bluuebunny/crossref_metadata_2025 huggingface dataset:
Trend analysis and mass-discharge estimation of atrazine in southwestern Ontario Great Lakes tributaries: 1981–1989
Authors: Bodo Byron A.
Published: March 2010

Aqueous concentration time series of the herbicide atrazine and its phytotoxic metabolite desethylatrazine obtained from 1981 to September 1990 in the Thames, Grand, and Saugeen rivers draining agricultural southwestern Ontario were analyzed to ascertain temporal trend, seasonal variation, and mass-discharge patterns Substantial year-to-year changes were evident. Data suggest that the greatest applications of the decade might have occurred in 1984; however, in 1985 significant decreases in levels were observed at all three sites, apparently due to an abrupt shift away from corn cultivation. Mass-discharge estimates generally parallel the concentration trends but also reflect hydrometeorologic trends. In 1984 for the Thames basin, extremely high concentrations together with high flows combined to export about 13 tonnes (t) atrazine plus metabolite, the largest single annual loss to surface-water systems observed over the decade. Driven by the annual spring-summer application cycle, aqueous concentrations surge in late May to reach annual peaks in late June and early July Despite the declining levels of recent years, Thames River data suggest that the probability of exceeding the Canadian water quality guideline of 2 μg/L for protection of aquatic life, primarily algae and vascular plants, may yet approach 65%. The greatest risks to susceptible species are likely associated with large summer storm runoff in areas of high soil to surface water transfer potential. Herbicide usage in general continues in large quantities, and continued surveillance appears warranted. Further research is required to ascertain the ultimate fate of these compounds in end receiving waters such as the Great Lakes
Genotoxic effects of complex marine sediment extracts on V79 chinese hamster lung fibroblasts
Authors: Mueller Cornelia , Anderson Stephanie , Pesch Gerald
Published: March 2010

A mammalian in vitro system was used to evaluate the genotoxic potential of two complex environmental samples. Sister chromatid exchanges (SCEs) were measured in Chinese hamster V79 lung fibroblast cells, following exposure to whole extracts of sediments collected from a highly contaminated harbor — Black Rock Harbor, Connecticut (BRH) — and from a reference site — central Long Island Sound (CLIS). Characterization of BRH sediment by analysis of prepared chemical extracts revealed high concentrations of polyaromatic hydrocarbons, anthraquinones, carbazoles, and several inorganic substances that are genotoxic and capable of inducing SCEs. The CLIS sediment, although cleaner than BRH sediment, does contain low levels of similar contaminants. For instance, BRH sediment contains 3.16 μg/g of the polynuclear aromatic hydrocarbon benzo[a]pyrene (BP), whereas CLIS sediment contains only 0.807 μg/g BP. Sediments were extracted with organic solvents and redissolved in dimethyl sulfoxide (DMSO) for culture exposure. Following exposure, extract-treated cells were evaluated for increased frequencies of SCEs. All assays were performed with and without exogenous S9 activation. Positive responses were observed only in the presence of exogenous S9 metabolism. Results indicated a concentration-dependent increase in SCEs in cells exposed to whole BRH sediment extracts and a smaller but significant increase in SCEs in cells exposed to whole CLIS sediment extracts. Four times as much CLIS material (0.13 g extracted sediment [dry wt.]/ml of exposure media) was needed to induce a significant doubling in SCEs, compared to BRH material, in which only 0.03 g extracted sediment (dry wt.)/ml of exposure media was needed. These findings imply that this short-term in vitro bioassay can be used to evaluate the genotoxic potential of complex environmental samples such as contaminated marine sediments.
Modulation of mixed-function oxidase activity in black-headed gulls living in anthropic environments: Biochemical acclimatization or adaptation?
Authors: Fossi M. Cristina , Leonzio Claudio , Focardi Silvano , Lari Lorena , Renzoni Aristeo
Published: March 2010

This study was conducted to explore the role of the mixed-function oxidase (MFO) detoxication system in the “biochemical acclimatization” or adaptation of gulls to anthropic environments. In three different populations of black-headed gull (Larus ridibundus) feeding in a lagoon, in municipal and industrial landfills, MFO microsomal hepatic activities (aldrin epoxidase, 7-ethoxyresorufin-O-deethylase, NADPH-cytochrome c reductase, NADH-cytochrome c reductase, and NADH-ferricyanide reductase), microsomal α-naphthylacetate esterase activity, cytochrome P-450 forms, and chlorinated hydrocarbon residues were determined. Induction tests and in vitro comparative kinetics studies were completed between the different populations of gulls. The detoxicant activities of the MFO system were much higher in the landfill gulls, especially those of the industrial landfill, than in lagoon gulls. Lineweaver-Burk plots for aldrin epoxidase show an apparent Km four to five times lower in the gulls of the industrial landfill than in the other two populations. The origin of the potentiated detoxication activities in landfill gulls is investigated and the hypotheses of biochemical acclimatization and genetic adaptation are discussed.
Dietary uptake and biomagnification of four chlorinated hydrocarbons by guppies
Authors: Clark Kathryn E. , Mackay Donald
Published: March 2010

