bluuebunny/crossref_metadata_2025 huggingface dataset:
Reevaluation of general partitioning model for sorption of hydrophobic organic contaminants by soil and sediment organic matter
Authors: Leboeuf Eugene J , Weber Walter J
Published: March 2010

This evaluation of the polymer-based Flory–Huggins sorption theory has shown that the model predicts relatively concentration-independent χ values for rubbery matrices, concentration-dependent χ values for more glassy matrices, and highly concentration-dependent, largely negative interaction parameters for sorption of phenanthrene onto Green River kerogen, Ohio Shale II kerogen, Illinois No. 6 and Wyoming coals, and poly(phenyl methacrylate). These greatly negative enthalpic contributions to the interaction parameter are only to be expected where specific sorbate-sorbent interactions exist, such as in polar sorbate–polar sorbent systems. The failure of the nonlinear partitioning model is explained in terms of its inability to predict these increased interactions of sorbing solutes within microvoids present within glassy matrices. Calculations of sorbent solubility parameters through use of this model do, however, provide good agreement with literature solubility parameter values for specific sorbents; it may thus prove useful for partial characterization of sorbents for which solubility parameters are unknown.
Nonlinear and interactive effects in the sorption of hydrophobic organic chemicals by sediments
Authors: Jepsen Rich , Lick Wilbert
Published: March 2010

Long-term experiments were done in order to investigate nonlinear isotherms and interactive effects in the sorption of hydrophobic organic chemicals (HOCs) by sediments. In the isotherm experiments, it was demonstrated that the isotherms for all HOCs tested were linear as long as the mass of the sorbed HOC was small by comparison with the mass of organic carbon in the sediments; for larger sorbed HOC concentrations, the isotherms were nonlinear. Sorption experiments also were done with hexachlorobenzene (HCB)–octanol, HCB–ethanol, octanol–ethanol, and HOC–methanol mixtures in water and sediments. Interactive effects were observed and can be described in terms of the partitioning of the primary HOC between the cosolvent, water, and sediments.
Soil factors influencing atrazine sorption: Implications on fate
Authors: Novak Jeffrey M
Published: March 2010

The effects of two soil properties—soil organic carbon (SOC) content and landscape position—and a management factor (tillage) from Iowa and South Carolina soils on the sorption of the herbicide atrazine (6-chloro-N-ethyl-Nǐ-(1-methylethyl)-1,3,5-triazine-2,4-diamine) were evaluated to assess their influence on atrazine fate in the soil environment. In both Iowa and South Carolina, the magnitude of atrazine sorption was strongly and positively correlated with SOC, landscape position, and tillage. Landscape position was especially important for Iowa soils because SOC-enriched depressional areas (potholes) on the Wisconsin glacial surface could sorb more atrazine than soils in sloping positions. Our data suggest that herbicide management strategies such as application rates or herbicide selection will require some adjustments to account for the effects of SOC, landscape position, and tillage management on herbicide sorption in to augment effective weed control and prevent herbicide movement to groundwater.
Sorption and desorption rate comparisons for 1,2-dichlorobenzene to a peat soil
Authors: Deitsch James J , Smith James A
Published: March 2010

The rates of sorption and desorption were quantified for 1,2-dichlorobenzene to and from a peat soil using a batch methodology. Solute—sorbent contact times of 2, 7, 14, 49, and 99 d were studied for the desorption rate experiments. The experimental data were simulated using a distributed rate parameter model. The optimal model fitting parameters and their 95% confidence intervals were computed. The rates of desorption were significantly slower than the rate of uptake for solute–sorbent contact times greater than 2 d. For contact times greater than 2 d, a significant fraction of the 1,2-dichlorobenzene seemed to be irreversibly sorbed. However, the rate of desorption and the magnitude of the irreversible fraction were independent of contact time for contact times greater than 2 d. The rate observations for this study were consistent with an intraorganic matter diffusion mechanism.
Chemical and biological availability of sediment-sorbed hydrophobic organic contaminants
Authors: Lamoureux Elizabeth M , Brownawell Bruce J
Published: March 2010

