bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary accumulation of four chlorinated dioxin congeners by rainbow trout and fathead minnows
Authors: Muir Derek C. G. , Yarechewski Alvin L.
Published: March 2010

Accumulation of four 14C-labeled polychlorinated dibenzo-p-dioxins (PCDDs), 1,2,3,7-T4CDD, 1,2,3,4,7-P5CDD, 1,2,3,4,7,8-H6CDD, and 1,2,3,4,6,7,8-H7CDD, by juvenile rainbow trout (Salmo gairdneri) and fathead minnows (Pimephales promelas) was studied by feeding the fish treated food for 30 d followed by a 30- to 75-d depuration period. Assimilation efficiencies (based on total 14C) of the isomers were low, ranging from 13% for H7CDD to 37% for H6CDD in trout, as compared with 64% for 4,4′-DDT under the same conditions. Bioaccumulation factors, assimilation efficiencies and elimination rate constants for each PCDD congener were lower in fathead minnows than in rainbow trout. Half-lives for total 14C ranged from 9 to 13 d for T4CDD and P5CDD in trout and minnows, respectively, and from 46 to 112 d for H6CDD and H7CDD in the same fish. Toluene-extractable radioactivity for T4CDD and P5CDD was less than 30% during the clearance phase, indicating extensive transformation to polar products in both species. A four-compartment model was used to estimate the accumulation of H6CDD and H7CDD in Great Lakes food chains (from detritus/phytoplankton to lake trout). The model predicted decreasing concentrations of the PCDDs at higher trophic levels, with accumulation primarily from food, assuming freely dissolved water concentrations of less than 2 × 10−5 ng L−1.
Potential hazard to eastern screech-owls and other raptors of brodifacoum bait used for vole control in orchards
Authors: Hegdal Paul L. , Colvin Bruce A.
Published: March 2010

During the fall and winter of 1981–82, a study was conducted to evaluate the secondary poisoning hazards associated with a proposed anticoagulant rodenticide, Volid® (10 ppm brodifacoum), when used to control voles (Microtus spp.) in apple orchards. Radio transmitters were attached to 38 eastern screech-owls (Otus asio), 5 barred owls (Strix varia), 3 red-tailed hawks (Buteo jamaicensis), 2 great horned owls (Bubo virginianus) and 2 long-eared owls (Asio otus), and the birds' movements were monitored before, during, and after rodenticide applications. Screech-owls selected woods over alternate habitats for day-roosting; 73% of daytime locations were in woods. At night, screech-owls generally were located in woods, orchard, and field-pasture proportional to their availability, while they avoided cropland. The home ranges of 32 screech-owls tracked posttreatment included brodifacoum-treated areas; the proportion of home range treated and habitat use varied among individuals. Minimum mortality was 58% among screech-owls for which more than 20% of home range was treated, as compared with 17% among those for which less than 10% of home range was treated. Secondary brodifacoum poisoning was the most probable cause of death in six screech-owls. Of five other screech-owls found dead posttreatment, four had been consumed by predators and one died of unknown causes. Of six radio-equipped screech-owls collected one to two months posttreatment, four contained detectable brodifacoum residue. The fate of 14 of the 32 screech-owls tracked posttreatment was unknown at the conclusion of radiotracking efforts (63 d after treatment began) because radio contact was lost or the transmitter was dropped; one of these owls was encountered alive in May. Four barred owls tracked posttreatment showed strong selection for woodland habitat and used orchards limitedly; none was found dead posttreatment. One long-eared owl found dead (not radio-equipped) was probably killed by secondary brodifacoum poisoning. The results indicate a hazard to screech-owls and a potential risk to other raptors, given this use pattern and formulation of brodifacoum bait.
Alterations in the oxygen consumption, condition index and concentration of free amino acids in Corbicula fluminea, (mollusca: Pelecypoda) exposed to sodium dodecyl sulfate
Authors: Graney Robert L. , Giesy John P.
Published: March 2010

The freshwater clam, Corbicula fluminea, was exposed during short- and long-term toxicity tests to the anionic surfactant sodium dodecyl sulfate (SDS). Oxygen consumption, condition index, water content and the concentration of free amino acids (FAA) were measured in the clams after exposure. A significant increase in the total FAA concentration was measured in clams exposed for 96 h to 25 mg/L SDS. Exposure to sublethal concentrations (0.65 and 3.0 mg/L SDS) for 60 d caused both an increase in total FAA concentration and a change in the relative concentrations of individual amino acids. Sublethal chronic exposure also decreased oxygen consumption and condition index and increased water content. Alterations in FAA are a more sensitive indicator of toxicant exposure than more traditional measures such as respiration. The potential use of FAA as an in situ biochemical indicator of toxicant-induced stress in freshwater invertebrates is discussed.
Effect of cadmium on early developmental stages of the sheepshead minnow (Cyprinodon variegatus)
Authors: Meteyer Marc J. , Wright David A. , Martin F. Douglas
Published: March 2010

