bluuebunny/crossref_metadata_2025_split huggingface dataset:
A 2-d Life cycle test with the rotifer Brachionus calyciflorus
Authors: Snell Terry W. , Moffat Brian D. 
Published: March 2010

Abstract
A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly &lt;10%. The comparative sensitivity of the rotifer life cycle test is not yet fully characterized, but for the five compounds compared in both Ceriodaphnia and Brachionus, the chronic values of four were within a factor of six of one another. At the chronic value concentrations of 11 toxicants tested in rotifers, there was on average a 33% reduction in r as compared to controls.
Physico-chemical factors influencing ethyleneamine sorption to soil
Authors: Davis John W. 
Published: March 2010

Abstract
Batch equilibrium studies were conducted with 1,2-ethanediamine (EDA) and N-(2-aminoethyl)-1,2-ethanediamine (DETA) to examine the physico-chemical factors that influence the sorption of the amines to soil. Sorption isotherms were generated using a variety of surface and subsurface soils. The results from this investigation demonstrated that, despite their miscibility in water, both EDA and DETA sorbed strongly to soil. The rate of sorption for both amines was fairly rapid, and equilibrium was achieved within several hours. Sorption isotherms could be best described by the Freundlich equation, and a series of Freundlich constants, Kd's, were developed for each soil and amine. Sorption of the ethyleneamines correlated closely with the cation exchange capacity (CEC) and organic content of the soil. Soils with increased CEC and organic content exhibited higher affinities for the amines. This dependence of sorption on CEC and organic content was most likely due to the strong electrostatic interaction between the positively charged amine and the negatively charged soil surface. For all soils DETA sorbed more strongly than EDA, although the sorption constants varied over an order of magnitude for both compounds. In order to decrease the variation observed in the Kd values, the sorption constants were normalized to the organic carbon content of the soil and unique Koc values were developed for each amine. The average Koc values for EDA and DETA were 4,766 and 19,111, respectively.
Contaminated marine sediments: Water column and interstitial toxic effects
Authors: Burgess Robert M. , McKinney Richard A. , Schweitzer Kate A. , Phelps Donald K. 
Published: March 2010

Abstract
The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentrations of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial waters did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.
Prediction of biodegradation kinetics using a nonlinear group contribution method
Authors: Tabak Henry H. , Govind Rakesh 
Published: March 2010

Abstract
The fate of organic chemicals in the environment depends on their susceptibility to biodegradation. Hence, development of regulations concerning their manufacture and use requires information on the extent and rate of biodegradation. Recent studies have attempted to correlate the kinetics of biodegradation with the molecular structure of the compound. This has led to the development of structure-biodegradation relationships (SBRs) using the group contribution approach. Each defined group present in the chemical structure of the compound is assigned a unique numerical contribution toward the calculation of the biodegradation kinetic constants. In this paper, a nonlinear group contribution method has been developed using neural networks; it is trained using literature data on the first-order biodegradation kinetic rate constant for a number of priority pollutants. The trained neural network is then used to predict the biodegradation kinetic constant for a new list of compounds, and the results have been compared with the experimental values and the predictions obtained from a linear group contribution method. It has been shown that the nonlinear group contribution method using neural networks is able to provide a superior fit to the training set data and test data set and produce a lower prediction error than the previous linear method.
Effects of acidification on metal accumulation by aquatic plants and invertebrates. 1. Constructed wetlands
Authors: Albers Peter H. , Camardese Michael B. 
Published: March 2010

Abstract
Compared were concentrations of Al, Cd, Ca, Cu, Fe, Hg, Pb, Mg, Mn, Ni, P, and Zn in water, plants, and aquatic insects of three acidified (pH ∼ 5.0) and three nonacidified (pH ˜ 6.5) constructed wetlands. Concentrations of Zn in water and bur-reed (Sparganium americanum) were higher in acidified wetlands than in nonacidified wetlands. Floating nonrooted plants contained mean concentrations of Fe, Mg, and Mn that were higher than recommended maximum levels for poultry feed. The mean concentrations of all metals in insects were below recommended maximum levels for poultry feed and below levels that cause toxic effects in wild birds. Smaller than expected increases of metal concentrations in the water of acidified wetlands were probably due to limited mobilization of metals from the sediments and insignificant changes in sedimentation of aqueous metals. Calcium was lower in acidified than in nonacidified wetland water, but the Ca content of insects and bur-reed was not lower. Low concentrations of Ca in aquatic insects from both groups of wetlands indicate that calcium-rich crustaceans and mollusks are probably important to female waterfowl and their young during the spring, when invertebrates make up the majority of the diet. Although toxic effects from metal ingestion seem to be unlikely consequences of wetland acidification, the adverse effect of low pH on the occurrence of crustaceans and mollusks could threaten egg production and development of young.
Interlaboratory comparison and optimization of hepatic microsomal ethoxyresorufin O-deethylase activity in white sucker (Catostomus commersoni) exposed to bleached kraft pulp mill effluent
Authors: Munkittrick K.R. , van den Heuvel M.R. , Metner D.A. , Lockhart W.L. , Stegeman J.J. 
Published: March 2010

