bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of models that describe the transport of organic compounds in macroporous soil
Authors: Southworth George R. , Watson Kenneth W. , Keller Jenny L.
Published: March 2010

Experiments were conducted on an intact soil column to test the suitability of several transport codes in describing the movement of reactive organic compounds through soil containing preferred flow pathways (macropores). The equilibrium-based advection-dispersion model and the nonequilibrium two-region/two-site model were used to describe the elution of a nonretarded tracer ([14C]methanol) and two retarded tracers (trichlorobenzene and tetrachlorobenzene). The advection-dispersion model proved adequate in describing the movement of the nonreactive tracer but it failed to describe the elution of the hydrophobic organics. The organic tracers required the nonequilibrium model to account for their apparent rapid movement. The two-site model, when calibrated to the trichlorobenzene breakthrough data, successfully predicted the elution of tetrachlorobenzene.
Acclimation to cadmium toxicity by white suckers: Cadmium binding capacity and metal distribution in gill and liver cytosol
Authors: Klaverkamp J. F. , Duncan D. A.
Published: March 2010

Juvenile white suckers (Catostomus commersoni) were exposed for one week to Cd, Zn or Hg at concentrations previously reported to produce acclimation to levels of Cd that would normally induce lethality. Cytosolic fractions from liver and gill filaments were analyzed for their capacity to bind 109Cd and for distribution of Cu, Zn, Cd and Hg. Binding of 109Cd was increased in the cytosolic fraction (peak II), which would contain metallothionein (MTN) from liver of Cd-exposed and Zn-exposed fish, and from gill of Hg-exposed and Zn-exposed fish. This binding was also increased in the low molecular weight fraction (peak III), which would contain glutathione, from liver cytosol of all metal-exposed fish and gill cytosol of Cd-exposed fish. Increases in 109Cd binding in peaks II and III were accompanied by decreases in 109Cd binding in high molecular weight fractions (peak I) containing enzymes from liver cytosol of all metal-exposed suckers and gill cytosol of Cd-exposed fish. Exposures to Cd, Zn or Hg produced relative increases in their respective concentrations in peaks I and II, which corresponded to the order of potency (Hg > Cd >> Zn) for inducing acclimation to Cd toxicity. Concentrations of Zn, Cu, Cd and Hg in peak II were used to provide crude estimates of MTN concentrations. Values of 314 and 33 μg MTN/g tissue were obtained for liver and gill, respectively, from non-exposed fish. Hg, the most potent inducer of acclimation to Cd toxicity, was the only metal that produced increased MTN concentrations in both liver and gill. Zn, the least potent inducer, produced the smallest increase in liver MTN and no increase in gill MTN. Further research that is required to understand the more complex relationships between acclimation to Cd toxicity and cytosolic metal-binding proteins is discussed.
Industrial halide wastes cause acute mortality of snow geese in oklahoma
Authors: Andreasen James K. , Stroud Richard K.
Published: March 2010

An examination of 97 dead migratory waterfowl collected at an industrial facility showed that the birds had had severe gastric and intestinal hemorrhaging. Water samples taken at on-site waste lagoons contained 6,750 mg/L fluoride, 4,500 mg/L bromine and 1,500 mg/L boron. Brain and liver tissues contained high levels of fluoride, as compared with tissues of birds collected at a control site. From the necropsy results, the high concentration of fluoride in the water samples and the elevated tissue residues, we conclude that the birds died from acute fluoride poisoning.
Direct and indirect photolysis of water-soluble azodyes: Kinetic measurements and structure-activity relationships
Authors: Haag Werner R. , Mill Theodore
Published: March 2010

Azodyes dissolved in water containing humic acid (total organic carbon = 5 mg/L) and irradiated with a xenon tamp were transformed primarily by an indirect photoprocess involving 1O2 and/or oxyradicals. Dissociation of the phenolic/naphtholic OH groups of the dyes was the dominant factor in increasing indirect photolysis rates. Simplified structure-activity relationships were developed based on pKa prediction methods and on the observation that the reactivities of the dissociated forms of all the dyes are nearly the same. Products of indirect photolysis could not be identified, but loss of color suggests cleavage of the azo linkage in nearly all cases. Aromatic amines are not likely to be formed.
DI-2-ethylhexylphthalate inhibits the hatching of frog eggs and is bioaccumulated by tadpoles
Authors: Larsson Per , Thurén Anders
Published: March 2010

Frog eggs were exposed to di-2-ethylhexylphthalate (DEHP) added to the sediment in laboratory model systems. The number of successful hatchings decreased as the DEHP concentration was increased. In tadpoles, the uptake was concentration-dependent. The phthalate ester was transported from the sediment to the water, and the extent of the transport was governed by levels of DEHP in the sediment. Our results show that the reproduction of frogs may be negatively affected in aquatic environments polluted with phthalates.
Hexavalent chromium as a reference toxicant in effluent toxicity tests
Authors: Dorn P. B. , Raia J. C. , Rodgers J. H. , Jop K. M. , Dickson K. L.
Published: March 2010

The value of hexavalent chromium as a reference toxicant was investigated by comparing the precision of two laboratories in preparing test solutions, examining the consistency of chromium exposure in the test chambers during experiments and determining the effect of nominal versus measured test concentrations on the calculated toxicity (EC50 or LC50). The sensitivities of the test animals to chromium were also determined.

