bluuebunny/crossref_metadata_2025 huggingface dataset:
Residue dynamics and effects of aluminum on growth and mortality in brook trout
Authors: Cleveland Laverne , Buckler Denny R. , Brumbaugh William G.
Published: March 2010

Brook trout (Salvelinus fontinalis) about 30 d old and weighing 0.2 g were exposed for 56 d to duplicated nominal pHs of 5.0, 6.0 and 7.2 in combination with nominal aluminum concentrations of 200 μ/L. At 56 d, each treatment group was transferred to water of the same pH without added aluminum and held for 28 d of depuration. Samples of fish were collected from each treatment for whole-body aluminum analyses on days 3, 7, 14, 28 and 56 of the exposure. During the depuration period, fish were sampled at 3, 7, 14 and 28 d for whole-body aluminum analyses. Mortality and pH were monitored daily in each treatment. The estimated time to 90% steady state for aluminum in the fish was 1.5 d at pH 5.3, 4.2 d at pH 6.1 and 1.7 d at pH 7.2. Estimated steady-state bioconcentration factors for aluminum, which were inversely related to pH, were 215 at pH 5.3, 123 at pH 6.1 and 36 at pH 7.2. The maximum observed factors were 232 at pH 5.3, 153 at pH 6.1 and 46 at pH 7.2. Brook trout eliminated aluminum from tissues more rapidly at pH 5.3 than at pH 6.1 and 7.2. Mortality was generally higher in brook trout exposed to aluminum at pH 5.3 than in those exposed at pH 6.1 and 7.2. Mortality was lowest (<3%) for the fish exposed to aluminum at pH 7.2.
Modeling ceriodaphnia toxicity in the Naugatuck river II. Copper, hardness and effluent interactions
Authors: Di Toro Dominic M. , Hallden James A. , Plafkini James L.
Published: March 2010

Previous studies have shown that whole toxicity in the Naugatuck River, Connecticut, does not exhibit additive behavior. The nature of whole toxicity in the river is reassessed using available water chemistry data to identify the primary toxicants and quantify their interactions in the river. Two major classes of toxicity—copper from industrial discharges and toxicity from publicly owned treatments works (POTWs)—are identified. A water quality model of whole toxicity is constructed, based on the analysis of specific toxicant data. The results are in closer agreement with observed instream toxicity than the previous model which assumed strict additivity of effluent toxicity.
Abiotic and biotic factors influencing in situ trace metal levels in macroinvertebrates in freshwater ecosystems
Authors: van Hattum Bert , Timmermans Klaas R. , Govers Harrie A.
Published: March 2010

We examined the potential of a multiple regression model, including both biotic and abiotic variables, to predict trace metal levels (Cd, Pb, Cu and Zn) in benthic invertebrate communities from various aquatic habitats in The Netherlands. Variables included in the regression model and their relative contribution to the predictive power appeared to be highly element-specific. Sediment- and water-related abiotic variables were especially important for the prediction of Cd, Pb and, to a lesser extent, Zn. For the essential trace metals, the biotic variables such as the presence of hemocyanin (in the case of Cu) and trophic level (Zn) appeared to have a dominant influence. Species-body weight showed a negative log-linear relationship with trace metal levels of Pb and, to a lesser extent, Cu and Cd. For all metals, significant coefficients of multiple correlation were observed. The variance in invertebrate trace metal levels explained by the model ranged from 25% for Zn to 37% for Cd and Cu. For all trace metals, the introduction of biotic variables resulted in a significant increase in predictive power (p < 0.02), compared to the use of only abiotic predictors. Marked differences in predictive power of the model were observed among various species or taxonomic categories. For several species remarkably significant relationships were revealed, indicating the potential usefulness of the organisms for biological monitoring and further modeling studies.
Cyclic peptide hepatotoxins from freshwater cyanobacterial (blue-green algae) waterblooms collected in Central China
Authors: Zhang Qing-Xue , Yu Min-Juan , Li Shang-Hao , Carmichael Wayne W.
Published: March 2010

Toxic cyanobacteria (blue-green algae) waterblooms have been found in several Chinese water bodies since studies began there in 1984. Waterbloom samples for this study contained Anabaena circinalis, Microcystis aeruginosa and Oscillatoria sp. Only those waterblooms dominated by Microcystis aeruginosa were toxic by the intraperitoneal (i.p.) mouse bioassay. Signs of poisoning were the same as with known hepatotoxic cyclic peptide microcystins. One toxic fraction was isolated from each Microcystis aeruginosa sample. Two hepatotoxic peptides were purified from each of the fractions by high-performance liquid chromatography and identified by amino acid analysis followed by low and high resolution fast-atom bombardment mass spectrometry (FAB-MS). LD50 i.p. mouse values for the two toxins were 245 μg/kg (Toxin A) and 53 μg/g (Toxin B). Toxin content in the cells was 0.03 to 3.95 mg/g (Toxin A) and 0.18 to 3.33 mg/kg (Toxin B). The amino acid composition of Toxin A was alanine [1], arginine [2], glutamic acid [1] and β-methylaspartic acid [1]; for Toxin B it was the same, except one of the arginines was replaced with a leucine. Low- and high-resolution FAB-MS showed that the molecular weights were 1,037 m/z (Toxin A) and 994 m/z (Toxin B), with formulas of C49H76O12N13 (Toxin A) and C49H75O12N10 (Toxin B). It was concluded that Toxin A is microcystin-RR and Toxin B is microcystin-LR, both known cyclic heptapeptide hepatotoxins isolated from cyanobacteria in other parts of the world. Sodium borohydride reduction of microcystin-RR yielded dihydro-microcystin-RR (m/z = 1,039), an important intermediate in the preparation of tritium-labeled toxin for metabolism and fate studies.
Structure-activity relationships of chlorobenzenes using DNA measurement as a toxicity parameter in algae
Authors: Figueroa Ines Del C. , Simmons Milagros S.
Published: March 2010

