bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of trivalent chromium to early life stages of steelhead trout
Authors: Stevens Donald G. , Chapman Gary A. 
Published: March 2010

AbstractAcute and early life stage toxicity tests were conducted with trivalent chromium and steelhead trout (Salmo gairdneri). A 96-h LC50 of 4,400 μg/L chromium was obtained with two-month-old juvenile fish. Early life stage exposure from newly fertilized eggs to 30-d post-swimup produced complete mortality at 495 μg/L, and significantly reduced survival to hatch and to the end of the test at 157 and 89 μg/L, respectively. An early life stage test started with eyed eggs produced similar results, with hatching survival significantly reduced at 271 μg/L. An acute test conducted with fish surviving the early life stage test showed that no acclimation resulted from previous chromium exposure.
Mineralization and sorption of p-nitrophenol in estuarine sediment
Authors: Siragusa Gregory R. , Delaune Ronald D. 
Published: March 2010

Abstract
The sorption and mineralization of p-nitrophenol were studied in sediment from a Louisiana Gulf Coast estuary. The rate of mineralization of p-nitrophenol, as determined by 14CO2 release, was found to be several orders of magnitude faster under oxidized (aerobic) conditions than under reduced (anaerobic) conditions. The results also indicated a rapid sorption of the compound from the water column by the sediment and only minimal re-release. Due to sorption from the water columns and slow degradation of the compound in an anaerobic system, such as in bottom sediment, it is likely that this compound would persist for years in reduced estuarine sediment.
Control of interferences in the analysis of human adipose tissue to 2,3,7,8-tetrachlorodibenzo-p dioxin (TCDD)
Authors: Patterson D. G. , Holler J. S. , Groce D. F. , Alexander L. R. , Lapeza C. R. , O'Connor R. C. , Liddle J. A. 
Published: March 2010

Abstract
While developing a method to analyze human adipose tissue for 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) at the 1 ppt level, we observed several peaks with all of the analytical characteristics of TCDDs in the analyses of wipe tests and blank, quality control, and human adipose samples at concentrations equal to the low part-per-trillion level in a 10 g sample. The source of these contaminants was established to be a cleaning solution used to wash the floors in the laboratory performing the analysis.
Sublethal effects of biologically treated petroleum refinery wastewaters on agonistic behavior of male orangespotted sunfish, Lepomis Humilis (girard)
Authors: Petersen James C. , Burks Sterling L. , Miller Rudolph J. 
Published: March 2010

Abstract
Pairs of orangespotted sunfish were exposed to oil refinery wastewaters in acute, non-lethal toxicity tests. Frequencies of agonistic behaviors (approaches, fin erections, tail beats, operculum spreads, chases, bites and avoidances) were determined initially after a 10-d exposure to control water and then again after a 10-d exposure to the wastewaters. Changes in frequency were compared with changes in frequency for pairs of fish exposed to control water for both 10-d periods.
Pairs of fish were observed for 60 min following each of the two 10-d exposures. Frequencies during the initial 15 and 30 min of the period and during the entire 60-min period were determined. For wastewater-exposed fish, the frequency of each behavior generally decreased following the 10-d exposure to wastewater. For fish exposed only to the control water, each behavior generally increased in frequency following the second 10-d period. The change in frequency for wastewater-exposed fish was significantly (p &lt; 0.05) different from that for control fish for approaches, fin erections, chases, bites and avoidances at one or more of the three lengths (15, 30 and 60 min) of observation.
Modeling the impact of conservation tillage practices on pesticide concentrations in ground and surface waters
Authors: Donigian Anthony S. , Carsel Robert F. 
Published: March 2010

