bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heritable reproductive effects of benzo[a]pyrene on the fathead minnow (Pimephales promelas)
Authors: White Paul A , Robitaille Sophie , Rasmussen Joseph B 
Published: March 2010

Abstract
Environmental toxicologists rarely investigate multigeneration effects of aquatic contaminants. In this study we investigated the survivorship of fathead minnow larvae two generations removed from an exposure to the potent mutagen benzo[a]pyrene. The F2 broods with a grandparental exposure history showed a marked decrease in survival. In the highest-exposure group, reproductive capacity and larval survivorship were significantly lower than the solvent control.
Bioavailability of heavy metals in terrestrial and aquatic systems: A quantitative approach
Authors: Plette Alexandra C C , Nederlof Maarten M , Temminghoff Erwin J M , van Riemsdijk Willem H 
Published: March 2010

Abstract
Speciation and bioavailability are the keywords in the relation between the total metal content of the system and the resulting effects for biota. The metal ion binding to the biotic surface is pH dependent, as is metal ion binding to soils. The binding of a metal ion to the biotic surface of an organism when present in soil can decrease with increasing pH, whereas the binding behavior of the biotic surface as such will always increase with increasing pH. The metal toxicity for plants often increases with increasing pH for water culture experiments, in which the opposite effect is observed for plants growing in soils. These seemingly contradictive observations can be explained by considering the interaction between an organism and metal ions present in soil to be the result of competition for that metal ion by all components (including the organism) present in the system. This concept is illustrated on the basis of model calculations concerning pH-dependent copper binding to maize root cell walls, fungal mycelia, and yeast cells present in a sandy soil and concerning cadmium binding to a bacterium present in a clay and a sandy soil as influenced by pH and calcium concentration. In addition, the concept is applied for calculating the impact of algal bloom on the copper speciation in an aquatic system. The concept might be a valuable tool in predicting quantitatively the metal ion sorption to biota present in a complex system and to predict the relative change in availability due to environmental changes.
Chemical characterization of organic constituents from sulfide-rich produced water using gas chromatography/mass spectrometry
Authors: Witter Amy E , Jones A Daniel 
Published: March 2010

Abstract
Dichloromethane extracts of oil field wastewater samples collected over a period of 3 months were characterized using gas chromatography/mass spectrometry (GC/MS). Concentrations and profiles of semivolatile organics exhibited significant change during the sampling period. All seven produced water samples contained benzene, toluene, xylenes, fatty acids, phenols, N, N-dimethylalkylamines, and elemental sulfur. Elemental sulfur levels, including suspended particles, ranged from 0.6 to 42 mg/L. The polysulfide heterocycles 3,5-dimethyl-1,2,4-trithiolane, 3,6-dimethyl-1,2,4,5-tetrathiane, 4,6-dimethyl-1,2,3,5-tetrathiane, and 3,7-dimethyl-1,2,4,5,6-pentathiepane were found in a single produced water sample collected midway through the sampling period. Combined concentrations of these substances reached 41 mg/L. The appearance of polysulfide heterocycles occurred after a near stoichiometric drop in elemental sulfur levels concurrent with samples reaching the pH reported as optimum for sulfhydrogenase-mediated reduction of elemental sulfur, yet samples of similar pH collected later did not contain these unusual organosulfur compounds. Putative precursors of polysulfide heterocycles are hydrogen sulfide, resulting from elemental S(0) reduction, and acetaldehyde. Changes in profiles of other produced water constituents implicate microbial reduction of elemental sulfur as a critical determinant of levels and types of organosulfur compounds in produced waters.
Effects of a nonionic surfactant on biodegradation of phenanthrene and hexadecane in soil
Authors: Macur Richard E , Inskeep William P 
Published: March 2010

