bluuebunny/crossref_metadata_2025 huggingface dataset:
Interspecies relationships in acute toxicity of chemicals to aquatic organisms
Authors: Leblanc Gerald A.
Published: March 2010

The acute sensitivities of several species of aquatic organisms to chemicals categorized as nonpesticide organics, pesticides and metals were correlated using polynomial regression analyses. All species analyzed—fresh- and saltwater fish, invertebrates and algae—responded similarly to the toxicity of nonpesticide organics. Different groups of organisms responded differently to the pesticides. Different species of fish of the same family responded almost identically to the toxicity of pesticides, whereas fishes of different families responded similarly, but to a lesser degree. No relationship existed between the acute sensitivities of a fish and an invertebrate. A significant correlation was determined in acute sensitivities to metals between bluegill and fathead minnows, and between bluegill and Daphnia magna. The mode of toxicity of metals seems to be the same among species, although the degree of toxicity may differ.
Some adjuvant effects on the fate of fenitrothion and aminocarb
Authors: Weinberger Pearl , Greenhalgh R.
Published: March 2010

The ecotoxicity of six widely-used adjuvants—namely, Aerotex 3470, Atlox, Cyclosol 63, Dowanol, Nonylphenol and 585 fuel oil—were extensively investigated with respect to an algal and forest seed model system. The adjuvants differentially affected the chemical and biological fate of the pesticides. All but Dowanol (> 1000 μg/mL) had the potential to perturb the growth of Chlamydomonas reinhardtil Dang, and the tree seeds of Jack pine (Pinus banksiana Lamb.) and Paper birch (Betula papyrifera Marsh). Aerotex, Cyclosol and Nonylphenol (> 5 μg/mL) were the most active adjuncts tested.
Impact of dispersed and undispersed oil entering a gulf coast salt marsh
Authors: Smith Christopher J. , Delaune Ronald D. , Patrick William H. , Fleeger J. W.
Published: March 2010

The effect of dispersed and undispersed South Louisiana crude oil on the growth of Spartina alterniflora and associated meiofaunal communities was investigated in a replicated experiment conducted in a uniform Louisiana salt marsh. The oil and the oil plus dispersant were applied to open water adjacent to the marsh and forced onto the marsh, using a pump to create a “head” of water that simulated tidal conditions. Neither crude oil nor oil plus dispersant had any inhibitory or stimulatory effect on the growth of S. alterniflora or the meiofaunal communities, including the meiobenthos.
Desorption kinetics of picloram as affected by residence time in the soil
Authors: McCall Philip J. , Agin Gary L.
Published: March 2010

Desorption kinetics of picloram (4-amino-3,5,6-trichloropicolinic acid) was studied as a function of incubation time in seven soils incubated for up to 300 d in the presence of picloram. The amount of picloram readily released from the soil decreased significantly with incubation time. A two-step sorption-desorption mechanism was used to model the observed behavior that can be described in terms of external and internal sorption sites. Desorption from external sites is relatively fast, taking place in less than 5 h, whereas desorption from internal sites can take up to 300 h to reach equilibrium. The amount of picloram sorbed to internal sites increases with residence time in the soil. Implications of this study for the transport of picloram under field conditions and for models describing transport are discussed.
Sorption and toxicity of azo and triphenylmethane dyes to aquatic microbial populations
Authors: Michaels Glenda B. , Lewis David L.
Published: March 2010

Toxicity and sorption of five azo and triphenylmethane dyes to freshwater microbiota were determined to assess, in part, the risks that these dyes may pose to the aquatic environment. The toxicities of Basic Violet 1, Basic Violet 2, Basic Violet 3, Basic Green 4 and Tropaeolin 0 were established by determining the percent survival of microbiota when dyes were incorporated into plating media. Basic Violet 3 was the most toxic, with a mean survival rate of 20.7 ± 6.57% at a dye concentration of 5.0 mg/L. Tropaeolin 0 was the least toxic, with a survival rate of 92.0 ± 9.57%. Survival increased with decreasing dye concentration. Sorption of the dyes to viable cells required from 8 to 24 h to reach equilibrium. Partition coefficients were higher for viable cells than for heat-killed cells, suggesting that a metabolic process may be involved in sorption of these dyes or that autoclaving the cells reduces the organisms' cation exchange capacities.
Environmental exposure assessment: Experience under the toxic substances control act
Authors: Daniels S. L. , Hoerger F. D. , Moolenaar R. J.
Published: March 2010

The Toxic Substances Control Act (TSCA) has focused governmental attention on the process of assessing the hazards from commercial chemicals. Environmental behavior and impact must be projected before the chemical is released. This requires a knowledge of the environment, relevancy of laboratory data, extent of necessary data and interpretation of those data for future impacts. The responsibility for the data rests with the manufacturer. The key criterion involves a determination of “unreasonable risk.” Six axiomatic principles of risk assessment are identified. This involves an interactive and interdisciplinary thought process that is both iterative and staged. A generalized procedure for exposure assessment has been developed. An initial risk assessment comparing projected environmental concentrations with probable effect levels determines the type and quantity of laboratory test data needed. As examples, three new and three existing chemicals with widely differing properties and uses have been evaluated for their potential environmental impacts.
Inter- and intralaboratory variability in Daphnia magna effluent toxicity test results
Authors: Grothe Donald R. , Kimerle Richard A.
Published: March 2010

