bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative metabolism of o-toluidine by the abalone (Haliotis rufescens) and flatfish (Platichthys stellatus)
Authors: Knezovich John P. , Crosby Donald G.
Published: March 2010

Abalone and flatfish excreted 2-nitrosotoluene and N-acetyl-o-toluidine, respectively, as the only biotransformation products of o-toluidine. The elimination of o-toluidine over a 4-h period was high for both species (greater than 80%), but the total extent of metabolism was low (less than 2%). A Sprague-Dawley rat was used to compare the metabolic pathways typically found in mammals with those found in the marine organisms. Metabolism of o-toluidine by the rat was extensive (greater than 95%), and ring-hydroxylated conjugates were rapidly eliminated.

The metabolic capabilities of terrestrial vertebrates are more extensive than those found in aquatic organisms and may reflect the greater need for water conservation in terrestrial species. Aquatic organisms such as molluscs may not be at a disadvantage, however, because many such compounds are likely to be eliminated by passive diffusion.
Toxicity of pure pentachlorophenol and chlorinated phenoxyphenol impurities to fathead minnows
Authors: Hamilton Steven J. , Cleveland Laverne , Smith Lawrence M. , Lebo Jon A. , Mayer Foster L.
Published: March 2010

The toxicities of pure (greater than 99%) pentachlorophenol (PCP) and of a mixture of the major impurities in commercial PCP, composed mostly of octa- and nonachlorophenoxyphenols (POPs), were evaluated in 90-d partial life-cycle toxicity tests with fathead minnows (Pimephales promelas Rafinesque). The exposure concentrations were 8 to 130 μg/L for the pure PCP and 6 to 93 ng/L for the mixture of POPs. A spontaneous conversion of a 2-hydroxy isomer of nonachlorophenoxyphenol in the POPs mixture to octachlorodibenzodioxin was observed in the stock solution and exposure water during the POPs study. Pure PCP did not affect survival, growth or bone development at any concentration tested. The mixture of POPs did not affect survival but did reduce growth in fish exposed to 93 ng/L for 30 d and stimulated growth in fish exposed to 6 to 47 ng/L for 60 d or to 23 to 47 ng/L for 90 d. Bone development was significantly altered by exposure to POPs concentrations of 12 ng/L or higher; collagen concentration was elevated, and both hydroxyproline concentration (a key cross-linking amino acid in collagen) and bone density were reduced. Degeneration of the fins was noted at 30 d of exposure to 93 ng/L POPs, but fin development appeared nearly normal at 90 d. The sublethal effects of POPs at low concentrations, when compared with those of pure PCP, indicate that POPs may be a major contributor in the toxicity of commercial PCP to fish.
Uptake, translocation and metabolism of anthracene in bush bean (Phaseolus Vulgaris L.)
Authors: Edwards Nelson T.
Published: March 2010

The roots of bush bean (Phaseolus vulgaris L.) plants growing in nutrient solution were exposed to [side ring-U-14C]anthracene (0.01 mg L−1 solution) during flowering and seed production. At harvest, 60% of the total 14C dose was in the roots, 3% in the stems, 3% in the leaves, 0.1% in the pods, 17% in the nutrient solution and 16% unaccounted for. More than 90% of the anthracene (75 mg/plant) was metabolized over the 30-d exposure period. The results suggest that most of the metabolism occurred in the plant tissues. At harvest, 8.7% of the anthracene dose was found (unmetabolized) in the roots, 1.5% in the nutrient solution, 0.53% in the stems and 0.03% in the leaves. Quantities of the parent compound were too small to detect in the pods and seeds. The remainder of the [14C]anthracene taken up by the plants was metabolized to polar metabolites (29%) and nonpolar metabolites (18%) or structurally incorporated into compounds that were not extracted (44%).
DDT contamination of a North Alabama aquatic ecosystem
Authors: Reich Andrew R. , Perkins Jimmy L. , Cutter Gary
Published: March 2010

Between 1947 and 1970, Olin Chemical Company discharged an estimated 4.32 × 105 to 8.0 × 106 kg of DDT residues (DDT, DDD and DDE) into Huntsville Spring Branch and Indian Creek in Alabama. Residents of Triana, Alabama, located approximately 10 mi downstream from the outfall, have been found to have high tissue levels of DDT residues. A comprehensive investigation of the contaminated area conducted by Tennessee Valley Authority and others in 1979 indicated extensive contamination of the ecosystem.

This study investigated the environmental dynamics of DDT residues in the Huntsville Spring Branch-Indian Creek aquatic ecosystem by assessing residue levels in sediment, water and benthic macroinvertebrates collected in September 1983 during a 3-d period. Analytical results revealed continued heavy DDT residue contamination of all three media. Water and sediment data exhibited an exponential decrease in residues with increasing distance below the outfall. Sediments showed concentrations of residues of up to 2% by weight. Benthic macroinvertebrates also displayed high levels of DDT residues. Water bioconcentration factors ranged from 1,737 to 99,700 for total residues.