Abstract
Twelve samples of minced liver from white sucker (Catostomus commersoni) were delivered to 14 laboratories in Canada and the United States for the analysis of hepatic ethoxyresorufin O-deethylase (EROD). Samples were collected from a site exposed to bleached kraft pulp mill effluent (BKME) and from a reference site. All laboratories analyzing EROD activity successfully differentiated between effluent exposed fish (high activity) and reference samples (low activity). Absolute activity detected in samples from the induced site varied greatly with analysis method; assay conditions at most laboratories were suboptimal for white sucker microsomes, and absolute activity of the samples was most affected by pH, temperature, and substrate limitation. The method used to quantify protein was also thought to contribute greatly to the observed variability. However, the induction level (mean exposed divided by mean reference values) was similar. Relative induction did not appear to be affected by storage time, pH, buffer, assay time, or assay temperature. The induction level was not affected by whether postmitochondrial supernatant (PMS; 10,000 g) or microsomal fractions (100,000 g) were used in analysis, although absolute activity was 3.5 times higher with microsomal preparations. There was a statistically significant agreement in the rankings of high-activity samples using microsomal preparations; a corresponding ranking of PMS values was nonsignificant. The presence of cytochrome P4501A enzyme was detected using monoclonal antibody 1-12-3 against scup P4501A1. Immunoblotting showed 8.4-fold differences in the measured levels of the single cross-reacting band, confirming the distinction between exposed and reference fish determined by EROD assay.
The fragile relationship of business and environmental science
Authors: Carpenter George D. 
Published: March 2010

Abstract
The evolution of environmental science has resulted in its politicization. This politicization of science threatens the value of science as a means of answering society's questions and concerns. Therefore, it also threatens the traditionally strong relationship between environmental science and business. To forestall or reverse this threat, the scientific community needs to hold itself accountable for the use of science in the public sphere of social policy and to accept responsibility for explaining its work in terms the public can understand.
Re-exposure of mallards to selenium after chronic exposure
Authors: Heinz Gary H. 
Published: March 2010

Abstract
Adult male mallards (Anas platyrhynchos) were fed a control diet or a diet containing 15 ppm selenium as seleno-D,L-methionine for 21 weeks. After this initial exposure, the mallards were fed untreated food for 12 weeks, then were re-exposed to selenium at 100 ppm for five weeks. During re-exposure to 100 ppm selenium, the birds that had previously been exposed to 15 ppm selenium and those that had not previously been exposed did not differ in percentage of mortality (14.7 and 14.3%), weight loss in survivors (39.3 and 41.2%), selenium concentrations in the livers of survivors (35 and 53 ppm, wet weight), or selenium concentrations in the livers of birds that died (35 and 40 ppm, respectively). When the data from the birds that had previously been exposed to 15 ppm selenium were combined with the data from the birds that had not previously been exposed, selenium concentrations in the livers of birds that had died on the 100-ppm selenium treatment (38 ppm) did not differ from the concentrations in the livers of birds that had survived (43 ppm).
Compatibility of functional groups in Kow-based QSARs: Application to nitro compounds
Authors: Banerjee Sujit , Williams Chris L. 
Published: March 2010

Abstract
Nitro compounds are particularly difficult to handle in simple Kow-based QSARs, owing to differences in their lipid-phase activity coefficients. These differences can be corrected, in part, through inclusion of a term in octanol solubility. A procedure for identifying potentially incompatible groups in a given QSAR is suggested. The quality of a QSAR is best if the interactions of the functional groups involved with octanol fall within a narrow range. These interactions are easily calculated by the UNIFAC method.
Comparison of effluent toxicity results using Ceriodaphnia dubia cultured on several diets
Authors: Norberg-King Teresa J. , Schmidt Shaneen 
Published: March 2010

Abstract
Several diets have been proposed for Ceriodaphnia dubia, but no single diet has been universally accepted as optimal for toxicity testing. Although several diets for Ceriodaphnia dubia cul-turing and testing are commonly used, little or no data exist on whether toxicity varies with the diet. This study evaluated several combinations of yeast-Cerophyl-trout chow (YCT), Selenastrum capricornutum, and Selenastrum capricornutum-Cerophyl foods for routine culture performance and the sensitivity of the offspring in subsequent acute toxicity tests with effluents. Variations in the diets included use of a vitamin-fortified yeast added to the YCT, algae (Selenastrum capricornutum) grown in two different algal media, and different feeding rates of the algae-Cerophyl diets. Eleven diets were evaluated in a multigeneration feeding study, but only seven were used in subsequent toxicity tests. The young produced from each of the seven diets were tested in 48-h acute tests with three different effluents across the generations. Toxicity tests with the effluents gave LC50s that were within a factor of two of one another, regardless of the food used for culturing. These results indicate that several diets are satisfactory for culturing Ceriodaphnia dubia and that the results of the toxicity tests are comparable.
Aluminum bioconcentration at the gill surface of juvenile Atlantic salmon in acidic media
Authors: Wilkinson Kevin J. , Campbell Peter G. C. 
Published: March 2010