The coefficients of variation associated with preparing chromium test concentrations were 51 and 63.8% in salt and fresh water, respectively, at one laboratory, and 136 and 14.8%, respectively, at the other laboratory. Hexavalent chromium remained stable in the hexavalent (as prepared) form during the toxicity test, with recoveries ranging from 77 to 114%. The precision of the analytical laboratory in measuring chromium-spiked fresh and salt waters ranged from 0.2 to 9.1%. The impact on the calculated EC50s or LC50s of using analytically measured versus nominal concentrations in the analyses was negligible. A comparison of seven species in 27 tests showed organism sensitivity (mean EC50 or LC50 as mg/L Cr6+) to chromium to be, in decreasing order of sensitivity: Ceriodaphnia sp. (0.031), Daphnia pulex (0.086), Mysidopsis almyra (5.1), Mysidopsis bahia (6.03), Cyprinodon variegatus (21.4), Pimephales promelas (26.1) and Lepomis macrochirus (182.9).

The 48-h LC50s for M. bahia were not significantly different (p < 0.05) either within or between laboratories during a 3-week study; values ranged from 5.49 to 7.72 mg/L Cr6+ in both laboratories (nominally) and from 4.21 to 7.23 mg/L Cr6+ when analytically verified by an independent laboratory. The acute toxicities of chromium to D. pulex differed significantly between laboratories, by almost one order of magnitude. Interlaboratory variability observed in D. pulex tests was attributed to differences in the test organisms' food. As reference toxicant tests, chromium tests are valuable benchmark indices of the relative health of test organisms over time or among laboratories. When toxicity test information is used in critical decision making, such as compliance with effluent permit limitations, a reference toxicant such as chromium contributes to quality control and assurance.
Predictive models for photoinduced acute toxicity of polycyclic aromatic hydrocarbons to Daphnia magna, strauss (cladocera, crustacea)
Authors: Newsted John L. , Giesy John P.
Published: March 2010

The photodynamic, actue toxicities of 20 polycyclic aromatic hydrocarbons (PAHs) to Daphnia magna were predicted by photophysical and physiochemical parameters. The photophysical parameters considered were lowest singlet energy, lowest triplet energy, singlet-triplet splitting energy and phosphorescence lifetime. The physiochemical parameters were first- and second-order connectivity indices and log P values. D. magna were exposed to aqueous solutions of each PAH such that equimolar concentrations in D. magna were achieved. The organisms and the PAHs were then exposed to 120 μW/cm2 UV-A and 25 μW/cm2 UV-B light. Mortality times (min) were recorded and the results reported as median lethal time (LT50). Potency factors (π) were calculated and used to rank the PAHs in terms of relative photodynamic toxicity. Some statistically relevant correlations between individual physical parameters and toxicity were observed. Linear, multiple regression models were poor predictors of photoinduced PAH toxicity. A curve-linear model was developed to predict photoinduced toxicity from triplet energy. Goodness-of-fit chi-square tests were performed and demonstrated that triplet energy was an effective predictor both of observed LT50 and of LT50 values adjusted to a constant PAH concentration. Toxicity data were also analyzed using discriminant functional analysis. A stepwise, canonical correlation parameter selection method separated the PAHs into three toxic categories by using triplet energy and phosphorescence lifetime as variables. This model, which classifies PAHs as very toxic, moderately toxic or nontoxic, was 100% accurate when the model developed from one set of PAHs was tested with a different set.
The effect of suspended solids and naturally occurring dissolved organics in reducing the acute toxicities of cationic polyelectrolytes to aquatic organisms
Authors: Cary G. A. , McMahon J. A. , Kuc W. J.
Published: March 2010

Cationic polyelectrolytes comprise a large group of chemicals designed to react with and flocculate suspended solids. Their primary use is as water clarification aids in the removal of suspended solids from water supplies and from industrial and domestic effluents entering receiving waters. Many of these water-soluble macromolecules exhibit an acute toxicity to aquatic organisms of less than 1.0 mg/L. The interaction of residual amounts of these polymers in receiving waters is unclear. The effects of suspended solids (bentonite, illite, kaolin and silica) and of dissolved organic carbon compounds (humic, fulvic and tannic acids, lignin and lignosite) on the acute toxicities of four cationic water clarification aids to the fathead minnow (Pimephales promelas) and a cladoceran (Daphnia magna) were determined. Bentonite and all of the dissolved organic carbon compounds reduced the toxicities of the polymers by one to two orders of magnitude. The remaining suspended solids had a lesser effect in reducing toxicity.
Stream profile determinations using microbial activity assays and Ceriodaphnia
Authors: Burton G. Allen , Nimmo D. , Murphey D. , Payne F.
Published: March 2010

Microbial enzyme activity, Ceriodaphnia survival and reproduction, and metal concentrations were used as indicators of water and sediment quality along Whitewood Creek, South Dakota. Whitewood Creek receives point and nonpoint sources of metals from the Homestake Mine and City of Deadwood. Several significant correlations were observed between various microbial enzyme activity profiles. Stream concentrations of copper were significantly correlated with glucosidase or galactosidase activity. High correlations were also observed between galactosidase activity and both total cyanide and total dissolved solids. Ceriodaphnia stream profile responses were significantly correlated with chromium and nickel concentrations, but not with microbial activity test parameters. Biological test responses appeared to be associated with metal inputs, supporting the use of the bioindicator test approach in stream profile assessments of macrofauna and nutrient cycles.
Biotransformation of trichloroethene in a variety of subsurface materials
Authors: Barrio-Lage Gladys A. , Parsons Frances Z. , Nassar Raja S. , Lorenzo Pedro A.
Published: March 2010

The abilities of three types of sediment to biotransform trichloroethene (TCE) were compared to determine the influence of environmental factors that differ among sediments of different composition. The results could suggest TCE behavior at spill sites in a variety of subsurface materials.

