bluuebunny/crossref_metadata_2025 huggingface dataset:
Equilibrium partitioning and bioaccumulation of sediment-associated contaminants by infaunal organisms
Authors: Lake James L. , Rubinstein Norman I. , Lee Henry , Lake Carol A. , Heltshe James , Pavignano Sharon
Published: March 2010

The utility and limits of applicability of a simple equilibrium partitioning model for predicting the maximum concentration of neutral organic compounds which can be accumulated by infaunal organisms exposed to a contaminated sediment were examined. Accumulation factors (AFs) for PCBs, the lipid normalized PCB concentration in organisms divided by the organic carbon normalized PCB concentration in sediments, were measured for PCBs in infaunal mollusks and polychaetes at field sites with a range of sediment Aroclor (A-1254) and total organic carbon (TOC) concentrations. The average AFs for A-1254 were found to be higher (x̄ = 4.94; range 3.76–7.27) at sites with lower contaminant concentrations (15.0–48.3 ng A-1254/g dry sediment) than at more contaminated sites (328–9,200 ng/g), where AFs were lower (x̄ = 2.62; range 1.14–5.04). AF data grouped on the basis of sediment A-1254 and TOC concentration differed statistically between, but not within each group. Significant differences in mean AFs were found between some species and between some PCB congeners. When all data were considered, the variability associated with AFs was lower than that found for bioaccumulation factors on a wet weight basis, indicating the utility of lipid and organic carbon normalization.
Slowly reversible sorption of aliphatic halocarbons in soils. I. Formation of residual fractions
Authors: Pignatello Joseph J.
Published: March 2010

This study describes the formation of slowly reversible sorbed fractions of various halogenated alkanes and alkenes in two surface soils. After the initial sorption equilibration period, the compounds were desorbed by one of two methods. The first used repetitive batch extraction with water. After 16 extractions of 24 to 72 h each, concentrations in the aqueous phase reached low values and a slow desorbing, residual fraction remained in the soil. The residual fraction in the soil was determined independently after extraction with hot acetone, whose efficacy was demonstrated. During desorption, apparent soil-water distribution coefficients increased progressively to as much as 200 times greater than equilibrium sorption coefficients, Kd, obtained separately from sorption isotherms. With increasing sorption equilibration time, the residual became greater in magnitude and less mobile. The second desorption method simulated desorption to infinite dilution over a 96 h period by using Tenax GC polymeric adsorbent beads included in the suspension as a sink for desorbed chemical. Control experiments proved the usefulness of Tenax and showed that desorption from the soil was rate limiting. All compounds studied formed slowly reversible fractions in the soils. This fraction amounted to several percent of the total sorbed from solution. The results indicate that formation of slowly reversible fractions is probably typical of nonpolar organic compounds, including those with weak sorbing tendencies.
The stage specific toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in embryos of the japanese medaka (Oryzias latipes)
Authors: Wisk Joseph D. , Cooper Keith R.
Published: March 2010

Embryos of the Japanese medaka were individually exposed to varying concentrations of [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in a static, nonrenewal system. The EC50 with 95% confidence interval (C.I.) to prevent hatching was 14 (11–17) nanograms (ng) of TCDD equivalents per liter (L) of water (parts per trillion). The LC50 with 95% C.I. for survival to 3 d posthatch was 9 (6–12) ng TCDD equivalents/L. The EC50 with 95% C.I. for embryos with minor lesions and severe, life-threatening lesions were 3.5 (1.3–5.7) ng TCDD equivalents/L and 14 (12.4–15.6) ng TCDD equivalents/L, respectively. In a separate experiment that was terminated prior to the embryos hatching or dying, the EC50 for lesions was calculated to be 2.2 (1.4–3.0) ng TCDD equivalents/L. Based on the amount of TCDD equivalents recovered from dechorionated embryos, the ED50 with 95% C.I. for lesions was calculated to be 0.24 picograms of TCDD equivalents per milligram of dechorionated embryo weight (parts per billion). When the embryos were exposed to [3H]TCDD within 1 to 2 h after fertilization, no concentration dependent increase in visible lesions was observed until after the formation of the liver rudiment (day 4 of development). By exposing Japanese medaka embryos to lethal concentrations of TCDD beginning on different days of embryonic development, it was demonstrated that the sensitive period for toxicity was during liver formation on day 4 or 5 of development. The sensitive period for development was not caused by differences in TCDD absorption across the chorion. When embryos were exposed to [3H]TCDD prior to, during or after liver formation, there was no statistical difference in the dose of TCDD equivalents that crossed the chorion and entered the yolk and embryo.
Monitoring linear alkyl benzene sulfonate in the environment: 1973–1986
Authors: Rapaport R.A. , Eckhoff W.S.
Published: March 2010

