bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of five alkyl-aryl phosphate ester chemicals to four species of freshwater fish
Authors: Cleveland Laverne , Mayer Foster L. , Buckler Denny R. , Palawski Donald U. 
Published: March 2010

Abstract
The toxicities of five phosphate ester compounds — Fyrquel GT, Kronitex 200, Phosflex 31P, Pydraul 50E and Santicizer 148—were evaluated in acute toxicity tests with rainbow trout (Salmo gairdneri), fathead minnows (Pimephales promelas), channel catfish (Ictalurus punctatus) and bluegills (Lepomis macrochirus) and in 90-d partial life-cycle tests with fathead minnows. Nominal exposure concentrations were 0, 0.06, 0.12, 0.25, 0.5 and 1.0 mg/L in the partial life-cycle tests with Fyrquel GT, Kronitex 200, Phosflex 31P and Pydraul 50E, and 0, 0.05, 0.09, 0.19, 0.38 and 0.75 mg/L in the test with Santicizer 148.
The 96-h LC50 values for rainbow trout, fathead minnows, channel catfish and bluegills exposed to the five phosphate esters ranged from less than 0.3 to greater than 72 mg/L. The LC50 values may be directly related to the percentage of triphenyl phosphate contained in each of the compounds. The phosphate esters generally showed similar chronic toxicities to fathead minnows, and adverse toxic effects occurred at nominal exposure concentrations of 0.38 to 1.0 mg/L. Comparison of available environmental concentration data for phosphate esters with the effect concentrations obtained for fish in the present study indicated that phosphate ester compounds may not now pose a threat to fish populations.
Comparison of pesticide root zone model predictions with observed concentrations for the tobacco pesticide metalaxyl in unsaturated zone soils
Authors: Carsel Robert F. , Nixon Will B. , Ballantlne Larry G. 
Published: March 2010

Abstract
The pesticide root zone model (PRZM) was developed to evaluate pesticide leaching threats to ground water for different crops under varying climatic conditions, soil characteristics and cropping practices. In this study, PRZM was evaluated to establish its predictive capability by comparing observed metalaxyl concentration profiles with predicted concentration profiles using field-averaged pesticide data and best estimates for several hydrologic characteristics and pesticide transport properties at field sites in Florida and Maryland. Coefficients of determination for the Florida site at 26, 55 and 85 d after application of 0.33, 0.90 and 0.95, respectively, were obtained when field observations were regressed against model predictions. An overall coefficient of determination for the Maryland site of 0.75 was determined for 14 samplings after metalaxyl application.
Pesticide transformation in the Florida soil was best described by a first-order model. A first-order degradation rate in soil of 0.014 d−1 was estimated. Pesticide transformation in the Maryland soil was best described by a phased first-order model. A phase determination point that occurred 30 d after metalaxyl application was used to estimate soil degradation rates. Differences were attributed to the timing of rainfall events and soil infiltration characteristics. Estimated phased first-order degradation rates in soil for the Maryland site were 0.046 and 0.0045 d−1 before and after the phase determination point.
Evaluation of PRZM, using best estimates for transport and transformation properties of metalaxyl and limited calibration for water balance, suggests that the model effectively simulates the important processes operating on the pesticide.
Validation trial of predictive fate models using an aquatic herbicide (endothall)
Authors: Reinert K. H. , Rodgers J. H. 
Published: March 2010