Microcosms containing water and sediment ranging from predominantly organic material to calcareous rock were spiked to contain 5 mg/L of TCE and allowed to incubate in the dark at 25°C. TCE was completely transformed to cis-1,2-dichloroethene (CIS) in one year by a sandy organic sediment that was contaminated with TCE prior to microcosm construction. Microcosms prepared with crushed rock and water, which contained low microbial biomass, depleted all the TCE spike in 21 months of incubation; however, less than 10% of the depleted TCE was recovered as 1,2-dichloroethene. Sodium acetate was added to selected microcosms for the purpose of increasing active microbial populations; however, this had no effect on the depletion of TCE.
Environmental dechlorination of PCBs
Authors: Brown John F. , Feng Helen , Bedard Donna L. , Brennan Michael J. , Carnahan James C. , May Ralph J.
Published: March 2010

The polychlorinated biphenyls (PCBs) in sediment and/or fish samples from at least five different locations show changes in gas chromatographic (GC) peak distribution indicative of reductive dechlorination. Several different dechlorination processes, each presumably mediated by a different population of anaerobic bacteria with its own distinctive pattern of PCB congener selectivity, appear to be operating. Six of these processes have been characterized in detail as to the changes occurring in each of the 126 individual PCB congeners or isomer groups detectable by capillary GC or GC-MS on a DB-1 column. The patterns of congener reactivity indicate that the observed transformation processes fall into two broad categories: o,m,p-dechlorinations, which remove chlorine atoms from ortho, meta, and para positions, with congener reactivities primarily determined by reduction potential; and m,p-dechlorinations, which take chlorines from meta and para positions only, with relative reactivities determined mainly by molecular shape. Both types of dechlorination preferentially remove PCB congeners of toxicological concern, and both produce lower congeners that are biodegradable by environmental aerobes. Thus, dechlorination in anaerobic sediments permits the detoxification and eventual degradation of environmental PCBs.
Use of ground water in assessment of biodegradation potential in the subsurface
Authors: Thomas J. M. , Lee M. D. , Ward C. H.
Published: March 2010

The use of ground water in lieu of soil to determine the biodegradation potential of organic pollutants in the subsurface was assessed. With one exception, the recovery of viable counts and mineralization of naphthalene in the ground waters, but not the soils, collected from boreholes at an abandoned creosote waste site suggest that ground water may contain a microflora not representative of the subsurface. In samples from an aviation fuel spill, the extent of benzene mineralization in aquifer material and well water (from a nearby monitoring well) was about the same, whereas mineralization of benzene in ground water (from the same borehole as the soil) was 4.5 times less after 28 d of incubation. Rates and extent of naphthalene mineralization and microbial numbers declined in samples of water collected after pumping 0, 3,6, and 9 well volumes from a well in a plume of creosote contamination. A method was developed by which a representative sample of ground water was collected by treating the well and proximate formation with 0.5% H2O2 for 24 h and then continuously pumping for a second 24 h before the sample was collected for experimental use. The data suggest that determination of the biodegradation potential of subsurface pollutants using ground water is tenuous unless precautions are taken to ensure the microflora is representative of the subsurface.
Hepatic aryl hydrocarbon hydroxylase activity of lake trout (Salvelinus namaycush) as an indicator of organic pollution
Authors: Luxon P. Lynne , Hodson Peter V. , Borgmann Uwe
Published: March 2010

Hepatic aryl hydrocarbon hydroxylase (AHH) was measured in lake trout (Salvelinus namaycush) from areas on the Great Lakes and from a small “control” lake in a Provincial Park. The results indicated a geographical distribution of MFO activity in the Great Lakes corresponding to levels of organic chemical contamination. Lake trout from the industrialized area of western Lake Ontario had a 6 to 62-fold-higher enzyme activity compared to all other sites.

A seasonal variation in mixed-function oxidase activity occurred in the two-year study. The AHH activity decreased sharply in the autumn at spawning and increased thereafter. No correlation was found between the sex, age, or size of lake trout and their AHH activities at any location.

