bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inventories and fluxes of polychlorinated biphenyls from a contaminated industrial site
Authors: Axelman Johan , Broman Dag 
Published: March 2010

Abstract
Örserum Bay is a semienclosed small bay on the Swedish east coast. A paper mill for recycled paper, situated by the bay, has released several hundred kilograms of polychlorinated biphenyls (PCBs) into the bay. A large part of the sediment was later dredged and placed in a deposit site on land. In the present investigation, the inventories of PCBs in the sediments outside the mill and various other matrices on the estate have been estimated. The release of PCBs to the surrounding environment via air, water in the bay, and groundwater was also assessed. The two major processes were volatilization from the deposit of contaminated sediments and release from bay sediments with subsequent advective water transport and volatilization. Estimates of the rate of removal in percent per year for different homolog groups clearly demonstrated that fluxes rather than concentrations should be considered in risk assessments of contaminated sites. The properties and location of the contaminated matrix governed the magnitude of the PCB leakage. In addition, the impact of physicochemical properties of the different PCB homolog groups on their environmental behavior was clear. The rate of removal from the deposit reached a maximum for tetrachlorobiphenyls (tetra-CBs), for which the rate was 0.03%/year. Measured volatilization transfer velocities in the soil at the deposit ranged from 3 × 10−11 to 1 × 10−8 cm/s. In the bay, the PCBs were much more mobile, even though there were smaller differences between the homolog groups. The dichlorobiphenyls (di-CBs) showed a rate of removal from the bay of 1.6 %/year. The rate decreased with increasing degree of chlorination up to pentachlorobiphenyls (penta-CBs). Pentachlorobiphenyls to octachlorobiphenyls (octa-CBs) were removed from the bay at a rate of 0.4 to 0.6%/year.
Mineralization of dimethylsilanediol by microorganisms isolated from soil
Authors: Sabourin Cheryl L , Carpenter John C , Leib Terry K , Spivack James L 
Published: March 2010

Abstract
Previous studies have shown that polydimethylsiloxane is hydrolyzed in soil to dimethylsilanediol and that dimethylsilanediol is biodegraded in soil. Previously, two soil microorganisms capable of biodegrading dimethylsilanediol were isolated and identified. In this paper, the extent of [14C]dimethylsilanediol biodegradation by these two soil microorganisms, Fusarium oxysporum Schlechtendahl and an Arthrobacter species, is investigated. The silicon-containing products of dimethylsilanediol biodegradation in liquid culture were identified by high-performance liquid chromatography coupled to argon plasma emission spectrometry (HPLC-ICP). The biodegradation of [14C]methylsilanetriol was investigated in liquid cultures and in soil by monitoring the production of 14CO2. The sorption coefficient of [14C]methylsilanetriol was determined, and the sorption coefficient of [14C]dimethylsilanediol was estimated, by measuring the amount of 14C counts in the water phase of a water-soil mixture. Methylsilanetriol was found to be mineralized in liquid cultures of F. oxysporum Schlecht. and the Arthrobacter sp. that were supplied with a primary carbon source. However, the production of 14CO2 from [14C]methylsilanetriol in soil experiments never exceeded the level of possible [14C]-containing impurities in the methylsilanetriol. Methylsilanetriol was found to be more strongly sorbed to soil, which might have reduced its bioavailability. Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer dimethylsilanediol, which is biodegraded in soil. Now mineralization of dimethylsilanediol to inorganic silicate has been demonstrated.
Effects of exposure to municipal wastewater in situ on the reproductive physiology of the fathead minnow (Pimephales promelas)
Authors: Nichols Krista M , Miles-Richardson Stephanie R , Snyder Erin M , Giesy John P 
Published: March 2010

