bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of some factors that may modify the bioavailability of cadmium and lead by Biomphalaria glabrata
Authors: Guerrero Noemí R Verrengia , Nahabedian Daniel E , Wider Eva A 
Published: March 2010

Abstract
Laboratory acute bioassays (t = 96 h) were used to determine the uptake, distribution, and elimination of cadmium and lead by the freshwater gastropod Biomphalaria glabrata. Experiments were conducted on nonpigmented and pigmented organisms separately. The influence of food and different concentrations of humic acids were also investigated. The results showed that, after the treatments, the digestive gland presented the highest level of metal uptake for both elements. Food did not prove to induce significant changes in the pattern of accumulation and distribution within the different tissues. Instead, different concentrations of humic materials modified the pattern of accumulation and distribution of cadmium and lead but in a different way according to the metal. Elimination of cadmium from the soft tissues was considerably slow, presenting a redistribution over the time of depuration. Elimination of lead was faster in the digestive gland and gonads. After all the treatments, no significant differences were observed between nonpigmented and pigmented snails.
Interspecies differences in oxidative stress response and radiocesium concentrations in rodents inhabiting areas highly contaminated by the chornobyl nuclear disaster
Authors: Holloman Kevin A , Dallas Cham E , Jagoe Charles H , Tackett Randall , Kind John A , Rollor Edward A 
Published: March 2010

Abstract
Indicators of oxidative stress response were compared to radionuclide concentrations in rodents from highly contaminated sites around the Chornobyl Nuclear Power Plant, Ukraine, and uncontaminated reference areas. Three rodent species—Apodemus agrarius, Apodemus sylvaticus1, and Clethrionomys glareolus (n = 121)—wecollected from contaminated sites within the 10km exclusion zone surrounding the Chornobyl Nuclear Power Plant and from uncontaminated reference areas in northern Ukraine. Liver samples were analyzed for superoxide dismutase (SOD) and catalase (CAT) activities, and muscle samples were analyzed for radiocesium activity. Superoxide dismutase and catalase activities differed significantly between reference and contaminated groups only for A. agrarius, and activities were lower in contaminated animals relative to those from reference sites. The SOD activity did not differ among species collected in reference areas. Among contaminated groups, A. agrarius had a significantly lower SOD activity than the other two species. Among reference groups, CAT activity for C. glareolus was significantly lower than for the other two species. Very high muscle radiocesium activities (up to 60,000 Bq/g) were found in rodents from contaminated areas, while the references for each species were at or below background. Clethrionomys glareolus had significantly higher muscle radiocesium concentrations than the other species collected at contaminated sites. There were no significant correlations between either SOD or CAT activities and muscle radiocesium concentrations for contaminated or reference animals in any species. There are significant interspecies differences in oxidative enzyme activities in rodents with lifetime exposure at highly radioactive contaminated sites. However, internal radiocesium concentration is not a sensitive predictor of these oxidative stress responses in individuals.
Fate and kinetics of carfentrazone-ethyl herbicide in California, USA, flooded rice fields
Authors: Ngim Kenley K , Crosby Donald G 
Published: March 2010

Abstract
Little is known of the environmental fate of the aryltriazolinone herbicide carfentrazone-ethyl (compound I). Rice field applications of Shark® 40D commercial formulation to duplicate 5.7 m2 rings (119 g a.i./ha) and 464 m2 commercial basins (224 g a.i./ha) produced pseudo–first-order half-lives (t½) of 6.5 to 11.1 h in water and 37.9 to 174 h in sediment. The rapid dissipation from water was due to its hydrolysis to the chloropropionic acid (compound II), which further degraded to its propionic, cinnamic, and benzoic acids. Compound I degraded similarly in soil, but propionic and cinnamic acid levels were higher. Compound I was only weakly adsorbed, but lateral movement of compound II through soil occurred. Laboratory hydrolysis produced quantitative yields of compound II, t½ values of 131 h at pH 7 and 3.36 h at pH 9, and slow dissipation at pH 5 (43% at 830 h). Ultraviolet (UV) irradiation of compound I in pH 7 buffer gave dissipation rates similar to those in dark controls (t½ 113 h vs 128 h), while compound II was comparatively stable to photolysis (t½ 765 h) and also did not volatilize from water. Ester hydrolysis followed by off-site movement of the acid (compound II) account for the dissipation of compound I.
Estimation of water solubility from atom-type electrotopological state indices
Authors: Huuskonen Jarmo 
Published: March 2010