DDT residue levels in Indian Creek-Huntsville Spring Branch are still extremely high 14 years after the input of DDT was stopped. There has been no significant change in contamination levels during the 4-year interim between this study and the previous TVA study.
Seasonal effects on microbial transformation rates of an herbicide in a freshwater stream: Application of laboratory data to a field site
Authors: Lewis David L. , Freeman Leonard F. , Watwood Mary Elizabeth
Published: March 2010

Seasonal effects on microbial transformation rates of an herbicide, 2,4-dichlorophen-oxyacetic acid butoxyethyl ester (2,4-DBE), in a freshwater stream were investigated using low concentrations (less than 100 μg L−1) of the herbicide mixed with an inert dye, rhodamine WT, to correct for dilution. Although water temperatures decreased from 22 ± 0.5 to 8.0 ± 0.5°C and water velocities decreased from 0.09 ± 0.01 to 0.03 ± 0.003 m s−1, microbial transformation rates, as indicated by pseudo-first-order transformation rate coefficients, increased as much as threefold in the cold months over those in the spring and summer. The increased winter transformation rates were associated with leaf-litter accumulation, which provided additional colonized surface area in the stream. Therefore, the increased colonized surface area more than compensated for the effects of temperature and water velocity (under conditions of mass-transport limitation) that otherwise would have reduced microbial transformation rates in the winter months.
A quantitative method for evaluating avian food avoidance behavior
Authors: Kononen Douglas W. , Hochstein John R. , Ringer Robert K.
Published: March 2010

Food avoidance experiments could contribute to assessments of animals' behavioral responses to environmental toxicants. Food avoidance tests with mallards (Anas platyrhynchos L.) and northern bobwhite (Colinus virginianus L.) as the test species were patterned after avian 5-d dietary LC50 tests. Animals in each treatment group were given free access to untreated feed and feed treated with various concentrations of methiocarb (3,5-dimethyl-4-(methylthio)-phenyl methylcarbamate), a widely used bird repellent. Prior to food avoidance testing, 5-d dietary LC50 tests were conducted to provide baseline data for comparison. A measure of avoidance response was estimated from a log (dose)-probit (response) analysis. The percentage of total (treated plus untreated) feed consumption as treated feed consumption was the response variable. The detectable dietary concentration at which mallards and bobwhite began to avoid a specific contaminant was determined by calculating a median food avoidance concentration 50 (FAC50). In the absence of detectable avoidance behavior, test animals' total feed consumption can be expected to consist of equal amounts of treated and untreated feed. An effective avoidance index (EAI), LC50/FAC50, was used as a measure of a toxicant's “margin of safety.” Calculated results for methiocarb were as follows: for mallard, LC50 = 7,469 ppm, FAC50 = 145 ppm, EAI = 51.5; for bobwhite, LC50 = 827 ppm, FAC50 = 95 ppm, EAI = 8.7.
Aluminate toxicity as a factor controlling plant growth in bauxite residue
Authors: Fuller R. D. , Richardson C. J.
Published: March 2010

Millions of metric tons of alkaline bauxite residue (red mud), produced annually in aluminum refineries at numerous locations around the world, are stored in large, diked impoundments. Bauxite residue is characterized by high pH (9 to 12), high concentrations of soluble sodium, carbonate and aluminate and low concentrations of the major plant nutrients. Establishment of a functioning ecosystem on these derelict lands requires an understanding of the ecological factors limiting plant growth. A series of organic amendments to bauxite residue was tested in order to increase the growth of Distichlis spicata var. stricta (desert saltgrass), an alkaline-tolerant rhizomatous grass. Sewage sludge-amended residue increased shoot growth more than 10 times than did unamended or nutrient-amended residue. Yield was negatively correlated with shoot Al and Fe concentrations' and positively correlated with shoot N, K, P, Ca and Mg content. A hydroponic culture experiment was used to test the effects of high pH (9.5 and 10.5) and aluminate addition (1.0 mM) on the growth of desert saltgrass. Although elevated pH levels reduced Mn uptake, there was very little reduction in growth. The addition of aluminate, however, reduced shoot weight by 67 and 77% at pH 9.5 and 10.5, respectively. Growth reductions were associated with significant declines in shoot P, N, Mg, Ca and K concentrations. At pH 9.5, reductions in shoot P concentrations were associated with large increases in root Al and P levels. At pH 10.5, however, precipitation of an Al-Mg hydroxycarbonate mineral was associated with a decline in shoot Mg levels. Aluminum toxicity appears to be a major factor controlling plant growth in bauxite residue. Possible Fe toxicity needs to be investigated further. Sewage sludge may reduce the toxicity of bauxite residue by lowering pH, precipitating Al and increasing cation availability via complexation.
Xenobiotic metabolism of p-nitrophenol derivatives by the rice field crayfish (procambarus clarkii)
Authors: Foster Gregory D. , Crosby Donald G.
Published: March 2010

The extent and routes of metabolism affect the bioconcentration and toxicity of xenobiotics in crayfish. To investigate the in vivo xenobiotic metabolism of three p-nitrophenol derivatives, rice field crayfish were exposed to 0.1 to 0.01 mg L−1  14C-substrate solutions for 15 h. At apparent steady-state uptake, the crayfish were transferred to a recycling flow-through metabolism chamber for 24 h where the depurated products were collected and concentrated on a column of Amberlite XAD-4 resin. The tissue absorption and distribution of 14C-compounds at the apparent steady-state and post depuration periods were measured by complete tissue combustion and recovery of evolved 14CO2. The structure and concentration of metabolites in resin and soft tissue extracts were determined by cochromatography with authentic standards in HPLC and TLC systems. The crayfish rapidly absorbed the radiolabeled chemicals from solution and depurated metabolites of oxidation and conjugation reactions. The most prominent metabolites were the β-D-glucosides of the free phenols, with lesser amounts of the corresponding sulfate esters. Observed oxidations included O-demethylation, aromatic sidechain oxidation and phosphorothioate deesterification. Body burdens of the original p-nitrophenol derivatives were markedly reduced by the presence of these metabolic transformations.
Determination of uptake rate constants for six organochlorines in midge larvae
Authors: Lohner Timothy W. , Collins William J.
Published: March 2010

Various methods are used to measure the residue-forming potential of organic chemicals in aquatic organisms. The majority of these studies have been conducted with fish and rely on the determination of steady-state partitioning, a method that is expensive, both in terms of time and analytical cost. The midge (Chironomus riparius) is readily available, easily cultured and provides an alternative system with which to study chemical uptake. To evaluate this system, the uptake rate constants of six organochlorines were determined under nonequilibrium conditions, using the midge.