This study investigated the effects of chlorobenzenes on the diatom Cyclotella meneghiniana using DNA measurement as a toxicity parameter and related toxicity to different physicochemical properties of chlorobenzenes. The organisms were exposed to chlorobenzene solutions for 48 h to obtain effective concentration (EC50) values (in terms of percent DNA reduction). The toxicity (EC50) increased with increasing degree of chlorination, as follows: monochlorobenzene (235.74 mg/L), dichlorobenzenes (23.33-51.88 mg/L), trichlorobenzenes (0.59-6.42 mg/L), tetra-chlorobenzenes (0.27-1.39 mg/L), pentachlorobenzene (0.008 mg/L) and hexachlorobenzene (0.002 mg/L). Quantitative structure-activity relationships were developed showing high correlations, as follows: water solubility (r2 = 0.96); molecular volume (r2 = 0.92); zero-order connectivity index (r2 = 0.92); second-order connectivity index (r2 = 0.92); molecular surface area (r2 = 0.92); octanol/water partition coefficient (r2 = 0.86); bioconcentration factor (r2 = 0.86); and inorganic/organic character (r2 = 0.83). A poor correlation, however, was obtained with the molecular negentropy index (r2 = 0.25). The toxic effect (EC50) was explained in terms of a partitioning process as a function of the aqueous solubility of the chlorobenzenes and was found to occur at similar degrees of exposure saturation.
Cadmium turnover in minnows (phoxinus phoxinus) preexposed to waterborne cadmium
Authors: Glynn Anders Wicklund , Olsson Per-Erik
Published: March 2010

The radioactive isotope 109Cd was used to study the turnover of Cd in minnows (Phoxinus phoxinus) preexposed to waterborne Cd. Three groups of fish were preexposed to 3 nM Cd for 0, 30 and 91 d before a 24-h 109Cd exposure (3 nM Cd). The effect of preexposure on the turnover of 109Cd in the fish was studied during a 64-d post-tracer exposure period at 3 nM Cd. The major effect of Cd preexposure on the 109Cd turnover was a decreased uptake of 109Cd into the gills. In the gill tissue, the 109Cd was retained by Cd binding ligands mainly in the cytosolic fraction. Preexposure decreased the percentage of 109Cd retained in a cytosolic high-molecular-weight fraction at the end of the tracer exposure. At the same time, an increased percentage of tracer was retained in a low-molecular-weight cytosolic fraction with high 109Cd content (Cd-BP), probably metallothionein (MT). This effect was not caused by an increased MT content in the preexposed fish. The liver, kidney, muscle and bone accumulated 109Cd, while the gills, head and skin eliminated tracer during the 64-d post-tracer exposure period. The 109Cd elimination and accumulation were not altered by the Cd preexposure. A large part of the tracer accumulated in the liver and kidney was detected in the Cd-BP fraction, and the MT content in the organs was not altered by the preexposure.
Fate and acute toxicity of bromoxynil esters in an experimental prairie wetland
Authors: Muir D. C. G. , Kenny D. F. , Grift N. P. , Robinson R. D. , Titman R. D. , Murkin H. R.
Published: March 2010

The partitioning, degradation and toxicity of a single spray application of a 1:1 mixture of bromoxynil octanoate (BO) and bromoxynil butyrate (BB) were studied in fifteen 0.01-ha ponds located in the Delta marsh area of Manitoba. Intensive sarnpling of two ponds treated at 2.5 μg/L and two treated at 50 μg/L (nominal concentrations) showed that BO and BB persisted in the surface microlayer (0–1 mm) of the water at levels 50- to 100-fold higher than the intended treatment level, with half-lives of 0.8 to 2.5 h. In subsurface waters (10–20 cm depth) the major forms of the herbicide were bromoxynil-phenol and its monobromo- analog (3-bromo-4-hydroxybenzonitrile; MBBP). Half-lives of the phenol averaged 9.2 d in ponds treated at 50 μg/L and 14.5 d in those receiving 2.5 μg/L. Low ng/g (dry wt.) levels of BO, BB, MBBP and bromoxynil-phenol were present in bottom sediments (0–2 cm depth) during the first 15 d posttreatment and declined to near detection limits (<0.5 ng/g) by 120 d after spray application. Complete mortality of brook sticklebacks (Culaea inconstans), held in cages in subsurface waters, occurred within 24 h at the two highest treatment levels (nominal concentrations of 100 and 500 μg/L). Mortality of caged Hyalella azteca at the highest dose levels ranged from 85 to 95% at 50 h.
Effects of photoenhanced toxicity of anthracene on ecological and genetic fitness of daphnia magna: A reappraisal
Authors: Foran Jeffery A. , Holst Linda L. , Giesy John P.
Published: March 2010

Holst and Giesy [1] reported photoenhanced effects of anthracene exposure on reproduction of Daphnia magna in terms of total clutch size and survival over a 21-d period. A reappraisal of those experiments, using additional data regarding time to first brood, average size of first brood and the intrinsic rate of increase, rm, for exposures with and without anthracene and/or ultraviolet radiation (UVR), reveals that inferred impacts on genetic fitness as exemplified by rm are significant only for the highest exposure tested, whereas ecological fitness, measured by the time to first brood, was unimpaired at any combination of UVR and anthracene.
Humic acid-modified silica as a model aquifer material
Authors: Burris David R. , Antworth Christopher P. , Stauffer Thomas B. , MacIntyre William G.
Published: March 2010