Results from extensive monitoring from 1973 to 1986 indicate that linear alkyl benzene sulfonate (LAS) is extensively removed by sewage treatment with resulting river water concentrations in the low ppb range. Wastewater treatment plant removal efficiencies exceed those for biochemical oxygen demand (BOD); they average 98% for activated sludge, 80% for trickling filters and 27% for primary clarification. Concentrations in influent sewage (x̄ = 3.5 mg/L), effluent sewage (x̄ = 0.06–2.1 mg/L), and in river waters (<0.005–0.3 mg/L) are in agreement with predicted concentrations and measurements by other investigators. Levels of LAS in soil cores analyzed shortly after sludge amendment range from <3 to 47 mg/kg and are consistent with sludge loading rates and biodegradation of LAS from the previous year's sludge application. Removal of LAS occurs by biodegradation in all compartments and sorption/settling from the water column. Longer chain length, more sorptive LAS homologs are relatively enriched in sludge solids and in river sediments, thus the average LAS chain length was found to be higher in those compartments. Results obtained from long-term monitoring support the rapid removal of LAS by biodegradation in the environment.
A remote in situ apparatus for ambient toxicity testing of larval and yearling fish in river or estuarine systems
Authors: Ziegenfuss Michael C. , Hall Lenwood W. , Bushong Steven J. , Sullivan John A. , Unger Michael A.
Published: March 2010

A remote in situ apparatus for ambient toxicity testing of prolarval and yearling striped bass, Morone saxatilis, was designed and tested in the upper Chesapeake Bay and Potomac River during the 1989 spawning season. The apparatus' design, capabilities and significance in environmental monitoring are discussed.
Biological transformations of 1,1,1-trichloroethane in subsurface soils and ground water
Authors: Klečka Gary M. , Gonsior Stanley J. , Markham Daniel A.
Published: March 2010

1,1,1-Trichloroethane was readily degraded in samples from an alluvial aquifer under both methanogenic and sulfate reducing conditions. No lag period was noted prior to disappearance of the parent compound. Products detected in the reaction mixtures included 1,1-dichloroethane, chloroethane, 1,1-dichloroethene, acetic acid and carbon dioxide. No other chlorinated metabolites were detected. Biological reductive dehalogenation was responsible for the metabolism of 1,1,1-trichloroethane to 1,1-dichloroethane and to chloroethane. Abiotic transformations resulted in 1,1-dichloroethene and acetic acid. However, biological mechanisms also appeared to contribute to the formation of acetic acid, which was subsequently mineralized to carbon dioxide. Pseudofirst-order rate constants estimated for the biotransformation of 1,1,1-trichloroethane were in the range of 0.0034 day−1 to 0.015 day−1, whereas the rate constant for abiotic degradation was approximately 0.0006 day−1. Biotransformation of the compound was not observed in aquifer samples under aerobic or denitrifying conditions.
Investigation of preference-avoidance responses to an oil refinery effluent with striped bass and steelhead trout
Authors: Carr Robert Scott , Barrows Michael E. , Reichenbach Norman G. , DeGraeve G. Michael , Pollock Terry L. , Fava James A. , Glickman Andrew H.
Published: March 2010

Preference-avoidance tests using a modified Y-maze test apparatus were conducted with juvenile striped bass, Morone saxatilis, and steelhead (rainbow) trout, Oncorhynchus mykiss (formerly Salmo gairdneri), exposed to a refinery effluent discharged into San Francisco Bay. The test system was set up on site at the refinery, and the performance of the test system was validated using two reference materials, phenol (reference avoidant) and a mixture of amino acids (which was hoped would serve as a reference attractant). Both species of fish were tested at four effluent concentrations ranging from 0.1 to 10% with two different dilution waters, the receiving water and a known high-quality natural seawater. The results of this study indicate that juveniles of both species tended to avoid the effluent at concentrations that might be expected to occur within a short distance of the refinery outfall diffuser. At concentrations that would occur outside the zone of initial dilution, neither species of fish exhibited a preference or avoidance response to the refinery effluent.
Direct in situ sensing of the fugacity of hydrophobic chemicals in natural waters
Authors: Sproule J. W. , Shiu W. Y. , Mackay D. , Schroeder W. H. , Russell R. W. , Gobas F. A. P. C.
Published: March 2010

Two sparging devices have been designed, built, and tested. They can be used to estimate the concentration of truly dissolved chemical in water and thus the potential for diffusive transfer by volatilization. Samples of air, and air contacted to achieve equilibrium with the water, are analyzed to give an unequivocal determination of the displacement of equilibrium between air and water. Essentially, the chemical's fugacity or partial pressure is measured. A theoretical treatment is presented. Exploratory test results in a wind-wave tank and in the field are described and discussed. It is believed that these devices are of value for assessing the sorbed vs. dissolved condition of hydrophobic chemicals in natural waters that influences not only volatilization but also other diffusive processes such as bioconcentration.
Use of respiratory-cardiovascular responses of rainbow trout (Oncorhynchus mykiss) in identifying acute toxicity syndromes in fish: Part 4. Central nervous system seizure agents
Authors: Bradbury Steven P. , Carlson Richard W. , Niemi Gerald J. , Henry Tala R.
Published: March 2010