Cadmium uptake by the early developmental stages of the sheepshead minnow, Cyprinodon variegatus, was studied over a 7.5-d post-hatch period. After chorionic hardening (about 4 h after fertilization), eggs were placed in filtered water from the Patuxent River, Maryland (diluted to 5%90 salinity), and dosed with cadmium concentrations of between 0.39 and 1,020 μg L−1. At the highest cadmium concentrations studied, hatching was delayed up to 3 d and larvae had spinal deformities. Growth inhibition was not clearly dose-related, although larvae from all cadmium treatments were significantly shorter than controls. The lowest dry weights were recorded from the 5.8 and 1,020 μg Cd L−1 treatment groups. Cadmium uptake peaked at 12 h after fertilization. Calcium levels in eggs and yolk-sac larvae reared in 446 μg Cd L−1 were greater than in controls after the first 2 d of development but fell behind thereafter, reaching only 50% of the control calcium level after 7.5 d. Inhibition of calcium uptake persisted even after cadmium levels had peaked and fallen to the control level. Phosphorus and sodium concentrations in eggs and larvae were not affected by cadmium exposure. Ninety-three percent of the cadmium accumulated by the egg was associated with the chorion, and 68% of this could be removed by a glycine buffer.
Effects of agricultural spraying of methyl parathion on cholinesterase activity and reproductive success in wild starlings (Sturnus vulgaris)
Authors: Robinson Suzanne C. , Kendall Ronald J. , Robinson Rex , Driver Crystal J. , Lacher Thomas E.
Published: March 2010

In June 1984, methyl parathion (phosphorothioic acid, O, O-dimethyl O-[4-nitrophenyl] ester) was applied at 1.4 kg a.i./ha to a cultivated field in Skagit Valley, Washington. Brain cholinesterase (ChE) activity was determined in adult and nestling starlings (Sturnus vulgaris) in artificial nesting boxes on the peripheries of a treated and a control field for up to 1 week following application of the pesticide. Brain ChE activities in nestling starlings from the control field increased linearly from age 6 to 19 d. Brain ChE levels in chicks taken from the treated fields were more variable. From the treatment field, 92% of adults collected up to 7 d posttreatment exhibited marked depressions of brain ChE, while during the same period, 29% of the nestlings showed similar responses. A significant correlation was demonstrated between the levels of brain ChE depression in adult and in the nestling starlings collected from the same nests.

Measures of reproductive success (i.e., hatching of eggs and fledging of young) were also determined in a portion of the nestboxes to assess any potential adverse effects. The spraying of methyl parathion did not significantly reduce hatchability of the starling eggs. The mean (±SE) number of young fledged per nest on the sprayed field, 2.22 ± 0.29, was not significantly different from that on the control site, 3.33 ± 0.17. However, collectively, the number of nestlings fledging from the treatment field postspray was significantly lower than from the control field.
Organochlorine and mercury residues in wild mink and otter: Comparison with fish
Authors: Foley Robert E. , Jackling Samuel J. , Sloan Ronald J. , Brown Mark K.
Published: March 2010

Organochlorine and mercury levels in wild mink (Mustela vison) and otter (Lutra canadensis) from eight areas of New York State were measured in adipose and liver tissues. Polychlorinated biphenyl (PCB) compounds, quantified as Aroclor 1254/1260 and p,p'-DDE, were detected in all animals. Significantly greater concentrations of organochlorines in both species were associated with habitat known to be contaminated with PCB (Hudson Valley and within 5 mi of Lake Ontario). Wet-weight PCB concentrations in adipose tissue of mink and otter from the more contaminated areas ranged as high as 67 and 114 μg/g, respectively. PCB levels in wild mink are similar to those that caused reproductive problems in other controlled feeding studies. Mercury concentrations in liver tissue were similar in both species (mean, 2.2 and 1.8 μg/g wet weight in mink and otter, respectively).

Comparisons of the mink and otter body burdens with data for fish from New York's statewide Toxic Substance Monitoring Program were made. To test the hypothesis that organochlorine contaminant concentrations in mink and otter are related to environmental levels, collection locations of fish were paired with those of mink or otter on the basis of the size of the home range of the respective mammal. Correlations between fish and both mammalian species were significant for PCB and p,p'-DDE when fish and mustelid collection stations were between 10 and 20 km apart. Correlations for mercury in fish and mustelids were significant only on the basis of major watershed.
Effects of methyl parathion in ducks and duck broods
Authors: Brewer Larry W. , Driver Crystal J. , Kendall Ronald J. , Zenier Carol , Lacher Thomas E.
Published: March 2010

Nesting ducks (mallards, blue-winged teal, cinnamon teal and wood ducks) were trapped, equipped with radio transmitters and released on two agricultural fields, both of which were bordered by waterways. One field was aerially treated with methyl parathion at the rate of 1.4 kg active ingredient (a.i.)/ha and the second field was an untreated control. Ducks were located with the aid of radiotelemetry after pesticide application and their activity monitored daily in both fields. Brood abandonment by hens and nesting hen mortality occurred only on the methyl-parathion-treated field postspray. Brain cholinesterase levels were significantly depressed in two of three nesting hens. Fifty-eight percent of the 37 ducklings present in the control field on the day of spray survived to day 22 postspray. Sixteen percent of the 24 ducklings present in the treated field on the day of spray survived to day 22. The average daily rate of duckling loss was also greater in the treated field than in the control field. Nest abandonment rates could not be correlated with methyl parathion application.
Structure-stability relationships of metal complexes and metal speciation in environmental aqueous solutions
Authors: Martell Arthur E. , Motekaitisand Ramunas J. , Smith Robert M.
Published: March 2010

