bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of arsenate on growth and physiology in mallard ducklings
Authors: Camardese Michael B. , Hoffman David J. , LeCaptain Leonard J. , Pendleton Grey W. 
Published: March 2010

Abstract
Arsenic (As) has been found at elevated concentrations in irrigation drainwater and in aquatic plants utilized by waterfowl. Mallard (Anas platyrhynchos) ducklings received an untreated diet (controls) or diets containing 30, 100 or 300 ppm As added as sodium arsenate. After 10 weeks blood and tissue samples were collected for biochemical and histological examination. Arsenic accumulated significantly in brain and liver of ducklings fed 100 or 300 ppm but did not result in histopathological lesions. The 300-ppm dietary As concentration decreased overall growth (weight gain) in males, whereas all concentrations of As decreased overall growth and rate of growth in females. Food consumption was less during the first three weeks in the 300-ppm group and during the second week for the 100-ppm group compared to controls. Plasma sorbitol dehydrogenase activity and plasma glucose concentration were higher in the 300-ppm group compared to controls. Plasma triglyceride concentration increased in all As-treated groups. Brain ATP was lower in the 300-ppm group and sodium/potassium-dependent ATPase activity was higher in the 30- and 100-ppm groups. Hepatic glutathione peroxidase activity was lower in the 300-ppm group and malondialdehyde lower in all treatment groups. All treatment levels caused elevation in hepatic glutathione and ATP concentrations. These findings, in combination with altered duckling behavior (increased resting time), suggest that concentrations of As that have been found in aquatic plants (up to 430 ppm dry weight) could adversely affect normal duckling development.
Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality
Authors: Henny Charles J. , Bennett Jewel K. 
Published: March 2010

Abstract
Data from a 1986 field study of white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p, p'-DDE, hereafter referred to as DDE. Eggs from 80 nests (one egg/nest) were tested for shell strength and thickness. Egg contents were analyzed for organochlorines, mercury and selenium; productivity at each nest (minus one egg) was monitored in the field. DDE-DDT concentrations in the eggs ranged from none detected (&lt;0.1) to 29 ppm (wet weight). Shell thickness and shell strength were both negatively correlated with DDE (−0.60, −0.61, respectively), but shell strength deteriorated at a faster rate than shell thickness. Scanning electron micrographs indicated the deterioration in strength was related to changes in ultrastructure as well as to decreased thickness. Fourteen eggs with &lt;0.40 ppm DDE were used to exemplify normal “control” eggs. Of the eggs with higher concentrations of DDE (i.e., ≥0.40 ppm), 11 of 66 were thinner (&gt;2 SD below “control” mean) than normal, 11 of 59 were weaker than normal and 7 eggs were cracked so their strength could not be tested, although thickness was measured. Therefore, 17% of the eggs with ≥0.40 ppm DDE were thinner than normal and 27% were either weaker than normal or cracked. Further, six eggs (four with ≥15 ppm DDE) did not have abnormally thin shells, but did have abnormally weak shells. Nests with abnormal test eggs (thinner, weaker or cracked) produced fewer young than nests with normal eggs. Use of the shell strength parameter provides additional information for better evaluations of reproductive problems. The potential utility of monitoring eggshell quality goes beyond evaluating effects of organochlorines since recent work indicates that other environmental hazards can affect shell quality.
Lead, cadmium and other metals in scandinavian surface waters, with emphasis on acidification and atmospheric deposition
Authors: Steinnes Eiliv 
Published: March 2010

