bluuebunny/crossref_metadata_2025 huggingface dataset:
Copper toxicity to the endoparasitic trematode (Posthodiplostomum minimum) relative to physid snail and bluegill sunfish intermediate hosts
Authors: Soucek David J , Noblet Gayle P
Published: March 2010

A laboratory study was conducted to determine copper toxicity to the endoparasitict ematode Posthodiplostomum minimum (MacCallum) relative to snail first intermediate hosts and bluegills (Lepomis macrochirus Rafinesque) as second intermediate hosts. To determine copper effects on cercariae, the life-cycle stages of P. minimum were established in the laboratory. A 96-h median lethal concentration (LC50) test for bluegills was performed, and the calculated value of 0.892 mg/L total Cu was considered in selection of copper concentrations for all other experiments. Snail hosts (Physella gyrina (Say)) exposed to copper concentrations equal to 0, 8.9, 22.3, 44.6, and 89.2 μg/L Cu, exhibited a significant toxic response with ∼64% and ∼87% mortality occurring in the 44.6 and 89.2 μg/L concentrations, respectively. The 7-d LC50 for snails was 38.0 μg/L Cu. Free-swimming cercariae exposed to the same copper concentrations exhibited a similar toxic response with a 9-h LC50 of 32.0 μg/L Cu and a 12-h LC50 of 26.0 μg/L Cu.
Seasonal variations in susceptibility of Apis mellifera to the synergistic action of prochloraz and deltamethrin
Authors: Meled Maggy , Thrasyvoulou Andreas , Belzunces Luc P
Published: March 2010

The synergistic action of prochloraz and deltamethrin was investigated in summerand winter bees. Prochloraz and deltamethrin were used at sublethal doses that did not induce any significant mortality. Bees were treated with different doses of deltamethrin, either alone or in combination with prochloraz, at the constant field rate of 25 g/ha. In summer bees, the combination of prochloraz and deltamethrin at 125 mg/ha triggered a synergy that produced approx. 63 ± 5% mortality (corrected) after 24 h. At 62.5 mg/ha, deltamethrin still acted in synergy with prochloraz by inducing about 32.5 ± 3.5% mortality (corrected) after 24 h. The field rate of 31.25 mg/ha was the lowest dose at which deltamethrin acted in synergy with prochloraz in summer bees. In winter bees, no synergy occurred between prochloraz and deltamethrin at doses of 125 and 250 mg/ha. The deltamethrin dose had to be increased to 500 mg/ha to observe a synergy that produced only 47 ± 11.7% mortality (corrected) after 24 h. Considering the deltamethrin doses at which synergy occurred, summer bees appeared to be approximately eightfold more susceptible than winter bees to the synergistic action of prochloraz and deltamethrin.
Blood changes in mallards exposed to white phosphorus
Authors: Sparling Donald W , Vann Stephanie , Grove Robert A
Published: March 2010

White phosphorus (P4) has been extensively used by the military for various purposes, including marking artillery impacts and as an obscurant. Target practice in an Alaskan tidal marsh during the last 4 decades has deposited large amounts of P4 particles in sediments and water, which have resulted in die-offs of several waterfowl species. Because the toxicity of P4 in birds has not been well documented and because it is quickly excreted or metabolized in living animals, we sought to determine the effects of experimental dosing on blood characteristics in game farm mallards (Anas platyrhynchos). In two experiments, one employing single doses of 5.4 mg P4 per kilogram body weight in corn oil and the other using daily repeated doses of pelletized P4 at either 0.5 or 1.0 mg/kg, there were significant changes in aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase (LDH), inorganic P, hematocrit, and hemoglobin. Other indications of exposure included changes in uric acid, creatinine, and total protein, which were consistent with reported liver and kidney damage due to this contaminant. Changes in white blood cells included a greater frequency of thrombocytes and fewer lymphocytes in dosed birds compared to controls. A biomarker of exposure based on LDH activity and hemoglobin is proposed.
Photoenhanced toxicity of a carbamate insecticide to early life stage anuran amphibians
Authors: Zaga Angela , Little Edward E , Rabeni Charles F , Ellersieck Mark R
Published: March 2010

Aican clawed frog (Xenopus laevis) and gray tree frog (Hyla versicolor) embryos and tadpoles were exposed to sublethal levels of carbaryl, a broad-spectrum insecticide, and ultraviolet radiation to determine interactive and sublethal effects. Ultraviolet intensity (UV-B [285–320 nm] plus UV-A [321–400 nm]) was controlled with various types of plastic filters and quantified with a scanning spectroradiometer. Significant differences in swimming activity and mortality of both species were evident during the 96-h experiments. Ultraviolet-B radiation alone and carbaryl in the presence of UV-B significantly decreased swimming activity of both species. As little as 1.5% intensity of ambient solar UV-B radiation photoactivated carbaryl. Toxicity of 7.5 mg/L carbaryl increased by 10-fold in the presence of UV-B in all species and life stages tested. Our results indicate that photoenhancement by solar UV-B radiation should be considered when evaluating the toxicity of contaminants to amphibians and other organisms.
Predicting toxicity of sediments spiked with silver
Authors: Berry Walter J , Cantwell Mark G , Edwards Philip A , Serbst Jonathan R , Hansen David J
Published: March 2010

