bluuebunny/crossref_metadata_2025 huggingface dataset:
Fate of 3,3′-dichlorobenzidine in soil: Persistence and binding
Authors: Boyd Stephen A. , Kao Chun Wei , Suflita Joseph M.
Published: March 2010

The fate of the carcinogen 3,3′-dichlorobenzidine (DCB) in soil was evaluated with regard to persistence and binding. A Brookston clay loam soil was amended with 4 or 40 ppm 14C-DCB and incubated under aerobic conditions for 32 weeks or under anaerobic conditions for 1 year. Mineralization occurred very slowly in aerobic soil and did not occur in anaerobic soil. Total 14C radioactivity in soil remained essentially constant during the incubations, demonstrating that volatile losses of DCB or DCB decomposition products did not occur in our incubation system. DCB was shown to bind strongly to soil. After 32 weeks of incubation, approximately 90% of the applied radioactivity remained in soil after extraction with ethyl acetate and methanol. The loss of solvent-extractable DCB occurred mostly in the first several weeks of incubation and was accompanied by an increase in alkali-extractable DCB. These data strongly suggest the formation of covalent linkages between DCB and soil humic components as the primary fate of DCB in the Brookston soil. The significance of humus-bound DCB residues as potential sources of future contamination is essentially unknown.
Photolytic oxidative demethylation of aqueous dimethylsiloxanols
Authors: Buch R. R. , Lane T. H. , Annelin R. B. , Frye C. L.
Published: March 2010

Dimethylsilanediol and other water-soluble dimethysiloxanols undergo aqueous photolytic oxidative demethylation with tropospheric ultraviolet radiation in the presence of suitable chromophores, such as nitrogen oxides, to give silicic acid and carbon dioxide. The “biosuitability” of the resulting silicic acid was demonstrated by monitoring the growth of diatoms (Navicula pelliculosa) in the irradiated aqueous media. Thus, a plausible route for the further degradation of such water soluble hydrolysis products of poly(dimethyl-siloxane) to naturally occurring materials was conclusively demonstrated. Furthermore, di- and monomethyl silanol species were shown not to be utilized by the diatom colony, even when present as completely water soluble components.
Transport and fate of diethyl phthalate in aquatic ecosystems
Authors: Lewis David L. , Holm Harvey W. , Kollig Heinz P. , Hall Tom L.
Published: March 2010

Sorption, alkaline hydrolysis, photolysis and microbial transformation of diethyl phthalate (DEP) were studied in a large laboratory aquatic ecosystem composed of a series of reactor tanks. Microbial transformation accounted for 95 to 99% of the rapid loss of DEP from water. First-order rate coefficients for the loss of DEP, except in reactor tanks depleted of inorganic nutrients, were statistically constant among diverse chemical and microbial environments, suggesting a constant transformation rate per unit of colonized surface area. The diversities of reactor tank environments were substantiated by large ranges in the dissolved organic carbon, nitrogen, phosphorus, chlorophyll, ATP and biomass measurements. Microbial transformation of DEP resulted specifically from bacterial activity, most of which was associated with aquatic microbial growth (aufwuchs) attached to submerged surfaces or suspended in streamers or mats.
Time variable model of the fate of DDE and lindane in a quarry
Authors: Di Toro Dominic M. , Paquin Paul R.
Published: March 2010

A time variable model has been used to analyze a field scale experiment in which a flooded limestone quarry was dosed with equal quantities of Lindane and DDE. The water column and sediment chemical concentrations were monitored for one year after the initial dosing. The markedly different physical-chemical characteristics of the test chemicals provided an interesting contrast for model application.

A simplified time variable model of partitioning chemicals is cast in the form of analytical solutions for the total, dissolved and particulate concentrations of chemical in completely mixed, interactive, water column and sediment compartments. The model formulation incorporates chemical decay and transport mechanisms of particulate and diffusive exchange between water column and sediment. The Lindane and DDE model calibrations based on data from the first year after dosing are presented. A preliminary verification of the model, obtained by projecting DDE levels in the water and sediment five years after initial dosing, when the quarry was revisited, is also shown. The model results underscore the significance of chemical partitioning on chemical fate and highlight the importance and utility of a modeling framework which incorporates realistic mechanisms of water column and sediment interaction.
A seven-day life cycle cladoceran toxicity test
Authors: Mount D. I. , Norberg T. J.
Published: March 2010

A three-brood life cycle test for Ceriodaphnia reticulata, using renewal techniques, that can be completed in 7 d is described. The test is convenient when samples to be tested are limited in volume or when time is especially important, such as in on-site effluent testing. The cladoceran C. reticulata is easily cultured and is not bothered by handling; control survival in tests has not been a problem.
Comparison of physical and chemical characteristics of shale oil fuels and analogous petroleum products
Authors: Ghassemi Masood , Panahloo Arshia , Quinlivan Sandra
Published: March 2010

