bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting algal sensitivity to a pesticide stress
Authors: Kent Robert A. , Currie David 
Published: March 2010

Abstract
Twelve freshwater phytoplankton species were used to investigate the factors affecting the toxicity of the organo-phosphorus insecticide fenitrothion (O,O-dimethyl-O-nitro-m-tolyl phosphorothioate) to algae. The unicellular chlorophytes Ankistrodesmus falcatus, Chlamydomonas segnis, Chlamydomonas reinhardtii, Chlorella pyrenoidosa, Chlorella vulgaris, Cosmarium sp., Pediastrum sp., Scenedesmus obliquus, Selenastrum capricornutum, and Staurastrum sp.; the bacillariophyte Navicula sp.; and the cyanophyte Anabaena sp. were exposed to three concentrations (0.1, 1.0, and 10.0 mg/L) of fenitrothion. Differential growth effects were observed among the species exposed to fenitrothion over short (96 h) and long-term (14 d) durations. Fenitrothion concentrations eliciting a 50% growth reduction over 96 h (EC50) ranged from 0.8 to 24.4 mg/L. Selected properties of the test algae (cell size, lipid content, and bioconcentration capacity) were measured and examined for their relationship to fenitrothion sensitivity. Strong correlations were obtained between fenitrothion sensitivity and cell surface area/volume (S/V) ratios, cell lipid content, and fenitrothion bioconcentration capacity of the cells, suggesting that these attributes may be useful predictors of differential sensitivity to lipophilic xenobiotics in unicellular phytoplankton. A positive relationship observed between cell S/V ratio and the bioconcentration of fenitrothion further implicates algal cell size as a significant factor in alga/pesticide interaction and subsequent vulnerability to lipophilic xenobiotics.
Comparative sensitivity of amphibian tadpoles to single and pulsed exposures of the forest-use insecticide fenitrothion
Authors: Berrill Michael , Bertram Susan , Coulson Donna , Kolohon Mark , Ostrander Dean , Pauli Bruce 
Published: March 2010

Abstract
The insecticide fenitrothion is sprayed twice, 5 to 10 d apart, to control spruce budworm. To assess the effects of pulsed exposure of fenitrothion to different species of amphibians, we exposed 1- and 8-d-old tadpoles of wood frogs, leopard frogs, green frogs, bullfrogs, and American toads, as well as larvae of the spotted salamander, to 2 to 9 ppm of the insecticide for 24 h. Our results indicate that within each ranid species, day-1 and day-8 tadpoles are equally sensitive, and tadpoles exposed twice, on day 1 and day 8, are no more sensitive to the second exposure than to the first. Bullfrog and green frog tadpoles are more sensitive to exposures than are wood frog and leopard frog tadpoles, exhibiting paralysis at lower concentrations, and they are affected by exposure to the carrier compounds as well as the insecticide. The greater sensitivity of the green frog and bullfrog tadpoles correlates with their smaller size and earlier developmental stage at hatching. American toad tadpoles are more tolerant of pu sed exposure to fenitrothion than are any of the ranids, whereas the spotted salamander larvae are as sensitive as are the bullfrog and green frog tadpoles.
The effects of motorway runoff on freshwater ecosystems: 2. Identifying major toxicants
Authors: Maltby Lorraine , Boxall Alistair B.A. , Forrow David M. , Calow Peter , Betton Clifford I. 
Published: March 2010

Abstract
Previous studies have provided prima facie evidence that runoff from the Ml motorway, UK, affects both the quality of the receiving water and the biota living there, in sites short distances from point sources —i.e., possible worst-case situations. Because discharges contain a wide variety of contaminants, both the identification of toxicants and the establishment of causal relationships between observed changes in water/sediment quality and biology are often difficult. In this particular case, the problem was addressed by conducting a series of toxicity tests using the benthic amphipod Gammarus pulex. The abundance of this species was greatly reduced downstream of the point where motorway runoff entered the stream. Stream water contaminated with motorway runoff was not toxic to G. pulex. However, exposure to contaminated sediments resulted in a slight reduction in survival over 14 d, and sediment manipulation experiments identified hydrocarbons, copper, and zinc as potential toxicants. Spiking experiments confirmed the importance of hydrocarbons, and fractionation studies indicated that most of the observed toxicity was due to the fraction containing polycyclic aromatic hydrocarbons. Animals exposed to contaminated sediments and water spiked with sediment extract accumulated aromatic hydrocarbons in direct proportion to exposure concentrations.
Organotins in freshwater harbors and rivers: Temporal distribution, annual trends and fate
Authors: Pent Karl , Hunn Judith 
Published: March 2010