Uptake rate constants were calculated from uptake data using a first-order kinetic expression. Significant correlations were found between the uptake constants of the six chlorinated hydrocarbons and their water solubility and octanol/water partition coefficient values. Multiplying the uptake constants by their molecular weight provided values that were highly correlated with log octanol/water partition coefficients (r2 = 0.93) and log aqueous solubility (r2 = 0.97) when analyzed by linear regression. Using the midge, uptake constants can be determined in a short time and may be used to make reliable predictions about the relative penetrating power of many chemicals in aquatic invertebrates.
Estimating sample requirements for field evaluations of pesticide leaching
Authors: Smith Charles N. , Carsel Robert F. , Parrish Rudolph S.
Published: March 2010

A method is presented for estimating the number of samples needed to evaluate pesticide leaching threats to ground water at a desired level of precision. Sample size projections are based on desired precision (exhibited as relative tolerable error), level of confidence (90 or 95%) and estimates of variability (expressed as the coefficient of variation) for selected pesticide and soil characteristics.

Summary tables of descriptive statistics are provided as guides for projecting variability of various soil characteristics, pesticide properties (sorption, degradation), pesticide concentration profiles and inorganic solutes. These data were compiled through a comprehensive search of review articles and of reports of laboratory and field studies. The parameters selected are measurements generally required for conducting field pesticide leaching studies. They are also useful for evaluating ground water contamination by calibrating and conducting sensitivity testing with solute transport models. Coefficients of variation for selected soil characteristics were as follows: bulk density, 2 to 17%; organic matter, 42 to 125%; porosity, 4 to 18%; particle size distribution, 3 to 55%; hydrogen ion activity, 2 to 15%; 0.3 bar water content, 18 to 82%; 15 bar water content, 18 to 87%; saturated hydraulic conductivity, 48 to 320%; and infiltration rate, 40 to 97%.

Coefficients of variation for selected pesticide characteristics were as follows: transformation rates, 7 to 202%; sorption coefficients, 34 to 56%; and pesticide concentration profiles, 40 to 450%. Variability of pesticide concentrations increased over time after the initial pesticide application. The coefficients of variation for inorganic solutes ranged from 19 to 127%.

On the basis of these data, sample size estimates (for constant desired precision and confidence level) for characterizing selected soil characteristics generally are smaller than those required for estimating pesticide concentrations. Fewer samples are projected for estimating pesticide concentrations shortly after application, with progressive increases required in later sampling.
Products of hexachlorocyclopentadiene (C-56) in aqueous solution
Authors: Chou Sheng-Fu J. , Griffin Robert A. , Chou Mei-In M. , Larson Richard A.
Published: March 2010

The photodegradation and degradation products of hexachlorocyclopentadiene (C-56) in aqueous solutions were studied in the laboratory. In each case, the half-life of C-56 was less than 4 min when exposed to sunlight. At least eight degradation products were positively or tentatively identified: 2,3,4,4,5-Pentachloro-2-cyclopentenone, hexachloro-2-cyclopentenone and hexachloro-3-cyclopentenone were the primary photodegradation products, and pentachloro-cis-2,4-pentadienoic acid, Z- and E-pentachlorobutadiene and tetrachlorobutyne were the secondary degradation products. Dissociation of the primary photolysis products may proceed through corresponding pentadienoic acids to form smaller molecular weight compounds such as pentachlorobutadiene isomers and tetrachlorobutyne. In addition, dimerization of 2,3,4,4,5-pentachloro-2-cyclopentenone to form higher molecular weight compounds such as hexachloroindenone may present a minor route of degradation. The results also indicate that C-56 is highly photoreactive and suggest a possible pathway for the compound's transformation in the environment when exposed to sunlight.
Laboratory studies on mechanisms for the degradation of aldicarb, aldicarb sulfoxide and aldicarb sulfone
Authors: Lightfoot E. N. , Thorne Peter S. , Jones Russell L. , Hansen James L. , Romine R. R.
Published: March 2010

Experiments were performed in order to better define the degradation mechanisms and kinetics for aldicarb and its two metabolites, aldicarb sulfoxide and aldicarb sulfone. The mechanisms studied were oxidation in surface soil and saturated zone soil samples, degradation in saturated zone soil samples and distilled water hydrolysis. The studies showed that soil is an important mechanistic factor, probably because surface catalysis occurs. Temperature and pH are important factors in determining degradation rates. The experiments seem to indicate that microbial oxidation is an important degradation mechanism in the surface soil, but the breakdown of aldicarb residues to noncarbamates is largely the result of chemical hydrolysis. The reduction of aldicarb sulfoxide to aldicarb was observed in the presence of limestone but only after an incubation period of two to six months. No reduction of aldicarb sulfone to aldicarb sulfoxide was observed in these experiments. The complexity of degradation is such that laboratory studies can augment but not replace well-designed experiments conducted under actual field conditions.
Structural features associated with degradable and persistent chemicals
Authors: Niemi Gerald J. , Veith Gilman D. , Regal Ronald R. , Vaishnav Dinesh D.
Published: March 2010

