bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect, uptake and disposition of nitrobenzene in several terrestrial plants
Authors: Farlane C. Mc , Pfleeger T. , Fletcher J.
Published: March 2010

Eight species of plants were exposed to nitrobenzene in a hydroponic solution. Four species experienced no depression of either transpiration or photosynthetic rates, while one was rapidly killed and the other three were temporarily affected but recovered from the treatment. Uptake of nitrobenzene was passive and was shown to be proportional to the rate of water flux in each species. The transpiration stream concentration factor (TSCF) was 0.72. The root concentration factor (RCF) was variable between the species and was higher than expected, presumably due to deposits of insoluble metabolic products. All of the species examined displayed a capacity to chemically alter nonpolar nitrobenzene into both polar and insoluble products. Volatilization of nitrobenzene from the leaves was a major route of chemical loss.
Leaching and transformation of glufosinate-ammonium and its main metabolite in a layered soil column
Authors: Behrendt H. , Matthies M. , Gildemeister H. , Görlitz G.
Published: March 2010

Results from a long-term study on leaching and transformation of the herbicide glufosinate-ammonium (ammonium-DL-homoanalin-4-yl (methyl)phosphinate) in a layered soil column were compared with model calculations. Soil columns with layers of loamy sand and sand were treated with 3 kg/ha glufosinate-ammonium, applied to the soil surface. The soils were irrigated and the leachate was monitored for glufosinate-ammonium and the main metabolite 3-methylphosphinico-propionic acid during a period of 256 d. Calculations for glufosinate-ammonium and the metabolite were performed with the soil column model EXSOL. Linear equilibrium sorption coefficients (Kd) and first-order half-lives were used for fitting effluent curves for both the herbicide and the metabolite. Sorption coefficients were compared with those values estimated from a relation to the clay content derived from batch studies. Fitted half-lives were compared with the results from die-away and 14CO2 evolution studies of both the parent and the daughter compound. The observed leaching of glufosinate-ammonium could be well simulated using Kd (0.5 cm3/g) and half-life (11.2 d). The half-life fitted for the metabolite (10–30 d) was a factor 2 to 3 smaller than that measured with batch degradation experiments. This may be the result of using degradation data estimated by 14CO2 evolution, which only indirectly indicates the disappearance of the compound.
Evaluation of intact soil-core microcosms for determining potential impacts on nutrient dynamics by genetically engineered microorganisms
Authors: Fredrickson J. K. , Bolton H. , Mcfadden K. M. , Li S. W. , Voris P. Van. , Bentjen S. A.
Published: March 2010

Nutrient export from intact soil-core microcosms in leachate or by plant uptake was evaluated as a means to assess the ecosystem impacts from the environmental release of genetically modified root-colonizing bacteria. Intact cores of two soil types, a Burbank sandy loam and a Palouse silt loam, were excavated for use as microcosms, seeded with corn and wheat, respectively, and inoculated with Azospirillum lipoferum transposon Tn5 mutants. Microcosms were leached at 33 d and 67 d after seeding and the leachate analyzed for sulfate, phosphate, ammonium, nitrite, nitrate, dissolved organic carbon and inorganic carbon. Statistically significant differences in leachate nutrient concentrations between treatments were due to differences in soil types, rather than inoculation with the bacteria. The high variation in the concentrations of nutrients in the leachates from replicate microcosms, attributed to real field variation, suggest that the measurement of nutrient export in leachate from microcosms may not be a sensitive indicator of ecosystem impacts. One exception was dissolved organic carbon (and total carbon). A statistically significant difference (p ≥ 0.05) was observed between the microcosms receiving live inoculum and those receiving heat-killed cells for leachate organic carbon concentration. Plant uptake of N, P, S, B, Cu, Fe, Mg, Mn and Zn was not affected by inoculation but the coefficients of variation were considerably lower than for the leachate analyses. It is suggested that, although the leaching of organic carbon from microcosms may be used as a holistic indicator of ecosystem impacts from the release of genetically engineered microorganisms (GEMs), measurements of plant assimilation of nutrients and specific rates of microbial transformation of nutrients may provide more sensitive effects end points.
Survival of the fattest: Implications for acute effects of lipophilic chemicals on aquatic populations
Authors: Lassiter Ray R. , Hallam Thomas G.
Published: March 2010

Simple assumptions for individual toxic response, exchange of toxicant with environmental concentrations and body composition are used in a model to evaluate the effect of lipid variation on toxic response in a subpopulation of similarly sized individuals. This model represents the internal distribution of a chemical such that more hydrophobic chemicals preferentially move into body lipid. Thus, for exposures of equal chemical activity, both increasing body fat and greater hydrophobicities increase the exposure duration that can be withstood without effect. In simulated 96 h bioassays the effect of increased tolerance to higher hydrophobicities was apparent for chemicals whose KOW exceeded 104. These simulations are compared to published observations. Simulations are also compared to other published data for longer-term bioassays. The effect of interspecies gill morphology on toxic response is also explored. It is concluded that variation in lipid can account for much variation in tolerance in a subpopulation of similarly sized individuals; that gill morphology is another variable influencing toxic response; and that, in general, for similarly exposed organisms, the fattest survives the longest.
Toxicant-induced mortality in models of daphnia populations
Authors: Hallam Thomas G. , Lassiter Ray R. , Li Jia , Mckinney William
Published: March 2010