Previous experiments conducted with feshwater sediments spiked with silver have shown that, when expressed on a dry weight basis, the toxicity of silver is sediment-specific and dependent on the form of silver added (e.g., AgNO3, Ag2S). This study was conducted to assess the usefulness of silver interstitial water toxic units (IWTU) and acid volatile sulfide (AVS) concentrations in predicting the biological effects of silver species across sediments, regardless of the species of silver present. Two saltwater sediments were spiked with a series of concentrations of silver. The amphipod, Ampelisca abdita, was then exposed to the sediments in ten-day toxicity tests. Amphipod mortality was sediment-specific when expressed on a dry weight basis, but not when based on IWTU or simultaneously extracted metal (SEM)-AVS. Sediments with an excess of AVS relative to SEM had IWTU <0.5, and were generally not toxic. Sediments with an excess of SEM relative to AVS had silver IWTU >0.5, but no measurable AVS, and were generally toxic. Sediments with measurable AVS were not toxic. Reanalysis of the previously published data from the freshwater sediments spiked with silver showed mortality to be correlated with nominal SEM-AVS and with silver IWTU. Taken together, these results support the use of AVS and silver IWTUs in predicting the toxicity of silver in sediments.
Effects of chloride, calcium, and dissolved organic carbon on silver toxicity: Comparison between rainbow trout and fathead minnows
Authors: Bury Nicolas R , Galvez Fernando , Wood Chris M
Published: March 2010

The effects of independently altering chloride, calcium, and dissolved organic carbon (DOC) on the toxicity of silver (presented as AgNO3) were compared between rainbow trout (Oncorhynchus mykiss) and fathead minnows (Pimephales promelas). The 96-h median lethal concentration (LC50) toxicity tests for both species were performed under the same conditions, within the same containers. In addition, the effect of altering [Cl−] on silver-induced perturbations to body Na+ influx and gill silver load was studied. Toxicity tests were conducted in synthetic soft water (50 μM Na+, 50 μM Cl−, 50 μM Ca2+, 0.3 mg DOC/L). The [Cl−], [Ca2+], and [DOC] were adjusted by the addition of NaCl, CaNO3, or humic acid, respectively. On the basis of total silver, increasing [Cl−] over a range of 50 μM to 1,500 μM resulted in a 4.3-fold increase in the 96-h LC50 values (decrease in toxicity) for rainbow trout, but did not significantly affect the 96-h LC50 values for fathead minnows. Increasing water [Ca2+] (from 50 to 2,000 μM) had only a small influence (1.5-fold increase) on the 96-h LC50 values in either species. However, increasing DOC levels (from 0.3 to 5.8 mg DOC/L) significantly increased the 96-h LC50 values (2.7- to 4.1-fold increases) in both species. If the 96-h LC50 values are calculated on the basis of ionic silver, Ag+ (utilizing the aquatic geochemical computer program MINEQL+ ), then, in the case of rainbow trout, toxicity correlates to Ag+. However, this correlation does not exist for fathead minnows. Increasing [Cl− did not affect the degree of perturbation of Na+ influx during acute exposure (first 4 h) to 8 μg Ag/L in either species, nor did it affect the whole-body silver uptake rates, but it did reduce the gill silver load. These results demonstrate that differences exist in the way in which water chemistry ameliorates silver toxicity between rainbow trout and fathead minnows.
Influence of water quality on silver toxicity to rainbow trout (Oncorhynchus mykiss), fathead minnows (Pimephales promelas), and water fleas (Daphnia magna)
Authors: Karen Daniel J , Ownby David R , Forsythe Barry L , Bills Todd P , La Point Thomas W , Cobb George B , Klaine Stephen J
Published: March 2010

Toxicity bioassays were conducted to quantify water quality conditions under which silver, as silver nitrate, is toxic to Oncorhynchus mykiss, Pimephales promelas, and Daphnia magna. Bioassays for P. promelas and D. magna were conducted as static replacement tests, whereas a flow-through bioassay system was modified and used for O. mykiss. Results from 96-h toxicity bioassays for O. mykiss indicated that chloride, hardness, and dissolved organic carbon (DOC) protected against silver toxicosis, with DOC affording the highest protective effects. For P. promelas and D. magna, little protection was provided by increased CaCO3 alone, whereas DOC had a major ameliorating influence on measured silver toxicity. Lower concentrations of chloride (<20 mg/L) had little effect on reducing silver nitrate toxicity. Dissolved organic carbon was more important than hardness for predicting the toxicity of ionic silver in natural waters to O. mykiss, P. promelas, and D. magna. Similarly, DOC significantly reduced silver nitrate toxicity to trout, whereas Cl− and hardness had only a minor protective effect. However, Cl−/DOC mixtures showed a greater-than-additive protective effect. Thus, we suggest that incorporating an organic carbon coefficient into the silver criterion equation will enhance the criterion values for site specificity.
Physiological effects of dietary silver sulfide exposure in rainbow trout
Authors: Galvez Fernando , Wood Chris M
Published: March 2010

