The case for a cause-effect linkage between environmental contamination and development in eggs of the common snapping turtle (Chelydra S.serpentina) from Ontario, Canada

Concentrations of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins, and dibenzofurans, organochlorine pesticides, and their metabolites were measured in eggs of the common snapping turtle (Chelydra s.serpentina) collected from four wetlands on the shorelines of Lakes Ontario, and Erie, and one control location in central Ontario, Canada. Snapping turtle eggs from these sites were also artificially incubated to determine hatching success, and incidence of deformities in embryo and hatchling turtles. The hypothesis that elevated incidences of egg death and/or deformities of hatchling turtles would occur in populations with high concentrations of organochlorine contaminants in eggs was tested. The results were elevated using epidemiological criteria. Unhatched eggs and deformities occurred at significantly higher rates in eggs from Lake Ontario wetlands. Two of three sites from Lake Ontario had substantially higher levels of PCBs, dioxins, and furans compared to eggs from Lake Erie and the control site. It could not be shown that contamination of eggs preceded the occurrence of poor development of eggs, although excellent hatching success and low numbers of deformities in eggs from the control site were considered representative of development in healthy eggs. The statistical association between contaminant levels in eggs and poor development of these eggs supported the hypothesis that eggs from sites with the greatest contamination had the highest rates of abnormalities. PCBs were the most strongly associated chemicals, although possible effects due to the presence of other chemicals in eggs was a confounding factor. The deformities and rates of unhatched eggs were similar to those occurring in other vertebrates collected from highly contaminated areas of the Great Lakes. There were several chemicals present in the eggs that can cause similar reproductive effects in other species; therefore a specific chemical effect was not identified. Results were coherent with known statistical and biological information. Theoretical and factual evidence of PCB contamination in wild-caught snapping turtles supported and hypothesis. However, lack of controlled studies of reproductive effects of polychlorinated hydrocarbons upon this species hindered the agreement of all factual and theoretical evidence with the hypothesis.     

Levels of heavy metals in biota from the la plata river

In this study levels of five heavy metals—Cd, Cu, Ni, Pb, and Zn—were quantified in selected tissues of aquatic organisms and in sediments from the La Plata River. Fishes (Odontesthes bonariensis and Pimelodus clarias), snails (Ampullaria insularum), and bivalve molluscs (Neocorbicula limosa) were collected from a Recreational Fishing Association, nearby Buenos Aires harbor, during 1988 and 1989. Samples of snail hepatopancreas showed higher levels of metal concentrations than samples of fish livers, regarding the five metals quantified. In general, lower levels of heavy metals were observed in whole body samples of bivalves, with or without the gut contents, except for Cd. Both species of macroinvertebrates have demonstrated a great ability to bioaccumulate Cd. Many physical, chemical, and biological factors regulate the intake and accumulation of heavy metals by aquatic organisms. Therefore, it is difficult to assess the extent of pollution in biota from the La Plata River by direct comparisons with data previously reported in the literature. However, our results may be useful as reference levels of heavy metal contamination in selected organisms from this particular aquatic system. © 1993 John Wiley & Sons, Inc.     

Determination of heavy metals in albumen of hen eggs from the Markazi Province (Iran) using ICP-OES technique

Increase of distribution of environmental contaminants such as heavy metals have been caused the knowledge of the safety and hygiene of food is very important, especially eggs, because of its role in the daily diet. There are very few studies about the investigation of the heavy metal contents in egg-white. In this study, six heavy metals include Aluminium (Al), Arsenic (As), Lead (Pb), Cadmium (Cd), Mercury (Hg), Antimony (Sb) in egg-white from 32 industrial poultry farms were investigated, by ICP-OES. All the samples were collected in all area of Markazi Province, Iran in autumn 2013. The mean concentrations of heavy metals in egg-white as follows: 0.119 for Al, 0.785 for As, 0.750 for Pb, 0.249 for Cd, 0.270 for Hg and 0.186?mg/kg for Sb. Also, the concentration of the some heavy metals were higher than maximum allowable concentration that probably it is associated to use pesticides and activities of industrial factories around the poultry farms.     