This field study demonstrated the utility of measuring MFO activity in lake trout for monitoring biologically meaningful levels of polyaromatic hydrocarbons and chlorinated hydrocarbons in contaminated environments on the Great Lakes.
Day-night differences in volatilization rates of polychlorinated biphenyls from water to air
Authors: Okla Lennart , Larsson Per
Published: March 2010

The transport rate of polychlorinated biphenyls (PCBs) from water to air was followed in a large (50-m3) artificial pond. The transport rate across the water/air interface during the day exceeded the rate at night and was positively correlated to air temperature. Volatilization is probably responsible for the PCB transfer.
Statistical classification of the toxicity and polynuclear aromatic hydrocarbon contamination of sediments from a highly industrialized seaport
Authors: Alden Raymond W. , Butt Arthur J.
Published: March 2010

Data from a comprehensive series of toxicity bioassays and chemical surveys were analyzed by discriminant analysis to statistically classify sediment quality in the Port of Hampton Roads, Virginia. A consensus “map” indicating sediment quality was developed to classify stations into “clean” vs. “contaminated” groups. The “clean” group, which produced few biological effects, included stations with low levels of polynuclear aromatic hydrocarbons (PAHs), while significant biological effects were associated with “contaminated” sediments containing high levels of PAHs. The statistical analysis clearly indicated different characteristic patterns of PAHs in the various geographic regions. Both the toxicological and PAH data indicated a change in the sediment quality between dredging operations. The multivariate statistical approach to the classification of sediment quality has been shown to provide an effective, objective means of evaluating dredged materials being considered for ocean disposal.
Serum sorbitol dehydrogenase activity as an indicator of chemically induced liver damage in rainbow trout
Authors: Dixon D. G. , Hodson P. V. , Kaiser K. L. E.
Published: March 2010

The utility of serum sorbitol dehydrogenase activity (SSDH) to diagnose chemically induced liver damage in fish was assessed with rainbow trout. The assay was both precise and repeatable and was unaffected by long-term sample storage in liquid nitrogen, by fish weight, by sex, or by fasting. Exposure of trout to phenol, p-chlorophenol, p-phenoxyphenol, carbon tetrachloride, or copper injected intraperitoneally (i.p.) or added to water, caused an exposure-dependent increase in SSDH activity. Peak activity occurred 48 h after the start of exposure. Cyanide had no effect on SSDH activity, consistent with previous observations of no hepatotoxicity. The response to toxic chemicals was unaffected by impaired liver function induced by preexposure to excessive levels of dietary carbohydrate. Elevated SSDH activity was strongly correlated to decreased serum protein levels. Hepatic lesions visible at the light-microscope level were observed with waterborne toxicant exposure; parenchymatous edema was closely associated with increased liver somatic index (LSI). With i.p. dosing, however, biochemical lesions preceded histopathology since no visible lesions or changes in LSI were associated with toxicant exposure. Therefore, SSDH activity provides a good, reliable indicator of sublethal hepatotoxicity in studies of chemical effects on fish.
Hepatic microsomal mixed-function oxidase activity in the japanese medaka (Oryzias latipes)
Authors: Schell John D. , Cooper Kathryn O. , Cooper Keith R.
Published: March 2010

Growing interest in the use of the Japanese medaka (Oryzias latipes), a small aquarium fish, for carcinogenicity and toxicological studies necessitates an understanding of their xenobiotic metabolizing capabilities. Historically, hepatic mixed-function oxidase activity has been characterized using inducing agents such as beta-naphthoflavone (BNF). Hepatic cytochrome P450, 7-ethoxy-resorufin o-deethylase (EROD) activity, and NADPH-cytochrome c reductase activity were increased in male and female adult medaka following dietary exposure to BNF. In noninduced male and female adult medaka, EROD activity was not detectable. The EROD activity of the male medaka increased to 1.05 nmol/min/mg protein on day 4. Female EROD activity reached a maximum of 0.65 nmol/min/mg protein on day 2. NADPH-cytochrome c reductase activity in the males increased from a control level of 33.02 to 81.9 nmol/min/mg protein by day 4 of BNF exposure. NADPH-cytochrome c reductase activity in females reached a maximum rate of 63.4 nmol/min/mg protein within 48 h of exposure, but returned to noninduced levels (49.6 nmol/min/mg protein) by day 4. Cytochrome P 450 concentration, liver-to-body-weight ratios, and microsomal protein concentration increased in a time-dependent fashion for both sexes following BNF exposure.
A discussion of chemical equilibria and transport at the sediment-water interface
Authors: Reuber Barbara , Mackay Donald , Paterson Sally , Stokes Pamela
Published: March 2010

The kinetic and equilibrium processes influencing the behavior of organic contaminants in the vicinity of the sediment-water interface are discussed. These processes include sorption, sediment deposition and resuspension, diffusive and convective movement of contaminants in pore water, and bioturbation. A series of relatively simple mathematical models is presented to illustrate some expected relationships between water and sediment and biota (fish) concentrations. Some implications of these relationships for chemical behavior and bioavailability in aquatic systems are discussed.
Developmental toxicity of four model alkylating agents on japanese medaka fish (Oryzias latipes) embryos
Authors: Solomon Frances P. , Faustman Elaine M.
Published: March 2010