A nine-laboratory round-robin study of the Daphnia magna static, acute, effluent toxicity test was conducted to examine inter- and intralaboratory variability in test results. A single effluent sample was split and sent to three government, three commercial and three industrial aquatic laboratories. Each laboratory followed a specifically designed test protocol and reported the number of daphnids immobilized in each of seven effluent test concentrations at 24 h and 48 h of exposure. The mean 48-h EC50 value for all data was 5.3% effluent. The range was 3.5 to 9.1% effluent, so there is a factor of 2.6 between the highest and lowest EC50 values. The pooled within-laboratory standard deviation and coefficient of variation were 0.91 and 16%, respectively. Combined inter-and intralaboratory estimates of standard deviation and coefficient of variation were 1.8 and 33%, respectively. The results of this study show that Daphnia magna effluent toxicity data can be reproduced both within and between laboratories when clearly defined test protocols are employed.
A transport model for water-soluble constituents of synthetic oil spills in rivers
Authors: Herbes Stephen E. , Yeh Gour-Tsyh
Published: March 2010

A numerical model was developed to predict dissolved aqueous concentrations of phenolic contaminants resulting from accidental spillage of a synthetic oil into a river. The model (termed SOPTRAN, for synthetic oil pollutant transport) simultaneously solves algorithms for processes of oil slick spreading, oil evaporation, phenolics dissolution, advection and dispersion using an implicit integrated compartment method. To test SOPTRAN, predictions were compared with measurements of phenolics dissolution into underlying water following application of a coal-liquefaction product to two 3.75 × 3.75 × 1 m ponds. The mean of measured concentrations during phenolics dissolution was 84% (coefficient of variation = 43%) of predicted values. With minimal calibration, SOPTRAN adequately described differential rates of dissolution of phenol and C1- to C4-alkylphenol isomer groups. The model was used to simulate a hypothetical 300-m3 (80,000-gal) accidental release of a coal liquid from a barge into a large navigable river under both instantaneous and noninstantaneous (i.e., leakage) spill scenarios.
Comparison of fish toxicity screening data for 55 alcohols with the quantitative structure-activity relationship predictions of minimum toxicity for nonreactive nonelectrolyte organic compounds
Authors: Lipnick Robert L. , Johnson David E. , Gilford James H. , Bickings Charlene K. , Newsome Larry D.
Published: March 2010

A comparison was made between the fish toxicity screening test results at concentrations of 5 to 10 mg/L and the LC50 values predicted by the narcotic quantitative structure-activity relationship (QSAR) equation of Könemann for 55 alcohols containing no additional heteroatom functional groups. The majority of the QSAR-predicted toxicities are consistent with the test data. The results for two chemicals predicted to be toxic but showing no effects were explained by a water solubility cutoff. Five chemicals exhibited toxicity at concentrations 20 to more than 10,000 times below those predicted. Four of these contained a double or triple bond attached to a carbon atom bearing a primary or secondary alcohol moiety. Their toxicity was explained by a proposed pro-electrophile mechanism in which an electrophilic toxicant is produced metabolically by the enzyme alcohol dehydrogenase.
Fish subchronic toxicity prediction model for industrial organic chemicals that produce narcosis
Authors: Call D. J. , Brooke L. T. , Knuth M. L. , Poirier S. H. , Hoglund M. D.
Published: March 2010

A model based on partition coefficient was developed for predicting subchronic toxicities of selected chemicals to fish. Early life stage tests were conducted under flow-through conditions using fathead minnows (Pimephales promelas) as test organisms. Embryos, larvae and juveniles were continuously exposed to chemicals for a total of 31 to 33 d. Test endpoints included egg hatchability, incidence of developmental abnormalities, survival and growth. The “chronic value” for each test was a point estimate of the maximum acceptable toxicant concentration (MATC), and was determined as the geometric mean of the highest test concentration producing no effect and the lowest concentration significantly (p ≤ 0.05) affecting one or more endpoints. Ten industrial organic compounds from four chemical classes (ketones, benzenes, ethers and alkyl halides) were used in model development. All chemicals were considered to induce narcosis in fish in acute toxicity tests. The relationship between estimated MATC n-octanol/water partition coefficient (log P) was expressed by the equation

log estimated MATC (mol L−1) = -0.886 log P - 2.18 (r2 = 0.925).

This model was used to predict subchronic toxicities for eight other alkyl halides and chlorinated benzenes that had been tested with fathead minnows and reported in the literature. The mean ratio for observed chronic toxicity value to predicted chronic toxicity value was 2.00 ± 2.03. Observed values ranged from 0.29 to 6.02 times the predicted values. For the 10 chemicals used in the model, the mean acute/chronic toxicity ratio (96-h LC50/chronic value) was 12.2 ± 8.5.
Structure-activity relationships for organotin compounds
Authors: Laughlin Roy B. , French W. , Guard H. , Johannesen R. B. , Brinckman F. E.
Published: March 2010

