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At least 541 records · Page 30Linked to original sources
USGS2000

Toxic responses of medaka, D-rR strain, to polychlorinatednaphthalene mixtures after embryonic exposure by in ovo nanoinjection: A partial life-cycle assessment

Polychlorinated naphthalenes (PCNs) are organic compounds with some chemical properties and uses similar to polychlorinated biphenyls. Polychlorinated naphthalenes have been detected in biota from certain aquatic environments. The toxicities of several PCN technical mixtures (Halowax) to medaka (Oryzias latipes) were determined by use of an embryo nanoinjection method. Medaka eggs (early gastrula) were injected with 0.5 nl of triolein (vehicle control) or 0.5 nl of four to five graded doses (0.3-30 ng/egg) of Halowax 1014, Halowax 1013, or Halowax 1051 in triolein. Following exposure, embryos developed, and fry were reared to sexual maturity (4 months), at which time they were euthanized. Responses were evaluated as early life stage (ELS) and early adult life stage (EALS) assessments. For ELS, lethality and sublethal alterations in embryos and larvae ( < 16 d old), such as craniofacial, cardiovascular, and myoskeletal deformities and abnormal or delayed hatch, were monitored for the first 9 d, and a dose severity index was computed. The EALS assessment examined the survival of 16-d-old larvae until early adulthood (123 ?? 3 d old), including gonadosomatic index (GSI) and morphometry. Halowax 1014 was found to be the most toxic mixture (LD50 4.2 ng/egg), whereas Halowax 1013 and 1051 were significantly less toxic (LD50s could not be determined). The gonadosomatic index of females was significantly less in fish dosed with Halowax 1014 or 1051. The LD50 for medaka embryos nanoinjected with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is about 0.75 pg/egg. Thus, Halowax 1014 was 5,585-fold less potent than TCDD. For Halowax 1014, ELS assessments accurately predicted the results of EALS assessments.

Environmental Toxicology and Chemistry↗
USGS2000

Effects of the mosquito larvicides temephos and methoprene on insect populations in experimental ponds

The nontarget effects of Abate® 4E (44.6% temephos) at 0.054 kg of active ingredient (a.i.) per 1 ha and of Altosid® Liquid Larvicide (5% methoprene) at 0.011 kg a.i./ha were investigated in 18 experimental ponds (average area, 202 m 2 ; maximum depth, 0.7 m) at Patuxent Wildlife Research Center, Laurel, Maryland, USA. Ponds were sprayed three times at 3-week intervals. Six ponds were sprayed with Abate, six with Altosid, and six with distilled water. Two insect-emergence traps per pond collected for 7 d and were then harvested 1 d before each spray and 13 to 14 days afterward. A repeated measures analysis of variance (ANOVA) revealed significant reductions in Shannon diversity, equitability, and numbers of individuals, species, and families in the Abate ponds relative to controls. Significant reductions also occurred in Ephemeroptera, Odonata, Diptera, Chironomidae, and Chaoborus sp. Hester-Dendy samplers were installed before spray one and harvested 16 d after spray three. Based on one-way ANOVA, Shannon diversity, equitability, and number of Ephemeroptera and Chironomidae were significantly reduced in the Abate ponds. Emergence data indicate only isolated cases with significant reductions in the Altosid ponds relative to controls, and the Hester-Dendy data indicate no significant differences between the Altosid and control ponds.

Maryland↗
USGS2000

Toxicity of Anacostia River, Washington, D.C., USA, sediment fed to mute swans (Cygnus olor)

Sediment ingestion is sometimes the principal route by which waterfowl are exposed to environmental contaminants, and at severely contaminated sites waterfowl have been killed by ingesting sediment. Mute swans ( Cygnus olor ) were fed a diet for 6 weeks with a high but environmentally realistic concentration (24%) of sediment from the moderately polluted Anacostia River in the District of Columbia, USA, to estimate the sediment's toxicity. Control swans were fed the same diet without the sediment. Five organochlorine compounds were detected in the treated diets, but none of 22 organochlorine compounds included in the analyses was detected in livers of the treated swans. The concentrations of 24 polynuclear aromatic hydrocarbons measured in the treated diet were as high as 0.80 mg/kg, and they were thought to have been responsible for the observed induction of hepatic microsomal monooxygenase activity in livers. A concentration of 85 mg/kg of lead in the diet was enough to decrease red blood cell ALAD activity but was not high enough to cause more serious effects of lead poisoning. The dietary concentrations of Al, Fe, V, and Ba were high compared to the concentrations of these elements known to be toxic in laboratory feeding studies. However, the lack of accumulation in the livers of the treated swans suggested that these elements were not readily available from the ingested sediment. We did not study all potential toxic effects, but, on the basis of those that we did consider, we concluded that the treated swans were basically healthy after a chronic exposure to the sediment.

