bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of artificial burrows inHexageniatoxicity tests: Recommendations for protocol development
Authors: Henry M.G. , Chester D.N. , Mauck W.L.
Published: March 2010

Hexagenia are an important component of fish and waterfowl diets, provide an ecological link in the conversion of detritus to usable nutrients and are useful test organisms for monitoring trends in aquatic contaminants. Consequently, Hexagenia bilineata were used in toxicity tests to determine their sensitivity to leachate from spent shale oil and to evaluate the influence of including artificial glass burrows in exposure chambers. Gill beat frequency and mortality were significantly higher (p = 0.01) in nymphs that were not afforded an opportunity to burrow than in those exposed to the toxicant but that had access to artificial burrows. Molting frequency was depressed in Hexagenia lacking burrows, and it was further decreased as the amount of toxicant increased. Thus, thigmotactic stress accentuated by the presence of shale oil leachate was relieved by including artificial burrows in the exposure chambers. The resulting toxicity data are more ecologically meaningful because the burrowing life history characteristic of the Hexagenia was addressed and incorporated into the test protocol.
Improved sea urchin DNA-based embryo growth toxicity test
Authors: Jackim Eugene , Nacci Diane
Published: March 2010

This article presents an improved DNA-based embryo toxicity test in which growth is measured as the increase in DNA during a 5-h postfertilization period. The test, using direct fluoro-metric determination of DNA rather than thymidine incorporation, is fast, sensitive, easy to conduct and correlates well with other 48- and 96-h acute aquatic tests. The need for radioisotopes has been eliminated and data variability is substantially reduced. It is recommended that this test be incorporated into a battery of rapid tests used to estimate aquatic toxicity.
Toxicokinetics of fenvalerate in rainbow trout (Salmo Gairdneri)
Authors: Bradbury Steven P. , Coats Joel R. , McKim James M.
Published: March 2010

An in vivo rainbow trout (Salmo gairdneri) preparation was used to evaluate the gill uptake and toxicokinetics of [3H]fenvalerate ([R,S]-α-cyano-3-phenoxybenzyl [R,S]-2-[4-chloro-phenyl]-3-methylbutyrate), a synthetic pyrethroid insecticide. Fish were exposed to technical-grade fenvalerate (0.28 or 23 ng/L) or an emulsifiable-concentrate formulation (16 ng/L) for 36 to 48 h. No significant effects of emulsifiers or fenvalerate concentration on uptake were observed. The overall mean gill uptake efficiency was determined to be 28.6 + 4.4%. Following 8- to 48-h depuration periods, carcass and bile contained 80 to 90% and 10 to 20% of the gill-absorbed doses, respectively. Urine, feces and blood each contained less than 2% of the dose. Significant excretion and blood transport of fenvalerate equivalents were completed within 8 to 12 h after termination of exposure. Specific tissues from trout exposed to 0.28 ng/L fenvalerate were analyzed for fenvalerate equivalents. After a 48-h depuration period, bile contained the highest concentration of fenvalerate equivalents (7,000 pg/g), followed by fat (200 pg/g). Remaining tissues contained 15 to 45 pg/g. Analysis of biliary metabolites indicated that the glucuronide of 4′-HO-fenvalerate was the only significant degradation product. Results from the present study suggest that efficient gill uptake does not explain the extreme sensitivity of fish to fenvalerate. Rather, a low rate of biotransformation and excretion may play a significant role in the susceptibility of rainbow trout to the synthetic pyrethroid insecticides.
Methoxychlor distribution, dissipation, and effects in freshwater limnocorrals
Authors: Solomon Keith R. , Yoo Jai Y. , Kaushik Narinder K. , Day Kristin E. , Stephenson Gladys L. , Lean David
Published: March 2010