The methods employed to determine critical stability constants from the published literature are described and the best approach for estimating stability constants to establish a sufficiently broad and extensive database that substantially defines all of the metal complex systems encountered in the environment is recommended. With these estimated formation constants, it is possible, with modern computer techniques, to calculate the speciation and concentrations of the metal complexes in multicomponent systems containing thousands of ligands and 10 to 100 times that number of metal complex species. The structure-stability relationships developed by other investigators are compared with the methods employed herein. Examples of measured, selected and estimated constants are presented for several metal complexes. The distributions of metal complex species in seawater in the absence and presence of an added complexing pollutant are calculated to illustrate the use of the stability constant database and the adjustment of the constants to the conditions required (i.e., ionic strength) for the system under consideration.
Structure-activity relationships for selecting and setting priorities for existing chemicals — a computer-assisted approach
Authors: Klein Albrecht W. , Klein Werner , KÖrdel Werner , Michael Weiss
Published: March 2010

The incorporation of structure-activity relationships and other estimation methods in a computer format is a logical and necessary step in handling the complex problem of setting priorities for existing chemicals in a feasible, systematic way. In combination with an appropriate hazard ranking methodology, the computer format is a useful tool for selecting existing chemicals for further testing and more detailed assessment. Recent developments and applications of a proposed system for setting priorities for existing chemicals are discussed, along with the system's expected reliability and limitations. Important gaps that now exist in our understanding of the relationships between structure and physicochemical and toxicological properties, as well as reactivities, are pointed out. Selected chemicals are cited in examples of the application of the new computer-assisted methodology.
Comparison of three sediment bioassay methods using detroit river sediments
Authors: Giesy John P. , Graney Robert L. , Newsted John L. , Rosiuand Cornell J. , Benda Ann , Kreis Russell G. , Horvath Frank J.
Published: March 2010

The relative sensitivities and discrimination abilities of the Daphnia magna 48-h lethality assay of sediment pore water, the Photobacterium phosphoreum 15-min bioluminescence inhibition (Microtox®) assay of sediment pore water and the Chironomus tentans 10-d growth reduction assay of whole Detroit River sediments were investigated and predictive relationships developed. While all three assays demonstrated the toxicity of some sediments and all of them identified the most and least toxic sediments, the D. magna lethality assay was the least sensitive and discriminatory. The Microtox® assay was the most sensitive. Based on lethality, the C. tentans assay was less sensitive than D. magna, but growth inhibition was sensitive and the most discriminatory of the three assays. Chironomids were not observed in the sediments that caused a 30% decrease in growth of C. tentans relative to that on control sediment in which chironomids were observed. This sediment toxicity is also approximately that which kills D. magna. Some locations were deemed very toxic by one or two assays but not toxic by the others. The results of all of the assays were correlated, but none of the assays accurately predicted the results of the other two. It was concluded that the D. magna lethality test could be used to predict which sediments were so toxic that benthic insects would not be expected to be present. A principal components analysis demonstrated that the Microtox® assay gave sufficiently different information that it could be included in a battery of sediment toxicity tests designed to accurately classify the toxicities of sediments.
Comparative sensitivities of bluegill, channel catfish and fathead minnow to pH and aluminum
Authors: Palmer Robert E. , Klauda Ronald J. , Lewis Timothy E.
Published: March 2010

Sensitivities of bluegill (Lepomis macrochins), channel catfish (Ictalurus punctatus) and fathead minnow (Pimephales promelas) to pH and aluminum were compared during 96-h acute toxicity tests in the laboratory. Juveniles were exposed to four HCl (pH 4.5, 5.5, 6.5, 7.5 nominal) and five AlCl3 (0, 50, 100, 200, 400 μg/L nominal) treatments in moderately soft fresh water (total hardness, 20 to 25 mg/L CaCO3) under continuous flow-through conditions. The ranking of species sensitivities to acid alone was fathead minnow (most sensitive), followed by channel catfish and bluegill (about equally sensitive). Aluminum was not toxic to these species at pH 6.5 and 7.5. The ranking of sensitivities to Al at pH 4.5 and 5.5 showed clearer species differences. Fathead minnow were most sensitive and died in all Al treatments. Bluegill were least sensitive and died only in the highest Al concentration at pH 5.5. The sensitivity of channel catfish to Al was intermediate, but was most similar to that of fathead minnow. Aluminum, predominantly as hydroxide species, appeared to be most toxic to bluegill at pH 5.5. Free and hydroxy Al species were apparently toxic to fathead minnow and channel catfish at pH 4.5 and 5.5. Our experimental data corroborate the observed distributions of these species in acidified lakes and streams.
Simulation of the aquatic fate of triclopyr butoxyethyl ester and its predicted effects on coho salmon
Authors: McCall Philip J. , Laskowski Dennis A. , Bidlack Harvey D.
Published: March 2010