The respiratory-cardiovascular responses of spinally transected rainbow trout to acutely lethal concentrations of chlorpyrifos, cypermethrin, fenvalerate, endosulfan, endrin, and strychnine were examined. Common to all six toxicants, the most striking change in respiratory-cardiovascular parameters was an increased cough frequency. Ventilation frequency and volume dropped in strychnine-exposed trout, but both remained near predose levels (frequency) or elevated (volume) in the pyrethroid- and cyclodiene-exposed trout. In chlorpyrifos-intoxicated trout, ventilation frequency decreased while volume increased. Oxygen consumption remained near predose levels in the chlorpyrifos-, pyrethroid-, and strychnine-exposed trout, but increased dramatically in the cyclodiene-exposed trout. Arterial oxygen, carbon dioxide, and pH declined in all the toxicant groups. In the pyrethroid- and strychnine-exposed trout, hematocrit and hemoglobin levels tended to increase or remain constant during intoxication. Conversely, in the chlorpyrifos- and cyclodiene-exposed trout, values for these parameters decreased. The responses for these pesticides (N= 23 fish) were combined with five fish acute toxicity syndromes (FATS) (N = 52 fish) previously described (non-polar narcosis syndrome, polar narcosis syndrome, acetylcholinesterase inhibitor syndrome, respiratory uncoupler syndrome, and respiratory irritant syndrome) and assessed using discriminant function analyses. The final analysis resulted in 93% correct classification of the trout.
Multibiological-level responses of freshwater phytoplankton to pesticide stress
Authors: Kent Robert A. , Weinberger Pearl
Published: March 2010

Axenic batch cultures of freshwater algae were used to study the molecular, cellular and population effects of the organophosphorus insecticide fenitrothion on freshwater phytoplankton. The unicellular chlorophytes Chlamydomonas segnis, Chlorella pyrenoidosa, Scenedesmus obliquus, Ankistrodesmus falcatus and Selenastrum capricornutum were exposed to three treatment levels (0.1, 1.0 and 10.0 mg/L) of fenitrothion. The monitored response parameters represent three levels of biological organization and included total cellular protein, carbohydrate, RNA and DNA levels, cell dry weight, cell volume, growth estimates and cell size distribution. Growth curves revealed differential algistasis among the species following 24 h exposure to fenitrothion, with induction of an extended lag phase in all cases. Levels of 10.0 mg/L elicited reductions in the maximum growth rate and standing crop of up to 62 and 96%, respectively. Biomolecular indicators of phytotoxicity were manifested in the significant augmentation of macromolecular fractions. This biochemical accrual together with elevated dry weight and reduction in cell density was a common response pattern. It was postulated that fenitrothion prevented normal mitotic divisional processes from occurring. Uninhibited biomolecular synthesis resulted in an accumulation of macromolecules and subsequent cell weight augmentation. Modal cell volumes increased and normalized cell distribution spectra displayed a shift toward larger cells in treated algal populations.
Toxicity of trimethyltin and triethyltin to mallard ducklings
Authors: Fleming W. James , Hill Elwood F. , Momot Jeffrey J. , Pang Victor F.
Published: March 2010

Trimethyltin chloride (TMTC) and triethyltin chloride (TETC) were fed to mallard (Anas platyrhynchos) ducklings for 73 to 75 d, beginning when ducklings were 3 to 4 d old. Diets were mixed to contain 0, 0.5, 5 or 50 ppm Sn as either TMTC or TETC. Mortality occurred only in the 5 ppm (2/5 ducklings) and 50 ppm (5/5 ducklings, all dying within 5 d) TMTC groups. Death was preceded by cephalic tremors, lethargy and ataxia; these clinical signs also were observed in surviving ducklings from the 5 ppm TMTC group, but not the 0.5 ppm TMTC group. Ducklings fed 5 and 50 ppm Sn as TMTC exhibited degeneration of the large neurons of the pons, medulla oblongata, gray matter of the spinal cord and pyramidal cells of the cerebral cortex. TETC-fed ducklings showed few signs of clinical toxicosis. Ducklings fed 50 ppm Sn as TETC exhibited mild to severe vacuolization of the white matter of the brain and spinal cord; these lesions were not present in ducklings fed 5 ppm Sn as TETC. Liver, spleen, kidney, thymus, bursa of Fabricius and skeletal muscle presented no abnormal histopathology for either organotin compound. Hematocrit, hemoglobin and plasma aspartate aminotransferase; alanine aminotransferase; lactate dehydrogenase; alkaline phosphatase; and cholinesterase values were determined for the 5- and 50- ppm TMTC and TETC groups, and were not different from those of controls (p < 0.05). Lesions and clinical signs of toxicosis in ducklings were consistent with those described for mammals exposed to TMTC and TETC. The effect threshold for TMTC in ducklings appears to exceed current environmental concentrations. Environmental concentrations of TETC have not been reported.
Evaluation of effects associated with an oil platform, using the sediment quality triad
Authors: Chapman P. M. , Power E. A. , Dexter R. N. , Andersen H. B.
Published: March 2010

