bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-invasive electrophysiological monitoring: A sensitive method for detecting sublethal neurotoxicity in earthworms
Authors: Drewes Charles D. , Vining Elizabeth P. , Callahan Clarence A. 
Published: March 2010

Abstract
Earthworms were exposed, by external surface contact, to three chemical pollutants: dieldrin (a known neurotoxicant), dimethyl phthalate and fluorene (a possible neurotoxicant). After 48 h of exposure, LC50 values were determined and compared with concentrations required for sublethal neurotoxic effects on giant nerve fiber conduction velocity and escape reflex function, as assessed by nonin vasive electrophysiological recordings. For dieldrin, sublethal decreases in giant fiber conduction velocity occurred at concentrations as low as 1.4 ppm, whereas much higher concentrations were required for lethality (48-h LC50 = 8,100 ppm). Other sublethal effects of dieldrin included hyperresponsiveness of giant fibers, reduction in giant fiber-mediated muscle potentials, tonic spasms of longitudinal shortening and ataxia. For fluorene, sublethal neurophysiological effects, including reduced conduction velocity and occasional “rebound” spiking of giant fibers, were evident at 100 and 250 ppm. By comparison, the 48-h LC50 for fluorene was 360 ppm. No sublethal neurophysiological effects were evident following treatment with dimethyl phthalate; the 48-h LC50 was 10,900 ppm. The results indicate that noninvasive electrophysiological recording of earthworm escape reflex function can be used as a sensitive means of detecting potential sublethal neurotoxic effects of pesticides and other environmental pollutants in these nontarget organisms.
Effects of copper, nickel and zinc on the life cycle of the caddisfly Clistoronia magnifica (limnephilidae)
Authors: Nebeker Alan V. , Savonen Carol , Baker Rocky J. , McCrady Joel K. 
Published: March 2010

Abstract
The caddisfly Clistoronia magnifica (Banks) (Limnephilidae) was exposed to copper, nickel and zinc in life cycle tests. The copper test included continuous exposure of first-generation aquatic larvae and pupae, second-generation larvae and pupae and third-generation larvae. The aerial adults and eggs were exposed only to body burdens obtained as larvae and pupae. Nickel and zinc tests included first and second-generation exposure. Copper concentrations of ≥17 μg/L prevented completion of the life cycle, and significant reduction in adult emergence occurred at 13.0 μg/L. The no-observed-effect level for copper was 8.3 μg/L. Nickel concentrations of ≥250 μg/L prevented completion of the life cycle. The no-observed-effect level for nickel was 66 μg/L. At the highest zinc concentration (5,243 μg/L), no effects were observed on any of the life stages.
Mutagenicity of bottom sediment from a water reservoir
Authors: Lower William R. , Yanders Armon F. , Underbrink Alan G. , Drobney V. Kay , Marrero Thomas R. , Collins Michael D. 
Published: March 2010

Abstract
The bottom sediment of an earthen water reservoir was found to cause elevated somatic mutation frequencies in the stamen hair system of Tradescantia and a decrease in the transient chlorophyll fluorescence yield in leaves of Tradescantia and Zea mays. The mutation frequencies varied only slightly over time, and remained elevated for 91 d of chronic treatment when compared with controls. Chemodynamic modeling indicates that chemicals, including mutagens, can be transferred effectively from reservoir bottom sediment to water.
Transformation of Bacillus subtilis with DNA-encoding naphthalene degradation from Bacillus megaterium
Authors: Oh S. Y. , Quensen J. , Matsumura F. , Momose H. 
Published: March 2010

Abstract
The ability to degrade [14C]-naphthalene was transferred from Bacillus megaterium to B. subtilis by extracting B. megaterium DNA and introducing it into B. subtilis using the protoplast-polyethylene glycol method. Naphthalene degradation was indicated by the accumulation of water soluble 14C activity and the presence of a unique solvent-extractable metabolite on TLC analysis. In addition, resistance to dibenzofuran, p-chlorobiphenyl, and naphthalene (as demonstrated by lack of growth inhibition by these compounds) was transferred by the same technique. B. megaterium ATCC 13368 and derivatives conditioned to the presence of each of these three chemicals were used as DNA donors. B. subtilis transformants showed greater resistance to the chemical to which the DNA donor B. megaterium had been conditioned.
Bioconcentration of cypermethrin, deltamethrin, fenvalerate and permethrin by Chironomus tentans larvae in sediment and water
Authors: Muir D. C. G. , Rawn G. P. , Townsend B. E. , Lockhart W. L. , Greenhalgh R. 
Published: March 2010