The sorption behavior of nonionic organic chemicals on humic acid-modified silica was examined to assess its possible use as a simplified model of natural low organic carbon aquifer materials. Column and batch sorption experiments were conducted on humic acid-coated silica (0.073% organic carbon), using tetrachloroethylene (PCE) and 1-methylnaphthalene (MN). Batch kinetic experiments showed that equilibrium was attained rapidly for PCE (˜1 d), whereas several tens of days were required for MN. Batch experiment results indicated Freundlich (nonlinear) isotherm behavior when a wide concentration range was examined. Sorption coefficients derived from the column experiments were consistent with the batch-derived Freundlich isotherms, illustrating the importance of isotherm type on breakthrough curves and solute transport in ground water. Similarities exist between the sorption behavior observed in this study and that of a number of natural aquifer materials. Humic acid-modified silica serves as a simplified model for aquifer materials, which tend to be more complex and difficult to characterize and can be used to examine organic solute transport processes in ground water.
Effects of alachlor and metolachlor on the biological activity of Azospirillum brasilense grown in chemically defined and dialyzed-soil media
Authors: Salmeron Victor , Martinez-Toledo Maria V. , Gonzalez-Lopez J.
Published: March 2010

The effects of 100, 300 and 500 μg/ml of alachlor and metolachlor were investigated in cells of Azospirillum brasilense grown in chemically defined medium and dialyzed-soil medium. Microorganisms cultured in the presence of alachlor showed lower nitrogenase activity and lower levels of ATP compared with control cells. However, the effects due to metolachlor disappeared after 48 h, showing that Azospirillum brasilense can tolerate high concentrations of that herbicide.
Toxicity tests of effluents with marsh plants in water and sediment
Authors: Walsh Gerald E. , Weber David E. , Simon Tasha L. , Brashers Linda K.
Published: March 2010

Methods are described for toxicity testing of water and sediment with two varieties of the freshwater marsh plant Echinochloa crusgalli (Linneaus) Palisot de Beauvois (Poaceae), and complex effluents. Two tests are described: a seed germination and early seedling growth test in water, and a survival and seedling growth test in natural and synthetic sediments. Effects of effluents from a sewage treatment plant, tannery, textile mill, pulp and paper mill, coking plant and sewage treatment plant included inhibition of germination, chlorophyll synthesis and growth. The tests with rooted marsh plants were sensitive to pollutants and detected toxicity of a range of pollutants in water and sediment. Synthetic sediments similar to natural sediments allowed toxicity tests to be done under carefully controlled conditions of particle size distribution, organic content, pH, electrode potential (Eh) and cation exchange capacity (CEC).
Effects of methyl parathion on northern bobwhite survivability
Authors: Buerger Theodore T. , Kendall Ronald J. , Mueller Brad S. , Devos Theodore , Williams Bill A.
Published: March 2010

The effects of methyl parathion on survivability of wild northern bobwhites (Colinus virginianus) were investigated from 1986 to 1988 near Tallahassee, Florida. In three field seasons, 197 bobwhites were administered 0, 2, 4 or 6 mg/kg methyl parathion in corn oil by oral intubation, released and monitored for 14 d using radio telemetry. Bobwhites receiving 6 mg/kg methyl parathion had lower survival (P = 0.022) than control birds due to predation, not overt toxicity. There were no differences (P > 0.05) among treatment groups in activity, but methyl parathion may have influenced covey integrity. Birds that survived methyl parathion treatment had brain cholinesterase activities similar to those of control bobwhites. The results suggest that if bobwhites receive sufficiently high methyl parathion exposure in their natural habitats, then their susceptibility to predation may increase.
Bioassays for the toxicity of petroleum oils in chicken embryos
Authors: Couillard Catherine M. , Leighton Frederick A.
Published: March 2010

Applications of 1 μl to 30 μl of six different petroleum oils were made to the shell of fertile leghorn chicken eggs on day 9 of incubation. Mortality and grossly visible morphological changes in the embryos were evaluated 4 d after treatment. South Louisiana crude oil and fuel oil No. 2 were the less toxic of the oils tested, with LD25s of 14.1 and 8.5 μl/egg. The LD25s of Arabian Light, Federated, Norman Wells and Prudhoe Bay crude oils ranged from 3.6 to 4.4 μl/egg. Liver necrosis and edema were found in embryos exposed to the six petroleum oils, suggesting a common mechanism of toxic action. The similarity in mechanism of action was also supported by the similarity of the slopes of the dose-response lines. The use of liver necrosis as an end point for bioassays of oil toxicity was evaluated. The ED25s ranged from 3.6 μl/egg for Federated crude oil to 23.0 μl/egg for fuel oil No. 2. Estimates of the ED25 for liver necrosis could discriminate among the toxicity of the six oils better than could estimates of the LD25 test. There was a good correlation between the two calculations. The ED25 was more reliable and consistent than the LD25 test when bioassays were repeated several times with the same oil.
Leaching potential and decomposition of clopyralid in Swedish soils under field conditions
Authors: Bergström L. , McGibbon A. , Day S. , Snel M.
Published: March 2010