A method to determine the mortality effects of a hydrophobic chemical on a population is proposed. The ecotoxicological protocol is based on individual organism response and is derived from the static theory of “survival of the fattest.” This study, focusing upon effects of mortality and the effects of toxicant stress on population succession, examines the static assessment survival of the fattest in a dynamic population model. A premise in this approach is that risk assessment should not be based solely upon chemical properties of the toxicant and that the biology of the exposed organisms is an important factor in the determination of effects.
Solubility and toxicity of eight phthalate esters to four aquatic organisms
Authors: Defoe David L. , Holcombe Gary W. , Hammermeister Dean E. , Biesinger Kenneth E.
Published: March 2010

Solubility values for eight phthalate esters investigated ranged from 0.020 to 121 mg/L. Acute toxicity tests were conducted with fathead minnows (Pimephales promelas) and all eight phthalate esters. Acute and chronic tests were conducted with rainbow trout (Oncorhynchus mykiss) and Japanese medaka (Oryzias latipes) using di-2-ethylhexylphthalate. In addition, the chronic toxicity of the three di-n-butylphthalates and a mixture of these three phthalates was examined using daphnids (Daphnia magna). Fathead minnow 96-h LC50 values for di-n-butyl-ortho-phthalate, di-n-butyl-tere-phthalate, di-n-butyl-iso-phthalate and α, w-butylene di[o-(4-hydroxybutoxycarbonyl)-benzoate] were 1.1, 0.61, 0.90 and 121 mg/L, respectively. Di-n-octyl-ortho-phthalate, di-n-octyl-iso-phthalate and di-n-octyl-tere-phthalate were not acutely toxic to fathead minnows at concentrations that exceeded the water solubility estimates for each phthalate. Di-2-ethylhexyl-phthalate was not acutely toxic to any tested species at the highest tested concentrations. No significant adverse effects were observed on hatchability, survival or growth of rainbow trout exposed to a mean di-2-ethylhexylphthalate concentration of 0.502 mg/L (the highest concentration tested) in a 90-d embryo-larval test. However, exposure to a mean di-2-ethylhexylphthalate concentration of 0.554 mg/L significantly reduced the growth of Japanese medaka during a 168-d larval test. Significant adverse effects on reproduction occurred in 21-d chronic tests with D. magna at concentrations of 1.91, 0.20 and 0.64 mg/L for di-n-butyl-ortho-phthalate, di-n-butyl-iso-phthalate and di-n-butyl-tere-phthalate, respectively. A daphnid mixture test with these three phthalates showed complete additivity, which suggests a similar mode of toxic action.
Biodehalogenation: Oxidative and reductive metabolism of 1,1,2-trichloroethane by Pseudomonas Putida—Biogeneration of vinyl chloride
Authors: Castro C.E. , Belser N.O.
Published: March 2010

Resting cell suspensions of the camphor-grown soil organism Pseudomonas putida PpG-786, ATCC culture 29607, dehalogenate 1,1,2-trichloroethane by two pathways under aerobic conditions. The dominant pathway (85%) is oxidative (kox, 4 × 10−19 L/org/sec) and leads in sequence to chloroacetic acid and glyoxylic acid. A competitive reductive pathway (15%) (kred, 0.7 × 10−19 L/org/sec) occurs simultaneously and yields vinyl chloride exclusively. Glucose-grown cells are ineffective in these reactions, and carbon monoxide completely inhibits these transformations. These findings implicate cytochrome P-450 cam as the responsible enzyme in vivo. Overall rates of conversion of 1,1,2-trichloroethane by the organism and the isolated enzyme correspond to those obtained previously with ethylene dibromide.

The results suggest that reductive microbial dehalogenation can occur in the environment even under aerobic conditions.
Relationship between bioavailability and hydrophobicity: Reduction of the uptake of organic chemicals by fish due to the sorption on particles
Authors: Schrap S. Marca , Opperhuizen Antoon
Published: March 2010

The uptake of five chlorinated benzenes and three polychlorinated biphenyls by guppies (Poecilia reticulata) from a sediment suspension has been investigated. To examine the availability of these chemicals, the uptake from water has been compared to that from a sediment suspension. In the two experiments, i.e., with and without sediment being present, the total amount of the test compounds was the same. The only difference was that the chemicals were purely dissolved in the water in one system and partly sorbed on the sediment in the other.

For all five chlorobenzenes bioconcentration factors are found to be reduced when fish are exposed in a sediment suspension. The reduction increased with increasing hydrophobicity of the compounds. A relationship is found between the amount sorbed on the sediment and the reduction of the bioconcentration factor. The same relationship was found from results of studies reported in the literature.