Heavy metals levels in fish from aquaculture farms and risk assessment in Lhasa,Tibetan Autonomous Region of China

Fish is consumed as a common food by humans due to its nutritional and therapeutic benefits. However, they can accumulate toxic chemicals (such as heavy metals, persistent organic pollutants) from water and food chain. Very few studies have been investigated on heavy metal contents in fish from Tibetan Autonomous Region of China. In order to study heavy metals levels in fish from aquaculture farms and evaluate the risk that human consume fish in this area, we collected four types of aquaculture fish species (6 big-head carps, 5 grass carps, 5 carps and 5 tilapias) from fisheries around Lhasa city in this study. 9 heavy metals (Cr, As, Cd, Pb, Cu, Ba, Co, Mn and V) in different tissues of fish were determined by an inductively coupled plasma mass spectrometer. Cr, Ba, Co, Mn and V could easily accumulate in the gill, and Cu was detected in the hearts of all the fishes. Toxic metal (As, Cd and Pb) contents were higher in the liver than those in other tissues, heavy metal levels were the lowest in the muscle among all tissues. Most of heavy metal concentrations in the tilapia tissues were higher than those in other fish tissues, especially arsenic. Arsenic content in the tilapia samples was ~2–4 times higher than the maximum levels (MLs) of contaminants in the national standard, and other metals were all lower than the MLs. Compared the estimated daily intake of heavy metals through fish consumption with tolerable daily intakes recommended by FAO, the metals daily intake of As, Cd and Pb from fish consumption might not pose serious health risk to the local inhabitants. It is therefore necessary to determine the dose level for human, which is considered to be taken daily over a lifetime without adverse effects.     

Distribution characteristics and ecological risk assessment of toxic heavy metals and metalloid in surface water of lakes in Daqing Heilongjiang Province,China

It is necessary to estimate heavy metal concentrations and risk in surface water for understanding the heavy metal contaminations and for sustainable protection of ecosystems and human health. To investigate the anthropogenic contribution of heavy metal accumulation surrounding an industrial city in China, the concentrations of six heavy metals, including mercury (Hg), arsenic (As), chromium (Cr), lead (Pb), copper (Cu), and cadmium (Cd) were examined; from four different regions of Daqing in autumn 2011 and winter 2012. The results showed heavy metals distributed in the industrial area at concentrations relatively higher than those in other three areas, while concentrations in the farming area and the protected area were lower. The heavy metal concentrations of water bodies in all areas, except those for Hg and As, Cu, Pb and Cr were lower than the cutoff values for the Class I water quality that was set as the highest standard to protect the national nature reserves. While Hg and As of lakes in industry region had a higher level than those in the agriculture and landscape water, the lowest allowed. The concentrations of all the heavy metals in winter were higher than in the autumn. Cu had a higher ecological risks level to freshwater organisms. The discharge of urban sewage and industrial wastewater might be a major pollutant source, thus these sources should identified before remediation efforts. Efforts are needed to protect the lakes from pollution and also to reduce environmental health risks. This study and the valuable data will pave the way for future research on these Lakes in Daqing.     

Assessing the ecotoxicological effects of long-term contaminated mine soils on plants and earthworms: relevance of soil (total and available) and body concentrations

The interactions and relevance of the soil (total and available) concentrations, accumulation, and acute toxicity of several essential and non-essential trace elements were investigated to determine their importance in environmental soil assessment. Three plant species (T. aestivum, R. sativum, and V. sativa) and E. fetida were simultaneously exposed for 21 days to long-term contaminated soils collected from the surroundings of an abandoned pyrite mine. The soils presented different levels of As and metals, mainly Zn and Cu, and were tested at different soil concentrations [12.5, 25, 50, and 100 % of contaminated soil/soil (w/w)] to increase the range of total and available soil concentrations necessary for the study. The total concentrations in the soils (of both As and metals) were better predictors of earthworm uptake than were the available concentrations. In plants, the accumulation of metals was related to the available concentrations of Zn and Cu, which could indicate that plants and earthworms accumulate elements from different pools of soil contaminants. Moreover, Zn and Cu, which are essential elements, showed controlled uptake at low concentrations. The external metal concentrations predicted earthworm mortality, whereas in plants, the effects on growth were correlated to the As and metal contents in the plants. In general, the bioaccumulation factors were lower at higher exposure levels, which implies the existence of auto-regulation in the uptake of both essential and non-essential elements by plants and earthworms.     