The ability to predict accumulation levels of sediment-sorbed hydrophobic organic contaminants (HOCs) by depositfeeding organisms based on sediment concentrations is limited in part by an incomplete understanding of the chemistry that controls assimilation efficiency. This study was designed to test the hypothesis that desorption is an important process that controls the bioavailability of HOCs to deposit-feeding organisms; we planned to do so by conducting desorption and bioavailability experiments with field-contaminated sediments collected from New York Harbor, New York, USA. Three classes of organic contaminants, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and linear alkylbenzenes (LABs) were studied. In order to address the effects of contaminant aging, we compared the contaminant desorption rates from sediments collected from surface and at depth in an area of known high-sediment accumulation to retarded intraparticle model predictions. Measured desorption rates of the LABs and the most hydrophobic PCBs compare well with model predictions. However, the PAH and less hydrophobic PCB desorption rates range from one to four orders of magnitude slower than model predictions. We postulate that these compounds are present in a resistant sedimentary phase and may represent only a small fraction of what was originally sorbed. The fraction of PCBs, PAHs, and LABs desorbed after 48 h correlate well with measured biota-sediment factors (BSFs) in Yoldia limatula that were exposed to the same sediments, indicating that desorption rate-limited assimilation. Several studies have related field BSFs with log Kow and have observed a maximum at intermediate Kows (∼6.0-6.5). This maximum may be due to predictably slow desorption of high-Kow compounds and may be lower than predicted rates and extent of desorption of the low-Kow compounds because of association with resistant phases.
A behavioral toxicity test using the ciliated protozoan Tetrahymena thermophila. I. Method description
Authors: Gilron Guy , Gransden Scott G , Lynn Denis H , Broadfoot Jim , Scroggins Richard
Published: March 2010

A novel behavioral toxicity test using the ciliated protozoan Tetrahymena thermophila is described. Tests using a control water (spring water) and two reference toxicant solutions (sodium chloride and guaiacol) yielded reproducible results, indicating that the method has potential as a reliable toxicity test for use in industrial effluent monitoring.
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

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

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

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

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

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

Assimilation 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

The 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

A 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

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

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

We 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

The 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

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 < 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 < 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

The 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 <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

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.
Temperature—dependent, time–dose–effect model for pesticide effects on growing, herbivorous arthropods: Bioassays with dimethoate and cypermethrin
Authors: Akkerhuis Gerard AJM Jagersop , Kjær, Christain , Damgaard Christian , Elmegaard Niels
Published: March 2010

A toxicokinetics—based, temperature—dependent survival model for growing animals with oral uptake of toxicants is used to analyze the results of two pesticide bioassays. With this approach, we aim at simultaneously addressing two complementary goals of pesticide bioassays, namely to assess species sensitivity and to elucidate underlying mechanisms of toxic effects. As test organisms, newly hatched larvae of the chrysomelid beetle Gastrophysa polygoni L., dwelling on the underside of leaves of black bindweed Fallopia convolvulus (L.), kept at 12, 17, or 25°C were used. Plants with larvae were sprayed with dimethoate and cypermethrin at five dosages and a control. Survival was assessed during the following 6 d. The pesticide deposition pattern on the plants and the overall concentrations in the plants were determined. For dimethoate, which is mainly taken up orally, observed survival curves could be simulated successfully by the model. In the case of cypermethrin, which acts as a feeding deterrent, the model showed poor correspondence to the data. The significance of the results is discussed in relation to the test conditions and to toxicokinetics.
Irreversible binding of biologically reduced 2,4,6-trinitrotoluene to soil
Authors: Achtnich Christof , Sieglen Ute , Knackmuss Hans-Joachim , Lenke Hiltud
Published: March 2010