The mobility and decomposition of the herbicide clopyralid (3,6-dichloro-2-pyridinecar-boxylic acid) were studied under field conditions in a sandy soil and a clay soil. Leachate was collected in lysimeters with undisturbed soil (sand) and in tile-drained plots (clay). Soil samples were also collected down to 1 m depth in both soils to characterize the temporal depth distribution of clopyralid in the profiles. The herbicide was applied at two rates, i.e., 120 and 240 g acid equivalents (a.e.)/ha, representing normal and double doses of the compound for sugar beets and oilseed rape. Some lysimeters received supplementary watering. Concentrations of clopyralid above the detection limit {0.4μg/L}, i.e., 0.5 (normal dose) and 6 μg/L (double dose) were found in only two drainage samples from the clay soil. Both samples were collected simultaneously approximately two months after the herbicide application, by which time less than 1 mm of drainage had been collected. The overwhelming part of applied clopyralid remained in the topsoil at both sites. Four months after spraying, no clopyralid was detectable (<2 μg/kg dry soil) in the soil.
Mobility and dissipation studies of metribuzin, atrazine and their metabolites in plainfield sand using field lysimeters
Authors: Bowman Bruce T.
Published: March 2010

Mobility and persistence of metribuzin (Lexone DF) and its metabolites (deaminated, DA; diketo, DK; deaminated-diketo, DADK) were studied using 75-cm × 15-cm field lysimeters packed with Plainfield sand, and subjected to two moisture regimes (rainfall, supplementary watering). Atrazine was applied to all lysimeters as an internal reference. Each lysimeter set consisted of 24 lysimeters, divided into two moisture treatments of six pairs each. Effluent was monitored for metribuzin, DA, DK, DADK, atrazine and desethylatrazine. Selected core pairs were sectioned (7 × 10 cm) and analyzed to determine mobility and persistence for each chemical at weeks 1, 2, 4, 8, 12, and 21. No chemicals moved more than 30 cm, nor were they detected in the effluent of cores receiving rainfall. In cores receiving supplementary watering, substantial amounts of metribuzin moved more than 30 cm by week 2 and eluted on 21 occasions throughout the study. The DADK and DK were much more mobile than metribuzin in the lysimeters, eluting more frequently than metribuzin. Metribuzin and metabolites were considerably more mobile than either atrazine or desethylatrazine in Plainfield sand. Metribuzin disappearance closely followed first-order kinetics with t1/2 values of 3.08 and 2.04 weeks, respectively, for the rainfall and supplementary watering treatments. The primary degradation pathway for metribuzin was through the DK intermediate rather than the DA intermediate.
A strategy for ranking environmentally occurring chemicals. Part V: The development of two genotoxicity QSARs for halogenated aliphatics
Authors: Eriksson Lennart , Jonsson Jörgen , Hellberg Sven , Lindgren Fredrik , Sjöström Michael , Wold Svante , Sandström Björn E. , Svensson Indra
Published: March 2010

A strategy for systematic analysis and priority ranking of chemicals was applied to a class of 58 saturated halogenated aliphatics. The training set, selected by statistical design, was subjected to biological testing in an assay (the DNA precipitation assay) estimating DNA damage in V79 Chinese hamster cells. The obtained genotoxicity data were modeled by construction of two multivariate quantitative structure-activity relationships (QSARs). To experimentally validate the two derived QSAR models, a validation set of chemicals was chosen (also according to statistical design). Predictions were made for the validation set compounds, and they were found to compare well with the observed data. Thus, the two QSARs were utilized to predict the genotoxicity of 36 nontested compounds belonging to the examined class. In addition, it was found that the genotoxicity data required a multitude of chemical and structural descriptors in order to be modelable, and that log P in particular was an informative descriptor variable.
Aqueous solubility of liquid hydrocarbon mixtures containing dissolved solid components
Authors: Vadas George G. , MacIntyre William G. , Burris David R.
Published: March 2010

Two hypothetical supercooled liquid (HSL) solubility estimation methods are evaluated for 11 solid polynuclear aromatic hydrocarbons (PAHs). The HSL solubility is required to estimate the aqueous solubility of solids such as PAHs when they are part of a liquid hydrocarbon mixture. Aqueous solubility experimental data for binary and multicomponent liquid hydrocarbon mixtures containing PAHs were used to evaluate the HSL solubility estimation methods. An HSL solubility estimation method requiring only the component's pure compound solubility and melting point proved to be adequate for most environmental applications.
Predicting chemical accumulation in shoots of aquatic plants
Authors: Wolf Sue D. , Wooten Steven E. , Lassiter Ray R.
Published: March 2010

Chemical exchange dynamics expected for diffusive transfer of a chemical between aqueous solution and plant shoots, and expected bioconcentration based on partitioning properties of the chemical, are explored by using a three—compartment model. The model utilizes three dynamic compartments-leaves, stems, and aqueous exposure medium. Chemical mass flux is dependent on the morphometry of the plant species, on exposure concentration, and on partitioning character of the chemical. The steady-state bioconcentration factor (KSH) is dependent on composition of the plant species and partitioning character of the chemical. The model was parameterized for three species of aquatic plants (Myriophyllum spicatum, Bacopa caroliniana, and Hydrilla verticillata) and two chlorinated benzenes (1,2,3,4-tetrachlorobenzene [TCB] and 1,2-dichlorobenzene [DCB]). Predictions of uptake and bioconcentration are compared to results of static laboratory studies conducted with whole shoots of the three species over exposure periods ranging from 1 h to 21 d. Predicted tissue burdens and Ksh values are generally within one standard deviation of measured values. Shoots approach steady-state tissue burdens between 1 and 3 d after initial exposure. Ksh values for TCB (360-750), the more hydrophobic chemical, are at least an order of magnitude greater than those measured for DCB (11-28).
Humans are a sensitive species to some of the biochemical effects of structural analogs of dioxin
Authors: Lucier George W.
Published: March 2010