Abstract
The influence of a nonionic (alcohol ethoxylate) surfactant (Witconol SN70) on biodegradation of phenanthrene and hexadecane (nonaqueous-phase liquid) in soil was studied in batch and transport systems. Simultaneous enhancement of phenanthrene and hexadecane degradation was noted at surfactant doses resulting in aqueous-phase surfactant concentrations below the critical micelle concentration (CMC). Conversely, degradation rates of both compounds declined to essentially zero at supra-CMC doses, suggesting that distinct mechanisms of inhibition and enhancement were operating depending on the effective surfactant concentration (i.e., accounting for surfactant sorption, log KD = 2.2 L/kg). Surfactant doses resulting in enhanced degradation correlated with enhanced gross microbial activity as determined using total CO2 evolution rates. Supra-CMC doses that resulted in inhibited degradation did not suppress gross microbial activity. Furthermore, measurements of phenanthrene solubilization and surface tension indicated that phenanthrene was solubilized at supra-CMC levels of surfactant. Mechanisms of inhibition of phenanthrene and hexadecane degradation at supra-CMC surfactant concentrations may include changes in interfacial chemistry and subsequent mass transfer processes due to sorbed surfactant, reduced bioavailability of micelle-bound phenanthrene and hexadecane, or inhibition of specific members of the microbial community responsible for hydrophobic organic compound degradation.
Soil and vegetation fluoride exposure pathways to cotton rats on a petrochemical-contaminated landfarm
Authors: Schroder Jackie L , Basta Nicholas T , Rafferty Dan P , Lochmiller Robert L , Kim Soochong , Qualls Charles W , McBee Karen 
Published: March 2010

Abstract
Total fluoride (F) content of soils, vegetation, and cotton rats (Sigmodon hispidus) was measured on a landfarm contaminated with petrochemical wastes. A potentially bioavailable form of F was determined by HCI extraction of soils and vegetation. Cotton rats from the landfarm were examined for dental lesions indicative of fluorosis. Exposure pathways including dietary ingestion of unwashed vegetation and nondietary ingestion of soil associated with grooming and burrowing were evaluated. Mean bone F (1,515 mg/kg) and mean soil total F (1,954 mg/kg) from the landfarm site were greater than bone F (121 mg/kg) and soil total F (121 mg/kg) at a reference site. The HCI-extractable F was elevated in landfarm soil (326 mg/kg) compared to the reference site (2.3 mg/kg). About 80% of the cotton rats collected from the landfarm had dental fluorosis. During winter, the dietary pathway consisted of 78.9% of the potential bioavailable exposure (HCI-extractable F) of the two exposure pathways. However, in the summer, the nondietary pathway consisted of 87.9% of the potential bioavailable exposure of the two pathways. Incidental ingestion of soil associated with grooming and burrowing is more important than consumption of unwashed vegetation for cotton rats on the landfarm site in the summer. Fluoride accumulation in the soil from landfarming of petroleum wastes may pose a risk to terrestrial vertebrates. In addition to monitoring petroleum hydrocarbons, land application of petrochemical wastes should consider F and other inorganic contaminant loadings to the soil system.
Assimilation efficiencies of chemical contaminants in aquatic invertebrates: A synthesis
Authors: Wang Wen-Xiong , Fisher Nicholas S 
Published: March 2010

AbstractAssimilation efficiencies of contaminants from ingested food are critical for understanding chemical accumulation and trophic transfer in aquatic invertebrates. Assimilation efficiency is a first-order physiological parameter that can be used to systematically compare the bioavailability of different contaminants from different foods. The various techniques used to measure contaminant assimilation efficiencies are reviewed. Pulse-chase feeding techniques and the application of gamma-emitting radiotracers have been invaluable in measuring metal assimilation efficiencies in aquatic animals. Uniform radiolabeling of food is required to measure assimilation, but this can be difficult when sediments are the food source. Biological factors that influence contaminant assimilation include food quantity and quality, partitioning of contaminants in the food particles, and digestive physiology of the animals. Other factors influencing assimilation include the behavior of the chemical within the animal's gut and its associations with different geochemical fractions in food particles. Assimilation efficiency is a critical parameter to determine (and to make predictions of) bioaccumulation of chemicals from dietary exposure. Robust estimates of assimilation efficiency coupled with estimates of aqueous uptake can be used to determine the relative importance of aqueous and dietary exposures. For bioaccumulation of metals from sediments, additional studies are required to test whether metals bound to the acid-volatile sulfide fraction of sediments can be available to benthic deposit-feeding invertebrates. Most assimilation efficiency studies have focused on chemical transfer in organisms at the bottom of the food chain; additional studies are required to examine chemical transfer at higher trophic levels.
Humic acids reduce the bioaccumulation and photoinduced toxicity of fluoranthene to fish
Authors: Weinstein John E , Oris James T 
Published: March 2010