Abstract
Effects of representative central Michigan wastewater treatment plant (WWTP) effluents on the reproductive physiology of fathead minnows (Pimephales promelas) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17β-estradiol (E2), and testosterone (T), and evaluating gonad histology and male secondary sex characteristics. Caged adult male and female fathead minnows were exposed for 3 weeks to WWTP effluent. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. Plasma concentrations of VTG, E2, and T in female fish, quantified by enzyme-linked immunosorbent assay (ELISA), were greater at the lacustrine site than the riverine site or WWTP sites. None of the male fish had mean plasma VTG concentrations similar to that observed in females. Most VTG concentrations in male fish were less than the VTG ELISA detection limit. Female plasma concentrations of E2 were similar among riverine and WWTP sites. Plasma concentrations of E2 in male fish were greater than the riverine site at all WWTP sites except the Williamston site, but were not significantly different from the lacustrine site. Concentrations of T in female and male fish were similar among riverine and exposure sites. No trends in hormone concentrations, male secondary sex characteristics, or gonad histology could be attributed to putative endocrine disrupter exposure in WWTP effluent. The results indicate that the risk for estrogen agonist exposure below these central Michigan WWTPs is small.
Bioaccumulation of 2,2′,5,5′-tetrachlorobiphenyl and pyrene by picoplankton (Synechococcus leopoliensis, cyanophyceae): Influence of variable humic acid concentrations and pH
Authors: Twiss Michael R , Granier Laurent , Lafrance Pierre , Campbell Peter G C 
Published: March 2010

Abstract
Natural dissolved organic matter (DOM) controls the aqueous phase partitioning of hydrophobic organic contaminants (HOCs), where the sum of aqueous HOCs is distributed between the bound and free forms of HOCs, that is [HOC-DOM]↔[HOC] + [DOM]. The hypothesis that the bioavailability of aqueous HOCs can be attributed solely to the concentration of the free form of HOCs was tested. Bioavailability was measured as accumulation of [14C]-PCB (IUPAC 52) and [14 C]-pyrene over 48 h by the phytoplanktonic cyanobacterium Synechococcus leopoliensis. The phytoplankton were exposed within dialysis sacs to freely dissolved HOC at concentrations that were similar in all sacs (freely dissolved PCB ∼ 125 ng/L, freely dissolved pyrene ∼55 ng/L). However, humic acid concentrations were varied among the sacs (Suwannee River humic acid [HA] = 0, 2, 5, or 20 mg/L). The experiment was designed to vary the concentrations of HOC-HA and HA while keeping the concentration of freely dissolved HOCs at the same levels in all the sacs. Sorption mechanisms were probed by manipulating the pH of the exposure medium; the hydrophobicities of the cell surface and the humic acid are pH-sensitive, whereas the freely dissolved concentration of HOCs is pH-invariant. Bioaccumulation was predominantly controlled by the freely dissolved concentration of HOC and was greater at pH 4.3 than at pH 7.3. Although sorption of the PCB-HA and pyrene-HA complexes by S. leopoliensis occurred, this mechanism did not contribute significantly to the total accumulation of PCB or pyrene. These results suggest that the accumulation of HOCs by planktonic microorganisms can be predicted on the basis of the concentration of freely dissolved HOC molecules.
Exposure of northern leopard frogs in the green bay ecosystem to polychlorinated biphenyls, polychlorinated dibenzo—p-dioxins, and polychlorinated dibenzofurans is measured by direct chemistry but not hepatic ethoxyresorufin—o-deethylase activity
Authors: Huang, Yue—Wern , Karasov, William H , Patnode, Kathleen A , Jefcoate Colin R 
Published: March 2010

Abstract
We measured concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in northern leopard frogs collected from the Green Bay ecosystem and explored the catalytic activity of hepatic cytochrome P450-associated monooxygenase (P450 enzyme) as a biomarker for exposure to aryl hydrocarbon receptor (AhR) agonists. The two hypotheses tested were PCH concentrations in northern leopard frogs would be positively correlated with sediment polychlorinated hydrocarbon (PCH) levels in wetland habitats along a contamination gradient and hepatic ethoxyresorufin-O-deethylase (EROD) activity of northern leopard frogs, which is presumably mediated by aryl hydrocarbon receptor (AhR), would be positively correlated with PCH concentrations in frog carcasses (whole body minus liver) from different collection sites. In 1994 to 1995, frogs from seven sites along the lower Fox River and Green Bay, USA, were assayed for hepatic EROD activities and whole carcass concentrations of PCBs, PCDDs, and PCDFs. Tissue total PCB concentrations ranging from 3 to 154 ng/g were significantly correlated with sediment PCB levels. Only one PCDD and two PCDFs at concentrations of 6 to 8 pg/g were found in the frogs collected from one of the sites. The EROD activity in frogs ranging from 186 to 270 pmol/min/mg protein was not significantly correlated with frog body weight and was similar among sites except for Peter's Marsh. No significant correlation was found between EROD activity and carcass PCB concentration. This result was consistent with the fact that the frogs collected from the Green Bay ecosystem had relatively low PCB concentrations compared with what was required for induction in the laboratory (ED50 for EROD is between 700 and 2,300 ng/g).
Effects of pond water, sediment, and sediment extracts from minnesota and vermont, USA, on early development and metamorphosis of xenopus
Authors: Fort Douglas J , Propst Timothy L , Stover Enos L , Helgen Judy C , Levey Rick B , Gallagher Kathryn , Burkhart James G 
Published: March 2010