Abstract
To analyze the environmental fate and migration of pesticides applied to croplands as they are affected by conservation tillage practices, pesticide models for leaching, surface water and ground water were selected and an application method was developed. Fourteen different pesticides applied to corn and soybeans were analyzed to determine probable concentrations in ground water and surface water under conventional tillage, reduced tillage and no tillage practices; the Lake Erie Basin was the study site. Surface runoff loadings and concentrations decreased under the conservation tillage scenarios, but ground water loadings and concentrations increased as a result of the decreased runoff and increased ground water recharge. Reduced tillage decreased surface runoff loads and concentrations by about 50% as compared with conventional tillage, and no tillage resulted in another 20% reduction. The pesticides with the highest surface runoff loads and concentrations were those with Koc values generally less than 200 ml g−1 and root zone half-lives greater than 40 d.
For ground water, only four pesticides demonstrated mean annual loadings high enough to require estimation of resulting ground water concentrations. These four compounds also had the highest surface water loadings and are characterized by Koc values of 100 ml g−1 or less and root zone half-lives of 35 d or longer.
Ground water concentrations for all four compounds were low, with carbofuran showing the highest concentrations (approaching 1.0 ppb). Next was dicamba, but its concentrations were four to five orders of magnitude less. Sensitivity analyses for carbofuran indicated that the concentrations could be at least one order of magnitude higher, depending on assumptions related to decay rate, hydraulic conductivity and other hydrogeologic parameters.
Use of respiratory-cardiovascular responses of rainbow trout (Salmo gairdneri) in identifying acute toxicity syndromes in fish: Part 1. pentachlorophenol, 2,4-dinitrophenol, tricaine methanesulfonate and 1-octanol
Authors: McKim James M. , Schmieder Patricia K. , Carlson Richard W. , Hunt Evelyn P. , Niemi Gerald J. 
Published: March 2010

Abstract
An in vivo fish model was adapted to monitor respiratory-cardiovascular responses of spinally transected rainbow trout exposed to acutely toxic aqueous concentrations of two uncouplers of oxidative phosphorylation, pentachlorophenol (PCP) and 2,4-dinitrophenol (DNP), and two narcotics, tricaine methanesulfonate (MS-222) and 1-octanol. The most evident toxic response to the uncouplers was a rapid 150 to 200% increase in ventilation volume (VG) and oxygen consumption (VO2) over the entire survival period. This caused an initial increase in total arterial oxygen (TaO2) content of the blood, which then fell slowly as the tissues used more and more oxygen to generate ATP. Arterial blood pressure (BPa) and other blood measurements did not change appreciably in response to PCP, yet DNP caused increases in hematocrit (Hct) and hemoglobin (Hb) and slight decreases in total arterial carbon dioxide (TaCO2) and arterial pH (pHa). In contrast to the uncouplers, the response of the respiratory-cardiovascular system of trout to toxic levels of narcotics was a dramatic slowing of all respiratory-cardiovascular functions. While VG and VO2 decreased 40 to 50% from predose levels, oxygen utilization (U) increased 20 to 30%. Ventilation rate (VR) declined initially and then increased slowly until death occurred, but remained within the control range. As respiration declined TaCO2 significantly decreased, as did pHa. In response to hypoxia, Hct increased substantially, and Hb increased slightly only in the 1-octanol exposure. A rapid 40 to 50% drop in heart rate (reflex bradycardia) was also observed. The final phase of toxicity caused by both uncouplers and narcotics appeared to eventually produce acute tissue hypoxia, with a generalized loss of respiratory-cardiovascular coordination, and finally respiratory paralysis. Individual principal component analyses of the cardiovascular-respiratory responses of fish exposed to the first two principal components explained 68 to 76% of the variation in the 18 parameters analyzed. A two-dimensional diagram of the first two principal components illustrated this multivariate response and the increased variability in the responses of exposed fish as compared with control fish. The general sets of responses described for these two fish acute toxicity syndromes have provided the initial information necessary to group similar responses caused by other chemicals into a fish uncoupler syndrome, a fish narcosis syndrome or some new syndrome.
Arsenic sedimentation along the slope of a lake basin
Authors: Siami Mehdi , McNabb Clarence D. , Batterson Ted R. , Glandon Robert P. 
Published: March 2010