Abstract
Based on the atom-typee ectrotopological state (E-state) indices, a quantitative structure–property relationship model for the prediction of aqueous solubility for a diverse set of 745 organic compounds is presented. The multiple linear regression analysis was used to build the models. A training set of 674 compounds, containing 349 liquids and 325 solids and having a range of aqueous solubility (log S) values from 2.77 to —11.62, was obtained from the literature. For this set, the squared correlation coefficient and standard deviation for a linear model with 31 atom-type E-state indices and three simple correction factors were r2 = 0.94 and s = 0.58 (log units), respectively. The corresponding statistics for the test sets not included in the training set were, for a set of 50 pesticides, r2 = 0.79 and s = 0.81 and, for a set of 21 drug and pesticide compounds, r2 = 0.83 and s = 0.84, respectively. The contribution of melting points was also evaluated. The use of melting point increased the accuracy of the models in the fit of the training set but not in the prediction of the test sets. Hence, the proposed method offers fast and accurate estimation of aqueous solubility of organic compounds using atom-type E-state indices without the need of any experimental parameters like the melting points.
Theoretical framework for the distribution of trace metals among the operationally defined speciation phases of a sediment
Authors: Nome René A. , Mendiguchía-Martínez Carolina , Nome Faruk , Fiedler Haidi D 
Published: March 2010

Abstract
The use of a model based on Langmuir's isotherm to evaluate the metal associated with separate geochemical phases of a sediment is proposed and its validity tested with sediments of certified composition. The model takes into account a standard procedure for a certified reference material (CRM601), which defines, experimentally, a set of sequential extractions that divide the sediment into four operational fractions. The derived equations allow the treatment of data from sediment of Flumendosa Lake, Italy, and certified material CRM601 and also allow the computation of corrected concentrations, i.e., the metal affinities for each fraction. Experimental values for Ni show its low sensitivity and an equal distribution among different phases, which suggests a similar adsorption mechanism in all cases. In the case of Cd, the corrected concentration in the Fe/Mn oxide phase is nine times higher than for the residual fraction. For sediment of the Bèsos River, Spain, results show the percentage distribution of Ni over different fractions. Affinity values for Ni on a Flumendosa Lake sediment have also been calculated. The present model is simple to apply and shows satisfactory agreement with experimental data.
Bioaccumulation of polycyclic aromatic compounds: 1. Bioconcentration in two marine species and in semipermeable membrane devices during chronic exposure to dispersed crude oil
Authors: Baussant Thierry , Sanni Steinar , Jonsson Grete , Skadsheim Arnfinn , Børseth Jan Fredrik 
Published: March 2010

Abstract
Assessing the fate in marine biota of hydrocarbons derived from oil particles that are discharged during exploration and production is of relevant environmental concern. However, a rather complex experimental setup is required to carry out such investigations. In this study, a sophisticated tool, the continuous-flow system (CFS), was used to mimic dispersed oil exposure to marine biota. Polycyclic aromatic hydrocarbon (PAH) uptake was studied in two species, the blue mussel Mytilus edulis and juvenile of the turbot Scophthalmus maximus, and in semipermeable membrane devices (SPMD) exposed to crude oil dispersed in a flow-through system. After an exposure period of 8 to 21 d, elimination in organisms and devices was analyzed for 9 to 10 d following transfer to PAH-free seawater. Principal component analysis (PCA) revealed different PAH patterns. In mussel and SPMD, the PAH profiles were very close to that analyzed in seawater. Slight differences were, however, indicated for large molecules with log Kow above six. Nonachievement of steady-state concentration and bioavailability of PAH in oil droplets may account for these differences. The PAH composition in fish revealed only congeners with two to three aromatic rings. A combination of bioavailability and efficient metabolism of the larger PAH molecules may explain this pattern. The CFS made possible a better understanding of some critical factors governing bioconcentration in marine biota from dispersed oil. Yet the results illustrate that uptake of PAH from exposure to oil particles is complex and that different species may bioconcentrate different molecules depending on factors like life style and metabolic capability to degrade the potential harmful substances. Hence, risk assessment of the actual impact of discharges to marine biota should consider these essential biological and ecological factors.
Loss rates of polycyclic aromatic hydrocarbons from sediment and deposit-feeder fecal pellets
Authors: Horng Ching-Yi , Taghon Gary L 
Published: March 2010