Abstract
The occurrence of butyltin and phenyltin compounds in water, mussels, and sediment of freshwater boat harbors of Lake Lucerne, Switzerland, and six Swiss river systems was determined between 1991 and 1993 following the sales ban of organotin-containing antifouling paints. In harbor waters, average levels of tributyltin (TBT) were between 40 and 50 ng/L in 1993, which was one order of magnitude lower than in 1988. Residues of up to 9.2 μg/g TBT and 0.7 μg/g triphenyltin (TPT) occurred in zebra mussels (Dreissena polymorpha) and were related to the water concentrations. In a sediment core, high levels of TBT and TPT occurred in the upper 7 cm and 5.5 cm, respectively, with significant decreases below. Estimated sedimentation rates and the fact that transformation products did not increase with depth indicate that TBT and TPT are persistent in these sediments. In all rivers, di- and/or monobutyltin of up to 46 ng/L occurred consistently, and occasionally TBT and TPT of up to 26 and 11 ng/L, respectively. This study indicates that even though regulations were effective in reducing TBT and TPT levels in boat harbor water, contamination of surface fresh waters including rivers by organotin compounds is still widespread and has ecotoxicological consequences. Moreover, harbor sediments represent long-term reservoirs of these compounds.
Quantitative structure-activity relationships for evaluating the influence of sorbate structure on sorption of organic compounds by soil
Authors: Hu Qinhong , Wang Xiaojiang , Brusseau Mark L. 
Published: March 2010

Abstract
The purpose of this work was to investigate the effect of sorbate structure, by using the quantitative structure-activity relationship (QSAR) approach, on sorption of organic compounds by two soils with different amounts of organic matter. Miscible displacement experiments were performed with several organic contaminants representing six classes of nonpolar, nonionizable organic chemicals, including chlorinated aliphatics, chlorobenzenes, polycyclic aromatic hydrocarbons (PAHs), n-alkylbenzenes, methylated benzenes, and polychlorinated biphenyls (PCBs). The breakthrough curves were analyzed by using a bicontinuum model wherein sorption is assumed to be instantaneous for a fraction of the sorbent and rate limited for the remainder. The QSAR approach was used to investigate the dependency of both equilibrium and nonequilibrium sorption coefficients on topological descriptors representing structural properties of the solutes. For both equilibrium and nonequilibrium parameters, the first-order valence molecular connectivity (1Xv) was found to be the best topological descriptor. Most of the rate-limited sorption behavior could be explained by accounting for the size and structure of the solute molecule, as indicated by the good correlation between the rate coefficient and 1Xv. This supports the contention that rate-limited sorption in these systems is controlled by a physical diffusion mechanism, consistent with the polymer diffusion model. Based on this model, the calculated diffusion-length ratios for the Borden and Mt. Lemmon soils, which have a large difference in organic-matter contents, compare favorably to the values determined from the measured rate data.
Evaluation of alternative reference toxicants for use in the earthworm toxicity test
Authors: Yeardley Roger B. , Lazorchak James M. , Pence Michael A. 
Published: March 2010

