bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate of fenthion in salt-marsh environments: I. Factors affecting biotic and abiotic degradation rates in water and sediment
Authors: Cripe C. R. , O'Neil E. J. , Woods M. E. , Gilliam W. T. , Pritchard P. H. 
Published: March 2010

Abstract
Fenthion (Baytex), an organophosphate insecticide, is frequently applied to salt-marsh environments to control mosquitoes. Shake-flask tests were used to study rates of abiotic and biotic degradation of fenthion and the environmental parameters that affect these rates. Water or water-sediment (500 mg dry weight/L) slurries from salt marshes located along the Northwest Florida Gulf Coast were used. Flasks contained 200 μg fenthion/L, and degradation rates were determined by following decrease of fenthion over time. Hydrolysis and biodegradation in water were relatively insignificant fate processes; fenthion disappeared from flasks containing water, formalin-sterilized water, or formalin-sterilized sediment very slowly (half-life ≥ 2 weeks). The presence of nonsterile sediment resulted in a rapid exponential disappearance of fenthion (half-life ≥ 3.8 d). Biodegradation was assumed since sterile sediment systems showed a much slower decrease of fenthion, and the production of polar compounds (hexane-unextractable) from radiolabeled fenthion was greater in the presence of sediment than sterilized sediment. The effect of environmental pH levels (5.0–7.0) on degradation was insignificant. No biotic degradation occurred at low oxygen concentration. An 8°C decrease in incubation temperature decreased the rate of sediment biodegradation 2.5-fold. Light caused a slight, but significant, increase in the biotic and abiotic degradation rates of fenthion in water. A two-fold variation in sediment-mediated degradation was noted among sediment samples from three stations within one field site. Inclusion of whole marsh plants or plant parts increased the disappearance rate of fenthion in test systems.
Measurement of zinc amelioration of cadmium toxicity in Chlorella pyrenoidosa using turbidostat culture
Authors: Bennett William N. , Brooks Arthur S. 
Published: March 2010

Abstract
The amelioration of cadmium toxicity by zinc was measured in terms of changes in the maximum specific growth rate (μmax) of a Chlorella pyrenoidosa population using turbidostat culture. In this continuous culture system, μmax is a dependent variable that responds directly to toxic effects. At a sublethal cadmium concentration (2.05 μM Cd) in the medium, the population μmax was in steady state at 70% of control values. When zinc was added to the medium to a concentration of 4.08 μM Zn, μmax increased immediately to a rate of 2.2% of control μmax/generation for seven generations, reaching steady state at 90% of the control. Additional increases in zinc did not elicit further increases in μmax. Full recovery of μmax subsequently occurred after five generations in control medium. Mean cell size and percentage dry mass also changed during periods of toxicity and amelioration. Mechanisms of the amelioration process are discussed.
Toxic effects of boron on mallard reproduction
Authors: Smith Gregory J. , Anders Velora P. 
Published: March 2010

Abstract
Boron, a naturally occurring trace element generally considered environmentally innocuous, was documented to severely impair mallard reproduction. Boron is leached from irrigated agricultural soils and transported in drainage water that contaminates wetlands. Until now, only the selenium accumulated in aquatic food chains has been documented to pose a toxic hazard to wildlife in drainage water wetlands. Adult mallard (Anas platyrhynchos) ducks were fed diets supplemented with 0, 30, 300 or 1,000 ppm boron (fresh weight; diets contained about 10% moisture). The hatching success of fertile eggs was significantly reduced by 1,000 ppm boron, less than one-third the highest boron concentrations found in plants in California's San Joaquin Valley. Hatching weights, duckling survival and duckling weight gain were also reduced by 1,000 ppm boron. Boron concentrations in mallard egg, liver and brain tissues were dose-related. Boron did not affect adult survival or egg fertility. Management of drainage water-contaminated environments must now also consider the adverse effects of boron, as well as the possible interactions of drainage water contaminants.
Computer data bases for carcinogenicity and risk assessment
Authors: Sidhu Kirpal S. 
Published: March 2010