A multivariate statistical method and a heuristic method were employed to examine the structural features associated with the persistence or degradation of 287 chemicals tested with the standard biochemical oxygen demand (BOD) procedure. The data base consisted of 196 “degradable” chemicals with a half-life of less than 15 d (e.g., Theoretical BODs (ThOD) > 16%) and 91 “persistent” chemicals with a half-life of more than 15 d. The multivariate statistical analysis consisted of (1) calculating 54 molecular connectivity indices, five physicochemical properties and eight principal components from the molecular connectivity indices, (2) clustering the chemicals on the basis of the principal components and one of the physicochemical properties, Kow and (3) discriminating between persistent and degradable chemicals using the molecular connectivity indices and the physicochemical properties as discriminating variables within each cluster. The heuristic approach used the results of the multivariate analyses and the literature on biodegradation to identify a series of structural features associated with degradable and persistent chemicals.

The best iteration of the multivariate technique correctly predicted 85% of the degradable chemicals and 94% of the persistent chemicals. In contrast, the heuristic approach correctly predicted 91% of the degradable chemicals and 96% of the persistent chemicals. Twelve structural features or chemical classes were associated with degradable chemicals and 16 structural features were associated with persistent chemicals. The analysis is presented as a potential technique for rapidly assessing the relative degradability of discrete organic chemicals. The structural features identified are offered as tentative hypotheses to be examined with a larger and more diverse data set.
Uptake and release of fluoride in arctic char
Authors: Christensen B.
Published: March 2010

Fluoride levels were measured in Arctic char (Salvelinus alpinus) living near Narsaq. The Narsaq River is unpolluted, but has naturally high levels of fluoride—varying from about 2 mg/L in summer to 10 to 20 mg/L in winter. The river has a relatively large population of Arctic char which appears unaffected by the high fluoride level. Stationary char accumulate fluoride in muscles (16.6 mg/kg) and bones (1,150 mg/kg), while char caught in the estuary have concentrations similar to char from reference areas (6.5 mg/kg in muscle, 439 mg/kg in bone). It is concluded that Arctic char accumulate fluoride when living in the high-fluoride freshwater environment, but that concentrations return to normal in anadromous char during the 1 to 2 summer months annually spent at sea.
Dynamics of organochlorine compounds in herring gulls (Larus argentatus): II. A two-compartment model and data for ten compounds
Authors: Clark Thomas P. , Norstrom Ross J. , Fox Glen A. , Won Henry T.
Published: March 2010

A two-compartment open model using plasma and seasonally variable lipid compartments was developed and validated for several organochlorines in herring gulls (Larus argentatus). Plasma clearance rate constants (k′pc, L·kg−1·d−1), plasma: whole-body lipid partition coefficients (Kpf) and compartment sizes for lipid and plasma were obtained for juvenile gulls injected i.p. with a mixture of p,p′-DDD, p,p′-DDE, hexachlorobenzene, oxychlordane, γ-hexachlorocyclohexane, trans-chlordane, octachlorostyrene, dieldrin, mirex and photomirex. Concentrations in plasma were determined at 11 time points during the 239-d study, and whole-body contaminant burdens and lipid weights were determined at 3 time points. Mean Kpf for p,p′-DDD and p,p′-DDE (0.0038 ± 0.0002) was different from that of the other organochlorines (0.0058 ± 0.0005, n = 7). The latter values were close to the expected fraction lipid in plasma, indicating a simple thermodynamic partitioning between lipid pools in adipose tissue and plasma. Plasma clearance rate constants ranged from approximately 0.04 L·kg−1·d−1 for slowly clearing organochlorines such as p,p′-DDE and mirex to 500 L·kg−1·d−1 for rapidly clearing γ-hexachlorocyclohexane and trans-chlordane. Simulations using these parameters and lipid weight regimes for individual experimental birds tracked observed plasma concentrations and final body burdens closely. Simulated whole-body half-lives of organochlorines in wild adult gulls were similar to those published for other species.
Endpoints for responses of fish to chronic toxic exposures
Authors: Suter Glenn W. , Rosen Aaron E. , Linder Ernst , Parkhurst David F.
Published: March 2010

The concept of chronic toxicity has caused confusion in fish toxicology because it has developed four connotations: long duration, inclusion of all life stages, low severity, and high sensitivity. To compare alternate chronic tests and expressions of test results, we extracted concentration-response data from published life-cycle, partial-life-cycle, and early life-stage tests and derived concentration-response relationships by nonlinear regression. The effects examined were reductions in parental survival, fecundity, hatching success, larval survival, weight of early juveniles, and weight of early juveniles per egg. On the average, the most sensitive effect was reduction in fecundity, not effects on early life stages. We also found that maximum acceptable toxicant concentrations (MATCs) corresponded to fairly high levels of effect; mean reductions at the MATC were parental survival, 20%; fecundity, 42%; hatching, 12%; larval survival, 19%; weight, 20%; and weight/egg, 35%. These results indicate that, on average, MATCs are concentrations that cause substantial effects and that MATCs estimated from early life-stage tests are not good substitutes for life-cycle tests. We suggest that the acute-chronic dichotomy be abandoned in favor of tests and benchmarks based on concentration-duration-response dynamics.
Modelling phytotoxic activity of herbicidal triazines by molecular properties: A pls approach
Authors: Cesareo D. , Tosato M. L. , Clementi S.
Published: March 2010

