Metal levels in sediments and transplanted mussels in Pagassitikos Gulf (Aegean Sea, Eastern Mediterranean)

Metal concentrations were determined in surface sediments and transplanted mussels in a shallow semi-enclosed bay, Pagassitikos Gulf, Aegean Sea. Cu, Zn, Pb, Hg, and As levels in sediments were enriched close to point sources of pollution, i.e., Volos Port and cement plant. Fe, Mn, Cr, and Ni spatial distributions in sediments were rather uniform with increasing concentrations towards deeper sites, suggesting natural enrichment, whereas levels found in the port, although elevated, were not the highest in the study area. Spatial variations in concentrations of most metals in mussels transplanted nearshore were generally in accordance to those in sediments, with the highest Fe, Mn, Cr, Ni, and Cu levels in the port and the highest Hg levels close to the cement plant. Concentrations of metals in sediments and transplanted mussels were comparable to those reported in Mediterranean areas. Results indicate that pollution point sources contribute to anthropogenic metal enrichment in the study area.     

Metal concentrations in water, sediment, and fish from sewage-fed aquaculture ponds of Kolkata, India

The concentrations of lead, cadmium, chromium, copper, and zinc were investigated in the sewage-fed pond water, sediment, and the various organs of Labeo rohita, Catla catla, Cirrhinus mrigala, Oreochromis mossambicus, and Cyprinus carpio cultured in sewage-fed ponds, Kolkata, India. Among the metals, cadmium, lead, and zinc were detected in water and, except lead, were below the water quality guideline levels for the protection of freshwater aquatic life proposed by CEQG (Canadian Environmental Quality Guidelines) and AENV (Alberta Environment). Therefore, lead could pose danger to aquatic organisms. All the five metals were detected in the sediment and, except cadmium and lead, were below the sediment quality guideline levels for aquatic life proposed by EPA (Environmental Protection Agency). Therefore, these two metals could be toxic to aquatic organisms. Significant (P > 0.05) differences were observed among the five fish species for all these metals accumulation. Also, significant (P > 0.05) differences were noticed among these metals accumulation in fish organs. Cadmium showed the least bioaccumulation, while zinc showed the highest bioaccumulation in all the fish species. Though the metal concentration in the different fish tissues was variable, the highest concentration was found in kidney and the lowest in the muscle. Concentrations of these metals in the muscle tissue of all the fish species were well below the consumption safety tolerance in fish set by WHO/FAO, and thus, so far as these metals are concerned, these sewage-fed cultured fishes are safe and suitable for human consumption.     

Contaminant concentrations in whole-body fish and shellfish from US estuaries

Persistent bioaccumulative and toxic (PBT) pollutants are chemical contaminants that pose risks to ecosystems and human health. For these reasons, available tissue contaminant data from the US EPA Environmental Monitoring and Assessment Program’s National Coastal Assessment were examined to estimate to what areal extent PBTs are found in US estuarine resources. The data document composite, whole-body tissue chemical concentrations for 736 sampling sites across Northeast, Southeast, Gulf of Mexico, and West Coast estuaries. Tissue chemical concentrations were compared to US EPA non-cancer risk guidelines for recreational fishers, because of a lack of ecological guidelines for these chemical concentrations. Samples were analyzed for 23 PAH compounds, 21 PCB congeners, 6 DDT derivatives and metabolites, 14 chlorinated pesticides (other than DDT) and 13 metals, including mercury. Total PCBs were found to exceed recreational fisher guidelines most frequently (31% of samples evaluated), followed by mercury (29%), total PAHs (21%), and DDT and its metabolites, DDD and DDE (11%). Toxaphene, cadmium and dieldrin were found but in fewer than 1% of the samples.     

Metal Concentrations in Fish Species from the Northeast Mediterranean Sea

Samples of Mugil cephalus and Mullus barbatus were collected in the Northeast Mediterranean coast of Turkey the contents of cadmium, copper, iron, zinc and lead in the liver, gill and muscle tissues were determined by atomic absorption flame spectrophotometry.Except for lead, highest levels of each metal were found in the liver and this was followed by the gill and muscle in both species. Among the metals analyzed, Cu, Zn and Fe were the most abundant in the different tissues while Cd and Pb were the least abundant both in M. cephalus and M. barbatus. Seasonal changes in metal (Cd, Cu, Pb, Fe and Zn) concentration were observed in the tissues of both species, but these seasonal variations may not influence consumption advisories. In general, the highest concentrations were detected for all metals in summer.     

