bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid mineralization of the endocrine-disrupting chemical 4-nonylphenol in soil
Authors: Topp Edward , Starratt Alvin 
Published: March 2010

Abstract
The persistence of the xenoestrogenic compound 4-nonylphenol in agricultural, noncultivated temperate, and Arctic soils was assessed in laboratory microcosm incubations. At 30°C, [ring-U-14C]4-nonylphenol was rapidly mineralized without a lag in six soils tested. A sandy loam agricultural soil was chosen for more detailed study. The 4-nonylphenol mineralization did not occur in autoclaved soil. The response of 4-nonylphenol mineralization to variation in temperature and moisture content was consistent with an aerobic biological mechanism of degradation. Mineralization of [ring-U-14C]4-nonylphenol was rapid in the concentration range of 1 to 250 mg/kg soil. Sludge solids did not inhibit 4-nonylphenol mineralization, although sewage sludge at high concentrations was inhibitory, apparently because of high biological oxygen demand. Gas chromatographic-mass spectrometric analyses of extracts prepared from soil incubated with commercial nonylphenol indicated that all detectable isomers were degraded. In summary, these results indicate that microorganisms that can metabolize 4-nonylphenol are found in a wide variety of soils, including two originating from the Canadian Far North, which presumably have not been exposed anthropogenically to this chemical. We conclude that 4-nonylphenol should be generally biodegradable in well-aerated arable soils.
In vitro kinetics of hepatic glutathione s-transferase conjugation in largemouth bass and brown bullheads
Authors: Allagher Evan P. G , Sheehy Karen M , Lame Michael W , Segall Henry J 
Published: March 2010

Abstract
The kinetics of glutathione S-transferase (GST) catalysis were investigated in largemouth bass (Micropterus salmoides) and brown bullheads (Amerius nebulosus), two freshwater fish species found in a variety of polluted waterways in the eastern United States. The initial rates of hepatic GST activity toward four GST substrates, including 1-chloro-2,4-dinitrobenzene, ethacrynic acid, Δ5-androstene-17-dione, and nitrobutyl chloride, were significantly higher in brown bullheads than in largemouth bass. Hepatic GST activity toward 1,2-dichloro-4-nitrobenzene, a μ-class GST substrate in rodents, was not detectable in either species. Liver cytosolic GSTs were more efficient in bullheads than in bass at catalyzing 1-chloro-2,4-dinitrobenzene-reduced glutathione (CDNB-GSH) conjugation over a broad range of electrophile (CDNB) concentrations, including those representative of environmental exposure. In contrast, largemouth bass maintained higher ambient concentrations of GSH, the nucleophilic cofactor for GST-mediated conjugation, than brown bullheads. Biphasic kinetics for GST-CDNB conjugation under conditions of variable GSH concentration were apparent in Eadie-Hofstee plots of the kinetic data, suggesting the presence of at least two hepatic GST isozymes with markedly different Km values for GSH in both species. The GST-CDNB reaction rate data obtained under conditions of variable GSH were well fitted (R2 = 0.999) by the two-enzyme Michaelis-Menten equation. In addition, Western blotting experiments confirmed the presence of two different hepatic GST-like proteins in both largemouth bass and brown bullhead liver. Collectively, these findings indicate that largemouth bass and brown bullhead GSTs catalyze the conjugation of structurally diverse, class-specific GST substrates, and that brown bullheads exhibit higher initial rates of GST activity than largemouth bass. The relatively higher rates of in vitro liver GST activity at the low substrate concentrations relevant to environmental exposure is expected to protect brown bullheads from the toxic effects of sediment-associated electrophilic chemicals. The somewhat lower rates of GST activity in largemouth bass liver compared with brown bullhead liver, however, may be offset by maintenance of higher ambient hepatic GSH concentrations in largemouth bass.
Time-integrated, flux-based monitoring using semipermeable membrane devices to estimate the contribution of industrial facilities to regional polychlorinated biphenyl budgets
Authors: McCarthy John F , Southworth George R , Ham Kenneth D , Palmer Jennifer A 
Published: March 2010

