bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the robustness of the fathead minnow, Pimephales promelas, larval survival and growth test, U.S. EPA method 1000.0
Authors: Pickering Quentin H. , Lazorchak James M. 
Published: March 2010

Abstract
An intralaboratory study was conducted to evaluate the robustness of the Fathead Minnow (Pimephales promelas) Larval Survival and Growth Test, Method 1000.0. Toxicity tests were conducted with the reference toxicants hexavalent chromium (Cr6+) and copper (Cu), and the data were statistically analyzed using hypothesis testing. Differences in age, size, feeding regimes, and water quality did not cause more than a twofold difference in 13 subchronic values (SCVs) for Cr6+. These tests involved side-by-side tests initiated with 1-, 4-, and 7-d larvae or initiated with 1-d larvae and two size groups of 4-d larvae fed differently. The mean SCV was 3,600 μg Cr6+/L, and the values ranged from 2,100 to 4,200 μg Cr6+/L. Eleven of these tests with a homogeneous variance gave an average minimum significant difference (MSD) of 14.3%. The no-observed-effect concentration (NOEC) for growth was always lower than the effect on survival. In the side-by-side tests with 1-, 4-, and 7-d larvae exposed in hard water the SCV was 35 μg Cu/L for each age group. Except for one test with Cu in soft water, the effects of Cr6+ and Cu on growth were more sensitive than the effect on survival. These toxicity tests along with some nontoxicant studies indicated that reasonable differences in methods parameters did not cause any changes greater than a factor or two in analytical results despite the “noise” of biological variability.
The association of DNA damage to concentrations of mercury and radiocesium in largemouth bass
Authors: Sugg Derrick W , Chesser Ronald K , Brooks Janet A , Grasman Brian T 
Published: March 2010

AbstractLargemouth bass from five lakes were examined to determine levels of contamination by mercury and radiocesium and amounts of DNA damage Concentrations of these toxicants and an index of body condition were regressed against over all DNA damage and DNA damage in individual tissues (liver, gills, and red blood cells) as indicated by the alkaline unwinding method Sample sites showed considerable heterogeneity in concentrations of mercury and radiocesium, as well as numbers of DNA strand breaks Generally, increased concentrations of toxicants were related to increased DNA damage Tissues may have responded to contaminants in different manners, red blood cells generally showed the greatest DNA damage while liver tissue showed the least Although body condition was related to DNA damage, it is unclear whether it has a direct effect or whether it is a correlated response to contamination by mercury and radiocesium The potential for repair of DNA strand breaks and cell turnover rates may play an important role in determining the ultimate amount of DNA damage in contaminated organisms
Inhibition of renal xenobiotic excretion by tetrachloroguaiacol: Mechanism and possible consequences
Authors: Oikari A. O. J. , Walden R. , Pritchard J. B. 
Published: March 2010

AbstractThe weak acid tetrachloroguaiacol (teCG; pKa 6.0) is the major chlorinated phenol produced during chlorine bleaching of wood pulp. Upon its release into the environment, it is persistent and markedly bioaccumulated (100- to 1,000-fold). Within the organism (pH ∼ 7.4), it should be &gt;95% ionized, making it a likely inhibitor of renal organic anion transport. Its effects on both passive membrane permeability and mediated transport processes were determined in basolateral (BLM) and luminal membrane (BBM) vesicles isolated from the rat kidney cortex. Vesicular solute uptake was measured by the rapid filtration technique at pH 7.5. Passive membrane permeability (assessed by mannitol uptake) was altered only at very high concentrations of teCG (≥ 1,000 μM). In contrast, transport of the model organic anion p-aminohippurate (PAH) by BLM vesicles was significantly inhibited by as little as 5 μM (1.3 mg/L) teCG and totally abolished by 200 μM. Inhibition was competitive (K1 = 31.3 μM). Decreasing assay pH diminished inhibition of the PAH uptake, reflecting the reduced concentration of ionized teCG. Other membrane effects were seen at higher teCG concentrations (&gt; 100 μM). The BLM sodium/glutarate cotransport was modestly, but significantly, stimulated by 100 to 500 μM teCG, whereas BBM sodium/glucose cotransport was inhibited by similar teCG concentrations. Thus, teCG has multiple effects on renal membrane function. However, at environmental levels (0.1 to 30 μM in plasma), its principal membrane effects would be related to changes in organic anion secretion.
Rapid mineralization of the herbicide atrazine in alluvial sediments and enrichment cultures
Authors: Topp Edward , Gutzman Donald W. , Millette Jacques , Gamble Donald S. , Bourgoin Bernard 
Published: March 2010