Assessment of trace metal concentrations in muscle tissue of certain commercially available fish species from Kayseri,Turkey

Regular consumption of fish has been widely recommended by health authorities. However, it is known that some species accumulate high levels of contaminants including heavy metals (e.g., Hg, Cd, Pb, and As). In this study, Cu, Pb, Co, Ni, Cr, Mn, Cd, and Fe were determined in the muscle tissue of 11 commercially available fish species (Sparus auratus, Dicentrarchus labrax, Mullus barbatus, Belone belone, Psetta maxima, Epinephelus aeneus, Salmothymus, Soleidae, Pomatomus saltatrix, Engraulis encrasicolus, and Sarda sarda) supplied from retailers in Kayseri, Turkey. Determinations were carried out by flame atomic absorption spectrometry after the wet digestion method. The average metal concentrations of the 11 species were determined in the range of 0.54–1.79, 0.82–1.40, 2.38–4.54, 1.23–3.67, 5.01–5.97, 0.77–3.59, 0.48–1.06, and 5.05–122.8 μg/g wet weight for Cu, Pb, Co, Ni, Cr, Mn, Cd, and Fe, respectively. The permissible tolerable daily intake (PTDI) and calculated daily intake (CDI) values were compared, and the calculated daily intake values of the samples were found to be below the established values. Correlations between the metal contents in samples were investigated by performing correlation tests with SPSS 13.0 for windows.     

Metals in tissues of fish from Yelkoma Lagoon, northeastern Mediterranean

This study was performed to investigate the metal concentrations in muscle, liver, gonad, and gill of gilthead seabream (Sparus aurata L., 1758), European seabass (Dicentrarchus labrax L., 1758), and keeled mullet (Liza carinata Valenciennes, 1836) from Yelkoma Lagoon, northeastern Mediterranean region. So, the levels of cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, and zinc in tissues of specimens from the lagoon were determined by inductively coupled plasma optical emission spectrometer. Concentrations of metals in muscles of the examined species ranged from 0.10 to 0.47 mg kg^???1 for cadmium, 0.10 to 0.43 mg kg^???1 for cobalt, 0.17 to 0.72 mg kg^???1 for chromium, 0.62 to 1.03 mg kg^???1 for copper, 28.9 to 52.3 mg kg^???1 for iron, 0.75 to 0.96 mg kg^???1 for manganese, 0.11 to 0.57 mg kg^???1 for nickel, 0.19 to 0.47 mg kg^???1 for lead, and 6.01 to 13.9 mg kg^???1 for zinc, respectively. Additionally, metal concentrations in muscles of fish were assessed for human uses according to provisional tolerable weekly intake and provisional tolerable daily intake.     

Metal concentrations in deciduous tree leaves from urban areas in Poland

Accumulation of metals in deciduous tree foliage fromurban areas in western-south Poland was monitored duringthe vegetation season of 2000 year. Concentrations of Al,Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, Ti and Znwere measured in birch, willow, linden and maple leavesusing the ICP-AES method. Seasonal variations of metalconcentrations and their relations with sampling sitewere investigated. The most dynamic accumulation of Al,Cd, Cr, Ni and Pb was observed for examined species. Thehighest differences in element concentrations forinvestigated sites were found for Ba, Cd, Mn and Ni.Interelement correlations were investigated. In allfoliar samples synergistic relationships between Al–Crand Ca-Sr were found. Statistically significant negativecorrelations were observed only for Cd and Ti in birch leaves.     