As public and scientific interest increases in identifying in vitro alternatives to whole-animal testing, there is a need to characterize the responses of in vitro systems to defined chemical agents. In this paper we have utilized the medaka (Oryzias latipes) embryo culture system to examine the developmental toxicity of a series of chemically defined model alkylating agents. The medaka embryo culture system was used because it offers numerous advantages over other in vitro embryo systems. This study has examined the developmental toxicity of four model alkylating agents: methylnitrosourea (MNU), ethylnitrosourea (ENU), methyl methanesulfonate (MMS), and ethyl methanesulfonate (EMS). These alkylating agents represent chemical models for compounds that are environmental and occupational pollutants. The embryotoxic parameters that were monitored include embryolethality and specific malformations. Medaka embryos in early organogenesis (stage 20) were exposed for 2 h to the test compound at concentrations ranging from 0.75 to 120 mM. The embryos were cultured at 20°C in Petri dishes and were assessed daily for viability and gross malformations until hatching. All agents tested produced concentration-dependent decreases in viability and increases in malformations. The developmental toxicity of the four alkylating agents examined is, in order of decreasing potency, MNU > ENU > MMS > EMS. A similar spectrum of malformations was produced following exposure to each alkylating agent; however, agents undergoing first-order nucleophilic substitution reactions were more potent developmental toxins than those agents which undergo second-order nucleophilic substitution reactions. Observed abnormalities included flexure, cardiac, optic, and cephalic malformations.
Reduced lethality of Al, Zn and Cu mixtures to american flagfish by complexation with humic substances in acidified soft waters
Authors: Hutchinson Neil J. , Sprague John B.
Published: March 2010

Acute lethality of Al/Zn/Cu mixtures to fry of American flagfish (Jordanella floridae) was reduced by factors of 2.1 to 14.5 in water of pH 5.8 from four lakes of the Canadian Shield, compared to lethality in synthetic soft water. Test waters ranged from clear to dark brown but were otherwise similar. LC50s for total Al/Zn/Cu were correlated with several measurements of humic substances in the lakes, including total organic carbon (TOC), absorbance at 310 nm (A310), color, and Secchi depth. Dialysis techniques showed that toxicity of Al and Cu was reduced by complexation with high-molecular-weight (MW) (> 1,000) humic substances in the colored water. Zn was present mainly as low-MW forms and effects of complexation on its lethality were not resolved. Regressions predicted that survival of early life-stages of fish is doubtful in acidified, soft-water lakes containing less than 2.2 mg/L of TOC or in which A310 <0.016. Changes in trace-metal lethality associated with TOC were greater than those associated with changes in total hardness.
Aluminum toxicity and speciation in soil liquids—experiments with Allium cepa L
Authors: Berggren Dan , Fiskesjö Geirid
Published: March 2010

Allium cepa L. was grown in soil liquids from beech, birch, and spruce stands of south Sweden. Root growth, cytology, and morphology at different concentrations and speciation of aluminum were studied. A strong cation exchange resin was used to discriminate between toxic and nontoxic species of Al.

Root growth was inhibited in all soil liquids compared to controls and was nonlinearly related to the total Al concentration. Cytological changes (i.e., release of nucleolar material into the cytoplasm) were found in certain root tip cells and appeared over the whole Al concentration range of the soil liquids studied. The ion exchange method investigated was able to discriminate between toxic and nontoxic Al in the soil liquid from the mor layer of a podzol (dissolved organic carbon content = 80 mg/L). Labile Al, predominantly corresponding to inorganic monomeric Al forms, made up the toxic Al fraction.
An evaluation of avian impact assessment techniques following broad-scale forest insecticide sprays
Authors: Mineau Pierre , Peakall David B.
Published: March 2010

We briefly review methods for assessing the impact of forest insecticide spray programs on forest songbirds and discuss the applicabilities of various census techniques. Data obtained on brain acetylcholinesterase enzyme (AChE) levels in live birds collected postspray are reanalyzed. We conclude that these data show a severe collection bias in favor of birds with a low (e.g., approximately below 30% from control) level of AChE inhibition. Possible solutions are discussed. Finally, we suggest that multiyear impact assessment studies involving a number of reproductive parameters are needed to evaluate the effects of nonpersistent insecticides on forest songbirds.
Estimating responses of fish populations to toxic contaminants
Authors: Barnthouse Lawrence W. , Suter Glenn W. , Rosen Aaron E. , Beauchamp John J.
Published: March 2010

In assessments of risks of toxic contaminants to fish populations, the endpoints of ultimate interest are the persistence, abundance, and production of populations. In this article we demonstrate a method for expressing toxicity test data obtained from full-life-cycle tests in terms of the same indices used to assess effects of harvesting and power-plant cooling systems on fish populations. Our approach involves fitting the logistic concentration-response function to chronic test data and coupling the functions obtained to a fish life-cycle model. Confidence bands derived from the data quantify uncertainties inherent in predicting population-level effects from (1) full-life-cycle test data for the species of interest, (2) extrapolation of a concentration-response function from an acute LC50 for the species of interest, and (3) extrapolation from an acute LC50 for another species. Using rainbow trout and largemouth bass as representative species, we evaluate the relative importances of three sources of uncertainty contributing to prediction intervals for populationlevel effects. We also compare population-level concentration-response functions to predicted and experimentally derived maximum acceptable toxicant concentrations for five toxic chemicals.
Behavior of mallard ducklings from adults exposed to selenium
Authors: Heinz Gary H. , Gold Lyn G.
Published: March 2010

Pairs of adult mallards (Anas platyrhynchos) were fed a control diet or a diet containing 1, 2, 4 or 8 ppm selenium in the form of seleno-DL-methionine. Ducklings from these pairs were fed an untreated diet from hatching through 6 d of age, at which time their avoidance of a fright stimulus was tested. Selenium had no effect on the ducklings' response to the fright stimulus.
Seawater challenge testing of coho salmon smolts following exposure to roundup® herbicide
Authors: Mitchell David G. , Chapman Peter M. , Long Timothy J.
Published: March 2010

