bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of krenite® brush control agent (fosamine ammonium) on embryonic development in mallards and bobwhite
Authors: Hoffman David J.
Published: March 2010

Fosamine ammonium (Krenite®) is a highly water-soluble carbamoylphosphonate herbicide used to control woody brush. It has been reported to be teratogenic to avian embryos following spray application of the eggs. The embryotoxic and teratogenic potential of Krenite was examined in mallards (Anas platyrhynchos) and bobwhite (Colinus virginianus). At 96 h of development, eggs were briefly immersed in distilled water or in Krenite formulation in distilled water at concentrations of 1.5, 6.5, or 30% fosamine ammonium. At 6.5% active ingredient (a.i.), Krenite reduced hatching success in bobwhite and mallards to 85 and 33% of that in the distilled-water controls. At 30% a.i., Krenite caused 95 to 100% mortality in both species by the time of hatching. Early embryonic growth was impaired by 30% Krenite in both species. There was no evidence of teratogenesis of the axial skeleton, as reported previously in chickens and Japanese quail (Coturnix japonica). Most abnormal embryos had severe edema and some stunting. Mallard hatchlings from the 1.5 and 6.5% Krenite groups weighed significantly less than controls and had lower plasma alanine aminotransferase and aspartate aminotransferase activities, with elevated plasma glucose and cholesterol concentrations. Brain acetylcholinesterase activity was unaffected by Krenite in embryos and hatchlings.
Preparation of aqueous solutions of sparingly soluble organic substances: I. Single component systems
Authors: Billington James W. , Huang Guo-Lan , Szeto Foon , Shiu Wan Ying , Mackay Donald
Published: March 2010

The mass transfer theory underlying the dissolution of sparingly soluble hydrophobic organic chemicals in water is reviewed. It is shown that the preferred method of preparing saturated solutions of such chemicals for physical-chemical or bioassay purposes is by use of the generator column technique, in which water flows through a length of high-surface-area packing coated with the test chemical. The use of shake-flask or batch contacting systems is shown to have inherent disadvantages. A method of calculating the approach to saturation is presented. Solubility data are reported for 13 polycyclic aromatic hydrocarbons, three of which have not been previously reported, and for 10 polychlorinated biphenyl congeners.
Avoidance of brass powder-contaminated soil by the earthworm, lumbricus terrestris
Authors: Wentsel Randall S. , Guelta Mark A.
Published: March 2010

Tests of the avoidance of brass powder (70% Cu, 30% Zn) contaminated soils by the earthworm Lumbricus terrestris at concentrations ranging from 0 to 200 μg/g were conducted. Avoidance was significant (p < 0.001) at brass concentrations as low as 38 μg/g. Avoidance was found to be a more sensitive indicator of the impact of brass powder on the worms than sublethal effects measured by weight loss.
Reactivity of the carbonate radical with aniline derivatives
Authors: Larson Richard A. , Zepp Richard G.
Published: March 2010

Carbonate radicals generated by the photolysis of H2O2 at 313 nm in aqueous sodium bicarbonate (pH 8.3) or carbonate (pH 11.6) solution reacted with substituted aromatic amine derivatives. Particularly fast reactions (second-order rate constants of 5 × 108 to 2 × 109) were observed with anilines bearing electron-donating substituents, either on the ring or at the nitrogen atom. The results suggest that carbonate radicals may play a significant role in the removal of some aromatic amines from the aquatic environment, particularly in carbonate-rich waters.
Effects of acute exposure to acidified water on the behavioral response of fathead minnows, Pimephales promelas, to alarm substance (schreckstoff)
Authors: Smith R. J. F. , Lawrence B. J.
Published: March 2010

Fathead minnows, Pimephales promelas, exposed to acidified water (pH = 5.0) for 72 h continued to respond normally to the alarm substance (Schreckstoff) contained in water extracts of conspecific skin. This result contrasts with an earlier finding that some behavioral responses to chemical feeding stimuli are lost at relatively high pH levels (pH = 6.0). In combination, the two sets of results indicate that different stimulus/response systems have different thresholds for interference by acidification.
Procedure for evaluating the potential ability of birds to avoid chemically contaminated food
Authors: Bennett Richard S. , Schafer Daniel W.
Published: March 2010

A procedure for evaluating the potential ability of birds to avoid chemically contaminated food is described. The discrimination threshold is defined as the dietary concentration above which test animals will decrease the proportion of treated food they consume if untreated alternative foods are available. Two-phase regression analysis is used to calculate the discrimination threshold, 95% confidence interval and the goodness of fit of the model. An index to evaluate the relative potentials for food avoidance behavior between chemicals is described.
Avian response to a turf application of triumph® 4E
Authors: Brewer Larry W. , Driver Crystal J. , Kendall Ronald J. , Lacher Thomas E. , Galindo Janine C. , Dickson Gary W.
Published: March 2010

A field study was conducted to assess the hazard presented by Triumph® 4E insecticide applied to turf at 5 kg a.i./ha to free-ranging birds during the breeding season. The occurrence, distribution, activity and habitat use of birds were monitored on treated and untreated portions of a golf course before and after chemical application. In addition, avian mortality and nesting success were recorded. Residues of Triumph 4E were measured in water, turf and invertebrate samples. Six bird species were more frequently observed following application. Triumph 4E-contaminated mole crickets (Scapteriscus vicinus) (mean, 0.32 ppm, a.i.) that surfaced after treatments were a food source for the birds. At least three of the six species whose numbers increased on the treated field (common grackle, Quiscalus quiscula: boat-tailed grackle, Quiscalus major; and northern mockingbird, Mimus polyglottus) appeared to be attracted to dead or impaired mole crickets. No increases in bird mortality or other adverse effects in reproductive performance were evident.
Sorption of cationic oligomers on sediments
Authors: Podoll R. Thomas , Irwin Katherine C.
Published: March 2010