Trace Metal Levels in Mussels (Mytilus Galloprovincialis L. 1758) from Turkish Aegean Sea Coast

Bio-monitoring of some heavy metal levels (Cd, Pb, Zn, Cu) in whole edible soft parts of Mytilus galloprovincialis (L. 1758) was conducted in Turkish Aegean Sea coast during the period of September 2002–August 2003 seasonally. Moreover, some physico-chemical environmental parameters, also have been analysed in the same region. The values of some physico-chemical environmental parameters in coastal waters of Turkish Aegean Sea were changed between; 9.0–27.0 ^∘C for temperature, 31.93–40.45 psu for salinity, 7.35–8.48 for pH and 4.05–9.50 mg/l for dissolved oxygen. The levels of trace elements in whole edible soft parts including interstitial fluids of Mediterranean mussels M. galloprovincialis (L. 1758), sampled from 6 different regions of Turkish Aegean Sea coast have ranged between; 0.04–0.52 μg Cd/g wet weight, 0.49–1.72 μg Pb/g w.w., 0.95–1.85 Cu/g w.w., 16.11–37.15 μg Zn/g w.w. The highest values for all trace metals (Cd, Pb, Zn, Cu) were measured in inner part of Izmir Bay (station 3) and lowest in Sigacik and Gulluk Bay (station 5, 6). Generally heavy metal levels are lower than the results in soft mussel tissues reported from Mediterranean regions.     

Impacts of the fish farms on the water column nutrient concentrations and accumulation of heavy metals in the sediments in the eastern Aegean Sea (Turkey)

Pulp and paper mill effluents may cause harmful effects to the aquatic environment due to the combined influence of physical factors, toxic compounds, and nutrient enrichment. In the present study, the effectiveness of secondary treatment in reducing the toxicity of an elemental chlorine-free bleached-kraft pulp mill effluent was evaluated. To characterize the toxicity of the effluent, before and after the implementation of secondary treatment, a battery of tests with organisms bearing different functions at the ecosystem level was used, namely Vibrio fischeri (5-min luminescence), Pseudokirchneriella subcapitata (72-h growth), Lemna minor (7-day growth), Daphnia magna (21-day reproduction and 24-h postexposure feeding), Chironomus riparius (9-day growth), and Danio rerio (28-day growth). For the effluent sample collected before the implementation of secondary treatment, P. subcapitata was the most sensitive organism followed by V. fischeri and D. magna, and no toxic effects were observed toward the other organisms. For the effluent sample collected after the implementation of secondary treatment, the effluent caused no toxic effects on any of the tested species. The present results demonstrated not only that secondary treatment efficaciously reduced effluent toxicity toward the selected test organisms but also the usefulness of a battery of tests to characterize the toxicity of pulp mill effluents.     

Mercury accumulation in fish species from the Persian Gulf and in human hair from fishermen

Total and methylmercury concentrations were assessed in muscle and liver of 141 fish samples from the northern part of the Persian Gulf. All fish samples belonged to five different species: grunt, flathead, greasy grouper, tiger-tooth croaker, and silver pomfret. In addition, Hg and methylmercury were analyzed in scalp hair of 19 fishermen living in the same coastal stations of the Persian Gulf and consuming several fish meals a week. Total mercury concentrations in fish muscle and liver ranged from 0.01 to 1.35 μg g^???1 w.w. and from 0.02 to 1.30 μg g^???1 w.w., respectively. In fish muscle, 3% of the Hg concentrations were higher than 0.5 μg g^???1 w.w., which corresponds to the maximum acceptable WHO level, while 9% were in the range of polluted fish (between 0.3 and 0.5 μg g^???1 w.w.). The highest mercury concentrations in fish muscle were observed in flathead fish at Abadan (average of 0.68 μ g g^???1 w.w.). Methylmercury fractions in fish muscle and liver amount to 34–99% (median 64%) and 24–70% (median 43%), respectively. The mean total Hg concentration in the fishermen’s scalp hair amounted to 2.9 ± 2.2 μ g g^???1, with 68% in the form of methylmercury. Ninety-five percent of the Hg levels in the fishermen’s hair were below 10 μ g g^???1, which is the WHO warning limit. In addition, relationships between the mercury levels in hair, on the one hand, and exposure-related factors such as Hg levels in specific fish species, regional differences, and number of fish meals, on the other hand, are discussed. It appears that a significant correlation for example exists between Hg levels human hair and fish muscle or human hair and age and that mean mercury levels in fish muscle and human hair decreased from western (Abadan) to eastern (Abbas port) coastal sites.     