Silver accumulation was examined in juvenile rainbow trout during a 58-d feeding study with silver sulfide (Ag2S) added to the diet at concentrations ranging from 0 to 3,000 mg/kg Ag. Silver in the livers of fish fed the 3,000-mg/kg diet reached a level approximately fourfold higher than the control, representing an initial accumulation rate of 9.5 ng/(g·d). Despite this increase in silver levels in the liver, no influence of liver copper levels was observed. In comparison, there were no significant elevations in silver burdens in the kidneys, gills, or intestines, apart from a transient increase in the gills of fish fed the 3,000-mg/kg Ag diet on day 24 only. Daily food consumption rates were lowered by 14 to 22% in all the Ag2S treatments relative to control levels, possibly because of the decreased palatability of the Ag-laden diets. However, there were no significant differences in growth rates between any of the treatments for the duration of the study, suggesting a lack of any physiological perturbation by dietary Ag2S exposure. The results of this study suggest that dietary silver sulfide exposure at or below 3,000 mg/kg Ag is physiologically benign over a 58-d period.
Using statistical power to optimize sensitivity of analysis of variance designs for microcosms and mesocosms
Authors: Kennedy James H , Ammann Larry P , Waller William T , Warren James E , Hosmer Alan J , Cairns Stefan H , Johnson Philip C , Graney Robert L
Published: March 2010

Controlled laboratory and field studies are often used in the risk assessment process to evaluate the fate and effects of chemicals on the structure and function of populations and communities. These studies have evolved, over the past 20+ years, from field studies to outdoor simulated ecosystems (microcosms and mesocosms). A review of pertinent literature indicates that analysis of variance is most often used to evaluate those data. Assumptions of homogeneity of variance are often violated, however, and standard normal-theory methods should not be used. Counts of macroinvertebrates collected from a mesocosm and microcosm study were analyzed using log-linear regression models (general and robust) written in the S-Plus statistical language. The statistical power of the analysis is also provided. Dose-response experiments may result in elimination of sensitive taxa for all replicates of a given condition. The program proposes a new method to deal with these zero counts. This program and directions for its use are available from an anonymous file transfer protocol (FTP) site.
Nonmetric multivariate analysis in community-level ecotoxicology
Authors: Clarke K Robert
Published: March 2010

Community-level data, typically in the form of abundances of over 100 species, are widely collected in the context of environmental monitoring, e.g., of the effects of disposal of drilling muds in offshore oil operations. The statistical properties of the resulting abundance arrays preclude the use of “classical” multivariate analyses, such as principal components and multivariate analysis of variance. One alternative is the use of nonparametric displays and tests, such as nonmetric multidimensional scaling (MDS) and variations of Mantel tests on similarity matrices. These do not require the restrictive assumptions of parametric techniques and possess a conceptual simplicity, facilitating their use and understanding by environmental managers and regulators. A monitoring example is discussed from Norwegian oil fields, for which such analyses have had a significant impact on environmental practice. The techniques are equally applicable to assessing outcomes from community-level laboratory experiments and bioassays. The paper exemplifies the analysis approach taken at the Plymouth Marine Laboratory (and encapsulated in the PRIMER software) through (1) observational studies of pollution gradients in North Sea sediments and heavy metal pollutants in the Fal estuary, UK; (2) an experimental study on differential effects of metals on marine nematode communities; and (3) a bioassay approach employing a microcosm experiment on Fal estuary sediments.
Enhancing the bioavailability of organic compounds sequestered in soil and aquifer solids
Authors: White Jason C , Alexander Martin , Pignatello Joseph J
Published: March 2010

A study was conducted to find ways to increase the biodegradability of compounds that have aged in soil or aquifer material and become less bioavailable. Slurrying enhanced the rate and extent of biodegradation by individual bacterial strains of aged and unaged phenanthrene and di(2-ethylhexyl) phthalate in soils and aquifer solids. After bacterial degradation of aged phenanthrene in unslurried soil had largely ceased, the residual compound was metabolized if the soil was slurried and reinoculated with a phenanthrene-degrading bacterium. The rate and extent of biodegradation of aged phenanthrene by Pseudomonas sp. were enhanced when anthracene or pyrene was added to the soil at the same time as the bacterium, although the organism could not metabolize anthracene or pyrene. Moreover, anthracene or pyrene increased the amount of aged phenanthrene removed from soil by a mild extractant. The data show that the bioavailability of organic compounds that become sequestered by aging can be altered by appropriate soil treatments.
Potential use of cholinesterase in monitoring low levels of organophosphates in small streams: Natural variability in three-spined stickleback (Gasterosteus aculeatus) and relation to pollution
Authors: Sturm Armin , Wogram Jöorn , Hansen Peter-Diedrich , Liess Mathias
Published: March 2010

The potential use of cholinesterase(ChE) in body muscle of three-spined stickleback (Gasterosteus aculeatus) as a biomarker of organophosphate (OP) contamination was investigated. Fish were sampled from nine headwater streams directly after the main application period (July 1995) and 2 months after the end of OP use (October 1995). Cholinesterase activity was inversely related to fish weight. Muscle ChE was comprised of both acetylcholinesterase and pseudocholinesterase. In July, fish from two sites (A and B) had significantly lower (∼30%) ChE activities than fish from all but one of the other sites. In October, the range of ChE activities was similar to that observed in July; however, no site significantly differed from the majority of other sites. The OP parathion was detected in suspended particulates at sites A and B. This suggests that decreased ChE in July reflects OP exposure. Because sampling of suspended particulates at site A occurred with a higher resolution than at the other sites and because decreases were close to the natural variability, however, this relationship cannot be demonstrated with certainty. The reported characteristics of ChE and its natural variability in stickleback represent baseline data for its use in the monitoring of OP contamination of small streams.
Use of nonpolar resin for reduction of fluoranthene bioavailability in sediment
Authors: Kosian Patricia A , West Corlis W , Pasha Mumtaz S , Cox Julie S , Mount David R , Huggett Robert J , Ankley Gerald T
Published: March 2010