District of Columbia↗
USGS2000

Quantifying solar spectral irradiance in aquatic habitats for the assessment of photoenhanced toxicity

The spectra and intensity of solar radiation (solar spectral irradiance [SSI]) was quantified in selected aquatic habitats in the vicinity of an oil field on the California coast. Solar spectral irradiance measurements consisted of spectral scans (280–700 nm) and radiometric measurements of ultraviolet (UV): UVB (280–320 nm) and UVA (320–400 nm). Solar spectral irradiance measurements were taken at the surface and at various depths in two marsh ponds, a shallow wetland, an estuary lagoon, and the intertidal area of a high-energy sandy beach. Daily fluctuation in SSI showed a general parabolic relationship with time; maximum structure–activity relationship (SAR) was observed at approximate solar noon. Solar spectral irradiance measurements taken at 10-cm depth at approximate solar noon in multiple aquatic habitats exhibited only a twofold variation in visible light and UVA and a 4.5-fold variation in UVB. Visible light ranged from 11,000 to 19,000 μW/cm 2 , UVA ranged from 460 to 1,100 μW/cm 2 , and UVB ranged from 8.4 to 38 μW/cm 2 . In each habitat, the attenuation of light intensity with increasing water depth was differentially affected over specific wavelengths of SSI. The study results allowed the development of environmentally realistic light regimes necessary for photoenhanced toxicity studies.

Environmental Toxicology and Chemistry↗
USGS2000

Assessment of the photoenhanced toxicity of a weathered oil to the tidewater silverside

Studies were conducted to determine the interactive toxicity of a water-accommodated fraction (WAF) of a weathered middle distillate petroleum and solar radiation to an estuarine organism, the tidewater silverside ( Menidia beryllina ). Juvenile silversides were monitored for survival and growth during a 7-d static renewal exposure to dilutions of WAFs of an environmentally weathered oil collected in the vicinity of an abandoned oil field in California. Ultraviolet (UV) treatments were based on incident sunlight intensity and spectra measured at this site. Exposure to UV alone was not lethal to the fish, and WAF in the absence of UV was toxic at the highest total petroleum hydrocarbon (TPH) concentration (3.03 mg/L) after 96 h of exposure. Water-accommodated fractions toxicity increased significantly with increasing UV irradiance and duration of exposure. The 7-d LC50 concentrations for the control, low, medium, and high irradiance were 2.84, 1.27, 0.93, and 0.51 mg/L TPH, respectively. Significant mortality occurred among fish previously exposed to WAF in the absence of irradiance, whereas WAF toxicity was unaffected by UV exposure prior to the toxicity test. Thus, the mode of action is a photosensitization of the accumulated petroleum residue rather than a photoactivation of WAF. Chemical analysis indicates that the WAF contains limited amounts of polycyclic aromatic hydrocarbons (PAHs) known to be photoenhanced, suggesting that other constituents may be responsible for the observed photoenhanced toxicity.

Environmental Toxicology and Chemistry↗
USGS2000

Seasonal concentrations of organic contaminants at the fall line of the Susquehanna River basin and estimated fluxes to northern Chesapeake Bay, USA

Riverine fluxes of several pesticides and other organic contaminants from above the fall line of the Susquehanna River basin to northern Chesapeake Bay, USA, were quantified in 1994. Base flow and storm flow samples collected at the fall line of the river from February to December 1994 were analyzed for both dissolved and particulate phase contaminants. Measured concentrations of the organonitrogen and organophosphorus pesticides varied mainly in response to the timing of their application to agricultural fields. Conversely, the concentrations of the more particle-sorptive contaminants such as polychlorinated biphenyls (PCBs), organochlorine (OC) insecticides, and polycyclic aromatic hydrocarbons (PAHs) were more directly correlated with river flow throughout the year. Annual fluxes were almost entirely in the dissolved phase for the organonitrogen and organophosphorus pesticides, distributed between the dissolved and particulate phases for the PCBs and OC insecticides, and primarily in the particulate phase for the PAHs.