Chromosomal Damage in Two Species of Aquatic Turtles (<Emphasis Type="Italic">Emys orbicularis</Emphasis> and <Emphasis Type="Italic">Mauremys caspica</Emphasis>) Inhabiting Contaminated Sites in Azerbaijan

The Caspian region and specifically the Apsheron peninsula of Azerbaijan are known to be polluted with a variety of environmental contaminants. These complex mixtures of contaminants make risk assessment difficult. We used the flow cytometry method (FCM) and the micronucleus assay (MN) to assess chromosomal damage in aquatic turtles (Emys orbicularis, the European pond turtle; and Mauremys caspica, the Caspian turtle) inhabiting contaminated wetlands in Azerbaijan. Evidence of genetic damage was found for two sites, Neftchala and Sumgayit, relative to a reference site, Ali Bairamly. Sediment samples from each site were analyzed for PAHs and mercury to evaluate potential contaminant associations with genetic damage. A significant positive correlation was documented between three-ring PAH sediment concentrations and FCM estimates of chromosomal damage in E. orbicularis. These data combine to show that the contaminated wetlands in Sumgayit and Neftchala are genotoxic and that three-ring PAHs are likely a significant influence on observed genotoxicity.     

Maternal transfer of trace elements in leatherback turtles (Dermochelys coriacea) of French Guiana

In sea turtles, parental investment is limited to the nutrients and energy invested in eggs that will support embryonic development. Leatherback females have the largest clutches with the biggest eggs of the sea turtles and the highest reproductive output in reptiles. The migration between foraging sites and nesting beaches also represents high energy expenditure. The toxicokinetic of pollutants in the tissues is thus expected to vary during those periods but there is a lack of information in reptiles. Concentrations of essential (Copper, Zinc, Selenium) and non-essentials elements (Cadmium, Lead, Mercury) were determined in blood (n=78) and eggs (n=76) of 46 free-ranging leatherback females collected in French Guiana. Maternal transfer to eggs and relationships between blood and eggs concentrations during the nesting season were investigated. All trace elements were detectable in both tissues. Levels of toxic metals were lower than essential elements likely due to the high pelagic nature of leatherbacks that seems to limit exposure to toxic elements. Significant relationships between blood and egg concentrations were observed for Se and Cd. Se could have an important role in embryonic development of leatherback turtles and Cd transfer could be linked to similar carrier proteins as Se. Finally, as multiple clutches were sampled from each female, trends in trace elements were investigated along the nesting season. No change was observed in eggs but changes were recorded in blood concentrations of Cu. Cu level decreased while blood Pb levels increased through the nesting season. The high demand on the body during the breeding season seems to affect blood Cu concentrations. Calcium requirement for egg production with concomitant Pb mobilization could explain the increase in blood Pb concentrations along the nesting season.     

Metal bioaccumulation and its genotoxic effects on eggs and hatchlings of giant Amazon river turtle (Podocnemis expansa)