In 1979, rice oil contaminated with polychlorinated dibenzofurans (PCDFs) was ingested in a widespread poisoning episode in Taiwan. The PCDFs are structural analogs of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD and the PCDFs are thought to share the same mechanism of action that involves binding to the Ah receptor. In our studies, we compared the effects of TCDD on rat liver to effects in placentas of women exposed to PCDF-contaminated rice oil. TCDD is a hepatocarcinogen in female rats. Measured parameters included concentrations of human placental PCDF congeners or rat liver TCDD and induction of cytochrome P-450 isozymes, epidermal growth factor receptor (EGFR) and glucocorticoid receptor (GCR). Placentas from PCDF-exposed women contained two PCDFs: 2,3,4,7,8-penta CDF (100 ppt) and 1,2,3,4,7,8-hexa CDF (400 ppt). The 2,3,4,7,8-penta CDF binds the Ah receptor 60% as well as TCDD, and the 1,2,4,7,8-hexa CDF binds 9% as well as TCDD. Cytochrome P1-450 was induced approximately 100-fold in exposed placentas. This induction was considered maximal. Placental PCDF concentrations associated with this induction were compared to the amount of hepatic TCDD required to maximally induce the rat liver homolog of P1-450. These comparisons, accounting for differences in Ah receptor binding, suggested that humans are more sensitive than rats to the P1-450 inductive actions of the toxic halogenated aromatics. Several assumptions are made, and their validity is discussed. As with the P1-450, humans are more sensitive to the effects of the halogenated aromatics on EGFR (EGF-stimulated autophosphorylation) and GCR (binding capacity) than are rats. Although the relationship of these biochemical changes to the carcinogenic effects of TCDD and its analogs is not clear, our data suggest that it is prudent to retain a conservative risk assessment for the toxic halogenated aromatics.
The toxic effects of pollutants on the mineralization of acetate in subsoil microcosms
Authors: van Beelen P. , Fleuren-Kemilä A. K. , Huys M. P. A. , van Montforta A. C. P. , van Vlaardingen P. L. A.
Published: March 2010

The mineralization of [14C]acetate or [14C]glucose was studied in aseptic subsoil samples at 10°C. At 1 μg/L and 100 μg/L, the mineralization showed first-order kinetics preceded by a short lag phase. For the sandy subsurface soils, the half-lives of acetate or glucose varied from 0.5 until 21 d, whereas a peat subsoil and a sandy surface soil produced half-lives of 11 and 1.6 h, respectively.

The EC50 is the toxicant concentration that causes 50% reduction of the percentage substrate mineralized at a certain incubation time and increases with time. The time-independent toxicant concentration IC50 gives 50% inhibition of the mineralization rate and is equal to the EC50 at short incubation times. The IC50 of pentachlorophenol varied between 0.1 and 880 mg/kg subsoil. The aerobic mineralization of acetate in surface sand showed an IC50 of 28 mg pentachlorophenol/kg. Hydrochloric acid showed IC50 values ranging from pH 6.2 to pH 2.8. For chlorite and cadmium, the IC50 values were 34 and 59 mg/kg, respectively.

When soils were incubated with 100 mg acetate/L, exponential growth kinetics were observed. Under these conditions the inhibitory effect of pentachlorophenol was relatively small because the resistant part of the acetate-mineralizing microflora could grow and replace the inhibited part. The kinetics show why toxicity tests using high substrate concentrations are less sensitive than tests using more natural low substrate concentrations. The model predicts that slow-growing microorganisms, which are vital to the functioning of the ecosystem, would recover only very slowly from the toxic effects of environmental pollution.
Uptake and elimination kinetics of organophosphorous pesticides in the guppy(poecilia reticulata): Correlations with the octanol/water partition coefficient
Authors: de Bruijn Jack , Hermens Joop
Published: March 2010

Bioconcentration factors, uptake rate constants and elimination rate constants of a series of organophosphorous pesticides were determined in the guppy (Poecilia reticulata). The results of these three toxicokinetic parameters were related to measured octanol/water partition coefficients (Kow). A simple one-compartment model fitted the uptake and elimination characteristics of the chemicals. A biphasic relationship was observed between log k1 (uptake rate constant) and log Kow, whereas elimination rate constants were inversely related to Kow. For some of the test compounds substantially higher elimination rates were found, compared to isolipophilic chlorobenzenes, which resulted in lower bioconcentration factors. This divergent behavior is discussed in view of possible biotransformation reactions for these compounds.
Assessment of methods for estimating aquatic hazards at superfund-type sites: A cautionary tale
Authors: Burmaster David E. , Menzie Charles A. , Freshman Jonathan S. , Burris Janet A. , Maxwell Nancy Irwin , Drew Scott R.
Published: March 2010

Field studies, laboratory experiments and theoretical calculations were used to estimate the ecological risk caused by the release of toxic organic compounds from the Baird and McGuire Superfund hazardous waste site to the Cochato River, a small river in eastern Massachusetts. The results from the field studies, which included (a) direct measurements of chemical concentrations in sediments and fish tissues; (b) direct measurements of chemical concentrations in dialysis bags filled with hexane and placed in the river; and (c) taxonomic surveys at stations upstream of, adjacent to and downstream of the site, were compared to the results from laboratory tests and computer models, which included (d) toxicity bioassays, (e) toxicity quotients based on the U.S. Environmental Protection Agency's interim sediment quality criteria, and (f) estimates of bioaccumulation using equilibrium and fugacity models. The resulting patchwork of confirmatory and contradictory findings highlights the limitations of available theoretical and laboratory methods and cautions against reliance on any single method of quantifying stress to aquatic ecosystems.
Fate of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (rdx) in soil and bioaccumulation in bush bean hydroponic plants
Authors: Harvey Scott D. , Fellows Robert J. , Cataldo Dominic A. , Bean Roger M.
Published: March 2010