Abstract
Deposit feeders modify sediment by aggregating individual particles into fecal pellets. Loss of contaminants may be either more (enhanced bacterial degradation) or less (hindered diffusion and desorption) rapid for sediment incorporated into pellets. We studied the loss of 10 polycyclic aromatic hydrocarbons (PAHs) from historically contaminated estuarine sediment and the same sediment after it had been pelletized by Capitella sp. I, a polychaete worm typically found in disturbed environments. Fecal pellets initially had higher concentrations of organic carbon and PAHs (enrichment factors 1.03–1.21) due to selective feeding. Over 60 d, desorption of PAHs was minimal, with an average loss of 4 to 5%. Biodegradation accounted for an additional 28% loss. A two-component model fit the data well and indicated that the slowly desorbing fraction was close to one for all PAHs. For low molecular weight PAHs, biodegradation rate constants were greater than desorption rate constants; for high molecular weight PAHs, the opposite was found. Desorption rate constants were similar for fecal pellets (0.0002–0.037/d) and sediment (0.0002–0.031/d). Biodegradation rate constants were also similar for fecal pellets (0.0006–0.022/d) and sediment (0.0002–0.018/d). Thus, incorporation of sediment into robust fecal pellets (half-life on the order of decades) did not affect the loss rates of PAHs.
Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 2. Toxicity of aircraft and runway deicers
Authors: Corsi Steven R , Hall David W , Geis Steven W 
Published: March 2010

Abstract
Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox® were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased.
The effect of thiolate organic compounds on methylmercury accumulation and redistribution in sheepshead minnows, Cyprinodon variegatus
Authors: Leaner Joy Jacqueline , Mason Robert Peter 
Published: March 2010

Abstract
Methylmercury (CH3Hg(II)) was measured in various tissues and whole body of sheepshead minnows, Cyprinodon variegatus, following exposure to 100 ng/L methylmercury chloride (CH3HgCl) alone or in combination with one of the organic compounds cysteine (CH3Hg-Cys), thiourea (CH3Hg-Thu), or thioglycolate (CH3Hg-Thg). Overall, the CH3Hg(II) concentration in sheepshead minnows in all the treatments increased with time and was significantly different from the unspiked controls after 24 h. Addition of the organic compounds increased the bioavailability of CH3Hg(II) in the whole body of the fish after 72 h. In particular, the CH3Hg(II) concentration after CH3Hg-Thg and CH3Hg-Thu exposure was, respectively, approximately 1.3- and 1.6- fold higher than with CH3HgCl exposure. A composite of the CH3Hg(II) concentrations in the visceral organs (gill, liver, and intestine) highlighted the effect of the organic compounds, where concentrations in all mercury-thiolate treatments were significantly higher than CH3HgCl alone after 72 h. The most dramatic changes in the different tissues measured were observed in the liver, where the CH3Hg(II) concentrations in the sulfur treatments were significantly higher than the CH3HgCl treatment after 72 h. The results of this study suggest that the CH3Hg-thiolate complexes were bioavailable to sheepshead minnows and effectively induced CH3Hg(II) uptake in tissues at environmentally realistic CH3HgCl concentrations.
Behavioral effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus
Authors: Ding Jing , Drewes Charles D , Hsu Walter H. 
Published: March 2010