Abstract
In recent studies, a high incidence of amphibian mortality and malformation has been reported in the field, suggesting that toxic and/or bioactive agents are present in the environment of the affected amphibians. This study provides evidence for this hypothesis, because it applies to several affected ponds in Minnesota and Vermont, USA. Three developmental bioassays were carried out on samples from three reference and three test sites in Minnesota and one reference and three test sites, in Vermont. The bioassays utilized Xenopus as a model system, measuring altered developmental patterns during the first 4 d of development (frog embryo teratogenesis assay-Xenopus [FETAX]), hind—limb development over a 30-d period, and tail length resorption over a 14-d period. Strong correlations were observed among the results for all three in vitro bioassays, as well as between adverse developmental effects in vitro and in the field.
Biocide testing using particles with controlled surface properties (artificial sediments)
Authors: Davies Nicola A , Edwards Paul A , Lawrence Monique AM , Simkiss Ken , Taylor Marina G 
Published: March 2010

AbstractSediments may play an important role in the accumulation of contaminants by benthic organisms. This work uses artificial particles to model natural systems and to provide a way of predicting bioavailability from sediment/contaminant interactions. The artificial particles used were a range of high performance liquid chromatography resins and a dimethylditallow ammoniumexchanged clay. The bioavailability of 2,4-dichlorophenol on these particles to the midge larva Chironomus riparius was compared with that from sand and a natural sediment. The experiments were designed so that water uptake and accumulation due to the ingestion of particles could be distinguished. The results show that very strong or very weak electrostatic interactions of the contaminant with the particles results in little accumulation of the contaminant via ingestion. When the contaminant is weakly bound to the particles by van der Waals forces, the contaminant can be released from the ingested particles. In these experiments, this occurred when the contaminant–particle interaction was hydrophobic, and it is under these conditions that 2,4-dichlorophenol was most bioavailable.
Bioaccumulation and toxicity of tributyltin to a burrowing heart urchin and an amphipod in spiked, silty marine sediments
Authors: Stronkhorst Joost , van Hattum Bert , Bowmer Tim 
Published: March 2010

Abstract
The presence of tributyltin (TBT) in silty sediments is regarded as a long—term threat to marine and estuarine environments due to its persistence. The bioaccumulation kinetics and toxicity of TBT in the deposit—feeding heart urchin Echinocardium cordatum was studied in silty sediment spiked with TBT and equilibrated prior to the 28-d exposure. An additional 10-d acute toxicity test was carried out with the burrowing amphipod Corophium volutator in the same sediment. Because E. cordatum has a low lipid content and apparently high elimination and metabolic rates, only a moderate degree of TBT bioaccumulation was observed, with biota—sediment accumulation factors (BASFs) of 0.09 to 0.21 (dry weight basis) and biota accumulation factors (BAFs) of 180 to 843 (wet weight basis). The lethal body residue in E. cordatum (soft tissue and skeleton) was 0.8 to 3.4 nmol TBT+/g wet weight which, considering the differences in lipid content, is comparable to data on other taxonomic groups. For E. cordatum and C. volutator, the LC50s for pore water (222 and 329 ng Sn/L) were also close to reported values for aquatic and benthic organisms. The TBT concentrations in the pore water of the silty sediment were much lower than might be expected from the octanol—water partition coefficient. The measured sediment—water partitioning coefficient Kp was 8,700 L/kg dry weight. Consequently, toxicity was observed at a relatively high TBT concentration in the bulk sediment with LC50s for E. cordatum and C. volutator of 1,594 and 2,185 ng Sn/g dry weight, respectively. The results show that TBT is highly toxic to the benthic species investigated and sorption in the silty sediment strongly reduced the bioavailability of the compound.
Comparison of the toxicity of dimethoate and cypermethrin in the laboratory and the field when applying the same bioassay
Authors: Akkerhuis Gerard A.J.M. Jagersop , Damgaard Christian , Kjær Christian , Elmegaard Niels 
Published: March 2010