Laboratory experiments are described in which guppies (Poecilia reticulata) were fed food containing hexachlorobenzene, mirex, 2,2′,3,3′,4,4′,5,6′-octachlorobiphenyl, and octachlorodibenzofuran. The chemical concentrations in the food and the feeding rate were varied to determine the effect of these variables on the assimilation efficiency. Increasing the dietary intake by increasing the concentration (or fugacity) of a chemical in the food causes a proportional increase in the steady-state concentration or fugacity of the chemical in the fish; i.e., the assimilation efficiency is constant. Increasing the dietary intake by increasing the feeding rate produces a less than proportional increase in the steady-state concentration or fugacity of the chemical in the fish. This apparent drop in assimilation efficiency is the result of an increased rate of loss by egestion. Mirex and octachlorobiphenyl were observed to biomagnify; i.e., the steady-state fugacities achieved in the fish exceeded the fugacities in the food. These findings are in accord with the assertions of a fugacity model of bioaccumulation.
Acute toxicities of permethrin, fenitrothion, carbaryl and carbofuran to mosquito larvae during single- or multiple-pulse exposures
Authors: Parsons J. T. , Surgeoner G. A.
Published: March 2010

The acute toxicity to third-instar Aedes aegypti (L.) of two 1-h exposures to each of five insecticides (technical permethrin, microencapsulated permethrin, fenitrothion, carbaryl, and carbofuran) was determined with static toxicity tests. The toxicity of two 1-h exposures to these test compounds, separated by a 6-h insecticide-free period, was compared to that of continuous 2-h exposures. Acute toxicity was expressed as LC50 values based on survival to the adult stage. The LC50 for two 1-h exposures to microencapsulated permethrin (180 μg/L) was significantly lower than that for a continuous 2-h exposure (250 μg/L). There was no significant difference between LC50 values for two 1-h and continuous 2-h exposures for each of technical permethrin (2.03–2.32 μg/L), fenitrothion (49.4–48.8 μg/L), carbaryl (3,040–3,470 μg/L, and carbofuran (1,590–2,130 μg/L).

Increasing time between two 1-h exposures to carbaryl from 6 to 24 h did not significantly affect acute toxicity (LC50 values were 3.0 mg/L and 3.8 mg/L, respectively). The LC50 for four 1-h exposures to carbaryl each separated by a 12-h period in clean water (LC50 = 1.7 mg/L) was not significantly different from that of a continuous 4-h exposure (LC50 = 1.4 mg/L). These results suggest that there was no recovery from the effect of insecticide poisoning during the insecticide-free period between exposures.
Degradation of toluene and p-xylene in anaerobic microcosms: Evidence for sulfate as a terminal electron acceptor
Authors: Haag Franziska , Reinhard Martin , Mccarty Perry L.
Published: March 2010

The degradation of aromatic hydrocarbons (benzene, toluene, ethylbenzene, p-xylene, o-xylene, 1,3,5-trimethylbenzene, and naphthalene) under anaerobic conditions was studied in column microcosms developed with aquifer material from the vicinity of a gasoline spill at Seal Beach, California. In one column, which did not receive any electron acceptors other than those naturally present (sulfate and carbon dioxide), more than 60% of the toluene was oxidized to CO2. The other six added substrates were not degraded when the toluene supply was constant. In another column, the addition of toluene was discontinued after 126 d, which coincided with the onset of p-xylene degradation. Addition of sulfate, the only electron acceptor that was detected, stimulated the transformation of toluene in batch experiments.
Evaluation of gas chromatography with electrolytic conductivity detection and electron capture detection and use of negative chemical ionization GC-MS for the analysis of PCBs in effluents
Authors: Greaves John , Harvey Ellen , Huggett Robert J.
Published: March 2010

Gas chromatography with electrolytic conductivity detection and electron capture detection in combination with gas chromatography-mass spectrometry, operated in the electron capture negative chemical ionization mode, were evaluated as techniques for the analysis of polychlorinated biphenyls in wastewater from an industrial facility. The specificity of the electrolytic conductivity detector reduced sample turnaround time because extracts could be analyzed without fractionation or cleanup Using a 2 L sample, this methodology had a quantification limit, based on Aroclor 1260, of 0.1 μg/L and a detection limit of approximately 0.03 μg/L The electron capture detector was subject to interferences from nonhalogenated compounds and required additional sample cleanup Electron capture negative chemical ionization gas chromatography-mass spectrometry was highly specific and provided full mass spectra of polychlorinated biphenyl congeners at the same quantification limit. Effluents from the facility had polychlorinated biphenyl concentrations of 0.1 to 1 μg/L.
Desorption of tetrachloroethene and 1,2-dibromo-3-chloropropane from aquifer sediments
Authors: Pignatello Joseph J.
Published: March 2010

Desorption of tetrachloroethene (TeCE) or 1,2-dibromo-3-chloropropane (DBCP) from aquifer sediment (0.19% organic carbon) was monitored following sorption for 6 or 30 d in 100 μM aqueous solutions. The compounds were desorbed by a previously developed purge technique in which a third phase of Tenax GC® polymeric adsorbent beads provided a sink for desorbed chemical, thereby simulating desorption to infinite dilution. Sorbed concentrations in the sediments were quantified by hot acetone extraction of sacrificed replicates. More than 95% of the initial sorbed compound was desorbed within the first 4 d, but a persistent fraction (8–15 μg/kg, 0.4 to 1%) remained associated with the sediments for at least 35 d. The desorption curves were little affected by the prepurge sorption time. The results may rationalize the unexpectedly high sediment-associated concentrations of a similar compound (1,2-dibromoethane) in a long-contaminated aquifer.
Evaluation of selected lipid methods for normalizing pollutant bioaccumulation
Authors: Randall Robert C. , Lee Henry , Ozretich Robert J. , Lake James L. , Pruell Richard J.
Published: March 2010