Methoxychlor was applied to 125-m3 limnocorrals at nominal concentrations of 3 and 300 μg L−1 in 1981 and of 5 and 50 μg L−1 in 1982. The half-life of methoxychlor in water ranged from 6 to 13 d; however, methoxychlor was strongly adsorbed to and slowly released from the polyethylene liners and the sediments on the bottom of the enclosures. Forced mixing of methoxychlor in the water resulted in greater adsorption to the sediments than did surface application. Methoxychlor had little effect on water chemistry parameters, although nitrite and dissolved inorganic carbon concentrations were higher in the treated than in the control corrals in each year of the study.
Partitioning of heavy metals to suspended solids of the flint river, michigan
Authors: McIlroy Lyn M. , Depinto Joseph V. , Young Thomas C. , Martin Scott C.
Published: March 2010

The sorptive affinity of copper and zinc to suspended river sediments was investigated as a function of pH and adsorbent solids concentration. Water samples from the Flint River in Michigan were centrifuged to yield a composite sediment concentrate used as an adsorbent in experiments determining pH adsorption edges and conditional adsorption isotherms. Copper and zinc exhibited sharp pH adsorption edges at pH values of approximately 4 to 5.5 and 6 to 7, respectively. Both metals exhibited fractional adsorption decreases as total metal in the system increased. Adsorbent concentration increases were shown to cause decreases in measured copper partition coefficients. The indirect relationship between adsorbent concentration and partition coefficient was observed whether the adsorbent was concentrated or diluted without altering bulk solution chemistry. A mathematical formulation that incorporated both the adsorbent mass effects and the separation of sorbed metal into reversible and resistant components satisfactorily described the observations.
Photochemistry of halogenated benzene derivatives: Part VII. Photoincorporations of polychlorobenzenes with humic model monomers in aqueous acetonitrile solutions
Authors: Choudhry Ghulam Ghaus , Webster G. R. Barrie , Van Den Broecke Just Anton , Hutzinger Otto
Published: March 2010

Aqueous acetonitrile solution-phase photoincorporations of six polychlorobenzenes (PCBzs) into some humic model monomers such as benzoic acid, benzaldehyde, vanillic acid, vanillin, syringic acid and syringaldehyde were investigated using UV light centered at 300 nm. All the PCBzs studied except hexachlorobenzene yielded photoproducts by the reaction of the poly-chlorophenyl radicals with the individual humic monomers. Chlorophenylation of humic model monomers occurred in the case of benzoic acid and benzaldehyde; substituted polychlorodiphenyl ethers were also formed when monomers containing a phenolic OH group were present. Furthermore, the irradiation of 1,2,4,5-tetrachlorobenzene in solution in the presence of vanillic acid produced monochloro- and dichloromethoxydibenzofuran carboxylic acids in addition to the other photoincorporated products.
Movement of kepone® (chlordecone) across an undisturbed sediment-water interface in laboratory systems
Authors: Pritchard Parmely H. , Monti Carol A. , O'Neill Ellen J. , Ahearn Donald G. , Connolly John P.
Published: March 2010

The distribution of Kepone® (chlordecone) in a sediment bed after various periods of continuous toxicant input to the overlying water column was determined in a laboratory system. Most of the Kepone was found to accumulate in the top 0.6 to 1.5 cm of sediment. A mathematical model was developed to predict Kepone concentrations with depth over time in the sediment. An equilibrium partition coefficient was determined from batch sorption tests and a molecular diffusion coefficient for Kepone was estimated from an empirical relationship between diffusivity and molecular weight. A computed Kepone distribution based on diffusion rates that decreased with depth and with incubation time gave the best fit to the observed data. We attribute the apparently faster rates in the upper sediment to mixing between interstitial and overlying water. Our results illustrate the value of models in conjunction with laboratory studies in defining the interactions of pollutants with sediment beds.
Mayfly-mediated sorption of toxicants into sediments
Authors: Gerould Sarah , Gloss Steven P.
Published: March 2010

Experiments were conducted to determine the influence of the burrowing mayfly, Hexagenia limbata, on the movement of dihexylphthalate (DHP) and hexachlorobenzene (HCB) from the water column into the sediment. Beakers containing sediment and mayflies were introduced into flow-through aquaria and were sampled at intervals up to 5 d. Sediment was taken from surface and subsurface areas with and without mayflies. The two experiments were run at concentrations of [14C]DHP and [14C]HCB of 0.066 and 0.062 ng/L, respectively.