Abstract
The present paper studies the relationship between laboratory- and field—based survival data of beetle larvae sprayed with either dimethoate or cypermethrin. The comparison for dimethoate was based on an earlier constructed pesticide—effect model derived from greenhouse data. To predict field effects, the model was supplied with field data for temperatures, the insecticide concentrations on the plants, and the control mortality rate of the beetles. The same model structure was unable to predict greenhouse mortality from cypermethrin treatment, for which reason the differences between laboratory and field for this compound are discussed on the basis of direct observations. For best comparison, the same bioassay method was used in both the greenhouse and the field in the present study. Tests were based on Gastrophysa polygoni larvae dwelling on the undersides of leaves of Fallopia convolvulus plants. Dietary uptake was regarded as the main source of exposure. The simulation results for dimethoate underestimated the field mortality even after accounting for the higher control mortality in the field in the model. It was shown that an additional increase of the toxicant—induced death rate by more than a factor of five was required for the model to fit the field data. This indicated a relatively severe impact of dimethoate under field conditions. For cypermethrin, the effects in the field increased with time, pointing at increasing exposure of and/or effects on the larvae. Contributions of the present results toward the bridging of the gap between laboratory and field are discussed.
Lead effects on the predictability of reproductive behavior in fathead minnows (Pimephales promelas): A mathematical model
Authors: Alados Concepción L , Weber Daniel N 
Published: March 2010

Abstract
Lead (Pb) has been shown to affect the behavior of a wide variety of vertebrates, including fish, amphibians, and mammals. This article re—examines previous data on the effect of short—term, sublethal levels of waterborne Pb on the reproductive behavior of fathead minnows (Pimephales promelas). Previous research has found that Pb decreased the time spent in displaying specific reproductive behaviors in male minnows. Because each activity performed within a sequence depends upon previous parts of the sequence, the reproductive behavior of fish is not randomly distributed but is presented as a long—range self—similar correlation. By treating these data as a fractal dimension, it is now possible to determine changes in the long—term correlation of different behavioral sequences involved in nest maintenance owing to Pb exposure (0.5 ppm Pb as Pb acetate), both before and after adult males attain reproductive maturity. We hypothesized that the scaling exponent of this fluctuation varies in relation with environmental contaminants. Known Pb—induced changes in hormonal activity may account for changes in observed reproductive and nest maintenance behaviors. Pb—exposed fish exhibited higher levels of predictability (less complexity) in their behavioral sequences, i.e., they demonstrated an increase in the scaling parameter of the fluctuation a. However, if Pb was introduced after sexual maturity was observed, there was no significant difference in the scaling component a. Thus, the use of fractal dimension may provide a useful tool to analyze the effects of environmental contaminants and other stresses.
Accumulation of polycyclic aromatic hydrocarbons in semipermeable membrane devices and caged mussels (Mytilus edulis L.) in relation to water column phase distribution
Authors: Axelman Johan , Næs Kristoffer , Näf Carina , Broman Dag 
Published: March 2010

Abstract
Semipermeable membrane devices (SPMDs) and blue mussels (Mytilus edulis L.) were deployed at a site contaminated by discharges of polycyclic aromatic hydrocarbons (PAHs) from an aluminium reduction plant, and at a reference site. The accumulation of PAHs in SPMDs versus mussels, along with the ability of the two matrices to predict contaminant concentrations in the ambient environment, were evaluated through concurrent measurements of particulate, dissolved, and colloidal PAHs in the water column. Analysis of the results showed that blue mussels were more efficient at sequestering PAHs than were SPMDs. The PAH profile (i.e., the relative abundance of individual PAHs) in the two matrices were similar, but differed significantly from the profile in the dissolved phase. Further, back-calculation of the ambient dissolved concentrations from SPMDs indicated systematic overtrapping with increasing hydrophobicity. Calculation of in situ bioconcentration factors (BCFs) for the blue mussels at the smelter site indicated that uptake via particles (&gt;0.7 μm) or from colloids dominated over direct uptake from the dissolved phase, as opposed to the reference site. The in situ BCFs differed markedly from literature values, which implies that the use of mussels to predict ambient concentrations would require that site-specific BCFs be applied.
Exposure modeling of detergent surfactants—prediction of 90th-percentile concentrations in the Netherlands
Authors: Feijtel Tom C J , Struijs Jaap , Matthijs Eddy 
Published: March 2010