AbstractThe effects of dissolved humic materials (DHM) on the photoinduced toxicity of fluoranthene to juvenile fathead minnows (Pimephales promelas) were studied in single-treatment evaluations in a laboratory system under simulated sunlight (UV-A = 140.2 ± 2.6 μW/cm2, UV-B = 6.40 ± 0.21 μW/cm2) (mean ± SE). Five concentrations of fluoranthene (0, 4.8, 9.7, 16.4, and 34.0 μg/L) and five concentrations of DHM (0, 0.5, 1.0, 2.5, and 5.0 mg C/L) were achieved. The presence of DHM reduced the acute photoinduced toxicity of fluoranthene. Regression analysis revealed that median lethal times (LT50) were directly related to DHM concentration and inversely related to fluoranthene water concentration. The presence of DHM also reduced fluoranthene bioaccumulation, and LT50 values were inversely related to fluoranthene body residues. These findings demonstrate that (1) the photoinduced toxicity of fluoranthene (like other polycyclic aromatic hydrocarbons) is dependent on body residue and (2) sitespecific environmental parameters that affect uptake and/or elimination can determine the rates of mortality due to photoinduced toxicity.
A model to predict threshold concentrations for toxic effects of chlorinated benzenes in sediment
Authors: Fuchsman Phyllis C , Duda Deborah J , Barber Timothy R 
Published: March 2010

AbstractA probabilistic model was developed to predict effects threshold concentrations for chlorinated benzenes in sediment. Based on published quantitative structure-activity relationships relating the toxicity of chlorinated benzenes to the degree of chlorination, congeners with the same number of chlorine substitutions were considered toxicologically equivalent. Hexachlorobenzene was excluded from the assessment based on a lack of aquatic toxicity at the water solubility limit. The equilibrium partitioning approach was applied in a probabilistic analysis to derive predicted effects thresholds (PETs) for each chlorinated benzene group, with model input distributions defined by published log Kow values and aquatic toxicity data (LC50s and acute to chronic ratios) extracted from the published literature. The probabilistic distributions of PETs generally increased with chlorination, with 20th percentile values ranging from 3.2 mg/kg1%OC for chlorobenzene to 67 mg/kg1%OC for tetrachlorobenzene congeners. The toxicity of total chlorinated benzenes in sediment can be assessed by applying the PETs in a toxic index model, based on the assumption that multiple chlorinated benzene congeners will show approximately additive toxicity, as characteristic of nonpolar narcotic toxicants. The 20th percentile PET values are one to two orders of magnitude higher than published screening-level guidelines, suggesting that the screening-level guidelines will provide overly conservative assessments in most cases. Relevant spiked sediment toxicity data are very limited but seem consistent with the probabilistic model; additional testing could be conducted to confirm the model's predictions.
Literature-derived bioaccumulation models for earthworms: Development and validation
Authors: Sample Bradley E , Suter Glenn W , Beauchamp John J , Efroymson Rebecca A 
Published: March 2010

Abstract
Estimation of contaminant concentrations in earthworms is a critical component in many ecological risk assessments. Without site-specific data, literature-derived uptake factors or models are frequently used. Although considerable research has been conducted on contaminant transfer from soil to earthworms, most studies focus on only a single location. External validation of transfer models has not been performed. We developed a database of soil and tissue concentrations for nine inorganic and two organic chemicals. Only studies that presented total concentrations in depurated earthworms were included. Uptake factors and simple and multiple regression models of natural-log-transformed concentrations of each analyte in soil and earthworms were developed using data from 26 studies. These models were then applied to data from six additional studies. Estimated and observed earthworm concentrations were compared using nonparametricWilcoxon signed-rank tests. Relative accuracy and quality of different estimation methods were evaluated by calculating the proportional deviation ([measured - estimate]/measured) of the estimate from the measured value. With the exception of Cr, significant, single-variable (e.g., soil concentration) regression models were fit for each analyte. Inclusion of soil Ca improved model fits for Cd and Pb. Soil pH only marginally improved model fits. The best general estimates of chemical concentrations in earthworms were generated by simple ln-ln regression models for As, Cd, Cu, Hg, Mn, Pb, Zn, and polychlorinated biphenyls. No method accurately estimated Cr or Ni in earthworms. Although multiple regression models including pH generated better estimates for a few analytes, in general, the predictive utility gained by incorporating environmental variables was marginal.
Quadricyclane hydration kinetics in natural waters
Authors: Stauffer Thomas B , Antworth Christopher P , Burr Eila M , Macintyre William G 
Published: March 2010