Current environmental models use organism lipid concentrations to estimate maximum pollutant bioaccumulation potentials. This collaborative study has shown that significantly different lipid concentrations (3.5X) are found when using common, but different, extraction solvents and methods. Based on these variable lipid values, models that estimate tissue pollutant concentrations normalized to lipid will give significantly different bioaccumulation estimates. To reduce that variability, a standard lipid method needs to be developed or adopted.
An evaluation of a naidid oligochaete as a toxicity test organism
Authors: Smith David P. , Kennedy James H. , Dickson Kenneth L.
Published: March 2010

Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and body contact with sediments and interstitial water. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of 1 year or more to encompass several generations. Most naidid oligochaetes have generation times of 3 to 7 d. The cosmopolitan-distributed naidid Pristina leidyi Smith 1896 has potential for sediment toxicity testing. Cultures of Pristina leidyi were maintained in the laboratory for over 2 years. A rabbit chow suspension provided both substrate and food source. A reproducing viable culture with little variation in growth was maintained at 24 ± 4°C and a 16:8-h light:dark photoperiod. Population growth in a characterized reference sediment peaked at 24 d with an increase in variation. It is recommended that test lengths should not exceed 18 d. The 48-h LC50s for cadmium and vanadium using Pristina leidyi were 215 μg/L and 30,830 μg/L, respectively, at a water hardness of 95 mg/L as CaCO3.
The hazard assessment of pulp and paper effluents in the aquatic environment: A review
Authors: Owens James William
Published: March 2010

The hazard assessment of pulp and paper effluents in the aquatic environment is a complex task. Hundreds of individual compounds in pulping effluents and site-specific differences in processes, effluent treatment, and receiving ecosystems hinder hazard assessment. As a result, it is difficult to relate environmental effects with specific contaminants. Conventional parameters such as organic and nutrient loadings, solids deposition, and color complicate efforts to define chemical toxicants by causing environmental impacts at community and population levels. Reproduction is the most sensitive, consistent, and relevant end point tested to date in the laboratory, in mesocosms and experimental streams, and in field situations near some pulping discharges. Despite the application of a wide range of within-organism measurements, only the induction of mixed-function oxidase activities has been associated with exposure to particular effluent compounds in field situations. No complete mechanism of toxic action has been demonstrated that connects contaminant exposure, within-organism responses, whole-organism effects, and effects at the population and the community levels. Hazard assessments of pulping effluents require multidisciplinary efforts that integrate chemical, toxicological, and biological data at several organizational levels. Tiered or stepwise assessments are recommended that first clarify what adverse effects have occurred and then attempt to identify the responsible contaminants.
Effects of esfenvalerate on aquatic organisms in littoral enclosures
Authors: Lozano Stephen J. , O'Halloran Susan L. , Sargent Kenneth W. , Brazner John C.
Published: March 2010

The effects of esfenvalerate [(S)-α-cyano-3-phenoxybenzyl(S)-2-(4-chlorophenyl)-3-methylbutyrate] on plant and animal communities were observed in 12 littoral enclosures (5 × 10 m) in a 2-ha pond near Duluth, Minnesota, at six concentrations (0, 0.01, 0.08, 0.2, 1, and 5 μg/L, nominal) for eight weeks. Esfenvalerate exposures of 1 and 5 μg/L resulted in drastic reductions or elimination of most crustaceans, chironomids, juvenile bluegills (Lepomis macrochirus), and larval cyprinids. Abundance of some copepod and insect genera declined at esfenvalerate concentrations of 0.08 to 0.2 μg/L, and these effects were apparent up to 53 d. Some invertebrate communities were able to recover by day 25 in enclosures containing concentrations of ≤0.2 μg/L esfenvalerate.
Use of outdoor artificial streams to determine threshold toxicity concentrations for a petrochemical effluent
Authors: Crossland N.O. , Mitchell G.C. , Dorn P.B.
Published: March 2010

A system of six partly flow-through, partly recirculating, streams was constructed outdoors from stainless steel and divided into pool and riffle sections to closely simulate a natural stream environment. The organic fraction extracted from the effluent of a petrochemical manufacturing plant was identified as a mixture of chlorinated ethers. The effluent extract was applied to three of the streams to maintain nominal concentrations of chlorinated ethers of 0.5, 1.0, or 2.0 mg/L for a period of 28 d. A fourth stream was treated with 0.25 mg/L for 21 d; this was then increased to 4.0 mg/L for a further 7 d. Two streams were untreated and served as controls. There were no detectable effects of the treatments on macroinvertebrate population densities. There was a marked effect on the drift of macroinvertebrates at a concentration of 2.0 mg/L, but there was no effect at lower concentrations. There was an effect on the feeding rates of Gammarus pulex at concentrations of 1.0, 2.0, and 4.0 mg/L, but there were no effects at concentrations of 0.25 and 0.5 mg/L. The results of this experiment were compared with those obtained in 7-d, single-species toxicity tests. On the basis of the toxicity tests, the no-observed-effect concentration (NOEC) for the most sensitive biological response—growth of Daphnia magna — was 1.0 mg/L. On the basis of the field test, the NOEC for the most sensitive biological response — feeding rate of G. pulex — was 0.5 mg/L.
Rapid establishment of test conditions and trophic-level interactions in 0.04-hectare earthen pond mesocosms
Authors: Howick Gregory L. , Giddings Jeffrey M. , Denoyelles Frank , Ferrington Leonard C. , Kettle W. Dean , Baker Debra
Published: March 2010