The LC50 concentrations of a series of 15 structurally distinct diorganotins (R2SnX2) and triorganotins (R3SnX) were determined for zoeae of the mud crab Rhithropanopeus harrisii. Zoeae were exposed from hatching until metamorphosis, at ˜14 d. The LC50 values varied by almost 4 orders of magnitude, from the least toxic aquated species, dimethyltin (LC50 = 92,276 nM) to the most toxic, tricyclohexyltin (LC50 = 19.8 nM). Within a homologous series, the diorganotin was less toxic than the corresponding triorganotin, but the toxicity of the two classes overlapped, e.g., dicyclohexyltin was more toxic than trimethyltin and about as toxic as triethyltin. Correlations between the Hansch π parameter and the LC50, and between total surface area and the LC50, suggest that aqueous thermodynamic activity (hydrophobicity), a function of the organic ligand attached to tin, controls bioconcentration and thus the lethal dose. This conclusion is substantiated by the observation of a single linear relationship between a sum of Hansch fragment constants and the LC50 values for both the di- and triorganotins. The difference in toxicity between di- and trialkyltins results from a decrease in hydrophobic character when a hydroxyl group is substituted for an organic ligand in the former. Any electronic effect of the organic ligand is overwhelmed by the factors that control hydrophobic behavior, as evidenced by the observed poor correlations with χ.
Predicting the bioavailability of organic xenobiotics to Pontoporeia hoyi in the presence of humic and fulvic materials and natural dissolved organic matter
Authors: Landrum Peter F. , Reinhold Mark D. , Nihart Sheila R. , Eadie Brian J.
Published: March 2010

Dissolved organic carbon (DOC) in water sorbs or binds organic xenobiotics, reducing the amount of compound that is “freely dissolved” and therefore the amount bioavailable to Pontoporeia hoyi. The apparent biological uptake rate constant for each compound is proportional to the inverse of the Aldrich humic acid concentration as a source of DOC. The log of the DOC concentration required to reduce the apparent uptake rate constant by 50% correlates well with the log of the partition coefficient to DOC determined by reverse-phase methodology for partition coefficients as low as 104. Further, the partitioning to DOC determined by reverse-phase methodology and from the toxicokinetics in P. hoyi yields partition coefficients similar to those of Aldrich humics measured as DOC and DOC from Lake Michigan interstitial waters. The partition coefficients determined by the two methods correlate well and only vary by a constant bias of a factor of approximately 3. Thus the partition coefficient determined by reverse-phase methodology can be used to predict the bioavailable concentration of organic compounds in water containing DOC for P. hoyi.
Fate and effects of 3,4-dichloroaniline in the laboratory and in outdoor ponds: I. fate
Authors: Wolff C. J. M. , Crossland N. O.
Published: March 2010

Process analysis and a mathematical model were used to evaluate and predict the fate of 3,4-dichloroaniline (DCA) in 40-m3 outdoor ponds. Six ponds were treated with DCA: three with a nominal concentration of 450 μg/L and three with a nominal concentration of 45 μg/L. These concentrations were maintained in the water by repeated applications during a period of 28 d. The predicted fate of DCA was compared with its observed fate.

The dominant loss process was predicted to be direct phototransformation. Using the mathematical model SOLAR and an empirical correction for cloud cover, the rate constant for this process was calculated to be 0.12 to 0.20 d−1. Observed absorbance data for pond water were used to estimate the rate of indirect phototransformation to be 0.01 to 0.02 d−1. Evaporation, hydrolysis and biodegradation were predicted to be of minor importance. The partition coefficient of DCA between wet sediment and water was predicted to be near unity for the range of observed pH values. From this it was calculated that only 3% of the compound would be sorbed and that, therefore, this process could be neglected.

The observed rate of loss of dissolved DCA from the ponds was 0.11 to 0.17 d−1, in good agreement with the predicted overall rate of loss, i.e., 0.13 to 0.22 d−1. It is concluded that the mathematical model SOLAR provided a reliable tool for predicting the rate of direct phototransformation of organic compounds in natural waters.
Fate and effects of 3,4-dichloroaniline in the laboratory and in outdoor ponds: II. chronic toxicity toDaphniaSPP. and other invertebrates
Authors: Crossland N. O. , Hillaby J. M.
Published: March 2010

The effects of 3,4,-dichloroaniline (DCA) on survival, growth and reproduction of the planktonic crustacean Daphnia magna were evaluated in the laboratory using a procedure based on Organization for Economic Cooperation and Development guidelines. Effects on reproduction, the most sensitive of the measured biological responses, occurred at a concentration of 20 μg/L but not at 10 μg/L or at lower concentrations. These, and similar results reported elsewhere, were used to calculate the maximum acceptable toxicant concentration (MATC) for D. magna.

In acute toxicity tests with D. magna and D. longispina the 48-h EC50 values were 290 and 440 μg/L, respectively. An estimate of the MATC for D. longispina was then obtained by multiplication of the MATC for D. magna by the ratio of the 48-h EC50 values for the two species.

A field experiment was carried out to compare the chronic toxicity of DCA in the laboratory with effects on populations of zooplankton and communities of macroinvertebrates in outdoor ponds. Three ponds were treated with DCA at a nominal concentration of 45 μg/L and three at 450 μg/L. These concentrations were maintained in the water for 28 d. Three untreated ponds were used as controls. Population densities of the dominant species of zooplankton were monitored before, during and after treatment with DCA. Samples of the macroinvertebrate communities were taken immediately after the end of treatment. Birth, death and growth rates of D. longispina populations were monitored using Perspex cylinders to confine samples of adults in situ for periods of 24 h.

Population densities of D. longispina were significantly affected (p ≤ 0.05) by both treatment levels. There were no adverse effects on the population densities of two species of copepods and no changes were observed in the structure of macroinvertebrate communities. It was concluded that the Cladocera were much more susceptible to DCA than were other groups of invertebrates in the outdoor ponds.