Abstract
Hydration rates of quadricyclane were measured over a pH range of 3 to 8 in phosphate buffer, carbonate buffer, and nitric acid solutions. Norbornadiene was a minor impurity in the quadricyclane, and its hydration rate was also measured. Hydration products were exo−5-norbornen−2-ol (bicyclo[2.2.1]hept−5-ene−2-ol) and nortricyclyl alcohol (tricyclo[2.2.1.03,5]heptane−2-ol). Diol formation was not detected. Quadricyclane hydration in solutions containing chloride ions formed the alcohols and their chlorinated analogs. A mechanism consistent with observed kinetics and reaction products involving two carbocation intermediates is proposed. Comparison of reaction rates was used to determine the role of buffer catalysis and chlorination reactions in natural waters. Phosphate buffer catalysis was shown to be important, and rate constants for all phosphate species were calculated. Comparison of hydration rates in nitric acid and carbonate buffer indicated that catalysis by carbonate species for this reaction is unimportant in surface waters. Catalytic effects of other buffers in some natural waters appear possible. Proper buffer selection is important if laboratorymeasured hydration rates of quadricyclane are to be applied to natural water systems.
Ecotoxicological assessment of a recipient lake sediment of bleached—kraft pulping discharges
Authors: Suominen Kimmo P , Wittmann Christoph , Liukkonen Mikko , Kähkönen Mika A , Salkinoja—Salonen Mirja S 
Published: March 2010

AbstractWe assessed the biological status of age—dated sediments in Lake Saimaa, a recipient lake for wastewaters from pulp and paper industry for more than 100 years that has also received kraft pulp bleaching wastewater since 1954. Adenosine triphosphate content dropped in the recipient sediment from the top 1 cm (deposited in the 1990s) to 4 to 6 cm below the sediment surface (deposited in 1980s) by a factor of 1,000 but increased again in deeper, older layers (23 cm). The dominant species in the diatom community, Aulacoseira alpigena and Cyclotella kützingiana, disappeared and were replaced by Asterionella formosa in the 4- to 6-cm layer. This layer was three- to fivefold more toxic to Vibrio fischeri (as measured by the median effective concentration) and slightly genotoxic (as measured by the SOS—chromotest induction ratio, IC/I0 for Esherichia coli PQ37) compared with the layers above and below it. The 4- to 6-cm layer also contained up to 4,900 mg of solvent—soluble organic halogen (per kilogram of sediment dry weight). Enzyme activity (chitinase, phosphatase, α-glucosidase, and β-glucosidase) was detected at depths of 0 to 1 cm and 4 to 6 cm, and more than 90% of the enzymes were bound to the particulate matter. Ninety—seven percent of the organic halogen in the sediment was particle bound. Apparently, full ecological recovery occurred in the layer from 0 to 1 cm, which had accumulated in 1990s, after the discharging pulp mill discontinued use of Cl2 in the bleaching process and installed full—scale biological treatment for the wastewaters.
Kinetics of mixed function oxygenase induction and retene excretion in retene—exposed rainbow trout(Oncorhynchus mykiss)
Authors: Fragoso Nuno M , Hodson Peter V , Kozin Igor S , Brown R Stephen , Parrott Joanne L 
Published: March 2010

AbstractThe polycyclic aromatic hydrocarbon 7-isopropyl−1-methylphenanthrene (retene) induces mixed function oxygenase (MFO) activity of fish. Bile levels of retene and its metabolite(s) were measured in relation to exposure time, exposure concentration, and induction of MFO activity. Synchronous fluorescence spectrometry provided a rapid means of measuring the amount of retene present in the bile of exposed fish, whereas conventional fluorescence spectrometry was used to quantify the amount of retene metabolites. Based on bile analysis, increased retene exposure resulted in an increased uptake of retene and a curvilinear increase in hepatic MFO activity. Retene was present in the bile within 6 h of initial exposure. However, retene metabolite(s) only appeared in the bile after MFO induction had occurred, 12 h after exposure had commenced, suggesting that MFO activity is required for metabolism. Transfer of fish to clean water after 48 h of exposure resulted in a rapid decrease in the presence of retene and its metabolite(s) in the bile, with a calculated half—life of about 14 h. In vitro additions of retene directly to the ethoxyresorufin O-deethylase assay demonstrated that retene is capable of acting as a competitive inhibitor. Thus, retene contamination of postmitochondrial supernatant (S9 fraction) could result in false—negative results in the MFO assay. The MFO activity in extrahepatic tissues (gills, heart, and kidney) was not significantly induced with retene exposure. Thus, the major site of retene metabolism seems to be in the liver. These results confirm that retene is rapidly taken up, metabolized, and excreted by rainbow trout, and that retene metabolism and excretion are linked to hepatic MFO induction.
Dry deposition of atmospheric polycyclic aromatic hydrocarbons in three Plantago species
Authors: Bakker Martine I , Vorenhout Michel , Sijm Dick T.H.M. , Kollöffel Chris 
Published: March 2010