Subsurface sediment without mayflies was uncontaminated. Toxicant concentration, based on area (ng/cm2), was greater at the surface than on the burrow walls for both compounds. Concentration in the bottom of the burrow was greater than that in the middle (5 cm deep) for DHP but similar to that at the middle for HCB. Total mass of DHP in the burrow wall was about equal to the mass on the surface, indicating that mayflies were capable of doubling the amount of DHP sorbed onto a given surface area of sediment. The adsorption of contaminants from water pulsed through mayfly burrows increased the depth of penetration and mass of contaminants in subsurface sediments.
Selenium bioaccumulation in gonads of largemouth bass and bluegill from three power plant cooling reservoirs
Authors: Baumann Paul C. , Gillespie Robert B.
Published: March 2010

Male and female largemouth bass (Micropterus salmoides, Lacepede) and bluegills (Lepomis macrochirus, Rafinesque) were collected from two power plant cooling reservoirs that received ash pond effluent (Hyco and Catfish Reservoirs, North Carolina) and one that did not (Lake Sangchris, Illinois). Bluegills were also collected from a city reservoir (Roxboro City Lake, North Carolina) that received no industrial effluent. Selenium residues were determined separately in the gonads and in the carcasses of all fish collected. Residues in both carcasses and gonads were significantly higher in fish from reservoirs receiving ash pond effluent. Ovarian selenium concentrations were greater than testicular levels, while concentrations in carcass did not differ between the sexes. Selenium concentrations were significantly higher in the ovaries than in the rest of the carcass in both largemouth bass and bluegills. In males, selenium levels declined in gonads relative to those in the carcass as selenium concentrations in the carcass increased, but no such pattern was evident in females. Bioaccumulation resulted in selenium concentrations 1,000 times higher in the ovaries of bluegills than in the water from which the fish were collected.
Toxicity of o-cresol to mink and european ferrets
Authors: Hornshaw T.C. , Aulerich R.J. , Ringer R.K.
Published: March 2010

The toxicity of o-cresol to mink (Mustela vison) and European ferrets (Mustela putorius furo) was evaluated through dietary LC50 and reproduction tests. Twenty-eight-day LC50 tests with each species resulted in no overt signs of toxicity or mortalities, with the highest dietary concentrations being 2,520 ppm for mink and 4,536 ppm for ferrets. Mink were more sensitive to o-cresol than were ferrets, based on feed consumption, body weight data and hematologic parameters. Both species routinely consumed in excess of the estimated oral LD50 in an average day's feed consumption at the highest dietary concentration. Mink in a reproduction test exhibited no significant adverse effects at dietary concentrations as high as 1,600 ppm over 6 months.
Differences in mortality among bobwhite fed methylmercury chloride dissolved in various carriers
Authors: Spann James W. , Heinz Gary H. , Camardese Michael B. , Hill Elwood F. , Moore John F. , Murray Helen C.
Published: March 2010

Twelve-day-old bobwhite chicks were fed a diet containing 0, 5.4 or 20 ppm methylmercury chloride. The methylmercury chloride was added to the diet either in a dry, pulverized form or dissolved in acetone, propylene glycol or corn oil. Mortality was measured for 6 weeks, and samples of liver were saved for mercury analysis. Mortality was significantly lower in birds fed 20 ppm methylmercury chloride when acetone was the solvent. The reduced mortality could not be explained by effects of acetone on dietary level of mercury or on uptake of mercury into the body.
Analysis of cyanide in whole blood of dosed cathartids
Authors: Krynitsky A. J. , Wiemeyer S. N. , Hill E. F. , Carpenter J. W.
Published: March 2010