Abstract
The exposure assessment portion of an environmental risk assessment involves developing an understanding of the potential fate of materials in the environment and the use of this information to determine a predicted environmental concentration (PEC). The aquatic risk assessment for detergents in the Netherlands is based on the comparison of the 90th percentile of PECs—calculated at 1,000 m downstream the sewage outfall—to the predicted no-effect concentration (PNEC) for ecosystems or maximum permissible concentration (MPC). The 90th-percentile surfactant concentrations at 1,000 m downstream the sewage outfall can be calculated using information on release, in-sewer removal, treatment efficiency, dilution, and in-stream removal. Predicted average removals for linear alkyl benzene sulfonate (LAS), alcohol ethoxylates (AE), alcohol ethoxylated sulfates (AES), and soap were high (98–99%) and not significantly different, using the specified model input. This implies that—within the limitations of the model—only 1 to 2% of total mass entering the wastewater system will be discharged to the receiving surface waters. The monitoring data confirm the effective removal and degradation of the four major detergent surfactants during treatment in activated sludge plants and indicate that the model predictions on removal are conservative. Average measured removal ranged from 99.1% for soap to 99.8% for alcohol ethoxylates. Predicted 90th-percentile surfactant concentrations at 1,000 m downstream the sewage outfall—based on actual measured raw sewage concentrations, measured mean wastewater removal figures, and predicted in-stream removal rates—ranged from 0.5 μg/L for AE to 20 μg/L for soap.
Determination of silver speciation in wastewater and receiving waters by competitive ligand equilibration/solvent extraction
Authors: Adams Nicholas W H , Kramer James R 
Published: March 2010

Abstract
A competitive ligand equilibration/solvent extraction (CLE/SE) technique was used to examines silver complexation in the particulate (&gt;0.45 μm), colloidal (&lt;0.45 μm), and dissolved (&lt;10 kDa) states of wastewater effluent and receiving waters. Additions of silver at near ambient levels (0.1–10 nM), followed by CLE/SE, allowed the determination of complexation sites with large stability constants (log KAgL = 11–12) responsible for silver binding. Good agreement between these constants and formation constants of well-characterized silver sulfide complexes suggests that silver in wastewater effluents and receiving waters is likely to be complexed to sulfur(—II). This is supported by previously collected data on silver and sulfide concentrations in these waters, which showed that inorganic sulfide concentrations are 200 to 300 times in excess of silver concentrations. Organic ligands appear to be insignificant in comparison to the contribution of inorganic ligands to silver binding. These inorganic ligands probably consist of metal sulfides, which are stable for hours and days in oxic waters. When complexed to these strong-affinity ligands, silver(I) is protected from photoreduction to zero-valent silver.
Acclimation-induced changes in the toxicity of zinc and cadmium to rainbow trout
Authors: Stubblefield William A , Steadman Bryan L , La Point Thomas W , Bergman Harold L 
Published: March 2010

Abstract
Adults and juvenile rainbow trout exposed for 21 d to sublethal levels of zinc or cadmium exhibited significant changes in their respective incipient lethal levels (ILL). Acclimation resulted in exposure-dependent changes in both tolerance (ILL concentration) and resistance (time to ILL) in both size classes of fish for each metal. The ILLs for adult rainbow trout exposed to zinc increased from 695 μg/L at 131 h for nonacclimated fish to 2,025 μ/L at 168 h for fish previously exposed to 0.5 ILL (324 μg/L zinc). The ILLs for cadmium-exposed fish increased from 6 μg/L at 187 h for nonacclimated fish to 122 μg/L at 266 h for fish acclimated to 0.5 ILL (10.2 μg/L cadmium). Similar, although somewhat less dramatic, acclimation responses were observed for juveniles with both zinc and cadmium. Juveniles were found to be approximately three times less sensitive to the toxic effects of the metals than were adult fish.