Abstract
The bioconcentration of four synthetic pyrethroid insecticides (cis- and trans-cypermethrin, deltamethrin, fenvalerate and cis- and trans-permethrin) by larvae of the midge Chironomus tentans was studied in sand, silt and clay sediments and water (sediment/water ratio, 1:5). Larvae were exposed for 24 h in sediment and for 48 h in water above sediment that contained 12 to 640 ng/g 14C-labeled cypermethrin and 5 and 50 ng/g of the other compounds. Depuration of radioactivity following transfer to clean sand/water systems was monitored for 96 h. Bioconcentration factors for larvae held in sand ranged from 135 for trans-permethrin to 316 for deltamethrin. Larvae in water above sand accumulated 5- to 15-fold greater concentrations of each pyrethroid than did larvae held in water above silt or clay sediments. The lower bioavailability of each compound to larvae in water above silt and clay was attributed to greater sorption to suspended particulates and to dissolved organic carbon in these systems than in relatively particulate-free sand/water systems. The accumulation of pyrethroids by larvae in silt and clay sediments was best accounted for by the uptake of the dissolved portion of each compound in pore water. Depuration of the four pyrethroids by Chironomus larvae was rapid, with an overall half-life for radioactivity of 27 ± 8 h. Exposure for 24 h in sediments containing 5 ng/g concentrations of each pyrethroid had little effect on the behavior of the larvae, but at higher concentrations the animals were immobilized, although many survived following transfer to depuration experiments.
Toxicity of seven potential polychlorinated biphenyl substitutes to algae and aquatic invertebrates
Authors: Sanders Herman O. , Hunn Joseph B. , Robinson-Wilson Everett , Mayer Foster L. 
Published: March 2010

AbstractLaboratory studies were conducted to determine the acute or chronic toxicity of seven potential polychlorinated biphenyl (PCB) replacement products (six phosphate esters and one water-glycol mixture) to the alga Selenastrum capricornutum and three species of invertebrates. Significant reductions in algal biomass after 14 d of incubation were measured in tests with five phosphate esters at nominal concentrations ranging from 0.10 to 10 mg/L. The acute toxicity of six phosphate esters tested against a daphnid (Daphnia magna), a midge (Chironomus plumosus) and an amphipod (Gammarus pseudolimnaeus) was moderate, ranging from 1.1 to 18.0 mg/L. The water-gylcol mixture was nontoxic to algae and invertebrates at the highest nominal concentration tested (100 mg/L).Chronic toxicity tests based on nominal concentrations indicated that five of the six phosphate esters tested against daphnids reduced survival and reproduction at concentrations ranging from 10 to 56 μg/L. whereas only one of three tested against amphipods significantly reduced growth and survival at concentrations of 31 to 128 μg/L. Emergence of midges exposed to three phosphate esters for 30 d was significantly reduced at concentrations of 36 to 319 μg/L. The water-glycol mixture tested was much less toxic to algae and invertebrates than were the phosphate esters. These data indicate that the potential hazard of phosphate esters to the environment is significantly less than that of PCBs.
Laboratory tests evaluating the effects of cadmium on freshwater protozoan communities
Authors: Niederlehner B. R. , Pratt J. R. , Buikema A. L. , Cairns J. 
Published: March 2010

Abstract
Naturally derived protozoan communities developed on polyurethane foam (PF) substrates were used to evaluate the toxic effects of cadmium. The ability of the communities to resist displacement from a structural equilibrium in acute cadmium exposures was evaluated. The number of species remaining on substrates after 2 d was inversely related to cadmium concentration. The concentration required for a 50% reduction in species number relative to the control (EC50) was 4,000 μg Cd/L. Chronic effects were evaluated by observing the colonization of barren PF islands from a species source (PF epicenter) for 28 d. The species occurring on islands over time and the autotrophic index (AI) of substrate communities were determined. The equilibrium species number on islands declined with increasing cadmium concentrations, and AI increased with cadmium concentration. EC20s for measures of colonization were consistently near 1 μg Cd/L. However, epicenters exposed to 9.5 μg Cd/L were not significantly different from controls in species number or AI. This discrepancy in effect levels between PF islands and epicenters is consistent with a relationship between stress tolerance and successional maturity. Levels of toxicity were consistent and reasonable when compared with other cadmium data. The tests compared favorably to single species toxicity tests in time and cost, yet had the advantages of using indigenous species and incorporating emergent properties of communities, such as predation, competition and succession.
Sensitivity of rainbow trout early life stages to nickel chloride
Authors: Nebeker Alan V. , Savonen Carol , Stevens Donald G. 
Published: March 2010