Abstract
The use of the 14-d earthworm toxicity test to aid in the evaluation of the ecological impact of contaminated soils is becoming increasingly widespread. However, the method is in need of further standardization. As part of this continuing process, the choice of reference toxicants was evaluated. Reference toxicants were rated in relation to the following criteria: (a) reproducibility, (b) low human health hazard, (c) feasibility of measurement, and (d) chemical stability. Potassium chloride (KCl) and ammonium chloride (NH4Cl) were evaluated as possible alternatives to the one currently in common use, 2-chloroacetamide. Potassium chloride rated the best for the combination of the four criteria, followed by NH4Cl and 2-chloroacetamide. Coefficients of variation (C.V.s) from control charts of six definitive tests were used to measure reproducibility. The best reproducibility (lowest C.V.) was shown by KCl, followed by NH4Cl and 2-chloroacetamide. Toxicants ranked KCl &lt; NH4Cl ≪ 2-chloroacetamide in terms of health hazard; and KCl = NH4Cl &gt; 2-chloroacetamide in terms of measurement feasibility. Both 2-chloroacetamide and NH4Cl changed in concentration during testing. Evidence is also presented that 2-chloroacetamide degrades rapidly during testing, and that, as dead worms decay, ammonification may be adding another toxicant, ammonia, to tests.
Combinatory effects of temperature stress and nonionic organic pollutants on stress protein (hsp70) gene expression in the freshwater sponge Ephydatia fluviatilis
Authors: Müller Werner E.G. , Koziol Claudia , Dapper Jutta , Kurelec Branko , Batel Renato , Rinkevich Baruch 
Published: March 2010

Abstract
This is the first documentation of a heat shock protein (hsp) response in sponges. Subjecting the freshwater sponge Ephydatia fluviatilis to temperature stress (18° to 33°C; 2 h) resulted in an increased expression (&gt;10 times) of the Mr 70,000 (hsp70). The induction of hsp70 could be demonstrated on the level of gene expression and by quantification of the hsp70 protein. Temperature stress also resulted in a 25% reduction of sponge cell proliferation. A mixture of nonionic organic compounds was extracted from water from the polluted Schwarzbach River (S. Hesse, Germany) by adsorption onto XAD-7 resin. Concentrations of this Schwarzbach River water extract at two and four times ambient levels resulted in decreases in cell proliferation by 53.6 and 99.4%, respectively. However, when cells were exposed to these levels of the Schwarzbach River water extract directly following a temperature stress (33°C for 2 h), cell proliferation was less affected by the extract than the absence of the temperature stress. In addition, the combination of temperature stress and exposure to the Schwarzbach River water extract resulted in higher levels of hsp70 than were observed for each stressor by itself. Northern and Western blotting as well as precipitation assays confirmed the interaction between heat treatment and exposure to different amounts of nonionic organic pollutants on the level of mRNA and protein expression of hsp70. From these data we conclude that a sublethal treatment of sponges with heat results in a higher tolerance of the animals to chemical stressors. These results are relevant to the real-world situation where organisms are often exposed simultaneously to a variety of stressors, in contrast to many laboratory exposures that aim to elucidate the effects of individual stressors.
Comparative photodegradation rates of alachlor and bentazone in natural water and determination of breakdown products
Authors: Chiron Serge , Barceló Damià , Abian Joaquin , Ferrer Marta , Sanchez-Baeza Francisco , Messeguer Angel 
Published: March 2010

Abstract
The photochemical degradation of the herbicides alachlor (2-chloro-2′,6′-diethyl-N-methoxymethylacetanilide) and bentazone (3-isopropyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide) in distilled water and in river water, under xenon arc lamp irradiation, was investigated. Analytical determinations were carried out by using a xenon arc photoreactor and online solid-phase extraction coupled to liquid-chromatography diode-array and liquid-chromatography mass-spectrometry detection systems. Photolysis experiments were performed at low concentration (20 μg/L), and the advantages of this methodology over conventional techniques are discussed. The photodegradation of alachlor and bentazone is a process depending on the water type, humic substances, and pH. When using a solution of 4 mg/L of humic matter, the estimated alachlor and bentazone half-lives were 84 and 150 min, respectively, using a total irradiance of 550 W/m2 in the range of 300 to 800 nm. The degradation of alachlor and bentazone followed pseudo second- and first-order kinetics, respectively. The major photodegradation products of both herbicides were identified either by on-line solid-phase extraction (SPE)-liquid chromatography-thermospray mass spectrometry (LC/TSP-MS) or on-line-SPE-LC/TSP-tandem mass spectrometry (LC/TSP-MS/MS). In addition to that, a total of six transformation products of alachlor were synthesized in our laboratory and their MS spectra were compared with those of the breakdown products obtained. After photodegradation, a total of 14 photoproducts resulted from alachlor dechlorination with subsequent hydroxylation and cyclization processes. The two major photoproducts were identified as hydroxy-alachlor and 8-ethyl-1-methoxymethyl-4-methyl-2-oxo-1,2,3,4-tetrahydroquinone. No significant breakdown products of bentazone could be identified.
Toxicity of aircraft de-icer and anti-icer solutions to aquatic organisms
Authors: Hartwell S. Ian , Jordahl David M. , Evans Joyce E. , May Eric B. 
Published: March 2010