Abstract
Passive monitoring of polychlorinated biphenyls (PCB) using semipermeable membrane devices (SPMD) was employed to evaluate the contribution of point and nonpoint sources to the flux of PCB in a drainage system encompassing three U.S. Department of Energy (U.S. DOE) industrial and research facilities in eastern Tennessee, USA. Polychlorinated biphenyls concentrations were highest at outfalls containing process waste from the DOE industrial facilities. The significance of these releases was evaluated by calculating the PCB flux (mass per unit time) at different monitoring locations. The flux was calculated from the time-integrated estimates of the aqueous concentrations of PCB and estimates of the volumetric flow rates of discharges and receiving streams during the deployment period. The DOE discharges accounted for most of the flux of PCB entering the Clinch River from the DOE drainage areas, but these sources constituted only 10% of the flux in the Clinch River about the DOE sources. Principal components analysis was helpful in attributing sources of PCB. In a stream receiving multiple inputs of PCB, congener profiles from upstream sources and discrete discharges were consistent with a mixture of those congener profiles in the downstream receiving water. In another stream with a single upstream source of PCB, changes in PCB flux and congener profiles suggested an apparent steady-state distribution between dissolved PCB and PCB adsorbed to organic matter on the streambed. The flux of dissolved PCB along different stream reaches reflected changes in the sediment organic content. Subtle alterations in congener profiles moving downstream suggested preferential desorption of less chlorinated congeners and sorption of more highly chlorinated congeners to sediment. Time-integrated, flux-based monitoring can be useful across a range of spatial scales for evaluating the significance of point and nonpoint contaminant sources and can help identify and prioritize feasible remedial alternatives.
Cadmium dynamics in estuarine sediments: Effects of salinity and lugworm bioturbation
Authors: Rasmussen Allan Dahl , Banta Gary Thomas , Andersen Ole 
Published: March 2010

AbstractWe investigated the effects of lugworm bioturbation on the fate of Cd added either to a thin layer at the sediment surface or homogeneously mixed throughout the sediment. In both situations, the Cd release to the overlying water was highest when lugworms were not present, most likely because bioturbation transported Cd-contaminated sediment away from the sediment surface. Also, irrigation transported water-borne Cd back into the sediment. When Cd was added to the sediment surface, a Cd peak emerged at the feeding depth of the worm within 1 d because of the transport of water-borne Cd down into the sediment by lugworm irrigation. In addition, the conveyor-belt feeding mode of the worm caused both burial of Cd by fecal casts and a gradual spreading of the Cd distribution within the sediment column. When Cd was added to the entire sediment column, bioturbation caused a net transport of Cd upwards, resulting in the surface layers having higher Cd concentrations than the deeper layers, indicating a net release of Cd from deeper sediments. The distribution of Cd in lugworms depended on the Cd exposure situation and suggested that worms were exposed mainly to water-borne Cd when Cd was added to the top of the sediment, whereas worms were exposed mainly by ingesting Cd-labeled sediment when Cd was mixed homogeneously throughout the sediment.
USE of outdoor freshwater pond microcosms: II. Responses of biota to pyridaben
Authors: Rand Gary M , Clark James R , Holmes Catherine M 
Published: March 2010

Abstract
The effects of pyridaben, an insecticide-miticide on zooplankton, macroinvertebrates, and fish were studied in outdoor freshwater microcosms using an analysis of variance design with three chemical concentrations (0.34, 3.4, 34.0 μg/L) and one untreated control randomized among 24 tanks. Each treatment was replicated six times. Monitoring was conducted during an 11-month baseline phase followed by a total of three months for treatment and posttreatment phases. Two applications of a wettable powder formulation were sprayed directly below the water surface with a 30-d interval between treatments. Copepoda adult abundance was significantly reduced at 34.0 μg/L but recovery occurred within 6 weeks after application. Abundance of copepoda nauplii was significantly reduced at 3.4 and 34.0 μg/L, after applications one and two; effects were more severe at 34.0 μg/L and recovery was more rapid at 3.4 μg/L. Abundance of Rotifera was reduced at 34.0 μg/L, after applications one and two, and recovery occurred within 8 weeks for all groups except Polyarthra and Keratella. Of the most abundant Cladocera, abundance of Alona was not significantly affected and abundance of Latonopsis was significantly reduced at 34.0 μg/L, after applications one and two, but recovery occurred within 6 weeks. Abundance of Latonopsis also was significantly reduced at 3.4 μg/L, after applications one and two, but recovery occurred within 2 weeks. A significant decrease occurred in the abundances of Cnidaria, Insecta, and Hydracarina at 34.0 μg/L, only after application one. Pyridaben was toxic to bluegill at 34.0 μg/L, but was not acutely toxic at the laboratory 96-h LC50 concentration (∼3.4 μg/L).
Effects of exposure source, worm density, and sex on DDT bioaccumulation and toxicity in the marine polychaeteNeanthes arenaceodentata
Authors: Lotufo Guilherme R , Farrar J Daniel , Bridges Todd S 
Published: March 2010