Abstract
Ivermectin is a potent antiparasitic drug against nematode and arthropod parasites. In this study, we examined the lethal and sublethal effects of ivermectin in a freshwater oligochaete, Lumbriculus variegatus. The median lethal concentration (LC50) at 72 h after ivermectin exposure was 560 nM. Sublethal endpoints focused on several stimulus-evoked locomotor behaviors: escape reflexes controlled by giant interneuron pathways, swimming and reversal, and crawling. Swimming, reversal, and crawling are controlled by nongiant interneuron pathways. Ivermectin inhibited swimming, reversal, crawling frequency, and crawling speed in a time- and concentration-dependent manner with a mean inhibitory concentration (IC50) at 3 h of 1.1, 16, 91, and 51nM, respectively. Ivermectin at 0.3 nM also significantly decreased the frequency of helical swimming waves. Picrotoxin, a Cl− channel blocker, antagonized the ivermectin-induced decrease in swimming frequency, crawling frequency, and crawling speed. There were no adverse effects on escape reflex 3 h after exposure to 300 nM ivermectin. Electrophysiological recordings showed that ivermectin had no effects on the conduction velocity of giant fiber systems. The results indicated that locomotor behaviors controlled by nongiant locomotor pathways were more sensitive to ivermectin than pathways controlled by giant interneurons and that Cl− channels may be involved in mediating ivermectin's inhibitory effects.
Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 4. The influence of salt speciation, soil type, and sewage sludge on toxicity using the collembolanFolsomia fimetariaand the earthwormAporrectodea caliginosaas test organisms
Authors: Holmstrup Martin , Krogh Paul Henning , Løkke Hans , de Wolf Watze , Marshall Stuart , Fox Kay 
Published: March 2010

AbstractSewage sludge applied to agricultural soils often contains linear alkylbenzene sulfonates (LAS) in the range of 1 to 10 g/kg dry weight, and their toxicity to relevant soil organisms should, therefore, be assessed to ensure safe use of sewage sludge as a fertilizer. Studies of LAS toxicity to soil organisms are few, and to our knowledge, factors that may influence the toxicity in the field have not been studied in detail. In this paper, we report on the influence of speciation of LAS in the test solution added to soil (soluble Na-LAS vs poorly soluble Ca-LAS or Mg-LAS), the influence of soil type, and the modifying effects of sludge amendment on the toxicity of LAS. These issues were investigated using reproduction of Collembola and growth of juvenile earthworms as test parameters. Speciation of the LAS added to test soil did not have any influence on toxicity for any of the test species. Likewise, in three different agricultural soils (sand, loam, and clay), we found almost equal toxicities. The LAS added to test soil in a sludge—water suspension was equally toxic as when it was added in an aqueous solution. However, anaerobic incubation for 7 and 14 d of the LAS—sludge suspension (with no decay of LAS) caused the toxicity to increase almost threefold in both collembolan and earthworm. The relationships between soil constituents, bioavailability, and toxicity are also discussed.
Kinetics, dose-response, excretion, and toxicity of methylmercury in free-living Cory's shearwater chicks
Authors: Monteiro Luis R , Furness Robert W 
Published: March 2010

Abstract
Methylmercury (MHg) kinetics, dose–response, excretion, and toxicity were experimentally evaluated and compared between small (one to two weeks old) and large (six to seven weeks old), free-living Cory's shearwater chicks. The half-time for the terminal elimination phase of MHg in blood (5.7 d) and the average percentage of ingested MHg deposited in the blood volume (12%) were independent of the age at exposure. Therefore, these data were employed to derive a relationship between steady-state blood concentrations and dietary intake of MHg in bird chicks. Plumage:blood ratios were independent of dose and could be used as partition coefficients. Dose–response relationships in plumage and blood were linear over the wide range of exposures employed. Blood dose–responses of MHg in small and large chicks were similar. Excretion percentages into the final plumage varied between 42 and 60% of intake. The body condition of experimental chicks did not indicate sublethal toxicity of the doses administered; hence, the exposure levels provide maximum avian no-observed-adverse-effect levels for external symptoms in wild seabird chicks.
Identification and quantitation method for nonylphenol and lower oligomer nonylphenol ethoxylates in fish tissues
Authors: Snyder Shane A , Keith Timothy L , Naylor Carter G , Staples Charles A , Giesy John P 
Published: March 2010