A mesocosm study of pesticide effects was conducted between November 1987 and November 1988 using 0 04-ha earthen ponds The bottoms of the ponds were covered with sediments from an old farm pond, filled with aged reservoir water, and stocked with fifty 11- to 17-cm blue-gill sunfish Importing mature communities rapidly produced taxonomically rich ecosystems Coefficients of variance among ponds for taxonomic richness and population densities were modest (typically 10–30%) and usually inversely related to abundance Unchecked bluegill reproduction resulted in expected effects on lower trophic levels Crustacean zooplankton were nearly eliminated, which led to poor growth of the juvenile bluegill Phytoplankton densities appeared to increase as grazing pressure from zooplankton was reduced Insect emergence was not obviously impacted by fish predation Potential indirect effects on fish, such as growth impairment caused by pesticide induced reduction of food supply, could be obscured if zooplankton were nearly eliminated by over-predation This suggests a need to control bluegill reproduction to achieve a more balanced ecosystem
Occurrence and fate of tributyl- and triphenyltin compounds in western mediterranean coastal enclosures
Authors: Tolosa I. , Bayona J. M. , Albaigés J. , Merlini L. , De Bertrand N.
Published: March 2010

Tributyltin (TBT) and its degradation products, mono- (MBT) and dibutyltin (DBT) have been determined in the dissolved and particulate phases of seawater, sediments, and biota collected in some representative open and enclosed coastal areas of the western Mediterranean Sea. The highest levels were found in sediments and seawater of dry docks and marinas, closely related with boating activity and clearly decreasing according to the distance from the point sources. Triphenyl- (TPhT) and diphenyltin (DPhT) were also identified for the first time in seawater and sediments collected in marinas, exhibiting concentrations similar to TBT. Concentration ratios between TBT/DBT and TPhT/DPhT in each environmental compartment as well as the field partition coefficients (Kd, K′d, and Kb) of the different tin species point out the complexity of organotin speciation, because accumulation and degradation processes occur at different rates, depending on the environmental compartment.
Investigations of a neurotoxic oscillatorialean strain (Cyanophyceae) and its toxin. Isolation and characterization of homoanatoxin-a
Authors: Skulberg Olav M. , Skulberg Randi , Carmichael Wayne W. , Andersen Rolf A. , Matsunaga Shigeki , Moore Richard E.
Published: March 2010

A neurotoxic cyanophyte (Oscillatoriales) was characterized biologically and chemically with respect to toxic properties. The organism, identified as Oscillatoria formosa (Phormidium formosum [Bory ex Gom.] comb.n. Anagnostidis et Komárek), was isolated and brought to pure culture. The dried biomass used in these investigations was grown from the strain NIVA-CYA 92 in semicontinuous culture, giving yields of about 400 mg/d dry weight of the organism, and the toxic component was extracted and separated on C18 Bond Elut® cartridges followed by HPLC purification. The purified toxin was used for structure determination by low-resolution MS and nuclear magnetic resonance. The toxin is a secondary amine alkaloid identified as methylene-anatoxin-a and was therefore named homoanatoxin-a. It is a potent neuromuscular blocking agent (LD50 [i.p., mouse] 250 μg/kg). Toxicosis in the lethal dose range leads to severe body paralysis, convulsions, and death by respiratory arrest in 7 to 12 min. Experiments with rat phrenic nerve-hemidiaphragm preparations demonstrated that the physiological effects of homoanatoxin-a are related to those observed for d-tubocurarine.
Copper accumulation on gills of fathead minnows: Influence of water hardness, complexation and pH of the gill micro-environment
Authors: Playle Richard C. , Gensemer Robert W. , Dixon D. George
Published: March 2010

Water pH in the gill micro-environment of adult fathead minnows (Pimephales promelas Rafinesque) was measured by means of opercular catheters and latex masks. Synthetic soft water of pH <5.7 was rendered more basic as it passed over the gills and water of pH >5.7 was made more acidic, so that pH of the gill micro-environment stayed at approximately 5.4 to 5.9 over the inspired pH range 4.8 to 6.3. Copper would therefore be >99% Cu2+ at the gills. To measure Cu accumulation on gills, the target organ for Cu toxicity, adult fathead minnows were exposed for 2 to 3 h to 16 μg/L Cu in synthetic soft water (Ca2+ and Na+ approximately 50 μeq/L) at pH 4.8 and 6.3. Gill Cu concentrations were about 1.7 μg Cu/g wet tissue for the inspired pH 4.8 and 6.3 exposures. Added Ca2+ of 2,100 or 4,000 μeq/L reduced gill Cu accumulation during exposures at pH 4.8 but not at pH 6.3. EDTA eliminated Cu deposition at both pH 4.8 and pH 6.3 when equimolar with Cu, but reduced Cu deposition (by 50%) when half equimolar only in the pH 4.8 exposures. These results can be explained by Ca2+ and H+ competition with Cu for gill binding sites and by complexation of Cu by EDTA. Added CaCO3 did not reduce gill Cu, although both competition by Ca2+ and complexation by CO2−3 were expected. Water chemistry calculations suggested that because little CO2−3 is available at pH < 7, CO2−3 from CaCO3 is less likely to affect Cu deposition on fish gills than is Ca2+ from CaCO3.
Comparison of Przm and Gleams computer model predictions with field data for alachlor, metribuzin and norflurazon leaching
Authors: Mueller Thomas C. , Bush Parshall B. , Banks Philip A. , Jones Ronald E.
Published: March 2010