To analyze the fate of 2,4,6-trinitrotoluene (TNT) and its reduction products, a TNT-contaminated soil (350 mg TNT/kg dry soil) was spiked with [ring-UL−14C]TNT and treated in a laboratory slurry reactor. During an anaerobic/aerobic treatment, the total radioactivity measured in the supernatant and methanolic soil extracts decreased to 2%. The decrease corresponded to an increase of strongly bound radioactivity to the soil. Throughout the whole treatment process, mineralization of TNT was not observed. During the reductive process, unidentified polar substances increased to a maximum amount of 23.2% of the total radioactivity on the day after the start of the experiment. After the end of the anaerobic phase, still 9.7% of the radioactivity was found in this fraction. Only during the aerobic phase did the polar substances disappear completely. The irreversible character of the binding of the reduced metabolites of TNT to the soil was indicated by the failure of desorption even under rigorous and longterm extraction conditions. A significant release of radioactivity could be measured only by using high concentrations of HCI (5 N) or EDTA (12.5% and 5.9%, respectively). However, in none of the extracts were TNT or any reduced metabolites detected by HPLC and 14C-radiocounting. Size-exclusion chromatography of humic acids extracted from the treated soil indicated that the metabolites of TNT were evenly bound to the complete range of molecular size of the humic acids.
Alkylphenols, polycyclic aromatic hydrocarbons, and organochlorines in sediment from Lake Shihwa, Korea: Instrumental and bioanalytical characterization
Authors: Khim Jong Seong , Villeneuve Daniel L , Kannan Kurunthachalam , Lee Kyu Tae , Snyder Shane A , Koh Chul-Hwan , Giesy John P
Published: March 2010

Lake Shihwa is an artificial lake, located on the west coast of Korea, that has experienced environmental deterioration since 1994, when it was formed by construction of a sea dike. This study used instrumental analysis and in vitro bioassays to characterize organic contaminants in sediment collected from 11 stations on Lake Shihwa. Alkylphenol (AP) concentrations in Lake Shihwa sediment ranged from 20.2 to 1,820 ng/g nonylphenol and from 4.69 to 50.5 ng/g octylphenol, on a dry weight basis. Maximum concentrations of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, and polychlorinated biphenyls (PCBs) were 30.8, 2.26, and 12.3 ng/g (dry weight), respectively. Significant estrogenic activity was associated with fractions containing APs. Mass-balance analysis suggested that reported concentrations of APs account for less than 20% of the estrogenic activity observed. No significant dioxinlike activity was associated with fractions containing classic aryl hydrocarbon receptor agonists, such as PCBs, but the mid-polarity fractions containing PAHs and most polar fractions yielded significant dioxinlike activity. Overall, most of the in vitro bioassay responses appear to have been caused by unidentified and/or undetectable compounds associated with Lake Shihwa sediment.
Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (river Lot, France): I. Geochemical characteristics of the sampling sites and cadmium and zinc bioaccumulation kinetics
Authors: Andrès Sandrine , Baudrimont Magalie , Lapaquellerie Yvon , Ribeyre Francis , Maillet Noelle , Latouche Claude , Boudou Alain
Published: March 2010

Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic gradient in the river Lot (France), downstream from an old Zn ore treatment facility. The bivalves were held in benthic cages for a 5-month exposure period, April to September 1996; mollusk growth and metal bioaccumulation kinetics (Cd, Zn) were followed by subsampling the cages at t = 0, 21, 49, 85, 120, and 150 d. Rates of Cd bioaccumulation in the whole soft bodies and in individual organs were greater at the upstream stations located close to the pollution source, but there was no direct proportionality between Cd in the bivalves and in the unfiltered or filtered river water samples. Unlike the case for Cd, rates of Zn bioaccumulation did not reflect the contamination gradient. Marked growth differences were measured among the four stations, reflecting both nutritional differences and changes in the degree of metal contamination; these growth differences produced markedly different trends when metal bioaccumulation was expressed in terms of burdens rather than concentrations.
Polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in tree swallows from the upper Hudson River, New York State, USA
Authors: Secord Anne L , McCarty John P , Echols Kathy R , Meadows John C , Gale Robert W , Tillitt Donald E
Published: March 2010