Concentrations of Roundup® herbicide of up to 10 times those encountered in the environment immediately after aerial application (2.78 mg/L) did not affect 24–h seawater survival; nor did plasma sodium concentration, hematocrit or growth in 10-d exposures with yearling coho salmon (Oncorhynchus kisutch). Similarly, no abnormal responses were noted when a 10-d freshwater recovery period was provided between the herbicide and seawater exposures. These results indicate that the application of Roundup at the manufacturer's recommended use-rates for forestry management will not adversely affect the ability of coho salmon smolts to adapt to seawater and to osmoregulate normally.
Effects of hardness, alkalinity and pH on the toxicity of pentachlorophenol to selenastrum capricornutum (printz)
Authors: Smith P. D. , Brockway D. L. , Stancil F. E.
Published: March 2010

The toxicity of pentachlorophenol (PCP) to Selenastrum capricornutum was examined in three different culture media: a hard and a soft form of Freeman's reference water and the algal assay bottle test (AABT) medium (a soft water). The 96-h growth potentials of the media were equal (28–29 mg/L dry wt.) but 96-h EC50s ranged sevenfold: 0.11 mg/L (AABT), 0.15 mg/L (Freeman's soft water) and 0.76 mg/L (Freeman's hard water). Culture media equilibrium pH and 96-h EC50 were strongly correlated (r = 1.00). Evidence is presented that supports the hypothesis that the toxicity of PCP, a weak acid, is due primarily to the concentration of the undissociated species.
Acute bioassays and hazard evaluation of representative contaminants detected in great lakes fish
Authors: Passino Dora R. May , Smith Stephen B.
Published: March 2010

We have provided a hazard ranking for 19 classes of compounds representing many of the nearly 500 organic compounds identified by gas chromatography-mass spectrometry in lake trout (Salvelinus namaycush) and walleye (Stizostedion vitreum vitreum) from the Great Lakes and Lake St. Clair. We initially made a provisional hazard ranking based on available published and unpublished information on aquatic toxicity, bioaccumulation, occurrence and sources. Acute toxicity tests with Daphnia pulex at 17°C in reconstituted hard water were performed with 30 compounds representative of the 19 classes that were highest in the provisional ranking. The resulting toxicity data, along with information on the compounds' occurrence in Great Lakes fish and their sources, were ranked and weighted and then used in calculating the revised hazard ranking. The 10 most hazardous classes, in descending order, are as follows (values shown are mean 48-h EC50s, in μg/ml): arene halides (e.g., polychlorinated biphenyls, DDT), 0.0011; phthalate esters, 0.133; chlorinated camphenes (toxaphene), 0.0082; polyaromatic hydrocarbons (PAHs; e.g., dimethyl-naphthalene) and reduced derivatives, 1.01; chlorinated fused polycyclics (e.g., trwzs-nonachlor), 0.022; nitrogen-containing compounds (e.g., O-methylhydroxyl-amine), 1.35; alkyl halides (e.g., (bromomethyl)cyclohexene), 10.1; cyclic alkanes (e.g., cyclododecane), 20.9; silicon-containing compounds (e.g., dimethyldiethoxy silane), 1.25; and heterocyclic nitrogen compounds (e.g., nicotine), 2.48. We recommend that chronic bioassays be conducted with fish and invertebrates to determine the sublethal effects of the following classes of compounds, for which few toxicity data are available: PAHs, heterocyclic nitrogen compounds, other nitrogen-containing compounds, alkyl halides, cyclic alkanes and silicon-containing compounds. Information from these types of studies will aid researchers in determining the possible causal role these contaminants play in the decline and reproductive impairment of Great Lakes fish.
Chromate ion as a reference toxicant for aquatic phytotoxicity tests
Authors: Wang Wuncheng
Published: March 2010

To conduct toxicity tests, it is essential to include controls to ascertain the health of the test organisms. The common practice is to include negative controls in every test. That positive controls are not used is perhaps because there is no consensus about the reference toxicant. The objective of this study was to test chromate ion as a candidate for reference toxicant. Two aquatic phytotoxicity tests were performed: a millet root elongation test and a duckweed test.

To the same test species, the Cr(VI) toxic effect was very consistent in repeated experiments. The toxic effects to millet were nearly identical in both deionized water and sewage effluent samples. The toxic effect to duckweed was also highly repeatable in 59 water samples from 18 sample stations. The results suggest that the Cr(VI) ion can be used as a general reference toxicant in river water, lake water or wastewater samples. The concentration-effect relationships, however, are different, depending on the test organisms.
Toxicity of nickel to common duckweed (Lemna minor)
Authors: Wang Wuncheng
Published: March 2010

The nickel concentration of 1.0 mg/L in total form has been adopted as the indigenous aquatic life standard. The objective of this study was to test nickel toxicity to duckweed in water samples encompassing a wide variety of water quality. Fifty-nine samples were collected from 18 stations: 10 in Illinois and 8 in neighboring states. Common duckweed, Lemna minor, was exposed to nickel for 96 h. Nickel exhibited the highest phytotoxicity to duckweed in water from the Hayes Creek and Horseshoe Lake stations, the two stations where water contained the lowest hardness, 37 to 78 mg/L as CaCO3. The IC50s for nickel were 0.36 and 0.21 mg/L, respectively. The other 16 stations, combined, showed a mean and standard deviation of 2.5 ± 0.83 mg/L. It is estimated that the nickel ion at a concentration of 1 mg/L can cause a 30% inhibition of duckweed growth in almost all surface waters, and a 70% inhibition in extremely soft waters.
Environmental impact of an aviation kerosene spill on stream water quality in cambria county, Pennsylvania
Authors: Guiney Patrick D. , Sykora Jan L. , Keleti George
Published: March 2010