A gas-liquid chromatographic method was modified to quantify both unmetabolized (“free”) and metabolized (“bound”, i.e., thiocyanates) cyanides. The methods for both are efficient and sensitive to 0.05 ppm. Repeated freezing and thawing of whole blood from treated cathartids caused an initial increase in free cyanide concentrations, followed by a gradual decline to a plateau. Bound cyanide concentrations declined after repeated freezing and thawing.
Application of molecular topology to quantitative structure-biodegradability relationships
Authors: Boethling Robert S.
Published: March 2010

Simple and multiple linear regressions were applied to the development of models for predicting biodegradability of chemicals from molecular connectivity indexes. Indexes were calculated using the program CFUNC, on the DECsystem 10 computer at the National Institutes of Health, Bethesda, Maryland. Biodegradation data from test systems containing natural media or inocula were obtained from the literature for several homologous series of organic compounds; within each series, all compounds had been tested under the same conditions. The following one-variable models were among those obtained: for 2,4-D alkyl esters, log rate constant versus 2Xv, r2 = 0.954 (n = 6); for N-3-chlorophenylcarbamates, log percent degraded versus 4Xp/c, r2 = 0.971 (n = 7); for dialkyl ethers, log percent theoretical oxygen demand (%ThOD) versus 2Xv, r2 = 0.974 (n = 6); for dialkyl phthalate esters, rate constant versus 2X, r2 = 0.938 (n = 12); for aliphatic acids, %ThOD versus 4Xc, r2 = 0.895 (n = 10). Two-variable models substantially improved results for aliphatic alcohols and acids. These results indicate that the apparent effect of alkyl chain branching on biodegradability can be quantitatively described by connectivity indexes, especially 2X, 3Xc, 4Xc and 4Xp/c, 3Xp also appeared frequently, especially in two-variable models, suggesting a possible role for molecular shape as a determinant of biodegradability. The results suggest that molecular topology holds promise for future research in quantitative structure-biodegradability relationships.
Margins of uncertainty in ecotoxicological hazard assessment
Authors: Slooff W. , Van Oers J. A. M. , De Zwart D.
Published: March 2010

Margins of uncertainty in predicting toxicity from one species to another, from acute to chronic exposures and from single species to higher levels of biological organization were determined by regression and correlation analyses. Based on the acute sensitivities of 35 aquatic species to 15 compounds, no species was found to be particularly sensitive to all chemicals and the 95% uncertainty factor (UF) ranged from 3 to 1,985. Analyses of acute and chronic sensitivities for the same species to 164 chemicals resulted in the acute/chronic relationship log NOEC = -1.28 + 0.95 log L(E)C50 (r = 0.89) and the UF of 25.6 (where NOEC is the no observed effect concentration). Comparison of the lowest acute and corresponding ecosystem effect levels for 34 chemicals indicated the relationship log NOEC(ecosystems) = -0.55 + 0.81 log L(E)C50 (r = 0.77) and the UF of 85.7. As to the predictability of ecosystem effect levels from chronic single-species data, the following relationship was found: log NOEC(ecosystems) = 0.63 + 0.85 log NOEC (r = 0.85), with a UF of 33.5. These data indicate that acute testing is not pointless; it offers a statistical base for the use of acute toxicity information in the hazard assessment of chemicals in the aquatic environment.
Bioaccumulation and effects of some technical triaryl phosphate products in fish and Nitocra Spinipes
Authors: Bengtsson B.-E. , Tarkpea M. , Sletten T. , Carlberg G. E. , Kringstad A. , Renberg L.
Published: March 2010