AbstractLaboratory studies were undertaken to assess the toxicity of industrial mixtures of aviation de-icers and anti-icers. Various additives and contaminants are present in these solutions at proportions of 10 to 20% of the total volume. Staticrenewal toxicity tests were performed at concentrations that bracketed published LC50 values for the primary ingredients (9-51 ml glycol/L) using fathead minnow (Pimephales promelas), Daphnia magna, Daphnia pulex, Ceriodaphnia dubia, and Photobacterium phosphoreum (Microtoxr̀) bioassays. Water from a stream that receives runoff from a large commercial airport was also tested during a late winter storm (March), and spring baseflow (April). The anti-icer solution was more toxic than the de-icer solution by two orders of magnitude (96-h LC50 range 0.03–0.44 ml/L, 3.02–13.48 ml/L, respectively). Both types of solutions exhibited greater toxicity than previously reported values for the primary ingredients. Toxic effects were observed in the March stream sample, but not the April sample. Significant inhibition of reproduction in C. dubia in the anti-icer and de-icer solutions occurred at 0.05 and 0.38 ml/L, respectively. Effects were observed in the Microtox assay at concentrations of 0.125 and 0.25 ml/L for the anti-icer and de-icer, respectively. Results suggest that the additives, rather than the glycols, are the major source of toxicity. Histological damage observed in fathead minnows primarily involved gill, kidney, and skin tissue, with the most prominent responses seen in fish exposed to the anti-icer solution. The de-icer solution elicited respiratory epithelial “disruption” and renal damage, and the anti-icer caused proliferative branchitis (hyperplastic response) and delamination of the epidermis from the dermis of the skin.
Overview and rationale for developing regulatory guidelines for nontarget plant testing with chemical pesticides
Authors: Boutin Céline , Freemark Kathryn E. , Keddy Cathy J. 
Published: March 2010

Abstract
In the assessment of ecological risk posed by pesticide use, much greater emphasis has been given to the direct effects on wildlife than on impacts on wildlife habitat. Assessment of indirect effects to wildlife entails an evaluation of pesticide toxicity to plant species (and invertebrates) that make up wildlife habitats. Under the pesticide registration process in Canada and in most other countries, there is no specific requirement for testing the toxicity of pesticides to nontarget plants other than agronomically important species. The proposed nontarget plant testing guidelines summarized in this paper are intended to fill this gap. The chief objectives of the guidelines are to outline data requirements, to suggest methods and approaches for generating the data required, and to facilitate and improve hazard assessment for nontarget plants (and habitats) as a result of chemical pesticide use. The rationale behind decisions reached in the guidelines is also presented. The proposed guidelines are very flexible, as registrants may be granted a waiver for any test required, provided the rationale is justified on appropriate scientific grounds. Harmonization and comparison with other guidelines are discussed. These proposed nontarget plant testing guidelines can serve as a basis for guideline development or modernization for other jurisdictions.
Successive changes in bacterioplankton communities in the river rhine after copper additions
Authors: Tubbing Diny M.J. , Admiraal Wim , Katako Albert 
Published: March 2010

Abstract
The sensitivity of bacterioplankton to copper was analyzed to see whether initial steps in the selection of copper-tolerant life-forms in mixed populations of bacteria were accompanied by changes in basic metabolic parameters. Analysis took place by measuring the incorporation of [3H]thymidine and [3H]leucine, and the hydrolysis of leucyl-β-naphthylamide over a period of 4 d. In acute toxicity tests the radiochemically determined parameters showed the same sensitivities to copper, whereas in the enzyme test the dose-response curve had a much lower slope, indicating less sensitivity. Marked differences were observed in the susceptibility of the different processes after prolonged exposure to copper. Incorporation of [3H]thymidine, [3H]leucine, and proteolytic activity changed substantially during exposure to concentrations as low as 2 to 31 μg Cu L−1. Higher copper concentrations (126-1,000 μg Cu L−1) led in the course of 24 to 48 h to the development of a bacterial community with a higher overall copper tolerance. In winter, these successive events in bacterial populations were observed in the absence of substantial populations of algae or zooplankton. In summer, the metabolic changes in bacterioplankton exposed to copper were strongly affected by the poisoning of other organisms, notably algae, and the subsequent release of organic material. Thus, moderate copper concentrations alter the metabolic profile of bacterial communities, probably as an initial step in the selection of tolerant life-forms.
Bioavailability of polycyclic aromatic hydrocarbons from a historically contaminated sediment core
Authors: Harkey Gail A. , van Hoof Patricia L. , Landrum Peter F. 
Published: March 2010