The phytotoxicity of herbicidal triazines has been analyzed as a function of a number of physicochemical molecular properties by the PLS (partial least squares in latent variables) method for the purpose of generating QSAR-type models. The analysis was carried out on an initial set of 20 chemicals; the PLS models were able to explain percentages of the variance of the activity up to 91%. In each model the variance of the phytotoxicity was mainly explained in terms of four out of the eight considered descriptors: practically all information needed for modelling the biological activity was contained into descriptors related to the mobility of triazines and, in particular, to their partitioning among phases of different chemical composition and polarity. No relevance was found for such descriptors as molecular weight, redox properties, and ionization constants.
The uptake, distribution and metabolism of four organic chemicals by soybean plants and barley roots
Authors: Nolt Cynthia , McDowell Mike , Wickliff Carlos , Pfleeger Tom , Shimabuku Ray , McFarlane Craig
Published: March 2010

The uptake of bromacil, dichlorobenzonitrile (DCBN), nitrobenzene (NB) and dinitrobenzene (DNB) was studied in isolated barley roots and mature soybean plants. The uptake rate constants for soybean plants were in the order of DCBN = bromacil < NB < DNB. The same pattern was evident for the root tissue test, except for DNB. Metabolism of the 14C-labeled chemicals indicated that DCBN was metabolized in the leaves but not in the roots. DNB was metabolized in the roots, and bromacil remained primarily as parent compound. A method for obtaining uptake rate constants is described.
Wet process copying machines: A source of volatile organic compound emissions in buildings
Authors: Tsuchiya Yoshio , Clermont M. J. , Walkinshaw D. S.
Published: March 2010

The total volatile organic compounds and profiles of volatile organic compounds of indoor air in several office buildings with libraries were studied, mainly using sorption tubes and GC-MS. Exhaust vapors from wet-process-type copying machines proved to be a major source of the volatile organic components of the indoor air.
Use of selenastrum capricornutum to assess the toxicity potential of surface and ground water contamination caused by chromium waste
Authors: Greene Joseph C. , Miller William E. , Debacon Mary , Long Michael A. , Bartels Cathy L.
Published: March 2010

United Chrome Products, Inc. (Corvallis, OR), discharged liquid chrome-plating wastes into an on-site dry well from 1957 to 1977. Samples were collected from ground and surface waters during February and December 1984 and evaluated for toxicity potential using 96-h Selenastrum capricornutum bioassays. Bioassays of the February samples were used to calculate predicted EC50 values for different chromium concentrations, which were then compared with the chromium concentrations measured in the December samples and with the results of S. capricornutum bioassays on these samples. An excellent correlation was obtained between the predicted EC50 values and the actual bioassay response values for ground water and drainage ditch samples. However, no correlation was obtained with the off-site surface water samples. These results could not be explained by changes in chromium valence, and they demonstrate that, even in simple systems, toxicity cannot readily be predicted based solely on chemical analysis.
Determination of dose-time-response relationships from long-term acute toxicity test data
Authors: Hong Wuk-Hee , Meier Peter G. , Deininger Rolf A.
Published: March 2010

Long-term exposures over 96 h provide valuable information on the behavior of toxic chemicals that cannot be obtained from short-term tests. Time-dependent LC50 and dose-time-response plots are important in evaluating the toxicity of chemical compounds to test organisms. However, their use is limited because of cumbersome calculations. To circumvent this, a BASIC program was developed that is based on the multivariate linear model theory. The main program, MULTILC, runs on an IBM PC and generates an equation that describes dose-time-response relationships. From this equation, time-dependent LC50 values and their 95% confidence intervals are calculated. In addition, the subprogram, 3DGRAPH, draws a series of plots on the computer screen, including a three-dimensional dose-time-response surface.
Nitrilotriacetic acid (NTA) environmental monitoring program in Indiana: 1979 to 1983
Authors: Wendt R. H. , Payne A. G. , Hopping W. D.
Published: March 2010

The environmental concentrations of nitrilotriacetic acid (NTA) resulting from its use in laundry detergents were monitored during a four-year study conducted in central Indiana. The purpose of the study was to measure NTA concentrations in municipal wastewater, in surface waters that receive wastewater effluent and in finished drinking water from surface waters downstream from the outfalls of wastewater treatment plants. The 25 sampling sites were interdependent locations in and around Indianapolis, Indiana, an area that received laundry detergents containing Na3NTA at a level equivalent to 3.6% NTA in all detergents (w/w) during the last two years of the program. NTA removal during wastewater treatment averaged 91% (w/w) at activated sludge treatment plants and 65% at trickling filter plants. NTA concentrations averaged 0.008 μg/ml in river waters and 0.004 μg/ml in drinking waters when NTA-containing detergents were in use. NTA concentrations in wastewaters, river waters and drinking waters were similar to or lower than concentrations predicted from usage levels and agreed, within a factor of 3, with the predicted values.