The objective of our study was to evaluate the effectiveness of Amersorbb® 1500, a carbonaceous resin, for reducing the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sediment. Initial studies were conducted with a model PAH, fluoranthene, to determine how effective the resin would be at reducing fluoranthene concentrations in water and sediment pore water. Fluoranthene concentrations were reduced by more than 70% within 24 h when 0.1 g of unconditioned resin was added to 500-ml solutions containing 160 μg/L fluoranthene. Within 48 h, concentrations decreased by more than 92%. Addition of Ambersorb to fluoranthene-spiked sediment showed similar reductions of fluoranthene concentrations in pore water. Based on these initial results, a 10-d bioaccumulation/toxicity experiment was conducted in which the oligochaete Lumbriculus variegatus was exposed to fluoranthene-spiked sediment with and without resin. Chemical analyses showed that sediment amended with resin had greatly diminished pore-water fluoranthene concentrations compared with sediment without resin. Proportional reductions in whole-body fluoranthene concentrations were observed in oligochaetes exposed to resin-amended sediments. As would be expected from enhancement of fluoranthene toxicity by ultraviolet light, organisms exposed to fluoranthene-spiked sediment exhibited significant mortality upon subsequent exposure to ultraviolet light. Consistent with their lower body burdens, organisms from resin-treated sediment lacked this sensitivity (100% survival). These experiments demonstrate that Ambersorb 1500 effectively reduces the bioavailability of fluoranthene in spiked sediment. Additional studies are needed to define the boundaries of the resin's effectiveness in influencing the bioavailability of other PAHs and nonpolar organic chemicals in spiked and field-contaminated sediments.
Accumulation of copper, chromium, and arsenic in blue mussels (Mytilus edulis) from laboratory and field exposures to wood treated with chromated copper arsenate type C
Authors: Adler-Ivanbrook Leslie , Breslin Vincent T
Published: March 2010

Laboratory and field experiments were conducted to examine the uptake of Cu, Cr, and As leached from southern yellow pine (SYP) treated with chromated copper arsenate type C (CCA-C), as well as effects on mortality and growth, in blue mussels (Mytilus edulis). Mussels were exposed to CCA-C-treated wood at a preservative retention of 40 kg/m3 and control (nontreated) SYP in laboratory flow-through sea table and field exposure experiments for 9 months in 1994 and 3 months in 1995. Mussels were sampled at regular intervals to evaluate possible short- and long-term exposure effects. Individual mussels were measured to determine the length, dry weight, and condition index. Mussel tissues were then analyzed for Cu, Cr, and As. Results showed few significant differences in condition index, dry weight, and length between CCA-C-exposed and control mussels. In addition, no statistically significant differences in mortality were found between the mussels exposed to CCA-C-treated and nontreated SYP in the laboratory flow-through sea table and field exposure experiments. Significant differences in Cu, As, and Cr contents in mussel tissues between treatments were few, and generally cannot be attributed to exposure to CCA-C-treated SYP. The lack of Cu, Cr, and As uptake from CCA-C-treated SYP was attributed to the low, although continuous, rate of release of these elements from CCA-C-treated wood and to the experimental design, which allowed continuous flushing, prohibiting the accumulation of these elements in the water surrounding the mussels.
Sediment organic matter content as a confounding factor in toxicity tests with Chironomus tentans
Authors: Lacey Rebekah , Watzin Mary C , McIntosh Alan W
Published: March 2010

Physicochemical characteristics of sediment unrelated to contaminant levels and bioavailability may influence the outcome of toxicity tests. In particular, sediment organic matter content has the potential to be a confounding factor in toxicity tests using the midge larva Chironomus tentans because the larvae are infaunal and feed on organic matter in the sediments. To examine this possibility, we conducted a series of tests using formulated sediments with varying organic matter contents (0–20%) following the standard U.S. Environmental Protection Agency (U.S. EPA) 10-day C. tentans growth and survival protocol. Formulated sediments made with peat moss, α-cellulose, and maple leaves were tested. An organic-rich natural sediment diluted with formulated sediment to achieve a range of organic matter contents was also examined. In a final experiment, sediments containing each of the four organic matter sources at the same concentration were tested against one another. Survival was not greatly affected by concentration of organic matter, except at the lowest concentrations in natural sediment (6–7%), where survival dipped below 70%. In experiments using peat moss, α-cellulose, and maple leaves, significant differences in C. tentans growth (measured as ash-free dry weight) were found at different organic matter concentrations. In contrast, concentration of organic matter in the natural sediment dilution series had little effect on growth, perhaps because much of this material was highly refractory. In the comparison experiment, growth differed significantly among the four sediments, with best growth achieved with α-cellulose and leaves. These results suggest that both organic matter quantity and quality can be confounding factors in toxicity tests using C. tentans.
Secondary poisoning in the common shrew (Sorex araneus) fed earthworms exposed to an organophosphate pesticide
Authors: Dell'Omo Giacomo , Turk Anthony , Shore Richard F
Published: March 2010