Birth and growth rates of D. longispina populations were highly sensitive to the effects of DCA. They were depressed when concentrations of DCA were maintained at a level greater than the MATC and increased rapidly when concentrations decreased below this level. Thus, the MATC, derived from the results of toxicity tests, provided an accurate estimate of threshold concentrations affecting field populations of D. longispina.
Reduction in bioavailability to bluegills of polycyclic aromatic hydrocarbons bound to dissolved humic material
Authors: McCarthy John F. , Jimenez Braulio D.
Published: March 2010

The uptake, depuration, metabolic fate and bioaccumulation of two polycyclic aromatic hydrocarbons (PAH), [14C]naphthalene (NPH) and [14C]benzo(α)pyrene (BaP), by bluegill sunfish were determined in the presence and absence of dissolved humic material (DHM) (20 mg C/L) The effect of binding to DHM on the bioavailability of PAH was analyzed by multicompartment kinetic models to determine the relative rates of uptake of PAH dissolved in water versus that bound to DHM. DHM reduced the accumulation of BaP by 90% (97% of BaP bound to DHM) but had little effect on uptake of NPH (2% bound to DHM). The rate coefficients for uptake of bound PAH were only 0 to 10% of the uptake of dissolved PAH. The potential for biotransformation has an important role in bioaccumulation by fish. Although accumulation of total radioactivity (PAH and metabolites) is 10-fold greater in fish exposed to BaP than in fish exposed to NPH, BaP is extensively metabolized whereas NPH is not. Consequently, the bioconcentration of the parent NPH greatly exceeds that of the parent BaP. Because more hydrophobic PAH, such as BaP, have a high affinity for binding to DHM and rapid rates of biotransformation, these interactions may act to mitigate the biological impact of those very hydrophobic PAH having the greatest potential for bioaccumulation and transfer to humans via food chains.
Adaptation of estuarine ecosystems to the biodegradation of nitrilotriacetic acid: Effects of preexposure
Authors: Pfaender Frederic K. , Shimp Robert J. , Larson Robert J.
Published: March 2010

The biodegradation of nitrilotriacetic acid (NTA) was examined in three estuarine ecosystems, one of which had been exposed previously to the chemical. Biodegradation was measured as the conversion of radiolabeled NTA to 14CO2, 14C-labeled cells and the amount of label remaining in solution. The relatively unpolluted Newport River estuary system in North Carolina metabolized NTA slowly, with no apparent increase in rate over time. Jamaica Bay in New York showed an adaptation response, with approximately 50 d required for the onset of relatively rapid rates of biodegradation. The Fraser River estuary in Canada, exposed to NTA for more than 10 years, showed rapid degradation with no lag period at a concentration of 10 μg/L. At 100 and 2,000 μg/L, short lag periods (2 to 4 d) were observed before rapid degradation rates were achieved. Measurements of NTA-degraders indicated that the Fraser River estuary contained 650/ml versus fewer than 10 in the Newport River and Jamaica Bay communities. The results demonstrate that NTA can be degraded by estuarine microorganisms. Estuarine bacteria will adapt to the presence of NTA in the environment and, after adaptation, can respond to increased levels of the compound after relatively short lag periods.
Microbial metabolism of chlorophenolic compounds in ground water aquifers
Authors: Suflita Joseph M. , Miller Gary D.
Published: March 2010

The metabolism of phenol and various chlorophenols was studied in groundwater aquifer microcosms. Flow-through column microcosms containing pristine aquifer material were used to assess aerobic biodegradation processes. Reductive metabolism of the substrates was studied in serum bottles filled with aquifer material contaminated by municipal landfill leachate. We found that microorganisms present in an actively methanogenic aquifer were able to metabolize chlorophenols by replacing the halogen substituents with hydrogen atoms. The identity of the dehalogenated intermediates was confirmed by mass spectrometry for a model substrate and by cochromatography for others. Complete removal of the aryl halides was necessary before the phenol intermediate could be mineralized to methane and carbon dioxide. However, the chlorophenols tended to persist in anoxic microcosms containing material from the same aquifer but from a non-methanogenic site. Metabolism and acclimation of chlorophenols and phenol was noted in aerobic microcosm studies, but the degradation pathway(s) were not established.
Short-term fish and amphibian embryo-larval tests for determining the effects of toxicant stress on early life stages and estimating chronic values for single compounds and complex effluents: Complex mixtures
Authors: Birge Wesley J. , Black Jeffrey A. , Westerman Albert G.
Published: March 2010

A short-term embryo-larval test is described for use with single compounds or complex effluents. Exposure was initiated soon after fertilization and maintained for 4 d after hatching, which gave an exposure period of 6 to 8 d for a number of fish and amphibian species. Test responses included mortality and teratogenesis. Probit analysis was used to calculate median lethal (LC50) and threshold (LCI) concentrations. Standard statistical tests also were performed to determine no observed effect concentrations. Multiple tests were performed with cadmium as the reference toxicant, using continuous-flow and static-renewal procedures; results substantiated high precision and good repeatability. Cadmium LCI values agreed closely with cadmium chronic values determined in life-cycle studies. The review of published data also supported close correlations between LCIs and chronic values for metals. The procedure also worked satisfactorily for a multiple-species test in which eggs of three species were maintained in mixed populations using the same exposure chambers. The test also was conducted in the laboratory to screen seven major industrial effluents. The test for effluent biomonitoring was further evaluated in two major field studies. As compared with 96-h flow-through acute tests with the fathead minnow, the short-term embryo-larval test was decidedly more sensitive and reliable for characterizing the toxicity of complex effluents.
Investigation of the hepatic mixed-function oxidase system in herring gull embryos in relation to environmental contaminants
Authors: Boersma Dora C. , Ellenton Jennifer A. , Yagminas Algis
Published: March 2010