Abstract
This paper reviews information on computer data bases for carcinogenicity and risk assessment. The data bases included were Chemical Evaluation Search and Retrieval System (CESARS), Hazardous Substances Data Bank (HSDB), Registry of Toxic Effects of Chemical Substances (RTECS), Toxicology Information Online (TOXLINE), Cancer Literature (CANCERLIT), Chemical Carcinogenesis Research Information System (CCRIS), Public Health Risk Evaluation Database (PHRED) and Integrated Risk Information System (IRIS). Chemical records included in CESARS, HSDB and RTECS contain general information on carcinogenicity. TOXLINE and CANCERLIT are bibliographic data bases for toxicological and cancer studies. CCRIS contains detailed information on carcinogenicity studies for formulation of risk assessment. PHRED contains toxicological information and cancer potency factors for formulation of risk assessment. IRIS provides detailed information for carcinogenicity assessments, slope factors, unit risks and concentrations at specified risk levels for chronic exposures to carcinogens. IRIS serves as the best source of information for risk assessment for environmental contaminants.
Responses of green frog (Rana Clamitans) tadpoles to lead-polluted water
Authors: Taylor Douglas H. , Steele Craig W. , Strickler-Shaw Shari 
Published: March 2010

Abstract
Green frog (Rana clamitans) tadpoles were exposed to 0, 500, 750 and 1,000 μg Pb/L (as lead nitrate) for 6 d (144 h). Previous studies have shown that similar exposure to 750 or 1,000 μg Pb/L produces deficiencies in both acquisition and retention of learned responses in green frog tadpoles. We examined preference/avoidance responses and spontaneous locomotor activity of Pb-exposed and control tadpoles to plumes of Pb-polluted water at each concentration in an octagonal fluviarium. Results indicated no significant preference or avoidance of Pb by either control or Pb-exposed animals, and no significant effects on the amount of locomotor activity. However, there was significantly greater (p &lt; 0.05; folded Ftest) variability in locomotor activity for tadpoles exposed to 750 and 1,000 μg Pb/L compared to control animals and to those exposed to 500 μg Pb/L.
Ambient toxicity dynamics: Assessments using Ceriodaphnia dubia and fathead minnow (Pimephales promelas) larvae in short-term tests
Authors: Stewart A.J. , Kszos L.A. , Harvey B.C. , Wicker L.F. , Haynes G.J. , Bailey R.D. 
Published: March 2010

Abstract
Seven-day-static-renewal tests with fathead minnow larvae (Pimephales promelas) and Ceriodaphnia dubia were conducted monthly and results were used to assess spatiotemporal patterns in toxicity at 15 sites in five streams that receive discharges from the Oak Ridge National Laboratory (ORNL). The stream-water samples were also analyzed for pH, conductivity, alkalinity, hardness and total residual chlorine (TRC). Relationships between the ambient toxicity test results and the chemical data were evaluated by (a) examining correlations between the two data sets across all site-test combinations and (b) principal components analyses (PCA). These approaches proved to be more appropriate than procedures typically used to evaluate effluent toxicity (e.g., analysis of variance followed by Dunnett's test or Fisher's exact test).
On average, P. promelas growth and C. dubia fecundity differed little from site to site, but survival of the two species varied greatly from test to test at some sites. Mean survival and its site-specific C.V. were inversely related both for C. dubia and P. promelas (r = -0.857 and -0.810, respectively), and the slope of this relationship was greater for C. dubia than it was for P. promelas. Thus, (a) mortality patterns for both test species suggested that episodic events controlled overall patterns in ambient toxicity and (b) the C. dubia test appeared to be more sensitive than the P. promelas test.
PCA identified two water quality factors (axis I, associated with hardness–conductivity, and axis II, strongly associated with TRC) that accounted for 60.5 and 17.6%, respectively, of the total variance in the chemical data. Multiple regression analyses of toxicity test response variables in relation to the two PCA factors showed that C. dubia survival was linked to axis II (p = 0.001) but not to axis I (p = 0.10). C. dubia fecundity was linked significantly to both (p = 0.011 and p = 0.019 for axes I and II, respectively). Neither survival nor growth of P. promelas was linked statistically to either axis. Occurrence-frequency distributions for TRC showed that concentrations high enough to kill either species were exceeded, on average, twice monthly at sites where survival of C. dubia and P. promelas tended to be low. Thus, TRC, which enters ORNL streams primarily as drinking water used in once-through cooling systems, was implicated as a toxicant governing the ambient toxicity test outcomes.
QSAR analysis of the acute fish toxicity of organic phosphorothionates using theoretically derived molecular descriptors
Authors: Schüürmann Gerrit 
Published: March 2010

