bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fate and disposition of diflubenzuron in rice fields
Authors: Mabury Scott A. , Crosby Donald G. 
Published: March 2010

Abstract
Laboratory and field investigations were undertaken to determine the fate, disposition, and persistence of the insecticide diflubenzuron in California rice culture. Water solubility was similar in distilled/deionized water (88.8 ± 4.0 μg/L) and rice field water (92.6 ± 3.5 μg/L), while the measured Henry's law constant was 2.34 ± 0.02 × 10−1 Pa.m3/mole. Diflubenzuron was rapidly photodegraded in field water primarily to the more stable chlorophenylurea and difluorobenzoic acid; field water photolysate was equally toxic to Daphnia magna as pure insecticide solutions. Applications to experimental rice field plots resulted in rapid dissipation of diflubenzuron (half-life 27.3 h), nonpersistent sediment residues, and significant partitioning into the surface microlayer.
Reductive dechlorination of chlorobenzenes in surfactant-amended sediment slurries
Authors: Van Hoof Patricia L. , Jafvert Chad T. 
Published: March 2010

Abstract
Microbial anaerobic dechlorination of hexachlorobenzene (HCB) was examined in sediment slurries amended with two classes of nonionic surfactant, polyoxyethylene (POE) sorbitan fatty acid esters (Tweens) and POE alcohols (Brijs). The rationale for surfactant addition was to increase the bioavailability of highly sorbed organic pollutants to degrading microorganisms by enhancing their solubility. The solubility of HCB was initially enhanced via micellar partitioning; however, primary degradation of most surfactants occurred within 10 d. Dechlorination activity was significantly reduced at POE alcohol concentrations above the critical micelle concentration (cmc), with or without the occurrence of surfactant degradation. Tween 80 decreased HCB dechlorination at concentrations significantly above the cmc (1,500–5,000 mg/L). At concentrations closer to the cmc (300–1,200 mg/L), Tween 80 increased dechlorination rate constants four- to fivefold in acclimated slurries. Additions of Tween 80 at or below the cmc (3, 30, 300, and 911 mg/L) stimulated dechlorination activity in unacclimated slurries that exhibited very little activity in unamended controls. An average of 89% of HCB was dechlorinated after 90 d, compared to 20% in unamended sediments. No effect was observed for POE alcohols at these sub-cmc levels. The lack of a stimulated response for the POE alcohols suggests that Tween 80 may not be acting simply as a source of carbon or energy.
Measuring bioavailable copper using anodic stripping voltammetry
Authors: Deaver Emily , Rodgers John H. 
Published: March 2010

AbstractSince speciation can affect bioavailability and toxicity of copper in aquatic systems, accurate predictions of effects of bioavailable forms require detection and/or measurement of these forms. To develop an approach for measurement of bioavailable copper, a copper sulfate solution (CuSO4·3Cu(OH)2·H2O) was used in 10-d aqueous and sediment toxicity tests with Hyalella azteca Saussure. These tests encompassed ranges of pH (6.5 to 8.1), alkalinity (10 to 70 mg/L as CaCO3), hardness (10 to 70 mg/L as CaCO3), and conductivity (30 to 300 μmho/cm). Changes in copper speciation were measured using atomic absorption spectroscopy (AA) for dissolved copper and differential pulse anodic stripping voltammetry (DPASV) for labile copper, and concentrations were evaluated relative to amphipod survival. Ten-day LC50s based on AA-measured aqueous copper concentrations ranged from 42 to 142 μg Cu/L, and LC50s based on DPASV-measured copper concentrations ranged from 17.4 to 24.8 μg Cu/L. In 10-d tests using copper-amended sediments with diverse characteristics and AA-measured copper concentrations spanning an order of magnitude, total copper concentrations were not predictive of sediment toxicity, but H. azteca survival was explained by DPASV measurements that varied by ≤4%. In order to make defensible estimates of the potential risk of metals in sediments or water, it is essential to identify the fraction of total metal that is bioavailable. In these experiments, DPASV was useful for measuring bioavailable copper in aqueous and sediment tests with H. azteca.
Spermiotoxicity and embryotoxicity of heavy metals in the echinoid Paracentrotus lividus
Authors: Warnau Michel , Temara Ali , Jangoux Michel , Dubois Philippe , Iaccarino Mario , De Biase Antonella , Pagano Giovanni 
Published: March 2010