The upper Hudson River of New York State, USA, is contaminated with polychlorinated biphenyls (PCBs) as a result of industrial discharges throughout the latter half of this century. In 1994 and 1995, we monitored the transfer of PCBs from aquatic sediments to a terrestrial wildlife community using the tree swallow (Tachycineta bicolor) as a model organism. Tree swallow eggs and nestlings were collected at four colonies established along a 40-km stretch of the upper Hudson River watershed. Samples were analyzed for total PCBs and PCB congeners, including non-ortho- and mono-ortho-substituted PCBs. Mean concentrations of PCBs in tree swallow eggs and nestlings ranged from 721 to 62,200 ng/g and were as much as 15 times greater than PCB concentrations in tree swallow eggs and nestlings collected from PCB-contaminated areas within the Great Lakes ecosystem. The corresponding 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) calculated using avian toxic equivalency factors ranged from 410 to 25,400 pg/g. Concentrations of PCB congener 77 (3,39,4,49-tetrachlorobiphenyl) were extremely elevated and were major contributors to the calculated TEQs. Homologue pattern comparisons between Hudson River and Saginaw River (Michigan, USA) ecosystems supported the hypothesis that a consistent Hudson River PCB source was the major contributor to PCBs in Hudson River tree swallows. The high concentrations of PCBs in Hudson River sediments and resultant concentrations observed in tree swallows were indicative of a potential elevated risk to these and other wildlife linked to the aquatic food web of the Hudson River ecosystem.
Predicting stress in benthic communities of southeastern U.S. estuaries in relation to chemical contamination of sediments
Authors: Hyland Jeffrey L , Van Dolah Robert F , Snoots Timothy R
Published: March 2010

Matching data on sediment contaminants and macroinfaunal community structure from 231 subtidal stations in southeastern U.S. estuaries were used to develop a framework for evaluating risks of benthic impacts from multiple-contaminant exposure. Sediment contamination was expressed as the mean ratio of individual contaminant concentrations relative to corresponding sediment quality guidelines, that is, to effects range-median (ERM) values, probable effects level (PEL) values, or an aggregate of the two. The probability of a degraded benthos was relatively low in samples with mean ERM quotients ≤0.020, PEL quotients ≤0.035, or combined ERM/PEL quotients ≤0.024. Only 5% of stations within these ranges had degraded benthic assemblages, while 95% had healthy assemblages. A higher probability of benthic impacts was observed in samples with mean ERM quotients >0.058, PEL quotients >0.096, or ERM/PEL quotients >0.077. Seventy-three to 78% of stations with values in these upper ranges had degraded benthic assemblages, while 22 to 27% had healthy assemblages. Only four stations (three with degraded, one with healthy assemblages) had mean ERM or PEL quotients >1.0, which is the beginning of the range associated with a high probability of mortality in short-term laboratory toxicity tests using amphipods.
Concentrations of 17 elements in the zebra mussel (Dreissena polymorpha), in different tissues of perch (Perca fluviatilis), and in perch intestinal parasites (Acanthocephalus lucii) from the subalpine lake Mondsee, Austria
Authors: Sures Bernd , Steiner Werner , Rydlo Manfred , Taraschewski Horst
Published: March 2010

Concentrations of the elements Al, Ag, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Tl, and Zn were analyzed by inductively coupled plasma mass spectrometry in the acanthocephalan Acanthocephalus lucii (Müller); in its host, Perca fluviatilis (L.), and in the soft tissue of the zebra mussel, Dreissena polymorpha (Pallas). All animals were collected from the same sampling site in a subalpine lake, Mondsee, in Austria. Most of the elements were found at significantly higher concentrations in the acanthocephalan than in different tissues (muscle, liver, and intestinal wall) of its perch host. Only Co was concentrated in the liver of perch to a level that was significantly higher than that found in the parasite. Most of the analyzed elements were also present at significantly higher concentrations in A. lucii than in D. polymorpha. Barium and Cr were the only elements recorded at higher concentrations in the mussel compared with the acanthocephalan. Thus, when comparing the accumulation of elements, the acanthocephalans appear to be even more suitable than the zebra mussels in terms of their use in the detection of metal contamination within aquatic biotopes. Spearman correlation analysis revealed that the concentrations of several elements within the parasites decreased with an increasing infrapopulation. Furthermore, the levels of some elements in the perch liver were negatively correlated with the weight of A. lucii in the intestine. Thus, it emerged that not only is there competition for elements between acanthocephalans inside the gut but there is also competition for these elements between the host and the parasites. The elevated element concentrations demonstrated here in the parasitic worm A. lucii provide support for further investigations of these common helminths and of their accumulation properties.
Reproductive success and behavior of Japanese medaka (Oryzias latipes) exposed to 4-tert-octylphenol
Authors: Gray Michelle A , Teather Kevin L , Metcalfe Chris D
Published: March 2010