Abstract
The 14-d LC50 toxicity to the guppy of ten O,O-dimethyl O-phenyl phosphorothionate pesticides is analyzed with respect to linear two-parameter quantitative structure-activity relationship (QSAR) models containing partitioning and reactivity descriptors. The use of quantum chemical parameters within the modified neglect of diatomic overlap (MNDO) scheme leads to QSAR models with correlation coefficients up to 0.95 that are based solely on theoretically derived descriptors. Furthermore, the results show that quantum chemical descriptors have a particular value in modeling chemical reactivity within homologous series of compounds.
Ecological fate, effects and prospects for the elimination of environmental polychlorinated biphenyls (PCBs)
Authors: Hooper Scott W. , Pettigrew Charles A. , Sayler Gary S. 
Published: March 2010

Abstract
Polychlorinated biphenyls (PCBs) present an environmental health hazard of global scale and man-made origin. Their impact on nearly every member of the biota results in a wide range of interacting negative effects. Due to their chemical nature, these recalcitrant toxicants are poised to enter and bioaccumulate in the food web. Recent advances in biodegradation research and molecular biology have shown that natural microorganisms and genetically modified bacterial strains could be used to decontaminate PCB-containing sites. The aim of this review is to summarize the chemistry, environmental fate and toxicological effects of PCBs and to evaluate the currently available technologies for nondisruptive elimination of PCBs from the environment.
Biodegradation of 2-furaldehyde under nitrate-reducing and methanogenic conditions
Authors: Knight Elaine V. , Novick Norman J. , Kaplan Donna L. , Meeks J. R. 
Published: March 2010

Abstract
Nitrate-reducing and methanogenic microbial consortia capable of using 2-furaldehyde (furfural) as a sole source of carbon and energy were isolated from a mixture of soil and municipal sewage and from municipal anaerobic digestor sludge, respectively. Under nitrate-reducing conditions, more than 97% of the furfural was biodegraded in 0.25, 1.5, 4 and 32 d at initial substrate concentrations of 0.5, 5, 50 and 500 ppm, respectively. In all cases microbial populations were able to reduce furfural levels to less than the detection limit of 20 ppb as measured by HPLC. At 500 ppm, there was a 12-d lag period before detectable activity was noted, while there was no lag period at the lower concentrations tested. When the disappearance of both furfural (50 ppm) and nitrate was measured, the molar ratio of nitrate to furfural consumed was approximately 4.2:1, Which is in good agreement with the theoretical ratio of 4.0:1. The biodegradation of furfural was generally more rapid under methanogenic than under nitrate-reducing conditions. The methanogenic consortium was able to metabolize 97% of the furfural in 2, 4, 48 and 144 h at initial concentrations of 0.5, 5, 50 and 500 ppm, respectively. No lag period was noted at any concentrations tested. As under nitrate-reducing conditions, populations were able to reduce furfural levels to less than 20 ppb. Complete metabolism of furfural in cultures that received an initial concentration of 50 ppm resulted in the production of 0.056 mM methane or 43% of the theoretical yield that would result from complete conversion of the material to carbon dioxide and methane. This is the first report of the biodegradation of furfural under nitrate-reducing conditions.
Influence of light intensity and photoadaptation on the toxicity of PCB to a marine diatom
Authors: Ruben Howard J. , Cosper Elizabeth M. , Wurster Charles F. 
Published: March 2010