Concentrations of six metals (Cu, Ni, Cd, Pb, Cr and Zn) were also measured in samples collected throughout the program. Concentrations of the metals in influent wastewater, their removal by wastewater treatment and their concentrations in river and finished drinking waters were comparable with values typical in the United States. Use of NTA in laundry detergents did not affect metals removal by wastewater treatment or metals concentrations in river and drinking waters.
Aerobic biodegradation of natural and xenobiotic organic compounds by subsurface microbial communities
Authors: Swindoll C. Michael , Aelion C. Marjorie , Dobbins Durell C. , Jiang Ou , Long Sharon C. , Pfaender Frederic K.
Published: March 2010

Studies were conducted to characterize the diversity of degradative abilities of microbial communities from pristine aquifer solids samples. Biodegradation was measured in aquifer solids slurries as both the conversion of radiolabeled substrate to 14CO2 and the incorporation of label into cell biomass. Under aerobic conditions, the microbial community metabolized the following naturally occurring compounds: acetic acid, amino acids, cellulose, cinnamic acid, glucosamine and glucose. The xenobiotic compounds aniline hydrochloride, chlorobenzene, p-chloro-phenol, m-cresol, ethylene dibromide, naphthalene, phenol, toluene and trichlorobenzene were also biodegraded. Several kinetic parameters were calculated from the uptake and mineralization data. First-order rate constants (K1) ranged from 10−2 to 10−4 h−1 for the natural compounds and from 10−3 to 10−6 h−1 for the xenobiotic compounds. Turnover times ranged from 47 to more than 1,900 h for natural compounds and from 806 to 60,000 h for xenobiotic compounds. For some compounds, respiratory enzymes became saturated, whereas incorporation into biomass was first-order. The results show that uptake into cell biomass represents a large fraction of total metabolism for many of the xenobiotic compounds. 14C-most-probable-number (MPN) of substrate degraders was calculated. MPNs for naturally occurring compounds ranged from 102 to 106 per gram of soil. There were generally fewer than 10 xenobiotic degraders per gram of soil. The biodegradative activity of the subsurface community appears to differ in both rate and product distribution from the activities of aquatic or surface-soil communities.
Air pollution and wildlife toxicology: An overlooked problem
Authors: Newman James R. , Schreiber R. K.
Published: March 2010

Since the 1880s, there have been repeated reports worldwide of toxic effects to wildlife from air pollution. Incidents in North America were recorded as early as the 1920s and as recently as last year. The effects have ranged from death and injury to increased incidence of infectious diseases, and they are the result of exposure to both gaseous and particulate emissions. Compared with other threats to wildlife, for instance, pesticides, the toxicological relationship between air pollution and effects in wildlife is not well understood. Our limited understanding is based primarily on reports of symptoms observed in the field and on information extrapolated from studies in livestock and laboratory animals. Few controlled wildlife studies, such as those that have evaluated pesticide effects, have been conducted. Current air quality standards cannot be assumed to protect wildlife from the effects of air pollution.

This article reviews the current state of knowledge of air pollution and wildlife toxicology and the continuing threat air pollution presents to wildlife. The available information on reported effects of gaseous and particulate pollutants (i.e., sulfur dioxide, hydrogen sulfide, oxidants, arsenic, cadmium, fluoride, lead and selenium) on terrestrial wildlife, along with similar toxicological data for domestic animals, is summarized. Information on the toxic effects, tolerance levels, pathways of contamination, and risks to wildlife from air pollution is given, and gaps in knowledge are pointed out. Areas where research is needed are identified.
Changes in mallard hen and brood behaviors in response to methyl parathion- induced illness of ducklings
Authors: Fairbrother Anne , Bennett Richard S. , Meyers S. Mark
Published: March 2010

Half the young in each of four broods of 5-d-old mallards (Anas platyrhynchos) were gavaged orally with 4 mg/kg methyl parathion and released with their mother and untreated siblings in pond enclosures. Four control broods received corn oil only. Activity categories (swimming, preening, feeding, loafing) of hens and broods were noted every 15 min and continuous observations were made of length of time to recovery or death (dosed ducklings) and of time spent in a behavior. Observations were made for 4 h following release, for an additional 2 to 4 h that afternoon, and for 2 h the following morning. Control broods were on water during 22 of 37 observations, while treated broods were on land more frequently than on water (43 of 51 observations). There was a significant difference (χ2 = 76.4, p < 0.001) between behaviors of treated and control broods; treated broods mostly preened and loafed on land while control broods primarily fed and swam in open water. Hens remained with their broods and kept all ducklings together even when dosed young were too sick to move (for 90 to 155 min posttreatment). Forty percent of dosed ducklings died the first day, whereas no control ducklings died. The results of this study indicate that methyl parathion can affect the brood-rearing phase of reproduction by direct mortality and through behavioral changes.
Characterization of agricultural nonpoint pollution: Nutrient loss and erosion in a West Tennessee watershed
Authors: Klaine S. J. , Hinman M. L. , Winkelmann D. A. , Martin J. R. , Sauser K. R. , Moore L. W.
Published: March 2010

Research was conducted on an 18-ha, bermed, single-field watershed in west Tennessee to characterize soil and nutrient losses during storm events over a 12-month period. Total soil loss was approximately 104 metric tons, which is high for the nation but typical for west Tennessee. Minimums of 2% of applied phosphorus and 6% of applied nitrogen were lost from the field through storm water runoff. First-flush analysis indicated that total suspended solids, orthophosphate, ammonia, and total Kjeldahl nitrogen migrated from the field faster than if proportional to the flow. In general, orthophosphate came off the field early in the runoff event, whereas other forms of phosphorus came off late in the event.
The mixed function oxidase system of bluegill sunfish, Lepomis macrochirus: Correlation of activities in experimental and wild fish
Authors: Jimenez Braulio D. , Burtis Lisa S. , Ezell George H. , Egan B. Z. , Lee Norman E. , Beauchamp J. J. , McCarthy J. F.
Published: March 2010