Baseline survey of concentrations of toxaphene congeners in fish from European waters

The European Union project "Investigation into the monitoring, analysis and toxicity of toxaphene"(MATT) began in 1997 involving participants from the Netherlands, Ireland, Norway and Germany. Concentration information, analytical methodology and statistical interpretation of 207 samples covering 23 different fish species from European waters are presented for three toxaphene indicator congeners: CHBs 26, 50 and 62 (CHB = chlorobornane). Concentrations for the Sigma3CHBs were more elevated in fish from more northern latitudes, such as the Barents and Norwegian Sea, compared to fish from Irish, Dutch and German waters. Concentrations were lowest in shellfish and in fish species having low lipid content and were highest in medium/high lipid species. Females from a number of fish species were shown to contain significantly higher concentrations than those observed in male fish. Overall no samples were shown to exceed existing German MRL legislation, with only one Greenland halibut sample shown to exceed Canadian TDI recommendations.     

Metal and metallothionein concentrations in Paracentrotus lividus from Amvrakikos gulf (Ionian Sea-Greece)

Concentrations of Cd, Cu, Cr, Ni, Zn, Fe and metallothioneins (MTs) were measured in the gonads of Paracentrotus lividus from Amvrakikos gulf (Ionian Sea, Greece). Three natural populations were selected; two of them, growing inside the gulf (Agios Thomas and Koronisia), presented higher density and smaller body size than the population living in a coastal area just outside the gulf (Mytikas). Metal and MT levels were not elevated, with the exception of Zn, showing high values related to the reproduction stage of the sea urchins. Significant geographical variations were recorded in the concentrations of Cu, Zn, Cd, Cr and MTs. The highest mean and maximum values of Cu, Zn and MTs were recorded in Agios Thomas while Cd and Cr were higher in Mytikas population. Copper, Zn, Fe and MT concentrations were negatively correlated to the sea urchin body size, while a positive concentration-size relationship was observed for Cd. Although all studied populations grow in a low metal level marine environment, urchins with smaller body size living in a food limited marine environment showed higher gonadosomatic index, metal concentrations and MT levels in their gonads (Agios Thomas and Koronisia) than larger specimens growing in a food unlimited area (Mytikas).     

Mercury concentrations in fish from a Sierra Nevada foothill reservoir located downstream from historic gold-mining operations

This study examined mercury concentrations in whole fish from Camp Far West Reservoir, an 830-ha reservoir in northern California, USA, located downstream from lands mined for gold during and following the Gold Rush of 1848–1864. Total mercury (reported as dry weight concentrations) was highest in spotted bass (mean, 0.93 μg/g; range, 0.16–4.41 μg/g) and lower in bluegill (mean, 0.45 μg/g; range, 0.22–1.96 μg/g) and threadfin shad (0.44 μg/g; range, 0.21–1.34 μg/g). Spatial patterns for mercury in fish indicated high concentrations upstream in the Bear River arm and generally lower concentrations elsewhere, including downstream near the dam. These findings coincided with patterns exhibited by methylmercury in water and sediment, and suggested that mercury-laden inflows from the Bear River were largely responsible for contaminating the reservoir ecosystem. Maximum concentrations of mercury in all three fish species, but especially bass, were high enough to warrant concern about toxic effects in fish and consumers of fish.     

Concentrations of microcystins in tissues of several fish species from freshwater reservoirs and ponds

The aim of this study is to summarise the determination of concentrations of microcystins (MCs) in muscle and liver of freshwater fish species caught in stagnant waters of the Czech Republic. Within the years 2007–2009, 351 muscle samples and 291 liver samples of 16 freshwater fish species derived from four fishponds, and four water reservoirs were analysed. MCs were detected in 53 liver samples. The highest concentrations of microcystins were determined in liver samples of carnivorous fish species; 50.3 ng/g of fresh weight (FW) in perch (Perca fluviatilis) and 22.7 ng/g FW in pikeperch (Sander lucioperca). MCs in liver were detected in other five fish species; asp (Aspius aspius), pike (Esox lucius), common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella) and European eel (Anguilla anguilla). Concentrations of MCs in liver of nine fish species (European bream, whitefish, tench, silver carp, European catfish, roach, chub, crucian carp and rudd) were below the detection limit of 1.2–5.4 ng/g FW for different MC congeners. However, the concentrations of MCs in all muscle samples were below the detection limit. The assessment of MCs concentrations might be influenced by the detection method used. Due to the concentrations of MCs being below the detection limit in muscle samples of all fish species analysed, it seems that there might be a low potential threat for human health in case of fish muscle consumption.     