Mathematical simulations of the dissipation of triclopyr butoxyethyl ester in a model aquatic system representing a shallow, static pond were conducted. Aqueous hydrolysis, sorption to bottom sediment, hydrolysis in sediment and photolysis were considered in predicting aqueous concentration-time profiles. Potential concentrations in Coho salmon were evaluated as part of the model based on rate constants for uptake, hydrolysis and elimination as determined in laboratory investigations conducted in another study. Predicted chemical concentrations in the fish were then related to toxicity data to estimate aqueous concentrations in the model environment required to give a toxic response. In general, the simulations showed that the ester concentration in the pond water would decline, with an approximate half-life of 6 to 24 h. Initial ester concentrations of 1.0 to 1.5 mg/L in this simulated pond environment would be required to result in chemical concentrations in fish above toxic threshold levels.
Chemical characterization and mutagenic properties of polycyclic aromatic compounds in sediment from tributaries of the great lakes
Authors: Fabacher David L. , Schmitt Christopher J. , Besser John M. , Mac Michael J.
Published: March 2010

Sediments from four inshore industrial sites and a reference site in the Great Lakes were extracted with solvents and characterized chemically for polycyclic aromatic compounds (PACs). An aqueous phase and a crude organic extract were obtained. The crude organic extract was further resolved into fractions A-2 (polycyclic aromatic hydrocarbons) and A-3 (nitrogen-containing polycyclic aromatic compounds), which were analyzed for PACs by gas chromatography and gas chromatography-mass spectrometry. The extracts and fractions were tested for mutagenicity in three assays: Ames, rat hepatocyte unscheduled DNA synthesis, and Chinese hamster ovary hypoxanthine-guanine phosphoribosyl transferase (CHO/HGPRT). Sediments from the industrial sites contained 27 to 363 μg/g total PACs; the reference site, less than 1 μg/g. Qualitative differences in the residue profiles among the sites were attributable to the probable sources of the PACs (petroleum versus combustion). Only one industrial site yielded measurable (0.1 μg/g or more) concentrations of individual nitrogen-containing PACs. In the Ames assay, only the highest doses of the A-2 fractions from two sites approached positive results. Conversely, the crude organic extract and A-2 and A-3 fractions from all sites induced unscheduled DNA synthesis. Crude organic extracts and the A-2 and A-3 fractions from all industrial sites gave well-defined dose-response relations in the CHO/HGPRT assay. We established the presence of chemical mutagens in sediment that could be correlated with neoplasms in fish from many of the sites; however, the mutagenicity of the sediment extracts was not completely related to the degree of contamination by PACs. We also discuss the utility of mutagenicity assays in the evaluation of complex chemical mixtures and recommend the use of a CHO/HGPRT-type assay in which cells are not required to proliferate in the presence of potential interfering chemicals.
Dissolved organic macromolecules reduce the uptake of hydrophobic organic contaminants by the gills of rainbow trout (Salmo gairdneri)
Authors: Black Marsha C. , McCarthy John F.
Published: March 2010

The effect of the binding of two model hydrophobic organic contaminants, benzo[a]pyrene and 2,2′,5,5′ -tetrachlorobiphenyl, to Aldrich humic acid, a commercially available source of dissolved organic macromolecules (DOM), on the uptake of these contaminants by the gills of rainbow trout (Salmo gairdneri) was examined. The efficiency with which trout gills extracted the contaminants from water (with and without DOM present) was measured using a fish metabolic chamber that separated exposure water from water that passed over the gills. Measurements of the contaminant extraction efficiency of trout gills were compared with measurements of contaminant binding to DOM. Contaminants bound to DOM did not diffuse across the gill membrane. Percentage reductions in the concentration of freely dissolved contaminant were equal to percentage reductions in the uptake of the contaminant by the gills. Thus, only the freely dissolved contaminant appears to be available for uptake by fish gills. These correlations between the concentration of freely dissolved contaminant and the fraction of the exposure concentration that is transferred across the gills provide a basis for predicting contaminant dose based on physicochemical measurements of contaminant binding to naturally occurring DOM in the aquatic environment.
A physiological study of the effects of triton surfactants on Lemna minor L.
Authors: Caux P. Y. , Weinberger P. , Carlisle D. B.
Published: March 2010

Adjuvants significantly contribute to many commercial herbicide/pesticide formulations and are often present at concentrations approaching those of the active ingredient. The Canadian Forest Service is currently testing alkyl aryl polyether alcohol adjuvants as “acceptable” replacement surfactants in the fenitrothion formulation used to control the spruce budworm, Choristoneura fumiferana. This study describes the toxic effects of these compounds on a common and widespread aquatic vascular plant, Lemna minor L.

The parameters monitored during the 14-d exposure included growth (biomass), frond fluorescence and chlorophyll content, conductivity of the test media and specific ion leakage. At 1 μg/ml, no response of any of the monitored parameters was observed for any of the Tritons, and 10 μg/ml resulted in no response for Triton X-114. Exposure to 10 μg/ml of the other Tritons tested, however, resulted in toxic effects such that frond development was depressed 25 to 50%. Exposure to 50 μg/ml of the lower ethoxylates, Tritons X-l5 and X-35, elicited approximately twofold greater depression of the parameters assessed than did treatments with comparable concentrations of the higher ethoxylates, Tritons X-100 and X-114. A positive correlation was obtained between the degree of phytotoxicity and the hydrophilie-lipophilic balance (HLB), and partition coefficients for the Triton surfactants.
Effects of chlorine on microbial communities in naturally derived microcosms: Population and community level responses to environmental perturbations
Authors: Pratt J. R. , Bowers N. J. , Niederlehner B. R. , Cairns J.
Published: March 2010