Abstract
Environmental risk assessment of pesticides in aquatic environments requires predictions of their persistence and compartmentalization. A strategy for developing confidence in predictive fate models, such as the Exposure Analysis Modeling System (EXAMS) and the Simplified Lake and Stream Analysis model (SLSA), is to test the models using carefully chosen chemicals in semi-controlled and field situations. For example, endothall, a relatively water-soluble aquatic herbicide, essentially has a sole fate process, biotransformation. This dicarboxylic acid was used to test the predictive capabilities of EXAMS and SLSA and to identify sources of variance in those predictions. The models were parameterized using laboratory, experimental pool and field measurements. Persistence and compartmentalization of endothall in the water, sediments and aquatic plants (Eurasian watermilfoil—Myriophyllum spicatum L.) contained in experimental pools were measured using gas chromatography. Both EXAMS and SLSA predicted aqueous compartment half-lives ranging from 7.3 to 7.8 d, whereas an aqueous half-life of 4 d was observed in the experimental pools. Endothall was introduced to areas within Pat Mayse Lake, a 2,400-ha reservoir in north central Texas, as part of an aquatic plant management program for M. spicatum. Concentrations of endothall were below detection limits (0.002 mg L−1 water, 0.01 mg kg−1 sediment) in 2 to 3 d and in 4 d in the water and sediment compartments, respectively. EXAMS and SLSA predicted half-lives ranging from 3 to 6 d in the water column. Observed aqueous half-lives ranged from 0.1 to 0.23 d. Horizontal dispersion and dilution contributed significantly to the dissipation of endothall at these sites. Predicted concentrations of endothall in sediment were similar to the measured concentrations. This study is one validation trial of EXAMS and SLSA in which the models were not considered validated.
Evaluation of the archiannelid Dinophilus gyrociliatus for use in short-term life-cycle toxicity tests
Authors: Carr Robert Scott , Curran Mark D. , Mazurkiewicz Michael 
Published: March 2010

Abstract
The use of the archiannelid Dinophilus gyrociliatus O. Schmidt in short-term (7 to 10 d) life-cycle tests with reference toxicants and industrial effluents was evaluated. Culture techniques and test protocols were developed and evaluated. The life history of this archiannelid was also studied and is described. Because this species has a very short life cycle (10 d from juvenile to juvenile at 20°C and 30%+ salinity), reproductive information can be obtained during a short-term test. The results of tests with industrial effluents and reference toxicants indicate that this species is suitable for toxicity testing and appears to be quite sensitive to the industrial effluents tested in this study. The animals are easily cultured and the testing procedure requires very little time for setup and maintenance (1 to 2 h/d). It has been determined that reproductive information can be obtained during a 7-d test that starts with newly emerged juveniles.
Relation of survival to other endpoints in chronic toxicity tests with fish
Authors: Mayer Foster L. , Mayer Kathleen S. , Ellersieck Mark R. 
Published: March 2010

Abstract
Hazard assessments of chemicals in aquatic organisms often include chronic toxicity testing. The evaluation of exposure duration and of the life stages tested according to standard test methods has led to the development of shorter chronic toxicity tests. A similar evaluation of biological endpoints (i.e., survival, growth and reproduction) could result in tests that are more economical. We analyzed endpoints for 28 chemicals and seven fish species in 34 chronic toxicity studies. When all endpoints were compared, survival was equal to or more sensitive than all other endpoints 56 to 69% of the time. Individual endpoints were more sensitive than survival 19 to 61% of the time, except for reproduction, which was always more sensitive (although there were few observations). The no observed effect concentration (NOEC) for growth could be predicted from the NOEC for survival by using interendpoint correlations (r = 0.949 to 0.974). Ratios of NOECs for survival to those for all other endpoints examined were 5 or less in 93 to 96% of the comparisons (specific endpoint comparisons ranged from 80 to 100%).
The determination of the survival endpoint requires less time and money than does the determination of most other endpoints, and it appears adequate for hazard assessments in the initial stage of estimating chronic toxicity. However, a factor of at least 0.2 should be applied to the estimated no-effect concentrations for survival to include other potential biologically significant effects at least 95% of the time. The factor of 0.2 is based on frequency analyses that resulted in the NOECs for survival being 5 times or less than the NOECs for most other endpoints about 95% of the time. Univariate analyses, however, indicated a range of 0.13 to 0.22 for the factor. A thorough evaluation of other published studies that contain endpoints other then survival should be conducted to define the appropriate factor more accurately.
Simultaneous evaluation of the acute effects of chemicals on seven aquatic species
Authors: Ewell William S. , Gorsuch Joseph W. , Kringle Robert O. , Robillard Kenneth A. , Spiegel Richard C. 
Published: March 2010