The aim of this study was to assess whether possible metal contamination in the sediment of the nests of giant Amazon river turtle, Podocnemis expansa, could contaminate eggs and hatchlings, triggering genotoxic damage. Therefore, sediments of P. expansa nests from two sites in the Brazilian Amazon were evaluated, with the first being collected at Araguaia River and the second at Crixás-Açu River. Newly hatched offspring, eggs, and sediments were collected from the beaches of these two rivers and the quantification of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) was carried out by atomic absorption spectroscopy. All targeted metals were found in both sediment and P. expansa biological samples collected on the beaches presenting higher concentrations in the sediment of Crixás-Açu River. Metals found in the eggshells before nesting and in the egg contents were maternally transferred. Moreover, augmented concentration of metals led by metal transfer from the nests sediments were detected in the eggshells after nesting (ENH) and in the newly hatched offspring (H). Probably this metal relocation to the newly hatchlings augmented the frequency of micronuclei in their blood, presenting 15.25‰ in hatchling found in Crixás-Açu River beaches and 10‰ in newly hatched animals from Araguaia River beaches. These results indicate the occurrence of maternal transfer of metals (essential or not) to the eggs in testudines as well as a transference from the sediments to the nesting eggs, triggering genotoxic effects on the hatchlings.

     

Industrial pollution with copper and other heavy metals in a beef cattle ranch

Experimental evidence of air borne heavy metal pollution as the cause of a disease of unknown etiology in beef cattle was obtained. Analysis of metals in natural grasses and leaves of tree defined Cu, Zn and Pb as the major pollutants, with Cd being a minor one. Emissions from a Cu smelter were traced as the main source of metallic pollution. No evidence of metal accumulation in the soil was found, mainly because of the short duration and intermittent pattern of pollution. A progressive intake of the several heavy metals contained in dusts deposited on the grasses was considered the cause of the sickness; this was associated with the grazing of cattle on contaminated grasses. The most severe cases were found in the most polluted pastures. Excepting Cd, the concentrations of the metals in the livers and kidneys of affected cattle were high. No overlapping of the respective ranges between test and control samples from both organs was found. Mean hepatic levels of Cu (925.7 mg/kg DM), Zn (491.2 mg/kg) and Pb (26.7 mg/kg) reflected the decreasing order of the concentrations of these elements in the polluted grasses. The main clinical and pathological features of this disease were discussed in light of the organic levels of the investigated metals. Disease could not be ascribed to a pure chronic toxicosis with any one of these.     

Accumulation of Trace Elements by <Emphasis Type="Italic">Pistia stratiotes</Emphasis>: Implications for phytoremediation

The toxicity of eight potentially toxic trace elements (Ag, Cd, Cr, Cu, Hg, Ni, Pb and Zn) to Pistia stratiotes was examined to determine if this plant showed sufficient tolerance and metal accumulation to be used to phytoremediate waste water and/or natural water bodies polluted with these heavy metals. Young plants of equal size were grown hydroponically and amended with 0, 0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 mM of each heavy metal individually for 21 days. Root elongation as well as emergence of new roots decreased significantly with increase in metal concentrations. The plant had the lowest and the highest tolerance indices for Hg and Zn respectively. The study indicated reduction in the rate of leaf expansion relative to metal type, their concentrations and the duration of exposure. A significant reduction in biomass production was observed in metal treated plants compared with the control plants. The relative growth rate of P. stratiotes was retarded by heavy metals under study. All trace elements accumulated to higher concentrations in root tissue rather than in shoot. Trace element accumulation in tissues and the bioconcentration factors were proportional to the initial concentration of individual metals in the growth medium and the duration of exposure. In terms of trace element removal, P. stratiotes presented differential accumulation and tolerance levels for different metals at similar treatment conditions. The implications of these results for phytoremediation are discussed.     

Vitellogenin induction in painted turtle, Chrysemys picta, as a biomarker of exposure to environmental levels of estradiol