Non-dioxin-like PCBs in ten different fish species from the Danube river in Serbia

This work has been developed to examine the level of non-dioxin-like (ndl) PCBs (28, 52, 101, 138, 153 and 180) in (a) ten different freshwater fish species from the Danube river, (b) two sampling points: up and downstream of the industrial zone of the city of Pancevo (ecological hot spot in Serbia) and (c) two time points i.e., in 2001 and 2006. Obtained results would serve to analyse spatial, temporal and congener profile characteristics of ndl PCBs cumulated in fish tissues due to environmental pollution. Sixty-four samples of the following species were collected: wels (Silirus glanus), pike (Esox lucius), bream (Abramis brama), crucian carp (Carassius carassius), pike pearch (Stizostedion lucioperca), barbel (Barbus barbus), tench (Tinca tinca), sterlet (Acipenser ruthenus L.), common carp (Cyprinus carpio) and bighead carp (Hypophthalmichthys nobilis). Gas chromatography coupled with electron capture detector was used for analysis of ndl PCBs. Total ndl PCBs content in upstream samples ranged from 2.7 to 98.1 ng/g and from 4.9 to 68.3 ng/g in 2001 and 2006, respectively. During the 5 years, ndl PCBs content increased significantly in downstream samples i.e., ndl PCBs varied from 13.7 to 46.1 ng/g and from 14.4 to 107.2 ng/g in 2001 and 2006, respectively. PCBs 138 and 180 were predominant congeners in 2001, while in 2006 the most abundant PCB congeners were 138 and 153. In 2006, the presence of PCB 28 and PCB 52 has indicated a recent contamination event. Data on continual monitoring of PCBs in all relevant environmental compartments together with appropriate biomonitoring data are expected to give comprehensive insight into the fate and behaviour profile of these contaminants.     

Metal concentrations and metallothionein levels in Mytilus galloprovincialis from Elefsis bay (Saronikos gulf, Greece)

Spatial and temporal variability of Cd, Cu, Cr, Ni, Zn, Fe and Mn and metallothionein (MT) concentrations were determined in mussels Mytilus galloprovincialis from Elefsis bay (Saronikos gulf, Greece). Higher concentrations of both metal concentrations and MTs were recorded in mussels inhabiting industrial locations (steelworks and shipyard), indicating a markedly higher metal bioavailability. However at these sites, located at the eastern part of the bay, mussel metal concentrations were not always correlated with both seawater metal concentrations and MTs possibly due to different time scales of integration of the metal sources into mussels and/or the participation of other metal regulatory mechanisms except MT induction. The pattern of the temporal variation of mussel metal concentrations and the MT levels was similar among stations with higher values during the winter–spring season and lower during the summer–autumn period. The inverse relationship of flesh condition index with mussel metal concentrations was attributed to the influence of mussel annual reproductive cycle.     

Persistent chlorinated pesticides in fish and cattle fat and their implications for human serum concentrations from the Sene-Gambian region

The concentrations of organochlorine pesticides (OCPs) in fish, shrimps, cattle fat and human serum samples from the Sene-Gambian region were measured using validated analytical methodologies. The results obtained were compared with those of other existing African studies and with data from other developing countries. In fish samples, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and HCB were detected with a frequency of 100%, whereas p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) was detected in eight, heptachlorepoxide in six and endosulfansulfate in five of the nine fish samples. Relatively low concentrations of OCPs were found in cattle and shrimp fat samples. p,p'-DDE and alpha-hexachlorocyclohexane (alpha-HCH) were the most frequently identified. The sum of HCHs ranged from undetected to 13.3 ng g-1 fat, the sum of DDTs from 11.1 to 199.2 ng g-1 fat and the sum of endosulfans from not detected to 49.7 ng g-1 fat in fish and shrimps. In serum samples, alpha-HCH, p,p'-DDE, o,p'-DDT and p,p'-DDT were detected in all 16 pooled serum samples, whereas endosulfansulfate, methoxychlor, mirex, heptachlorepoxide and endrin were detected in 15 samples with most of the concentrations below 10 ng mL-1. The concentrations of OCPs in human serum were given on a serum lipid and whole serum volume basis. The implications for the human diet of these OCP concentrations in serum were investigated by means of biomagnification factors related to the log Kow values of the targeted compounds. The current use of HCH mixtures was suggested to explain the unusually high alpha-HCH concentration. The distribution pattern of these OCPs in humans was also discussed and compared with that in other studies.     