The Sediment Quality Triad concept, which incorporates components of sediment chemistry, toxicity (= bioassay tests) and benthic community structure, was applied to the area immediately surrounding a commercial oil and gas production site in the Gulf of Mexico. The results of this study indicated that stations within a 25-m radius of a central platform and at a remote platform had high levels of sediment chemical enrichment and high toxicity, as determined in laboratory sediment toxicity tests. Benthic community structure at those stations was different from that at more distant stations, where chemical enrichment and toxicity were low; the differences included some examples of greater taxa richness, total abundance and specific taxa abundance in the vicinity of the platforms. There was no evidence of depauperate fauna near the platforms, such as might be expected if significant adverse effects were manifest in situ. Although chemical enrichment from the platforms had the potential to cause adverse environmental effects within the immediate vicinity of source (the 25-m stations in the present study), this potential was not manifest in the benthos, possibly due to offsetting factors that could have included the physical habitat provided by the platforms, grain-size effects and adaptation.
Structure-activity relationships for osteolathyrism: IV. Para-substituted benzoic acid hydrazides and alkyl carbazates
Authors: Dawson Douglas A. , Schultz T. Wayne , Baker Leslie L.
Published: March 2010

Nine benzoic acid hydrazides and carbazates were assayed for toxicity and teratogenicity by using early embryos of the frog Xenopus laevis. The results of the 96-h static tests were used for quantitative structure-activity relationship (QSAR) analyses. Each compound induced the connective tissue defect osteolathyrism. Regression analyses indicated toxicity (LC50) and teratogenicity (EC50) were best correlated with the STERIMOL width parameter B1, but due to redundancy in B1 values for the test chemicals and the relatively low r2 for the models, those equations should be used with caution. The mortality/malformation index (MMI) was negatively correlated with molar refractivity (MR). The relationships indicate that steric interactions may be important in explaining the variation in biological activity due to changes in chemical structure. Frog embryo teratogenesis assay: Xenopus (FETAX) may be useful in aquatic toxicology hazard assessment, evaluating developmental malformation.
The contribution of ammonia, metals and nonpolar organic compounds to the toxicity of sediment interstitial water from an illinois river tributary
Authors: Schubauer-Berigan Mary K. , Ankley Gerald T.
Published: March 2010

Toxicity of Illinois River bulk sediment, sediment interstitial (pore) water and elutriates to the oligochaete Lumbriculus variegatus, fathead minnow (Pimephales promelas) and the amphipod Hyalella azteca was compared to determine the most representative aqueous fraction for toxicity identification evaluation (TIE) studies. Toxicity of pore water corresponded better than elutriates to bulk sediment toxicity. Subsequent TIE procedures conducted with the cladoceran Ceriodaphnia dubia indicated that ammonia, metals and nonpolar organic compounds (nonylphenols, polycyclic aromatic hydrocarbons, benzenes, long-chain hydrocarbons) were responsible for toxicity of the sediment pore water. Results of TIE manipulations also suggested that methods for recovering pore water that include filtration may eliminate, a priori, a major component of the sediment contaminants responsible for toxicity.
A sediment bioassay using the tubificid oligochaete worm Tubifex tubifex
Authors: Reynoldson Trefor B. , Thompson Sherri P. , Bamsey Jennifer L.
Published: March 2010

A new technique using the tubificid oligochaete Tubifex tubifex as a standard sediment bioassay is described. The various factors affecting quality assurance and control have been examined, such as the appropriate number of replicates; the sensitivity, discriminatory power, and repeatability of the test; and the effects of temperature, animal size, organic content, density, and duration on the test. The proposed bioassay is simple and straightforward and can be done with readily available and inexpensive equipment. It utilizes reproduction, the most ecologically relevant and sensitive life stage, as an end point and has been shown in the laboratory to be both repeatable and discriminatory. The technique can be recommended for further investigation in field trials and for consideration as part of a suite of assays for use in sediment assessment.
The acute and chronic toxicity of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to three freshwater invertebrates
Authors: Peters Gregory T. , Burton Dennis T. , Paulson Robert L. , Turley Steven D.
Published: March 2010

The acute and chronic toxicities of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to adaphnid (Ceriodaphnia dubia), a hydra (Hydra littoralis), and a midge (Paratanytarsus parthenogeneticus) were examined. RDX concentrations at the solubility limit of the compound under specific test conditions (17.0 mg RDX/L, Ceriodaphnia dubia at 25°C; 32.3 mg RDX/L, Hydra littoralis at 22°C; and 29.2 mg RDX/L, Paratanytarsus parthenogeneticus at 22°C) were not acutely toxic to any of the three tested invertebrates. In a 7-d survival and reproduction test with Ceriodaphnia dubia, RDX caused no significant effect on survival, but reduced reproductive success. The no-observed-effect concentration, lowest-observed-effect concentration, and chronic value for Ceriodaphnia dubia were 3.64, 6.01, and 4.68 mg/L, respectively. In an egg-to-egg life cycle test with Paratanytarsus parthenogeneticus, survival, growth, egg production, and hatching success were unaffected by RDX. Although not statistically significant, reductions in emergence success were observed at concentrations as low as 6.78 mg/L.
Inhibition of alcohol dehydrogenase activity by acetylenic and allylic alcohols: Concordance with in vivo electrophile reactivity in fish
Authors: Bradbury Steven P. , Christensen Glenn M.
Published: March 2010