Abstract
The fate of atrazine in sediment sampled from two agricultural watersheds in the Great Lakes basin of southern Ontario was studied in laboratory flask incubations of sediment slurry and enrichment cultures. Atrazine at an initial concentration of 10 mg/L disappeared within 15 d in sediment slurries incubated aerobically at 30°C. Because atrazine concentrations were stable in similarly incubated autoclaved slurry and the lag preceding atrazine degradation was abolished by repeated atrazine additions, it was concluded that the herbicide was biodegraded. Rapid atrazine degradation was found in concentrated suspended particulates and surface (0 to 10 cm) sediments, but not in sediments taken from a depth of 20 cm. Atrazine was not degraded under anaerobic or denitrifying conditions. Sediment and enrichment cultures converted [U-ring-14C]-labeled atrazine to hydrophilic metabolites, tentatively identified as cyanuric acid and urea, and then to carbon dioxide.
Behavior of [14C]-4-nitrophenol and [14C]-3,4-dichloroaniline in laboratory sediment-water systems: Part 2. Desorption experiments and identification of sorptive fraction
Authors: Heim Kerstin , Schuphan Ingolf , Schmidt Burkhard 
Published: March 2010

AbstractBoth [14C]-4-nitrophenol (4-NP) and [14C]-3,4-dichloroaniline (3,4-DCA) were applied to laboratory sediment-water systems; these were a sandy sediment (SED-M), and a sediment with high clay/silt and organic carbon content (SED-J). After sorption periods of 2 d (assay I) and 28 d (assay II) the water phases were replaced by fresh sample water. About 20/10% (3.9/3.9% of total applied 4-NP in SED-M/SED-J) and 40/15% (8.5/6.2%; 3,4-DCA) of the sediment-associated radioactivity were initially (1 d of incubation) desorbed in assay I. The corresponding data of assay II amounted to 2/1% (0.9/0.7%; 4-NP) and 3/2% (1.7/1.4%; 3,4-DCA). No parent compounds were detected in the fresh-water phases. The radioactivity released in assay I was readsorbed to the respective sediment. Remobilization distinctly reflected the preceding sorption process, and that regarding sediment properties and chemical features of 3,4-DCA and 4-NP. Fractionation of the nonextractable residues of 3,4-DCA in SED-J revealed that the xenobiotic was mainly attached to the insoluble humin fraction (55.8/53.8% after 7/28 d of incubation). Only minor amounts were associated with fulvic (14.3/12.7%) and humic acids (5.3/6.1%). Experiments using a clay fraction of SED-J (&lt; 0.063 μm; SED-J-C) and bentonite (CM) demonstrated that 3,4-DCA was primarily bound to the organic matter of SED-J-C. Concerning sorption of 3,4-DCA, both SED-J and SED-J-C behaved very alike; in contrast, CM showed a strikingly different pattern. Regarding “outdoor” situations, it may be concluded that 4-NP is not translocated very far from the site of contamination, whereas 3,4-DCA shows considerable mobility.
A novel detection scheme for herbicidal residues
Authors: Hannan Patrick J. 
Published: March 2010

Abstract
It is relatively simple to determine the growth rate of a microorganism culture, minute-by-minute, by monitoring the CO2 content of an air stream that has passed through the culture at a constant rate. Any change in the growth rate caused by the addition of a toxicant is readily detectable. This is the basis of a procedure for detecting sulfonylurea herbicides on vegetation. A freshwater alga (Chlorella pyrenoidosa sorokiniana) and baker's yeast (Saccharomyces cerevisiae) were the test organisms evaluated in this study. The alga was the more sensitive to sulfonylureas, and the effect of 0.01 μg of a sulfonylurea that had been simply leached from an apple leaf was evident in 15 min. Triazine herbicides inhibit the Chlorella even more rapidly than the sulfonylureas.
Integrity of a cellulose granular pesticide carrier in house sparrow gizzards
Authors: Best Louis B. , Gionfriddo James P. 
Published: March 2010

