the potential risk to human health by pollution of surface waters.

Metal concentrations in fillet and gill of parrotfish (Scarus ghobban) from the Persian Gulf and implications for human health

Despite the benefits of seafood's consumption, the bioaccumulation of metals in fish can endanger consumers' health. This study analyzed lead (Pb), mercury (Hg), Arsenic (As), and Cadmium (Cd) concentrations in fillet and gill of parrotfish (Scarus ghobban) using flame atomic adsorption spectroscopy (FAAS). The potential non-carcinogenic and carcinogenic health risks due to consumption of Scarus ghobban fillet were assessed by estimating average target hazard quotient (THQ) and total target hazard quotient (TTHQ) and Incremental Lifetime Cancer Risk cancer risk (ILCR) of the analyzed metals. This study indicated that Cd, Pb, As and Hg concentrations were significantly (p < 0.05) lower than Food and Agriculture Organization (FAO) and national standard limits. The meal concentrations (μg/kg dry weight) in both fillet and gill were ranked as follows Pb > Cd > As > Hg. THQ and TTHQ were lower than 1 for adults and children, indicating that consumers were not at considerable non-carcinogenic risk. However, ILCR value for As was greater than 10−4, indicating that consumers are at carcinogenic risk. Overall, this research highlighted that although the consumption of parrotfish from the Persian Gulf does not pose non-carcinogenic health risks, carcinogenic risks derived from toxic As can be detrimental for local consumers.

Bioaccumulation of mercury and other metal contaminants in invasive lionfish (Pterois volitans/miles) from Curaçao

A wide range of ecological and environmental factors influence metal bioaccumulation in fish. Studies of mercury and other metal contaminants in invasive Indo-Pacific lionfish are limited, yet consumption of the invasive predator is increasingly utilized as a management strategy. In this study, we examined the effects of body size, body condition, sex, trophic level, carbon source, diet, depth and capture location on mercury concentrations in lionfish collected from Curaçao. In addition, we examined whether or not a local petroleum refinery is the source of metal contamination in lionfish. Mercury concentrations ranged from 0.008 to 0.106 mg/kg and we found no effect of the petroleum refinery on metal bioaccumulation in lionfish. Low concentrations of metal contaminants indicate lionfish from Curaçao are safe for human consumption.

Arsenic, cadmium and lead in fresh and processed tuna marketed in Galicia (NW Spain): Risk assessment of dietary exposure

Currently, metal bioaccumulation in fish is increasing and is a cause of concern due to toxicity. Total arsenic, cadmium and lead concentrations in fresh and processed tuna (110 samples) marketed in Galicia (NW Spain) were determined by ICP-MS spectrometry. The average concentrations of As and Cd, 3.78 and 0.024 mg kg−1 w.w., respectively, in fresh tuna were statistically significantly higher than those in processed tuna (p < 0.001). The contents in processed tuna were 0.295–7.85 mg kg−1 for As and ND-0.045 mg kg−1 for Cd. The Pb content was negligible in both types of tuna. In canned tuna, decreasing As and Cd concentrations were observed in different preparation-packaging media: olive oil > natural > pickled sauce. Of the two species studied in canned tuna, Thunnus alalunga showed statistically significant higher levels both for As 1.28 mg kg−1 (p < 0.001) and Pb 0.013 mg kg−1 (p = 0.0496) than Thunnus albacares. No samples surpassed the limits set by the EU for Cd and Pb. The limit for As in fish has not been established, but the arsenic contents in fresh tuna reported here are important, as they are among the highest reported in the literature. Considering public health in children and adults with respect to the investigated metals, the estimated daily intakes (EDIs) did not exceed the tolerable intakes. No chronic systemic risk was found since all the target hazard quotients (THQs-TTHQs) were far below 1 (critical value), and the carcinogenic risk (CR) for As did not exceed the acceptable value of 10−5. Thus, tuna consumption in the Galician diet does not pose a risk for different population groups in terms of these studied metals/metalloids.

In situ monitoring of the Sinos River, southern Brazil: water quality parameters, biomarkers, and metal bioaccumulation in fish.

The Sinos River is an important water supply in Southern Brazil and receives industrial, agricultural, and domestic effluents which may affect aquatic biota. Water physicochemical and microbiological analyses, biomarker responses (scaled mass index (SMI), gill histopathology, and micronucleus and nuclear abnormality (MN and NA) frequencies), and metal bioaccumulation in muscle were assessed in the fish species Bryconamericus iheringii (Characidae) captured at three sampling sites (S1, S2, and S3) in four sampling periods. The mean values of five parameters (total phosphorus, thermotolerant coliforms, aluminum, iron, and lead) exceeded the limits established by the Brazilian legislation at the three sampling sites. Although physicochemical analysis indicated higher impacts at S3, in some samples, significantly higher MN frequencies and bioaccumulation of manganese in fish muscle were observed at S1, whereas low SMI and higher concentrations of aluminum and zinc in fish muscle were found at S2. Histopathological alterations in gills were observed in fish collected at the three sampling sites; however, no spatial differences were observed, indicating similar environmental conditions with respect to this biomarker. Moreover, temporal variation of biomarker responses and metal bioaccumulation were found at all sampling sites. Furthermore, the consumption of fish from the Sinos River should be avoided given the concentrations of chromium (all samples), cadmium, and lead in fish muscle above the threshold for safe human consumption.

Heavy Metal Levels in Fish from Heilongjiang River and Potential Health Risk Assessment.

Concentrations of Cu, Zn, Cr, As, Cd, Pb and Hg were determined in 153 samples covering 18 fish species collected from Heilongjiang River, China, and the potential health risks to local residents through fish consumption were estimated. Results revealed that all metals were detected with Cd and Pb having considerably lower detection rate. There were 28.6% of Lethenteron camtschaticum samples exceeding the limit of inorganic As content established by Chinese legislation. Metal bioaccumulation in fish were poorly correlated with fish sizes, and generally tended to increase with trophic levels. The hazard quotient values of all fish species were far below 1 for general population and fishermen. The carcinogenic risk of As in L. camtschaticum for the local fishermen exceeded the acceptable level of 10(-4) rise in cancer rates, but was considered safe given the migratory habits of the fish.

Metal bioavailability in freshwater sediment samples and their influence on ecological status of river basins

The general aim of this work has been to check the ecological impact of metals on the Ebro river basin. In order to evaluate this, metal behavior considering water, sediment as well as metal bioaccumulation in fish has been studied. Total concentrations of metals, as well as the potentially bioavailable fraction of metals in sediment has also been analyzed by the application of the sequential extraction method (BCR method). In order to evaluate the influence of metal pollution on the river ecological status, according to the Water Framework Directive (WFD), diverse biological indices such as macroinvertebrates (IBMWP), diatoms (IPS) and macrophytes (IVAM), have been considered from an integrated point of view. Considering both water and sediment, metals which contributed in higher extend to the reduction of biological quality have been demonstrated to be Pb and Zn, as they presented a negative influence on macroinvertebrates, diatoms and macrophytes communities. As and Cr that seemed to have a significant influence on macroinvertebrates and diatoms too, while Ni negatively influenced only diatom communities. This study also demonstrated that monitoring programs only based on total metal determination in water are inefficient, as metals present even at undetectable concentrations in water are strongly accumulated in fish. Moreover, the high concentrations of Hg found in sediments indicated that this river basin may present pollution problems regarded to this metal, as demonstrated by the high Hg levels found in fish.