This study also showed that small amounts of sediment can be present in the intestines of the fish when the fish are exposed in a sediment suspension. Depending on the affinity of the chemical for the sediment, the concentrations of the test compounds measured in the whole fish can be significantly influenced.
Acute toxicity of a complex mixture of synthetic hexachloroethane (HC) smoke combustion products: II. Determination of component toxicity
Authors: Fisher Daniel J. , Burton Dennis T. , Paulson Robert L.
Published: March 2010

Synthetic hexachloroethane (HC) smoke combustion products are a complex mixture containing Zn, Cd, As, Pb, Al, CCl4, C2Cl4, C2Cl6, C6Cl6 and HCl. The dissolved components of the synthetic HC smoke combustion products mixture are quite toxic to a number of freshwater species, especially a green alga, rainbow trout and water flea. Acute 48-h static bioassays were conducted with neonate Daphnia magna to assess the toxicity of various individual components and mixtures of components of the synthetic HC smoke combustion products mixture. These tests showed that the metals, zinc in particular, were the major toxic component of the mixture. When the chlorinated organics were tested as a group, they caused only minimal toxicity to the daphnids.
New method for determining effluent toxicity using duckweed (Lemna Minor)
Authors: Taraldsen James E. , Norberg-King Teresa J.
Published: March 2010

Duckweed (Lemna minor), a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method is described that measures duckweed frond growth and chlorophyll levels as indicators of growth inhibition. The method requires a small testing volume (15 ml) of reconstituted test medium that is prepared by using commercial grade soil to promote frond and chlorophyll production.

A variety of single toxicants, industrial effluents and wastewater treatment plant effluents were tested. For most chemicals, the duckweed was as sensitive as other frequently used test species. The comparative toxicities to Ceriodaphnia dubia and fathead minnows (Pimephales promelas) with various effluents indicates that, for some industrial effluents, duckweed was the most sensitive indicator used.
Effects of arsenate on growth and physiology in mallard ducklings
Authors: Camardese Michael B. , Hoffman David J. , LeCaptain Leonard J. , Pendleton Grey W.
Published: March 2010

Arsenic (As) has been found at elevated concentrations in irrigation drainwater and in aquatic plants utilized by waterfowl. Mallard (Anas platyrhynchos) ducklings received an untreated diet (controls) or diets containing 30, 100 or 300 ppm As added as sodium arsenate. After 10 weeks blood and tissue samples were collected for biochemical and histological examination. Arsenic accumulated significantly in brain and liver of ducklings fed 100 or 300 ppm but did not result in histopathological lesions. The 300-ppm dietary As concentration decreased overall growth (weight gain) in males, whereas all concentrations of As decreased overall growth and rate of growth in females. Food consumption was less during the first three weeks in the 300-ppm group and during the second week for the 100-ppm group compared to controls. Plasma sorbitol dehydrogenase activity and plasma glucose concentration were higher in the 300-ppm group compared to controls. Plasma triglyceride concentration increased in all As-treated groups. Brain ATP was lower in the 300-ppm group and sodium/potassium-dependent ATPase activity was higher in the 30- and 100-ppm groups. Hepatic glutathione peroxidase activity was lower in the 300-ppm group and malondialdehyde lower in all treatment groups. All treatment levels caused elevation in hepatic glutathione and ATP concentrations. These findings, in combination with altered duckling behavior (increased resting time), suggest that concentrations of As that have been found in aquatic plants (up to 430 ppm dry weight) could adversely affect normal duckling development.
Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality
Authors: Henny Charles J. , Bennett Jewel K.
Published: March 2010

Data from a 1986 field study of white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p, p'-DDE, hereafter referred to as DDE. Eggs from 80 nests (one egg/nest) were tested for shell strength and thickness. Egg contents were analyzed for organochlorines, mercury and selenium; productivity at each nest (minus one egg) was monitored in the field. DDE-DDT concentrations in the eggs ranged from none detected (<0.1) to 29 ppm (wet weight). Shell thickness and shell strength were both negatively correlated with DDE (−0.60, −0.61, respectively), but shell strength deteriorated at a faster rate than shell thickness. Scanning electron micrographs indicated the deterioration in strength was related to changes in ultrastructure as well as to decreased thickness. Fourteen eggs with <0.40 ppm DDE were used to exemplify normal “control” eggs. Of the eggs with higher concentrations of DDE (i.e., ≥0.40 ppm), 11 of 66 were thinner (>2 SD below “control” mean) than normal, 11 of 59 were weaker than normal and 7 eggs were cracked so their strength could not be tested, although thickness was measured. Therefore, 17% of the eggs with ≥0.40 ppm DDE were thinner than normal and 27% were either weaker than normal or cracked. Further, six eggs (four with ≥15 ppm DDE) did not have abnormally thin shells, but did have abnormally weak shells. Nests with abnormal test eggs (thinner, weaker or cracked) produced fewer young than nests with normal eggs. Use of the shell strength parameter provides additional information for better evaluations of reproductive problems. The potential utility of monitoring eggshell quality goes beyond evaluating effects of organochlorines since recent work indicates that other environmental hazards can affect shell quality.
Lead, cadmium and other metals in scandinavian surface waters, with emphasis on acidification and atmospheric deposition
Authors: Steinnes Eiliv
Published: March 2010

Long-range atmospheric transport of pollutants affects the chemistry of heavy metals in natural waters in several ways. First, the direct atmospheric supply of some metals to lakes and their catchments may add strongly to the total burden of these metals in the lake ecosystems. Second, the acidity of the precipitation may enhance the metal fluxes by dissolution of metals originating from mineral material in the catchment or previously supplied by atmospheric deposition and fixed to surface soil or sediment. Furthermore, the acidification of surface waters interferes strongly with the speciation of the metals in the water. The southern part of Scandinavia is considerably influenced by long range atmospheric transport from other parts of Europe. The present paper is a review of recent work in this region related to the occurrence and chemical behavior of lead, cadmium and other trace metals in natural surface waters, with emphasis on the supply from atmospheric deposition. The impact of acidification on the mobility and chemical speciation of the metals is briefly discussed.
Environmental factors affecting the formation of methylmercury in low pH lakes
Authors: Winfrey Michael R. , Rudd John W. M.
Published: March 2010