We measured hepatic enzyme activity in 25-d embryos from eight colonies in the Great Lakes and one relatively uncontaminated colony in the Bay of Fundy. This was done to further investigate the use of the mixed-function oxidase system of herring gull (Larus argentatus) embryos for bioeffects monitoring. The changes in ethoxyresorufin o-dealkylation (ERoD) and the rate of aminopyrene-N-demethylation (APDM) across the Great Lakes were small. However, the rate of aniline hydroxylation (AnH) was significantly depressed in seven of eight colonies when compared with control colony. This suppression was greatest in embryos from the three colonies in Lake Ontario, where mirex levels were highest. Organochlorines were measured in egg homogenates from each colony. There was a significant negative correlation of the rate of APDM with both polychlorinated biphenyl and hexachlorobenzene levels and also of the rate of AnH with mirex levels. In conjunction with the above, an egg injection experiment using three doses each of hexachlorobenzene and mirex was conducted to elucidate these compounds' effects on the enzymes measured. The effects on body weight, liver weight and enzyme activity were small compared with the mortality incurred in the eggs injected with hexachlorobenzene. The embryonic LD50 for hexachlorobenzene was calculated as 4.3 ppm. Mortality in the controls injected with 1,4-dioxane was 20%, and that of eggs injected with mirex was similar to that of controls.
Acute aquatic toxicity tests with acrylamide monomer and macroinvertebrates and fish
Authors: Krautter George R. , Mast Richard W. , Alexander Howard C. , Wolf Claude H. , Friedman Marvin A. , Koschier Francis J. , Thompson Carl M.
Published: March 2010

Aquatic toxicity tests were conducted to determine the acute toxicity of acrylamide monomer to two species of aquatic macroinvertebrates (48-h LC50) and three species of fish (96-h LC50). The test animals were daphnids (Daphnia magna), midges (Paratanytarsus parthenogenetica), rainbow trout (Salmo gairdneri), fathead minnows (Pimephales promelas) and bluegill (Lepomis macrochirus). The organisms were exposed to five concentrations of acrylamide and a control, using intermittent-flow procedures. The proportional diluter system was calibrated and the test system equilibrated before the tests were begun. Acrylamide monomer concentrations were analytically determined at equilibration, initiation and termination of the tests.

Macroinvertebrates and fishes were observed for mortality and abnormal behavior twice daily for the duration of the tests. The calculated LC50s, based on measured concentrations of acrylamide monomer, were as follows: daphnids, 160 mg/L; midges, 410 mg/L; rainbow trout, 110 mg/L; fathead minnows, 120 mg/L; bluegill, 100 mg/L. These values were three orders of magnitude higher than those concentrations previously reported to increase invertebrate mortality under field conditions. The results demonstrated that acrylamide monomer was moderately toxic to the five aquatic organisms studied, under the test conditions utilized.
Characterization of mixed-function oxidase systems of the nestling herring gull and its implications for bioeffects monitoring
Authors: Peakall D.B. , Norstrom R.J. , Rahimtula A.D. , Butler R.D.
Published: March 2010

The hepatic mixed-function oxidase system was characterized in embryonic and nestling herring gulls (Larus argentatus). The activity of aminopyrine N-demethylase decreased significantly with the age of the nestlings. No consistent changes in 7-ethyoxyresorufin O-deethylase, benzo[a]pyrene 3-hydroxylase or cytochrome P450 levels with age were found. Levels of organochlorines were determined in individual livers for the 21-d-old nestlings. Correlations among organochlorine residue levels were good, and the activities of aminopyrine N-demethylase and benzo[a]pyrene 3-hydroxylase correlated with each other and with cytochrome P450 levels. No correlations were found with 7-ethoxyresorufin O-deethylase activity, and none of the enzyme levels correlated with the organochlorine residue levels. However, cytochrome P450 levels correlated with both hexachlorobenzene and oxychlordane levels. The implications for the use of the mixed-function oxidase system for environmental monitoring of exposure to organochlorines and polynuclear aromatic hydrocarbons are discussed.
Characterization of effects of copper, cadmium and nickel on the growth of Nitrosomonas Europaea
Authors: Sato Chikashi , Schnoor Jerald L. , McDonald Donald B.
Published: March 2010

The effects of copper, cadmium and nickel on Nitrosomonas europaea were characterized by growth response. Copper inhibition caused a decrease in the growth rate of N. europaea that occurred immediately after inoculation. Cadmium inhibition caused a sharp decrease in the growth rate that occurred after a certain time period, yielding two distinctive growth rates. Nickel inhibition was characterized by an extended lag phase. The combined effects of copper and nickel affected both growth rate and lag. Combined effects of cadmium and nickel were also observed. The combined effect of nickel and copper was antagonistic with respect to both the growth rate and the lag period. Nickel and cadmium acted synergistically to depress the specific growth rate, but the combined effect was either antagonistic or additive (depending upon substrate concentration) with respect to duration of the lag.
Acute and chronic toxicity of ammonia to freshwater fish: A site-specific study
Authors: Mayes M. A. , Alexander H. C. , Hopkins D. L. , Latvaitis P. B.
Published: March 2010