Abstract
This study evaluated the integrity of a cellulose-complex granular pesticide carrier in gizzards of house sparrows (Passer domesticus). Within 1 h after dosing, nearly all cellulose-complex granules had disappeared from the birds' gizzards. Cellulose granules remained intact for 14 d, however, in a hydrochloric acid solution without the mechanical grinding of the gizzard.
Alteration of the homing-flight in the honey beeApis melliferaL. Exposed to sublethal dose of deltamethrin
Authors: van dame Rémy , Meled Maggy , Colin Marc-Edouard , Belzunces Luc P. 
Published: March 2010

AbstractForaging activity of bees is currently disturbed by treatments with pyrethroid agrochemicals. To discover eventual troubles of spatial orientation of the foragers, we exposed bees to sublethal doses of deltamethrin sufficiently low to avoid motor incoordination or muscular troubles. In an insect-proof tunnel, bees were trained to forage at a feeder 8 m from their nucleus. When temperature and global radiance conditions were optimal, some foragers were caught, exposed to a deltamethrin dose 27 times lower than its LD50, and released after 20 min of recovering. Among the contaminated bees, 54% took flight toward the sun and 81% did not come back to their nest within 30 s (which is 3 times longer than the mean time of control bees). Because pyrethroids are known to disturb learning and memory, we cannot conclude if this disorientation is due either to a trouble of information storage (wrong spatial perception or phototropism increase), or to a trouble of information retrieval (bad comparison of actual and memorized patterns). Routine chemical analysis of exposed bees does not detect residues of deltamethrin 3 h after bee sublethal exposure, although bees evidenced alteration in the flight.
Development of toxic equivalency factors for PCB congeners and the assessment of TCDD and PCB mixtures in rainbow trout
Authors: Newsted John L. , Jones Paul D. , Giesy John P. , Crawford Robert A. , Ankley Gerald T. , Tillitt Donald E. , Gooch Jay W. , Denison Michael S. 
Published: March 2010

Abstract
This study was undertaken to evaluate the relationship between mammalian and piscine 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factors (TEFs) for PCBs, based on induction of CYP1A enzyme activity, catalytic protein, and mRNA. Rainbow trout administered a single i.p. injection of TCDD had an average (±SD) ED50 of 0.91 ± 0.14 μg TCDD/kg for induction of ethoxyresorufin O-deethylase (EROD) activity. Ortho-substituted PCB congeners 2,3,3′,4,4′-pentachlorobiphenyl (PCB 105), 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118), 2,3,3′4,4′5-hexachlorobiphenyl (PCB !56), and 2,2′3,4,4′,5-hexachlorobiphenyl (PCB 138) did not induce CYP1A activity in rainbow trout. Only three non-ortho-substituted PCBs, i.e., 3,3′4,4′-tetrachlorobiphenyl (PCB 77), 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126), and 3,3′4,4′5,5′-hexachlorobiphenyl (PCB 169) induced CYP1A enzyme activity, protein, and mRNA. The ED50s for induction of EROD activity were calculated as 134, 5.82, and 93.7 μg/kg for PCB 77, PCB 126, and PCB 169, respectively. The TCDD-TEFs based on EROD activity were 0.0006, 0.0014, and 0.0003 for PCB 77, PCB 126, and PCB 169, respectively. Binary mixtures of TCDD and three PCBs were also evaluated. Based on EROD activity and CYP1A protein, mixtures of TCDD and PCB 77 were slightly greater than additive. Mixtures of TCDD-PCB 156 and TCDD-PCB 126 were slightly less than additive. Results from these studies indicate that mammal-derived TEFs will underestimate the potency of planar chlorinated hydrocarbon mixtures to induce the CYP1A catalytic activity in rainbow trout. Also, while interactions among PCB congeners and TCDD were somewhat equivocal, they did not greatly differ from predicted additive responses.
Effects of carbaryl grasshopper control on nesting killdeer in North Dakota
Authors: Fair Jeanne M. , Kennedy Patricia L. , McEwen Lowell C. 
Published: March 2010