Abstract
Spermio- and embryotoxicities of Cu, Ag, Cd, and Hg were investigated in Paracentrotus lividus, the dominant echinoid species of the Mediterranean. Spermiotoxicity was studied by assessing the effects of sperm exposure on fertilization rate (FR) as well as on the induction of transmissible damages to the offspring. Embryotoxicity was studied by assessing developmental defects in larvae exposed to the tested metals throughout their development. Sperm exposures resulted in significant decreases of FR, depending on both metal concentration and duration of the exposure. Lowest spermiotoxic concentrations recorded when sperm were exposed for 75 min to the metals were 10−7 M Hg(II), 10−6 M Ag(I), 10−5 M Cu(II), and 10−5 M Cd(II). Tested metals did not exert any transmissible damage to spermatozoa that could result in larval malformations in the offspring, even for concentrations that dramatically reduced FR. Single-element exposures of embryos for 72 h resulted in developmental defects whose occurrence and severity showed a steep dose dependence, indicating that once a threshold is reached, any further increase in toxicant concentration rapidly enhances the impairment of target function(s). Those observations suggest the involvement of a saturable protective mechanism. Lowest observed embryotoxic concentrations of the metals were 10−7 M Hg(II), 2.5 × 10−7 M Ag(I), 5 × 10−7 M Cu(II), and 10−5 M Cd(II) and are in the range of concentrations reported in heavily polluted marine environments. Thus, the possibility of impairment of echinoid development actually exists in metal-contaminated marine environments, possibly threatening echinoid populations in those environments.
Reduced biodegradability of desorption-resistant fractions of polycyclic aromatic hydrocarbons in soil and aquifer solids
Authors: White Jason C. , Alexander Martin 
Published: March 2010

Abstract
Less of the desorption-resistant fractions of phenanthrene and naphthalene than freshly added phenanthrene and naphthalene was mineralized in columns of aquifer solids, loam, or muck. Slurrying columns of hydrocarbon-amended aquifer solids, loam, or muck enhanced the rate and extent of mineralization of desorption-resistant phenanthrene and naphthalene, but degradation was still less than in slurries amended with fresh compound. A substantial portion of the desorption-resistant compound remained undegraded in the slurry. A surfactant and methanol increased the mineralization of resistant phenanthrene in slurries of loam. A mixed culture of microorganisms enriched on desorption-resistant phenanthrene degraded twice as much of this fraction of compound as a pseudomonad. We suggest that predictions of the environmental fate of toxic chemicals require information on the biodegradability of the fraction of a compound that is resistant to desorption.
Distributions of key exposure factors controlling the uptake of xenobiotic chemicals in an estuarine food web
Authors: Iannuzzi Timothy J. , Harrington Natalie W. , Shear Nadine M. , Curry Cynthia L. , Carlson-Lynch Heather , Henning Miranda H. , Su Steave H. , Rabbe David E. 
Published: March 2010

Abstract
A critical evaluation of literature on the behavior, physiology, and ecology of common estuarine organisms was conducted in an attempt to develop probabilistic distributions for those variables that influence the uptake of xenobiotic chemicals from sediments, water, and food sources. The ranges, central tendencies, and distributions of several key parameter values were identified for dominant organisms from various trophic levels, including the polychaete Nereis virens, mummichog (Fundulus heteroclitus), blue crab (Callinectes sapidus), and striped bass (Morone saxatilis). The exposure factors of interest included ingestion rate for various food sources, growth rate, respiration rate, excretion rate, body weight, wet/dry weight ratio, lipid content, chemical assimilation efficiency, and food assimilation efficiency. These exposure factors are critical to the execution of mechanistic food web models, which, when properly calibrated, can be used to estimate tissue concentrations of nonionic chemicals in aquatic organisms based on knowledge of the bioenergetics and feeding interactions within a food web and the sediment and water concentrations of chemicals. In this article we describe the use of distributions for various exposure factors in the context of a mechanistic bioaccumulation model that is amenable to probabilistic analyses for multiple organisms within a food web. A case study is provided which compares the estimated versus measured concentrations of five polychlorinated biphenyl (PCB) congeners in a representative food web from the tidal portion of the Passaic River, New Jersey, USA. The results suggest that the model is accurate within an order of magnitude or less in estimating the bioaccumulation of PCBs in this food web without calibration. The results of a model sensitivity analysis suggest that the input parameters which most influence the output of the model are both chemical and organism specific.
Characteristics of butyltin accumulation and its biomagnification in steller sea lion (Eumetopias jubatus)
Authors: Kim Gi Beum , Tanabe Shinsuke , Tatsukawa Ryo , Loughlin Thomas R. , Shimazaki Kenji 
Published: March 2010