AbstractFour acute tests (96-h) with juvenile fish and four early life stage tests with embryos and larvae were completed with rainbow trout (Salmo gairdneri). Ninety-six-hour flow-through LC50 values for juveniles ranged from 8.1 to 10.9 mg/L nickel. Two early life stage tests were started with newly fertilized eggs, one test was started with eyed eggs and one test was started with pre-swim-up larval fish. No observed effect levels (NOEL), the highest nickel concentration without statistically significant adverse effects, for the two tests with newly fertilized eggs were less than 35 and 35 μg/L. The NOEL for the tests starting with eyed eggs and larval fish was 134 μg/L nickel. Early life stages were most sensitive when newly fertilized eggs were initially exposed, followed in sensitivity by eyed eggs, larval fish and juvenile fish.
Quantitative structure-activity relationships: Molecular structures and different modes of exposure affecting transport and toxicities of chemicals: QSAR analysis
Authors: Lien Eric J. 
Published: March 2010

AbstractAlthough relatively few systematic studies have been reported on the disposition of various toxicants or pollutants, considerable effort has been devoted to disposition studies on various drugs and simple organic molecules. Our group and others have in the last few years reported the quantitative structure-activity relationships (QSAR) on the absorption, distribution and metabolism of several series of organic compounds. The mathematical model embodies the concept of the pH partition hypothesis and the Sutherland-Einstein diffusion equation, as well as Hansch's parabolic model. For most exogenous molecules of intermediate mol wt (102 to 104), passive diffusion through the lipoprotein barrier appears to be the most important route among the known mechanisms of absorption, with an ideal lipophilic character (log P0) around 0.5 to 3. For polar and/or high mol wt compounds (&gt;104) passage through interstitial space becomes mainly a negative function of log mol wt. High mol wt compounds and strong acids and bases (highly ionized) should not be absorbed readily based on the generalizations obtained. However, this does not eliminate the adsorption or binding of these compounds onto the membrane, or direct tissue damage caused by the strong acidity or basicity. Other mechanisms of absorption such as pinocytosis of liquid droplets and phagocytosis of solids are possible, but no quantitative data are available for analysis. Evidence is also presented to show that strong acids or bases can be absorbed as ion pairs with appropriate counter ions.Specific examples of QSAR using the following general equation and its simplified forms are presentedlog A = -a · (log P)2 + b · log P + c · log (U/D) + d · log mol wt + e · χ + f.The types of compounds discussed include nonelectrolytes, weak acids and bases, cationic molecules, strong acids, surfactants and some high mol wt substances. Relationships of the absorption via different routes (e.g., gastric, intestinal, percutaneous and corneal) are compared.
Quantitative structure-activity relationships for the acute toxicity of chlorobenzenes to Daphnia magna
Authors: Bobra Alice , Shiu Wan Ying , Mackay Donald 
Published: March 2010

Abstract
The relationships between physical-chemical properties of aqueous solubility, octanol/water partition coefficient, vapor pressure, boiling and melting points and Henry's Law constant are discussed and illustrated for the chlorobenzenes. It is suggested that a critical review of such data is an essential component of quantitative structure-activity relationship (QSAR) development and can elucidate the potential for air/water and organism/water partitioning during bioas-says. Experimental 48-h EC50 data are reported for Daphnia magna in a closed system and relationships established between EC50, solubility and octanol/water partition coefficient. It is suggested that when presenting QSAR data, logarithmic plots should be prepared of the toxic concentration versus both solubility and octanol/water partition coefficient. The results indicate that in this case the toxic effect is nonspecific in nature and that the EC50 is controlled primarily by organism/water partitioning.
A field test of the exams model in the Monongahela River
Authors: Pollard James E. , Hern Stephen C. 
Published: March 2010