Earthworms Esinia spp. were kept for a 48-h period in artificial soil contaminated with a sublethal dose of dimethoate, an organophosphate pesticide. Different groups of common shrews, Sorex araneus, were fed earthworms that had been exposed to contaminated soil either 1, 5, or 10 d previously. Cholinesterase (ChE) activity was measured in worms and in the shrews before and after they were fed contaminated worms. After exposure to dimethoate-treated soil, ChE activity in worms was inhibited by 90%. Recovery was slow, and ChE activity was still markedly inhibited (35% of the control level) 40 d after exposure. Whole blood ChE activity in shrews was significantly depressed (64% of preexposure levels) when animals were fed worms that had been exposed to dimethoate-treated soil on the previous day. There was no such significant inhibition in shrews fed worms that had been exposed to contaminated soil either 5 or 10 d previously.
Incidence of lethal bird poisoning reduced by regurgitation of pesticide-treated food
Authors: Pascual Juan A , Hart Andrew D M , Fryday Steve L
Published: March 2010

Regurgitation by birds feeding on pesticide-treated seed was quantified in two experiments, and its role in reducing the risk of acute poisoning from an organophosphorus pesticide was assessed. Captive feral pigeons (Columba livia) were offered fonofos-treated seed ad libitum on a test day after a 6-d period in which one group was given free access to untreated seed and another group was given no food in one experiment or 15% of normal intake in the other. Avoidance of treated seed reduced intake substantially, preventing the ingestion of lethal doses for all birds fed ad libitum and some but not all of the food-restricted birds. Some of the latter regurgitated most of the seed taken in (>60%), reducing by ∼50% the dose of pesticide assimilated and lowering the dose from above to below lethal levels. Regurgitation was the most likely explanation for the survival of at least 12 and 50% of the food-restricted birds in these experiments. Regurgitation reduced but did not prevent mortality, because some birds died without regurgitating and others despite doing so. This study provides the first clear evidence that regurgitation can directly reduce mortality of birds exposed to pesticides in their food. Implications for the risk of poisoning wild birds and avian toxicity testing are discussed.
Chronic and reproductive toxicity of a mixture of 15 methylsulfonyl-polychlorinated biphenyls and 3-methylsulfonyl-2,2-bis-(4-chlorophenyl)-1,1-dichloroethene in mink(Mustela vison)
Authors: Lund Bert-Ove , Örberg Jan , Bergman Åke , Larsson Christina , Bergman Anders , Bäcklin Britt-Marie , Håkansson Helen , Madej Andrzej , Brouwer Abraham , Brunström Björn
Published: March 2010

A synthetic mixture of 16 aryl methyl sulfones was given in the feed to female mink for one year (three times a week, resulting in a mean daily exposure of 0.1 mg/mink). The mink were mated after 9 months of exposure and the reproductive outcome was studied. The dams and kits were examined for biochemical and toxic effects. The litter size was significantly increased (50%) in the exposed group, and the mean birth weight was 20% lower than that of the controls. Kit survival was 47% by 2 weeks after birth in the exposed group, as compared to 73% in the control group. Both adults and kits had induced (5- to 11-fold) hepatic activities of pentoxyresorufin-O-dealkylase. In livers from the dams, catabolism of progesterone in vitro was increased almost twofold. Decreased thyroid hormone concentrations (total triiodothyronine and total thyroxine, 30–35% of control values) in plasma were observed in the adults. The bioaccumulation factor for the mixture of 3- and 4-methylsulfonyl-polychlorinated biphenyls (PCBs) was 2.1 (muscle vs feed concentration). The 3-methylsulfonyl-PCBs accumulated 2- to 65-fold in liver relative to muscle and lung. At the cessation of the exposure period, the total concentrations of aryl methyl sulfones in the dams and their 5-week-old kits were 18 ± 2 and 21 ± 3 μg/g, respectively (lipid weight, muscle), demonstrating significant transport from dams to kits and accumulation in the kits.
Behavioral avoidance: Possible mechanism for explaining abundanc and distribution of trout species in a metal-impacted river
Authors: Hansen James A , Woodward Daniel F , Little Edward E , DeLonay Aaron J , Bergman Harold L
Published: March 2010

Behavioral avoidance of metal mixtures by rainbow trout (Oncorhynchus mykiss) was determined in the laboratory under water quality conditions that simulated the upper Clark Fork River, Montana, USA. A metal mixture with a fixed ratio of observed ambient metal concentrations (12 μg/L Cu:1.1 μg/L Cd:3.2 μg/L Pb:50 μg/L Zn) was used to determine avoidance in a countercurrent avoidance chamber. Rainbow trout avoided all metal concentrations tested from 10 to 1,000% of the simulated ambient metal mixture. The behavioral response of rainbow trout to the metal mixture was more sensitive than the response of brown trout (Salmo trutta) previously reported from the same laboratory under the same experimental conditions. Additionally, rainbow trout that were acclimated to the simulated ambient metal mixture for 45 d preferred clean water and avoided higher metal concentrations. Therefore, our laboratory experiments on the behavioral avoidance responses of rainbow trout, as well as previously reported experiments on brown trout, show that both species will avoid typical metal concentrations observed on the Clark Fork River. And the greater sensitivity of rainbow trout to the metal mixture may explain, in part, why rainbow trout populations appear to be more severely affected, compared to brown trout populations, in the upper Clark Fork River.
An in vivo testing system for endocrine disruptors in fish early life stages using induction of vitellogenin
Authors: Tyler Charles R , van Aerle Ronny , Hutchinson Tom H , Maddix Sue , Trip Heleanne
Published: March 2010