The adsorption and desorption of oligomers of cationic poly(ethylenimine) (PEI) a poly(N,N-dimethylaminoethyl methacrylate) (PDAM) were measured on several sediments. The adsorption isotherms have a Langmuir shape, with high initial slopes for PEI and adsorption capacities of up to 13% oligomer adsorbed by weight for PDAM. Sorption capacity correlates with the cation exchange capacity for both oligomers. Sorption capacity increases with PEI molecular weight but is independent of PDAM molecular weight. Adsorption/desorption reversibility is less than 15% at all surface coverages for PDAM and for PEI at low surface coverage, but increases up to 50% for PEI at high surface coverage. These data indicate that PDAM adsorbs with all protonated nitrogens directly attached to cation exchange sites at all surface coverages. In contrast, PEI appears to adsorb with a significant mass of adsorbed material in loops and tails indirectly attached to the surface. Adsorption of PDAM appears to increase dramatically if the sediment pH is basic enough to allow bilayer adsorption in the interlamellar region of the sediment. Preadsorption of PDAM on a sediment significantly increased the adsorption of naphthalene from water, suggesting that the lipophilicity of sediments or soils can be substantially increased by oligomer adsorption.
Estimation of gas-phase hydroxyl radical rate constants for organic chemicals
Authors: Atkinson Roger
Published: March 2010

A structure—activity relationship developed for the estimation of rate constants for the gas-phase reactions of the hydroxyl radical with organic compounds is described and extended to certain organophosphorus compounds. The use of this estimation method is illustrated.
“Volume fraction” correlation for narcosis in aquatic organisms: The key role of partitioning
Authors: Abernethyand S. G. , MacKay D. , McCarty L. S.
Published: March 2010

A correlation approach was developed to describe narcosis in several aquatic species. By assuming that narcosis occurs as a result of a constant volume fraction of toxicant at the target site in the test organism, it is possible to correlate LC50s for a series of chemicals with their octanol-water partition coefficients and molar volumes. The approach was successfully tested on acute and chronic toxicity data from the published literature. Two hundred-fourteen toxicity determinations, with 113 different organic chemicals and involving fathead minnow (Pimephales promelas), guppy (Poecilia reticulata), golden orfe (Leuciscus idus melanotus), water flea (Daphnia magna), brine shrimp (Anemia spp.) and Paramecium (Tetrahymena elliotti), were employed.

The data analysis suggests that partition coefficients of the chemicals between the target phase, i.e., the site of toxicant action, in the test organism and water are similar to, but generally lower than, octanol-water partition coefficients. The analysis also suggests a method of correlating the toxicities of mixtures and provides an explanation of the “toxicity cut-off” frequently observed in toxicity tests with chemicals of low water solubility. The interpretation provides insights into the role of partitioning in the acute and chronic effects of nonselective narcotic toxicants.
Modeling bioconcentration of nonpolar organic pollutants by fish
Authors: Barber M. Craig , Suérez Luis A. , Lassiter Ray R.
Published: March 2010

A model describing thermodynamically driven kinetic exchange of organic chemicals between fish and the aqueous environment is developed. This model considers both the biological attributes of the fish and the physicochemical properties of the chemical that determine diffusive exchange across gill membranes. Important biological characteristics addressed by the model are the fish's gill morphometry, body weight and fractional aqueous, lipid and structural organic composition. Relevant physicochemical properties are the chemical's aqueous diffusivity, molar volume and n-octanol/water partition coefficient (Kow), which is used as a surrogate to quantify chemical partitioning to the fish's lipid and structural organic fractions. Using this model, excretion rates, gill uptake efficiencies and bioconcentration factors can be predicted for nonmetabolized organic chemicals.
Database assessment of phytotoxicity data published on terrestrial vascular plants
Authors: Fletcher John S. , Johnson Forrest L. , McFarlane James C.
Published: March 2010

The PHYTOTOX database was analyzed to determine the taxonomic and geographical scope of information published on the toxicity of organic chemicals to terrestrial vascular plants. The data tabulated show the 20 most frequently tested chemicals, the 35 most often used plant genera and species, and the frequency of toxicity testing conducted on plants maintained under different growth conditions (greenhouse, cultivated field, wild, etc.). This information is discussed with regard to its applicability to environmental issues of concern. Examination of the data indicated that the influence of toxic waste compounds on plants is virtually unknown and that little research attention has been focused on the influence of chemical insult on the growth and development of wild plants.
The importance of surface adsorption and pH in metal accumulation by chironomids
Authors: Krantzberg Gail , Stokes Pamela M.
Published: March 2010