The available data on the physical and chemical characteristics of crude and hydrotreated shale oil and for shale-derived naphtha, jet fuel, diesel fuel and residual fuel are reviewed and compared with similar data for analogous petroleum products. The databases for shale oil and petroleum are very diverse and have been generated by numerous investigators using a range of analytical procedures and test samples of various origins, including different raw material sources, processing scales and operating conditions. For both petroleum and shale oil, the detailed compositional data primarily relate to lighter “cuts.” Similar data for heavier cuts generally have not been obtained because of the very complex and variable nature of these products and the questionable utility of the results from the standpoint of refinery applications, and because properties of the individual compounds (especially from the standpoint of biological activity) may not be directly additive. Based on the data reviewed and the consideration of raw material chemistry and nature of the refining operation, it appears that the differences between shale oil and petroleum products are generally a matter of degree rather than kind, with the degree of similarity increasing with the extent of refining.
Non-invasive electrophysiological monitoring: A sensitive method for detecting sublethal neurotoxicity in earthworms
Authors: Drewes Charles D. , Vining Elizabeth P. , Callahan Clarence A.
Published: March 2010

Earthworms were exposed, by external surface contact, to three chemical pollutants: dieldrin (a known neurotoxicant), dimethyl phthalate and fluorene (a possible neurotoxicant). After 48 h of exposure, LC50 values were determined and compared with concentrations required for sublethal neurotoxic effects on giant nerve fiber conduction velocity and escape reflex function, as assessed by nonin vasive electrophysiological recordings. For dieldrin, sublethal decreases in giant fiber conduction velocity occurred at concentrations as low as 1.4 ppm, whereas much higher concentrations were required for lethality (48-h LC50 = 8,100 ppm). Other sublethal effects of dieldrin included hyperresponsiveness of giant fibers, reduction in giant fiber-mediated muscle potentials, tonic spasms of longitudinal shortening and ataxia. For fluorene, sublethal neurophysiological effects, including reduced conduction velocity and occasional “rebound” spiking of giant fibers, were evident at 100 and 250 ppm. By comparison, the 48-h LC50 for fluorene was 360 ppm. No sublethal neurophysiological effects were evident following treatment with dimethyl phthalate; the 48-h LC50 was 10,900 ppm. The results indicate that noninvasive electrophysiological recording of earthworm escape reflex function can be used as a sensitive means of detecting potential sublethal neurotoxic effects of pesticides and other environmental pollutants in these nontarget organisms.
Effects of copper, nickel and zinc on the life cycle of the caddisfly Clistoronia magnifica (limnephilidae)
Authors: Nebeker Alan V. , Savonen Carol , Baker Rocky J. , McCrady Joel K.
Published: March 2010

The caddisfly Clistoronia magnifica (Banks) (Limnephilidae) was exposed to copper, nickel and zinc in life cycle tests. The copper test included continuous exposure of first-generation aquatic larvae and pupae, second-generation larvae and pupae and third-generation larvae. The aerial adults and eggs were exposed only to body burdens obtained as larvae and pupae. Nickel and zinc tests included first and second-generation exposure. Copper concentrations of ≥17 μg/L prevented completion of the life cycle, and significant reduction in adult emergence occurred at 13.0 μg/L. The no-observed-effect level for copper was 8.3 μg/L. Nickel concentrations of ≥250 μg/L prevented completion of the life cycle. The no-observed-effect level for nickel was 66 μg/L. At the highest zinc concentration (5,243 μg/L), no effects were observed on any of the life stages.
Mutagenicity of bottom sediment from a water reservoir
Authors: Lower William R. , Yanders Armon F. , Underbrink Alan G. , Drobney V. Kay , Marrero Thomas R. , Collins Michael D.
Published: March 2010

The bottom sediment of an earthen water reservoir was found to cause elevated somatic mutation frequencies in the stamen hair system of Tradescantia and a decrease in the transient chlorophyll fluorescence yield in leaves of Tradescantia and Zea mays. The mutation frequencies varied only slightly over time, and remained elevated for 91 d of chronic treatment when compared with controls. Chemodynamic modeling indicates that chemicals, including mutagens, can be transferred effectively from reservoir bottom sediment to water.
Transformation of Bacillus subtilis with DNA-encoding naphthalene degradation from Bacillus megaterium
Authors: Oh S. Y. , Quensen J. , Matsumura F. , Momose H.
Published: March 2010

The ability to degrade [14C]-naphthalene was transferred from Bacillus megaterium to B. subtilis by extracting B. megaterium DNA and introducing it into B. subtilis using the protoplast-polyethylene glycol method. Naphthalene degradation was indicated by the accumulation of water soluble 14C activity and the presence of a unique solvent-extractable metabolite on TLC analysis. In addition, resistance to dibenzofuran, p-chlorobiphenyl, and naphthalene (as demonstrated by lack of growth inhibition by these compounds) was transferred by the same technique. B. megaterium ATCC 13368 and derivatives conditioned to the presence of each of these three chemicals were used as DNA donors. B. subtilis transformants showed greater resistance to the chemical to which the DNA donor B. megaterium had been conditioned.
Bioconcentration of cypermethrin, deltamethrin, fenvalerate and permethrin by Chironomus tentans larvae in sediment and water
Authors: Muir D. C. G. , Rawn G. P. , Townsend B. E. , Lockhart W. L. , Greenhalgh R.
Published: March 2010