Acetylenic and allylic alcohols have been reported to be 20 to 5,000 times more acutely toxic to fathead minnows (Pimephales promelas) than would be expected from a narcosis-based mechanism of action. The greater-than-expected toxicity of these alcohols has been proposed to be a result of metabolic activation to the corresponding reactive α,β-unsaturated aldehydes or allene derivatives. Using purified horse liver and rainbow trout (Oncorhynchus mykiss) hepatic cytosol alcohol dehydrogenase (ADH) preparations, the propensity of a series of acetylenic and allylic alcohols to inhibit enzyme activity, in both the presence and the absence of reduced glutathione, was ascertained. Those alcohols classified as reactive toxicants in acute toxicity tests were generally effective inhibitors of ADH activity, whereas those alcohols classified as narcotics were generally ineffective inhibitors. The results from this study suggest that (a) acetylenic and allylic alcohols may be metabolically activated to reactive species and (b) to compare and ultimately predict the toxicity of these unsaturated alcohols, their rates of metabolic activation and the reactivity of the subsequently produced aldehydes must be quantified.
A statistical bias in the derivation of hardness-dependent metals criteria
Authors: Newman Michael C.
Published: March 2010

Log-transformed values of lethal effect and hardness are often employed to predict metal effects. For example, they are used to develop water quality criteria. A statistical bias encountered with backtransformed, least-squares regression models can compromise the accuracy of associated predictions. A description and method of estimating this bias are discussed herein. In a selected data set, the bias was as high as 57%.
Xenobiotic compounds in blue crabs from a highly contaminated urban subestuary
Authors: Mothershead Robert F. , Hale Robert C. , Greaves John
Published: March 2010

Blue crabs (Callinectes sapidus), collected from the industrialized Elizabeth River, Virginia, contained residues of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides. The Elizabeth River possesses PAH sediment loadings that are among the highest ever reported. Despite these loadings, commercial fishing for blue crabs continues in this river. Muscle and hepatopancreas from the crabs were analyzed for the xenobiotic compounds. Analytical procedures involved dichloromethane extraction of lyophilized tissue, followed by molecular size and polarity-based purification of the extract. Capillary gas chromatography with flame ionization and electrolytic conductivity detection was used for quantitation and tentative identification of the xenobiotic compounds. Mass spectrometry was used for confirmation of these identities. Contaminant concentrations were greater in hepatopancreas than in muscle in crabs from every site examined. Hepatopancreas PAH burdens were as high as 11 mg/kg dry weight, with an accompanying muscle level of 3.1 mg/kg. The PAHs present consisted mainly of alkylated low-molecular-weight compounds (e.g., acenaphthenes and naphthalenes), except near a creosote-impacted site. At the latter location, unsubstituted, higher-molecular-weight PAHs (e.g., pyrene and chrysene) dominated. Organochlorines, which included PCBs, 4,4′-DDE, and chlordane, were found in lower concentrations.
Predicting the toxicity of bulk sediments to aquatic organisms with aqueous test fractions: Pore water vs. elutriate
Authors: Ankley Gerald T. , Schubauer-Berigan Mary K. , Dierkes Joseph R.
Published: March 2010

The objective of this research was to evaluate the acute toxicity of bulk sediment vs. pore water or elutriate to fathead minnows (Pimephales promelas), cladocerans (Ceriodaphnia dubia), amphipods (Hyalella azteca), and oligochaetes (Lumbriculus variegatus). A total of 29 different samples from seven sites were used for this analysis. In most instances, pore water was more toxic than corresponding elutriate. Based on the results of these assays, pore water, but not elutriate, was an effective test fraction for predicting the presence of bulk sediment toxicity; however, there were a number of observations of pore water toxicity in the absence of bulk sediment toxicity. Data from this study concerning the sensitivity of Pimephales promelas, Hyalella azteca, and Lumbriculus variegatus to bulk sediment vs. pore water or elutriate suggest that upper-water-column species are inappropriate organisms for use in bulk sediment tests focused on evaluating in situ toxicity to benthic species. Hyalella azteca was the most sensitive and Lumbriculus variegatus the least sensitive species evaluated.
Solid-phase extraction of carbaryl and malathion from pond and well water
Authors: Beyers Daniel W. , Carlson Clarence A. , Tessari John D.
Published: March 2010

An analytical method was developed using C8 solid-phase extraction columns to extract carbaryl and malathion from well and pond water. Mean percent recovery over a concentration range of 1 μg/L to 10,000 μg/L was consistently between 80 and 100. Well-water samples fortified with carbaryl and malathion were solid-phase extracted, and analytes were stored on solid-phase extraction columns at —4°C for 30 d without significant decomposition. The method was field-tested by collecting pond water before and after an application of malathion. It provided significantly higher recovery of malathion than a liquid-liquid extraction procedure.
Effects of dissolved humic material on the toxicity of selected pyrethroid insecticides
Authors: Ortego Lisa S. , Benson William H.
Published: March 2010