Abstract
Lake Lansing, Michigan was treated with sodium arsenite for macrophyte control in 1957. Seven 1.5-m sediment cores were taken along a line through the littoral zone to the deepest portion of the lake and analyzed for arsenic. In each core, arsenic concentrations going from the surface downward increased to some maximum and then receded to background. Depth of peak concentrations followed two patterns: three littoral cores showed peak arsenic at 0.13 m from the sediment surface, and four cores from progressively deeper portions of the lake showed a regular decrease in peak depth from 0.32 m to 0.17 m. Sediment accumulation rates were calculated along this transect. Particle-size sorting of sediments along this slope was also measured. This work suggested that sediments originated from wetland vegetation at the edge of the lake. Turbulent movement of water in the shallows caused suspension and down-slope movement of small particles. Fewer particles of wetland origin were available for sedimentation beyond the region of highest fallout (3.75 m), thus accounting for progressively lower sedimentation rates in deeper portions of the basin. A model was developed to predict the time it would take for surface sediments to reach pretreatment concentrations of arsenic levels; for Lake Lansing it would be more than 100 years.
Kinetic studies of the reduction of aromatic AZO compounds in anaerobic sediment/water systems
Authors: Weber Eric J. , Lee Wolfe N. 
Published: March 2010

Abstract
The reductive transformation of azobenzene and selected derivatives was investigated in anaerobic sediment/water systems. The azo compounds exhibited pseudo-first-order disappearance kinetics through at least three half-lives. The reduction kinetics of these compounds was studied as a function of their reduction potential and sediment/water distribution coefficient. There was no apparent correlation between the observed disappearance rate constant and reduction potential. In general, as the distribution coefficient increased, the rate of reduction decreased. Values for the pseudo-first-order rate constant for disappearance ranged from 5.11 × 10−3 min−1 for methyl red to 6.03 × 10−6 min−1 for 4,4′-dichloroazobenzene. Removal of the solid phase from the sediment/water samples gave a filtrate with little or no reactivity. Chemical sterilization of the sediment/water sample with formaldehyde and treatment with m-cresol, a dehydrogenase inhibitor, or sodium azide, a metabolic inhibitor, had little effect on the observed reduction rate constants for azobenzene, indicating an abiotic reduction process. Heat sterilization indicated that the reducing agent was heat labile. In studies with 4,4′-dimethoxyazobenzene, the observed rate constant for reduction increased with increasing sediment concentration. Based on the results of these studies, a model for the reduction process was developed that incorporates a nonreactive sorptive sink and a reactive site, both of which are associated with the sediment.
Acute toxicity of permethrin or glyphosate pulse exposure to larval white sucker (catostomus commersoni) and juvenile flagfish (jordanella floridae) as modified by age and ration level
Authors: Holdway D. A. , Dixon D. G. 
Published: March 2010

Abstract
A factorial design was used to determine the effects of age (2, 4, and 8 d for flagfish; 13, 20, and 26 d for white sucker) and ration (fed or unfed) on the acute toxicity of permethrin pulse exposure. A similar design was used to evaluate the acute toxicity of glyphosate to flagfish. Relative tolerance was assessed by determining the 2-h pulse-exposure concentration causing 50% mortality (PE LC50) over the subsequent 96 h. Age at exposure and the presence or absence of food modified the toxicity of permethrin to both flagfish and white sucker. White sucker were consistently less tolerant of permethrin than flagfish. Fed and unfed 8-d-old flagfish, as well as unfed 2-d-olds, showed equivalent levels of permethrin tolerance, with respective 96-h PE LC50s of 0.57, 0.54, and 0.68 mg L−1. They were significantly less tolerant than 4-d-old unfed juveniles (2.97 mg L−1), which were in turn significantly less tolerant than 2- and 4-d-old fed juveniles, whose respective 96-h PE LC50s were 5.55 and 7.91 mg L−1. Unfed white suckers were less tolerant than fed white suckers at all ages tested. Unfed white suckers at 13 d (96-h PE LC50, 0.002 mg L−1) and 20 d (0.001 mg L−1) were significantly less tolerant than unfed fish at 26 d (0.172 mg L−1) and fed fish at 13 d (0.184 mg L−1), which were more tolerant than 20-d-old fed fish (0.010 mg L−1). Fed fish at 26 d of age were the most tolerant (3.668 mg L−1). Glyphosate proved to be relatively nontoxic to flagfish up to 30 mg L−1. No mortality was observed during the bioassays with 2- and 4-d-old fed and starved fish. Fed 8-d-olds (96-h PE LC20, 29.6 mg L−1) were significantly more tolerant of glyphosate than were unfed 8-d-olds (96-h PE LC20, 2.94 mg L−1). The sharply delineated periods of permethrin sensitivity are discussed with reference to the theory of saltatory ontogeny.
Toxicokinetics of chlorobenzenes in fish
Authors: Van Hoogen Geertjan , Opperhuizen Antoon 
Published: March 2010