Abstract
A cost-effective testing procedure is described that measures the acute aquatic effects of a single test chemical on seven aquatic species simultaneously: Asellus intermedius (pillbug), Daphnia magna (water flea), Dugesia tigrina (flatworm), Gammarus fasciatus (sideswimmer), Helisoma trivolvis (snail), Lumbriculus variegatus (segmented worm) and Pimephales promelas (fathead minnow). These species were chosen because of their ecological importance, diversity and amenability to laboratory culturing. Twenty-seven commercial inorganic and organic chemicals were tested using the simultaneous exposure procedure. The 96-h LC50 values were derived for each species and the results compared with literature values. The reproducibility of the results achieved using this testing procedure was shown to be very good. The results compare favorably with 96-h LC50 values from single-species tests.
The susceptibility of test animals as a function of species and chemical compound was evaluated. Water fleas were found to be as susceptible as, or more so than, the other aquatic organisms for all compounds tested. The relative sensitivities of the other test species were found to be highly chemical dependent.
Comparative toxicology of phenolic compounds using root elongation method
Authors: Wang Wuncheng C. 
Published: March 2010

Abstract
The U.S. Environmental Protection Agency and the Organization for Economic Cooperation and Development both recommend cucumber, lettuce, radish, red clover and wheat as plant species for terrestrial toxicity tests. In Illinois, millet is common in the Illinois River Valley and toxicity testing using this plant species has been reported previously. The objective of this study was to compare the toxicities of several phenolic compounds to cucumber, lettuce and millet seeds concurrently. Phenol, 2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol were tested.
Millet seeds were shown to be superior over cucumber and lettuce seeds; they exhibited regular and predictable toxic responses to all four compounds. Millet seeds, in addition, were the most sensitive. Excellent results were obtained for the structure-toxicity relationships between millet EC50s and the molecular weights of the phenols (R = 0.999), and between millet EC50s and n-octanol/water partition coefficients (R = 0.999). It is recommended, consequently, that millet be included in level 1 biological tests.
Evaluation of proadifen HCL as a synergist for temporary immobilization and toxicity of eight chemicals in coturnix quail
Authors: Cunningham D. J. , Otis D. L. , Schafer E. W. 
Published: March 2010

AbstractProadifen HCl (SKF-525A), a hepatic microsomal enzyme inhibitor, was evaluated as a synergist for eight chemicals that produced temporary immobilization (TI) at sublethal levels in birds. Probit analysis showed that Proadifen HCl administered orally and concurrently at 100 mg/kg to quail (Coturnix coturnix japonica) with four of the test chemicals (alpha-chloralose, chlordiaz-epoxide, nicotine sulfate and phencyclidine) significantly lowered (p = 0.05) the estimated median lethal (LD50) and/or temporary immobilization response (TI50). Proadifen HCl reduced the LD50 dose for alpha-chloralose 1.56-fold and the TI50 2.03-fold; the TI50 dose for chlordiazepoxide HCl 2.47-fold; the LD50 dose for nicotine sulfate 4.10-fold and the TI50 2.98-fold; and the LD50 dose for phencyclidine HCl 2.35-fold and the TI50 27.5-fold. The synergism exhibited by Proadifen HCl with metomidate and tribromoethanol was less or negative. The LD50 of metomidate was reduced 1.96-fold, but the TI50 was not affected. The LD50 of tribromoethanol was increased 1.15-fold, but the TI50 was reduced by a factor of 1.48. There was no synergism between Proadifen HCl and methiocarb or pentobarbital. These data show that the LD50 and/or TI50 of temporary immobilizing agents for birds can be affected by the use of a synergist such as Proadifen HCl, and indicate that synergism between bird control chemicals or pesticides and drugs could be used to improve efficacy, lower application rates and reduce environmental contamination.
Exposure of forestry ground workers to 2,4-D, picloram and dichlorprop
Authors: Lavy T. L. , Mattice J. D. , Marx D. B. , Norris L. A. 
Published: March 2010