The effect of different sources of dissolved humic material on the acute toxicity of the pyrethroid insecticides fenvalerate (Pydrin®) and permethrin (Ambush®) was examined by using the Microtox® bioassay. Toxicity of the insecticides was examined in the presence of commercially available humic acid (HA) as well as aquatic HA and fulvic acid (FA) at concentrations of 0, 0.5, 5.0, 50, and 100 mg/L. The toxicity of fenvalerate was significantly decreased in the presence of 50 and 100 mg/L of commercially available HA and 100 mg/L of aquatic HA. Aquatic FA had no significant influence on the toxicity of fenvalerate. For permethrin, toxicity was significantly decreased at 50 and 100 mg/L of commercially available HA and at all examined concentrations of aquatic HA and FA. However, the magnitude of toxicity amelioration by aquatic HA and FA was not as great as it was with commercially available HA. These results indicate that interactions between HA or FA and pyrethroid insecticides can alter the toxicity of pyrethroid insecticides. Furthermore, the extent of alteration was dependent on the source of dissolved humic material (DHM).
QSARs for predicting reductive transformation rate constants of halogenated aromatic hydrocarbons in anoxic sediment systems
Authors: Peijnenburg Willie J. G. M. , Hart Maarten J. 't , Den Hollander Henri A. , van de Meent Dik , Verboom Hans H. , Lee Wolfe N.
Published: March 2010

Quantitative structure-activity relationships (QSARs) are developed relating initial and final pseudo-first-order disappearance rate constants of 45 halogenated aromatic hydrocarbons in anoxic sediments to four readily available molecular descriptors: the carbon-halogen bond strength, the summation of the Hammett sigma constants of the additional substituents, the summation of the inductive constants of these substituents, and the steric factors of the additional substituents. Comparison of the “initial” and “final” QSARs suggests that the same agent is involved as the reductant in both processes. The rate constants for reduction of seven haloaromatics obtained in 10 different sediment samples are correlated with the organic carbon content of the samples. The correlations are enhanced by taking into account the fraction of the compounds sorbed to the solid phase.

Biotransformation
Phenolic content and antibacterial activity of olive oil waste waters
Authors: Pérez J. , Dela Rubia T. , Moreno J. , Martínez J.
Published: March 2010

The antibacterial effects of olive oil wastes from traditional installations (TM), wastes from modern installations (CM), and wastes from an evaporation pool (EP) were assayed with a soil bacterium (Bacillus megaterium ATCC 33085). Irrespective of the origin, fresh wastes showed higher antimicrobial activity than those from evaporation pools. Among several extractants, ethyl acetate and n-propanol were the most effective organic solvents in the recovery of the antimicrobial activity from wastes. No antimicrobial activity was recovered by hexane extraction. Extracts from evaporation pool wastes showed no antibacterial activity. A good correlation between phenolic content and antimicrobial activity was found.
Application of the group contribution method for predicting the toxicity of organic chemicals
Authors: Gao Chao , Govind Rakesh , Tabak Henry H.
Published: March 2010

A group contribution method has been developed that uses the LC50 values (measured for fathead minnow) for 130 diverse organic compounds. The 130 selected compounds were constituted from 16 chemical groups with —log(LC50) values ranging from 0.85 to 6.09. The method was then used to predict the LC50 values for 10 additional compounds, not in the training set, with good agreement between the predicted and measured values.
Rapid characterization of pesticide residues in contaminated soils by passive sampling devices
Authors: Zabik John M. , Aston Linda S. , Seiber James N.
Published: March 2010

Waste sites contain a wide variety of toxic compounds that can vary greatly in concentration and distribution throughout an area This presents logistical problems in providing an accurate characterization of the site Passive sampling devices (PSDs), which consist of polymeric bags containing 2,2,4-trimethylpentane, C18 bonded-phase silica sorbent, or XAD-4 resin, are easily deployed by burying in soil They require no power source, and only a simple extraction or dilution before GC analysis As a result, personnel time and study costs are minimized These PSDs were evaluated in both lab and field studies using pesticide wastes as a model Although the 2,2,4-trimethylpentane PSDs accumulated the pesticides to the highest level, they were subject to solvent loss, making them unacceptable for use in soils C18 and XAD-4 PSDs were similar in their abilities to accumulate the pesticides Of these two, the C18 PSDs were easier and faster to analyze
Environmental effects of saline oil-field discharges on surface waters
Authors: Boelter Ann M. , Lamming Fred N. , Farag Aida M. , Bergman Harold L.
Published: March 2010

Ambient water samples from streams receiving discharges of coproduced brines from the Salt Creek oil field in Wyoming were collected and tested for toxicity from 1988 to 1990. Exposure to waters downstream from the oil field significantly (P < 0.05) reduced survival and reproduction of Ceriodaphnia dubia compared to the upstream control, but fathead minnows (Pimephales promelas) did not appear to be sensitive to the test conditions. Toxicity to Ceriodaphnia dubia increased as stream flow decreased. Toxicity could not be attributed to H2S, trace metals, or nonpolar organic compounds based on toxicity identification evaluation (TIE) methods. Major inorganic ions (Na+, K+, Cl−, HCO−3, and CO23) appeared to account for the observed toxicity.
A 2-d Life cycle test with the rotifer Brachionus calyciflorus
Authors: Snell Terry W. , Moffat Brian D.
Published: March 2010