The ability of the pesticide root zone model (PRZM) and groundwater loading effects of agricultural management systems (GLEAMS) model to simulate movement of three herbicides was evaluated with site-specific soil, environmental, and pesticide data. Field studies examined norflurazon movement in a Dothan loamy sand in which cotton (Gossypium hirsutum L.) was grown, and alachlor and metribuzin movement in an Appling sandy loam. Actual herbicide concentrations were always greatest near the soil surface. The PRZM and GLEAMS computer simulation models accurately predicted the total herbicide present in each profile less than 20 d after application. The models overestimated herbicide movement into the soil profile in later simulations. The model predictions generally agreed with the relative location of alachlor and metribuzin in simulations less than 7 d after herbicide applications, but simulations beyond 7 d after herbicide application deviated from actual concentrations. PRZM accurately predicted that most of the applied norflurazon would remain close to the soil surface 84 d after herbicide application, whereas GLEAMS inaccurately predicted that norflurazon would be located throughout the soil profile, although the predicted depth to the limit of detection by both models was accurate.
Partial rapid metabolism of 1,2-dichloroethane by Methylosinus trichosporium OB-3b
Authors: Riebeth D. M. , Belser N. O. , Castro C. E.
Published: March 2010

Resting cell suspensions of the soil methylotroph Methylosinus trichosporium OB-3b rapidly dehalogenate ethylene dichloride, but the process stops after one halogen is removed. Work with 14C- and 13C-labeled 1,2-dichloroethane shows that the biodehalogenation entails a direct hydrox-ylation of one of the CCl bonds to produce chloroethanol. The latter is rapidly oxidized to chloroacetic acid. The organism does not metabolize this acid on the time scale of these experiments.
Comparison of growth and mortality in juvenile sand dollars (Dendraster excentricus) as indicators of contaminated marine sediments
Authors: Casillas Ed , Weber Doug , Haley Craig , Sol Sean
Published: March 2010

A bioassay system involving exposure of juvenile sand dollars (Dendraster excentricus) to contaminated sediments from Puget Sound, Washington, was evaluated. In these bioassays, juvenile sand dollars were exposed to serially diluted sediments from three urban areas with different types and levels of contamination. Physical and biochemical measures of growth (i.e., length or diameter, DNA content, and protein content) were then evaluated for sensitivity and concentration responsiveness to a chemical gradient and compared with mortality as biological indicators of toxicant effects in sediments. Growth measurements appeared to be more sensitive indicators of contaminant exposure than mortality. Sediment mixtures with the highest proportions of contaminants were generally lethal to these organisms, but at lower sediment concentrations, where significant mortality did not occur, significant reductions in growth were observed. The results suggest that measurement of growth, either morphometrically or biochemically, in conjunction with mortality can provide better discrimination for assessing toxicity in sediment bioassay systems. Also, because impaired growth is a sublethal effect of contaminant exposure, it may be a useful indicator for assessing the long-term (chronic) effects of exposure to contaminants on marine organisms.
Influence of surface films on the fate of deltamethrin following aerial application to prairie ponds
Authors: Muir Derek C. G. , Yarechewski Alvin L. , Neal B. Richard
Published: March 2010

The dissipation of the insecticide deltamethrin was studied in natural prairie ponds (0 3–1 3 ha, 1–1 5 m depth) following aerial application Four ponds were treated at normal field rates (7 5 g/ha) with deltamethrin, two in June 1986 and two others in June 198− Parts per billion concentrations of deltamethrin were observed in the surface microlaver (0 12 mm, sampled with a glass plate) in all treatments during the first 8 to 12 h after application Levels of deltamethrin were about 1000-fold lower in subsurface water (10–20 cm depth) Pseudo first order half-lives of deltamethrin in the surface film varied from 0 6 to 5 h and were influenced by macrophvte density and amount of sprav deposit Half-lives of deltamethrin in subsurface waters were less variable, averaging 14 h Deltamethrin was not detected in sediments (0–2 5 cm depth containers, detection limit 10 ng/g dry weight) following sprav application in either year The stereoisomer (α R, 1R/α S 1S-cis-) was detected in subsurface water along with a cyclopropvl acid derivative (DBCA) and phenoxybenzoic acid (PBA) Concentrations of DBCA and PBA 10 to 100 fold higher than that of the parent compound persisted in subsurface water for 18 to 25 d after spray deposition The surface film influenced the overall fate of deltamethrin by reducing diffusive transport to subsurface waters and increasing the amount of the insecticide available for volatilization and degradation
Time effects on enzyme activity in the mosquitofish, Gambusia Holbrooki
Authors: Heagler M. G. , Mulvey M.
Published: March 2010

A study to examine the maximum interval between time of death and enzymatic sampling was conducted to determine the appropriate interval to procure reliable data from electrophoretic analysis of mosquitofish, Gambusia holbrooki. Dead fish were sampled at regular time intervals (0, 8, 12, 24 hours) and electrophoresed. All 26 of the enzyme systems assayed were reliably scorable 8 hours after death, with a large number remaining scorable up to 24 hours after death.
A simple method of pH control for static and static-renewal aquatic toxicity tests
Authors: Mount David R. , Mountz Donald I.
Published: March 2010