Abstract
Urine samples from 80 forest workers applying 2,4-D [(2,4-dichlorophenoxy)acetic acid] plus dichlorprop [(±)-2-(2,4-dichlorophenoxy)propanoic acid] or picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) by ground techniques were monitored to determine the dose of chemical absorbed. Four crews of 20 workers each were studied to compare the exposures during application by backpack, injection bar, Hypohatchet or a hack-and-squirt method. Total urine output was analyzed to compare the absorbed dose to each worker under two operational modes. In the first, designated T-1, the workers wore their usual clothing and followed the work habits they ordinarily used on the job. In the second mode, designated T-2 and conducted 6 d after the first, workers were given new leather gloves and boots and asked to take all feasible precautions to prevent herbicide exposure and to wash immediately if they come into contact with the chemical.
For all application methods except that with backpacks, the T-2 treatment decreased the absorbed dose. During both T-1 and T-2 the clothing of backpack sprayers often became saturated with spray, dew or perspiration, and these workers received a higher absorbed dose of 2,4-D (0.04–0.24 mg/kg body weight) than did workers in other crews. The absorbed dose of dichlorprop ranged from undetectable to 0.18 mg/kg. Hypohatchet workers received a greater dose than did injection bar or hack-and-squirt workers. The absorbed dose of picloram ranged from undetectable to 0.02 mg/kg. If equal dermal penetration of 2,4-D and picloram is assumed, this represents much less dermal absorption than would have been predicted from the relative amounts of 2,4-D and picloram in Tordon 101-Rr̀.
Effects of chronic exposure to acidified water on chemoreception of feeding stimuli in fathead minnows (Pimephales promelas): Mechanisms and ecological implications
Authors: Lemly A. Dennis , Smith R. J. F. 
Published: March 2010

Abstract
A computer-automated behavioral assay was used to assess the effects of reduced ambient pH on the response of fathead minnows to chemical feeding stimuli. The testing system quantified eight behavioral parameters based on the activity level of individual fish before and after exposure to a single-pulse dose of a feeding stimulus—a tissue culture medium (1 ml; Eagle minimum essential medium with Earl's salts and L-glutamine) — injected into the water circulation. Twentyfive adult minnows were tested after exposure to one of five pH levels: 8.0 (control), 7.0, 6.5, 6.0 and 5.5. Complete elimination of the feeding response occurred at pH = 6 and lower; responses at higher pH levels were not statistically different from those in the controls. Differences in water hardness (&lt;10 mg/L CaCO3 versus &gt; 160 mg/L CaCO3) and duration of exposure (72 h versus 30 d) had no influence on the pattern or degree of the pH effects. Scanning electron microscopy revealed no pathological or gross morphological correlates of the behavioral changes. To test for possible recovery, minnows that did not respond at pH = 6 were placed in water of control pH (8.0) for 24 h and then tested again; a statistically significant response to the feeding stimulus was restored. These results indicate that acute and chronic sublethal levels of acidification caused a reversible impairment of chemoreception and that the impairment can occur at a relatively high pH. The toxic effect probably involves mechanical and chemical inhibition of receptor cells in the olfactory and gustatory epithelia rather than actual destruction of chemosensory tissue. In nature, reduction of pH to approximately 6.0 could impair feeding behavior and reduce food intake, fecundity and long-term survival of fathead minnow populations. Our results correspond well with environmental studies that show that fathead minnows are eliminated from natural waters when pH levels reach 5.8 to 6.0.
Toxic effects of selected bleached kraft mill effluent constituents on the sea urchin sperm cell
Authors: Cherr Gary N. , Shenker Jonathan M. , Lundmark Cathy , Turner Kenneth O. 
Published: March 2010

Abstract
The toxicities of chemicals found in bleached kraft pulp mill effluent were assessed using a sea urchin sperm toxicity test. Sperm of the purple sea urchin, Strongylocentrotus purpuratus, were preincubated with 12 individual compounds, including resin acids, unsaturated fatty acids, their chlorinated derivatives and chlorinated guaiacols. Sperm were then coincubated with eggs and inhibition of fertilization and the effects on sperm motility were assessed. Resin acids, which are highly toxic to juvenile salmonids in freshwater, were less toxic in seawater (EC50s ranging from 2 to more than 20 mg/L). Unsaturated linoleic and linolenic fatty acids inhibited fertilization at lower concentrations (EC50s of 0.28 to 1.07 mg/L) than resin acids, although they are less toxic than resin acids to freshwater fishes. Oleic acid was not significantly toxic up to 75 mg/L. Chlorinated derivatives showed increasing toxicity with increasing chlorination, and chlorinated resin acids were more toxic than their unchlorinated parent compound. Dichlorostearic acid was the most toxic compound tested, with an EC50 of 0.057 mg/L. All compounds except fatty acids inhibited sperm motility.
These results indicate that some of the major constituents of pulp mill effluent exhibit very different levels of toxicity in seawater using a sea urchin sperm cell toxicity test as compared to freshwater bioassays using juvenile salmonids. In addition, mechanisms of action on the sperm appear to differ among the compounds. Accurate quantification of the compounds in effluent as well as the potential effect of the effluent on other marine organisms remains to be determined.
Detection of cadmium-binding proteins in fish chronically exposed to heavy metals
Authors: Benson William H. , Birge Wesley J. 
Published: March 2010