A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly <10%. The comparative sensitivity of the rotifer life cycle test is not yet fully characterized, but for the five compounds compared in both Ceriodaphnia and Brachionus, the chronic values of four were within a factor of six of one another. At the chronic value concentrations of 11 toxicants tested in rotifers, there was on average a 33% reduction in r as compared to controls.
Physico-chemical factors influencing ethyleneamine sorption to soil
Authors: Davis John W.
Published: March 2010

Batch equilibrium studies were conducted with 1,2-ethanediamine (EDA) and N-(2-aminoethyl)-1,2-ethanediamine (DETA) to examine the physico-chemical factors that influence the sorption of the amines to soil. Sorption isotherms were generated using a variety of surface and subsurface soils. The results from this investigation demonstrated that, despite their miscibility in water, both EDA and DETA sorbed strongly to soil. The rate of sorption for both amines was fairly rapid, and equilibrium was achieved within several hours. Sorption isotherms could be best described by the Freundlich equation, and a series of Freundlich constants, Kd's, were developed for each soil and amine. Sorption of the ethyleneamines correlated closely with the cation exchange capacity (CEC) and organic content of the soil. Soils with increased CEC and organic content exhibited higher affinities for the amines. This dependence of sorption on CEC and organic content was most likely due to the strong electrostatic interaction between the positively charged amine and the negatively charged soil surface. For all soils DETA sorbed more strongly than EDA, although the sorption constants varied over an order of magnitude for both compounds. In order to decrease the variation observed in the Kd values, the sorption constants were normalized to the organic carbon content of the soil and unique Koc values were developed for each amine. The average Koc values for EDA and DETA were 4,766 and 19,111, respectively.
Contaminated marine sediments: Water column and interstitial toxic effects
Authors: Burgess Robert M. , McKinney Richard A. , Schweitzer Kate A. , Phelps Donald K.
Published: March 2010

The toxicity that contaminated sediments may introduce into the water column has not been measured extensively. In order to quantify this potential toxicity, the seawater overlying two uncontaminated and three contaminated marine sediments was evaluated in the laboratory with the sea urchin Arbacia punctulata fertilization test. Concentrations of polychlorinated biphenyls (PCBs) and copper, as representative contaminants, were also measured. To characterize sources of toxicity, samples were chemically manipulated using reversed-phase chromatography, cation exchange, and chelation. Water column toxicity and contaminant concentrations were higher in the suspended exposures than in bedded exposures. Interstitial water toxicity and contaminant concentrations were generally greater than either bedded or suspended exposures. Chemical manipulation indicated that the observed toxicity in water column exposures was probably caused by metallic and/or nonionic organic contaminants. Conversely, manipulation of interstitial waters did not result in significantly reduced toxicity, suggesting that other toxicants such as ammonia and hydrogen sulfide may be active.
Prediction of biodegradation kinetics using a nonlinear group contribution method
Authors: Tabak Henry H. , Govind Rakesh
Published: March 2010

The fate of organic chemicals in the environment depends on their susceptibility to biodegradation. Hence, development of regulations concerning their manufacture and use requires information on the extent and rate of biodegradation. Recent studies have attempted to correlate the kinetics of biodegradation with the molecular structure of the compound. This has led to the development of structure-biodegradation relationships (SBRs) using the group contribution approach. Each defined group present in the chemical structure of the compound is assigned a unique numerical contribution toward the calculation of the biodegradation kinetic constants. In this paper, a nonlinear group contribution method has been developed using neural networks; it is trained using literature data on the first-order biodegradation kinetic rate constant for a number of priority pollutants. The trained neural network is then used to predict the biodegradation kinetic constant for a new list of compounds, and the results have been compared with the experimental values and the predictions obtained from a linear group contribution method. It has been shown that the nonlinear group contribution method using neural networks is able to provide a superior fit to the training set data and test data set and produce a lower prediction error than the previous linear method.
Effects of acidification on metal accumulation by aquatic plants and invertebrates. 1. Constructed wetlands
Authors: Albers Peter H. , Camardese Michael B.
Published: March 2010

Compared were concentrations of Al, Cd, Ca, Cu, Fe, Hg, Pb, Mg, Mn, Ni, P, and Zn in water, plants, and aquatic insects of three acidified (pH ∼ 5.0) and three nonacidified (pH ˜ 6.5) constructed wetlands. Concentrations of Zn in water and bur-reed (Sparganium americanum) were higher in acidified wetlands than in nonacidified wetlands. Floating nonrooted plants contained mean concentrations of Fe, Mg, and Mn that were higher than recommended maximum levels for poultry feed. The mean concentrations of all metals in insects were below recommended maximum levels for poultry feed and below levels that cause toxic effects in wild birds. Smaller than expected increases of metal concentrations in the water of acidified wetlands were probably due to limited mobilization of metals from the sediments and insignificant changes in sedimentation of aqueous metals. Calcium was lower in acidified than in nonacidified wetland water, but the Ca content of insects and bur-reed was not lower. Low concentrations of Ca in aquatic insects from both groups of wetlands indicate that calcium-rich crustaceans and mollusks are probably important to female waterfowl and their young during the spring, when invertebrates make up the majority of the diet. Although toxic effects from metal ingestion seem to be unlikely consequences of wetland acidification, the adverse effect of low pH on the occurrence of crustaceans and mollusks could threaten egg production and development of young.
Interlaboratory comparison and optimization of hepatic microsomal ethoxyresorufin O-deethylase activity in white sucker (Catostomus commersoni) exposed to bleached kraft pulp mill effluent
Authors: Munkittrick K.R. , van den Heuvel M.R. , Metner D.A. , Lockhart W.L. , Stegeman J.J.
Published: March 2010