Maryland, New Jersey, New York, Pennsylvania, Virg↗
USGS2000

Predicting the probability of detecting organochlorine pesticides and polychlorinated biphenyls in stream systems on the basis of land use in the Pacific Northwest, USA

We analyzed streambed sediment and fish tissue (Cottus sp.) at 30 sites in the Puget Sound and Willamette basins in Washington and Oregon, USA, respectively, for organochlorine pesticides and polychlorinated biphenyls (PCBs). The study was designed to determine the concentrations of organochlorine pesticides and PCBs in fish tissue and sediment by land use within these basins and to develop an empirical relation between land use and the probability of detecting these compounds in fish tissue or sediment. We identified 14 organochlorines in fish tissue and sediment; three compounds were unique to either fish tissue or sediment samples. The highest number of organochlorines detected in both fish tissue and streambed sediment was at those sites located in watersheds dominated by urban land uses. Using logistic regression, we found a significant relation between percentage agriculture and urban land use and organochlorines in fish tissue. The results of this study indicate that organochlorine pesticides and PCBs are still found in fish tissues and bed sediments in these two basins. In addition, we produced statistically significant models capable of predicting the probability of detecting specific organochlorines in fish on the basis of land use. Although the presented models are specific to the two study basins, the modeling approach could be applied to other basins as well.

Environmental Toxicology and Chemistry↗
USGS2000

Selected trace elements and organochlorines: some findings in blood and eggs of nesting common eiders ( Somateria mollissima ) from Finland

In 1997 and 1998, we collected blood samples from nesting adult female common eiders (Somateria mollissima) at five locations in the Baltic Sea near coastal Finland and analyzed them for lead, selenium, mercury, and arsenic. Eggs were collected from three locations in 1997 for analysis of selenium, mercury, arsenic, and 17 organochlorines (OCs). Mean blood lead concentrations varied by location and year and ranged from 0.02 ppm (residues in blood on wet weight basis) to 0.12 ppm, although one bird had 14.2 ppm lead in its blood. Lead residues in the blood of eiders were positively correlated with the stage of incubation, and lead inhibited the activity of the enzyme delta-aminolevulinic acid dehydratase (ALAD) in the blood. Selenium concentrations in eider blood varied by location, with means of 1.26 to 2.86 ppm. Median residues of selenium and mercury in eider eggs were 0.55 and 0.10 ppm (residues in eggs on fresh weight basis), respectively, and concentrations of both selenium and mercury in eggs were correlated with those in blood. Median concentrations of p,pa??-dichlorodiphenyldichloroethylene in eggs ranged from 13.1 to 29.6 ppb, but all other OCs were below detection limits. The residues of contaminants that we found in eggs were below concentrations generally considered to affect avian reproduction. The negative correlation of ALAD activity with blood lead concentrations is evidence of an adverse physiological effect of lead exposure in this population.

Coastal Areas↗
USGS2000

Evaluation of planar halogenated and polycyclic aromatic hydrocarbons in estuarine sediments using ethoxyresorufin-O-deethylase induction of H4IIE cells

Polycyclic aromatic hydrocarbons (PAHs) and planar halogenated hydrocarbons (PHHs), including polychlorinated dibenzo- p -dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were determined in fractionated sediment extracts from the Hudson-Raritan estuary and Newark Bay, New Jersey, USA, as part of a comprehensive risk assessment. Contributions of PCDDs/PCDFs, PCBs, and PAHs to the total toxic equivalents (TEQs) were measured using an H4IIE bioassay and calculated from instrumentally determined concentrations using international toxic equivalency factors. The H4IIE TEQs of whole and fractionated extracts were compared to calculated TEQs to investigate the applicability of the bioassay approach for evaluating 7-ethoxyresorufin- O -deethylease induction by PHHs and PAHs present together in complex mixtures. Although 2,3,7,8-tetrachloro-dibenzo- p -dioxin contributed from 41 to 79% of the calculated TEQs from PCDDs/PCDFs and planar PCBs in all sediments sampled, the PAH-containing fractions accounted for >80% of the total TEQs determined either instrumentally or by bioassay. Calculated TEQs from PAHs, based on reported toxic equivalency factors for only seven PAHs, were severalfold greater than the bioassay-derived TEQs of PAH-only fractions of the sediment extracts. Significant correlations were observed between bioassay and instrumentally determined toxic equivalents in the more purified fractions but not in fractions only purified by size-exclusion or argentate chromatographies alone.