Metal body burdens of larval and adult chironomids varied nonlinearly with H+. Metal loss during emergence was an indicator of metal adsorption to the exoskeleton. This adsorbed portion was lower for chironomids collected from lakes of pH 4.4 or 6.1 than for those from lakes of pH 5.1 to 5.5. Pb accumulation was inversely proportional to pH, but Cd, Al, Cu and Ni body burdens were lower at pH 4.4 than at pH greater than 5.1. Short-term larval transplant experiments supported the field observations that surface adsorption can be an important component of the total metal burden of larval chironomids and that adsorption processes may be suppressed at low pH. Changes in metal content in live and dead chironomids exposed to different sediment types were not significantly different. Larvae from a lake of pH 4.4 showed an initial rapid phase of accumulation of Cd, Al, Mn, Ni, Zn and Cu when transplanted to sediments from a lake of pH 5.1. Laboratory and field data supported the hypothesis that surface adsorption contributes to total metal content in chironomids and is responsive to lake pH.
Photooxidation products of smoke generator fuel (SGF) no. 2 fog oil and toxicity to Hyallela azteca
Authors: Poston Ted M. , Bean Roger M. , Kalkwarf Donald R. , Thomas Berta L. , Clark Mark L. , Killand Bruce W.
Published: March 2010

Photooxidation of smoke generator fuel (SGF) No. 2 fog oil was investigated to determine qualitative changes in the chemistry of the oil and the resulting acute toxicity to the freshwater amphipod Hyallela azteca. The 48-h LC50 was about 11.5 mg total oil/L for photooxidized fog oil. Toxicity was related to the greater solubility of photooxidized fog oil in that higher concentrations of total dissolved oil in oil-water mixtures were obtained after equivalent additions of photooxidized oil and nonphotooxidized oil. Photooxidation caused increases in carbonyl oxygen and the presence of alpha- and beta-unsaturated ketones and acetophenones in aqueous extracts. There was no evidence for the formation of phenolic compounds in the photooxidized fog oil or in oil-water mixtures.
Concurrent mobile on-site and In Situ striped bass contaminant and water quality studies in the choptank river and upper chesapeake bay
Authors: Hall Lenwood W. , Bushong Steven J. , Ziegenfuss Michael C. , Hall W. Scott , Herman Roger L.
Published: March 2010

In situ and mobile on-site striped bass prolarval and yearling survival studies were conducted in the Choptank River and in the Chesapeake and Delaware (C & D) Canal area of the Upper Chesapeake Bay. Extensive chemical analyses of both organic and inorganic contaminants in the habitat water were performed and water quality parameters were monitored during these experiments. Surviving yearling striped bass were subjected to histological examination.

Prolarval survival data from both the in situ and mobile on-site studies were similar for each spawning area. Prolarval survival ranged from 30 to 45% after 96 h of exposure to Choptank River water in four separate experiments (two in situ, two on-site); control survival was greater than 74%. Based on a comparison of laboratory toxicity data and reported field concentrations in the Choptank River for various water quality and contaminant conditions, the following combination of conditions was potentially stressful to striped bass prolarvae: low hardness (36 to 48 mg/L CaCO3), monomeric aluminum (0.150 mg/L), cadmium (0.003 mg/L) and copper (0.040 mg/L). Yearling survival in both in situ and on-site tests ranged from 93 to 100% in both the control and Choptank River water after 9 d of exposure. Survival of striped bass prolarvae in C & D Canal water ranged from 52.5 to 70% after 96 h of exposure in four separate experiments. Control survival of prolarvae was not significantly different. Survival of yearling striped bass in on-site and in situ tests was 95% or greater in C & D Canal water and control water. Acute contaminant effects were not verified in the C & D Canal area.
Influence of the method of fluoride administration on toxicity and fluoride concentrations in japanese quail
Authors: Fleming W. James , Schuler Carol A.
Published: March 2010

Young Japanese quail (Coturnix japonica) were administered NaF for 16 d either in their diet or by esophageal intubation. Based on the total fluoride ion (Σmg F−) intake over the 16-d experimental period, fluoride administered by intubation was at least six times more toxic than that fed in the diet. Dietary concentrations of 1,000 ppm F− (Σmg F− for 16 d = approx. 144) produced no mortality, whereas intubated doses produced 73% or greater mortality in all groups administered 54 mg F−/kg/d or more (Σmg F− for 16 d ≥ approx. 23 mg). Graphic comparison of the regression of log F− ppm in femurs/mg F− intake showed that fluoride levels in the femurs of quail administered fluoride by intubation were higher than in those administered fluoride in the diet.
Acute toxicity of chlorophenols to green algae, Selenastrum capricornutum and Chlorella vulgaris, and quantitative structure-activity relationships
Authors: Shigeoka Tadayoshi , Sato Yasuo , Takeda Yuko , Yoshida Kikuo , Yamauchi Fumio
Published: March 2010

The growth inhibition (96-h EC50) of two species of green algae, Selenastrum capricornutum and Chlorella vulgaris, caused by phenol and 12 chlorophenols (from mono-Cl to penta-Cl) was determined according to the Organization for Economic Cooperation and Development guidelines for testing chemicals. The responses of the algae to the chemicals were measured by cell counting, and 96-h EC50 values were correlated with six physicochemical parameters of chlorophenols. The parameters employed in the quantitative structure-activity relationship (QSAR) analyses were n-octanol/water partition coefficient (log Pow), dissociation constant (pKa), Hammett Σσ constant, index of valence molecular connectivity (1χv), perimeter of the efficient cross section of molecule (ΣD) and melting point (F). In the S. capricornutum assay, the toxicity increased as the number of substituted chlorine atoms increased. In the C. vulgaris assay, although toxicity increased from phenol to dichlorophenol, the toxicities of di-, tri-, tetra- and pentachlorophenol were almost the same. QSAR study shows that log Pow gives the best correlation, even in the C. vulgaris assay, by the use of the square of log Pow. Therefore, the growth inhibition of these algae caused by chlorophenols is mostly influenced by lipophilicity, as is stated frequently in toxicity studies using aquatic animals.
Regional variation of indoor radon over three seasons
Authors: Mushrush George W. , Mose Douglas G.
Published: March 2010