Recent studies have demonstrated elevated levels of mercury in fish from remote, low alkalinity and low pH lakes. The mechanisms of this enhanced bioaccumulation are poorly understood, but the amount of methylmercury produced in a lake can play a major role. Decreased pH stimulates methylmercury production at the sediment-water interface and possibly in the aerobic water column. Decreased pH also decreases loss of volatile mercury from lake water and increases mercury binding to particulates in water – factors that may increase methylation at low pH by enhancing the bioavailability of mercury for methylation. In anoxic subsurface sediments, decreased pH decreases the rate of mercury methylation, suggesting that methylmercury formation in the water column and at the sediment-water interface may be most important in acidified lakes. Sulfate-reducing bacteria are important mercury methylators in acidified lakes. Whether enhanced sulfate reduction stimulates methylmercury production in low pH lakes is presently unclear, although most of the available data do not support this hypothesis.
Mercury accumulation in yellow perch in wisconsin seepage lakes: Relation to lake characteristics
Authors: Wiener James G. , Cope W. Gregory , Rada Ronald G.
Published: March 2010

We studied relations between lacustrine characteristics and the total mercury (Hg) content of calendar age-2 yellow perch (Perca flavescens) in 10 seepage lakes in north-central Wisconsin. Mean concentrations and burdens (masses) of Hg in whole perch varied widely among lakes, were negatively correlated with lake pH and were positively correlated with total Hg concentration in surficial profundal sediment. Approximately 80 to 90% of the variation in Hg concentration and burden in whole perch was explained with multiple regressions containing two independent variables: either lake pH or alkalinity, and Hg concentration in surficial sediment. Variation among lakes in the Hg concentration in yellow perch was unrelated to their relative rates of growth. The mean concentration of Hg in axial muscle tissue of age-5 walleyes (Stizostedion vitreum vitreum) from five of the study lakes was highly correlated with the mean concentration in whole age-2 perch in the same lakes. We hypothesized that the high Hg concentrations often seen in piscivorous fish in low-alkalinity lakes (relative to high-alkalinity lakes) is at least partly due to a greater dietary intake of Hg in such waters. Furthermore, the analysis of small yellow perch—the preferred prey of adult walleyes and an important forage species for many predatory fishes in the north-central United States—may be an effective approach to assessing Hg bioavailability in the region's lakes.
Mineralization of linear alkylbenzene sulfonate (las) and linear alcohol ethoxylate (lae) in 11 contrasting soils
Authors: Knaebel David B. , Vestal J. Robie , Federle Thomas W.
Published: March 2010

The microbial mineralization of [U-14C-ring] linear alkylbenzene sulfonate (LAS) and [U-14C-ethoxylate] linear alcohol ethoxylate (LAE) was examined in 11 soils. These soils differed in their physical-chemical properties and were obtained from geographically distinct locations. With one exception, they had no previous exposure to synthetic surfactants. Soil samples were amended with trace levels (50 ng/g soil) of each 14C surfactant, and evolution of 14CO2 was measured over time. When appropriate, the data were fitted to a first-order production equation, and first order rate constants and asymptotic yields of 14CO2 were estimated using nonlinear regression. Both surfactants were mineralized without a lag period in every soil tested. Yields ranged from 16 to 71% and 30 to 69% for LAS and LAE respectively. First-order rate constants ranged from 0.14 to 0.63 for LAS and 0.07 to 0.62 for LAE. Mean half-life (across all soils) was 2 d for both surfactants. Community microbial activity, measured as the rate of acetate incorporation into lipids, did not correlate with either the rate or extent of surfactant mineralization. Subjecting these soils to cycles of wetting and drying in the laboratory prior to testing in most cases resulted in more rapid and extensive mineralization. These results indicate that microbial communities in soils have an indigenous ability to degrade low concentrations of LAS and LAE. This ability appears to be ubiquitous since it is present in a wide array of soil types from various locations. In addition, laboratory experiments involving wetting and drying of soils indicated that both the rate and extent of mineralization may be affected by climatological events.
Copper toxicity to Paratya australiensis: III. Influence of dissolved organic matter
Authors: Daly Helen R. , Jones Michael J. , Hart Barry T. , Campbell Ian C.
Published: March 2010

The influence of dissolved organic matter on the toxicity of copper to the Australian freshwater shrimp, Paratya australiensis, was measured using water collected from three sites in Victoria, Australia. A two-ligand model was used to describe copper complexation in these test waters. The binding characteristics of the ligands (i.e., total ligand concentrations and conditional stability constants) were determined using a method combining ion selective electrode and anodic stripping voltammetry.