Abstract
The present study was conducted to examine sex difference, age, and temporal trends of butyltin accumulation and its biomagnification in Steller sea lion (Eumetopias jubatus) collected from Alaska, USA, during 1976–1985 and from Hokkaido, Japan, during 1994–1995. Average concentration of total butyltin compounds (ΣBTs) in the liver of Steller sea lion from Alaska (19 ng/g wet weight) was much lower than those from western and eastern Hokkaido, Japan (150 and 220 ng/g), respectively. This result suggests that Japanese coastal waters are contaminated with BTs in comparison with those of Alaska. In most samples, dibutyltin (DBT) residues were retained at higher levels than tributyltin (TBT), suggesting the degradation of TBT to DBT in the liver. Sex difference and age-dependent accumulation of BTs residues were not found in Steller sea lion. Similarly, no prominent temporal trend in BT concentrations was observed between 1976 and 1985. Nevertheless, the annual consumption of organotin compound was doubled in the United States during the same period. These results suggest that the butyltin compounds are degraded faster than the intake from diet in Steller sea lion. The biomagnification factor of BTs in Steller sea lion was low (0.15–4.6; mean, 0.6), indicating that this animal is unlikely to magnify BTs due to rapid degradation and excretion.
Evaluation of metal/acid-volatile sulfide relationships in the prediction of metal bioaccumulation by benthic macroinvertebrates
Authors: Ankley Gerald T. 
Published: March 2010

AbstractRecent studies have demonstrated that the toxicity of divalent cationic metals (cadmium, copper, lead, nickel, and zinc) in sediments can be controlled through binding to acid-volatile sulfide (AVS). When the molar concentration of AVS exceeds that of the metals (i.e., the metal/AVS ratio is less than unity), they exist predominantly as insoluble metal sulfides, which presumably are not biologically available. Thus, at metal/AVS ratios less than 1, toxicity of sediment-associated metals to benthic macroin-vertebrates has not been observed. However, bioaccumulation may provide a more direct assessment of contaminant bioavailability than the presence or absence of toxicity. The purpose of this report is to comprehensively review available literature on metal bioaccumulation versus sediment metal/AVS relationships to further examine the tenet that AVS controls metal bioavailability. In all, 12 studies were evaluated; these ranged from short-term (10-d) laboratory experiments with metal-spiked or field-collected sediments containing cadmium, copper, lead, nickel, and/or zinc to long-term (&gt; 1-year) field studies with sediments spiked with cadmium or zinc. Test organisms included mollusks, oligochaetes, polychaetes, amphipods, and midges. The preponderance of studies indicated reduced accumulation of metals at sediment metal/AVS ratios of less than 1. However, there were exceptions to this general observation, two of which occurred in short-term laboratory experiments with cadmium- or nickel-spiked sediments. In these studies there appeared to be a linear accumulation of metals with increasing sediment metal concentrations irrespective of the metal/AVS ratio. Although there is experimental evidence suggesting that significant bioaccumulation of metals does not occur when there is sufficient AVS available to bind them, the existence of at least some data to the contrary indicates the need for further research relative to factors controlling the bioaccumulation of metals from sediments.
A model of the oxidation of iron and cadmium sulfide in sediments
Authors: Di Toro Dominic M. , Mahony John D. , Hansen David J. , Berry Walter J. 
Published: March 2010