Abstract
Although there are many aquatic fate and transport models that predict environmental concentrations of pollutants over time or distance, the science of model validation is in its infancy. It has been recommended that high priority be given to future experimental work to field-validate existing models. This article presents a comparison of model predictions of phenol concentration downstream from a steel mill effluent derived from the Exposure Analysis Modeling System (EXAMS) with ambient phenol concentration data collected from the Monongahela River in Pennsylvania.
The model predicted oxidation and biolysis as the most significant fate pathways for phenol degradation in the Monongahela River. Bacterial numbers were very low in river water, however, reducing the importance of the biolysis pathway. Agreement between observed levels of phenol and predicted model output was best achieved when a first-order decay of total molar oxidants in the water column was simulated by altering EXAMS molar oxidant input values.
Variation in tissue burdens of polycyclic aromatic hydrocarbons in indigenous and relocated oysters
Authors: Pittinger Charles A. , Buikema Arthur L. , Hornor Sally G. , Young Roderick W. 
Published: March 2010

Abstract
Levels of polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography in indigenous oysters (Crassostrea virginica) from three rivers in the southern Chesapeake Bay. Accumulation and depuration rates of PAHs in oysters were measured in situ by relocation experiments between industrially impacted and nomimpacted sites. Elizabeth River oysters at Norfolk, Virginia, contained the highest PAH tissue burdens among oysters from the rivers sampled; the sum of six PAHs identified was 3 9 ppm dry weight. PAH levels in James River oysters ranged from 0 to 2 3 ppm at Wreck Shoals near Newport News, Virginia No PAHs were detected in oysters from the Piankatank River In accumulation experiments, PAH levels increased from 0 to as much as 11 7 ppm dry weight within 3 d of exposure in the Elizabeth River, they then stabilized Depuration or transformation of PAHs in Elizabeth River oysters to undetectable levels occurred within 4 d of relocation to the Ware River Differences in oyster PAH levels generally corresponded with the degree of industrial and urban development and shipping traffic in the habitats.
A comparison of the effect of four benchmark chemicals onDaphnia magnaandCeriodaphnia dubia-affinistested at two different temperatures
Authors: Cowgill U.M. , Takahashi I.T. , Applegath S.L. 
Published: March 2010

AbstractThe purpose of this study was to compare the sensitivity of Ceriodaphnia dubia/affinis with that of Daphnia magna to chlorobenzene, phenol, diethanolamine and ethylene glycol at 20 and 24°C. Static acute toxicity tests (48-h) were carried out at these temperatures in environmental chambers devoted only to toxicity studies. The majority of toxicity tests were carried out non-concurrently, in triplicate, and in each triplicate series the concentrations were randomly assigned within the appropriate ranges.Response differences of the two organisms at the two test temperatures to the four benchmark chemicals are of the same order of magnitude in each case. D. magna exhibited no statistically significant difference in its response to phenol, diethanolamine and ethylene glycol at the two test temperatures. However, D. magna is less sensitive to chlorobenzene at 24°C than at 20°C. C. dubia/affinis is more sensitive to phenol, diethanolamine and ethylene glycol at 24°C than at 20°C. Like D. magna, C. dubia/affinis is less sensitive to chlorobenzene at 24°C than at 20°C, but the difference for the latter is not statistically significant.A comparison of the two organisms shows that C. dubia/affinis is more sensitive to the four benchmark chemicals at 24°C than at 20°C. At 20°C, C. dubia/affinis is more sensitive to chlorobenzene and ethylene glycol than is D. magna, but the response to phenol and diethanolamine is the same for both organisms.
Phytotox database evaluation of surrogate plant species recommended by the U.S. environmental protection agency and the organization for economic cooperation and development
Authors: Fletcher John S. , Muhitch Michael J. , Vann David R. , McFarlane James C. , Benenati Francis E. 
Published: March 2010

Abstract
The U.S. Environmental Protection Agency and the Organization for Economic Cooperation and Development have recommended or are considering recommendations for phytotoxicity testing. A study was conducted to determine the amount of quantitative data published on the species suggested in those tests. Also, the sensitivity to herbicide applications was examined by use of a computerized database, PHYTOTOX, developed at the University of Oklahoma. The format and content of this database permitted an analysis of data reported in more than 3,500 publications. Such a comprehensive consideration of data was possible only through the use of the PHYTOTOX database and, as a result, the computer analysis reported herein can be viewed as a novel approach in addressing plant toxicology questions.
Although 23 plant species were considered, adequate data for making toxicological comparisons were available for only six species: oat, wheat, corn, sorghum, cucumber and soybean. Oat and wheat, which are monocotyledons, gave the most sensitive responses to the widest range of plant herbicides. Cucumber was the most sensitive dicotyledon evaluated. Corn and soybean appeared to be relatively insensitive.
The lack of published information on most of the recommended plants emphasized the need for additional toxicological studies to establish the merit of using these plants for chemical screening assays.
Differential toxicity and uptake of two fenvalerate formulations in fathead minnows(Pimephales promelas)
Authors: Bradbury Steven P. , Coats Joel R. , McKim James M. 
Published: March 2010