An enzyme-linked immunosorbent assay (ELISA) based oncarp (Cyprinus carpio) vitellogenin (c-VTG, an estrogen-dependent precursor of egg yolk) was developed to quantify VTG in the fathead minnow (Pimephales promelas) and was employed to establish an in vivo testing system for estrogens in fish early life stages. The working range of the c-VTG ELISA was between 1 and 50 ng/ml (20%–80% binding). The inter- and intraassay variations were 9.7 ± 3% and 8.9 ± 3.4% (n = 15), respectively. Plasma and whole body homogenates from females and from estrogenized male fathead minnow diluted parallel with the c-VTG standard. Measurements of plasma VTG fractionated on sodium dodecyl sulphate gels and quantified using densitometry were compared with measurements with the same plasma samples using the c-VTG ELISA and they were similar for the carp and fathead minnow. The plasma concentration of VTG in the male fathead minnow was 25 ± 6 ng/ml, whereas in females, plasma concentrations of VTG ranged from 5.3 ± 1 μg/ml to 182 ± 7.6 μg/ml, depending on the state of maturity. Exposure of fathead minnows to estradiol-17β in the water (nominal concentrations of 25 ng/L, 50 ng/L, and 100 ng/L) from 24 h postfertilization to 30 d posthatch induced VTG synthesis in a dose-dependent manner. Shorter periods of exposure to 100 ng/L estradiol-17β (24 h postfertilization to 10 or 20 d posthatch) similarly induced a vitellogenic response. This work demonstrates that fathead minnow are sensitive to estrogen and are able to synthesize VTG very early in development; this provides the basis for the adaptation of existing fish early-life-stage tests for the in vivo testing of estrogenic chemicals.
Combination toxicology of copper, zinc, and cadmium in binary mixtures: Concentration-dependent antagonistic, nonadditive, and synergistic effects on root growth in Silene vulgaris
Authors: Sharma Shanti S , Schat Henk , Vooijs Riet , Van Heerwaarden Luisa M
Published: March 2010

Using Silene vulgaris (Moench) Garcke as a test plant, the combination toxicology of Cu, Cd, and Zn was studied. Plants were exposed to single metals and binary metal mixtures in a factorial design. Root elongation after 3 d of exposure was used as a toxicity endpoint. The responses to mixtures were classified using nonaddition, response addition, and, where possible, concentration addition as reference models. In all the metal combinations tested, the nature of the joint effect appeared to be strongly concentration-dependent. The responses were approximately nonadditive (Cu/Zn, Cu/Cd) or antagonistic (Zn/Cd) with respect to root growth inhibition as long as the concentrations of both components of the mixture were kept within the slightly toxic range. As soon as one of the mixture components exceeded a critical level of toxicity, synergism was the predominant joint effect, even when the concentration of the other component was nontoxic under single-metal exposure. Further increases of the metal concentrations eventually decreased the degree of synergism, possibly as a result of increasing antagonisms at the level of metal uptake. The strongly synergistic effects of root-internal metals in the more concentrated mixtures seemed to be due to sensitizing secondary effects other than saturation of common cellular detoxification mechanisms.
An integrated evaluation of the persistence and effects of 4-nonylphenol in an experimental littoral ecosystem
Authors: Liber Karsten , Knuth Michael L , Stay Frank S
Published: March 2010

A comprehensive littoral enclosure study was conducted to assess the persistence and distribution of 4-nonylphenol (NP) in a littoral ecosystem, and to evaluate the compound's effects on resident aquatic biota. Enclosures with a mean (±SD) surface area and volume of 31.4 ± 3.3 m2 and 32.0 ± 6.4 m3, respectively, received eleven applications at 48-h intervals with one of four different rates of NP. This created a 20-d application period which was followed by a three to fourteen month observation period, depending on the endpoint measured. Mean ± SD NP concentrations in the water column measured 2 h after each application averaged 5 ± 4, 23 ± 11, 76 ± 21, and 243 ± 41 μg/L at nominal treatments of 3, 30, 100, and 300 μg/L, respectively. Persistence in the water column was relatively short, with a dissipation half-life estimated at ≤1.2 d. Persistence of NP in sediment and on macrophytes was substantially longer, with estimated half-lives of 28 to 104 d and 8 to 13 d, respectively. Zooplankton was the most sensitive group of organisms evaluated, with significant reductions in population abundances of some copepod taxa observed at the 23 ± 11-μg/L treatment. Fish survival was affected at 243 ± 41 μg/L. The most sensitive benthic macroinvertebrate taxon, Pisidium (Bivalvia) was affected at 76 ± 21 μg/L, but most taxa were only affected at the 243 ± 41-μg/L treatment. None of the assessed populations were affected at the 5 ± 4-μg/L treatment. Macrophytes and periphyton were not adversely affected by any of the treatments. Overall community composition, assessed at the family level or higher, was not affected at or below the 23 ± 11-μg/L treatment, but did exhibit substantial changes at the 243 ± 41-μg/L treatment. Some minor changes were observed at the 76 ± 21-μg/L treatment. The maximum acceptable toxicant concentration in the water column, based on protection of the most sensitive taxa in the test system, was estimated at ˜10 μg/L. Details on NP persistence and distribution within the enclosures, and detailed effects on zooplankton, benthic macroinvertebrates, and fish are described in four separate papers immediately following this overview.
Unifac modeling of multicomponent nonaqueous phase liquids containing polycyclic aromatic hydrocarbons
Authors: Peters Catherine A , Mukherji Suparna , Weber Walter J
Published: March 2010