AbstractA model is presented for the temporal and vertical variation of acid-volatile sulfide (AVS), simultaneously extracted cadmium (SEMcd), and cadmium interstitial water concentration in sediments. The model is based on the one-dimensional advective-dispersive mass balance equation. Transport by particle and pore-water mixing is considered. The state variables include the components of AVS and SEMcd, namely iron sulfide (FeS) and cadmium sulfide (CdS), and sorbed + pore-water cadmium (CdT). In addition, particulate organic carbon (POC), iron oxyhydroxide, and dissolved oxygen are explicitly modeled. The oxidation, displacement, and partitioning reactions that are sources and sinks of the state variables are included. The model is applied to three experimental data sets. Two of these employed marine sediments with typical organic carbon and AVS concentrations. The third employed a freshwater sediment with a high POC and low AVS. The calibration produced similar partitioning parameters on an organic carbon basis for both sediments. However, the oxidation and partitioning behavior of the FeS in the low AVS freshwater sediment was distinctly different from the high AVS cases. The model successfully reproduces the major features of the experimental data: the progressive decrease in AVS and SEMcd, and an increase in the SEMcd to AVS ratio in the surface layers. It is less successful in reproducing the pore-water cadmium concentrations.
Partitioning of metals to sediment organic carbon
Authors: Mahony John D. , Di Toro Dominic M. , Gonzalez Adrian M. , Curto Mark , Dilg Maureen , De Rosa Laurie D. , Sparrow Leslie A. 
Published: March 2010

AbstractThe partition coefficients and sorption capacities for cadmium, copper, and lead in freshwater sediments are derived from fitting a Langmuir isotherm to data from 14 sediments. The metal activity in the solution phase was measured using specific ion electrodes. The metal sorption due to acid-volatile sulfide was subtracted from the total sorbed metal to produce the metal bound to other sediment phases. Organic carbon normalized isotherms provide a reasonable representation of the metal sorption. Partition coefficients and capacities are calculated for pH = 6, 7, and 8 (for Cd). The organic carbon normalized isotherm parameters for the sediments are compared to those reported for soils and sludges. The comparisons for cadmium exhibit differences for which no ready explanations are available. For copper and lead, however, the differences can be attributed to the use of specific ion electrodes for measuring metal activity in the sediment experiments. The cadmium sediment partition coefficients contribute a small increment to the sediment quality criteria. For copper and lead, however, the additional binding to sediment organic carbon is significant and can amount to 1 to 10 and 10 to 100 μmol/g dry weight for lead and copper, respectively, depending on the organic carbon concentration of the sediment.
Estimation of partition coefficients for five trace metals in sandy sediments and application to sediment quality criteria
Authors: Hassan S.M. , Garrison A.W. , Allen H.E. , Di Toro D.M. , Ankley G.T. 
Published: March 2010

Abstract
Six low-capacity natural adsorbents-were identified for the five metal cations (cadmium, copper, nickel, lead, and zinc) for which the U.S. Environmental Protection Agency is developing sediment quality criteria (SQC). The adsorbents were commercial sea sand and chromatographic sand (both from natural sources) and four sandy sediments collected from different parts of the continental United States. Batch adsorption experiments were conducted for each sediment with a mixture of the five cations at low concentrations (from about 15 to 700 μg/L) using a 48-h equilibration time. The distribution coefficients (Kds) were calculated using the initial linear segment of the plotted adsorption isotherms; selection of the linear segment involved repetitive regression analysis of selected data points. Chromatographic sand at pH 3.7 showed the lowest adsorption capacity for all the metal cations. An increase in pH of the medium generally resulted in a higher Kd, whereas an increase in ionic strength resulted in a lower Kd Chromatographic sand, especially at low natural pH levels, may serve as a limiting adsorbent or a benchmark for maximum pore-water concentrations for these five metal cations because its associated pore water would contain higher levels of the cations than other sediments. These measured Kds, which are expected to be minimum values for natural sediments, were applied to screen sediment samples for SQC. An equation that can predict the Kd for each of the five metals for sandy sediments at neutral and lower pH levels was derived from the regression of the measured Kds against the pH of the six sediments used in this study. This equation was tested with a data set from Lake Michigan sediment samples. Porewater metal concentrations calculated from the predicted Kd values were used to predict whether a sediment would pass SQC in terms of predicted interstitial water criteria toxic units; 16 of 38 of these sediments were predicted not to exceed proposed SQC for metals.
Estimation of polycyclic aromatic hydrocarbon concentrations in the water column based on tissue residues in mussels and salmon: An equilibrium partitioning approach
Authors: Neff Jerry M. , Burns William A. 
Published: March 2010