Environmental Toxicology and Chemistry↗
USGS2000

Whole-lake burdens and spatial distribution of cadmium in sediments of Wisconsin seepage lakes, USA

Cadmium was quantified in the surface sediments of six seepage lakes ranging from 8 to 70 ha in surface area, 6 to 20 m in maximum depth, 5.2 to 7.0 in mean epilimnetic pH, and 1.7 to 6.8 mg·L −1 in dissolved organic carbon. Within each lake, dry-weight concentrations of cadmium (range, 0.02–7.17 μg·g −1 ) were positively correlated with volatile matter content of the sediments, which increased with water depth. Volumetric concentrations (i.e., mass per volume of wet sediment) were correlated with water depth in only one lake, and they more accurately represented the spatial distribution of sedimentary cadmium within the lakes. Analysis of sediment cores from two of the lakes indicated that surface sediments were enriched with cadmium. The source of cadmium and the within-lake processes controlling deposition to the sediments were presumably similar among the lakes, as demonstrated by the strong correlation between lake area and whole-lake burdens of cadmium in the surface sediments (range, 625–5785 g/lake). Hence, cadmium in these lakes appears to be derived largely from atmospheric deposition. When normalized for lake area, cadmium burdens in the surface sediments ranged from 62 to 92 g·ha −1 and were strongly correlated with dissolved organic carbon, but not with lake pH, which suggests a link between the transport of cadmium and organic matter to the sediments.

Wisconsin↗
USGS2000

Physiological measures of neurotoxicity of diazinon and malathion to larval rainbow trout ( Oncorhynchus mykiss ) and their correlation with behavioral measures

Relations between neurotoxicants and changes in physiological parameters and behavior were investigated in larval rainbow trout (RBT; Oncorhynchus mykiss ) exposed to sublethal concentrations of two organophosphate pesticides (OPs). Fish were exposed to diazinon and malathion in static-renewal experiments. After exposures for 24, 96, or 96 h, followed by 48 h of recovery, individual RBT were videotaped to assess locomotory behaviors. Brain tissue from the same fish was assayed for the physiological endpoints, cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number (B max ), and MChR affinity (K D ). Cholinesterase activity decreased significantly with increasing concentrations of both diazinon and malathion and differed significantly among exposure durations, with 24- and 96-h means less than 48-h recovery means. Decreases in B max with OP concentration were not significant for either chemical, and K D was unaffected. Changes in swimming speed and distance were significantly correlated with changes in ChE activity for both chemicals; rate of turning was significantly correlated with ChE activity in malathion exposures. These results suggest that correlations between physiological and behavioral changes previously seen in mammals also occur in fish.

Environmental Toxicology and Chemistry↗
USGS2000

Comparison of pesticides in eight U.S. urban streams

Little is known of the occurrence of pesticides in urban streams compared to streams draining agricultural areas. Water samples from eight urban streams from across the United States were analyzed for 75 pesticides and seven transformation products. For six of the eight urban streams, paired agricultural streams were used for comparisons. The herbicides detected most frequently in the urban streams were prometon, simazine, atrazine, tebuthiuron, and metolachlor, and the insecticides detected most frequently were diazinon, carbaryl, chlorpyrifos, and malathion. In contrast to similar-sized agricultural streams, total insecticide concentrations commonly exceeded total herbicide concentrations in these urban streams. In general, the temporal concentration patterns in the urban streams were consistent with the characteristics of the local growing season. The insecticides carbaryl and diazinon exceeded criteria for the protection of aquatic life in many of the urban streams in the spring and summer. When the country as a whole is considered, the estimated mass of herbicides contributed by urban areas to streams is dwarfed by the estimated contribution from agricultural areas, but for insecticides, contributions from urban and agricultural areas may be similar. The results of this study suggest that urban areas should not be overlooked when assessing sources and monitoring the occurrence of pesticides in surface waters.