Laboratory microcosms and field enclosures were used to evaluate effects of chlorine on microbial community structure and function. Microcosms were exposed to chlorine (as sodium hypochlorite) at concentrations up to 308 μg/L total residual chlorine (TRC) for 28 d. Test systems were sampled weekly to evaluate protozoan species accrual, biomass distribution, microbial enzyme activity, and macronutrient retention. Protozoan species numbers were depressed at all sampling times at TRC concentrations ≥25 μg/L. Algal biomass (chlorophyll a) was adversely affected at 2 μg/L, and alkaline phosphatase activity was inhibited at ≥6 μg/L. Other biomass measures and macronutrient retention were affected at 25 to 308 μg/L. Oxygen production was depressed at ≥25 μg/L. Field enclosures (sediment-water mesocosms) were dosed daily with chlorine, resulting in average chlorine doses up to 261 μg/L. Protozoan species numbers were depressed at chlorine doses ≥79 μg/L, and zooplankton density was affected at 24 μg/L. Algal biomass and total biomass were adversely affected at the highest chlorine level, 261 μg/L. Nontaxonomic measures were typically less sensitive than community structure responses to chronic chlorine stress. Estimated effect levels for both experiments overlapped; however, the response of specific variables (i.e., stimulation, inhibition, no effect) to chlorine differed between the two tests. These results support the importance of experimental design and dosage regime in chronic toxicity testing.
Using stream survey data to predict directional change in fish populations following physicochemical stream perturbations
Authors: Layher William G. , Maughan O. Eugene
Published: March 2010

Standing stocks of fish species were graphed against 30 abiotic variables measured in Kansas streams. The resulting habitat suitability curves for each variable allowed fish biomass to be normalized to index values that could be regressed linearly against these variables. Stepwise multiple-regression techniques isolated variables that accounted for much of the biomass of individual populations. Regression models applied to an independent data set from Oklahoma produced highly significant (though low) correlations between predicted and observed standing stocks. Assigning suitability index values to Oklahoma streams from curves developed with Kansas data identified other variables as limiting, thus explaining much of the biomass variation. This analysis indicated that the habitat suitability curves approximated fish population changes along a single-variable axis. Kansas stream data has been placed in a statistical data set and provided with visual display. The system allows for rapid assessment of the effects of changes in 30 physicochemical variables on populations of about 100 fish species in Kansas streams.
Structural alterations in aquatic insect communities exposed to copper in laboratory streams
Authors: Clements William H. , Cherry Donald S. , Cairns John
Published: March 2010

The effects of copper on aquatic insect communities were examined using rock-filled trays colonized in the field for 30 d, transferred to laboratory streams, and dosed with CuSO4. Each stream was randomly assigned to one of three treatments: control (0 μg/L), low dose (15–32 μg/L), and high dose (135–178 μg/L). Experiments were replicated over three seasons. Exposure to copper for 96 h significantly reduced both the total number of individuals and number of taxa during each season, with greatest effects observed in summer. Owing to differences in sensitivity to copper, the percent composition of dominant orders of aquatic insects varied among treatments. The relative abundance of Ephemeroptera decreased in treated streams during each season. The response of other aquatic insects, including Diptera and Plecoptera, varied between seasons, but these groups were generally less sensitive to copper exposure. These results indicate that the artificial substrates employed in this study are amenable to experimental manipulation and will provide a unique opportunity to examine the community responses of aquatic insects to toxicants under environmentally realistic conditions.
Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography
Authors: Belisle Andre A. , Swineford Douglas M.
Published: March 2010

A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetonermethylene chloride (1:1, v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93% for sediments extracted shortly after spiking, but decreased significantly as the samples aged.
Soil biodegradation of carbofuran and furathiocarb following soil pretreatment with these pesticides
Authors: Hendry Karen M. , Richardson Curtis J.
Published: March 2010

A field application level (9 μg·g−1) of carbofuran was completely hydrolyzed within 1 to 3 days in a loamy sand soil pretreated with the same level of carbofuran, while <5% of the carbofuran was hydrolyzed in control soil not pretreated. The number of microbial carbofuran-hydrolyzers was substantially greater in loamy sand soil treated twice with a field application level (9 μg·g−1) of carbofuran than in untreated soil. Also, carbofuran-adapted soil showed no significant change in the number of carbofuran-hydrolyzers during the period of rapid degradation. Inorganic nitrogen, at a typical fertilization level, appeared to slightly stimulate the enhanced degradation of carbofuran in the pretreated soil. Soil pretreated with an application level hydrolyzed 65% of a residue level (8 ng·g−1) within two days, but virtually none of the remaining carbofuran was hydrolyzed thereafter. A microbial biomass carbon experiment with a sandy loam soil indicated that only 0.2% of the applied carbonyl-C could be attributed to biomass. Soil pretreated with a residue level did not show rapid degradation of the same level or a field application level, although the field application level was degraded slightly faster in this soil than in soil not pretreated. Soil pretreated with a field application level of carbofuran or furathiocarb also rapidly hydrolyzed the same level of furathiocarb, but furathiocarb is probably converted into carbofuran before hydrolysis.
Relationships among models for acute toxic effects: Applications to fluctuating concentrations
Authors: Breck James E.
Published: March 2010