Environmental conditions can affect the metabolic transformation and accumulation of pollutants in aquatic organisms. Changes in temperature and feeding regimes had marked effects on the hepatic O-deethylation of 7-ethoxyresorufin (EROD) activity in bluegill sunfish. Animals that were denied food and acclimated for 2 weeks to 4, 13 or 26°C water exhibited low and relatively uniform EROD activity at all temperatures. In contrast, fed fish acclimated at 26°C exhibited a sevenfold higher level of activity compared with those acclimated to 4°C. Starved fish acclimated to 26°C were capable of EROD induction following intraperitoneal (i.p.) injection with benzo[a]pyrene (BaP). Doses of 10 and 20 mg BaP kg−1 body weight increased EROD activity to 100 and 300 nmol min−1 mg−1 respectively, compared with 10 nmol min−1 mg−1 in fish injected with corn oil. Wild fish obtained from various stations along a polluted stream exhibited EROD activity levels comparable with those in laboratory fish injected with 20 mg BaP kg−1 fish. When starved fish were injected i.p. with a Purina Trout Chow extract, EROD activity was induced to levels comparable with those in laboratory-fed (Trout Chow) fish; this suggests the presence of an inducer in the Trout Chow. Exposure of fed fish to pH 5, 7 and 9 for a 2-week period at 26°C had no effect on the mixed function oxidase (MFO) activity in fish liver microsomes. The results of this study indicate that environmental variables can affect the levels of MFO activity. A better understanding of these effects is needed before these indicators can be used routinely as environmental monitors.
Comparison of procedures for recovering chloroguaiacols and chlorocatechols from contaminated sediments
Authors: Remberger Mikael , Hynning Per-ÅKe , Neilson Alasdair H.
Published: March 2010

Procedures for the extraction of chloroguaiacols and chlorocatechols from contaminated sediment samples were examined. Using one sample, a comparison was made of the following procedures: solvent extraction with water-miscible solvents, steam distillation, Soxhlet extraction with t-butyl methyl ether, and several more aggressive methods employing BF3/methanol, HBr/water and KOH/methanol. The recoveries of the chlorinated compounds were highly variable. Recovery of the chloroguaiacols by the nonaggressive procedures was generally low, but it was significantly greater using methanolic alkali. The efficacy of the latter procedure was confirmed by the data obtained with three other sediment samples. Qualitatively similar differences in recoverability were also observed when a high molecular weight alkali-stage chlorolignin was examined. Therefore it was not possible to determine whether the monomeric chlorinated compounds were bound to natural organic compounds in the sediment or to the chlorolignin, which is produced during the bleaching process. In an experiment using one sediment sample incubated under anaerobic conditions for nine months, no change occurred in the amount of extractable chloroguaiacols and there was an approximate 40% reduction in the corresponding chlorocatechols. It is therefore postulated that the binding mechanisms of the chloroguaiacols and chlorocatechols in the sediment phase are significantly different, and that an indeterminate fraction is not accessible to microbial transformation. There are, it is noted, inherent limitations to interpreting the results of experiments on binding and desorption in which xenobiotics are exposed to the sediment phase for only a short time.
Principles of toxicity testing with marine unicellular algae
Authors: Walsh Gerald E.
Published: March 2010

Toxicity testing with unicellular algae requires application of the principles of phycology and microbiology to culturing, handling and exposing the organisms. This brief review describes major aspects of algal toxicity testing, including growth curves, factors that influence population growth in culture (light, temperature, medium composition, pH and salinity), choice of test species, measurement of population density, enumeration of living and dead cells, numerical expression of toxic effects and bioaccumulation.
Mutagenic potential of drinking waters from surface supplies in Northern Italy
Authors: Galassi S. , Guzzella L. , Sora S.
Published: March 2010

Raw and drinking waters collected from three surface supplies in northern Italy (River Po at Turin and Ferrara, Lake Como at Como) were extracted using XAD resins to concentrate organic micropollutants. The extracts were tested for their ability to cause mutations in the Salmonella reversion system and mitotic gene-conversion or recombination in Saccharomyces. Ferrara and Como extracts were found to have mutagenic activity in both the Salmonella and Saccharomyces tests. Turin water was never found to be mutagenic. Toxic and nontoxic extracts were then analyzed by GLC and HPLC to identify the mutagenic compounds. Although the mutagenic activity could not be explained by analytical measurements, some anthropogenic compounds, probably related to the observed effects, were identified in genotoxic samples.
Toxicity of synthetic pyrethroids to freshwater invertebrates
Authors: Anderson Richard L.
Published: March 2010