The bioconcentration of four synthetic pyrethroid insecticides (cis- and trans-cypermethrin, deltamethrin, fenvalerate and cis- and trans-permethrin) by larvae of the midge Chironomus tentans was studied in sand, silt and clay sediments and water (sediment/water ratio, 1:5). Larvae were exposed for 24 h in sediment and for 48 h in water above sediment that contained 12 to 640 ng/g 14C-labeled cypermethrin and 5 and 50 ng/g of the other compounds. Depuration of radioactivity following transfer to clean sand/water systems was monitored for 96 h. Bioconcentration factors for larvae held in sand ranged from 135 for trans-permethrin to 316 for deltamethrin. Larvae in water above sand accumulated 5- to 15-fold greater concentrations of each pyrethroid than did larvae held in water above silt or clay sediments. The lower bioavailability of each compound to larvae in water above silt and clay was attributed to greater sorption to suspended particulates and to dissolved organic carbon in these systems than in relatively particulate-free sand/water systems. The accumulation of pyrethroids by larvae in silt and clay sediments was best accounted for by the uptake of the dissolved portion of each compound in pore water. Depuration of the four pyrethroids by Chironomus larvae was rapid, with an overall half-life for radioactivity of 27 ± 8 h. Exposure for 24 h in sediments containing 5 ng/g concentrations of each pyrethroid had little effect on the behavior of the larvae, but at higher concentrations the animals were immobilized, although many survived following transfer to depuration experiments.
Toxicity of seven potential polychlorinated biphenyl substitutes to algae and aquatic invertebrates
Authors: Sanders Herman O. , Hunn Joseph B. , Robinson-Wilson Everett , Mayer Foster L.
Published: March 2010

Laboratory studies were conducted to determine the acute or chronic toxicity of seven potential polychlorinated biphenyl (PCB) replacement products (six phosphate esters and one water-glycol mixture) to the alga Selenastrum capricornutum and three species of invertebrates. Significant reductions in algal biomass after 14 d of incubation were measured in tests with five phosphate esters at nominal concentrations ranging from 0.10 to 10 mg/L. The acute toxicity of six phosphate esters tested against a daphnid (Daphnia magna), a midge (Chironomus plumosus) and an amphipod (Gammarus pseudolimnaeus) was moderate, ranging from 1.1 to 18.0 mg/L. The water-gylcol mixture was nontoxic to algae and invertebrates at the highest nominal concentration tested (100 mg/L).

Chronic toxicity tests based on nominal concentrations indicated that five of the six phosphate esters tested against daphnids reduced survival and reproduction at concentrations ranging from 10 to 56 μg/L. whereas only one of three tested against amphipods significantly reduced growth and survival at concentrations of 31 to 128 μg/L. Emergence of midges exposed to three phosphate esters for 30 d was significantly reduced at concentrations of 36 to 319 μg/L. The water-glycol mixture tested was much less toxic to algae and invertebrates than were the phosphate esters. These data indicate that the potential hazard of phosphate esters to the environment is significantly less than that of PCBs.
Laboratory tests evaluating the effects of cadmium on freshwater protozoan communities
Authors: Niederlehner B. R. , Pratt J. R. , Buikema A. L. , Cairns J.
Published: March 2010

Naturally derived protozoan communities developed on polyurethane foam (PF) substrates were used to evaluate the toxic effects of cadmium. The ability of the communities to resist displacement from a structural equilibrium in acute cadmium exposures was evaluated. The number of species remaining on substrates after 2 d was inversely related to cadmium concentration. The concentration required for a 50% reduction in species number relative to the control (EC50) was 4,000 μg Cd/L. Chronic effects were evaluated by observing the colonization of barren PF islands from a species source (PF epicenter) for 28 d. The species occurring on islands over time and the autotrophic index (AI) of substrate communities were determined. The equilibrium species number on islands declined with increasing cadmium concentrations, and AI increased with cadmium concentration. EC20s for measures of colonization were consistently near 1 μg Cd/L. However, epicenters exposed to 9.5 μg Cd/L were not significantly different from controls in species number or AI. This discrepancy in effect levels between PF islands and epicenters is consistent with a relationship between stress tolerance and successional maturity. Levels of toxicity were consistent and reasonable when compared with other cadmium data. The tests compared favorably to single species toxicity tests in time and cost, yet had the advantages of using indigenous species and incorporating emergent properties of communities, such as predation, competition and succession.
Sensitivity of rainbow trout early life stages to nickel chloride
Authors: Nebeker Alan V. , Savonen Carol , Stevens Donald G.
Published: March 2010

Four acute tests (96-h) with juvenile fish and four early life stage tests with embryos and larvae were completed with rainbow trout (Salmo gairdneri). Ninety-six-hour flow-through LC50 values for juveniles ranged from 8.1 to 10.9 mg/L nickel. Two early life stage tests were started with newly fertilized eggs, one test was started with eyed eggs and one test was started with pre-swim-up larval fish. No observed effect levels (NOEL), the highest nickel concentration without statistically significant adverse effects, for the two tests with newly fertilized eggs were less than 35 and 35 μg/L. The NOEL for the tests starting with eyed eggs and larval fish was 134 μg/L nickel. Early life stages were most sensitive when newly fertilized eggs were initially exposed, followed in sensitivity by eyed eggs, larval fish and juvenile fish.
Quantitative structure-activity relationships: Molecular structures and different modes of exposure affecting transport and toxicities of chemicals: QSAR analysis
Authors: Lien Eric J.
Published: March 2010