Ponds within cattle farms often support turtle and fish populations and are impacted by manure runoff. Cattle excrete metabolized (glucuronide-conjugated) hormones in feces and urine into these ponds, and bacteria cleave the glucuronide metabolites to active steroids, which can be stable for several weeks in wastewater. The objectives of this study were to (1) assess levels of xenoestrogens found in ponds near livestock pastures; and (2) assess whether these levels of xenoestrogens induce vitellogenin (VTG) in painted turtles in the laboratory and field. We collected water twice, 6 weeks apart, and placed turtle traps weekly into two ponds, which receive runoff from beef cattle pastures, and into one pond with no cattle farm effluents. Water E(2) levels were analyzed using C(18) solid phase extraction disks and detected in a radioimmunoassay (RIA). Plasma was collected from painted turtles (Chrysemys picta) captured from these ponds and VTG levels were measured via enzyme linked immunosorbent assay (ELISA). Nine additional turtles were collected from a pond at the South Carolina Botanical Gardens, which receives no farm runoff, and were exposed in the laboratory to nominal concentrations of 0.15, 1.5, and 15 ng/l estradiol (static renewal) over a 28-day period, followed by 14 days in clean water. Plasma samples were taken weekly for VTG measurement via ELISA. Levels of free estradiol in the water column of farm ponds range from 0.05 to 1.80 ng/l, as measured by RIA, and up to 7.4 ng/l as measured by ER-beta binding affinity. This is similar to what has been reported in streams receiving sewage treatment works (STW) effluents. In the laboratory, plasma VTG in male painted turtles could not be induced even at the high E(2) dose (9.45 ng/l) after 28 days. In the field, VTG levels were induced only in females when compared with animals from the SC Botanical Gardens. Adult male turtles need to be primed with high doses of E(2) prior to being able to respond to exogenous E(2). Given that males would not typically be sensitized in the wild, environmentally relevant levels of E(2) may not be sufficient to affect them. However, higher VTG levels in females could potentially change their reproductive fitness by altering egg size or by shifting energy allocations away from other survival needs. Long-term studies are needed to study potential impacts of VTG induction on female turtle reproductive success.     

Health risk assessment of heavy metals via dietary intake of foodstuffs from the wastewater irrigated site of a dry tropical area of India

The present study was conducted to assess the risk to human health by heavy metals (Cd, Cu, Pb, Zn, Ni and Cr) through the intake of locally grown vegetables, cereal crops and milk from wastewater irrigated site. Milk is not directly contaminated due to wastewater irrigation, but is an important route of food chain transfer of heavy metals from grass to animals. Heavy metal concentrations were several fold higher in all the collected samples from wastewater irrigated site compared to clean water irrigated ones. Cd, Pb and Ni concentrations were above the ‘safe’ limits of Indian and WHO/FAO standards in all the vegetables and cereals, but within the permissible limits in milk samples. The higher values of metal pollution index and health risk index indicated heavy metal contamination in the wastewater irrigated site that presented a significant threat of negative impact on human health. Rice and wheat grains contained less heavy metals as compared to the vegetables, but health risk was greater due to higher contribution of cereals in the diet. The study suggests that wastewater irrigation led to accumulation of heavy metals in food stuff causing potential health risks to consumers.     

Using an Integrated Approach to Assess the Sediment Quality of an Mediterranean Lagoon,the Bizerte Lagoon (Tunisia)

The present study investigates the quality of surface sediments from the Bizerte lagoon (North Tunisia) using an integrated approach including chemical contaminant analysis, bioassays and sediment quality guidelines (SQGs). Sediment samples were collected at 9 sites and analyzed for eight heavy metals (Hg, Cd, Cr, Cu, Pb, Zn, Ni, Fe and Mn). PAHs, PCBs, OCPs were measured previously in the same sediment samples. Our results indicated that the highest concentrations of metals were found near urban areas due to the municipial and industrial wastewater discharges. Sediment pollution assessment was carried out using geoaccumulation index and enrichment factor, which indicate a widespread pollution by Cd, Pb, Ni and Zn in the studied sediments. For bioassays, aqueous and organic extracts were used to assess toxicity and genotoxicity in sediments by using Microtox^® and SOS Chromotest, respectively. Toxicity levels were compared to metallic and organic pollutants contents. Our results highlight differences in the pattern of responses between the different assays and show no correlation with all the studied contaminants, emphasizing the influence of other contaminants not analyzed in the present study. Based on SQGs, the results of toxicity assessment indicated that adverse effects caused by Ni and Zn would be expected frequently. Nickel was found to have the highest predicted acute toxicity, followed by Zn, Pb, Cd, Cu and Cr. There was no significant relationship between sediment toxicity calculated from heavy metal concentrations (SQG approach) and those measured with bioassays. These findings support the use of integrated approachs for evaluating the environmental risks of sediments.     