The levels of 222Rn in homes located in Fairfax County, Virginia, and Montgomery County, Maryland were measured using alpha-track detectors during three consecutive 3-month seasonal intervals. Indoor radon can be related to the geological material under homes and to home construction. The indoor radon levels during winter were about twice as high as anticipated. Approximately 50% of the homes had winter indoor radon levels above 4 pCi/L, the U.S. Environmental Protection Agency's recommended “action” level. During spring, indoor radon levels showed a considerable drop, with approximately 35% of the homes above 4 pCi/L. Values in summer were even lower, with approximately 22% of the homes above 4 pCi/L.
Inhibition and stimulation of trichloroethylene biodegradation in microaerophilic microcosms
Authors: Barrio-Lage Gladys A. , Parsons Frances Z. , Lorenzo Pedro A.
Published: March 2010

The possibility of increasing the biotransformation rate of trichloroethylene (TCE) in ground water and subsurface environments by nutrient addition to microcosms was studied. Three sets of microcosms made of sediment and water were prepared under a nitrogen atmosphere to preserve microacrophilic conditions; each set contained one of the following nutrients: sulfate, methane or ethylene. A control set of microcosms without nutrients was also prepared. The addition of methane was found to increase the biotransformation rate of TCE, allowing the depletion of 99.6% of the TCE in 6 months of incubation, with a lag time of 3 months. In the control microcosms, with no added nutrient, 78% of the TCE was depleted in 6 months of incubation. However, in the microcosms to which sulfate or ethylene was added, the half-life of TCE was appreciably increased. This indicates that methane addition increased the ability of the indigenous microorganisms to biodegrade TCE under microaerophilic conditions, and that sulfate addition inhibited the organisms responsible for the biotransformation of TCE or their biodegrading ability. The effect of ethylene was ambiguous; bacterial growth did not occur in sediment-water cultures supplied with ethylene as the sole carbon source. Hence ethylene either inhibited growth of indigenous bacteria or was not a suitable carbon source. The microcosm experiments suggest that biotransformation resulted from the action of methylotrophs, coexisting in microhabitats with methanogens, which cometabolize the chlorinated ethenes with methane.
Investigation of carbofuran and its metabolites by gas-liquid chromatography in green and dry hops
Authors: Archer T. E. , Chu Y. Y. , Engebretson J. A.
Published: March 2010

Processed hop cones (Humulus americanus) are an important flavoring component in beer, and it is possible that carbofuran and its metabolites could be found in treated hops and thus in beer. Hop cones were treated with 1.12 kg/ha active ingredient carbofuran (2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl-N-methyl carbamate) for the control of root weevils (Otiorhynchus sulcatus, O. ovatus). The carbamates in the cones were determined using gas-liquid chromatography (GLC) and a thermionic specific detector. The percent recoveries for the carbamates ranged from 88.7 ± 5.3 to 95.3 ± 6.3% (green hops) and from 88.6 ± 12.3 to 98.0 ± 5.0% (dry hops). The phenolic metabolites were analyzed as their 2, 4-dinitrophenol ether derivatives, using GLC with an electron capture detector. The percent recoveries ranged from 85.0 ± 5.8 to 88.3 ± 8.5% (green hops) and from 80.3 ± 4.4 to 95.3 ± 3.0% (dry hops). The GLC procedure was sensitive to 0.05 ppm. Control samples in all cases contained less than 0.05 ppm and green, treated hop cones had residues of less than 0.05 ppm. Dry treated hop cones contained less than 0.05 ppm of all chemicals, except 3-keto-7-phenol (0.12 ppm) and the 3,7-diol (0.07 ppm). Although the U.S. Environmental Protection Agency (EPA) has not established tolerance levels for carbofuran and its metabolites in hop cones, the present investigation shows that residue levels on green and dry hop cones are well below the EPA's tolerances for carbofuran in other commodities.
Minutocellus polymorphus: A new marine diatom for use in algal toxicity tests
Authors: Walsh Gerald E. , McLaughlin Leslie L. , Yoder Mark J. , Moody Paul H. , Lores Emile M. , Forester Jerrold , Wessinger-Duvall Paul B.
Published: March 2010

The marine diatom Minutocellus polymorphus is suited for use as a test species in algal toxicity tests. Its responses to 19 toxicants in a modification of Aquil, a chemically defined phytoplankton culture medium, compared favorably with those of Skeletonema costatum, a common test species. M. polymorphus grows rapidly, allowing a test duration of 48 h and thus minimizing complications due to toxicant degradation, volatilization and adsorption to test vessel walls. These and other characteristics indicate that M. polymorphus is an ideal standard organism for algal toxicity tests.
Techniques for the laboratory culture of mysidopsis species (crustacea: Mysidacea)
Authors: Lussier Suzanne M. , Kuhn Anne , Chammas Melissa J. , Sewall John
Published: March 2010