Multicomponent nonaqueous phase liquid (NAPL) contaminants that are mixtures of polycyclic aromatic hydrocarbons (PAHs) are examined using UNIFAC. The NAPL phase activity coefficients for constituent compounds of four different coal tar materials are estimated. The group contribution approach is adapted to describe representative molecular structures of the uncharacterized fractions of the tar materials, determined from average molecular weights and nonparametric regressions of the functional group parameters against molecular weight. The molecular structure characterization of the tars elucidates the similar chemistry of the materials from different sites, despite their different chemical compositions. Nearly ideal behavior is predicted for most tar constituents, with the majority of activity coefficients in the range of 0.9 to 1.1. These results provide a firm theoretical basis for an assumption of NAPL-phase ideality for many tar constituents. The robustness of this conclusion is indicated through comparable results across different tar materials and through a sensitivity analysis of the effect of the estimated characteristics of the uncharacterized fractions.
Response of mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside minnow (Menidia beryllina) to changes in artificial seawater salinity
Authors: Pillard David A , Dufresne Doree L , Tietge Joseph E , Evans James M
Published: March 2010

Although marine organisms are adapted to naturally high concentrations of total dissolved solids (salinity) in their environment, abnormally high or low concentrations of ions can be toxic. Toxicity can result from aberrant levels of a single ion or from shifts in the entire spectrum of salts that comprise saltwater. To determine how marine organisms will respond to drastic swings in solution salinity and to provide a predictive tool to assess toxicity attributable to salinity, three common marine test organisms were exposed to balanced solutions ranging in salinity from near zero to more than 80%0. The organisms tested were mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside minnow (Menidia beryllina) Logistic regression was used to relate salinity to survival for each of the three test species. Survival of all three species was reduced at low and high salinities, although impacts to mysid shrimp at salinities of 4%0 or less were more pronounced than to either fish species. In high-salinity studies, mysid shrimp and inland silverside minnows had 48-h LC50s of approx. 45%0; a 48-h LC50 of nearly 70%0 was calculated for the sheepshead minnow. Mysid shrimp and sheepshead minnows were relatively consistent in their response to saline solutions, whereas silverside minnows were more variable in their response.
Effects of butyltin compounds on phagocytic activity of hemocytes from three marine bivalves
Authors: Bouchard Nicole , Pelletier Émilien , Fournier Michel
Published: March 2010

Effects of tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) on the in vitro phagocytic activity of hemocytes from three marine bivalve species, Mytilus edulis, Mya arenaria, and Mactromeris polynyma, were determined using flow cytometry. Phagocytosis was reduced with increasing doses of TBT and DBT. The toxicity of butyltins on hemocytes decreased in the order DBT > TBT > MBT, and comparison of the relative sensitivity of the three species showed that blue mussels (M. edulis) were more tolerant of butyltin compounds than both clam species. Toxicity mechanisms of butyltins are discussed and compared to those of other metals.
Organic pollutant characterization and toxicity testing of settling particulate matter by nanoinjection in sea trout (Salmo trutta) eggs
Authors: Ishaq Rasha , Åkerman Gun , Näf Carina , Balk Lennart , Bandh Cecilia , Broman Dag
Published: March 2010

A “nanoinjection” technique was used to expose sea trout (Salmo trutta) eggs to a toluene extract of settling particulate matter (SPM) and fractions thereof from the urban waters of Stockholm, Sweden. Total extract (unfractionated), fractions collected using fractionation on an open Florisil® column (F1–F4), high-performance liquid chromatography (HPLC) aminopropylsilica/2-(1-pyrenyl)ethyldimethylsilulated silica column (A1–A7 and A2/P1–P3), and recombined fractions of Florisil (F-Rec) and HPLC (A-Rec) were injected into fertilized sea trout eggs. Toxicity was evaluated on the basis of deformities at hatching and in larval stages and on the basis of larvae mortality. Chemical analysis, using gas chromatography–mass spectrometry, was performed on all HPLC fractions and indicated that major components of fractions A2/P1 and A3 through A7 were polycyclic aromatic hydrocarbons (PAHs) or their alkylated derivatives. Fraction A2/P2 contained non-ortho-chlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and some Cl-substituted PAHs. Deformities at hatching were observed mainly in the larvae exposed to fraction A-Rec. F2 showed the highest effect on larvae mortality, and both F-Rec and A-Rec showed antagonistic mechanisms. The frequency of deformities in larvae was highest in fractions A2/P2, F4, and A-Rec. Fractions A2/P1 and F1, which partly contained similar substances, showed similar effects on deformity at hatching and larvae mortality; however, F1 showed no effect on larvae abnormality compared with A2/P1. This could have been due to antagonistic mechanisms acting in F1.
Aquatic ecological risks posed by tributyltin in united states surface waters: Pre-1989 to 1996 data
Authors: Cardwell Rick D , Brancato Mary Sue , Toll John , Deforest David , Tear Lucinda
Published: March 2010