Although relatively few systematic studies have been reported on the disposition of various toxicants or pollutants, considerable effort has been devoted to disposition studies on various drugs and simple organic molecules. Our group and others have in the last few years reported the quantitative structure-activity relationships (QSAR) on the absorption, distribution and metabolism of several series of organic compounds. The mathematical model embodies the concept of the pH partition hypothesis and the Sutherland-Einstein diffusion equation, as well as Hansch's parabolic model. For most exogenous molecules of intermediate mol wt (102 to 104), passive diffusion through the lipoprotein barrier appears to be the most important route among the known mechanisms of absorption, with an ideal lipophilic character (log P0) around 0.5 to 3. For polar and/or high mol wt compounds (>104) passage through interstitial space becomes mainly a negative function of log mol wt. High mol wt compounds and strong acids and bases (highly ionized) should not be absorbed readily based on the generalizations obtained. However, this does not eliminate the adsorption or binding of these compounds onto the membrane, or direct tissue damage caused by the strong acidity or basicity. Other mechanisms of absorption such as pinocytosis of liquid droplets and phagocytosis of solids are possible, but no quantitative data are available for analysis. Evidence is also presented to show that strong acids or bases can be absorbed as ion pairs with appropriate counter ions.

Specific examples of QSAR using the following general equation and its simplified forms are presented

log A = -a · (log P)2 + b · log P + c · log (U/D) + d · log mol wt + e · χ + f.

The types of compounds discussed include nonelectrolytes, weak acids and bases, cationic molecules, strong acids, surfactants and some high mol wt substances. Relationships of the absorption via different routes (e.g., gastric, intestinal, percutaneous and corneal) are compared.
Quantitative structure-activity relationships for the acute toxicity of chlorobenzenes to Daphnia magna
Authors: Bobra Alice , Shiu Wan Ying , Mackay Donald
Published: March 2010

The relationships between physical-chemical properties of aqueous solubility, octanol/water partition coefficient, vapor pressure, boiling and melting points and Henry's Law constant are discussed and illustrated for the chlorobenzenes. It is suggested that a critical review of such data is an essential component of quantitative structure-activity relationship (QSAR) development and can elucidate the potential for air/water and organism/water partitioning during bioas-says. Experimental 48-h EC50 data are reported for Daphnia magna in a closed system and relationships established between EC50, solubility and octanol/water partition coefficient. It is suggested that when presenting QSAR data, logarithmic plots should be prepared of the toxic concentration versus both solubility and octanol/water partition coefficient. The results indicate that in this case the toxic effect is nonspecific in nature and that the EC50 is controlled primarily by organism/water partitioning.
A field test of the exams model in the Monongahela River
Authors: Pollard James E. , Hern Stephen C.
Published: March 2010

Although there are many aquatic fate and transport models that predict environmental concentrations of pollutants over time or distance, the science of model validation is in its infancy. It has been recommended that high priority be given to future experimental work to field-validate existing models. This article presents a comparison of model predictions of phenol concentration downstream from a steel mill effluent derived from the Exposure Analysis Modeling System (EXAMS) with ambient phenol concentration data collected from the Monongahela River in Pennsylvania.

The model predicted oxidation and biolysis as the most significant fate pathways for phenol degradation in the Monongahela River. Bacterial numbers were very low in river water, however, reducing the importance of the biolysis pathway. Agreement between observed levels of phenol and predicted model output was best achieved when a first-order decay of total molar oxidants in the water column was simulated by altering EXAMS molar oxidant input values.
Variation in tissue burdens of polycyclic aromatic hydrocarbons in indigenous and relocated oysters
Authors: Pittinger Charles A. , Buikema Arthur L. , Hornor Sally G. , Young Roderick W.
Published: March 2010

Levels of polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography in indigenous oysters (Crassostrea virginica) from three rivers in the southern Chesapeake Bay. Accumulation and depuration rates of PAHs in oysters were measured in situ by relocation experiments between industrially impacted and nomimpacted sites. Elizabeth River oysters at Norfolk, Virginia, contained the highest PAH tissue burdens among oysters from the rivers sampled; the sum of six PAHs identified was 3 9 ppm dry weight. PAH levels in James River oysters ranged from 0 to 2 3 ppm at Wreck Shoals near Newport News, Virginia No PAHs were detected in oysters from the Piankatank River In accumulation experiments, PAH levels increased from 0 to as much as 11 7 ppm dry weight within 3 d of exposure in the Elizabeth River, they then stabilized Depuration or transformation of PAHs in Elizabeth River oysters to undetectable levels occurred within 4 d of relocation to the Ware River Differences in oyster PAH levels generally corresponded with the degree of industrial and urban development and shipping traffic in the habitats.
A comparison of the effect of four benchmark chemicals onDaphnia magnaandCeriodaphnia dubia-affinistested at two different temperatures
Authors: Cowgill U.M. , Takahashi I.T. , Applegath S.L.
Published: March 2010

The purpose of this study was to compare the sensitivity of Ceriodaphnia dubia/affinis with that of Daphnia magna to chlorobenzene, phenol, diethanolamine and ethylene glycol at 20 and 24°C. Static acute toxicity tests (48-h) were carried out at these temperatures in environmental chambers devoted only to toxicity studies. The majority of toxicity tests were carried out non-concurrently, in triplicate, and in each triplicate series the concentrations were randomly assigned within the appropriate ranges.