The objectives of this study were to evaluate existing techniques for culturing three species of the genus Mysidopsis that are routinely used as toxicity test organisms. A comparison of the life history, ecology and distribution of M. bahia, M. bigelowi and M. almyra is presented. Culture systems are described, supplemental foods are suggested, and guidelines are given for salinity, temperature, dissolved oxygen and nitrogen levels that will maintain optimum laboratory culture conditions. Methods are outlined for harvesting juveniles and controlling contaminant organisms, and general feeding procedures are described. Culture management is stressed as the most significant factor in maintaining productive mysid cultures. Specific recommendations are made regarding culture density, harvesting frequency, sex ratio and introduction of feral animals.
Techniques for the culture of ghost shrimp (palaemonetes pugio)
Authors: Poole Bruce M.
Published: March 2010

The ghost shrimp, Palaemonetes pugio, is a common estuarine member of the food chain. It is widely used in bioassay testing by the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency. Culture techniques for the ghost shrimp have been established for more than 10 years. The organism, as an adult, is vivacious and will breed readily in captivity. The larvae have a 30‒d life cycle in which they consume a variety of planktonic organisms before assuming the adult form. The ghost shrimp is utilized in testing metallic, organic and petroleum contaminants in the marine and estuarine environments, both in the larval stages (aged 2–4 weeks) and in the adult stage.
Laboratory culture of gametophytic stages of the marine macroalgae champia parvula (rhodophyta) and laminaria saccharina (phaeophyta)
Authors: Steele Richard L. , Thursby Glen B.
Published: March 2010

Methods to help characterize the toxicity of effluent discharges within the National Pollutant Discharge Elimination System have been developed for the marine red alga Champia parvula and are currently being developed for the brown alga Laminaria saccharina. These methods require maintaining male and female gametophytes in laboratory cultures. Aseptic techniques are recommended even though the cultures are not intended to be axenic; the purpose is to guard against microalgal contamination. C. parvula can be grown at room temperature, but L. saccharina requires a controlled temperature chamber (12–15°C). Both species can be cultured successfully in either natural or artificial seawater.
Evaluation of the xenon arc lamp as a light source for aquatic photodegradation studies: Comparison with natural sunlight
Authors: Yager Judith Evans , Yue Chifoo David
Published: March 2010

The use of xenon arc illumination as a substitute for natural sunlight in the aqueous photolysis test was evaluated by exposing four chemicals to both xenon arc and sun illumination. The chemicals were chosen based on their known photodegradation half‒lives, absorption maxima and ease of analysis. The percentage of chemical remaining at the end of the exposure period and the photodegradation half‒life were compared for each chemical by light source. To compensate for the variability in natural sunlight intensity during an exposure period, data were also compared based on total light exposure, i.e., the intensity of exposure integrated over time. Photolysis of the four chemicals under the xenon arc lamp compared favorably with that under sunlight. Based on the results of this study, xenon arc illumination is equivalent to sunlight for use in determining aqueous photolysis rates.
Effects of mixtures of sediment contaminants on the marine infaunal amphipod, rhepoxynius abronius
Authors: Swartz R. C. , Kemp P. F. , Schults D. W. , Lamberson J. O.
Published: March 2010

The infaunal amphipod, Rhepoxynius abronius Barnard, was exposed to mixtures of sediment contaminants at concentrations of the individual compounds that produce few or no effects. Combinations of zinc, mercury, polychlorinated biphenyls (Aroclor® 1254) and fluoranthene produced joint toxicological actions that could be classified as additive or less than additive. To be more ecologically relevant, sediment quality criteria should be expressed in relation to a model of interactive effects. A relatively small decrease in the total volatile solids content of sediment from 1.72 to 1.30% increased the concentration of contaminants in interstitial water and increased sediment toxicity.
Use of the amphipod crustaceanhyalella aztecain freshwater and estuarine sediment toxicity tests
Authors: Nebeker Alan V. , Miller Clifford E.
Published: March 2010

Hyalella azteca (Saussure), which are currently used in toxicity tests with freshwater sediments, were tested to determine their suitability for tests with estuarine sediments. Reproduction was good after 24 d at and below 12.5 g/L (ppt) salinity in water only. EC50 values (50% reduction in young) were 10.5 and 10.4 g/L salinity. Survival was good in tests conducted with estuarine sediments collected from a range of freshwater to full seawater sites, using fresh water overlaying the sediments (200 ml sediment, 800 ml water). The results demonstrate that H. azteca can be used to test the toxicity of sediments from both freshwater and estuarine sites.
Structure-Activity relationships in environmental toxicology and chemistry: Narcosis, electrophile and proelectrophile toxicity mechanisms: Application of SAR and QSAR
Authors: Lipnick Robert L.
Published: March 2010

A historic account is provided of the development of quantitative structure‒activity relationships (QSARs) for the toxicity of simple nonelectrolyte organic compounds. The aquatic toxicity of many such compounds has been shown to be consistent with a narcosis mechanism involving pseudo‒steady‒state partitioning into a lipoidlike biophase site of action. These data are well fitted to a linear QSAR model involving solely the log P parameter.