Ion selective electrode measurements and the two-ligand model were each used to estimate the concentration of copper(II) (the major toxic species) at the LC50 values. Both methods overestimated by a factor of approximately 1.5 to 3 the expected copper(II) concentration at the LC50 values, based on earlier experiments in Melbourne tap water. The agreement seems remarkably good given the many assumptions used in making the comparison and the difficulties encountered with the use of ion selective electrodes in natural waters.
Comparison of measured instream biological responses with responses predicted using the ceriodaphnia dubia chronic toxicity test
Authors: Eagleson Kenneth W. , Lenat David L. , Ausley Larry W. , Winborne Ferne B.
Published: March 2010

Instream toxicity was predicted with whole effluent toxicity tests. These results were then compared to the observed instream response of the aquatic community. Forty-three comparisons were conducted in freshwater flowing systems using Ceriodaphnia dubia chronic toxicity test procedures and standardized qualitative sampling of benthic macroinvertebrates. In 88% of the comparisons there was agreement between both measures. These data suggest that the use of effluent toxicity testing results as a regulatory tool is effective and appropriate. Comparisons used whole effluent toxicity limitations similar to those being written in North Carolina's NPDES permits for discharge to surface waters.
Yolk retinoids (vitamin a) in eggs of the herring gull and correlations with polychlorinated dibenzo-p-dioxins and dibenzofurans
Authors: Spear Philip A. , Bourbonnais Diane H. , Moon Thomas W. , Norstrom Ross J.
Published: March 2010

Little is known of the combined effects associated with chronic, low-level exposure of wildlife to the polyhalogenated dibenzo-p-dioxins, dibenzofurans, certain biphenyls and other related compounds. To examine possible effects upon egg yolk retinoids, herring gull (Larus argentatus) eggs were collected at early (i.e., days 2–12) and late (i.e., approximately day 20) phases of incubation. Analysis of egg yolks by reversed-phase high-performance liquid chromatography revealed compounds that comigrated with all-trans-retinol and all-trans-retinyl palmitate standards. The retinol concentration and the molar ratio of retinol to retinyl palmitate changed significantly between the early and late phases of incubation. Within the 2- to 12-d period of incubation, however, retinoid values were constant. Gull eggs were collected from two breeding colonies on the Great Lakes in 1986 and from five colonies in 1987. In 2- to 12-d eggs, retinol and retinyl palmitate concentrations were significantly different between gull colonies. The molar ratio of retinol to retinyl palmitate was significantly different between colonies and correlated with several indices of polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations quantified in gull eggs from these collection sites. Significant correlations existed between the molar ratio of retinoids and (a) 2,3,7,8-TCDD concentration, (b) toxic equivalents of PCDDs and PCDFs and (c) the sum of PCDD and PCDF concentrations. These results are discussed in the context of sensitive, bioeffects monitoring.
Slowly reversible sorption of aliphatic halocarbons in soils. II. Mechanistic aspects
Authors: Pignatello Joseph J.
Published: March 2010

The mechanism of formation and release of highly immobilized residues of some small nonpolar halogenated hydrocarbons in two surface soils, a stream sediment and an aquifer sediment was investigated. The labile sorbed fractions of compound were removed from treated soils by purging to infinite dilution in aqueous suspensions for 96 h. The remaining slowly reversible (residual) fraction of compound in the soil was quantitated as a function of prepurge sorption conditions. The residual increased nonlinearly with sorption equilibration time and applied concentration. Residuals in whole soils and whole soils pretreated with H2O2 were correlated with soil organic carbon. Among wet-sieved particle size fractions, however, the organic carbon-based concentrations followed the order, sand > silt >> clay. Also, some residual was associated with undecomposed plant matter. Release of the residual into water was greatly increased by pulverization of the soil and by acidification of the soil suspension. The results indicate that the slow release of the residual fraction is caused by molecular diffusion from remote sites in the soil organic matter matrix. Mineral surface and clay interlayer adsorption were ruled out by the finding of low residuals in the clay-sized particles. However, the mineral fraction plays an important role by shielding some of the organic matter in interstitial pores of particle aggregates from equilibrium with bulk solution.
Methods for assessing fertilization and embryonic/larval development in toxicity tests using the california mussel (Mytilus californianus)
Authors: Cherr Gary N. , Shoffner-Mcgee Julie , Shenker Jonathan M.
Published: March 2010

The fertilized eggs, embryos and larvae of the California mussel (Mytilus californianus) were used to develop methods for assessing fertilization and larval development rates, and for conducting toxicity tests in standard exposure chambers and small volume (3 ml) chambers. Because the sperm/egg ratio resulting in high monospermic fertilization rates varied among females, the “optimal” ratio for each female was predetermined in an aliquot of eggs prior to fertilizing the entire batch for bioassay use. The fluorescent DNA probe Hoechst 33342 was used to rapidly differentiate unfertilized, monospermic and polyspermic eggs. Following fertilization of entire batches of eggs based on the predetermined sperm/egg ratio, monospermic fertilization rates of >90% were readily achieved. Fertilized embryos were then used in bioassays conducted in beakers or tissue-culture chamber slides (mini chambers), which could be viewed directly on the microscope. The response of the embryos and larvae to the metabolic inhibitor sodium azide was assessed in both types of test chambers. At 96 h postinsemination at 12°C, veliger or nonveliger larvae were assessed using polarization microscopy to determine the presence or absence of a complete shell. No significant difference in the response to sodium azide was detected between the beakers and mini chambers. This study demonstrates that M. californianus is suitable for static embryo/larval toxicity tests, and that small volume chambers allow successful larval development and eliminate the need for subsampling of larger test chambers. We also demonstrated the value of assessing fertilization rates prior to conducting the bioassay, and present an improved method for examining larval shell development using polarization microscopy.
Avoidance of selenium-treated food by mallards
Authors: Heinz Gary H. , Sanderson Caroline J.
Published: March 2010