Response differences of the two organisms at the two test temperatures to the four benchmark chemicals are of the same order of magnitude in each case. D. magna exhibited no statistically significant difference in its response to phenol, diethanolamine and ethylene glycol at the two test temperatures. However, D. magna is less sensitive to chlorobenzene at 24°C than at 20°C. C. dubia/affinis is more sensitive to phenol, diethanolamine and ethylene glycol at 24°C than at 20°C. Like D. magna, C. dubia/affinis is less sensitive to chlorobenzene at 24°C than at 20°C, but the difference for the latter is not statistically significant.

A comparison of the two organisms shows that C. dubia/affinis is more sensitive to the four benchmark chemicals at 24°C than at 20°C. At 20°C, C. dubia/affinis is more sensitive to chlorobenzene and ethylene glycol than is D. magna, but the response to phenol and diethanolamine is the same for both organisms.
Phytotox database evaluation of surrogate plant species recommended by the U.S. environmental protection agency and the organization for economic cooperation and development
Authors: Fletcher John S. , Muhitch Michael J. , Vann David R. , McFarlane James C. , Benenati Francis E.
Published: March 2010

The U.S. Environmental Protection Agency and the Organization for Economic Cooperation and Development have recommended or are considering recommendations for phytotoxicity testing. A study was conducted to determine the amount of quantitative data published on the species suggested in those tests. Also, the sensitivity to herbicide applications was examined by use of a computerized database, PHYTOTOX, developed at the University of Oklahoma. The format and content of this database permitted an analysis of data reported in more than 3,500 publications. Such a comprehensive consideration of data was possible only through the use of the PHYTOTOX database and, as a result, the computer analysis reported herein can be viewed as a novel approach in addressing plant toxicology questions.

Although 23 plant species were considered, adequate data for making toxicological comparisons were available for only six species: oat, wheat, corn, sorghum, cucumber and soybean. Oat and wheat, which are monocotyledons, gave the most sensitive responses to the widest range of plant herbicides. Cucumber was the most sensitive dicotyledon evaluated. Corn and soybean appeared to be relatively insensitive.

The lack of published information on most of the recommended plants emphasized the need for additional toxicological studies to establish the merit of using these plants for chemical screening assays.
Differential toxicity and uptake of two fenvalerate formulations in fathead minnows(Pimephales promelas)
Authors: Bradbury Steven P. , Coats Joel R. , McKim James M.
Published: March 2010

The influence of the commercial emulsifier on the acute toxicity and uptake of fenvalerate [(R,S)-α-cyano-3-phenoxybenzyl(R,S)-2-(4-chlorophenyl)-3-methylbutyrate], a synthetic pyre-throid insecticide, by fathead minnows (Pimephales promelas) was examined. Flow-through acute toxicity testing with measured concentrations of technical-grade fenvalerate and a 30% active ingredient emulsifiable concentrate (EC) of the insecticide was conducted. Steady-state LC50 values were reached by 72 and 120 to 168 h, respectively, in tests with technical-grade and EC formulations of this insecticide. Initially, technical-grade fenvalerate was more toxic; the 96–h LC50s for technical-grade fenvalerate and the EC were 0.69 and 0.99 μg/L, respectively. By 168 h, an LC50 of 0.75 μg/L was determined for the EC, indicating that the incipient lethalities of the two formulations were similar. Fenvalerate concentration factors and residue levels in fish showed no significant differences between formulations. Residue levels associated with mortality decreased slightly with increasing fenvalerate water concentrations and ranged (mean) from approximately 1,000 to 1,500 ng/g. Levels in fish that survived testing increased with increasing exposure concentrations and ranged from about 600 to 900 ng/g. Concentration factors of 187 to 1,860 were calculated, with a mean of 1,670, as determined from fish that survived testing. The time required to accumulate residues was greater with the EC and contributed to a significantly slower uptake rate. Slower fenvalerate uptake in the presence of emulsifiers seemingly resulted in the initially lower toxicity of the EC formulation.
Accumulation of zinc by rainbow trout as influenced by pH, water hardness and fish size
Authors: Bradley R. W. , Sprague J. B.
Published: March 2010

The intrinsic toxicity of zinc within fish may be defined as the amount of zinc present in the gills (the site of acute toxicity) at death. This intrinsic toxicity was similar in rainbow trout (Salmo gairdneri Richardson) that were exposed to zinc in acid or neutral water (pH 5.5 or 7.0) and in hard or soft water (total hardness 390 or 30 mg CaCO3/L). Since much more zinc was needed in the water to cause death at low pH and at high hardness, these conditions must alter the uptake and/or excretion dynamics of zinc in gill tissue to produce a slower rate of zinc accumulation. Additional evidence supporting this conclusion is presented. A 17-fold increase in fish size, from 1.7 to 29.0 g, reduced tolerance of zinc by a factor of 3.2, whereas a 14-fold increase in fish size, from 1.3 to 18.2 g, reduced the median lethal time by a factor of 2.7. This reduced tolerance and resistance in larger fish appeared to result from increased intrinsic toxicity of zinc. All sizes of fish showed similar rates of zinc accumulation in the gills, of about 40 μg/g · h.
Biodegradation of chemicals in the subsurface environment: Influence of microbial adaptation on the fate of organic pollutants in ground water
Authors: Wilson John T. , McNabb James F. , Cochran Jack W. , Wang T. Helen , Tomson Mason B. , Bedient Philip B.
Published: March 2010