Three commercial triaryl phosphates, Pliabrac 521, Reofos 95 and Reolub hyd 46, were tested for acute toxicity against the brackish-water harpacticoid Nitocra spinipes Boeck (Crustacea) and the zebra fish, Brachydanio rerio Hamilton-Buchanan. The 96-h LC50 values ranged from 0.27 to 1.75 mg/L, with Pliabrac 521 as the most toxic and Reolub hyd 46 as the least toxic. The zebra fish was more than 10 times less sensitive to the tested compounds than was N. spinipes. Low to moderate accumulation of triaryl phosphates was observed. An accumulation factor (AF) of 100 to 2,000 was observed for Pliabrac 521 from water to bleak, Alburnus alburnus L. For the various triaryl phosphates, a dietary accumulation of 0.06 to 0.6 from food to minnow, Phoxinus phoxinus L., was observed. The most hydrophilic compounds were readily cleared from fish when the fish were placed in clean water, whereas the most lipophilic ones were still detectable, albeit in low concentrations, in the fish after a 2-week depuration period. A rotatory-flow behavioral study did not reveal any effects on swimming performance in the bleak, but reproduction was affected as a result of long-term (163 d) exposure of minnows to subacute concentrations of Pliabrac 521.
Evaluation of Sesoil, Przm and Pestan in a laboratory column leaching experiment
Authors: Melancon Susan M. , Pollard James E. , Hern Stephen C.
Published: March 2010

Four 2-m columns filled with sandy soil were loaded with six organic chemicals (dicamba, 2,4-dichlorophenoxyacetic acid, atrazine, diazinon, pentachlorophenol, and lindane) and watered for 30 d in a controlled laboratory experiment. Chemical migration was monitored by analyses of daily effluent samples and soil sample cores, the latter collected on day 30 from 5-cm compartments throughout each column. Observed chemical migration patterns were compared with the predictions of three vadose zone fate-and-transport models: SESOIL, PRZM and PESTAN. Two sets of comparisons with the observed data were conducted using input data either obtained from the literature or derived from laboratory measurements using the actual experimental chemicals and soil. Evaluations of model performance revealed substantial variability depending on the chemical type and model tested. PRZM and PESTAN showed greater improvement in prediction of observed chemical migration patterns with the use of measured input data than did SESOIL. The limitations of these models, if used for screening purposes without a priori measurement of chemical- and site-specific model input data or post hoc calibration with existing field data, should be recognized.
Effects of coal pile leachate on Taylor Brook in western Massachusetts
Authors: Tan Barrie , Coler Robert A.
Published: March 2010

The metals in Taylor Brook, a second-order stream that receives the runoff and leachate from a coal pile, were analyzed and evaluated for toxicity. Al, Fe and Mn levels were highest immediately downstream from the coal pile at site 4, where the pH was 4.9. The water at this site was soft (41 ppm). Ca and Mg were predominantly unbound, yet maximum binding with organic acids occurred. The increase in SO4 concentrations (fourfold) and HCO3:SO4 ratios indicated little or no buffer capacity but the SO4:NO3:Cl ratios showed that the effect was local rather than a consequence of acid precipitation alone. The 96-h LC50 values for guppies in water from sites 4 and 3 were 26 and 100%, respectively. The increase of Al (80-fold) was inversely proportional to pH, but this proportionality was more pronounced at site 4 than at site 3. The 36-h LC50 values obtained on the addition of Al and acidity to water from site 3 at the levels measured in water from site 4 were 24% and greater than 100%, respectively. When compared with the values (17% and 49%) derived for site 4 water, the data indicate that the toxicity was principally exerted by aluminum. Residual oxygen data also suggest that fish mortality was primarily a function of Al. Additions of Al (0.3 ppm) to Taylor Brook control site water resulted in increased toxicity to guppies, while added acidity (pH 4.5) had no marked effect.
Acute and chronic effects of water quality criteria-based metal mixtures on three aquatic species
Authors: Spehar Robert L. , Fiandt James T.
Published: March 2010

Acute and chronic toxicity tests were conducted with three aquatic species to determine the effects of metals combined as mixtures at proposed water quality criteria concentrations and at multiples of the LC50 and maximum acceptable toxicant concentration (MATC) obtained from tests on six metals. These studies were the first part of a larger research effort to derive water quality criteria for combined pollutants by the U.S. Environmental Protection Agency.