Effect of heavy metals on the antioxidant enzymes in the marine ciliate Euplotes crassus

A single-cell eukaryote, Euplotes crassus is considered as a suitable model species to evaluate the effect of environmental contaminants particularly in sedimentary aquatic environments. Here, we investigated the effect of heavy metals (Cu, Pb and Zn) on the population growth and the gene expression of antioxidant enzyme coding genes (Ec-GR, Ec-GPx, and Ec-GSTtheta) in E. crassus. As a result, heavy metals negatively affected population growth measured as the 48-h EC₅₀ values as 1.58 mg/L for Cu, 4.13 mg/L for Pb, and 4.97 mg/L for Zn. Copper and zinc significantly increased the expression of Ec-GR, Ec-GPx, and Ec-GST-theta, suggesting that these genes may be involved in protection mechanisms against oxidative stress induced by Cu and Zn. Interestingly, Pb exposure inhibited the expression of all genes, indicating that these genes may be effective molecular biomarkers to evaluate toxic effects of heavy metals in this species.     

Aquatic insects and trace metals: bioavailability, bioaccumulation, and toxicity.

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physicochemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Effects of lipophilic complex formation on the uptake and distribution of some metals in fish

Dithiocarbamates, xanthates, dialkyldithiophosphates and pyridinethiones are groups of compounds which can form lipophilic complexes with heavy metals. These compounds are widely used in industry and in agriculture and forestry and may pollute the aquatic environment. We have exposed fish (brown trouts) to substances belonging to these groups of compounds together with heavy metals (Cd2+, Ni2+, Hg2+, CH3-Hg+ or Pb2+) and then examined the uptake of the metals in the tissues of the fishes. Some of the examined complexing substances were found to cause highly increased tissue levels of the metals in the trouts. However, the enhancing effects varied for different complexing substances and for different metals. A facilitated penetration of the lipophilic complexes over the gill membranes and cellular membranes in other tissues may underlie the increments in the tissue levels of the metals. The lipophilicity and the stability of the complexes may be of importance for the effects of the substances on the disposition of the metals. Studies by other authors, in fishes as well as in other aquatic organisms, have also shown enhanced metal accumulation by compounds forming lipophilic complexes. It is considered that this type of interaction may have important implications for the behaviour of metals in aquatic ecosystems.     

Chemical Contaminants and their Effects in Fish and Wildlife from the Industrial Zone of Sumgayit, Republic of Azerbaijan

Sediment from a wetland adjacent to an industrial wastewater treatment plant in Sumgayit contained concentrations of total PAHs, total PCBs, aldrin, biphenyl, chlordane, DDT, mercury, beta-endosulfan, heptachlor, alpha-hexacyclohexane (alpha-HCH), gamma-HCH, and several individual PAH congeners that were elevated relative to published sediment quality guidelines. Chemical analyses of tissues from European pond turtles (Emys orbicularis) had increased levels of many of the same chemicals including aldrin, chlordane, heptachlor, alpha-HCH, total PCBs, total PAHs, and mercury, compared to reference turtles. In addition, turtle tissues contained elevated levels of DDD, hexachlorobenzene (HCB), and pentachlorobenzene that were not elevated in the sediment sample. Some differences were observed in contaminant levels between European pond turtles and Caspian turtles (Mauremys caspica) taken from the ponds in Sumgayit. Salmonella/microsome mutagenicity assays on pond sediments were negative or weakly positive. Micronuclei in European pond turtles were statistically correlated with tissue levels of mercury, heptachlor, DDD, HCB, and trans-nonachlor. Microcosm experiments using Russian sturgeon (Acipenser gueldenstaedtii) showed a positive dose-response relationship between exposure to suspended contaminated pond sediment and acute toxicity. Chemical and biological assays used in this study show the industrial area of Sumgayit is heavily contaminated with a complex mixture of toxic pollutants. Exposure to contaminated sediments produced acute effects in Russian sturgeon, but genotoxic effects appear to be slight.