Abstract
Substantial research is currently focused on the toxicological effects of alkylphenol ethoxylates (APEs) and alkylphenols (APs) on aquatic animals. Considerable data are available on the concentrations of APEs and APs in river systems in the United States; however, few if any data are available on the tissue concentrations of fish living in these rivers. A reliable method for the analysis of nonylphenol (NP) and lower oligomer nonylphenol ethoxylates (NPE1–3) in fish tissues has been developed. Nonylphenol and NPE1–3 were extracted from fish tissues using extractive steam distillation. Normal phase high-performance liquid chromatography (HLPC) was used as a cleanup step prior to analysis by gas chromatography with mass selective detection (GC/MSD) using selected ion monitoring. Optimization of this technique resulted in consistent recoveries in excess of 70%, with the exception of NPE3 (17%). Method detection limits (MDLs) and limits of quantitation using the technique range from 3 to 20 and 5 to 29 ng/g wet weight, respectively. Nonylphenol and NPE1 were detected in subsamples (n = 6) of a single common carp captured in the Las Vegas Bay of Lake Mead (NV, USA) at average concentrations of 184 ± 4 ng/g and 242 ± 9 wet weight, respectively. Nonylphenol ethoxylates2&3 were not detected in the carp collected at Lake Mead.
Identification of hydroxylamino-dinitroso-1,3,5-triazine as a transient intermediate formed during the anaerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine
Authors: Adrian Neal R , Chow Teresa 
Published: March 2010

Abstract
The metabolic fate of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in a mixed culture incubated under methanogenic conditions was studied. Analysis by high-performance liquid chromatography (HPLC) confirmed the loss of RDX and the formation of mono-, di-, and trinitroso-RDX as transient biodegradation intermediates. An additional peak observed in the HPLC chromatograms was identified by liquid chromatography–mass spectrometry as hydroxylamino-dinitroso-1,3,5-triazine. This is the firstreport identifying hydroxylamino-dinitroso-1,3,5-triazine as a transient intermediate produced during the anaerobic biodegradation of RDX.
Effects of terbutryn on aufwuchs and Lumbriculus variegatus in artificial indoor streams
Authors: Brust Kristin , Licht Oliver , Hultsch Veit , Jungmann Dirk , Nagel Roland 
Published: March 2010

Abstract
The effects of the herbicide terbutryn on a simple lotic food web were investigated during a 72-d exposure period in five artificial indoor streams in a greenhouse. The model compound terbutryn, an s-triazine and an inhibitor of photosynthesis, was applied once in each stream at nominal concentrations of 0.6, 6, 60, or 600 μg/L. Terbutryn concentrations in the water were analyzed by gas chromatography/mass spectrometry, and an overall time to 50% dissipation (DT50) of 28 d was calculated. The development of aufwuchs and the population growth and development of the oligochaete Lumbriculus variegatus were investigated. We determined that terbutryn was toxic to L. variegatus at 23.7 mg/L (96-h median lethal concentration [LC50]) and 16.5 mg/L (96-h median effective concentration [EC50]) in static acute toxicity tests. Terbutryn decreased aufwuchs production at 0.6 μg/L in the experimental streams. Population growth of L. variegatus was decreased by 50% at 6 μg/L. The effect of terbutryn on the aufwuchs was a direct effect of decreases in the periphyton. However, the effects on L. variegatus were an indirect effect of terbutryn as a consequence of decrease in the aufwuchs food source and occurred at three-orders-of-magnitude-lower concentrations of terbutryn than the acute toxicity effects. Our study demonstrates the utility of indoor lotic microcosm studies for evaluating both direct and indirect effects of contaminants on aquatic ecosystems.