A plume of contaminated groundwater originating from an abandoned disposal pit for wood-creosoting waste was characterized. The important organic contaminants in the plume include naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, dibenzofuran and fluorene at individual concentrations of 1,000 to 100 μg/L. Core material from the site was studied to determine if organisms in the subsurface could adapt to this waste and if biological activity influenced the disposition of the plume. Biodegradation of these organic pollutants in subsurface material from the margin of the plume was rapid. No biodegradation of the pollutants was detected in pristine subsurface material from the same geological structure. As a result of this adaptation, the disposition of the plume was not controlled by the rate of utilization of the pollutants by the microorganisms but by the extent of utilization allowed by the supply of oxygen.
Biological methods for the restoration of contaminated aquifers
Authors: Lee M. D. , Ward C. H.
Published: March 2010

Contamination of aquifers is a serious threat to groundwater supplies. Once an aquifer is contaminated, it may remain so for many years. Biological methods for restoring aquifers polluted by organic compounds offer a promising solution. Techniques such as in situ treatment by stimulating the indigenous microbial population or withdrawal of the contaminated groundwater and treatment by conventional wastewater treatment processes have been used successfully. Mutant and acclimated microorganisms can be used in these systems in attempts to increase the rate of degradation of recalcitrant compounds. Stimulation of the indigenous microbial population by the addition of oxygen and nutrients has been shown to be effective in the removal of petroleum products, iron and manganese, and organic solvents. Acclimated and mutant strains of bacteria have been inoculated into treatment reactors and into soil to degrade various organic chemicals. Polluted groundwater also has been withdrawn and treated by activated sludge processes. While some of these processes have not been adequately tested under field conditions and may be limited in applicability, biological methods are effective in restoring some contaminated aquifers.
Photooxidant activity in natural waters
Authors: Ross Ronald D. , Crosby Donald G.
Published: March 2010

After exposure to sunlight or laboratory UV light, sterilized water samples (or their reconstituted concentrates) from California and Hawaii oxidized several common environmental contaminants, including ethylenethiourea, thiobencarb, DDE and aldrin, which do not absorb ultraviolet radiation appreciably in the sunlight wavelength region. Unirradiated controls were inactive. The generated oxidant remained active in the water samples for at least 60 min in the dark at ambient temperature. Tryptophan and tyrosine were isolated as causative agents but were not the actual oxidants. Such light-induced degradation reactions have important implications for the environmental fate of chemicals in water and for environmental modelling.
Effect of organic chemicals on growth and reproduction in the marine red alga Champia Parvula
Authors: Thursby Glen B. , Steele Richard L. , Kane Michael E.
Published: March 2010

A previously developed static-renewal toxicity test was used to test the effect of 10 organic chemicals on the growth and reproduction of the marine red alga Champia parvula (C. Agardh) Harvey. The test measured vegetative growth, formation of tetrasporangia (site of meiosis — asexual spore production) and production of cystocarps (evidence of sexual reproduction). The procedure was used to test the effects of one ketone (isophorone), two volatile hydrocarbons (benzene and naphthalene), three phenols (phenol, 2,4,5-trichlorophenol and pentachlorophenol) and four chlorinated hydrocarbons (2,4-dichlorophenoxyacetic acid, endosulfan, pentachloroethane and toxaphene). Chronic values were determined for vegetative growth and formation of reproductive structures based on statistically significant decreases from control levels. Absence of reproductive structures was also used to determine chronic values. No endpoint was consistently more sensitive than any other, and the ranking of the compounds from most to least toxic was similar regardless of the endpoint used. The results of these tests indicate that the Champia test is often as sensitive or more so than the most sensitive aquatic animal test and is almost always more sensitive than microalgae tests, demonstrating the importance of conducting chronic tests with the previously overlooked macroalgae. The test is easily conducted, sensitive and reproducible.
Characterization and evaluation of JP-4, jet a and mixtures of these fuels in environmental water samples
Authors: Roberts Ann J. , Thomas Thomas C.
Published: March 2010

Capillary gas chromatographic data can be used to distinguish between JP-4 and commercial Jet A fuels that have contaminated groundwater. This is accomplished from chromatographic patterns by using normalized area percents of the C-15 and C-16 n-alkane components. Analyses of the neat fuels, mixtures of the neat fuels and of their solvent extract from water have been performed. Analyses of contaminated groundwaters have identified the presence of jet fuel and other distillate fuels similar to diesel fuel. Even with the complex nature of these fuels, percent amounts of each fuel present as a contaminant could be determined. This technique may prove useful in determining the party responsible for pollution of groundwater.
Environmental levels of p,p'-DDE indicate multiple sources
Authors: Hunt W. Grainger , Johnson Brenda S. , Thelander Carl G. , Walton Brian J. , Risebrough Robert W. , Jarman Walter M. , Springer Alan M. , Monk J. Geoffrey , Walker Wayman
Published: March 2010