Abstract
Long-range atmospheric transport of pollutants affects the chemistry of heavy metals in natural waters in several ways. First, the direct atmospheric supply of some metals to lakes and their catchments may add strongly to the total burden of these metals in the lake ecosystems. Second, the acidity of the precipitation may enhance the metal fluxes by dissolution of metals originating from mineral material in the catchment or previously supplied by atmospheric deposition and fixed to surface soil or sediment. Furthermore, the acidification of surface waters interferes strongly with the speciation of the metals in the water. The southern part of Scandinavia is considerably influenced by long range atmospheric transport from other parts of Europe. The present paper is a review of recent work in this region related to the occurrence and chemical behavior of lead, cadmium and other trace metals in natural surface waters, with emphasis on the supply from atmospheric deposition. The impact of acidification on the mobility and chemical speciation of the metals is briefly discussed.
Environmental factors affecting the formation of methylmercury in low pH lakes
Authors: Winfrey Michael R. , Rudd John W. M. 
Published: March 2010

Abstract
Recent studies have demonstrated elevated levels of mercury in fish from remote, low alkalinity and low pH lakes. The mechanisms of this enhanced bioaccumulation are poorly understood, but the amount of methylmercury produced in a lake can play a major role. Decreased pH stimulates methylmercury production at the sediment-water interface and possibly in the aerobic water column. Decreased pH also decreases loss of volatile mercury from lake water and increases mercury binding to particulates in water – factors that may increase methylation at low pH by enhancing the bioavailability of mercury for methylation. In anoxic subsurface sediments, decreased pH decreases the rate of mercury methylation, suggesting that methylmercury formation in the water column and at the sediment-water interface may be most important in acidified lakes. Sulfate-reducing bacteria are important mercury methylators in acidified lakes. Whether enhanced sulfate reduction stimulates methylmercury production in low pH lakes is presently unclear, although most of the available data do not support this hypothesis.
Mercury accumulation in yellow perch in wisconsin seepage lakes: Relation to lake characteristics
Authors: Wiener James G. , Cope W. Gregory , Rada Ronald G. 
Published: March 2010

Abstract
We studied relations between lacustrine characteristics and the total mercury (Hg) content of calendar age-2 yellow perch (Perca flavescens) in 10 seepage lakes in north-central Wisconsin. Mean concentrations and burdens (masses) of Hg in whole perch varied widely among lakes, were negatively correlated with lake pH and were positively correlated with total Hg concentration in surficial profundal sediment. Approximately 80 to 90% of the variation in Hg concentration and burden in whole perch was explained with multiple regressions containing two independent variables: either lake pH or alkalinity, and Hg concentration in surficial sediment. Variation among lakes in the Hg concentration in yellow perch was unrelated to their relative rates of growth. The mean concentration of Hg in axial muscle tissue of age-5 walleyes (Stizostedion vitreum vitreum) from five of the study lakes was highly correlated with the mean concentration in whole age-2 perch in the same lakes. We hypothesized that the high Hg concentrations often seen in piscivorous fish in low-alkalinity lakes (relative to high-alkalinity lakes) is at least partly due to a greater dietary intake of Hg in such waters. Furthermore, the analysis of small yellow perch—the preferred prey of adult walleyes and an important forage species for many predatory fishes in the north-central United States—may be an effective approach to assessing Hg bioavailability in the region's lakes.
Mineralization of linear alkylbenzene sulfonate (las) and linear alcohol ethoxylate (lae) in 11 contrasting soils
Authors: Knaebel David B. , Vestal J. Robie , Federle Thomas W. 
Published: March 2010