AbstractThe influence of the commercial emulsifier on the acute toxicity and uptake of fenvalerate [(R,S)-α-cyano-3-phenoxybenzyl(R,S)-2-(4-chlorophenyl)-3-methylbutyrate], a synthetic pyre-throid insecticide, by fathead minnows (Pimephales promelas) was examined. Flow-through acute toxicity testing with measured concentrations of technical-grade fenvalerate and a 30% active ingredient emulsifiable concentrate (EC) of the insecticide was conducted. Steady-state LC50 values were reached by 72 and 120 to 168 h, respectively, in tests with technical-grade and EC formulations of this insecticide. Initially, technical-grade fenvalerate was more toxic; the 96–h LC50s for technical-grade fenvalerate and the EC were 0.69 and 0.99 μg/L, respectively. By 168 h, an LC50 of 0.75 μg/L was determined for the EC, indicating that the incipient lethalities of the two formulations were similar. Fenvalerate concentration factors and residue levels in fish showed no significant differences between formulations. Residue levels associated with mortality decreased slightly with increasing fenvalerate water concentrations and ranged (mean) from approximately 1,000 to 1,500 ng/g. Levels in fish that survived testing increased with increasing exposure concentrations and ranged from about 600 to 900 ng/g. Concentration factors of 187 to 1,860 were calculated, with a mean of 1,670, as determined from fish that survived testing. The time required to accumulate residues was greater with the EC and contributed to a significantly slower uptake rate. Slower fenvalerate uptake in the presence of emulsifiers seemingly resulted in the initially lower toxicity of the EC formulation.
Accumulation of zinc by rainbow trout as influenced by pH, water hardness and fish size
Authors: Bradley R. W. , Sprague J. B. 
Published: March 2010

Abstract
The intrinsic toxicity of zinc within fish may be defined as the amount of zinc present in the gills (the site of acute toxicity) at death. This intrinsic toxicity was similar in rainbow trout (Salmo gairdneri Richardson) that were exposed to zinc in acid or neutral water (pH 5.5 or 7.0) and in hard or soft water (total hardness 390 or 30 mg CaCO3/L). Since much more zinc was needed in the water to cause death at low pH and at high hardness, these conditions must alter the uptake and/or excretion dynamics of zinc in gill tissue to produce a slower rate of zinc accumulation. Additional evidence supporting this conclusion is presented. A 17-fold increase in fish size, from 1.7 to 29.0 g, reduced tolerance of zinc by a factor of 3.2, whereas a 14-fold increase in fish size, from 1.3 to 18.2 g, reduced the median lethal time by a factor of 2.7. This reduced tolerance and resistance in larger fish appeared to result from increased intrinsic toxicity of zinc. All sizes of fish showed similar rates of zinc accumulation in the gills, of about 40 μg/g · h.
Biodegradation of chemicals in the subsurface environment: Influence of microbial adaptation on the fate of organic pollutants in ground water
Authors: Wilson John T. , McNabb James F. , Cochran Jack W. , Wang T. Helen , Tomson Mason B. , Bedient Philip B. 
Published: March 2010

Abstract
A plume of contaminated groundwater originating from an abandoned disposal pit for wood-creosoting waste was characterized. The important organic contaminants in the plume include naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, dibenzofuran and fluorene at individual concentrations of 1,000 to 100 μg/L. Core material from the site was studied to determine if organisms in the subsurface could adapt to this waste and if biological activity influenced the disposition of the plume. Biodegradation of these organic pollutants in subsurface material from the margin of the plume was rapid. No biodegradation of the pollutants was detected in pristine subsurface material from the same geological structure. As a result of this adaptation, the disposition of the plume was not controlled by the rate of utilization of the pollutants by the microorganisms but by the extent of utilization allowed by the supply of oxygen.