AbstractThe influence of exposure source, worm density, and sex on the bioaccumulation and toxicity of 14C-labeled DDT was evaluated for Neanthes arenaceodentata. Emergent juvenile worms were exposed to DDT-spiked sediment (SED), DDT-spiked supplemental food (TetraMarin; TM), or a combination of both (SEDTM) in 28-d toxicity experiments. The DDT concentrations in the sediment and in the food were equal on an organic carbon basis. Higher body residues were attained under the TM exposure compared to SED, indicating the importance of nonsedimentary organic matter as a source for contaminant uptake. The DDT was more bioavailable when associated with TetraMarin compared to sediment, indicating that factors other than sorption to organic carbon can influence contaminant bioavailability. Body residues as high as 0.5 mol/g wet weight were not associated with decreased survival, suggesting general narcosis as the mode of lethal toxicity of DDT to N. arenaceodentata. Most of the body burden was DDT unmetabolized compound (∼70%). Reduced growth, observed under all exposures, was significant at lower concentrations when worms were fed DDT-spiked food (TM and SEDTM). Neanthes arenaceodentata may have detected the presence of DDT in the TetraMarin and decreased their feeding rate, at the cost of reduced growth. The influence of worm density on DDT toxicity and bioaccumulation was examined by exposing one or five worms per beaker (74 and 370 worms/m2, respectively) to spiked sediment. Although higher body residues were attained under low density, worms exposed in groups of five were significantly more sensitive to the effects of DDT on growth. Sex also had a large influence on DDT uptake kinetics. In sediment exposures (SED) to a trace concentration, the uptake clearance rate (mgoc/g lipids/h) was two times more efficient and the elimination rate was five times faster in mature males than in mature females.
Applying species-sensitivity distributions in ecological risk assessment: Assumptions of distribution type and sufficient numbers of species
Authors: Newman Michael C , Ownby David R , Mézin Laurent C A , Powell David C , Christensen Tyler R L , Lerberg Scott B , Anderson Britt-Anne 
Published: March 2010

Abstract
Species-sensitivity distribution methods assemble single-species toxicity data to predict hazardous concentrations (HCps) affecting a certain percentage (p) of species in a community. The fit of the lognormal model and required number of individual species values were evaluated with 30 published data sets. The increasingly common assumption that a lognormal model best fits these data was not supported. Fifteen data sets failed a formal test of conformity to a lognormal distribution; other distributions often provided better fit to the data than the lognormal distribution. An alternate bootstrap method provided accurate estimates of HCp without the assumption of a specific distribution. Approximate sample sizes producing HC5 estimates with minimal variance ranged from 15 to 55, and had a median of 30 species-sensitivity values. These sample sizes are higher than those suggested in recent regulatory documents. A bootstrap method is recommended that predicts with 95% confidence the concentration affecting 5% or fewer species.
Dechlorination of substituted trichloromethanes by an iron(II) porphyrin
Authors: Larson Richard A , Cervini-Silva Javiera 
Published: March 2010

Abstract
Iron(II)porphyrins complex with many organochlorinecompounds and oxidizebydechlorinating them. For a series of trichloromethyl derivatives, CCl3R (R = NO2, CHCl2, CN, Cl, COO−, CH3, H, C(O)NH2, and CH2OH), heme oxidation occurred in two consecutive steps: heme-CCl3R complexation, and (usually slower) inner-sphere electron transfer. Stability of the intermediate CCl2R radical, which is strongly correlated with the ability of the R group to delocalize electron density, governed the overall electron transfer rate.
Structure–activity relationships for acute and chronic toxicity of alcohol ether sulfates
Authors: Dyer Scott D , Stanton David T , Lauth John R , Cherry Donald S 
Published: March 2010