Abstract
The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leaf wax of three Plantago species were determined weekly for 3 weeks. The almost glabrous, free—standing leaves of Plantago major and the sparsely hairy Plantago lanceolata leaves were more heavily contaminated with low molecular weight (MW) PAHs (MW &lt; 228) than the densely hairy, partly overlapping Plantago media leaves. This may be caused by the lower canopy roughness (higher aerodynamic resistance), the higher amount of leaf hairs (higher boundary resistance), and/or the higher leaf overlap (smaller accessible leaf area) of P. media. On the other hand, PAHs with MW ≥ 252 tended to show higher concentrations in P. media than in the other two species. This is likely caused by the dense layer of hairs on P. media leaves, which can efficiently intercept the largely particle—bound high MW PAHs. When the PAH concentrations were normalized to projected leaf surface area, the differences between P. media and the other two species became significant (p &lt; 0.05) for the high MW PAHs, while the differences for the low MW PAHs decreased. Although the differences in PAH concentrations between species are relatively small (factor 2–5), this study clearly shows that plant architecture and leaf hairs influence the dry deposition of PAHs.
Accumulation and depuration of 2,3,7,8-tetrachlorodibenzofuran and octachlorodibenzo-p-dioxin by caddisfly larvae (Hydropsyche bidens(ross)) in miniature laboratory streams
Authors: Pastershank Georgine M , Muir Derek CG , Fairchild Wayne L 
Published: March 2010

AbstractThe uptake and depuration kinetics of [3H]−2,3,7,8-tetrachlorodibenzofuran ([3H]TCDF) and [14C]−1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin ([14C]OCDD) were studied in the filter—feeding caddisfly Hydropsyche bidens (Ross), using artificial laboratory streams. Dietary and water—borne routes of uptake were compared. Biomagnification factors (BMFs) ranged from 0.003 to 0.08 for TCDF and 0.003 to 0.007 for OCDD. The BMFs were significantly lower at higher exposure concentrations and for an earlier larval instar. Assimilation efficiencies for TCDF and OCDD were estimated to be 9.2 and 4.9%, respectively, based on an estimated feeding rate of 0.09 g/g body weight/d. Depuration of TCDF followed first—order kinetics with t1/2 ≥ 28 d. Depuration of OCDD was biphasic with an initial rapid t1/2 of &lt;2.9 d, followed by a slow rate of depuration. The initial rapid rate of depuration of OCDD could be explained by the loss of the gut contents. Depuration rates of TCDF and OCDD were not affected by a 33% increase in stream velocity from 16 to 24 cm/s or by changing contaminant concentrations in food. Nonfeeding caddisfly pupae accumulated approximately one tenth of the concentration of TCDF and OCDD that was accumulated by filter—feeding larvae under the same conditions. For the nonfeeding pupae, 10-d lipid—normalized bioconcentration factors for TCDF (1.0 3 105) were 10-fold higher than for OCDD (9.2 × 103).
Heavy metal content in liver and kidneys of grey seals (Halichoerus grypus) in various life stages correlated with metallothionein levels: Some metal—binding characteristics of this protein
Authors: Teigen, Sverre W , Andersen Rolf A , Daae Hanne Line , Skaare Janneche U 
Published: March 2010

Abstract
Liver and kidneys from grey seals (Halichoerus grypus) in their natural habitats in Norwegian waters contain high levels of Cd and Hg as well as metallothionein (MT). The data show significant placental transfer of heavy metals in seals. The MT concentrations were higher in fetus liver and kidneys than in the liver and kidneys of juveniles and adults. A significantly higher proportion of the total Cd and Cu, as compared to Zn and Hg, in fetal liver was associated with MT. Only low amounts of metals and MT were found in juveniles. In kidneys, little metal was associated with MT, although high amounts of Cd were bound in fetal stages. Positive correlations were found between total metal, MT content, and MT—bound metals, particularly for Cd and Zn. Grey seal MT may have higher affinity to Zn than to Cd. The use of seal MT as a biomarker for environmental heavy metal exposure seems promising.