Abstract
To determine changes in bioavailability of selected polycyclic aromatic hydrocarbons (PAHs) with sediment aging, Lumbriculus variegatus were exposed for 4 weeks to sediment core sections taken from a contaminated lake. Core depths included surficial (0 to 4 cm), 4- to 8-, 12- to 16-, 28- to 32-, and 44- to 48-cm sections deposited from approximately 1899 to 1993, and were known to be historically contaminated with PAHs. Bioaccumulation was maximal at the 12- to 16-cm depth (circa 1967) where sediment PAH concentrations were greatest. Accumulation was generally below detection limits in the 0- to 4-cm depths, even though sediment concentrations of some compounds were comparable to those at the 12- to 16-cm depth where accumulation was great enough to generate accurate kinetics curves. Accumulation peaked at about 96 h, then declined over the remainder of the study for the lower-molecular-weight PAHs. For most higher-molecular-weight PAHs, accumulation peaked at about 2 weeks, then declined only slightly after 4 weeks. The differential bioavailability observed between surficial and at-depth core sections raises questions concerning the adequacy of results generated from toxicity and bioaccumulation tests routinely conducted with surficial sediments.
Lethal body burdens of polar narcotics: Chlorophenols
Authors: van Wezel Annemarie P. , Punte Sophie S. , Opperhuizen Antoon 
Published: March 2010

AbstractThe goal of the present study was to measure in fathead minnow (Pimephales promelas) the lethal body burden (LBB) of three chlorophenols that are known as polar narcotic chemicals. The LBBs of the chlorophenols were compared to LBBs of nonpolar narcotic chemicals to consider if the two classes of narcotic chemicals differ on a body burden level. The LBB of the most acidic chlorophenol was measured at two different levels of pH exposure to determine the influence of the degree of ionization on the magnitude of the LBB. Both n-octanol/water partition coefficients and n-hexane/water partition coefficients of the chlorophenols were determined at different pH levels to consider the influence of ionization on the partition coefficient and to determine the importance of a polar group in the organic phase on the partitioning behaviour. Partitioning to n-octanol and n-hexane was used as input in a model to simulate the equilibrium partitioning between hydrophobic and nonhydrophobic and target and nontarget compartments in the fish.
Use of joint toxic response to define the primary mode of toxic action for diverse industrial organic chemicals
Authors: Broderius Steven J. , Kahl Michael D. , Hoglund Marilynn D. 
Published: March 2010

Abstract
An important aspect of understanding how multiple toxicants jointly act involves defining the primary mode of toxic action for the chemicals of interest. We have explored the use of 96-h acute toxicity tests with juvenile fathead minnows and primarily binary chemical mixtures to define the primary acute mode of toxic action for diverse industrial organic chemicals. Our investigation mainly considered the two special cases of noninteractive joint action known as concentration (simple similar) and response (independent) addition. The different forms of joint toxicity with binary mixtures were graphically illustrated by isoboie diagrams. Designated as the mode of action-specific reference toxicants were 1-octanol, phenol, and 2,4-dimtrophenol. It was observed from binary isobole diagrams that a chemical with a similar primary mode of toxic action to that of a reference toxicant would display a concentration-addition type of joint action with the reference toxicant over the entire mixture ratio range. Dissimilar chemicals with very steep concentration-response curves generally showed an interaction that was less-than-concentration additive, but consistently demonstrated a joint toxicity that was greater than predicted by the response-addition model. The more-than-concentration additive and complex isoboles that are indicative of interactive toxicity were not commonly observed in our experiments.