Soils amended with [14C]hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were sampled over 60 d and subjected to exhaustive Soxhlet extraction followed by HPLC analysis. RDX was the only radiolabeled compound observed in soil extracts. Emission of volatile organics and 14CO2 from soil accounted for only 0.31% of the amended radiolabel. Mass balance for RDX-amended soil was better than 84% throughout the two-month study. The analytical method developed for plants involved acid hydrolysis, solvent extraction, fractionation on Florisil® adsorbent and separation by HPLC. The described methodology allowed for RDX recovery of 86 ± 3% from fortified bush bean leaf tissue. Further experiments were conducted with bush bean plants maintained on RDX-containing hydroponic solutions. Hydroponic plants did not emit detectable amounts of 14CO2 or radiolabeled volatile organics. Analysis of the plant tissue indicated bioaccumulation of RDX in the aerial tissues of hydroponic plants exposed for either 1 or 7 d. Metabolism of RDX to polar metabolites was observed in plants exposed for 7 d.
Application of toxicity identification evaluation procedures to the ambient waters of the colusa basin drain, California
Authors: Norberg-King Teresa J. , Durhan Elizabeth J. , Ankley Gerald T. , Robert Eric
Published: March 2010

Pesticides are applied to the rice fields in the Sacramento Valley to prevent the growth of plants, algae and insects that reduce rice yields. Following the pesticide application, field water is released into agricultural drains that in turn discharge into the Sacramento River and delta. Rice irrigation is the largest single use of irrigation water in the Sacramento Valley, and because the irrigation water (or rice return) flows are the primary source of drain effluent during the spring and summer (up to 33% of the total flow), these discharges can significantly affect drain water quality and resident aquatic organisms. Acute and chronic toxicity to freshwater organisms (Ceriodaphnia dubia) was observed in the drain water during the period that coincides with the initial draining of the fields in 1986, 1987 and 1988. In 1988, a toxicity identification evaluation (TIE) was conducted using Ceriodaphnia dubia in an effort to identify the cause of toxicity. Both methyl parathion and carbofuran were identified as possible toxicants. Mixture tests and chronic toxicity tests indicated that the concentrations of methyl parathion and carbofuran in the water sample account for the toxicity observed in Ceriodaphnia dubia.
Effects of dietary boron and arsenic on the behavior of mallard ducklings
Authors: Whitworth Molly R. , Pendleton Grey W. , Hoffman David J. , Camardese Michael B.
Published: March 2010

High concentrations of boron and arsenic have been associated with irrigation drain water and aquatic plants consumed by waterfowl. Both compounds affect the central nervous system and cause generalized physiological distress in mammals and waterfowl. We examined sublethal effects of boron and arsenic on the behavior of developing mallard ducklings (Anas platyrhynchos). Day-old ducklings received an untreated diet (control) or a diet containing 100, 400, or 1,600 ppm boron, added as boric acid, or 30, 100, or 300 ppm arsenic, added as sodium arsenate. Activity schedules and behavior durations were analyzed for effects at the various treatment levels. Both boron and arsenic at the highest levels had significant effects on the activity schedules of developing ducklings, including increased time at rest and under the provided heat lamp. We also observed decreases in the amount of time treated ducklings spent in alert behaviors and in the water in comparison to control ducklings. High levels of boron (1,600 ppm) increased feeding time overall but did not increase the amount of food consumed. Arsenic had no effect on feeding behavior. There were no differences found in the durations of behaviors as a result of treatment. These findings, in combination with reported effects on the growth and physiology of ducklings under identical treatments, suggest that reported concentrations of these compounds in aquatic plants in the Central Valley of California could adversely affect normal duckling development and survival.
Relative induction of aryl hydrocarbon hydroxylase by 2,3,7,8-TCDD and two coplanar PCBs in rainbow trout (oncorhynchus mykiss)
Authors: Janz David M. , Metcalfe Chris D.
Published: March 2010

Relative aryl hydrocarbon hydroxylase (AHH) induction potencies of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the two coplanar PCB congeners 3,3′,4,4′-tetrachlorobiphenyl (IUPAC congener 77) and 3,3′,4,4′,5-pentachlorobiphenyl (IUPAC congener 126) were determined in rainbow trout (Oncorhynchus mykiss). Trout were injected intraperitoneally with chemicals dissolved in corn oil. The ED50 for AHH induction in TCDD-injected fish was 0.005 μmol/kg. The ED50s for PCB congeners 126 and 77 were 1.0 μmol/kg and 2.2 μmol/kg, respectively. AHH toxic equivalent factors (AHH-TEFs), or TCDD equivalents, were determined as the ratio of the TCDD ED50 to the ED50 for each PCB congener. AHH-TEFs for congeners 126 and 77 were 0.005 and 0.002, respectively. Toxic equivalent quantities for AHH induction (AHH-TEQs) were calculated by multiplying the TCDD equivalent for each chemical by its concentration in fish at environmental levels. AHH-TEQs, based on whole-body TCDD and PCB concentrations in Lake Ontario rainbow trout, were two- to threefold greater for the coplanar PCBs than for TCDD. Although these data do not necessarily indicate that coplanar PCBs are highly toxic to fish, the results indicate that these compounds have the potential to contribute to the environmental effects of compounds structurally related to TCDD.
Use of fractionation procedures and extensive chemical analysis for toxicity identification of a chemical plant effluent
Authors: Jop Krzysztof M. , Kendall Timothy Z. , Askew Ann M. , Foster Robert B.
Published: March 2010

As a part of a National Pollutant Discharge Elimination System (NPDES) biomonitoring program a series of toxicity tests was conducted with process water from a chemical plant using Ceriodaphnia dubia and Pimephales promelas. There were marked differences among the two tested species. The acute (LC50) values from 96-h static toxicity tests with Pimephales promelas were always lower (higher toxicity) than the values obtained from the invertebrate tests. The concentration of ammonia in the effluent, particularly its un-ionized form (250 mg NH4-N/L, which represents 0.7 mg NH3-N/L), was above the threshold concentration for most freshwater species and therefore was the primary suspect of the toxicity present in the effluent.