The toxicity of ammonia to the juvenile stages of the bluegill (Lepomis macrochirus) and the walleye (Stizostedion vitreum), and to the embryo, larval and juvenile stages of the fathead minnow (Pimephales promelas) was determined in support of the development of a site-specific water quality standard for ammonia in the Tittabawassee River at Midland, Michigan. There was little difference among the acute toxicities of ammonia (expressed as un-ionized ammonia nitrogen NH3-N) to the three species tested, with 96-h LC50 values of 1.04, 1.06 and 1.50 mg NH3-N/L for the bluegill, walleye and fathead minnow, respectively. Evaluation of the chronic data showed no concentration-related effects for hatching success and growth. However, there was a significant (α = 0.05) decrease in number of normal larvae at hatch and in larval survival at 0.26 mg NH3-N/L and higher. The maximum acceptable toxicant concentration fell between 0.17 and 0.26 mg NH3-N/L, or 0.21 mg NH3-N/L when expressed as the geometric mean of these values. Both the acute and chronic values derived during this study are similar to those reported in the literature, indicating that, in this case, Tittabawassee River water quality did not influence the toxicity of ammonia to the species tested.
Determination and genotoxicity of nitrogen heterocycles in a sediment from the black river
Authors: West W. Raymond , Smith Philip A. , Booth Gary M. , Lee Milton L.
Published: March 2010

The genotoxicity of nitrogen heterocycles isolated from a sediment taken from the Black River near Loraine, Ohio, in an area that received effluents from the coking ovens of a steel plant was studied. These compounds were isolated by gel permeation chromatography and silicic acid adsorption chromatography from the moderately polar fraction of an organic extract of this sediment. Two complex mixtures of secondary and tertiary nitrogen heterocycles containing three to five aromatic rings were characterized using capillary column gas chromatography with selective detection. Both mixtures induced significant unscheduled DNA synthesis in primary rat hepatocytes and accounted for essentially all of the genotoxicity of the fraction from which they were isolated.
Comparative evaluation of three rapid marine toxicity tests: Sea urchin early embryo growth test, sea urchin sperm cell toxicity test and microtox
Authors: Nacci Diane , Jackim Eugene , Walsh Raymond
Published: March 2010

Three rapid marine toxicity tests were evaluated to determine their potential usefulness in a toxicity testing program: early embryo growth test and sperm cell toxicity test, both using the sea urchin Arbacia punctulata, and Microtox. Toxicity values (EC50s) were derived for eight organic chemicals and five metals using each system. Results were compared with LC50 values for the same chemicals from standard aquatic tests with Pimephales romelas and Daphnia magna and for the metals with Menidia menidia and Mysidopsis bahia. The EC50 values for the sea urchin early embryo growth test for organics and the LC50 values for fish and crustaceans for organics and metals with which the rapid tests were compared were from the literature.

For organic chemicals, EC50s from rapid tests closely approximated LC50s and toxicity rankings, except that the sperm cell test was particularly sensitive to 2,4-pentanedione and 2-methyl-2,4-pentanediol. EC50s for metals were generally comparable with each other and with other tests using embryo and sperm of other sea urchins and oysters but not with LC50s for Mysidopsis and Menidia.

These results indicate the potential value of rapid tests to screen and rank substances for toxicity. Additional information on the usefulness of these tests will be gained through continuing comparisons using a broad spectrum of single substances and complex mixtures with varying modes of action.
Impact of methoxychlor on freshwater communities of plankton in limnocorrals
Authors: Stephenson Gladys L. , Kaushik Narinder K. , Solomon Keith R. , Day Kristin
Published: March 2010

Aquatic enclosures, or limnocorrals (5 × 5 × 5 m deep), installed in a 10-ha mesotrophic lake in southern Ontario were used to evaluate the impact of four concentrations of methoxychlor (300 and 3 μg/L in 1981, and 50 and 5 μg/L in 1982) on plankton communities. Methoxychlor was acutely toxic at 300 μg/L to both the macrozooplankton (Cladocera and Copepoda) and microzooplankton (Rotifera). No recovery in macrozooplankton numbers was observed by the end of the experiment (119 d); however, densities of microzooplankton had recovered by 52 d to levels similar to those in control corrals. Changes in species composition of the microzooplankton community were such that the replicate corrals no longer contained similar rotifer populations.

Methoxychlor at 50 μg/L was toxic to all Cladocera, copepod nauplii and copepodites, and the Chlorophyta. Even at this concentration, numbers of Cladocera did not recover to levels similar to those in the control corrals by the end of the experiment (145 d); however, nauplii and copepodites recovered by 55 and 100 d, respectively. Numbers of Chlorophyta were significantly lowered by 50 μg methoxychlor/L (p %le; 0.05). The observed numerical recovery at 41 d was due primarily to an increase in the density of Kurchneriella lunaris. The biomass of this group remained low in these treated corrals because, despite its numerical increase, K. lunaris contributed little to chlorophyte biomass.

Although 5 μg methoxychlor/L was toxic only to Cladocera and copepodites, recovery occurred within 20 d. Methoxychlor at 3 μg/L had no observable effects on density of plankton or on community structure.