In response to the need for pH control in aquatic toxicity tests we developed methods to control pH by manipulating the carbon dioxide concentration in the atmosphere over test solutions We believe the use of CO, is preferable to other types of pH control advantages include less alteration of normal test solution chemistry and use of a natural buffer system to achieve ongoing pH control Physical requirements for the use of this method and currently known limits of its use are described Several methodological variations are discussed, along with example applications of the technique
Fate and biological effects of contaminated vegetation in a tennessee stream
Authors: Stewart A. J. , Haynes G. J. , Martinez M. I.
Published: March 2010

Potamogeton foliosus (an aquatic plant) and filamentous algae from a settling basin with contaminated sediment became enriched with polychlorinated biphenyls (PCBs), Co, Cd, Cu, Hg, Ni, Mn, U, and Zn During the growing season, large amounts of the contaminated Potamogeton foliosus and algae were exported downstream from this basin to East Fork Poplar Creek (EFPC) We used drift nets to estimate the loading rates of the plants to EFPC, analyzed samples of the plants for metals, and conducted a series of experiments with snails (Elimia clavaeformis), amphipods (Gammarus sp), and a microcrustacean (Ceriodaphnia dubia) to evaluate the possible effects of inputs of the vegetation to EFPC biota Little of the vegetation that entered the stream was transported intact as far as 1 4 km During the growing season, inputs of organic carbon to this 1 4-km segment of stream due to the deposition of the plants were at least 2 4 times greater than autochthonous production Thus the vegetation was bioenergetically important to at least a 1 to 3-km reach of EFPC The experiments showed that all three types of animals could distinguish between contaminated (CON) and noncontaminated (NC) Potamogeton foliosus Snails preferred the NC plants over the CON plants, these animals also had lower growth rates on CON plants than on NC plants Amphipods preferred CON plants over NC plants in a 48-h experiment, but preferred NC plants over CON plants in a 7 d experiment Leachates prepared from CON Potamogeton foliosus were toxic to Ceriodaphnia, those prepared from NC Potamogeton foliosus were not Energy-subsidy and/or contaminated food aspects of the Potamogeton inputs could help explain why pollution sensitive invertebrates such as mayflies and stoneflies are not present in EFPC immediately downstream from the settling basin
Genetic indicators of environmental stress in central mudminnow (Umbra Limi) populations exposed to acid deposition in the Adirondack Mountains
Authors: Kopp Richard L. , Guttman Sheldon I. , Wissing Thomas E.
Published: March 2010

Horizontal starch gel electrophoresis was used to characterize the genetic structure of central mudminnow (Umbra limi) populations from acid stressed (low pH/high Al) and nonacid-stressed sites in the north branch of the Moose River (NBMR), New York, in order to determine if environmental shifts were accompanied by detectable shifts in genetic structure Central mudminnow populations in the NBMR were characterized by significantly (p ≥ 0 05) lower heterozygosity levels at stressed sites (H (mean number of heterozygotes per locus per individual) = 0 060 0 102) than reference sites (H = 0 130, 0 142) Additionally, several genetic loci demonstrated either consistent (isocitrate dehydrogenase, phosphogluconate dehydrogenase) or moderately consistent (glucose 6 phosphate isomerase 1 malate dehydrogenase-1, mannose-6 phosphate isomerase) genotypic shifts in comparisons between populations at reference and low pH/high Al sites Populations at acid stressed sites were characterized by higher frequencies of one particular allozyme, suggesting that environmental conditions were acting as a selective force In acute laboratory toxicity tests (pH, 4 5, Al, 7 5 mg/L), the most tolerant fish were significantly more genetically variable, indicating that genetic diversity may be beneficial to the survival of individual fish experiencing physiological stress
Effects of aqueous and dietary exposure of dieldrin on survival, growth and bioconcentration in mallard ducklings
Authors: Nebeker Alan V. , Griffis William L. , Stutzman Thomas W. , Schuytema Gerald S. , Carey Lori A. , Scherer Susan M.
Published: March 2010

Tests were conducted to determine the effects of dieldrin in continuous flow water and in food on survival, growth, and bioconcentration in mallard ducklings (Anas platyrhynchos) Di eldrin had no effect on survival or growth at concentrations at or below water saturation (0 2 mg/L), but tissue (lipid, skin, liver, muscle, brain, blood) dieldrin concentrations increased rapidly (up to a mean of 217 μg/g) and bioconcentration factors (BCFs) showed up to 1,995 times (mean steady state lipid BCF of 1,345) more dieldrin in tissues than in the water Significant effects on survival, growth, and behavior were observed in ducks fed dieldrin spiked food, and tissues rapidly concentrated dieldrin up to five times more than those in the water-only test (mean of 1,000 μg/g), although the BCFs were much lower (water BCFs were up to 18 times higher) The dietary 96 h LC50 value (50% death at 96 h) was 165 μg/g dieldrin, the 24-d dietary LC50 was 29 5 μg/g The lowest 24 d LOAEL (lowest observed adverse effect level) and NOAEL (no observed adverse effect level) values were 16 4 and 0 3 μg/g, respectively, based on growth (total weight) A screening level wildlife criteria (SLWC) value of 0 0001 mg/L was derived by using data from this study Steady-state tissue dieldrin concentrations at which growth impairment occurred were near 140 (lipid), 80 (skin), 20 (liver), 10 (brain), and 5 (muscle) μg/g dieldrin Tissue dieldrin concentrations where no growth impairment was observed were near 3 0 (lipid), 1 0 (skin), and <1 0 (liver, brain, and muscle) μg/g
Matrix decision procedure to assess new pesticides based on relative groundwater leaching potential and chronic toxicity
Authors: Britt Janice K. , Mcdowell Ted C. , Dwinell Steven E.
Published: March 2010