Adult, male mallards (Anas platyrhynchos) were given a choice between a control diet and a diet containing 5, 10 or 20 ppm selenium as selenomethionine dissolved in water and mixed into the diet. At 10 and 20 ppm, selenium-treated diets were avoided. Avoidance appeared to be caused by a conditioned response, probably to illness caused by the selenium and not to an aversion to the taste of the selenium.
PCB movement, dechlorination, and detoxication in the acushnet estuary
Authors: Brown John F. , Wagner Robert E.
Published: March 2010

Congener-specific analyses of the PCBs in Acushnet Estuary (New Bedford, MA) sediments and waters were undertaken to identify the PCB alteration and transport processes occurring in coastal marine sediments. These analyses indicated that (a) the PCBs deposited at the sediment sites sampled had originally consisted of Aroclors 1242 and 1254, in widely varying proportions; (b) these PCBs had undergone vertical movement within the sediments, rather than remaining stratified, but not horizontal translocation between sites; (c) they had also undergone extraction into the water, albeit at declining rates, with some consequent changes in composition but (d) the major compositional change was caused by a previously unreported type of reductive dechlorination process, designated Process H. This presumably anaerobic microbial process, subsequently identified at several other locations as well, had selectively removed non-ortho chlorines from most of the higher PCB congeners, especially those associated with acute toxic effects. It appeared to have begun near the upper end of the estuary and not yet reached its lower portions, thus providing a marker for tracing the origin of the PCBs in estuarine water samples.
Evaluation of sucrose as an alternative to sodium chloride in the microtox® Assay: Comparison to fish and cladoceran tests with freshwater effluents
Authors: Ankley Gerald T. , Peterson Gregory S. , Amato Joseph R. , Jenson James J.
Published: March 2010

The toxicity of 44 freshwater effluents was evaluated using the fathead minnow (Pimephales promelas), a cladoceran (Ceriodaphnia dubia) and Microtox® (Photobacterium phosphoreum). The latter assay was conducted with both sodium chloride (NaCl) and sucrose for osmotic protection of the bacteria in an effort to determine whether the use of sucrose increased the sensitivity of Microtox to samples exhibiting toxicity to the fish and cladoceran species. Twenty-three of the effluents tested were toxic to fathead minnows and/or C. dubia; of these, Microtox was sensitive to 10 when tested in NaCl and seven when tested in sucrose. In one instance testing in sucrose predicted toxicity to the fish and cladoceran species when testing in NaCl did not. Single chemical tests demonstrated that Microtox sensitivity was greater to zinc chloride, nickel chloride and methanol when tested in sucrose as opposed to NaCl, about equal to copper sulfate and phenol in sucrose and NaCl, and was far greater to chlorine when tested in NaCl than in sucrose. These results, as well as data from Microtox assays with effluents containing known toxicants, suggest that the use of sucrose, in conjunction with NaCl, for osmotic adjustment in the assay could be helpful as part of a suite of tests for identifying general classes of compounds responsible for toxicity in freshwater effluents.
Dietary accumulation and sustained hepatic mixed function oxidase enzyme induction by 2,3,4,7,8-pentachlorodibenzofuran in rainbow trout
Authors: Muir Derek C. G. , Yarechewski Alvin L. , Metner Donald A. , Lockhart W. Lyle , Webster G. R. Barrie , Friesen Kenneth J.
Published: March 2010

Accumulation of and hepatic monooxygenase induction by 2,3,4,7,8-pentachlorodibenzofuran (PnCDF) were studied in juvenile rainbow trout (Onchorhynchus mykiss) by feeding treated food for 31 d followed by a 180 d depuration period. Efficiency of assimilation was 44 and 41% at exposure concentrations of 9.0 and 0.82 ng g−1 PnCDF, respectively. Depuration of PnCDF followed first-order kinetics with half-lives (based on toluene extraction of 14C-radiolabel corrected for growth dilution) of 61 and 69 d at the low and high exposure concentrations, respectively. Monooxygenase enzyme induction measured by ethoxyresorufin-O-deethylase (EROD) activity in individual trout livers was 84- and four-fold higher after 31 d of exposure to 9.0 and 0.82 ng g−1, respectively, than in livers of unexposed fish. Sustained EROD activity at the high treatment concentrations was observed during the 180 d depuration phase. Ethoxyresorufin-O-deethylase activity declined at approximately half the rate of elimination of PnCDF. No significant differences between growth rates of treated and control fish were found.
Effects of the duration and timing of dietary methyl parathion exposure on bobwhite reproduction
Authors: Bennett Richard S. , Shiroyama Tamotsu , Bentley Ray , Bennett Jewel K.
Published: March 2010