The responses to methoxychlor of the various groups of plankton generally appear to be exposure-dependent, with Cladocera and Chlorophyta exhibiting the greatest sensitivity.
Bioconcentration of hydrophobic chemicals in fish: Relationship with membrane permeation
Authors: Gobas Frank A. P. C. , Opperhuizen Antoon , Hutzinger Otto
Published: March 2010

A model is presented for the bioconcentration in fish of nonpolar hydrophobic chemicals that are not metabolized. The model assumes that diffusion rates through membrane-diffusion layer barriers influence uptake and depuration kinetics in fish. For extremely hydrophobic (log Kd, oct > 3 to 4) chemicals, uptake rate constants in fish are independent of the solute's hydrophobicity, whereas for low to moderately hydrophobic chemicals proportionality between these parameters is observed. Additionally, elimination rate constants for low to moderately hydrophobic chemicals are independent of the solute's hydrophobicity. In contrast, the elimination rate constants for extremely hydrophobic chemicals, such as polychlorobenzenes and -naphthalenes, are inversely proportional to hydrophobicity. In the model presented, this is due to the rates of release from the lipid compartments of the fish. The general relationships between bioconcentration kinetic parameters and hydrophobicity are in agreement with experimental data.
Reproduction and health of mallards fed endrin
Authors: Spann James W. , Heinz Gary H. , Hulse Craig S.
Published: March 2010

Concentrations of 0, 1 and 3 ppm endrin in dry duck mash were fed to mallards (Anas platyrhynchos) starting in December, and health and reproduction were measured the following spring and summer. One male fed 3 ppm endrin died with 2.0 ppm endrin (wet weight), a diagnostically lethal level, in its brain. Birds fed 1 ppm endrin reproduced as well as, if not better than, controls. Birds fed 1 ppm endrin had significantly greater hatching success of fertile eggs than did those fed 0 or 3 ppm, and their clutches hatched significantly earlier than did those of birds fed 3 ppm. Mallards fed 3 ppm endrin appeared to reproduce more poorly than controls, but this finding must be regarded with caution because the results of statistical tests often were not significant. Endrin accumulated in eggs to a mean of 1.1 and 2.9 ppm (wet weight) when fed to hens at 1 and 3 ppm. The concentration of endrin in the carcasses of adults was similar to that in eggs, but the concentration in the fat of adults was about 4 to 7 times higher than in eggs.
Use of size-dependent mortality models to estimate reductions in fish populations resulting from toxicant exposure
Authors: Logan Dennis T.
Published: March 2010

In populations in which the rate of early mortality depends primarily on the size of individuals, growth and size become important determinants of population dynamics. Models based on size and developed for fish populations can provide a means of integrating acute and chronic toxicological observations to predict changes in population size. These models predict population reductions resulting from lethality to eggs and larvae, reduced growth rate, reduced length at hatch and any behavioral or physiological changes that increase either size-dependent or size-independent mortality rates. The dependence of mortality rate on size may arise from developmental changes, size-selective predation, changing energy balances or a combination of these. The biological source of mortality may dictate its mathematical expression. Since the size-dependent mortality modeled here may arise from several common sources, it may be widespread. As a result, reductions in natural populations caused by sublethal toxic exposures may not be unusual. These results suggest that measuring sublethal reductions in early growth that result from toxic conditions may be a meaningful way of estimating potential risks to natural populations.
Effects of copper, nickel and zinc on three species of oregon freshwater snails
Authors: Nebeker Alan V. , Stinchfield Ann , Savonen Carol , Chapman Gary A.
Published: March 2010

Three snail species collected from western Oregon were exposed to metals—Juga plicifera and Lithoglyphus virens, which inhabit cool coastal streams, and Physa gyrina, which is found in Willamette Valley ponds. J. plicifera were exposed in flow-through laboratory tests to copper and nickel, L. virens were exposed to copper, and P. gyrina were exposed to nickel and zinc. J. plicifera had a 96-h LC50 (50% of the test group died) of 0.015 mg/L for copper and a no observed effect level (NOEL, mortality not significantly different from that in control groups) of 0.006 mg/L (30-d survival). J. plicifera had a 96-h LC50 for nickel of 0.237 mg/L and a NOEL of 0.124 mg/L. L. virens had a 96-h LC50 for copper of 0.008 mg/L and a NOEL of less than 0.008 mg/L. P. gyrina had a 96-h LC50 for nickel of 0.239 mg/L, a 96-h LC50 for zinc of 1.274 mg/L and a NOEL for zinc of 0.570 mg/L.
Breaking strength: An alternative indicator of toxic effects on avian eggshell quality
Authors: Carlisle J. C. , Lamb D. W. , Toll P. A.
Published: March 2010

A method for measuring the breaking strength of avian eggshells is presented along with a brief review of the literature relating shell strength to chlorinated hydrocarbon exposure. The effect of dietary DDE on shell strength is compared with its effect on shell thickness in the mallard duck (Anas platyrhynchos L). Shell strength was significantly reduced at a lower dietary DDE concentration than was shell thickness. The potential utility of strength measurement as an end-point in toxicology studies is discussed.
DOWANOL, an environmentally safe adjuvant
Authors: Caux P.-Y. , Weinberger Pearl , Carlisle D. B.
Published: March 2010