Statistical distributions of trace metal concentrations in the northwestern Mediterranean atmospheric aerosol

The concentrations of 11 crustal and anthropogenic trace metals (Li, Al, V, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were measured from 2006 to 2008 in the atmospheric aerosol at a northwestern Mediterranean coast (station of Cap Ferrat, situated on the southeastern coast of France). Statistical models (lognormal, Weibull, and gamma) that best represented the trace metal distribution for this environment are described. The lognormal model was selected for the distributions of (in decreasing strength of the fit) Al, Co, Li, Zn, Mn, Cu, Pb, and Cd, i.e., metals that are introduced into the atmospheric aerosol by pulses inducing temporal variability in their concentrations. The gamma model was associated with Fe, i.e., metals that exhibit less inter-annual variability than the former trace metals. The third mode (Weibull) represented the distribution of the concentrations of V and Ni. The statistical approach presented in this study contributed to better define and constrain the distribution of the 11 trace metals of the atmospheric aerosol from the northwestern Mediterranean coast. In a close future, knowledge of these statistical distributions will allow using convolution models to separate their natural and anthropogenic contributions, therefore increasing our ability to study anthropogenic emissions of trace metals and their impact on the environment.     

Mercury concentration in the muscle of seven fish species from Chagan Lake,Northeast China

Chagan Lake is located downstream of the Second Songhua River basin in Northeast China. It is one of the top ten inland freshwater lakes, and an important aquatic farm in China. The lake has been receiving large amounts (currently at 1.5 × 10⁸ m³/a) of water from the river since 1984. This would pose a threat to the aquatic system of the lake because the river was seriously polluted with mercury in 1970s–1980s. The current study is the first to report the total mercury concentrations in fish found in the lake. Mercury concentrations in seven fish species collected from the lake in January 2009 were determined. The related human health risk from fish consumption was also assessed. The average concentration of mercury in the fish was 18.8 μg/kg of wet weight, ranging from 4.5 to 37.6 μg/kg of wet weight. A large difference in the mercury concentrations among the fish species was found. The mercury concentration was found to be higher in carnivorous species and lower in omnivorous and herbivorous species. This demonstrates greater mercury bioaccumulation in fish species at higher trophic levels. Mercury concentrations in fish showed significant positive correlations with age, length, and weight. No significant relationship was found between mercury concentrations in fish and the habitat preferences. Mercury concentrations in fish from the lake were within the limits of the international and national standards of China established for mercury. According to the reference doses established by the United States Environmental Protection Agency, the maximum safe consuming quantity considering all the fish was 297.3 g/day/person, which was more than five times as much as the current quantity (50 g/day/person) consumed by the local residents. This investigation indicates that the historical pollution of the Second Songhua River has not caused mercury bioaccumulation in fish muscle tissue of Chagan Lake. The present consumption of fish from the lake in the local area does not pose a threat to human health.     

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin

The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macroinvertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and wholebody fish. A selenium aquatic hazard assessment for the Basin was determined based on protocol established by Lemly. Throughout the Basin, water, macroinvertebrate, and whole fish samples exceeded levels suspected of causing reproductive impairment in fish. Population structures of several fish species implied that successful reproduction was occurring; however, the influence of immigration of fish from low-selenium habitats could not be discounted. Site-specific fish reproduction studies are needed to determine the true impact of selenium on fishery resources in the Basin. The U.S. Government’s right to retain a non-exclusive, royalty free license in and to any copyright is acknowledged.