Abstract
Aluminum uptake by Atlantic salmon was examined in the laboratory at pH 4.5, under conditions similar to those found in running waters on the Canadian Precambrian Shield during spring snowmelt. Gill uptake of Al was slow, approaching steady state only after 3 d of exposure. The greatest fraction of gill-associated Al was sorbed not to the gill surface itself, but to the gill mucus. Mucus appears to retard Al transport from solution to the membrane surface, thus delaying the acute biological response of the fish. Strongly associated gill [Al] was never greater than 10% of total gill Al in the early stages (&lt;3 d) of the experiment; however, longer experiments (7 d) indicated that this Al fraction could eventually exceed 50% of the total gill Al. In contrast to uptake, depuration of Al was extremely rapid; total gill [Al] of fish exposed to Al (pH 4.5) for 2 d decreased by 60% after only 2 h in an Al-free medium (t1/2 = 0.9 h). The effect of fluoride complexation on Al bio-concentration was also examined. For equivalent Al3+ concentrations, sorption of Al to the gill surface was higher in the presence of fluoride than in its absence, which suggests the formation of mixed ligand [F-Al-L-gill] complexes at the gill surface.
Pesticide inputs and risks in coastal wetlands
Authors: Clark James R. , Lewis Michael A. , Pait Anthony S. 
Published: March 2010

Abstract
Coastal wetland habitats may receive pesticide inputs indirectly from agricultural and forest control of weeds and insects in upland drainage areas; indirectly or directly from weed, insect, and biofouling control from development of adjacent lands for agricultural, recreational, or residential uses; and directly from control activities practiced within wetlands for protection of public health or for nuisance abatement. Persistent and bioaccumulative pesticides used at upland sites have threatened coastal wetland biota. For more biodegradable contemporary pesticides, concerns for ecological impact are more a function of the proximity of the site of application relative to the wetland, and time available for degradation and sorption. In addition, the rate and extent of localized mixing, flushing, and stratification within the wetland can greatly affect exposure concentrations and durations for wetland biota. The short-term, direct toxic effects of pesticides on aquatic biota inhabiting coastal wetlands have been characterized in laboratory and field studies; however, assessment of the cumulative and indirect effects of repeated exposures to multiple chemicals at sublethal concentrations is a major research need.
Inhibition of glucosephosphate isomerase allozymes of the mosquitofish, Gambusia holbrooki, by Mercury
Authors: Kramer Vincent J. , Newman Michael C. 
Published: March 2010

Abstract
Frequencies of allozyme genotypes are being used as population-level indicators of environmental heavy-metal contamination. A genotype of glucose phosphate isomerase, Gpi-238/38, of mosquitofish (Gambusia holbrooki) has been identified as “mercury-sensitive” in an acute toxicity assay. Partially purified preparations of GPI-2 38/38 and GPI-2 100/100 were assayed to determine differences in maximum gluconeogenic reaction velocity at seven mercury (added as HgCl2) concentrations, 15 to 960 nM Hg. Log-Probit analysis of the inhibition curves indicated that the log(IC50) (log10 of the Hg concentration causing a 50% reduction in reaction velocity) for GPI-2 100/100 was significantly lower than that for GPI-2 38/38, even though GPI-2 100/100 initial uninhibited reaction velocity was greater than that of GPI-2 38/38. Although the mechanism of inhibition was not experimentally determined, under the assumption of noncompetitive interaction between Hg and GPI-2, the inhibitor dissociation constants (95% asymptotic C.I.) for GPI-2 100/100 and GPI-2 38/38 were estimated from the log (IC50) as 204 nM Hg (155-269 nM Hg) and 479 nM Hg (363-617 nM Hg), respectively. These results suggested that Hg susceptibility related to the Gpi-238/38 genotype in acute toxicity assays was likely not due to enhanced Hg inhibition of GPI-2 38/38.
Chemical fate and transport in a domestic septic system: Biodegradation of linear alkylbenzene sulfonate (LAS) and nitrilotriacetic acid (NTA)
Authors: Shimp R.J. , Lapsins E.V. , Ventullo R.M. 
Published: March 2010