Connecticut, Colorado, Florida, Georgia, Maryland,↗
USGS2000

Environmental contaminants in Texas, USA, wetland reptiles: Evaluation using blood samples

Four species of reptiles (diamondback water snake [ Nerodia rhombifer ], blotched water snake [ N. erythrogaster ], cottonmouth [ Agkistrodon piscivorus ], and red-eared slider [ Trachemys scripta ]) were collected at two contaminated and three reference sites in Texas, USA. Old River Slough has received intensive applications of agricultural chemicals since the 1950s. Municipal Lake received industrial arsenic wastes continuously from 1940 to 1993. Blood samples were analyzed for organochlorines, potentially toxic elements, genetic damage, and plasma cholinesterase (ChE). Dichlorodiphenyldichloroethylene (DDE) concentrations reached as high as 3.0 ppm (wet weight) in whole blood of a diamondback water snake at Old River Slough, a level probably roughly equivalent to the maximum concentration found in plasma of peregrine falcons ( Falco peregrinus ) in 1978 to 1979 when DDE peaked in this sensitive species. Possible impacts on diamondback water snakes are unknown, but at least one diamondback water snake was gravid when captured, indicating active reproduction. Arsenic was not found in red-eared sliders (only species sampled) from Municipal Lake. Red-eared sliders of both sexes at Old River Slough showed declining levels of ChE with increasing mass, suggesting a life-long decrease of ChE levels. Possible negative population consequences are unknown, but no evidence was found in body condition (mass relative to carapace length) that red-eared sliders at either contaminated site were harmed.

Texas↗
USGS2000

Biomarker response and health of polychlorinated biphenyl- and chlordane-contaminated paddlefish from the Ohio River Basin, USA

Fifty paddlefish ( Polyodon spathula ) collected from two sites on the Ohio River and from one site on the Cumberland River, USA, were examined to determine gonad polychlorinated biphenyl (PCB) and chlordane concentrations, amounts of plasma sex steroids (testosterone and estradiol), hepatic microsomal ethoxyresorufin- O -deethylase (EROD) activity, and the presence of immunoreactive cytochrome P450 1A (CYP1A) protein. Percent hatch and liver, spleen, and kidney histology were also determined. Gonad PCB and chlordane concentrations were significantly higher in Ohio River paddlefish than in Cumberland River paddlefish. Gonad PCB and chlordane concentration and gonad percent lipid were correlated in Ohio River paddlefish. Five of 10 Ohio River egg samples exceeded the Food and Drug Administration's action limit for chlordane (0.30 μg/g). Polychlorinated biphenyl congener-specific analysis detected predominantly the tetra-, penta-, and hexachlorobiphenyls in paddlefish testes. Plasma testosterone levels were significantly lower in males collected from the upper Ohio River site than those collected from the lower part of the river. There was no measurable hepatic microsomal EROD activity in any of the 50 paddlefish collected from the three sites. Western blotting analysis confirmed that a rabbit antitrout CYP1A1 IgG antibody did not recognize a CYP1A protein in paddlefish liver microsomes. Percent hatch was not significantly different in eggs collected from the Cumberland (88–96%) and Ohio Rivers (90–95%). Histological analysis of liver, spleen, and kidney detected the presence of hepatic steatosis and hemosiderosis, splenic lymphoid cell depletion, and hyperplasia of interrenal and chromaffin tissues. Immunosuppression, hepatic metabolic disorders, and altered neuroendocrine function may be occurring in Ohio River paddlefish. Results presented here suggest that organochlorine exposure may be jeopardizing the long-term health of Ohio River paddlefish and that additional investigation of contaminant effects on immune system function and hormone levels in paddlefish is warranted.