The toxicity of such nonelectrolytes administered by inhalation yields a linear QSAR based on the oil/gas partition coefficient. In contrast, the toxicity of these substances produced by nonequilibrium routes of administration, such as rat oral LD50, yields a parabolic or bilinear relationship consistent with observations published by Cros in France in 1863. Electrophile toxicants capable of forming covalent adducts with biochemical target molecules are more toxic than predicted by the corresponding narcosis models. Proelectrophile toxicants, which require metabolic activation to electrophiles, are also more toxic than would be predicted by narcosis QSARs.
Competitive binding of chlorinated azobenzenes to the Ah receptor protein
Authors: Bunce Nigel J. , M. Choong Douglas K. , Landers James P. , Zacharewski Tim R.
Published: March 2010

Substituted azobenzenes bind to the aryl hydrocarbon receptor protein about one to two orders of magnitude less strongly than does 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) when they carry substituents at some of the positions 2, 3, and 4 of the benzene rings. Positions 5 and 6 are disfavored. The results are interpreted in terms of the stability of azobenzene conformers and the extent to which the azobenzenes under study are isosteric with TCDD.
Structure-Activity for uptake and toxicity of DDT-type insecticides utilizing an NMR method for estimating σ*
Authors: Coats Joel R. , Williams John W. , Chang Carolyn , Lee An-Horng , Metcalf Robert L.
Published: March 2010

Structure-activity relationships were examined in toxicological studies with DDT-type insecticides. The Taft σ* parameter for the electronegative character of substituents correlated well with the uptake of the analogs through insect tarsi and with acute oral toxicities to mice. Substituent groups with stronger electron-withdrawing capacities penetrated more slowly through the insect cuticle and were markedly more toxic to mice. A nuclear magnetic resonance method was utilized to obtain estimated σ* values for use in the correlations.
Microbial degradation kinetics of toxic organic chemicals over a wide range of concentrations in natural aquatic systems
Authors: Hwang Huey-Min , Hodson Robert E. , Lewis David L.
Published: March 2010

The degradation kinetics for several toxic organic compounds (p-cresol, phenol, p- chlorophenol, acetone and methanol) exposed to natural aquatic microbial assemblages were examined over a wide range of concentrations. Compounds were added in radiolabeled form and incubated at 25°C for periods ranging from several hours to one day. The results revealed that degradation kinetics were multiphasic for each of the compounds during at least one sampling period, i.e., the kinetic parameters Kt and Vmax increased with increasing substrate concentration. The observed multiphasicity suggests the presence within the natural microbial assemblages of multiple uptake/degradative systems, each with distinguishable kinetic parameters and each dominating degradation at a different substrate concentration range. If the kinetic diversity is ignored and rates of degradation are calculated based on the assumption that kinetics follow simple hyperbolic (Michaelis-Menten) relationships, then errors as large as 40,000-fold can result. Thus, our results suggest that models for predicting the persistence of such compounds in natural waters should consider changes in kinetic constants with substrate concentration.
Assessing interactions of organic compounds during biodegradation of complex waste mixtures by naturally occurring bacterial assemblages
Authors: Hwang Huey-Min , Hudson Robert E. , Lewis David L.
Published: March 2010

Selected organic chemicals were tested to determine the minimum concentrations at which complete inhibition of microbial degradative processes occurred. Complete inhibition did not occur at less than 2 g/L phenol, 10 g/L toluene or n-butanol and 100 g/L acetone, benzene or methanol. Consequently, microbial degradative processes may play a significant role in the abatement of even very high organic pollutant concentrations. Glucose utilization and thymidine uptake rates were tested as indicators of the toxic effects of the organic pollutants. Both methods accurately indicated the concentrations of organic pollutants required to cause cessation of degradative activities and could serve as indicators of degradative inhibition, in lieu of degradation studies, when analytical processes for test organics are expensive or unavailable. Degradation kinetics of the high organic chemical concentrations followed typical multiphasic kinetic patterns, which tended to yield pseudo-first-order degradation rates over a wide range of chemical concentrations, except when chemical concentrations were sufficiently high to elicit metabolic inhibition.
Acute toxicity of sediment from Eagle Harbor, Washington, to the infaunal amphipod Rhepoxynius abronius
Authors: Swartz Richard C. , Kemp Paul F. , Schults Donald W. , Ditsworth George R. , Ozretich Robert J.
Published: March 2010

Creosote-contaminated sediment from one station (EH08) in Eagle Harbor, Washington, is among the most toxic sediment yet tested from U.S. estuaries and coastal waters. The total concentration of 13 polynuclear aromatic hydrocarbons in EH08 sediment was 6,461 mg/kg (dry wt.). The concentrations of phenanthrene and fluoranthene in this sediment were more than two orders of magnitude greater than their acutely lethal concentrations. In dilution experiments with uncontaminated sediment from Yaquina Bay, Oregon, the 4-d LC50 of EH08 sediment to the amphipod Rhepoxynius abronius (Barnard) was 666 mg/kg (wet wt.). Sediment from other stations within 150 m of EH08 was not acutely toxic to Rhepoxynius, indicating the patchiness of sediment contamination and toxicity in Eagle Harbor.
Kinetic and spectroscopic investigations of the covalent binding of benzidine to quinones
Authors: Ononye Aloysius I. , Graveel John G. , Wolt Jeffrey D.
Published: March 2010