A damage-repair model for estimating mortality due to fluctuating exposures reduces to the probit plane model for short exposure times or negligible repair rates. Interpreting the probit plane as a cumulative damage model, data from constant exposures may be useful for predicting mortality due to fluctuating exposures of short duration.
Nonequilibrium sorption of organic contaminants during flow through columns of aquifer materials
Authors: Lee L. S. , Rao P. S. C. , Brusseau M. L. , Ogwada R. A.
Published: March 2010

Batch equilibrium and miscible displacement studies were conducted to investigate sorption and transport of trichloroethylene (TCE) and p-xylene in two sand aquifer materials low in organic carbon content. The utility of a bicontinuum (two-site) sorption model to describe the extent of sorption nonequilibrium during transport in saturated columns was evaluated. Model parameters estimated from the breakthrough curves (BTC) obtained at a high pore-water velocity (v = 24 cm/h) were used successfully to describe the BTC measured at a lower pore-water velocity (v = 6 cm/h). The assumption of local sorption equilibrium was valid at the lower velocity, and the measured BTC could be described by an equilibrium sorption model coupled to a convective-dispersive transport model. Values for column retardation factors estimated by fitting the two-site model to the BTC were comparable with those estimated from equilibrium sorption isotherms. BTC measured for displacement of binary mixtures (TCE plus p-xylene) and single-solute (TCE or p-xylene alone) were identical, suggesting that there is no competitive sorption between these two solutes. These column observations were consistent with sorption isotherm data.
Laboratory acidification of a crustacean zooplankton assemblage from a Rocky mountain subalpine lake (U.S.A.)
Authors: Bruns D. A. , Wiersma G. B.
Published: March 2010

A laboratory acidification experiment was conducted with a Rocky Mountain zooplankton assemblage from a subalpine lake located downwind of energy development activities and significant sources of acid precursors. The objective of the study was to assess the relative effects of lowered pH (treatment pH 4.2 and 5.2, control pH 6.8) on the survival of different crustacean zoo-plankton species under controlled conditions for extended periods (19 to 41 d). Analysis of variance (e.g., F = 4.55, p < 0.05) indicated statistically significant differences between controls and treatments (acid treatments contained fewer individuals than did controls) for all four species, and significant differences among species. Newman-Keuls multiple range tests (e.g., q = 4.02, p < 0.025) demonstrated the following ranking of species sensitivity (high to low) to a lowered pH of 5.2: Daphnia rosea > Holopedium gibberum > Diaptomus lintoni > Cyclops sp. At pH 4.2, H. gibberum was significantly more tolerant than D. rosea and D. lintoni (q = 4.50, p < 0.025), but no other significant differences were apparent. The results agree generally with those of other published experiments and field surveys.
Porphyria in herring gulls: A biochemical response to chemical contamination of great lakes food chains
Authors: Fox Glen A. , Norstrom Ross J. , Wigfield Donald C. , Kennedy Sean W.
Published: March 2010

Concentrations of highly carboxylated porphyrins (HCPs) in the livers of adult herring gulls (Larus argentatus) from colonies throughout the Great Lakes were found to be markedly elevated in comparison with those in gulls from coastal areas and in seven other species of birds consuming diets uncontaminated with polyhalogenated aromatic hydrocarbons (PHAHs). The highes levels were found in gulls from lower Green Bay (Lake Michigan), Saginaw Bay (Lake Huron) ant Lake Ontario. We suggest that the high levels of HCPs reflect PHAH-induced derangement of heme biosynthesis. Determination of HCPs offers promise as a specific and sensitive biological marker of PHAH-induced toxicity and as a measure of the toxicological significance of the chemical burden in gulls, terminal members of Great Lakes food chains.
Effect of low-level continuous chlorination on Corbicula fluminea
Authors: Ramsay George G. , Tackett J. Hainey , Morris David W.
Published: March 2010

The time required for continuous chlorination to produce 100% mortality in adult Corbicula fluminea was determined. The total residual chlorine concentrations maintained were lower than any previously tested: 0.05, 0.10 and 0.20 mg/L.
Improvement and application of an immunoassay for screening environmental samples for dioxin contamination
Authors: Vanderlaan Martin , Stanker Larry H. , Watkins Bruce E. , Petrovic Peter , Gorbach Siegbert
Published: March 2010

We previously had developed monoclonal antibodies for the immunoassay of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), and have since refined the use of these antibodies for the detection of dioxins in a wide range of contaminated samples, with the aim of developing a screening assay for dioxin contamination. The levels of PCDD and PCDF contamination in 13 different samples, including fly ash, soil, technical-grade chemicals, motor oils, polychlorinated biphenyl transformer oil and still-bottom residues, were determined by immunoassay. The contamination ranged from less than 1 to several thousand ppb PCDD and PCDF. The levels of PCDD and PCDF contamination in some samples were determined by conventional GC-MS. The monoclonal antibodies used in this study detect many of the tri-, tetra- and pentachloro congeners of PCDD and PCDF, while the GC-MS data included information on total tetra- and pentachloro congeners of PCDD and PCDF, as well as levels of specifically regulated toxic congeners. There were good correlations between the results of the immunoassay and those of conventional GC-MS analysis, in spite of the differences in the exact congeners detected by the two techniques. There were no false-negative results. Moreover, the immunoassay required substantially less sample cleanup than did GC-MS, thus offering the promise of greatly reduced costs and time for screening samples. Only the soil matrix interfered with results; the cleanup methods for this matrix still need improvement.
Utilization of microcomputer and telecommunications technologies in the development of a local environmental management and risk assessment program
Authors: Wagner Vaughn E. , Bianchi Marco A. , Heeter Carrie
Published: March 2010