Twelve samples of minced liver from white sucker (Catostomus commersoni) were delivered to 14 laboratories in Canada and the United States for the analysis of hepatic ethoxyresorufin O-deethylase (EROD). Samples were collected from a site exposed to bleached kraft pulp mill effluent (BKME) and from a reference site. All laboratories analyzing EROD activity successfully differentiated between effluent exposed fish (high activity) and reference samples (low activity). Absolute activity detected in samples from the induced site varied greatly with analysis method; assay conditions at most laboratories were suboptimal for white sucker microsomes, and absolute activity of the samples was most affected by pH, temperature, and substrate limitation. The method used to quantify protein was also thought to contribute greatly to the observed variability. However, the induction level (mean exposed divided by mean reference values) was similar. Relative induction did not appear to be affected by storage time, pH, buffer, assay time, or assay temperature. The induction level was not affected by whether postmitochondrial supernatant (PMS; 10,000 g) or microsomal fractions (100,000 g) were used in analysis, although absolute activity was 3.5 times higher with microsomal preparations. There was a statistically significant agreement in the rankings of high-activity samples using microsomal preparations; a corresponding ranking of PMS values was nonsignificant. The presence of cytochrome P4501A enzyme was detected using monoclonal antibody 1-12-3 against scup P4501A1. Immunoblotting showed 8.4-fold differences in the measured levels of the single cross-reacting band, confirming the distinction between exposed and reference fish determined by EROD assay.
The fragile relationship of business and environmental science
Authors: Carpenter George D.
Published: March 2010

The evolution of environmental science has resulted in its politicization. This politicization of science threatens the value of science as a means of answering society's questions and concerns. Therefore, it also threatens the traditionally strong relationship between environmental science and business. To forestall or reverse this threat, the scientific community needs to hold itself accountable for the use of science in the public sphere of social policy and to accept responsibility for explaining its work in terms the public can understand.
Re-exposure of mallards to selenium after chronic exposure
Authors: Heinz Gary H.
Published: March 2010

Adult male mallards (Anas platyrhynchos) were fed a control diet or a diet containing 15 ppm selenium as seleno-D,L-methionine for 21 weeks. After this initial exposure, the mallards were fed untreated food for 12 weeks, then were re-exposed to selenium at 100 ppm for five weeks. During re-exposure to 100 ppm selenium, the birds that had previously been exposed to 15 ppm selenium and those that had not previously been exposed did not differ in percentage of mortality (14.7 and 14.3%), weight loss in survivors (39.3 and 41.2%), selenium concentrations in the livers of survivors (35 and 53 ppm, wet weight), or selenium concentrations in the livers of birds that died (35 and 40 ppm, respectively). When the data from the birds that had previously been exposed to 15 ppm selenium were combined with the data from the birds that had not previously been exposed, selenium concentrations in the livers of birds that had died on the 100-ppm selenium treatment (38 ppm) did not differ from the concentrations in the livers of birds that had survived (43 ppm).
Compatibility of functional groups in Kow-based QSARs: Application to nitro compounds
Authors: Banerjee Sujit , Williams Chris L.
Published: March 2010

Nitro compounds are particularly difficult to handle in simple Kow-based QSARs, owing to differences in their lipid-phase activity coefficients. These differences can be corrected, in part, through inclusion of a term in octanol solubility. A procedure for identifying potentially incompatible groups in a given QSAR is suggested. The quality of a QSAR is best if the interactions of the functional groups involved with octanol fall within a narrow range. These interactions are easily calculated by the UNIFAC method.
Comparison of effluent toxicity results using Ceriodaphnia dubia cultured on several diets
Authors: Norberg-King Teresa J. , Schmidt Shaneen
Published: March 2010

Several diets have been proposed for Ceriodaphnia dubia, but no single diet has been universally accepted as optimal for toxicity testing. Although several diets for Ceriodaphnia dubia cul-turing and testing are commonly used, little or no data exist on whether toxicity varies with the diet. This study evaluated several combinations of yeast-Cerophyl-trout chow (YCT), Selenastrum capricornutum, and Selenastrum capricornutum-Cerophyl foods for routine culture performance and the sensitivity of the offspring in subsequent acute toxicity tests with effluents. Variations in the diets included use of a vitamin-fortified yeast added to the YCT, algae (Selenastrum capricornutum) grown in two different algal media, and different feeding rates of the algae-Cerophyl diets. Eleven diets were evaluated in a multigeneration feeding study, but only seven were used in subsequent toxicity tests. The young produced from each of the seven diets were tested in 48-h acute tests with three different effluents across the generations. Toxicity tests with the effluents gave LC50s that were within a factor of two of one another, regardless of the food used for culturing. These results indicate that several diets are satisfactory for culturing Ceriodaphnia dubia and that the results of the toxicity tests are comparable.