Abstract
Acoholethersulfates(AES)areanionicsurfactantscommonlyusedinconsumerproducts. Commercial AES alkyl chain lengths range from C12 to C18, with ethoxylate (EO) units ranging from 1 to 5. Alkyl sulfate is a special case of AES with no EO units. Acute and chronic toxicity tests using Ceriodaphnia dubia via a novel flowthrough method were conducted with 18 AES compounds to derive SARs for effects assessment. In general, acute toxicity (48-h LC50) increased with increased alkyl carbon chain length and decreased with increased numbers of EO units. Parabolic structure–chronic (7-d) toxicity relationships were observed for endpoints such as the no-observed-effect concentration, lowest-observed-effect concentration, maximum acceptable toxicant concentration, EC20, and EC50. A linear relationship of the fractional negative-charged surface area (FNSA-3) with acute toxicity was also determined. FNSA-3 refers primarily to the polar head group of AES and secondarily to the alkyl chain. Seventy percent of the variance in the chronic data was addressed with a quadratic equation relating toxicity to alkyl chain length and EO units. Alternatively, the molecular descriptors FNSA-3 and S3P (3χp, which is the simple, third-order path index) were also found to address most of the data nonlinearity. A chronic test conducted with a mixture of four AES components indicated additivity, leading to the support of the performance of an effects assessment of AES as a mixture.
Acute toxicity ofpara-nonylphenol to saltwater animals
Authors: Lussier Suzanne M , Champlin Denise , LiVolsi Joseph , Poucher Sherry , Pruell Richard J 
Published: March 2010

Abstractpara-Nonylphenol (PNP), a mixture of alkylphenols used in producing nonionic surfactants, is distributed widely in surface waters and aquatic sediments, where it can affect saltwater species. This article describes a database for acute toxicity of PNP derived for calculating a national saltwater quality criterion. Using a flow-through exposure system with measured concentrations, we tested early life stages of four species of saltwater invertebrates and two species of fish. Static 96-h tests were also conducted on zoeal Homarus americanus, embryo-larval Mulinia lateralis, and larval Pleuronectes americanus. The number of organisms surviving the flow-through test was measured at 2, 4, 8, and 12 h and daily through day 7. Mortality for most species plateaued by 96 h. The ranked sensitivities (96-h 50% lethal concentrations, measured in micrograms per liter) for the species tested were 17 for Pleuronectes americanus, 37.9 (48-h 50% effective concentration) for Mulinia lateralis, 59.4 for Paleomonetes vulgaris, 60.6 for Americamysis bahia (formerly Mysidopsis bahia), 61.6 for Leptocheirus plumulosos, 70 for Menidia beryllina, 71 for Homarus americanus, 142 for Cyprinodon variegatus, and &gt; 195 for Dyspanopius sayii. Values for the seven most sensitive of these species ranged over a factor of only 4.2. The narrow range of responses for PNP implies that exceeding a threshold concentration would endanger a large proportion of the aquatic community.
Kinetics of waterborne strontium uptake in the common carp, Cyprinus carpio, at different calcium levels
Authors: Chowdhury Mohammed J , Van Ginneken Luc , Blust Ronny 
Published: March 2010

Abstract
The uptake kinetics of strontium in the commoncarp(Cyprinus carpio) were characterized in vivo, exposing preac-climated fish to a wide range of Sr2+ (0.27 μM–10.0 mM) and Ca2+ (10 μM–10 mM) concentrations in water; 85Sr, 45Ca, and 47Ca were used as tracers in determining the uptake, and the possibility of adsorption of the tracers to the exterior of the fish were verified. The uptake rates were determined in the whole body, gills, and blood of the fish after an exposure period of 3 h and were analyzed as a function of the free-ion activity of strontium and calcium in water. With the increase of Sr2+ concentration in the exposure water, Sr2+ uptake did not increase linearly but displayed Michaelis–Menten saturation kinetics, and with the increase of Ca2+ concentration, Sr2+ uptake decreased significantly in the whole body, gills, and blood. The competitive inhibition model fitted to the pooled data for whole-body uptake explains about 94% of the variation in Sr2+ uptake and 71% in Ca2+ uptake, indicating a competitive type of interaction during the transport of these metal ions across the biological interfaces. The maximum uptake rate of Sr2+ (JmaxSr) was estimated to be 243.0 μmol/kg/h and that of Ca2+ (JmaxCa) 119.4 μmol/kg/h. The apparent Km for Sr2+ uptake increased greatly with the increase of Ca2+ concentration in water (186, 789, and 5,515 μM for 35, 348, and 3,480 μM Ca2+, respectively). Estimation of the true Km for Sr2+ uptake (KmSr) and its inhibitor constant for Ca2+ (KiCa) yielded the values of 96.3 and 28.5 μM, respectively. These values are very close to those obtained for Ca2+ uptake (KmCa = 24.9 and KiSr = 100.9 μM). This model provides a mechanistic description of the effect of calcium on strontium uptake from water and, vice versa, in carp.
Organochlorine exposure and bioaccumulation in the endangered Northwest Atlantic right whale (Eubalaena glacialis) population
Authors: Weisbrod Anne V. , Shea Damian , Moore Michael J , Stegeman John J 
Published: March 2010