Abstract
The microbial mineralization of [U-14C-ring] linear alkylbenzene sulfonate (LAS) and [U-14C-ethoxylate] linear alcohol ethoxylate (LAE) was examined in 11 soils. These soils differed in their physical-chemical properties and were obtained from geographically distinct locations. With one exception, they had no previous exposure to synthetic surfactants. Soil samples were amended with trace levels (50 ng/g soil) of each 14C surfactant, and evolution of 14CO2 was measured over time. When appropriate, the data were fitted to a first-order production equation, and first order rate constants and asymptotic yields of 14CO2 were estimated using nonlinear regression. Both surfactants were mineralized without a lag period in every soil tested. Yields ranged from 16 to 71% and 30 to 69% for LAS and LAE respectively. First-order rate constants ranged from 0.14 to 0.63 for LAS and 0.07 to 0.62 for LAE. Mean half-life (across all soils) was 2 d for both surfactants. Community microbial activity, measured as the rate of acetate incorporation into lipids, did not correlate with either the rate or extent of surfactant mineralization. Subjecting these soils to cycles of wetting and drying in the laboratory prior to testing in most cases resulted in more rapid and extensive mineralization. These results indicate that microbial communities in soils have an indigenous ability to degrade low concentrations of LAS and LAE. This ability appears to be ubiquitous since it is present in a wide array of soil types from various locations. In addition, laboratory experiments involving wetting and drying of soils indicated that both the rate and extent of mineralization may be affected by climatological events.
Copper toxicity to Paratya australiensis: III. Influence of dissolved organic matter
Authors: Daly Helen R. , Jones Michael J. , Hart Barry T. , Campbell Ian C. 
Published: March 2010

Abstract
The influence of dissolved organic matter on the toxicity of copper to the Australian freshwater shrimp, Paratya australiensis, was measured using water collected from three sites in Victoria, Australia. A two-ligand model was used to describe copper complexation in these test waters. The binding characteristics of the ligands (i.e., total ligand concentrations and conditional stability constants) were determined using a method combining ion selective electrode and anodic stripping voltammetry.
Ion selective electrode measurements and the two-ligand model were each used to estimate the concentration of copper(II) (the major toxic species) at the LC50 values. Both methods overestimated by a factor of approximately 1.5 to 3 the expected copper(II) concentration at the LC50 values, based on earlier experiments in Melbourne tap water. The agreement seems remarkably good given the many assumptions used in making the comparison and the difficulties encountered with the use of ion selective electrodes in natural waters.
Comparison of measured instream biological responses with responses predicted using the ceriodaphnia dubia chronic toxicity test
Authors: Eagleson Kenneth W. , Lenat David L. , Ausley Larry W. , Winborne Ferne B. 
Published: March 2010

Abstract
Instream toxicity was predicted with whole effluent toxicity tests. These results were then compared to the observed instream response of the aquatic community. Forty-three comparisons were conducted in freshwater flowing systems using Ceriodaphnia dubia chronic toxicity test procedures and standardized qualitative sampling of benthic macroinvertebrates. In 88% of the comparisons there was agreement between both measures. These data suggest that the use of effluent toxicity testing results as a regulatory tool is effective and appropriate. Comparisons used whole effluent toxicity limitations similar to those being written in North Carolina's NPDES permits for discharge to surface waters.
Yolk retinoids (vitamin a) in eggs of the herring gull and correlations with polychlorinated dibenzo-p-dioxins and dibenzofurans
Authors: Spear Philip A. , Bourbonnais Diane H. , Moon Thomas W. , Norstrom Ross J. 
Published: March 2010

Abstract
Little is known of the combined effects associated with chronic, low-level exposure of wildlife to the polyhalogenated dibenzo-p-dioxins, dibenzofurans, certain biphenyls and other related compounds. To examine possible effects upon egg yolk retinoids, herring gull (Larus argentatus) eggs were collected at early (i.e., days 2–12) and late (i.e., approximately day 20) phases of incubation. Analysis of egg yolks by reversed-phase high-performance liquid chromatography revealed compounds that comigrated with all-trans-retinol and all-trans-retinyl palmitate standards. The retinol concentration and the molar ratio of retinol to retinyl palmitate changed significantly between the early and late phases of incubation. Within the 2- to 12-d period of incubation, however, retinoid values were constant. Gull eggs were collected from two breeding colonies on the Great Lakes in 1986 and from five colonies in 1987. In 2- to 12-d eggs, retinol and retinyl palmitate concentrations were significantly different between gull colonies. The molar ratio of retinol to retinyl palmitate was significantly different between colonies and correlated with several indices of polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations quantified in gull eggs from these collection sites. Significant correlations existed between the molar ratio of retinoids and (a) 2,3,7,8-TCDD concentration, (b) toxic equivalents of PCDDs and PCDFs and (c) the sum of PCDD and PCDF concentrations. These results are discussed in the context of sensitive, bioeffects monitoring.
Slowly reversible sorption of aliphatic halocarbons in soils. II. Mechanistic aspects
Authors: Pignatello Joseph J. 
Published: March 2010