Abstract
Studies were undertaken to determine the presence of cadmium-binding proteins in fish from a metal-contaminated flyash disposal pond and relatively uncontaminated hatchery ponds. Fractionation of gill cytosolic proteins by gel filtration indicated three classes of cadmium-binding proteins. While no cadmium was detected in the metallothionein (MT)-like fraction of the hatchery fish, 1% of the cytosolic cadmium was detected in this fraction for ash pond fish. Cadmium concentrations in the flyash pond were previously reported as ranging from 0.30 to 0.98 μg/L. This level of exposure may be insufficient to induce significant biosynthesis of MT-like proteins.
Incorporating Daphnia magna into the seven-day Ceriodaphnia effluent toxicity test method
Authors: Knight John T. , Waller William T. 
Published: March 2010

Abstract
The experiments reported here describe the incorporation of Daphnia magna into the 7-d Ceriodaphnia toxicity test procedure of Mount and Norberg [1]. The addition of D. magna to the procedure increased the number of parameters on which decisions regarding sublethal effects could be determined without significantly increasing the workload. In addition to the survival and productivity measures of the Mount and Norberg procedure, length and weight of Ceriodaphnia dubia adults and D. magna adults and neonates were evaluated.
Methods for the culture and testing of both organisms using Selenastrum capricornutum Printz as the food source were described. An analysis of algal caloric content, chlorophyll a, cell number, mean cell volume, dry weight, number of bacteria, storage time, and time since the algae were “cleaned” was made to determine the characteristics of the feeding suspensions which most influenced the growth and productivity of the cladocerans.
Comparative toxicity and speciation of two hexavalent chromium salts in acute toxicity tests
Authors: Jop Krzysztof M. , Parkerton Thomas F. , Rodgers John H. , Dickson Kenneth L. , Dorn Philip B. 
Published: March 2010

Abstract
The comparative acute toxicity of potassium chromate and dichromate salts to six aquatic species including both freshwater and marine forms was investigated. A thermodynamic equilibrium model was developed to aid in interpreting toxicity data with respect to hexavalent chromium speciation. Although parallel acute toxicity tests conducted with both salts yielded similar LC50 values, toxicity differences tended to become more pronounced as the sensitivity of the test species to the chemical decreased. Observed changes in pH and predicted changes in chromium speciation that occurred between the two salts in tests with less sensitive species were postulated to explain these findings. The implication of the aqueous chromium species to the relative toxicity of the hexavalent chromium are discussed. If hexavalent chromium is widely adopted as a standard reference toxicant for aquatic toxicity testing then the chromate salt should be used since it does not appreciably alter the initial pH of the dilution water and subsequent speciation to the extent that would be expected if the dichromate salt was employed. Standardization of the source of hexavalent chromium used in reference tests will facilitate intralaboratory comparison of toxicity data.
Reductive dechlorination of 4-chlororesorcinol by anaerobic microorganisms
Authors: Boyd Stephen A. , Fathepure Babu Z. , Tiedje James M. 
Published: March 2010

Abstract
The anaerobic dechlorination of 4-chlororesorcinol (4-Cl-Res) to resorcinol (1,3-dihydroxybenzene) by fresh anaerobic digester sludge and by an enriched microbial culture was studied. Complete dechlorination of 50 ppm 4-Cl-Res in fresh sludge required about four weeks and occurred without a lag. An anaerobic community capable of degrading 4-Cl-Res was enriched with 4-Cl-Res as the substrate. Dechlorination of 4-Cl-Res by this enrichment occurred at a relatively low rate (0.3 μmol mg−1 d−1) and after a long lag period (three weeks). Addition of yeast extract or trypticase markedly enhanced the rate of dechlorination. The rate increased from 0.3 μmol mg−1 d−1 in the unamended enrichment to 1.1 to 2.6 μmol mg−1 d−1 in cultures amended with 0.1% yeast extract or 0.1% trypticase. Also, the lag period was reduced from approximately three weeks to less than 2 d. The ability to stimulate reductive dechlorination is important because it demonstrates that this process can be enhanced by carbon additions that may lead to practical schemes for fostering detoxication mechanisms in nature.