Abstract
Exposure to toxicants is one factor hypothesized to influence population growth of the northern right whale. Organo-chlorines in right whale skin, feces, and prey were measured and used to identify factors influencing exposure and bioaccumulation. Concentrations of 30 polychlorinated biphenyls (PCBs) (5.7 ± 8.9 μg/g lipid) and 20 pesticides (11.4 ± 15.4 μg/g lipid) in skin biopsies were consistent with other baleenopterids. Concentrations in feces and prey were two orders of magnitude less than in biopsies. In principal component analysis, organochlorines in biopsies matched those from Bay of Fundy, Canada, zooplankton, whereas feces were like Cape Cod, USA, copepods. Year of biopsy collection was the principal factor associated with differential accumulation of nonmetabolizable PCBs, 4,4′-DDE, and dieldrin. Biopsies collected during winter had lower concentrations of lipid and metabolizable compounds than biopsies collected during summer. Concentrations of metabolizable PCBs increased with age in males. The bioaccumulation patterns implied that blubber burdens change annually because of the ingestion of different prey or prey from distinct locations and the release of some organochlorines stored in blubber during lipid depletion in winter. Because biopsy concentrations were lower than those found in marine mammals affected by PCBs and DDTs, we do not have evidence that the endangered whales bioaccumulate hazardous concentrations of organochlorines.
Toxic effects of cadmium and zinc on ectomycorrhizal colonization of scots pine (Pinus sylvestris L.) from soil inoculum
Authors: Hartley-Whitaker Jeanette , Cairney John W G , Meharg Andrew A 
Published: March 2010

Abstract
Scots pine seedlings colonized by ectomycorrhizal (ECM) fungi from natural soil inoculum were exposed to a range of Cd or Zn concentrations to investigate the effects of metals on ECM fungi–Scots pine associations in a realistic soil environment. Experiments focused on the relationship between the sensitivity of ECM fungi and their host plants, the influence of metals on ECM community dynamics on Scots pine roots, and the effects of metal exposure on ECM colonization from soil-borne propagules. Ectomycorrhizal colonization was inhibited by Cd and Zn, with a decrease in the proportion of ECM-colonized root tips. Shoot and root biomass, total root length, and total root-tip density, however, were unaffected by Cd or Zn. A decrease in the diversity of ECM morphotypes also occurred, which could have a negative effect on tree vigor. Overall, colonization by ECM fungi was more sensitive than seedling growth to Cd and Zn, and this could have serious implications for successful tree establishment on metal-contaminated soils.
Responses of a macroinvertebrate community from a pristine, southern British columbia, Canada, stream to metals in experimental mesocosms
Authors: Richardson John S , Kiffney Peter M 
Published: March 2010

Abstract
Metal contamination is one of the most widespread impacts onsurface waters. Experimental flumes receiving water and aquatic invertebrates from an undisturbed, forested stream were used to determine the impact of metals in a low-conductivity stream. The experimental flumes were exposed to a gradient of doses maintaining a constant ratio of metals (1995: Cu, Zn, Mn, and Pb; 1996: Cu and Zn) for 6 d. Benthos and emigration were sampled from each of the 16 troughs. The overall densities of benthos declined, but not significantly, as the dose of metals increased. On the basis of the slopes of the concentration–response curve, Baetis, Ameletus, and Paraleptophlebia were the most sensitive taxa present. Other taxa (e.g., Nemouridae and Oligochaeta) were mildly affected by high metal concentrations. Chironomidae showed no significant decrease in densities with increasing dose. Chironomids made up &gt;80% of the benthos and is the primary reason for no significant dose effect on overall densities. No treatment effect was observed on either algal standing crop or bacterial respiration rates. The invertebrate genera most affected by exposure to metals in this study were also absent or rare in nearby urban streams with high metal concentrations.