Abstract
The mechanism of formation and release of highly immobilized residues of some small nonpolar halogenated hydrocarbons in two surface soils, a stream sediment and an aquifer sediment was investigated. The labile sorbed fractions of compound were removed from treated soils by purging to infinite dilution in aqueous suspensions for 96 h. The remaining slowly reversible (residual) fraction of compound in the soil was quantitated as a function of prepurge sorption conditions. The residual increased nonlinearly with sorption equilibration time and applied concentration. Residuals in whole soils and whole soils pretreated with H2O2 were correlated with soil organic carbon. Among wet-sieved particle size fractions, however, the organic carbon-based concentrations followed the order, sand &gt; silt &gt;&gt; clay. Also, some residual was associated with undecomposed plant matter. Release of the residual into water was greatly increased by pulverization of the soil and by acidification of the soil suspension. The results indicate that the slow release of the residual fraction is caused by molecular diffusion from remote sites in the soil organic matter matrix. Mineral surface and clay interlayer adsorption were ruled out by the finding of low residuals in the clay-sized particles. However, the mineral fraction plays an important role by shielding some of the organic matter in interstitial pores of particle aggregates from equilibrium with bulk solution.
Methods for assessing fertilization and embryonic/larval development in toxicity tests using the california mussel (Mytilus californianus)
Authors: Cherr Gary N. , Shoffner-Mcgee Julie , Shenker Jonathan M. 
Published: March 2010

Abstract
The fertilized eggs, embryos and larvae of the California mussel (Mytilus californianus) were used to develop methods for assessing fertilization and larval development rates, and for conducting toxicity tests in standard exposure chambers and small volume (3 ml) chambers. Because the sperm/egg ratio resulting in high monospermic fertilization rates varied among females, the “optimal” ratio for each female was predetermined in an aliquot of eggs prior to fertilizing the entire batch for bioassay use. The fluorescent DNA probe Hoechst 33342 was used to rapidly differentiate unfertilized, monospermic and polyspermic eggs. Following fertilization of entire batches of eggs based on the predetermined sperm/egg ratio, monospermic fertilization rates of &gt;90% were readily achieved. Fertilized embryos were then used in bioassays conducted in beakers or tissue-culture chamber slides (mini chambers), which could be viewed directly on the microscope. The response of the embryos and larvae to the metabolic inhibitor sodium azide was assessed in both types of test chambers. At 96 h postinsemination at 12°C, veliger or nonveliger larvae were assessed using polarization microscopy to determine the presence or absence of a complete shell. No significant difference in the response to sodium azide was detected between the beakers and mini chambers. This study demonstrates that M. californianus is suitable for static embryo/larval toxicity tests, and that small volume chambers allow successful larval development and eliminate the need for subsampling of larger test chambers. We also demonstrated the value of assessing fertilization rates prior to conducting the bioassay, and present an improved method for examining larval shell development using polarization microscopy.
Avoidance of selenium-treated food by mallards
Authors: Heinz Gary H. , Sanderson Caroline J. 
Published: March 2010

Abstract
Adult, male mallards (Anas platyrhynchos) were given a choice between a control diet and a diet containing 5, 10 or 20 ppm selenium as selenomethionine dissolved in water and mixed into the diet. At 10 and 20 ppm, selenium-treated diets were avoided. Avoidance appeared to be caused by a conditioned response, probably to illness caused by the selenium and not to an aversion to the taste of the selenium.
PCB movement, dechlorination, and detoxication in the acushnet estuary
Authors: Brown John F. , Wagner Robert E. 
Published: March 2010