Prior to initiation of the toxicity identification evaluation (TIE) program, chemical analyses that included measurements of inorganic and organic parameters were conducted with the effluent. During the TIE fractionation, a portion of the sample was purged with nitrogen to remove volatile organics, and a second portion of the sample was pressure-filtered through a 0.45-μm filter. Because toxicity equal to the whole sample was found in these fractions, a portion of the inorganic fraction was subfractionated into zeolite, clinoptilolite, activated carbon, pH-adjustment, aeration, and cation fractions. The results of these tests confirmed that ammonia played a role in the sample's toxicity. However, when ammonia was removed from the effluent sample, toxicity was still present. Next organic chemicals were fractionated as suspected sources of toxicity. At first, organics were removed from the effluent by passing the filtered sample over an XAD-resin column. Because a portion of the reconstituted organic fraction was toxic, the organic fraction was subfractionated further by extracting with dichloromethane at pH > 11, pH < 2, and pH 7.1. The dichloromethane extracts were toxic, whereas the aqueous portions were not toxic. The neutral extract, which was more toxic than the basic and acidic extract, was further fractionated by using HPLC. Seventeen HPLC fractions were isolated and tested for toxicity to determine which constituent(s) were responsible for the observed whole effluent toxicity.
Polycyclic aromatic hydrocarbons and mutagens in ambient air particles sampled in Thessaloniki, Greece
Authors: Viras L. G. , Siskos P. A. , Samara C. , Kouimtzis TH. , Athanasiou K. , Vavatzanidis A.
Published: March 2010

Seventy samples of airborne particulates were sampled from two sites in Thessaloniki, Greece, during the period of one year, starting in July 1987. Thessaloniki is located in the northeastern part of Greece and is the second most highly populated city of the country. The 24-h samples were taken by using high-volume samplers located in two monitoring sites — 1 and 2. Site 1 was located at the center of the city (main pollution sources were traffic and central heating), whereas site 2 was in the industrial zone of the city (main sources were industrial activities and traffic). The collected particulates were examined for their mutagenicity with the Ames test. The analysis of particulates to determine their content in polycyclic aromatic hydrocarbons (PAHs) was done by the gas chromatographic method. The column used to separate the various PAHs was a wide-bore capillary column. Ten PAHs were identified and quantified in the atmosphere of Thessaloniki. No essential differences were found between the mean values of PAH concentrations measured at the two sites, whereas the mutagenicity values at site 1 (central area) were higher than those measured at site 2 (industrial site). The PAH concentrations were moderate if compared with those found in other polluted cities in the world, whereas the mutagenic activity of particulates was low. Higher values of PAH concentrations and mutagenicity were found during winter. During Sundays the PAH concentrations were lower than those measured on weekdays. No significant linear correlation was found between PAH concentrations and mutagenicity for both sites of measurements. The main sources of PAHs were estimated to be the stationary sources in winter and the traffic in summer for both measuring sites. Higher values of both PAH concentrations and mutagenicity were found during days with light winds.
Nitroblue tetrazolium dye reduction by earthworm (lumbricus terrestris) coelomocytes: An enzyme assay for nonspecific immunotoxicity of xenobiotics
Authors: Chen Shing Chong , Fitzpatrick Lloyd C. , Goven Arthur J. , Venables Barney J. , Cooper Edwin L.
Published: March 2010

Earthworm (Lumbricus terrestris) coelomic leukocytes, or coelomocytes, were shown to have sufficient ability to reduce nitroblue tetrazolium dye (NBT) for potential use as a surrogate biomarker to assess nonspecific immunotoxicity of environmental xenobiotics. NBT reduction is used clinically to evaluate potential of human leukocytes to oxidatively kill phagocytosed microorganisms. Coelomocyte NBT reduction, which exhibited time–response patterns similar to those of human and murine neutrophils and murine macrophages, was sensitive to Cu and/or Pb contaminants in refuse-derived fuel fly ash (RDFF). NBT reduction by coelomocytes from earthworms exposed for 5 d to RDFF:commercial soil mixtures decreased significantly with increasing sublethal RDFF concentrations of 10, 30, 50, and 70%. Compared to soil-exposed controls, dye reduction was significantly suppressed in all but the 10% RDFF group: 40, 59, and 64% of controls, respectively. Differences were significant among experimentals, except between 50 and 70% RDFF. Tissue levels of Cu and Pb accorded with RDFF exposure concentrations in which suppression of NBT reduction occurred. NBT reduction was not significantly suppressed in coelomocytes from earthworms exposed to 70% fly ash that had been acid-washed to remove metals.
Allozymic variability in toxicity-testing strains of ceriodaphnia dubia and in natural populations of Ceriodaphnia
Authors: Snyder Thomas P. , Switzer Kristen M. , Keen Robert E.
Published: March 2010