Abstract
An investigation of the influence of light intensity and photoadaptation on the toxicity of polychlorinated biphenyls (PCBs) to the marine diatom, Ditylum brightwellu, was undertaken Cultures were adapted to six light intensities (30, 50, 75, 100, 125 and 150 μEm 2s−1) for a period of three months During this time a significant decrease in cell size occurred at the lower light intensities (The cultures grown at 30, 100 and 150 μEm 2s−1 were then tested for sensitivity to 10 μg/L PCB ) Rates of growth and photosynthesis (uptake of [14C]HCO3/μg Chl a/h) and cellular concentrations of chlorophyll a and carotenoids, as well as cell size, were measured
PCB toxicity was greatest at the higher light intensities Adapted cultures were less sensitive to PCB than unadapted cultures indicating that photoadaptation increased tolerance to PCB In the unadapted cultures growth rates and photosynthetic activity were significantly depressed by all PCB treatments In the adapted cultures growth rate at 150 μEm 2s−1 was the only measurement to show a significant decrease with PCB treatment Cellular concentrations of chlorophyll a and carotenoids varied with adaptation history, light intensity and PCB treatment
[14C]PCB (Aroclor 1254) accumulation was compared in adapted and nonadapted cultures The nonadapted cultures accumulated an order of magnitude more PCB, and the greatest accumulations correlated with reduced rates of photosynthesis and growth in cultures grown at the highest light levels
Human health effects of metals in drinking water: Relationship to cultural acidification
Authors: Nordberg Gunnar F. 
Published: March 2010

Abstract
Under certain conditions high concentrations of lead or cadmium in drinking water have occurred as a result of contamination from piping and distribution systems Contamination has led to acute and chronic toxicity in humans Metal concentration is increased when the acidity and corrosivity of water increase due to cultural acidification Adverse health effects have occurred in sen sitive subsections of human populations exposed to lead contaminated acidic water Neutralization of the acidity can reduce these problems Acidic water may also dissolve copper from piping systems Cirrhosis of the liver has been reported in children in India (Indian Childhood Cirrhosis – ICC), commonly with fatal outcome High liver copper levels in ICC cases have been related to copper exposure from cooking utensils Some rare cases reported from Germany and Italy have been partly attributed to high concentrations of copper in drinking water and partly to a special sensitivity to copper toxicity Elevated aluminum concentrations may occur in acidified natural waters and as a result of the aluminum chemicals used in drinking water purification Use of water con taming high aluminum levels for dialysis may give rise to dialysis dementia and disorders of bone mineral metabolism A possible relationship between aluminum in drinking water and Alzheimer's disease requires further investigation
Control of cadmium levels in Holopedium gibberum (crustacea, cladocera) in canadian shield lakes
Authors: Yan Norman D. , Mackie Gerald L. , Grauds Peter 
Published: March 2010

Abstract
Cadmium concentrations (Cd-h) of Holopedium gibberum (Crustacea, Cladocera) collected from 26 Canadian Shield lakes with positive alkalinity ranged from 0.9 to 31 μg/g. Levels were positively correlated with aqueous Cd concentrations (Cd-aq) and negatively correlated with clutch size. Animals collected from acidified lakes did not have elevated Cd-h concentrations despite elevated Cd-aq levels. In three intensive study lakes, the presence of eggs lowered Cd-h concentrations and Cd-h levels frequently increased with increases in body size. In two of these lakes, many H. gibberum occupied waters rich in particulate iron just above the anoxic interface. Cd-h levels fell when animals were experimentally confined to this layer, presumably because much of the Cd-aq was adsorbed by the particulate iron and was unavailable for uptake. We suggest that the behavior of animals, specifically their movement to light-scattering layers just above the anoxic interface, influences the accumulation of Cd by H. gibberum in Canadian Shield lakes.
Partitioning and bioavailability of mercury in an experimentally acidified wisconsin lake
Authors: Wiener James G. , Fitzgerald William F. , Watras Carl J. , Rada Ronald G. 
Published: March 2010