Model studies of the covalent binding of benzidine (4,4′‒diaminobiphenyl), a hazardous biphenyl amine, to humic acid have been carried out through kinetic and spectroscopic investigation of the reaction of benzidine with substituted quinones in aqueous solution. Benzidine reacts with quinones through a single‒phase second‒order mechanism involving addition of the amino group of benzidine to the C=O group of the quinone (imine formation) and the C=C bond in the quinone ring (1,4‒nucleophilic addition), respectively. The products do not show reversibility in water. Reactivity decreases with increase in substitution on the quinone rings. The results provide more understanding of the pathway by which aromatic amines could couple with quinonoid groups present in humic acids.
Effects of contaminants on the frequencies of allozymes in populations of the central stoneroller
Authors: Gillespie Robert B. , Guttman Sheldon I.
Published: March 2010

Allele and genotype frequencies for allozymes of phosphoglucomutase (PGM) differed significantly between populations of the central stoneroller (Campostoma anomalum, Rafinesque) collected from sites above and below impact from industrial activities. The frequencies of the PGM‒A allele and PGM‒AA and PGM‒AB genotypes were significantly less in populations of stoneroller minnows collected from impacted sites than in populations upstream of impact. Stonerollers with these sensitive PGM genotypes and stonerollers with genotypes of malate dehydrogenase MDH‒BB were more sensitive to the toxic effects of copper sulfate than other genotypes under laboratory conditions. These results suggest that individuals with certain allozymes may be more sensitive to the toxic effects of environmental contaminants than those with other genotypes. Selection or elimination of individuals with sensitive genotypes by contaminants may result in a narrowing of genetic diversity in populations and thus increase the susceptibility of these populations to further stress. Electrophoretic determination of genetic structure in fishes appears to be sensitive to changes in water quality and may be a useful tool for monitoring the health of aquatic populations.
Differential survivorship of allozyme genotypes in mosquitofish populations exposed to copper or cadmium
Authors: Chagnon Norman L. , Guttman Sheldon I.
Published: March 2010

Laboratory stocks of mosquitofish (Gambusia affinis) were acutely exposed to copper (0.16–0.24 mg/L) or cadmium (6.7–9.5 mg/L) for 48 h using a static renewal system. Allozyme genotypes at three polymorphic loci: phosphoglucomutase‒2 (PGM‒2), glucose phosphate isomerase‒2 (GPI‒2), and isocitrate dehydrogenase‒2 (ICD‒2) were resolved using a modified starch gel (13%) electrophoretic technique. Differential survivorship of allozyme genotypes was analyzed using a Wilcoxon matched pair signed‒rank test. Copper significantly (p < 0.05) decreased the overall survivorship of fish heterozygous at the GPI‒2 locus. The frequency of the (ab) genotype was significantly higher in the dead fraction of the test populations than in the surviving fraction. The frequencies of the (aa) genotype and the (a) allele at the ICD‒2 locus were significantly higher in female fish surviving exposure to copper than in nonsurviving females. The frequencies of the (bb) genotype and the (b) allele at the GPI‒2 locus were significantly higher in fish surviving exposure to cadmium than in nonsurvivors. These results indicate that some electrophoretically detectable allozymes are more sensitive than others to the toxic effects of environmental pollutants. This suggests that the genetic structure of natural populations should be considered for use as a biological monitor of environmental pollution.
Groundwater ubiquity score: A simple method for assessing pesticide leachability
Authors: Gustafson D. I.
Published: March 2010

Government agencies at both the state and federal levels now face increasing pressures to assess the likelihood of pesticide occurrence in well‒water supplies. Screening methodologies are required in order to determine which pesticides now in use should receive the greatest attention with respect to groundwater, and in order to determine whether elaborate and expensive groundwater testing should be required in order to register a new pesticide. Several screening techniques have been proposed recently, some based on threshold values for critical physical properties of the pesticide, and others based on mathematical models of the leaching process. A different approach is taken in this paper, whereby an index is derived based entirely on the physical properties of those pesticides that have been found either leachable or essentially immobile. The index is based on graphical examination of a plot formed by two widely available pesticide properties: half‒life in soil (tsoil1/2) and partition coefficient between soil organic carbon and water (Koc). Other physical properties, such as water solubility, octanol/water partition coefficient, and volatility from soil, have often been invoked as indicators of leachability, but they are found in this paper to have no useful power in discriminating between “leachers” and “nonleachers.” Scores assigned with the new screening index agree with the results of several recent well‒water monitoring programs, even though point‒source events are thought to be responsible for some of the observed contamination. A nomogram is given that reduces the task of calculating the index to simply placing a straight edge on a diagram.
Toxicity of pyrethroids to marine invertebrates and fish: A literature review and test results with sediment-sorbed chemicals
Authors: Clark James R. , Goodman Larry R. , Borthwick Patrick W. , Patrick James M. , Cripe Geraldine M. , Moody Paul M. , Moore James C. , Lores Emile M.
Published: March 2010

Data on the acute and chronic toxicities of permethrin, fenvalerate, cypermethrin and flucythrinate to marine invertebrates and fish are reviewed. Generally, crustaceans are more sensitive than fish; oysters are comparatively insensitive. The mysid Mysidopsis bahia consistently is among the most sensitive crustaceans tested, with 96—h LC50s of less than 0.02 μg/L for permethrin and of less than 0.01 μg/L for fenvalerate, cypermethrin and flucythrinate. The potential for chronic toxicity to fish is minimal for permethrin, moderate for fenvalerate and relatively great for flucythrinate.