Abstract
In acute toxicity tests with guppies (Poecilia reticulata), lethal effects were found for 1,2,3-tri-, 1,2,3,4-tetra-, and pentachlorobenzene if the concentrations in the fish approached 2.0 to 2.5 μmol/g fish. The lethal concentrations were equal for the three test compounds and were independent of the exposure conditions. The lethal concentrations of chlorobenzenes in guppies were equal to those previously found for polychlorinated biphenyls in goldfish but approximately two times higher than those found for chlorinated phenols in goldfish. Combinations of the exposure times and exposure concentrations causing mortality can be described and readily predicted with a first-order bioconcentration model.
Comparison of breaking strength and shell thickness as evaluators of eggshell quality
Authors: Bennett Jewel K. , Ringer Robert K. , Bennett Richard S. , Williams Bill A. , Humphrey Philip E. 
Published: March 2010

Abstract
The shell quality of eggs produced by northern bobwhite (Colinus virginianus) dosed with sulfanilamide was evaluated by a compression breaking strength test and by the shell thickness measurements that are used in the U.S. Environmental Protection Agency avian reproduction test to determine the effect of a chemical substance on eggshells. The relative sensitivities of the two methods in detecting shell quality changes in sulfanilamide-treated quail were compared by relative response ratios, calculated as treatment period response divided by pretreatment values. The ratios demonstrated a clear shell weakening response and a less apparent shell thinning response. Significant differences in shell thickness of eggs from sulfanilamide-treated hens and those from control hens were not demonstrated (α = 0.32 and 0.34), although highly significant differences in shell strength were demonstrated (α &lt; 0.0001). Scanning electron micrographs of weak shells of normal thickness revealed abnormal ultrastructure, usually poorly formed mammillae. Obtaining both shell thickness and shell strength information may provide better means to evaluate a chemical's effect on shell quality.
Responses of polychaetes to cadmium-contaminated sediment: Comparison of uptake and behavior
Authors: Olla B. L. , Estelle V. B. , Braun G. , Swartz R. C. , Studholme A. L. 
Published: March 2010

Abstract
The burrowing behavior of three polychaete species, Nereis virens Sars, Glycera dibranchiata Ehlers and Nephtys caeca Fabricius, was examined after variable exposure periods (7, 14, 21 and 28 d) to sediment contaminated with a cadmium concentration of about 40 mg kg−1 (dry weight). Most comparisons of burrowing times and rates between exposed and unexposed worms were not statistically significant. Those that were significant were relatively minor, e.g., a maximum reduction in burrowing time of 6.3 s, and probably would have little ecological relevance. The feeding behavior of G. dibranchiata on the polychaete Euzonus mucronata was not affected by a 28-d exposure to cadmium-contaminated sediment. Uptake of cadmium varied among the three species. After 28 d of exposure, cadmium body burdens were highest for N. virens (319mg kg−1), intermediate for G. dibranchiata (120 mg kg−1) and lowest for N. caeca (39 mg kg−1). This potential for bioaccumulation and survival in cadmium-contaminated sediment indicates that some polychaete species like N. virens may be an amplified source of cadmium for their crustacean, fish and avian predators.
Attached-algal abundance altered by individual and combined treatments of zinc and pH
Authors: Genter Robert B. , Cherry Donald S. , Smith Eric P. , Cairns John 
Published: March 2010