Abstract
Equilibrium partitioning was used to estimate concentrations of dissolved polycyclic aromatic hydrocarbons (PAHs) in the water column from PAH residues in tissues of mussels and juvenile pink salmon collected from coastal marine waters affected by the Exxon Valdez oil spill. Estimated concentrations were within factors of 2 to 5 for fish and 5 to 10 for mussels of average total dissolved and particulate PAHs measured in concurrent water samples. Temporal trends of estimated and measured water‒column PAH concentrations were comparable. Water‒column PAH concentrations estimated from residues in tissues of mussels (Mytilus trossulus) were higher than estimates based on residues in tissues of juvenile pink salmon (Oncorhynchus gorbuscha). Possible reasons for this difference include seasonal variations in mussel lipid content, differences in PAH uptake and depuration rates between fish and mussels, differences in how fish and mussels interact with particulate oil, and possible short exposure times for juvenile pink salmon. All of these factors may play a role. In any event, estimates of dissolved PAHs in the water column, based on PAH residues in either fish or mussel tissue, confirm that PAH concentrations generally did not exceed water quality standards for protection of marine life.
Action of insecticides on the cellular immune reaction of Drosophila melanogaster against the parasitoid Leptopilina boulardi
Authors: Delpuech Jean-Marie , Frey Françoise , Carton Yves 
Published: March 2010

Abstract
Drosophila larvae infested by endoparasitoids can survive the infestation by an immune reaction leading to the encapsulation and destruction of parasitoid eggs. Conversely, parasitoids can escape the encapsulation by inhibiting this immune reaction. These processes could be influenced by exposure to pesticides, so an experiment was designed to investigate this possibility. Two strains of Drosophila melanogaster Meigen were tested, one with a high capacity for encapsulation (reactive strain) and the other with a very low capacity for encapsulation (nonreactive strain). We compared their immune reaction capacity after infestation when reared on a medium containing or not containing an LD30 of insecticide. Six different insecticides were tested. Two appeared to modify the effectiveness of the immune reaction. When the reactive strain was tested, dieldrin decreased the success of the immune reaction by 25%, and endosulfan, by 23%. Endosulfan also decreased the encapsulation rate of this strain by 26%. With the nonreactive strain no effect was observed regardless of insecticide. The possible causes of these weakening of encapsulation ability and their consequences on the evolution of these species are discussed.
Purification and immunochemical detection of β-naphthoflavone-and phenobarbital-induced avian cytochrome P450 enzymes
Authors: Brown Randal L. , Levi Patricia E. , Hodgson Ernest , Melancon Mark J. 
Published: March 2010

Abstract
Livers from mallards (Anas platyrhynchos) were treated with either β-naphthoflavone (50 mg/kg) or phenobarbital (70 mg/kg). Purification of induced hepatic cytochrome P450 was accomplished using both DEAE and hydroxyapatite columns, as well as sodium dodecyl sulfate polyacrylamide gel electrophoresis separation. Polyclonal antibodies to these proteins were then produced in young male New Zealand White rabbits. β-Naphthoflavone (βNF)- and phenobarbital (PB)-treated red-winged blackbird, screech owl, European starling, and lesser scaup liver microsomes were analyzed in western blots for species cross-reactivity. Although all four of these avian species exhibited cross-reactivity with antibodies to βNF-induced mallard P450, all but the lesser scaup revealed a protein of higher molecular weight than that of the βNF-induced mallard. In addition, only the lesser scaup exhibited cross-reactivity with the anti-PB-induced mallard P450 antibodies.