Arsenic, cadmium, chromium, copper, mercury and lead combined at criterion maximum concentrations caused nearly 100% mortality in rainbow trout and daphnids (Ceriodaphnia dubia) during acute exposures. Fathead minnows were not adversely affected at this or two times this concentration, although a mixture of four to eight times the maximum value caused 15 to 60% mortality. Metals combined at the criterion average concentrations significantly reduced production of daphnid young and growth of fathead minnows after 7 and 32 d, respectively. Embryo hatchability and survival of rainbow trout were reduced at four times this criterion but not at the criterion average concentration.

Acute tests with metals mixed at multiples of the LC50 indicated that the joint action of the metals was more than additive for fathead minnows and nearly strictly additive for daphnids, based on toxic units calculated from the individual components of the mixture. Chronic tests showed that the joint action was less than additive for fathead minnows but nearly strictly additive for daphnids, indicating that long-term metal interactions may be different in fish than in lower invertebrates. Adverse effects were observed at mixture concentrations of one-half to one-third the MATC for fathead minnows and daphnids, respectively, suggesting that components of mixtures at or below no effect concentrations may contribute significantly to the toxicity of a mixture on a chronic basis. These results point out the need for additional studies to determine the type and degree of interaction of toxicants because single-chemical water quality criteria may not sufficiently protect some species when other toxicants are also present.
Survival of daphnia magna and hyalella azteca in cadmium-spiked water and sediment
Authors: Nebeker Alan V. , Onjukka Samuel T. , Cairns Michael A. , Krawczyk Daniel F.
Published: March 2010

Freshwater sediments and water were spiked with cadmium in the laboratory, and toxicity tests were conducted with the cladoceran Daphnia magna and the amphipod Hyalella azteca to determine if Cd in the sediment would cause increased toxicity. The 48-h LC50 values for Daphnia in tests without sediment were 36, 33, 24 and 40 μg/L total Cd. Calculated free ion (Cd2+) LC50 values for the same tests were 28, 25, 18 and 31 μg/L. LC50 values (48-h) determined for total Cd (uncentrifuged water sample) in the sediment-containing beakers were 252, 69 and 122 μg/L for Daphnia. LC50 values for dissolved Cd (centrifuged 10,000 rpm) in the sediment-containing beakers were 61, 27 and 100 μg/L for Daphnia. Higher total Cd LC50 values indicate that Cd adsorbed to soluble organic material was not biologically available. The 96-h LC50 value in tests without sediment for Hyalella was 8 μg/L total Cd; two 10-d LC50 values were less than 2.8 and 6.0 μg/L. LC50 values (96-h) determined for Hyalella for total and dissolved Cd in tests with sediment were 74 and 6.6 μg/L, respectively; the 10-d LC50 for total Cd in tests with sediment was 80 μg/L. No significant mortality of Daphnia or Hyalella occurred in the flow-through tests in which sediment contained the same levels of Cd as in the static tests. Mortality was similar in beakers with and without Cd-spiked sediment, indicating that Cd in the sediment and adsorbed to organic materials was not available to cause increased mortality.
Sediment quality criteria from the sediment quality triad: An example
Authors: Chapman Peter M.
Published: March 2010

Broad-scale comparative data for sediment chemistry, sediment bioassays and bottom fish histopathology are used to derive quantitative site-specific sediment criteria for three representative chemical contaminants in Puget Sound, Washington. The criteria, in terms of concentrations at or below which biological effects have been shown to be minimal, are (dry weight sediment): lead, 50 μg/g (ppm); combustion polyaromatic hydrocarbons, 3.8 μg/g; total polychlorinated biphenyls, 0.1 μg/g.
Tracking river plumes with volatile halocarbon contaminants: The St. Clair river-lake St. Clair example
Authors: Kaiser Klaus L. E. , Comba Michael E.
Published: March 2010