Alabama, Georgia, Illinois, Indiana, Kentucky, Mar↗
USGS2000

Effects of white phosphorus on mallard reproduction

Extensive waterfowl mortality involving thousands of ducks, geese, and swans has occurred annually at Eagle River Flats, Alaska since at least 1982. The primary agent for this mortality has been identified as white phosphorus. Although acute and subacute lethality have been described, sublethal effects are less well known. This study reports on the effects of white phosphorus on reproductive function in the mallard ( Anas platyrhynchos ) in captivity. Fertility, hatching success, teratogenicity, and egg laying frequency were examined in 70 adult female mallards who received up to 7 daily doses of 0, 0.5, 1.0, and 2.0 mg/kg of white phosphorus. Measurements of fertility and hatchability were reduced by the white phosphorus. Teratogenic effects were observed in embryos from hens dosed at all treatment levels. Egg laying frequency was reduced even at the lowest treatment level; treated hens required a greater number of days to lay a clutch of 12 eggs than control hens. After two doses at 2.0 mg/kg, all females stopped laying completely for a minimum of 10 days and laying frequency was depressed for at least 45 days. Fertility of 10 adult male mallards dosed with 1.0 mg/kg of white phosphorus did not differ from 10 controls, but plasma testosterone levels were significantly (p < 0.05) reduced in the treated males 1 day after dosing ended. These results provide evidence that productivity of free-ranging mallards may be impaired if they are exposed to white phosphorus at typical field levels.

Alaska↗
USGS2000

Effects of dietary polychlorinated biphenyl exposure on energetics of white-footed mouse, Peromyscus leucopus

Energy budgets have provided physiological ecologists with a vital link between environmental variables and individual performance and should also prove useful to ecotoxicologists in understanding the effects of sublethal exposure in the field. Exposure to toxic compounds is likely to be metabolically expensive and may result in a trade-off between energy spent to detoxify and excrete contaminants and energy allocated to growth or reproduction. To quantify the energetic cost of polychlorinated biphenyl (PCB) exposure, we fed captive white-footed mice ( Peromyscus leucopus ) diets containing PCBs (2:1 Aroclor® 1242:1254) at levels of 0, 0.1, 10, and 25 ppm (mg PCBs/kg food). After six weeks on the diets, there were no differences in food intake (g/d), diet digestibility (%), or body mass related to the level of dietary PCBs. This indicated that short-term exposure to PCBs did not cause a detectable increase in energy need as measured by voluntary food intake. We continued to feed mice the PCB-containing diets for one year, at which time we repeated the food intake trial, and also measured oxygen consumption at 20 and 30°C. After one year, all mice had gained mass, but mice on the 25-ppm diet tended to be heavier than mice in the other groups. Compared to the control group, mice on the 25-ppm diet had higher food intake (4.1 vs 3.7 g/d; p = 0.06) and higher oxygen consumption at 30°C (40.1 vs 36.6 ml O 2 /h; p = 0.01). These results suggest that there is an energetic cost to long-term contaminant exposure that, when combined with other environmental stresses, may influence patterns of energy acquisition and allocation.

Environmental Toxicology and Chemistry↗
USGS2000

Organochlorine and trace element contamination in wintering and migrating diving ducks in the southern Great Lakes, USA, since the zebra mussel invasion

Because of the potential for increased trophic transfer of contaminants by zebra mussels ( Dreissena sp. ) to higher trophic levels, we collected four species of waterfowl (n = 65 ducks) from four locations in Lake Erie, Lake St. Clair, and Lake Michigan, USA, between 1991 and 1993 for organochlorine contaminant and trace element analyses. Geometric mean concentrations of total polychlorinated biphenyls (PCBs) and p , p ′-dichlorodiphenyldichloroethylene (DDE) were 1.35 and 0.15 μg/g wet weight in lesser scaup ( Aythya affinis ) carcasses and were below known effect levels. Total PCBs in 80% of carcasses, however, were above the U.S. Food and Drug Administration's threshold of 3.0 μg/g lipid weight for consumption of poultry. With the exception of selenium, trace elements were also at background or no-effect levels. Selenium concentrations in livers of 95% of lesser scaup, 90% of bufflehead ( Bucephala albeola ), and 72% of common goldeneye ( Bucephala clangula ) were in the elevated (>10 μg/g dry wt) or potentially harmful range (>33 μg/g dry wt). The effects of these high selenium concentrations are unknown but should be investigated further based on reproductive effects observed in field and laboratory studies of dabbling ducks and because lesser scaup populations are declining. Concentrations of total PCBs in dreissenid mussels in western Lake Erie were 10 times higher than in the upper Mississippi River but were similar to concentrations in other industrialized rivers in Europe and the United States. Metal concentrations were similar to other industrialized sites where zebra mussels have been sampled.

Indiana, Michigan, Ohio↗