Japanese medaka (Oryzias latipes), a small freshwater fish used extensively to investigate sexual differentiation and development, were exposed to octylphenol (OP), a known estrogen agonist, to assess its impact on reproductive success. Male and female medaka were exposed to nominal concentrations of 10, 25, 50, and 100 μg/L OP from 1 d posthatch to 6 months posthatch. In reproduction trials involving exposed males and unexposed females, the males exposed to nominal concentrations of 25 and 50 μg/L showed a reduction in some courtship activity and overall reproductive success. Eggs produced by matings of exposed males and females demonstrated various developmental problems, including circulatory system difficulties, incomplete eye development (i.e., anisophthalmia), and failure to inflate swim bladders upon hatch. One male fish with an intersex gonad was able to fertilize the eggs of an unexposed female. This study is one of the first to show the possible behavioral and transgenerational effects of an estrogenic compound on the reproductive success and second generation embryo-larval development of fish.
Evaluating the techniques for a tiered testing approach to dredged sediment assessment—a study over a metal concentration gradient
Authors: Porebski Linda M , Doe Kenneth G , Zajdlik Barry A , Lee Deanna , Pocklington Patricia , Osborne James M
Published: March 2010

A sediment quality triad approach was used to evaluate Environment Canada's battery of marine bioassays and the proposed pass/fail criteria along a metals gradient in Belledune Harbour, New Brunswick, Canada. Most assays performed consistently, but certain tests provided less response than expected at the more contaminated stations (amphipod survival and light reduction in photoluminescent bacteria tests passed according to proposed pass/fail criteria). Echinoid fertilization tests were quite sensitive. Bioaccumulation of lead and benthic community structure were related to bulk sediment values (at α = 0.1). Test interpretation criteria appear reasonable, but as the response rate was low in certain tests, further assessment is recommended. With respect to species suitability, only the clam Macoma balthica used in the bioaccumulation test was thought to be less than optimal for routine use on a large scale because of practical handling and cost considerations. Canadian draft Interim Sediment Quality Guidelines, which the Disposal at Sea Program may use for screening purposes in a tiered testing approach, were used in this study as the chemical benchmarks to select test stations on the basis of the relative probability of effects. Guidelines at the threshold effects level (TEL) performed well in the study as levels below which unacceptable biological effects were unlikely to occur. The ratio of simultaneously extractable metals to acid volatile sulfides was also used in addition to the guideline levels to help explain responses (or lack thereof) along the gradient. Each of the chemical approaches was useful in the prediction/explanation of some but not all of the responses seen in the toxicity and/or benthic community results.
Predicted no-effect concentrations and risk characterization of four surfactants: Linear alkyl benzene sulfonate, alcohol ethoxylates, alcohol ethoxylated sulfates, and soap
Authors: van de Plassche Erik J , de Bruijn Jack H M , Stephenson Richard R , Marshall Stuart J , Feijtel Tom C J , Belanger Scott E
Published: March 2010

Assessment of aquatic effects requires the derivation of a predicted no-effect concentration (PNEC). In the framework of the Dutch “Plan of Action Laundry and Cleaning Products,” PNECs were derived for linear alkyl benzene sulfonate (LAS), alcohol ethoxylates (AE), alcohol ethoxylated sulfates (AES), and soap. All stages in an aquatic effects assessment were used: initial (assessment factors based mainly on short-term toxicity data), refined (statistical extrapolation based on long-term toxicity data), and comprehensive (field studies). Where necessary (i.e., where other structures had been tested in toxicity tests), the toxicity data were normalized to these structures using quantitative structure-activity relationships (QSARs) for short-term toxicity. Results from statistical extrapolation were compared with field no observed effect concentrations (NOECs), and a final PNEC was derived. Final PNECs for LAS, AE, AES, and soap were 250, 110, 400, and 27 μg/L, respectively. These PNECs were compared with predicted environmental concentrations (PECs) in surface water that were derived from monitoring results of removal of these surfactants in seven representative wastewater treatment plants. It is concluded that for LAS, AE, and AES, the PECs in the environment are about 50 to 100 times lower than the PNECs. The PEC for soap is about equal to the PNEC that is based on acute toxicity data. However, because the available chronic toxicity data for soap demonstrate that this substance is not more toxic than the other three surfactants, there is no reason for concern. On the basis of the results of the risk characterization, it has been concluded in the Netherlands that in properly functioning wastewater treatment plants, the risks for the aquatic compartment from the use of LAS, AE, AES, and soap are low.