Abstract
The biodegradation of linear alkylbenzene sulfonate (LAS) and nitrilotriacetic acid (NTA) was assessed in an established septic tank system and an adjoining shallow sand aquifer (located near Cambridge, Ontario). Studies were conducted on soil, aquifer sediment, and groundwater samples from a transect of the septic tank effluent plume. LAS and NTA were readily biodegraded in the vicinity of the discharge, with mineralization half-lives in soil and sediment samples collected near the tile field ranging from 9 to 17 d and 1 to 3 d, respectively. Similar results were obtained for ground water. Adaptation was a key process in the system, as illustrated by the rapid biodegradation near the tile field and limited biodegradation at locations far downgradient or ungradient of the system, where little or no LAS or NTA loading occurred. The results demonstrate that properly functioning septic tank systems can effectively remove synthetic organic chemicals such as LAS and NTA.
Carbofuran residues in grasshoppers and vegetation from aerially sprayed prairie pastures: Potential effects on wildlife
Authors: Forsyth Douglas J. , Westcott Neil D. 
Published: March 2010

Abstract
Deposition and persistence of carbofuran in vegetation and grasshoppers of two prairie pastures were measured after single aerial applications at 134 g a.i per hectare in 1987 and 1988. Mean depositions on horizontal filter paper samplers were 43 1 and 64 9% of the nominal rate in the two applications Variability of deposits, measured as C V.s, were 76 4% and 86 9% Carbofuran residues in vegetation and grasshoppers were less variable than those in deposit samplers, with C V s of 40 6 and 70 6% in vegetation and 58 6 and 32 5% in grasshoppers for 1987 and 1988, respectively. Residues declined by 50% in 24 h both years from initial concentrations (3 h postspray) in vegetation of 13 3 and 10 8 μg/g Initial residues in grasshoppers averaged 2 2 μg/g in 1987 and 3.9 μg/g in 1988; the mean for both years was 2.5 μg/g Grasshoppers contained the same concentration of carbofuran 3 h after spraying, whether collected live or dead Maximum residues of 5 7 μg/g were found in grasshoppers from two of the 40 sites sampled in both years A model fitted to the data indicated that there may have been about a 24 to 44% loss of residues from vegetation, probably due to volatilization and other processes, before samples were collected at 3 h There was a decline in residues per grasshopper of 30% in 24 h both years, which was not evident when expressed as micrograms per gram because of desiccation of the dead insects The concentrations of carbofuran in the vegetation and grasshoppers were typical of aerial spraying, hence, they may be used as baseline values for estimating exposure of herbivores and msectivores to insecticide deposits from similar spray events by adjusting for rate of application Deposits measured on filter papers were positively related to concentrations in vegetation and grasshoppers Calculations of the potential effects on wildlife of ingesting sprayed grasshoppers, combined with other routes of exposure, indicated a relatively low hazard for herbivorous rodents but a relatively high hazard for insectivorous adult passerines and their young Monitoring passerines in a related field study did, however, not reveal any effects on survival within 3 d of spraying carbofuran.
Sublethal responses to pesticides of several species of australian freshwater fish and crustaceans and rainbow trout
Authors: Davies P.E. , Cook L.S.J. , Goenarso D. 
Published: March 2010

Abstract
Sublethal responses of the fish Oncorhynchus mykiss, Galaxias maculatus, Pseudaphritis urvillii, and the crustacean Paratya australiensis to short-term exposures to low concentrations of seven pesticides were compared under identical conditions. Parameters examined were hematocrit, leucocrit, plasma glucose, plasma protein, plasma chloride, muscle RNA and DNA, brain and muscle acetylcholinesterase activity, hepatic glutathione-S-transferase activity, hepatic glutathione, and somatic growth. The organisms were exposed to the following materials–the organophosphate insecticides acephate and fenitrothion; the phenoxyacetate herbicide MCPA-Na; the triazine herbicides atrazine and cyanazine; the fungicide chlorothalonil, and the pyrethroid insecticide cypermethrin–as purified active ingredients in continuous flow through at constant temperature (12–15°C) for 10 or 20 d, with feeding, at five concentrations. Oncorhynchus mykiss was marginally the most sensitive fish species studied in terms of the number of responses to pesticide exposure, but not in terms of the LOECs. Interspecies comparisons indicated that water quality criteria based on juvenile Oncorhynchus mykiss toxicity data alone would not be suitable for the protection of juvenile and adult Galaxias maculatus and Pseudaphritis urvillii from physiological stress in at least three of seven cases. Four of seven maximum acceptable toxicant concentrations (MATCs) derived from physiological responses of fish species resulted from data on Galaxias maculatus and Pseudaphritis urvillii alone. In the case of organophosphates, the decapod crustaceans Paratya australiensis and Astacopsis gouldi were by far the most sensitive. Tentative water quality criteria for the protection of study species from short-term stress are proposed.