Acute and chronic risks to aquatic life from exposure to tributyltin (TBT) in surface waters were assessed probabilistically using more than 9 years of monitoring data. More than 50 sites around the United States were sampled, representing six saltwater regions and one freshwater (Lake Erie). Ambient TBT concentrations were compared to acute and chronic effect thresholds to estimate risks for each year (1986-1988 and 1992-1996), site type, and region. Site types comprised commercial harbors, shipyards, marinas, and fish/shellfish habitats proximate to these commercial areas. Tributyltin concentrations in surface waters have declined in all regions and site types since passage of the Organotin Antifouling Paint Control Act in 1988. No risks of acute toxicity have been suggested since 1994. Chronic risks have remained highest in marinas compared to other site types but have declined from a risk involving 25% of the species prior to 1989 to one involving 6% of the species in 1996. Risks associated with commercial harbors and shipyards have been similar (4-6%) since 1994. Chronic risks have been ≤1% in fish and shellfish habitats sampled <1 to 2 km from TBT sources. Risks in Galveston Bay, over all years (1-19%), have been greater than in the other regions (≤9%).
Ecological risk assessment in a large river-reservoir: 1. Introduction and background
Authors: Cook Robert B , Suter Glenn W , Sain E Riley
Published: March 2010

The U.S. Department of Energy initiated a remedial investigation of the Clinch River/Poplar Creek system Superfund Site in 1989. This site, located in eastern Tennessee near Oak Ridge, consists of 70 river kilometers and 40 km2 of surface area. The purpose of this study was to evaluate the nature and extent of contamination, perform an ecological and human health risk assessment, and evaluate possible remedial alternatives. This introductory article summarizes the environmental setting, the contamination history, and the study approach and provides some general results of the site characterization. Subsequent papers in this series describe the ecological risks to fish, piscivorous and insectivorous wildlife, and benthic invertebrates.
Ecological risk assessment in a large river-reservoir: 2. Fish community
Authors: Suter Glenn W Suter , Barnthouse Lawrence W , Efroymson Rebecca A , Jager Henriette
Published: March 2010

This paper summarizes the assessment of risks to fishes in the Clinch River Operable Unit due to contaminants released by the U.S. Department of Energy's activities on its Oak Ridge Reservation in Tennessee. This paper focuses on the most contaminated area, the Poplar Creek (PC) embayment. The assessment is of interest because of its use of five distinct lines of evidence: fish community surveys, fish body burdens, toxicity tests of ambient waters, suborganismal bioindicators, and single chemical toxicity tests. None of these lines of evidence provided unambiguous evidence of a significant risk, but the surveys indicated that the fish community in PC was depauperate, polychlorinated biphenyl body burdens may have been at toxic levels in catfish, one of the three tests of ambient water showed clear toxicity, some of the indicators were indicative of toxic effects, and concentrations that have been toxic in the laboratory were detected periodically. Interpretation was further complicated by upstream contamination of both the Clinch River and PC. The risk characterization was performed by evaluating each line of evidence separately and then weighing the evidence using an ecoepidemiological approach.
Ecological risk assessment in a large river-reservoir: 5. Aerial insectivorous wildlife
Authors: Baron Lisa A , Sample Bradley E , Suter Glenn W
Published: March 2010

Risks to aerial insectivores (e.g., rough-winged swallows, little brown bats, and endangered gray bats) were assessed for the remedial investigation of the Clinch River/Poplar Creek (CR/PC) system. Adult mayflies and sediment were collected from three locations and analyzed for contaminants. Sediment-to-mayfly contaminant uptake factors were generated from these data and used to estimate contaminant concentrations in mayflies from 13 additional locations. Contaminants of potential ecological concern (COPECs) were identified by comparing exposure estimates generated using point estimates of parameter values to NOAELs. To incorporate the variation in exposure parameters and to provide a better estimate of the potential exposure, the exposure model was recalculated using Monte Carlo methods. The potential for adverse effects was estimated based on the comparison of exposure distribution and the LOAEL. The results of this assessment suggested that population-level effects to rough-winged swallows and little brown bats are considered unlikely. However, because gray bats are endangered, effects on individuals may be significant from foraging in limited subreaches of the CR/PC system. This assessment illustrates the advantage of an iterative approach to ecological risk assessments, using fewer conservative assumptions and more realistic modeling of exposure.
Ecological risk assessment in a large river-reservoir: 7. Environmental contaminant accumulation and effects in great blue heron
Authors: Halbrook Richard S , Brewer Robert L , Buehler David A
Published: March 2010

Past plant operations and waste disposal on the Oak Ridge Reservation (ORR) have introduced an assortment of potentially harmful contaminants into the surrounding environment. Elevated concentrations of mercury (Hg) and PCBs have been found in fish collected from aquatic systems on the ORR, and a screening level risk assessment has identified piscivorous wildlife downstream from the ORR as being at risk. As a component of an ecological risk assessment of a large river-reservoir system, the great blue heron (Ardea herodias) was chosen as an endpoint species to evaluate potential adverse effects of contaminants on piscivorous wildlife using aquatic systems on or downstream of the ORR. Eggs and chick liver, muscle, and fat samples were collected from two heron colonies located on and two colonies located off the ORR. Samples were analyzed for PCBs, mercury, chromium, and arsenic to determine if differences existed among colonies. Mean mercury and PCB concentrations were greater in eggs and chick tissues collected from colonies located on the ORR. However, no biologically significant differences were observed in fecundity or in egg physical measurements or chick physiological measurements between study locations. The results of this study do not indicate that the contaminant burdens in great blue heron chicks and eggs have a detrimental effect on heron populations utilizing aquatic habitats on the ORR.