Laboratory toxicity tests were conducted with sediment—source fenvalerate and cypermethrin under static and flow—through conditions to determine the degree of contamination necessary to achieve acute lethal effects on mysids, grass shrimp (Palaemonetes pugio) and pink shrimp (Penaeus duorarum). Mortality was observed in test animals only in systems where the concentrations of sediment—source pyrethroids were sufficient to establish lethal concentrations in the overlying water through sediment/water partitioning. For fenvalerate, lethal effects occurred at nominal sediment concentrations of 0.1 mg/kg (static and flow—through) for mysids and grass shrimp and at 10 mg/kg for pink shrimp. Nominal sediment concentrations of cypermethrin of 0.1 mg/kg (static) or 1.0 mg/kg (flow—through) resulted in mortality in mysids and grass shrimp, whereas 1.0 mg/kg was the only test concentration that caused mortality in pink shrimp in the static and flow—through test systems. The correspondence between aqueous concentrations and LC50s for test animals demonstrated the importance of quantitating the bioavailable portion of pyrethroids in field samples to characterize accurately the environmental risk associated with pyrethroid runoff after agricultural applications.
A comparison and evaluation of field and laboratory toxicity tests with fenvalerate on an estuarine crustacean
Authors: Baughman Douglas S. , Moore David W. , Scott Geoffrey I.
Published: March 2010

Field and laboratory toxicity tests were conducted on the grass shrimp, Palaemonetes pugio, to evaluate the usefulness of laboratory testing in estimating mortality from fenvalerate exposure associated with agricultural runoff. The study examined an integrated approach for assessing the impacts of fenvalerate on estuarine fauna, using 96—h static—renewal and 6—h pulsed—dose laboratory toxicity tests and in situ toxicity tests. The laboratory toxicity tests with fenvalerate gave 96—h LC50 values ranging from 0.007 to 0.071 μg/L and 6—h PDLC50 values ranging from 0.100 to 0.130 μg/L. Comparisons of the results of two field toxicity tests with laboratory—derived LC50 values showed good agreement between field and laboratory toxicity data. The variation between field and laboratory toxicity tests may have been due to the limitations of the water sampling regime used in characterizing the pesticide exposure during the field toxicity tests. These comparisons suggest that a combination of laboratory and field toxicity testing is required to estimate the actual field mortality from fenvalerate exposure associated with agricultural runoff. Future studies should include composite water sampling and more frequent discrete sampling methods to better characterize field exposure regimes.
Structure—activity relationship studies on the toxicity of benzene derivatives: III. Predictions and extension to new substituents
Authors: Hall Lowell H. , Maynard Ellen L. , Kier Lemont B.
Published: March 2010

The additivity model developed earlier for 65 substituted benzenes has been extended to 105 compounds for the fathead minnow system. Toxicity is predicted for 10 compounds not included in the original data set. Four new substituents have been evaluated and their toxicity contributions have been determined by regression analysis. For the whole data set, the following statistics were obtained for the 12—variable model: r=0.921, s=0.31, F=43. The order of toxicity contributions for all substituents now investigated is as follows: —NO2 ≈ —Cl > —Br > —CHO > —CH3 ≈ —F > —NH2 ≈ —CN > —OH ≈ —OCH3 > —COCH3. Also identified in these analyses is the additional toxicity conferred by the ortho—hydroxybenzaldehyde combination. Such a structural arrangement increases toxicity by 1.45 units over both the meta and para arrangements. For the 11 substituents, relationships have been sought between the toxicity contribution and physicochemical parameters, including partition coefficient (π) and electronic parameters, but no significant relation has been found. Also evaluated were five additional substituents for which there are few data. Approximate toxicity contributions are reported for these substituents.
Toxicity of nine benchmark chemicals to Skeletonema Costatum, a marine diatom
Authors: Cowgill U. M. , Milazzo D. P. , Landenberger B. D.
Published: March 2010

The purpose of this study was to determine the sensitivity of a marine diatom to eigm common chemicals and one herbicide. The 50% reduction in the number of cells per milliliter and that of total cell volume × 104 μm3/ml was estimated in relation to each of the nine chemicals. Nominal concentrations of triclopyr triethylamine salt (Garlon 3A), K2Cr2O7, 4—chlorophenol and phenol were slightly toxic (>10 mg/L) according to the U.S. Environmental Protection Agency classificatory scheme, while diethanolamine, chlorobenzene, chloroform, acetone and ethanol were classified as practically nontoxic (>100 mg/L). No observed effect levels were found for each of the two cell measurements in relation to each of the chemicals tested for the 5—d period of the test. The range was found to be from 1 to 6,000 mg/L for total cell count and from 0.65 to 6,000 mg/L for total cell volume. Data on the sensitivities of other organisms to the group of common chemicals are also included. The marine diatom proved to be less sensitive to K2Cr2O7 and diethanolamine than the green alga Selenastrum capricornutum.
Analysis of trifluralin, methyl paraoxon, methyl parathion, fenvalerate and 2,4-D dimethylamine in pond water using solid-phase extraction
Authors: Swineford Douglas M. , Belisle Andre A.
Published: March 2010

A method was developed for the simultaneous extraction of trifluralin, methyl paraoxon, methyl parathion, fenvalerate, and 2,4-D dimethylamine salt in pond water using a solid-phase C18 column. After elution from the C18 column, the eluate was analyzed on a capillary gas Chromatograph equipped with an electron-capture or flame photometric detector.