Abstract
Attached-algal communities were employed to test the U.S. Environmental Protection Agency's (EPA) guidelines for zinc (Zn) and pH. The EPA criterion for Zn is 0.047 mg/L, and the EPA effluent standard generally requires that discharge water fall between pH 6 and 9. The experiment was designed to determine whether algal community composition and abundance would be altered by (a) pH 6 or 9, (b) 0.05 mg/L Zn, or (c) the combination of pH 6 or 9 and 0.05 mg/L Zn. Stream mesocosms were continuously supplied with natural water from the New River, Virginia, USA. Established (12-d colonization) communities on artificial substrates were sampled on days 0, 5, 10, 20, and 30 after treatment began on 9 July 1985. Total algal abundance increased in pH 6 treatment. Treatments of pH 6 and 0.05 mg/L Zn reduced abundance of species characteristic of control mesocosms. These species were replaced by species characteristic of 0.05 mg/L Zn and pH 6 mesocosms. These changes occurred even though these levels are considered “safe” by EPA. Community composition did not differ significantly between ambient (pH 8.5) and pH 9 treatments. Although further research is needed, one might speculate that this change in community composition may have potential ecosystem effects by reducing food quality from diatoms to green algae that may inhibit higher level consumers.
Sequential sampling of plasma cholinesterase in mallards (Anas platyrhynchos) as an indicator of exposure to cholinesterase inhibitors
Authors: Fairbrother Anne , Bennett Richard S. , Bennett Jewel K. 
Published: March 2010

Abstract
The use of sequential measurements of plasma cholinesterase (ChE) activity for monitoring exposure to organophosphorus pesticides was investigated in the mallard (Anas platyrhynchos). At the onset of incubation, birds were assigned to treated (400 ppm methyl parathion in the diet), pair-fed (same daily food allotment on a g/kg/d basis as consumed by the treated bird of the pair), control or nonincubating control groups. Blood samples were collected weekly during egglaying and every 3 d during incubation periods. Both plasma and brain samples were taken on day 24 of incubation. Plasma ChE was more variable than brain ChE among the birds and there were no significant correlations (p &gt; 0.05) between plasma and brain samples within treatment groups. Reduced food consumption during incubation did not affect plasma ChE activity (p = 0.77). Birds that abandoned their nests had significantly increased (paired t = -2.39, d.f. = 9, p &lt; 0.05) ChE activity at the time of abandonment. There were significant differences (p &lt; 0.01) in plasma ChE activity between untreated birds, but within-bird variation was 2 and 11 times less than betweenbird variation during egg-laying and incubation, respectively. Methyl parathion significantly (p &lt; 0.0001) reduced plasma ChE activity. Measurement of plasma ChE activity provides a noninvasive, nonlethal technique for assessing the exposure of animals to ChE inhibitors.
Genetic variation in laboratory and field populations of the midge, Chironomus tentans fab.: Implications for toxicology
Authors: Woods Paul E. , Paulauskis Joseph D. , Weigt Lee A. , Romano Michael A. , Guttman Sheldon I. 
Published: March 2010

Abstract
Chironomus tentans larvae are used extensively in toxicoiogical bioassays. Gel electrophoresis was performed on seven laboratory populations and a wild population of C. tentans. Direct count heterozygosity was significantly different between wild and laboratory populations, as well as among laboratory populations. Percent polymorphic loci demonstrated the same trends but were marginally nonsignificant. The wild midge population had seven unique alleles and a significantly higher level of heterozygosity. Despite these differences the wild population was genetically similar to laboratory populations. The impact of significant differences in Chironomus genetic variability on toxicoiogical bioassays is discussed.
Comparison of aqueous and solid-phase uptake for hexachlorobenzene in the tellinid clam Macoma nasuta (conrad): A mass balance approach
Authors: Boese Bruce L. , Lee Ii Henry , Specht David T. , Randall Robert C. , Winsor Martha H. 
Published: March 2010

Abstract
The uptake of sediment-associated hexachlorobenzene (HCB) by the deposit-feeding clam Macoma nasuta (Conrad) was determined using a clam ventilation chamber. Clams were exposed to [14C]HCB-dosed sediment, and the 14C amounts were measured in inhalant and exhalant waters, fecal pellets and soft tissues. The volume of water the clam ventilated and the amount of fecal pellets produced were measured. The contributions of 10 possible uptake routes to HCB tissue residues were estimated using a bioenergetic-based bioaccumulation model. Mass balance results indicate that uptake of HCB by the gut from ingested solids was the single most important route, accounting for 63 to 84% of HCB tissue residues. The next largest route was uptake from interstitial water ventilated across the gills, which accounted for 11 to 12% of tissue residues. Uptake of HCB from overlying water was minimal. These results indicate that sediment-bound HCB is bioavailable to benthic deposit feeders such as Macoma and supports the contention that ingested sediment is an important uptake route for highly lipophilic pollutants.