The high usage of pesticides in the subtropical climate of Florida presents a worst case scenario under which registrations that may impact public health and the environment must be judged A methodology is presented that utilizes chemical environmental fate factors in conjunction with chronic toxicity parameters to better assess new active ingredients that are submitted for registration A ranking index related to leaching potential is assigned to a pesticide as a preliminary screening process If the index falls within a certain numerical range, then a more in depth analysis of the environmental fate and toxicological data for the pesticide occurs A decision matrix that incorporates the results of chronic toxicity analysis and computer simulation of leaching behavior is then applied to the pesticide to decide which registration action may be appropriate This tool has widespread potential for assessing the leaching potential of pesticides to, and the chronic toxicity of pesticides in, ground water
Pesticides in ground water, surface water and spring runoff in a small saskatchewan watershed
Authors: Waite D.T. , Sommerstad H. , Grover R. , Kerr L. , Westcott N.D.
Published: March 2010

The movement of several pesticides was studied from 1985 to 1987 in a small, agricultural watershed The watershed contained a distinct, ephemeral stream bed and two permanent, small reservoirs The five herbicides measured −2,4 dichlorophenoxyacetic acid (2,4 D), dicamba, bromoxynil, diclofop-methyl, and triallate – were those most commonly used in the watershed Of the 105 collected ground water samples 47% contained residues of one or more herbicides Residues in surface water samples were less frequent, and concentrations were lower than those in ground water All spring snowmelt runoff samples were collected in 1985 and 1987 and contained some pesticide residues The significance of these findings will be discussed and related to potential environmental toxicological effects Severe grasshopper infestations in 1985 and 1986 resulted in insecticide treatments in the study area Water samples were tested for the insecticides carbofuran, carbaryl, chlorpyrifos, dimethoate, and deltamethrin Three samples of spring runoff, collected from one site in 1987, contained approximately 1 ppb carbofuran All other samples were less than the detection levels
Biodehalogenation: The metabolism of vinyl chloride byMethylosinus trichosporiumOB-3b. A sequential oxidative and reductive pathway through chloroethylene oxide
Authors: Castro C.E. , Riebeth D.M. , Belser N.O.
Published: March 2010

Resting cell suspensions of the soil methylotroph Methylosinus trichosporium OB-3b rapidly metabolize vinyl chloride The half-life of the reaction, based on Cl release at pH 7 4, 0 1 in phosphate buffer with a cell density of 0 1 g/ml, is 0 61 h The path of metabolism is complicated but proceeds through the intermediacy of chloroethylene oxide Independent studies of the hydrolysis of this oxirane in water set its chemical half life at 3 9 min The products of its reaction with water are chloroacetaldehyde and hydroxyacetaldehyde They are produced in a ratio of 2 1, as judged by Cl release and 1H and 13C nuclear magnetic resonance analysis Incubations with vinyl chloride 1,2-13C and vinyl chloride 1,2 14C establish that the dominant metabolic pathway entails a quick reduction of chloroethylene oxide to ethylene oxide Ethylene oxide is then converted in sequence to ethylene glycol, hydroxyacetaldehyde, glycolic acid, and CO2 This process is competitive with the chemical hydrolysis of chloroethylene oxide Similarly, chloroacetaldehyde is con verted to chloroacetic acid The latter is only slowly metabolized by this organism, and it accumulates throughout incubation to a final yield of 10% It is concluded that the organism participates in the hydrolysis of both chloroethylene oxide and ethylene oxide
Biodehalogenation: Rapid metabolism of Vinyl Chloride by a soilPseudomonassp. Direct hydrolysis of a vinyl CCl bond
Authors: Castro C.E. , Wade R.S. , Riebeth D.M. , Bartnicki E.W. , Belser N.O.
Published: March 2010

Resting cell suspensions of a soil Pseudomonas sp readily metabolize vinyl chloride Studies with a combination of 13C and 14C labeled vinyl chloride and metabolites establish that the initial dehalogenation step formally entails a direct hydroxylation of the CCl bond to produce acetaldehyde This substance undergoes biochemical oxidation at both the carbonyl and the methyl carbons to produce acetic acid and hydroxyacetaldehyde These are both further oxidized by the organism to hydroxyacetic acid (glycolic acid), and the latter is converted to carbon dioxide The rate of Cl liberation from vinyl chloride is a function of growth conditions Cells grown on 3 chloropropanol carry out the dehalogenation of vinyl chloride with a t1/2 of 1 3 h at a cell density of 0 1 g/ml
Variability in the performance of the 7-dCeriodaphnia dubiasurvival and reproduction test: An intra- and interlaboratory study
Authors: Degraeve G.M. , Cooney J.D. , Marsh B.H. , Pollock T.L. , Reichenbach N.G.
Published: March 2010