Abstract
Congener-specific analyses of the PCBs in Acushnet Estuary (New Bedford, MA) sediments and waters were undertaken to identify the PCB alteration and transport processes occurring in coastal marine sediments. These analyses indicated that (a) the PCBs deposited at the sediment sites sampled had originally consisted of Aroclors 1242 and 1254, in widely varying proportions; (b) these PCBs had undergone vertical movement within the sediments, rather than remaining stratified, but not horizontal translocation between sites; (c) they had also undergone extraction into the water, albeit at declining rates, with some consequent changes in composition but (d) the major compositional change was caused by a previously unreported type of reductive dechlorination process, designated Process H. This presumably anaerobic microbial process, subsequently identified at several other locations as well, had selectively removed non-ortho chlorines from most of the higher PCB congeners, especially those associated with acute toxic effects. It appeared to have begun near the upper end of the estuary and not yet reached its lower portions, thus providing a marker for tracing the origin of the PCBs in estuarine water samples.
Evaluation of sucrose as an alternative to sodium chloride in the microtox® Assay: Comparison to fish and cladoceran tests with freshwater effluents
Authors: Ankley Gerald T. , Peterson Gregory S. , Amato Joseph R. , Jenson James J. 
Published: March 2010

Abstract
The toxicity of 44 freshwater effluents was evaluated using the fathead minnow (Pimephales promelas), a cladoceran (Ceriodaphnia dubia) and Microtox® (Photobacterium phosphoreum). The latter assay was conducted with both sodium chloride (NaCl) and sucrose for osmotic protection of the bacteria in an effort to determine whether the use of sucrose increased the sensitivity of Microtox to samples exhibiting toxicity to the fish and cladoceran species. Twenty-three of the effluents tested were toxic to fathead minnows and/or C. dubia; of these, Microtox was sensitive to 10 when tested in NaCl and seven when tested in sucrose. In one instance testing in sucrose predicted toxicity to the fish and cladoceran species when testing in NaCl did not. Single chemical tests demonstrated that Microtox sensitivity was greater to zinc chloride, nickel chloride and methanol when tested in sucrose as opposed to NaCl, about equal to copper sulfate and phenol in sucrose and NaCl, and was far greater to chlorine when tested in NaCl than in sucrose. These results, as well as data from Microtox assays with effluents containing known toxicants, suggest that the use of sucrose, in conjunction with NaCl, for osmotic adjustment in the assay could be helpful as part of a suite of tests for identifying general classes of compounds responsible for toxicity in freshwater effluents.
Dietary accumulation and sustained hepatic mixed function oxidase enzyme induction by 2,3,4,7,8-pentachlorodibenzofuran in rainbow trout
Authors: Muir Derek C. G. , Yarechewski Alvin L. , Metner Donald A. , Lockhart W. Lyle , Webster G. R. Barrie , Friesen Kenneth J. 
Published: March 2010

AbstractAccumulation of and hepatic monooxygenase induction by 2,3,4,7,8-pentachlorodibenzofuran (PnCDF) were studied in juvenile rainbow trout (Onchorhynchus mykiss) by feeding treated food for 31 d followed by a 180 d depuration period. Efficiency of assimilation was 44 and 41% at exposure concentrations of 9.0 and 0.82 ng g−1 PnCDF, respectively. Depuration of PnCDF followed first-order kinetics with half-lives (based on toluene extraction of 14C-radiolabel corrected for growth dilution) of 61 and 69 d at the low and high exposure concentrations, respectively. Monooxygenase enzyme induction measured by ethoxyresorufin-O-deethylase (EROD) activity in individual trout livers was 84- and four-fold higher after 31 d of exposure to 9.0 and 0.82 ng g−1, respectively, than in livers of unexposed fish. Sustained EROD activity at the high treatment concentrations was observed during the 180 d depuration phase. Ethoxyresorufin-O-deethylase activity declined at approximately half the rate of elimination of PnCDF. No significant differences between growth rates of treated and control fish were found.