Ceriodaphnia dubia Richard used in 7-d chronic toxicity testing from six environmental testing centers were assayed for allozymic variability at 11 enzymatic loci. Ten of the eleven scored loci were monomorphic and homozygous in all six stocks. One stock was homozygous for an alternative electromorph, as compared to the other five, at the glucose-6-phosphate dehydrogenase (G6PDH) locus. Laboratory stocks comprise two morphologically distinguishable forms of Ceriodaphnia dubia that may be environmentally determined. Ceriodaphnia lacustris and Ceriodaphnia reticulata from natural populations showed within- or between-population allozymic variability at 8 of the 11 loci, suggesting Ceriodaphnia possesses genetic variability equivalent to that of other cladocerans. The three species of Ceriodaphnia are closely related, having only one diagnostic electromorph that separates Ceriodaphnia dubia from the other two species. Possible causes of the monomorphism of the laboratory stocks are discussed.
Response of polyamines to heavy metal stress in oat seedlings
Authors: Wettlaufer S. H. , Osmeloski J. , Weinstein L. H.
Published: March 2010

Polyamine titers in oat seedlings (Avena sativa L.) were evaluated as possible biomarkers for heavy metal stress. The titers were measured in response to the addition of 20 metal salts. Six of those metal salts were chosen for further study: chromium, cobalt, copper, mercury, nickel, and silver. Changes in polyamine titer in response to the addition of the six metal salts were specific for each metal, but were generally smaller when compared to changes in polyamine titer associated with other forms of plant stress reported in the literature. Changes in putrescine titer, over time, were also specific for each metal, but did not correlate well with the changes in the enzymatic activity of its biosynthetic enzyme, arginine decarboxylase. We conclude that polyamine metabolism and arginine decarboxylase activity are not effective as general biomarkers for evaluating heavy metal stress in oat seedlings.
Mutagenicities of hydroxy-substituted carbazoles and dibenzothiophenes using the CHO/HGPRT assay
Authors: Rasmussen Kathy , Booth Gary M. , Lee Milton L. , Castle Raymond N.
Published: March 2010

Eight hydroxylated carbazoles and dibenzothiophenes were tested for mutagenic activity using the CHO/HGPRT mutation assay for thioguanine resistance. All showed increased activity over carbazole and dibenzothiophene. Some of the hydroxycarbazoles showed slightly higher activity than the corresponding hydroxy-dibenzothiophenes (71.4 ± 5.2 mutants/106 survivors for 1-hydroxycarbazoles compared to 21.8 ± 6.1 mutants/106 survivors for 4-hydroxydibenzothiophene at 5 μg/ml, and 32.8 ± 3.3 mutants/106 survivors at 5 μg/ml for 4-hydroxycarbazole as compared to 16.4 ± 0.9 mutants/106 survivors for 1-hydroxydibenzothiophene at 5 μg/ml). The most mutagenic compound was 1-hydroxycarbazole, which also exhibited cytotoxicity. The relative order of mutagenic activity of the hydroxycarbazoles was 1 ≥ 4 > 2 = 3 > carbazole, and the relative activity of the hydroxydibenzothiophenes was 2 ≥ 3 > 1 = 4 > dibenzothiophene. Overall, the mutagenic activity of the hydroxycarbazoles and hydroxydibenzothiophenes was dependent on the structural position of the hydroxy group.
Sensitivity of bacterioplankton in the Rhine river to various toxicants measured by thymidine incorporation and activity of exoenzymes
Authors: Tubbing Diny M.J. , Admiraal Wim
Published: March 2010

Natural populations of bacteria in water samples from the lower Rhine River were tested for their sensitivity to selected toxicants. Bacterial growth, measured as [3H-methyl] thymidine incorporation, was affected by additions of 5 μg Cu L−1; these concentrations were similar to the copper concentrations found in the river. Concentrates of the organic fraction from river water, obtained via XAD-columns, affected thymidine incorporation in samples of river water when added in concentrations corresponding to ambient levels. The exoenzymatic activities of phosphatase and protease decreased systematically at concentrations higher than 5 μg Cu L−1. Potassium dichromate (K2Cr2O7) at a concentration of approximately 3 mg L−1 and a detergent tetrapropylbenzene sulfonate (TPBS) at a concentration of 5 mg L−1 had detectable effects on microbial activity. Atrazine affected the growth rate but not the enzymatic activity of bacterial populations when this herbicide was added in concentrations of 50 to 200 μg L−1. Thymidine incorporation was more sensitive to all test compounds than the enzymatic activities. It is concluded that the present pollution levels, although decreased, are still likely to affect microbial processes in the river.
Variability in the performance of the seven-day fathead minnow (pimephales promelas) larval survival and growth test: An intra- and interlaboratory study
Authors: Degraeve G. M. , Cooney J. D. , Mcintyre D. O. , Pollock T. L. , Reichenbach N. G. , Dean J. H. , Marcus M. D.
Published: March 2010

The U.S. Environmental Protection Agency (EPA) has developed a “Seven-Day Fathead Minnow Larval Survival and Growth Test” for measuring the toxicity of effluents. This study evaluated the ease and performance and the intra- and interlaboratory variability of this 7-d test using two reference toxicants (sodium pentachlorophenate and potassium dichromate), two refinery effluents, and one low-volume internal waste stream from an electric power plant. Ten different laboratories representing academia, private industry, contractors, the state EPA, and the U.S. EPA participated in this study. The reference toxicants were tested twice during two separate test periods, and each effluent and waste stream was tested once. Using EPA's criteria for a successful test, 90% of the 140 planned tests were completed as valid tests. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted concurrently (spatial variability), expressed as the coefficient of variation (C.V.), ranged between 5.9 and 15.6% and between 9.1 and 26.1%, respectively. The intralaboratory variability of the survival (LC50) and growth (IC50) results for tests conducted at two different times (temporal variability), expressed as C.V., ranged between 14.5 and 25.3% and between 17.6 and 22.7%, respectively. The interlaboratory variability of the survival (LC50) and growth (IC50) results, expressed as C.V., ranged between 24.1 and 43.7% and between 22.4 and 88.0%, respectively. Overall, the variability of the 7-d fathead minnow test was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.