The U.S. Environmental Protection Agency (EPA) has developed a 7-day Ceriodaphnia dubia survival and reproduction test for measuring the toxicity of effluents. This study evaluated the ease of performance and the intra- and interlaboratory variability of this 7-d test, using two reference toxicants (sodium chloride and potassium dichromate), two pulp and paper effluents, and two utility effluents Eleven different laboratories, representing academia, private industry, contractors, and the state EPA and federal EPA, participated in the study. The reference toxicants were tested twice during two separate test periods, and each industrial effluent was tested once. Using the EPA's criteria for a successful test (®80% survival and ® 15 young per female in controls), 56% of the 116 planned tests were completed as valid tests. Most tests were invalid because the laboratories were unable to initiate the tests successfully or because control survival was <80%. Seventy-eight percent of the tests that were initiated were successfully completed. Reproduction no-observed-effect-concentration (NOEC) values were generally somewhat lower than those for survival but had greater variability than survival NOEC values. The interlaboratory variability of the survival (LC50) and reproduction (IC50) results, expressed as the C V., ranged between 29.8 and 30.8% and between 28.9 and 39.0%, respectively. The study demonstrated that about half (56%) of the laboratories participating in the study were able to routinely complete the test successfully. Some of the laboratories experienced with other effluent toxicity tests were less prepared to complete this test successfully. Overall, the variability of the 7-d Ceriodaphnia tests that were completed was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.
Residue-based interpretation of toxicity and bioconcentration QSARs from aquatic bioassays: Neutral narcotic organics
Authors: McCarty L. S. , Dixon D. G. , MacKay D. , Smith A. D. , Ozburn G. W.
Published: March 2010

The critical body residue (CBR), estimated from aquatic toxicity QSARs and bioconcentration-log Kow relationships, appears to be relatively constant, at about 4 mmol L−1 of fish, for the acute toxicity of a variety of hydrophobic narcotic organic chemicals examined by the U.S. Environmental Protection Agency (Duluth, MN) in tests with the fathead minnow. However, for hydrophilic chemicals (log Kow < 1.5) the bulk of the toxicant is in the water phase rather than the organic/lipid phase of the organism, so the whole-body residues in these cases should be similar to the LC50 water concentration. Over the log Kow range of – 1.5 to 6, acutely toxic whole-body residues for narcotics can be approximated by the QSAR-derived equation: CBR (mM) = 2.5 mM + 50/Kow. Estimates obtained by this method are in reasonable agreement with the limited literature data available for acutely toxic whole-body residues of hydrophobic narcotic organic chemicals. Elimination half-lives estimated from nonlinear curve fitting to time-toxicity information were relatively constant for the Duluth bioassay data at approximately 3 h. Despite the relatively high variability of this type of kinetics data, the literature information for small aquatic organisms, from both toxicity-and bioconcentration-based tests, was in a similar range. It appears that QSARs created with raw aquatic bioassay data occur primarily as a result of the influence of chemical-physical properties on the partitioning process. Log Kow appears to have little to do with the inherent potency of the neutral, narcotic organic chemicals examined.
Quantitative analysis of structure-toxicity relationships of substituted anilines by use of Balb/3T3 cells
Authors: Harada Akihisa , Hashimoto Kazuo , Hanzawa Masahiko , Saito Jun
Published: March 2010

The acute toxicities of 24 substituted anilines in terms of 50% inhibition concentrations (150) for viability of cells and their adenosine triphosphate (ATP) content were measured with monolayer cultures of Balb/3T3 cells. The quantitative relationship (QSAR) was analyzed for the pI50 (viability) value with physicochemical substituent parameters. The pI50 (viability) value of substituted anilines was parabolically related with log P, P being the 1-octanol/water partition coefficient, where electronic and hydrogen bonding effects were separately considered. There was a good correspondence between pI50 values for cellular viability and ATP content. None of the test compounds, however, showed any specific depletion of cellular ATP content, suggesting that substituted anilines do not specifically damage the energy metabolism of the cells.
A simple stream-side test system for determining acute lethal and behavioral effects of pesticides on aquatic insects
Authors: Kreutzweiser David P. , Capell Scott S.
Published: March 2010

A stream-side test system was developed to measure direct lethal and behavioral effects of pesticides on stream insects under simulated natural conditions. The system allowed for quantitative analysis of drift response to pesticide exposure (proportion of test species that drifted), drift profile (drift response over time), survival of displaced insects, and survival of test species remaining in the substrate. The design, procedure, analysis, and advantages of this system are presented.
Sublethal effects of cadmium on physiological responses in the pocketbook mussel, Lampsilis ventricosa
Authors: Naimo Teresa J. , Atchison Gary J. , Holland-Bartels Leslie E.
Published: March 2010

Recent studies indicate that the density and diversity of freshwater mussels are declining in many large river systems, possibly from low-level chemical contamination. Exposure of Lam-psilis ventricosa (Barnes, 1823) to 0, 22, 111, and 305 μg/L of cadmium for 28 d in a proportional diluter resulted in a significant decrease (p ≤ 0.05) in respiration rate as cadmium concentration increased. Although variations in cadmium concentrations did not significantly affect food clearance rates or ammonia excretion rates, mussels exposed to 305 μg cadmium per liter showed a decrease in ammonia excretion rates and a decrease in food clearance rates over the 28-d study. Assimilation efficiencies increased during the test in all treatments. Oxygen-to-nitrogen ratios were significantly increased in mussels exposed to either 111 or 305 μg cadmium per liter by day 28. Tissue condition index (TCI) values were significantly lower in mussels in the toxicity test than those in a field sample. The significant change in respiration rate after only a 28-d exposure to cadmium suggests that freshwater mussels may be sensitive indicators of sublethal contaminant exposure. However, the large variability in other physiological responses indicates that the study of contaminant effects requires careful selection of appropriate physiological indicators.