Pesticide spray formulations include a variety of adjuvants as wetting agents, surfactants or emulsifiers. DOWANOL TPM (tripropylene glycol methyl ether) is one such adjuvant in current common use in spray formulations of the insecticide fenitrothion. Unlike some other adjuvants which we have tested, DOWANOL appears to have no significant toxicity for duckweed, Lemna minor L., an environmentally important aquatic plant, which has been previously shown to be sensitive to some formulations. Four parameters were monitored, namely, biomass, photosynthetic function, adenosine triphosphate level and changes in the electrical potential of the bathing media. Reported concentrations of DOWANOL in forest pools after spraying are of the order of 1 μg ml−1. We have tested concentrations up to 956 μg ml−1. The highest concentration produced significant functional impairment in the plants, which, however, recovered within 2 d in freshwater. Lower concentrations had no measurable effects. The threshold concentration for DOWANOL toxicity to Lemna is thus about three orders of magnitude higher than observed field concentrations, and we conclude that it therefore can be judged to be a relatively environmentally safe adjuvant.
Ring test of an embryo-larval toxicity test with zebrafish (brachydanio rerio) using chromium and zinc as toxicants
Authors: Dave Göran , Damgaard Birthe , Grande Magne , Martelin Jarl Erik , Rosander Björn , Viktor Tomas
Published: March 2010

A protocol for determination of “no-effect” concentrations on hatch and survival in the zebrafish (Brachydanio rerio) has been evaluated at five laboratories for variability using chromium (K2Cr2O7) and zinc (ZnSO4 × 7H2O) as toxicants. Repeatability (r) and reproducibility (R), expressed as C.V. (coefficient of variation), for logarithmic median survival time ranged between 1% and 9% for r and between 1% and 29% for R depending upon concentration of toxicant. Variability increased at high concentrations, especially for zinc. For logarithmic median hatching time, C.V. for r ranged from 6% to 24% and for R between 11% and 27% for the various concentrations of chromium and zinc. Estimated logarithmic “no-effect” concentrations on survival of zinc and chromium had a C.V. for r below 10% and a C.V. for R below 15% for zinc and below 25% for chromium. Zinc delayed the time to hatch at lower concentrations than those that reduced survival time, for the estimated logarithmic “no-effect” concentrations of zinc on hatch r was around 75% and R around 100%. The “no-effect” concentrations based on all nine or ten tests from the five laboratories were 15 mg Cr/L and 0.5 mg Zn/L. Because of the cumulative toxicity of chromium in fish the chronic “safe” concentration may be considerably lower, but the “no-effect” concentration of 0.5 mg Zn/L for effects on hatching time is consistent with the chronic “safe” concentration found in other species of fish at the same hardness (100 mg/L expressed as CaCO3).
Avoidance responses of schooling fathead minnows (Pimephales promelas) to a blend of metals during a 9-month exposure
Authors: Hartwell S. Ian , Cherry Donald S. , Cairns John
Published: March 2010

Avoidance of a blend of four metals (relative proportions: 1.00 copper, 0.54 chromium, 1.85 arsenic, 0.38 selenium) was determined in fathead minnows (Pimephales promelas) in a steepgradient, laminar-flow chamber. Avoidance responses were determined seasonally during 12 months of laboratory observation for unexposed (control) and metals-exposed fish. Unexposed fish avoided very low concentrations of the blend (29 μg/L total metals). Fish exposed to 98 μg/L total metals preferred elevated concentrations equal to three times the holding exposure concentration (294 μg/L total metals) after 3 months of exposure, mildly avoided concentrations five times the holding exposure concentration (490 μg/L total metals) after 6 months of exposure and were not responsive to concentrations approaching ten times the holding exposure level (980 μg/L total metals) after 9 months of exposure. Activity, as measured by movements per unit time in the avoidance tests, was not affected by long-term exposure or during testing.
Field validation of avoidance of elevated metals by fathead minnows (Pimephales promelas) following in situ acclimation
Authors: Hartwell S. Ian , Cherry Donald S. , Cairns John
Published: March 2010

Avoidance of a blend of four metals (relative proportions: 1.00 copper, 0.54 chromium, 1.85 arsenic, 0.38 selenium) was determined in schools of fathead minnows (Pimephales promelas) in an artificial stream supplied with raw river water and in a natural stream. Control (unexposed) fish were tested in spring in the artificial stream and during summer in the artificial stream and a natural stream. Fish exposed continuously for 3 months to the blend of the four metals (98 μg/L total metals) in river water were tested during summer in the artificial and natural streams. Control fish avoided 71.1 and 34.3 μg/L total metals in the artificial stream in spring and summer, respectively, and 73.5 μg/L in the natural stream. Exposed fish did not respond to metals blends as high as 1,470 or 2,940 μg/L in the artificial and natural streams, respectively. Water hardness, turbidity and physical setting are implicated as possible causative factors in differences among control fish. Results are compared with those of previously reported laboratory studies and the effects of pollution observed in the New River, Virginia.
Relationships between aqueous oxygen concentration and uptake and elimination rates during bioconcentration of hydrophobic chemicals in fish
Authors: Opperhuizen Antoon , Schrap S. Marca
Published: March 2010

Oxygen concentrations in ambient water do not influence the uptake and elimination rates of 2,2′,5,5′-tetra- and 2,2′,4,4′,5,5′-hexachlorobiphenyl in guppies (Poecilia reticulata) after aqueous exposure. It is concluded that both the bioconcentration kinetics and bioconcentration factors are independent of the ambient oxygen regime between 2.5 and 8.0 mg/L.

Since it can be assumed that the volume of water passing over the gills increases proportionally with decreasing aqueous oxygen concentration, it is concluded that for the bioconcentration of extremely hydrophobic chemicals, such as polychlorinated biphenyls, the uptake efficiencies rather than the uptake rate constants are dependent on the aqueous oxygen concentration. The experimental results support the concept that the rate of diffusion of the hydrophobic chemicals inside the fish, and not the ventilation volume of contaminated water passing over the gills, dominates the rates of uptake and elimination.