Abstract
We studied the partitioning of mercury (Hg) among air, water, sediments and fish at Little Rock Lake, a clear water seepage lake in north-central Wisconsin. The lake was divided with a sea curtain into two basins, one acidified with sulfuric acid to pH 5.6 for two years and the other an untreated reference site (mean pH 6.1), to document the effects of acidification. Trace-metal-free protocols were used to measure Hg at the picomolar level in air and water. Total gaseous Hg in air samples averaged 2.0 ng/m3. Total Hg in unfiltered water samples collected in 1986 after the fall overturn averaged about 1 ng/L in the acidified and reference basins. Mercury in surficial sediments was strongly correlated with volatile matter content and ranged from 10 to about 170 ng/g (dry weight) in both basins. Total Hg concentrations in whole, calendar age-1 yellow perch (Perca flavescens), sampled after one year of residence in the lake, averaged 114 ng/g (fresh weight) in the reference basin and 135 ng/g in the acidified basin – a highly significant (p &lt; 0.01) difference. The mean whole-body burden (quantity) of Hg in age-1 perch did not differ between basins after the first year, but was significantly greater in the treatment basin than in the reference basin after the second year of acidification. Differences between the two basins in the bioaccumulation of Hg were attributed to internal (within-lake) processes that influence the bioavailability of the metal. An initial Hg budget for the treatment basin of Little Rock Lake showed that atmospheric deposition and sedimentary remobilization of Hg are potentially important processes influencing its biogeochemical cycling and uptake by fish.
Effect of body size on the uptake and bioconcentration of di-2-ethylhexyl phthalate in rainbow trout
Authors: Tarr Bryan D. , Barron Mace G. , Hayton William L. 
Published: March 2010

Abstract
Three groups of rainbow trout (Salmo gairdneri) having average body weights of 2.9, 61 and 440 g were exposed at 12°C by the water to di-2-ethylhexyl phthalate (DEHP). The kinetics of uptake and bioconcentration were characterized in each group using a compartmental model. Most of the model parameters, when expressed per unit body weight, were similar in the three sizes of fish. The two major exceptions were the uptake rate parameter, a measure of the capacity of the gill to extract DEHP from water and the apparent size (volume of distribution) of the large DEHP storage compartment, which is a measure of the capacity of the fish to accumulate DEHP. The values of these parameters declined as body weight increased; they followed the allometric equation with body weight exponents of 0.44 and 0.77, respectively. The body weight-associated changes in the pharmacokinetic parameters caused the bioconcentration factor to decline as body weight increased, from 51.5 to 1.6.
Comparative evaluation of five toxicity tests with sediments from san francisco bay and tomales bay, california
Authors: Long Edward R. , Buchman Michael F. , Bay Steven M. , Breteler Ronald J. , Carr R. Scott , Chapman Peter M. , Hose Jo Ellen , Lissner Andrew L. , Scott John , Wolfe Douglas A. 
Published: March 2010

AbstractThe relative sensitivity, analytical precision, discriminatory power and concordance among endpoints and with sediment chemistry were compared among five sediment toxicity tests. The tests were performed with aliquots of 15 composited, homogenized sediment samples. Survival and a variety of sublethal endpoints were determined in tests performed with the amphipods Rhepoxynius abronius and Ampelisca abdita, embryos of the mussel Mytilus edulis, embryos of the urchin Strongylocentrotus purpuratus, and the polychaete Dinophilus gyrociliatus. Each sample was also tested for trace metal and organic compound concentrations, organic carbon content and texture. Two of the five tests (survival among M. edulis and survival among R. abronius) were highly sensitive to the samples and had relatively high precision, but the results were correlated most highly with sedimentological variables. One of the tests (survival among A. abdita) was relatively insensitive, but the results were highly correlated with only the concentrations of toxic chemicals. The test with S. purpuratus indicated mutagenicity in several samples that had high hydrocarbon concentrations. The test of pore water with D. gyrociliatus was intermediate in sensitivity and precision and not correlated highly with the results from the other tests.
Are laboratory-derived toxicity data for freshwater algae worth the effort?
Authors: Lewis Michael A. 
Published: March 2010

Abstract
Algal toxicity test results are increasingly being considered in the evaluation of the environmental safety of chemicals and effluents. The ability of the current standard toxicity test methods to provide data useful in the safety assessment process was reviewed. It was concluded that there are too few data supporting the environmental relevance of those results derived using the standard methods in their present format. The current algal toxicity data base shows that interspecific variation in response to chemicals is significant and that field-validation of most laboratory-derived results is lacking. Therefore, multiple test species should be used in algal toxicity tests and the biological significance of the recommended end points, including stimulation, needs definition before the results can be expanded to natural algal communities and be useful in predicting environmental impact.