This report reviews the laboratory toxicity data on freshwater target and nontarget invertebrates exposed to pyrethroids and evaluates the state of the data. Early in their development, pyrethroids were shown to be highly effective insecticides against mosquitoes, blackflies and chironomids. Acute LC50 values for these target animals were often less than 1 μg/L. Acute exposures of nontarget invertebrates showed that some species were as sensitive as the target insects. Longer exposures, up to 28 d, showed that lethal effect concentrations were lowered with increased exposure duration. Unfortunately, the long—exposure tests were limited to a few species and a few pyrethroids, so no general commentary on no effect concentrations is possible. Some species were affected at concentrations near the analytical detection limit for pyrethroids. The data reviewed show that temperature, life cycle stage and exposure duration will be critical factors in developing the no effect concentrations that are important in risk assessments for nontarget invertebrates exposed to these insecticides.
Toxicology of synthetic pyrethroids in aquatic organisms: An overview
Authors: Coats J. R. , Symonik D. M. , Bradbury S. P. , Dyer S. D. , Timson L. K. , Atchison G. J.
Published: March 2010

The aquatic toxicology of the photostable synthetic pyrethroid insecticides as it affects two important groups of susceptible organisms — fish and aquatic insects — is discussed. The sensitivity of these aquatic species to the pyrethroids is dependent on several factors, including toxicokinetics, target site (nervous system), sensitivity and possible secondary mechanisms of action, as well as chemical and physical properties of the aquatic medium that influence toxicity and bioavailability. Uptake rates and routes of fenvalerate greatly affected the toxicity of fenvalerate to mosquito larvae. LD50 values were determined for cuticular and dietary exposure routes by utilizing radiolabeled fenvalerate at the respective LC50 concentrations in the two media (water and food). Fenvalerate was sixfold more toxic to mosquito larvae by the cuticular route. Technical fenvalerate was more toxic to larvae than was the emulsifiable concentrate formulation. Addition of different concentrations of humic acid to the water reduced the toxicity to the larvae. Review and analysis of relevant literature are integrated into a discussion of the principles and details of aquatic toxicology of the pyrethroids.
Effect of sediment organic carbon on survival of hyalella azteca exposed to DDT and endrin
Authors: Nebeker Alan V. , Schuytema Gerald S. , Griffis William L. , Barbitta Janet A. , Carey Lori A.
Published: March 2010

Sediment toxicity tests were conducted with the freshwater amphipod Hyalella azteca using sediments ranging in total organic carbon (TOC) concentration from 3 to 11 % and spiked with either DDT or endrin. While the toxicity in the DDT-spiked sediment decreased with increasing TOC content, the TOC content of the endrin-spiked sediment had little apparent effect on toxicity. The 10-d sediment dry-weight LC50 for DDT was 11.0 μg/g at 3.0% TOC and 49.7 μg/g at 10.5% TOC. The sediment dry weight LC50s for endrin at 3.0 and 11.2% TOC were 4.4 and 6.0 μg/L, respectively. These results are important in evaluating the carbon normalization theory, which assumes that the availability of nonpolar organic compounds is reduced in the presence of higher concentrations of TOC. The differences in adsorption and toxicity between DDT and endrin are presumably related to the smaller carbon (Koc) and octanol/water (Kow) partition coefficients of endrin.
Experimental evaluation of the mysid Holmesimysis costata as a test organism for effluent toxicity testing
Authors: Martin Michael , Hunt John W. , Anderson Brian S. , Turpen Sheila L. , Palmer Francis H.
Published: March 2010

Laboratory experiments were conducted to evaluate the mysid crustacean Holmesimysis costata as a test organism for routine complex effluent toxicity testing. Three-day-old juvenile mysids, hatched in the laboratory from field-collected gravid females, were used in repetitive 48-h and 96-h mortality tests. With zinc sulfate as a reference toxicant, mean 96-h LC50 and no observed effect concentration (NOEC) values for Holmesimysis were 97 and 56 μg/L, respectively, lower than previously reported values for other crustacea. Different laboratories conducting the 96-h mortality test with Holmesimysis produced significantly different results in one trial, but results from different laboratories were not significantly different in the second trial. Coefficients of variation between laboratories for LC50s and NOECs were 24 and 33%, respectively, in the first trial, and 25 and 1%, respectively, in the second trial. Juvenile mysids aged 3, 5, 7 and 9 d old responded similarly to zinc exposure, though control mortality differed among these groups. Gravid female mysids were less sensitive, and 1-d-old mysids had high control mortality; neither group was suitable for toxicity testing. The NOEC for zinc effects on growth was 18 μg/L in a 7-d experiment. LC50 and NOEC values for copper were 27 and <11 μg/L (the lowest concentration tested), respectively. Effluents from four municipal sewage treatment plants (primary through secondary) produced LC50s ranging from 4.5 to 64.0% effluent, and NOECs ranging from 1.0 to 32% effluent, depending on the level of effluent treatment.
Rapid detection of sublethal toxicity using fish ventilatory behavior
Authors: Diamond Jerome M. , Parson Marolyn J. , Gruber David
Published: March 2010

Significant changes in bluegill sunfish ventilation were observed at chronically toxic levels of various substances in under 1 h of exposure and usually within 15 min of exposure. A different ventilation response was observed between the heavy metal compounds and the chlorinated hydrocarbon substances. The response to metals zinc and cadmium was characterized by: (a) decrease in signal amplitude and (b) increase in Type I (large volume) coughs or gill purges. The response to chlorinated hydrocarbons was characterized by: (a) increase in erratic movement, (b) increase in gill purges and (c) increase in ventilatory frequency. Our results suggest that fish ventilatory monitoring can provide a powerful tool for rapidly assessing sublethal as well as acute toxicity on a real-time basis. Furthermore, the type of response generated may be indicative of the type of toxicant in the environment.