A comprehensive survey of a small Cambria County, Pennsylvania, watershed contaminated by a British Petroleum aviation kerosene leak was conducted from 9 November 1982 until 20 December 1983. The biological data showed evidence of a rapid recolonization process by benthic macroinvertebrates that began at the last two downstream stations shortly after the spill. The recovery at stations located immediately below the spill was delayed because few organisms for repopulation were present in the clean, upstream section and because a drought eliminated most of the biota in the immediate headwaters during 1983. Measurements of species diversity of benthic invertebrates showed that most of the stations in the contaminated sections recovered between June and October 1983. Short-term in situ toxicity bioassays conducted with brook trout in April 1983 showed that the stream was again suitable for restocking with trout. In addition, a fish electroshocking program in May and October 1983 clearly demonstrated that the contaminated sections of the stream had recovered and again supported a diverse fish population, including trout and young-of-the-year minnows and sunfish. The results of chemical analyses and biochemical oxygen demand measurements indicated that the water quality in the contaminated section recovered between 30 November and 14 December 1982.

The major factors that accelerated the recolonization process in the contaminated watershed were (a) immediate and effective cleanup activities; (b) a plentiful source of unpolluted dilution water; (c) the drift of benthic organisms available for recolonization; and (d) the immigration of fish from the unpolluted sections of the watershed.
Microbial activity in soils contaminated with 2,3,7,8-TCDD
Authors: Arthur Mickey F. , Frea James I.
Published: March 2010

Soils from Times Beach, Missouri, containing from 8 ng g−1 to 2.4 μg g−1 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were examined for microbial activity. Parameters included enumeration of aerobic eutrophic and oligotrophic bacteria, fungi, and actinomycetes; enzymatic assays, including assays for dehydrogenase, arylsulfatase, rhodanese, and acid and alkaline phosphatases; and soil respiration (CO2 evolution). The soils were also characterized for organic matter content, specific surface area, cation exchange capacity, pH, electrical conductivity, bulk density, particle size, and solvent-extractable content. Compared with control soils, the TCDD-contaminated soils showed considerable microbial activity and diversity, suggesting that TCDD is not microbially toxic at these concentrations and/or is not bioavailable.
Biodegradation of three azaarene congeners in river water
Authors: Cassidy Richard A. , Birge Wesley J. , Black Jeffrey A.
Published: March 2010

The biodegradability of three structurally related azaarenes (pyridine, quinoline, and acridine) at various concentrations (which gave 0 to 100% lethality to embryo-larval stages of an indigenous frog species) was determined using a river water die-away test and water collected from the Green River (Newton, KY). HPLC analyses of the amended river water during the 6- to 11-d study revealed rapid removal of pyridine and quinoline at the lower substrate concentrations; however, no change in the acridine concentrations was detected during the 11-d study. Except for the lowest quinoline concentration, the turnover times and latent periods for pyridine and quinoline increased with higher initial concentrations, but the kinetics of microbial oxidation were constant at all but the highest concentrations. The adaptation of previously exposed river flora was determined by respiking degraded waters. When the flora were reexposed to the substrates there was no latent period and the kinetics were superimposable. By tracking the metabolites of quinoline, sequential oxidation of the parent compound to more polar species was demonstrated. It was determined by co-culturing quinoline and acridine that acridine nondegradability was not due to any inhibitory effect that acridine may have on the river flora.
Prediction of consumer product chemical concentrations as a function of publicly owned treatment works treatment type and riverine dilution
Authors: Rapaport Robert A.
Published: March 2010

In the United States, effluent from publicly owned treatment works (POTW) becomes diluted in surface waters. These initial concentrations of chemicals in rivers below the effluent outfalls are used as conservative estimates of downstream concentrations. Using computerized U.S. Environmental Protection Agency databases, which include POTW flow rates and receiving water stream flows, dilution factors were determined for activated sludge, trickling filter, and primary treatments as a function of total U.S. POTW discharge and the total number of POTW. Curves were constructed and mathematical functions fitted for POTW flow and number versus dilution factor for each of the treatment types. Using a computer program in which these curves are applied, the fraction of total POTW flow discharged to U.S. rivers and streams that will have a concentration greater than any specified value (e.g., water quality criteria) can be predicted. This procedure will be useful in safety assessments of chemicals discharged to natural waters as components of POTW effluent.
Preparation of aqueous solutions of sparingly soluble organic substances: II. Multicomponent systems — hydrocarbon mixtures and petroleum products
Authors: Shiu Wan Ying , Maijanen Aila , Ng Anita L. Y. , Mackay Donald
Published: March 2010