Abstract
There is currently special concern for the effects of range grasshopper control on insectivorous grassland birds, such as upland shorebirds. The direct and indirect effects on killdeer (Charadrius vociferus) of carbaryl applications for grasshopper control were investigated in North Dakota in 1992. Specimens were collected from two rangeland sites aerially sprayed with 1.44 and 1.12 kg/ha of Sevin-4-Oil (0.56 and 0.45 kg/ha carbaryl active ingredient, respectively) and two untreated areas. Potential exposure to carbaryl, estimated from pesticide residue concentrations of whole-body and gizzard contents, was highest 2 d after treatment and then decreased over time. Whole-body carbaryl residues averaged significantly higher (p &lt; 0.05) in specimens from sprayed areas, particularly from sites where the higher carbaryl application was used. There was no difference in the mean brain AChE activity and whole-body lipid content of killdeer from treated and untreated areas. The relative abundance of arthropods (principal prey of killdeer) was also estimated on the treatment area. As expected, grasshopper densities declined significantly posttreatment but the spray caused a temporary increase in the availability of affected grasshoppers. The two application rates caused similar reductions in grasshopper numbers. Killdeer did not exhibit a functional response of a prey switch as a result of the spray, but they did demonstrate an increased arthropod capture rate for a short period (8 d) after treatment. Although exposure was documented on the higher application rate area, this exposure was apparently not high enough to cause an impact on the parameters we measured in this study. These results support the conclusions of other studies that carbaryl, applied at the rate of 1.12 kg/ha, has little impact on birds and is equally as effective in reducing grasshopper numbers as the higher application rate.
An approach to quantifying spatial components of exposure for ecological risk assessment
Authors: Clifford Philip A. , Ludwig David F. , Barchers Daniel E. , Klingensmith J. Scott , Graham Richard V. , Sielken Robert L. , Banton Marcy I. 
Published: March 2010

Abstract
Estimating ecological risks associated with contaminants in the environment requires accurate characterization of the exposure of organisms to potentially toxic materials. Because organisms integrate contaminant exposure over space and time, estimating exposure concentrations reflective of actual exposures is a complex task. Quantification of spatial components of environmental exposure can utilize computerized Geographic Information Systems (GIS) as a central tool. The GIS was used to evaluate ecological risks to terrestrial receptors at a National Priorities List (NPL) site where dieldrin was one of the contaminants. The GIS was applied directly to estimating spatially weighted exposure concentrations within organisms' foraging, or exposure ranges. Moreover, GIS was also used for comparing exposure concentrations to “benchmark” concentrations and subsequent presentation of the results in a three-dimensional “risk surface” format. The three-dimensional risk surfaces were then superimposed on site-specific maps to serve as effective visual representations of site-specific quantified ecological risks and, as such, provide an effective risk-management decision-making tool. As an integral part of this approach, GIS serves as an interactive tool for assessing the effectiveness of proposed remedial alternatives by facilitating evaluation of effects of various remediation scenarios. This capability can be used to optimize remedial costs, benefits, and impacts.
A comparison of standard acute toxicity tests with rapid-screening toxicity tests
Authors: Toussaint Margaret W. , Shedd Tommy R. , van der Schalie William H. , Leather Gerald R. 
Published: March 2010

AbstractThis study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus calyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photobacterium phosphoreum–Microtoxr̀ test, and a mixture of bacterial species–the Polytoxr̀ test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriodaphnia dubia), green algae (Selenastrum capricornutum), fathead minnows (Pimephales promelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex “real-world” environmental samples is recommended.
A proposal for the definition of resource equivalency factors for use in product life-cycle assessment
Authors: Guinée Jeroen B. , Heijungs Reinout 
Published: March 2010

Abstract
Environmental life-cycle assessment (LCA) of products has been the focus of growing attention in the last few years. The methodological framework has been developed rapidly, and a provisional “Code of Practice” has been drawn up by an international group of experts. One of the elements of LCA is impact assessment, which includes a characterization step in which the contributions of resource extraction and polluting emissions to impact categories such as resource depletion, global warming, and acidification are quantified and aggregated as far as possible. This can be achieved by multiplying extractions and emissions by a so-called equivalency factor and aggregating the results in one or more effect score(s) per impact category. In this report a proposal is developed for equivalency factors indicating the relative depletion of a resource per unit extracted. It is proposed to measure depletion by physical data on reserves and production and regeneration rates, and to distinguish between abiotic and biotic resources. Equations are developed to calculate equivalency factors for these two categories of resources, resulting in so-called abiotic depletion potentials (ADP) and biotic depletion potentials (BDP). The application of these ADPs and BDPs in LCA is illustrated.
Kinetics of phthalate ester biodegradation by Chlorella pyrenoidosa
Authors: Yan Hai , Ye Changming , Yin Chengqing 
Published: March 2010