An environmental management and risk assessment program (EMRAP) was designed and implemented by the Macomb County Health Department in 1985 to address health problems associated with hazardous materials exposures. The establishment of a toxicological resource center provides a focal point for the rapid assembly, assessment and dissemination of toxicological and biomedical information. The program utilizes a microcomputer with toxicological/biomedical software as well as a telecommunication linkage to public and private databases.

The need for first responder agencies, e.g., fire and police, to effectively manage toxic materials incidents prompted a proposed design modification of the existing EMRAP computer/telecommunication system. The result will be 24-h, 7-d accessibility to biomedical/risk analytical databases by a remote telecommunication information system.
Whole ecosystem manipulation: A productive avenue for test system research?
Authors: Perry James A. , Troelstrup Nels H.
Published: March 2010

Single-species, microcosm and mesocosm toxicity tests frequently have been shown to be inadequate in assessing impacts on whole ecosystems, yet effective environmental management requires attention to such impacts. Whole ecosystem manipulation provides community and ecosystem level assessment, but is expensive and logistically demanding. Thus most whole ecosystem experiments are pseudoreplicated, which gives them limited inferential capability. We present the results of two whole ecosystem experiments — dosing of stream channels with chlorine and ammonia and acidification of a lake — and review several other such experiments from the literature. Most whole ecosystem studies are complex, expensive, involve multiple investigators and have a low degree of true replication. Difficulty in replicating whole system manipulations makes quantifying cause-effect relationships difficult, but this can be partially overcome by carefully developing the inferences from an investigation. In sum, we suggest that such experiments do indeed represent a useful test system, and that they are the only acceptable way of discerning impacts at the community and ecosystem levels.
Flow-through culture techniques for neanthes arenaceodentata (annelida: Polychaeta), including influence of diet on growth and survival
Authors: Pesch Carol E. , Schauer Paul S.
Published: March 2010

Neanthes arenaceodentata has been used frequently in saltwater toxicity tests. A flowing‒water system is described for the laboratory culturing of this polychaete. The system features the shallow, flat trays that are commonly used to culture shellfish. Three diet studies were conducted to determine the best diet to feed laboratory cultures to promote good growth (measured by dry weight) and survival. First, all diets (including commercially prepared diets, yeasts, whole‒grain and grain by‒products, algae, and animal tissue) were evaluated singly in a 28‒d test. Then, selected diets, alone and in combination, were evaluated in two tests (34 and 70 d) that simulated our culture conditions. In the first test, a commercially prepared diet, prawn flakes, produced the best growth; however, worms fed macroalgae had better survival (84% or more versus 60% for those fed prawn flakes). In the last two experiments, a combination of a macroalga and prawn flakes produced the best growth and survival. For example, after 34 d, prawn flakes alone and prawn flakes plus a macroalga produced a similar increase in dry weight of worms (18.8 and 18.7 mg, respectively), but survival was 26% higher with the combination diet.
Concentration dependence of bis(tributyl)tin oxide accumulation in the mussel, mytilus edulis
Authors: Laughlin Roy B. , French Willie
Published: March 2010

Mussels, Mytilus edulis, were exposed in a daily static renewal protocol to five different [l‒14C]bis(tributyl)tin (TBT) concentrations: 23, 45, 63, 141 or 670 ng L‒1. The time course of accumulation in four tissues (gills, viscera, adductor muscle and mantle) was determined for a period of 2 to 7 weeks. The pattern of uptake was strongly concentration‒dependent. In both 23 and 45 ng L‒1 concentrations, an apparent steady state was reached within two weeks. At exposure concentrations of 63 ng L‒1 and above, tissue burdens did not reach a steady state within an observation period of six weeks and increased in proportion to exposure concentration. TBT concentrations in tissues were ranked as follows: gills » viscera > adductor muscle ≈ mantle, with gill concentrations consistently dominating those in other tissues throughout exposure. Bioconcentration factors for TBT in mussels were greater (estimated to be in the range of 1,500 to 7,300) than would be predicted from the Kow value. These studies suggest that M. edulis would be a potentially useful sentinel organism for TBT above a threshold concentration in the marine environment. This threshold appears to be near a value that distinguishes areas receiving direct inputs of antifouling paints from those that do not.
Comparative uptake of hexachlorobenzene by fathead minnows, amphipods and oligochaete worms from water and sediment
Authors: Schuytema Gerald S. , Krawczyk Daniel F. , Grlffis William L. , Nebeker Alan V. , Robideaux Merline L. , Brownawell Bruce J. , Westall John C.
Published: March 2010