Two northern bobwhite (Colinus virginianus) reproduction tests were conducted concurrently to evaluate how the duration and time of initiation of methyl parathion exposure affected dose-response relationships of reproductive parameters. In the long-term exposure test, pairs of adult bobwhite were fed methyl parathion-amended diets (0, 7, 10, 14, 20 or 28 ppm) for 25 weeks: 10 weeks prior to the onset of laying, 6 weeks as they came into laying condition and 9 weeks during egg laying. In the short-term exposure test, quail received amended diets (0, 10, 14, 20, 28 or 40 ppm) for only three weeks during the egg laying period, followed by a three-week posttreatment period. Fourteen birds died in the long-term test, compared to two in the short-term test. Significant dose-related reductions in daily food consumption, egg production and the number of 14-d-old chicks were observed in both tests during the treatment periods. No dose-related effects on fertility, hatch-ability or chick weights were detected. In the long-term test, there were dose-related decreases in adult body weight, brain and serum cholinesterase activity and female serum calcium concentrations. Cholinesterase and calcium were not measured in the short-term test. Eggshell weights were significantly decreased in both tests, but a dose-related decrease in eggshell strength and thickness was detected only in the short-term test. During the posttreatment period of the short-term test, no dose-related effects on reproductive parameters were observed, except that egg production did not recover until the third week after treatment. Except for the number of adult mortalities, all dose-related effects observed in the long-term exposure test also were observed in the short-term test. The short-term test design had two advantages that reduced variability unrelated to the chemical treatments: infertile and incompatible pairs could be removed from the experiment and pretreatment values could be obtained to serve as controls for each pair.
Effects of dietary methyl parathion on northern bobwhite egg production and eggshell quality
Authors: Bennett Jewel K. , Bennett Richard S.
Published: March 2010

There is a need to develop avian reproduction tests that reflect more realistic exposure scenarios for short-lived pesticides, like organophosphorus and carbamate compounds. The effect of a short-term dietary methyl parathion exposure on northern bobwhite (Colinus virginianus) egg production and shell quality was investigated. Hens in egg production were fed either a methyl parathion diet (0, 14, 20, 28 or 40 ppm) or a pair-fed diet (PF28 and PF40 received the same daily allotment of control feed on a g/kg/d basis as the 28 or 40 ppm-treated hen with whom she was paired) for 8 d. Daily food consumption was significantly reduced in all treatment groups and inversely related to chemical concentration. However, actual chemical consumption was similar for all methyl parathion-treated groups. Body weight, egg production, egg weight and eggshell strength, thickness and weight were reduced in the methyl parathion groups in a dose-related manner. Similar responses were observed in the pair-fed groups, indicating that effects were associated with a pesticide-induced reduction in food consumption. The dietary methyl parathion exposure impacted bobwhite egg production within 3 to 4 d and eggshell quality within 1 d of the onset of treatment.
Toxicity of cadmium in sediments: The role of acid volatile sulfide
Authors: Di Toro Dominic M. , Mahony John D. , Hansen David J. , Scott K. John , Hicks Michael B. , Mayr Suzanne M. , Redmond Michele S.
Published: March 2010

The toxicity of chemicals in sediments is influenced by the extent that chemicals bind to the sediment. It is shown that acid volatile sulfide (AVS) is the sediment phase that determines the LC50 for cadmium in the marine sediments tested. Although it is well known that metals can form insoluble sulfides, it apparently has not been recognized that AVS is a reactive pool of solid phase sulfide that is available to bind with metals. Amphipod sediment toxicity tests were conducted in the laboratory and the observed amphipod LC50s on a normalized cadmium concentration basis, [Cd]/[AVS], is the same for sediments with over an order of magnitude difference in dry weight normalized cadmium LC50s.

Because other toxic metals also form insoluble sulfides, it is likely that AVS is important in determining their toxicity in sediments as well. Most freshwater and marine sediments contain sufficient acid volatile sulfide for this phase to be the predominant determinant of toxicity. The other sorption phases are expected to be important only for low AVS sediments, for example, fully oxidized sediments. From the point of view of sediment quality criteria the other sorption phases would be important for metals with large partition coefficients and large chronic water quality criteria.
Validation of a four-day Ceriodaphnia toxicity test and statistical considerations in data analysis
Authors: Masters Julie A. , Lewis Michael A. , Davidson Daniel H. , Bruce Robert D.
Published: March 2010

This study evaluated the technical feasibility of a shorter alternative to the U.S. Environmental Protection Agency (EPA)-recommended 7-d chronic toxicity test with Ceriodaphnia dubia. The results of 4-d and 7-d Ceriodaphnia dubia toxicity tests, conducted concurrently, were compared using treated municipal effluent, metals, PCP, ethylene glycol, phenol and surfactants. The experimental technique was similar for both studies with the exception of the duration and age of the test species at test initiation. The 4-d static-renewal test was initiated with 3-day-old Ceriodaphnia dubia, and 1-day-old organisms were used in the 7-d tests. The chronic values of the replicated studies, based on survival and young production, were within a factor of two in approximately 70% of the total tests conducted and in all tests conducted with municipal effluent. Based on the available results, the 4-d toxicity study appears to be a technically valid alternative to the EPA-recommended 7-day test, particularly for treated municipal effluent. An important factor in toxicity testing is the use of valid statistical procedures. The validity of the various methods for Ceriodaphnia dubia depends upon their appropriate use; however, it is difficult to justify the widespread use of multiple comparison methods, particularly Dunnett's procedure.
Acute physiological stress responses of juvenile coho salmon (Oncorhynchus kisutch) to sublethal concentrations of garlon 4®, garlon 3a® and vision® herbicides
Authors: Janz David M. , Farrell Anthony P. , Morgan J. D. , Vigers Gary A.
Published: March 2010