Abstract
Experimental results show that Chlorella pyrenoidosa has an ability to accumulate and biodegrade phthalate esters. Bioconcentration factors of dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBF) reached their maxima of 162 at 24 h, 205 at 12 h, and 4,077 at 12 h. The average biodegradation rates of DMP, DEP, and DBF per day were found to be 13.4 mg/L, 7.3 mg/L, and 2.1 mg/L, respectively. Based on the experimental data, a second-order kinetic equation was formulated as - dC/dt = KNr, with a factor r indicating the rate of algal growth. Calculation of this equation fits well with the observed data, and the standard deviations between calculated and observed values were 1.72 mg/L, 1.80 mg/L, and 0.26 mg/L for DMP, DEP, and DBF, respectively.
Dehalogenation of chlorinated dioxins by an anaerobic microbial consortium from sediment
Authors: Beurskens Jacobus E.M. , De Wolf Johan , Toussaint Erel , van der Steen Jan M.D. , Slot Pieter C. , Commandeur Laetitia C.M. , Parsons John R. 
Published: March 2010

Abstract
Anaerobic microorganisms enriched from Rhine River sediments are able to remove chlorine substituents from poly-chlorinated dibenzo-p-dioxines (PCDDs). A model PCDD, 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4–TeCDD) was reduc-tively dechlorinated to both 1,2,3–and l,2,4–trichlorodibenzo-/&gt;-dioxins (1,2,3–and 1,2,4–TrCDD). These compounds were further dechlorinated to 1,3–and 2,3–dichlorodibenzo-p-dioxins and traces of 2–monochlorodibenzo-p-dioxin. This is the first report in the literature of the anaerobic microbial dechlorination of PCDDs. The same enrichment culture was previously found to deSchlorinate chlorinated benzenes (CBs) and polychlorinated biphenyls (PCBs). An anaerobic culture able to remove aryl chlorines from three classes of compounds has not been reported before. The rate at which the culture dechlorinates 1,2,3,4–TeCDD (t1/2 = 15.5 d) was between those observed for CBs and PCBs. This study shows that reductive dechlorination may have an effect on PCDDs in sediments, as has been demonstrated for CBs and PCBs. The formation of metabolites with a conserved 2,3-substitution pattern from 1,2,3,4–TeCDD indicates that dechlorination of highly chlorinated dibenzo-p-dioxins may result in metabolites that are potentially more toxic than the parent compounds.
Physiological and biochemical perturbations inDaphnia magnafollowing exposure to the model environmental estrogen diethylstilbestrol
Authors: Baldwin William S. , Milam David L. , Leblanc Gerald A. 
Published: March 2010

AbstractThe estrogenic properties of many environmental contaminants, such as DDE and PCBs, have been associated with reproductive failure in a variety of vertebrate species. While estrogens have been measured in many invertebrate species, the function of this hormone in invertebrates is controversial. The objective of the present study was to identify possible physiological and biochemical target sites for the estrogenic effects of some xenobiotics on the freshwater crustacean Daphnia magna using the model environmental estrogen diethylstilbestrol (DES). Chronic exposure of daphnids to 0.50 mg/L DBS reduced molting frequency among first-generation juveniles and decreased fecundity of second-generation daphnids. Adult first-generation daphnids chronically exposed to DES, as well as adult daphnids acutely exposed to DES for only 48 h, were examined for steroid hormone metabolic capabilities using testosterone as the model steroid. The rate of elimination of two major hydroxylated metabolites of testosterone was significantly reduced, and elimination of glucose conjugates of testosterone was significantly elevated from exposure to 0.50 mg/L DES. These results demonstrate that multigeneration exposure of daphnids to DES results in reduced fecundity and altered steroid metabolic capabilities. Thus, some arthropods, like vertebrates, are sensitive to the effects of endocrine-disrupting chemicals.