Studies undertaken to determine the causes of continuing reproductive failures of populations of peregrine falcons (Falco peregrinus anatum) in Texas and California demonstrate exceptionally high levels of DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) in prey species in western Texas and unchanged high levels of DDE since 1969 in the peregrine population of the central coast of California. Although DDE is a derivative of DDT (p,p'-DDT; 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane), levels of DDT were very low in in these samples. These observations follow a recent pattern of DDE contamination in the South and Southwest that is characterized by locally high environmental levels of DDE and low levels of DDT. The virtual absence of DDT indicates that the possible illegal uses of DDT, or the transport of DDT compounds from Latin America by migrating birds, cannot account for all of the DDE in these samples. Another source of environmental DDE is therefore indicated.
Exhaustive steam distillation extraction of aromatic organics from rainbow trout and water
Authors: Meyer Joseph S. , Linder Greg
Published: March 2010

Exhaustive steam distillation extracted several intermediate molecular weight organic chemicals effectively from rainbow trout, but a high molecular weight organic, benzo[a]pyrene, was not extracted. Fish lipids that do not steam-distill appear to retain extremely lipophilic organics in the boiling flask. Therefore, exhaustive steam distillation should be used cautiously in screening effluents for chemicals that are bioaccumulated.
Effect of application methods on movement and degradation of aldicarb residues in Maine potato fields
Authors: Jones R.L. , Hansen J.L. , Rourke R.V.
Published: March 2010

The effect of application methods on movement and degradation of aldicarb residues was studied in a typically stony, Maine potato field by comparing aldicarb applied in-furrow at planting with aldicarb top-dressed at emergence. At the end of the growing season, residues from the at-planting application were found primarily in the top 0.6 m of soil and the residues from the emergence application were found primarily in the top 0.3 m. One year later, the residues were dispersed throughout the top 1.5 m of soil and had been reduced to about 5% of the original application. This study supports other work that has demonstrated that in the northeastern United States and Wisconsin, early aldicarb at-planting applications generally result in greater aldicarb residue movement than do later emergence applications.

The study is also useful in illustrating variability of soil samples, which exhibited an average coefficient of variation of 110%. The results indicate that little information is lost due to compositing samples, so that compositing samples appears to be an option for reducing analytical costs associated with soil studies.
Toxicity of methyl parathion to bats: Mortality and coordination loss
Authors: Clark Donald R.
Published: March 2010

The 24-h oral LD50 of methyl parathion (phosphorothioic acid O, O-dimethyl O-(4-nitrophenyl) ester) to little brown bats (Myotis lucifugus) (372 mg/kg) was 8.5 times the LD50 for mice (Mus musculus) (44 mg/kg). However, orally dosed mice either died or appeared behaviorally normal after 2 to 3 h, whereas many dosed bats, although alive at 24 h, could not right themselves when placed on their backs. The oral dose estimated to cause this loss of coordination in 50% of a sample of big brown bats (Eptesicus fuscus) was one-third or less the LD50 of this species. Cholinesterase activity depression in brains of little brown bats was similar whether dosage was oral or dermal. With death as the criterion, bats proved relatively insensitive to methyl parathion in 24-h tests, but considerations of the chemical's potential to cause coordination loss, leading to capture and death by predators, coupled with bats' naturally low reproductive rates, suggest possible injury to exposed bat populations.
Adaptation of Selenastrum Capricornutum (chlorophyceae) to copper
Authors: Kuwabara J.S. , Leland H.V.
Published: March 2010

Selenastrum capricornutum Printz, growing in a chemically defined medium, was used as a model for studying adaptation of algae to a toxic metal (copper) ion. Cells exhibited lag-phase adaptation to 0.8 μM total Cu (10−12 M free ion concentration) after 20 generations of Cu exposure. Selenastrum adapted to the same concentration when Cu was gradually introduced over an 8-h period using a specially designed apparatus that provided a transient increase in exposure concentration. Cu adaptation was not attributable to media conditioning by algal exudates. Duration of lag phase was a more sensitive index of copper toxicity to Selenastrum that was growth rate or stationary-phase cell density under the experimental conditions used. Chemical speciation of the Cu dosing solution influenced the duration of lag phase even when media formulations were identical after dosing. Selenastrum initially exposed to Cu in a CuCl2 injection solution exhibited a lag phase of 3.9 d, but this was reduced to 1.5 d when a CuEDTA solution was used to achieve the same total Cu and EDTA concentrations. Physical and chemical processes that accelerated the rate of increase in cupric ion concentration generally increased the duration of lag phase.
Statistical analysis of the cladoceran reproductivity test
Authors: Hamilton Martin A.
Published: March 2010

The data from a renewal toxicity test are awkward to interpret if some of the adult organisms die during the experiment. The usual summary statistic is the mean number of young produced per adult, but when some adults die, the mean can be defined in two different ways, the mean overall (MOA) and the mean ignoring mortality (MIM). The MOA will be small if adults die but the MIM is relatively unaffected by mortalities. The MIM estimate is valid only if the effect of the toxicant on survival is not correlated with the effect on production of young. Analysis of data from several 7-d cladoceran renewal tests indicates that this correlation is negligible. For such tests, it appears that MIM calculations provide a valid way to separate the effect of the toxicant on the production of young from the effect on the survival of the adults. For both MOA and MIM, methods of statistical analysis are presented, including methods of point estimation, standard error estimation, interval estimation and significance test calculation.
Effects of sample storage on a copper-spiked freshwater sediment
Authors: Malueg K.W. , Schuytema G.S. , Krawczyk D.F.
Published: March 2010

Freshwater sediment from an Oregon lake was spiked with copper in the laboratory to study the effect of storage on copper toxicity. Peat moss was added to enhance the carbon content of a portion of the sediment. One-half of the sediment samples were stored at 5°C while the other half were frozen (−20°C). At intervals up to 25 weeks, samples were brought to 20°C and 48-h toxicity tests were conducted in 1-liter beakers (200 ml sediment, 800 ml water) using the cladoceran Daphnia magna Straus.