Juvenile coho salmon (Oncorhynchus kisutch) were exposed for 4 h to sublethal concentrations of the herbicides Garlon 4®, Garlon 3A®, and Vision®. Trials were performed in a closed-system respirometer that measured oxygen consumption of fish prior to and during a 4-h exposure. At the end of the exposure period, plasma glucose and lactate concentrations, hematocrit, and leucocrit were measured as indicators of acute physiological stress. There were no biologically significant indications of acute physiological stress in fish exposed to Garlon 4, Garlon 3A, or Vision at 5 to 80% of the 96-h LC50 concentrations. The results suggest that threshold herbicide concentrations causing physiological stress in short-term exposure (4 h) in juvenile coho salmon may be higher than the 96-h LC50 value for those herbicides. It was concluded that sublethal concentrations of Garlon and Vision herbicides do not induce significant physiological stress responses in juvenile coho salmon during a 4-h exposure period.
An aquatic environmental safety assessment of linear alkylbenzene
Authors: Gledhill William E. , Saeger Victor W. , Trehy Michael L.
Published: March 2010

Linear alkylbenzene (LAB), the parent material from which the detergent surfactant linear alkylbenzene sulfonate (LAS) is manufactured, has the potential to enter the environment from several sources. Solubility, vapor pressure and soil partition measurements indicate that LAB would be distributed in air or adsorbed to soil or sediment. The material does not accumulate to significant levels in fish (BCF = 35) or undergo chemical or photochemical degradation in screening studies. LAB is readily biodegradable in natural waters with half-lives for various isomers and homologs in the 4- to 9-day range. LAB is not acutely toxic to a variety of aquatic species, other than Daphnia magna, within its water solubility range. For Daphnia, chronic studies in clean water systems indicate both growth and reproduction to be affected in the 10 to 20 μg/L range. LAB is substantially removed by typical sewage treatment plants. Receiving waters collected from sites receiving low sewage effluent dilution generally contain less than 1 μg/L. Based on the ratio of the chronic no-effect level for Daphnia to the environmental concentration, the conservative nature of selected monitoring sites i.e., providing low sewage effluent dilution) and the fact that LAB partitions strongly to particulates in the water column, adequate environmental safety margins exist for LAB.
Iodide binding by humic acid
Authors: Huang Tien-Shang , Lu Fung-Jou
Published: March 2010

Iodide binding by humic acid was studied. The reaction was dose, temperature and pH dependent. A maximum binding of 88% was reached with 2 mg humic acid in 0.15 M Tris buffer. The efficiency of iodide binding by the buffer becomes higher whenever the buffer is slightly alkaline. Iodide binding by humic acid at 60°C is more efficient than that at room temperature or 4°C. The reaction was very rapid and reached equilibrium in 2 h. There are two binding sites for iodide in humic acid. The iodide binding by humic acid is inhibited by depleting of oxygen. The reaction was also inhibited by superoxide dismutase, catalase, thiourea, glutathione and dithiothreitol, but butylated hydroxytoluene and ascorbic acid did not inhibit it. In conclusion: (a) Humic acid can bind iodide efficiently in various buffers, (b) the binding is probably a reaction of oxidation reduction, (c) free radicals are involved in the reaction and (d) free radicals are present in the humic acid.
In vitro cytotoxicity of chlorophenols to goldfish GF-scale (GFS) cells and quantitative structure-activity relationships
Authors: Saito Hotaka , Sudo Masato , Shigeoka Tadayoshi , Yamauchi Fumio
Published: March 2010

GF-Scale (GFS) cells, a fibroblastic cell line derived from the scale of goldfish, were used for the determination of the cytotoxicity of chlorophenols (CPs) and the quantitative structure-activity relationships (QSAR) studies. As the cytotoxicity end point, the amount of neutral red retained by viable cells after exposure to chemicals was quantified. The sequence of cytotoxicity based on the concentration of chemicals that reduced uptake of neutral red by 50% (NR50) was penta-Cl (PCP) > 2,4,5-Cl3 > 2,3,4-Cl3 > 2,3,4,6-Cl4 > 3,5-Cl2 > 3,4-Cl2 > 2,4-Cl2 > 2,5-Cl2 > 2,3-Cl2 > 2,4,6-Cl3 > 3-Cl > 4-Cl > 2,6-Cl > 2-Cl > phenol. The in vitro cytotoxicity of these chemicals was found to be significantly correlated to their in vivo acute toxicity to aquatic species, and NR50 values were correlated with six physicochemical parameters of chlorophenols. Log Pow (n-octanol/water partition coefficient) gave the best correlation in simple linear regression analysis, as is frequently stated in toxicity studies with aquatic animals. Multiparametric linear regression equations yielded improved correlation coefficients and predictive capabilities, including the log Pow and pKa. These results suggest that in vitro fish cytotoxicity assays using the GFS cell lines are useful for ecotoxicity screening of aquatic pollutants.