The theory underlying the dissolution of mixtures of sparingly soluble organic chemicals, such as crude oils, in water is outlined, showing that the “solubility” of mixtures is a function of both the composition of the organic mixture and the ratio of water to organic phase volumes. A generator column method of preparing solutions of petroleum mixtures is described, the results obtained being consistent with the theory. The implications of these findings for studies of the composition and toxicity of aqueous solutions of organic mixtures are discussed.
Influence of sorbent concentration on sorption of kepone to solids
Authors: Staples Charles A. , Geiselmann Stephanie J.
Published: March 2010

Solids concentrations in environmental compartments may vary from a few milligrams per liter in surface waters to 500,000 mg/L in sediments and subsurface ground waters. The effect of solids concentration (both with and without particle-bound organic matter) on kepone soil/water partition coefficients was investigated. A strong dependency on particle concentration was found at concentrations of 100 mg/L and above. A weaker dependency on organic carbon was found at these solids concentrations. Standard empirical relationships for sorption of organic chemicals based solely on particle organic carbon content are not applicable for the solids-dependent relationship found here for kepone. These data indicate that new relationships based on both particle characteristics and organic carbon content are required to predict absorption and desorption in environments high in solids and low in organic carbon, such as subsurface ground water.
Low chemical concentration and pH as factors limiting the success of inoculation to enhance biodegradation
Authors: Zaidi Baqar R. , Stucki Gerhard , Alexander Martin
Published: March 2010

A strain of Pseudomonas that mineralized 1 microgram of p-nitrophenol (PNP) per milliliter in culture failed to mineralize the compound in nonsterile or sterile lake water. The bacterium did not act on PNP at the pH of the lake water (pH 8.0) or in culture medium at the same pH, although it did mineralize PNP when added to sterile lake water samples adjusted to pH 7.0. A second strain of Pseudomonas that grew and mineralized 1 μg PNP/ml in culture at pH 8.0 and in sterile lake water at pH 7.0 neither mineralized nor grew on PNP in sterile lake water at pH 8.0. A third strain of Pseudomonas grew on and mineralized 1 μg PNP/ml in sterile lake water at pH 8.0 but failed to enhance mineralization when added to nonsterile lake water at that pH. Corynebacterium sp. grew on and mineralized 1 μg PNP/ml in culture medium and in sterile lake water, and its inoculation into nonsterile lake water greatly reduced the time for the mineralization of 1.0 and 0.1 μg PNP/ml. The inoculation of nonsterile lake water with Corynebacterium sp., which mineralized 26 and 17 ng PNP/ml in culture, resulted in a biphasic transformation of 26 and 16 ng PNP/ml. Only the initial phase was more rapid than in uninoculated lake water. Inoculation of Corynebacterium sp. into sewage markedly shortened the time for extensive mineralization of 100 ng but not of 26 and 16 ng PNP/ml. We suggest that microorganisms that are able to degrade chemicals in culture may not do so when introduced into natural environments because of unfavorable pH or the organisms' inability to readily use compounds that are present at low concentrations.
Evaluation of the relative sensitivities of 7-D Daphnia magna and Ceriodaphnia dubia toxicity tests for cadmium and sodium pentachlorophenate
Authors: Winner Robert W.
Published: March 2010

A comparison of the results of 7-d Daphnia magna and Ceriodaphnia dubia toxicity tests indicated that the two species were equally sensitive to sodium pentachlorophenate (PCP) but that C. dubia was more sensitive to cadmium. The most sensitive chronic endpoint varied with species and test chemical. The most sensitive index of cadmium stress in D. magna was body length of primiparous females, whereas in C. dubia it was total young produced per female. For both D. magna and C. dubia, reproductive indices were more sensitive indicators of PCP stress than was survival. The results of this study, along with data from the literature, suggest that C. dubia is as, or more, sensitive to inorganic and organic chemicals than is D. magna, and that, if the indices of toxicity are carefully chosen, 7-d tests may provide estimates of no-effect concentrations that are as low as those generated in tests of longer duration.
Structure-activity relationships of species-selectivity in acute chemical toxicity between fish and rodents
Authors: Wallace Kendall B. , Niemi Gerald J.
Published: March 2010

Although regression analyses between the acute oral or intraperitoneal LD50 values for both rats (Rattus norvegicus) and mice (Mus musculus) and the 96-h LC50 values for fathead minnows (Pimephales promelas) or rainbow trout (Salmo gairdneri) for a broad spectrum of environmental chemicals were statistically significant, the large variability in the regressions limits their practical utility for interspecies extrapolations. To gain a better understanding of this variability, analyses were performed to reveal the structural features characteristic of those chemicals that deviate substantially from the interspecies regressions. The criterion selected to indicate excessive variability was a greater-than-fourfold difference between the observed rodent LD50 and that estimated from the regression against the fish data. Discriminant function analyses showed aldehydes, esters and organophosphorus insecticides to be the primary outliers in the fish-to-rodent comparisons. Rodents were generally less sensitive to intoxication with carbonyl-containing compounds but more sensitive to organophosphate anticholinesterase poisoning than were fish. This species-selectivity for both classes of chemicals correlates with species-related differences in metabolic clearance and/or pharmacodynamic differences in target organ sensitivities. Since these same idiosyncracies in metabolic disposition and receptor sensitivity would be suspected to be operative for structurally related chemical compounds, interspecies extrapolations of toxicity information for both carbonyl compounds and for anticholinesterase agents should take into consideration these important factors, which confer certain degrees of species-selectivity for these chemical classes.