Copper released into the water from the sediment stored at 5°C increased over the first 8 weeks of storage, then decreased. Freezing the sediment attenuated the release of total and soluble copper into the overlying water, resulting in low or no toxicity to daphnids. Based on total copper concentrations in the overlying test water, LC50s ranged from 7 to 44 μg/L in sediments without peat and from 52 to 96 μg/L in sediments with added peat. Soluble copper LC50s for-the same test waters ranged from 3 to 18 and from 25 to 68 μg/L, respectively. No LC50s could be calculated from the frozen sediment tests because of low mortality. Freezing is not recommended as a storage procedure because of its undependability in preserving sediment integrity for toxicity tests.
A field study of physiological effects on fish in lead-contaminated lakes
Authors: Haux Carl , Sjöbeck Maj-Lis , Larsson Åke , Lithner Göran
Published: March 2010

In a field investigation, physiological parameters were studied in whitefish (Coregonus spp.) living in lead-contaminated lakes in northern Sweden. Fish from an uncontaminated lake were used as a reference. The activity of the enzyme δ-aminolevulinic acid dehydratase in blood was inhibited up to 88% in fish from lead-contaminated lakes, as compared with fish from the reference lake, indicating the presence of lead pollution. In addition, higher blood glucose levels and lower plasma sodium content were observed in fish from lead-contaminated lakes. These results suggest that lead affects fish in the environment in a way similar to that observed in laboratory experiments.
Discrimination learning in adult bobwhite quail fed paraquat
Authors: Bunck Christine M. , Bunck Theodore J. , Sileo Louis
Published: March 2010

Adult male bobwhite quail (Colinus virginianus) were fed a diet containing 0, 25 or 100 ppm paraquat dichloride. After 60 d on treated diets, discrimination learning was evaluated with acquisition and reversal tests. The three groups performed similarly on these tests. Dose-related histopathological lesions were not found in liver, kidney or lung tissues.
Structure-activity relationship studies on the toxicities of benzene derivatives: II. An analysis of benzene substituent effects on toxicity
Authors: Hall Lowell H. , Kier Lemont B.
Published: March 2010

The toxicity of benzene derivatives to fathead minnows is analyzed in terms of an additivity model. Each substituent appears to contribute a constant and additive amount to the overall toxicity of the benzene derivatives in the data set. However, the nitro group does display some unusual behavior within the additivity model. The model put forth in a previous article is reexamined with respect to the nitro group contribution. A new set of values for nitro groups is developed, giving a contribution for the mono nitro, meta dinitro and ortho/para dinitro groups. There is a modest improvement in the correlation statistics: r = 0.953, s = 0.243 and F = 81.7 for seven regression variables. Some suggestions concerning mechanism are made based on the toxicity coefficients.
Unsaturated zone studies of the degradation and movement of aldicarb and aldoxycarb residues
Authors: Jones R.L. , Hansen J.L. , Romine R.R. , Marquardt T.E.
Published: March 2010

Unsaturated zone studies to measure the movement and degradation of aldicarb and aldoxycarb residues were conducted in 1983 at seven locations: Maricopa, Arizona; Harrellsville, North Carolina; Blackstone, Virginia; Blissfield, Michigan; Bluecast, Indiana; Pasco, Washington; and Fort Pierce, Florida. The Blissfield and Bluecast studies also included monitoring of tile-drain water and the Fort Pierce test included shallow ground water analyses. These research studies indicate that aldicarb or aldoxycarb residues will not enter drinking water supplies under agricultural conditions similar to those encountered in these seven field studies. Most, if not all, of the residues will degrade in the unsaturated zone at a rate corresponding to half-lives of between 0.5 and 2.0 months. The field studies also demonstrate that aldicarb and aldoxycarb residues degrade at about the same rate.
Effects of high dietary concentrations of glyphosate (roundup®) on a species of bird, marsupial and rodent indigenous to Australia
Authors: Evans D.D. , Batty Marian J.
Published: March 2010

Five zebra finches, Poephila guttata (Gould), allowed unrestricted access to seed containing 5,000 μg glyphosate/g all died in 3 to 7 d, but they may well have died from starvation since their food consumption was drastically reduced. Six finches survived after ingesting seed containing 2,500 μg glyphosate/g for 5 d. The marsupial Sminthopsis macroura (Gould), and two species of hopping-mouse, Notomys alexis Thomas and Notomys mitchelli (Ogilby) (N = 5 controls and 5 treated, for each species) survived on a diet in which the concentration of glyphosate was increased from 625 μg/g to 5,000 μg/g by doubling the concentration of glyphosate in the food every few days during a 23-d period. The only toxic effect observed in the mammals was a marked body weight loss in the treated N. alexis. The data indicate that glyphosate for these four species is in the probably not toxic to slightly toxic category for rating the relative acute toxicity of chemicals.