Fathead minnows (Pimephales promelas), the worm Lumbriculus variegatus and the amphipod Hyalella azteca were exposed in static tests to hexachlorobenzene (HCB) in water with and without HCB‒spiked sediment to evaluate the relative importance of water and sediment as routes of uptake. The concentration of HCB in water was maintained by passing air saturated with HCB vapor through the test vessels. The presence of HCB‒spiked sediment did not result in a significant increase in bioconcentration factor in two tests with H. azteca. The presence of HCB‒spiked sediment did significantly increase the bioconcentration factor in two tests with fathead minnows and in one of three tests with L. variegatus. The gas phase transfer method was efficient at maintaining a reasonably constant concentration of HCB in water. However, complete control of the aqueous phase activity of HCB through gas phase transfer was not achieved because of the source/sink capacity of the sediment, organisms and food.
Estimation of environmental and toxicological properties: Approach and methodology
Authors: Hall Lowell H. , Kier Lemont B.
Published: March 2010

The estimation of properties of environmental interest is discussed. A general method for estimation based on molecular topology is presented and examples given for several studies. The most widely used topological method is based on the molecular connectivity indexes, which represent molecular structure in numerical form. Other methods presented include shape indexes and an additivity model. The variety of examples discussed and references given indicates the vitality of the use of molecular topology.
Structure-Activity relationships for photooxidation processes in the environment
Authors: Mill Theodore
Published: March 2010

Photooxidation of organic compounds takes place by direct and indirect photoprocesses. Generally, direct photooxidation rate constants cannot be predicted by currently available structure-activity relationships (SARs). Indirect photooxidation processes, in which photogenerated oxidants react with chemicals by electron or H-atom transfer or addition to unsaturated centers, are well understood and rate constants are strongly correlated with structure. This article reviews SARs for predicting rate constants for reactions of HO radical and ozone in the troposphere, and ROn radicals and singlet oxygen in water for reactive organic compounds, and discusses the identification, measurement and reactivity of these oxidants.
Physicochemical properties as predictors of organic chemical effects on soil microbial respiration
Authors: Walton Barbara T. , Anderson Todd A. , Hendricks Marilyn S. , Talmage Sylvia S.
Published: March 2010

Structure-activity analysis was used to evaluate the effects of 19 hazardous organic chemicals on microbial respiration in two slightly acidic soils (a Captina silt loam from Roane County Tennessee, and a McLaurin sandy loam from Stone County, Mississippi), both low in organic car bon and typical of the southeastern United States. Single additions of individual chemicals were applied at 1,000 μg/g (dry weight) soil, which was moistened to 80% base saturation and incubated in the dark at 20°C. CO2 efflux from the soils was monitored at 24-h intervals over a 6-d period The chemicals included in the study were the following: acrylonitrile, furan, methyl ethyl ketone tetrahydrofuran, benzene, toluene, 1,2-dichloroethane, p-xylene, chlorobenzene, chloroform nitrobenzene, trans-1,4-dichloro-2-butene, cis-1,4-dichloro-2-butene, 1,2-dichlorobenzene, 1,2,3 trichloropropane, carbon tetrachloride, 1,2-dibromoethane (ethylene dibromide), 1,2,4,5 tetrachlorobenzene and hexachlorobenzene.

Seventeen of the chemicals caused temporary depressions in CO2 efflux in at least one soil, bu treatments were not significantly different from controls by the sixth day for most of these com pounds, indicating the ability of the microbial community to recover from chemically induced toxicity at this concentration. Acrylonitrile, nitrobenzene, and the 1,4-dichloro-2-butenes causec sustained depressions, whereas methyl ethyl ketone and benzene increased respiration.

The octanol/water partition coefficient (KOW) and molecular connectivity (1x) gave good correlations with effects on soil respiration for a subset of benzene and the six alkyl- and chloro substituted derivatives (i.e., toluene, p-xylene, chlorobenzene, 1,2-dichlorobenzene, 1,2,4,5-tetra chlorobenzene and hexachlorobenzene).
Adaptation of aquifer microbial communities to the biodegradation of xenobiotic compounds: Influence of substrate concentration and preexposure
Authors: Aelion C. Marjorie , Dobbins Durell C. , Pfaender Frederic K.
Published: March 2010

Studies were conducted to examine the adaptation response of aquifer microbial communities to xenobiotic compounds and the influence of chemical preexposure in the laboratory and in situ on adaptation. Adaptation and biodegradation were assessed as mineralization and cellular incorporation of 14C-radiolabeled substrates. For some compounds, such as ethylene dibromide, aniline and m-nitrophenol, biodegradation and adaptation rates were not influenced by chemical concentration over the range tested. Biodegradation rates increased with concentration for p-chlorophenol, and a gradient of adaptation and biodegradation responses was observed for p-nitrophenol up to a threshold concentration. Acclimation to laboratory conditions decreased but did not eliminate the adaptation period to p-nitrophenol. Laboratory adaptation studies and examination of uncontaminated and contaminated field samples from a single aquifer indicated that adaptation was accompanied by shifts in the metabolic fate of the substrate. The increased metabolism associated with adapted communities was predominantly the result of increased mineralization. Cellular incorporation represented a significantly smaller fraction of total metabolism in the adapted versus the unadapted communities. The results indicate that the adaptation response in aquifer solids is due to a complex set of interactions that are influenced by the physiology and growth of the degrading populations.