The concentrations of seven widespread, volatile, halocarbon contaminants–tetrachloroethylene (C2Cl4), carbon tetrachloride (CCl4), 1,1,1-trichloroethane (C2H3Cl3), trichloroethylene (C2HCl3), chloroform (CHCl3), bromodichloromethane (CHBrCl2) and Freon 12 (CCl2F2)–were determined in the lower reaches of the St. Clair River and throughout Lake St. Clair. The results indicate large inputs of carbon tetrachloride and tetrachloroethylene and smaller loadings of chloroform, 1,1,1-trichloroethane and trichloroethylene from the St. Clair River, particularly the South Channel, Bassett Channel and Chenal Ecarte, to Lake St. Clair. In total, daily loadings of more than 100 kg are indicated, resulting in a lake burden of approximately 1,000 kg of these halocarbons.

The plumes of contaminated river water, particularly for carbon tetrachloride and tetrachloroethylene, extend approximately 15 km into the shallow, well-mixed lake. At that range, the halocarbon levels generally drop to near-background concentrations, suggesting significant removal of the waterborne contaminants through volatilization.
Biolog, biodeg, and fate/expos: New files on microbial degradation and toxicity as well as environmental fate/exposure of chemicals
Authors: Howard Philip H. , Hueber Amy E. , Mulesky Barbara C. , Crisman Jenny S. , Meylan William , Crosbie Erin , Gray D. Anthony , Sage Gloria W. , Howard Karen P. , Lamacchia Anthony , Boethling Robert , Troast Richard
Published: March 2010

The environmental fate/exposure data base (EFEDB) has been under development with U.S. Environmental Protection Agency support since 1979. It was initiated because of the difficulty of identifying environmental release, fate and exposure information using traditional literature searches. Two new components (BIOLOG and BIODEG), which contain microbial toxicity and biodegradation information, and an update of the overall EFEDB file are described. In addition, a chemical fate/exposure file (FATE/EXPOS) is discussed; it contains production and use data as well as physical-chemical properties, chemical fate data and monitoring information. EFEDB has been greatly expanded since its initial development, and considerable conversions are planned to make most of the files available through the Chemical Information System (CIS). A major goal of EFEDB was to provide a source of data for constructing structure-activity correlations and BIODEG is one of the first steps in providing evaluated data for such correlations. FATE/EXPOS provides sorting capabilities for setting priorities in testing or regulation based on easily obtainable information about exposure potential.
Combined and separate effects of cadmium, lead and zinc on ALA-D activity, growth and hemoglobin content indaphnia magna
Authors: Berglind Rune
Published: March 2010

The single and combined effects of cadmium, lead and zinc on δ-aminolevulinic acid dehydratase (ALA-D) activity, growth and hemoglobin content were studied in Daphnia magna. The ALA-D activity was enhanced by Cd and inhibited by Pb. The binary combinations, Pb:Cd and Pb:Zn, were powerful inhibitors of ALA-D. However, in the combination of the highest concentrations of lead and zinc the activity of ALA-D was enhanced. The stimulation by cadmium was abolished in the presence of zinc. All tertiary combinations of Pb, Cd and Zn inhibited ALA-D activity. Lead alone did not decrease the hemoglobin content in D. magna even at 260 μg/L Pb, but in combination with zinc the decrease was abolished. Tertiary combinations of Cd, Pb and Zn were not more powerful in affecting the hemoglobin content than were the binary combinations. Growth was not affected by Cd, Pb or Zn in any of the combinations used.
Comparison of short-and long-term sexual reproduction tests with the marine red alga champia parvula
Authors: Thursby Glen B. , Steele Richard L.
Published: March 2010

A 2-d exposure test using the marine red alga Champia parvula was developed to assess the toxic effects of pollutants entering the marine and estuarine environments. The initial exposure was followed by a 5- to 7-d recovery period to allow the development of any cystocarps (evidence of sexual reproduction, the endpoint measured). The 2-d exposure test was validated by comparison with a previously developed 2-weed tests in which “no sexual reproduction” was used as the reproductive endpoint. The 2-d procedure is intended for use in testing both single compounds and complex effluents. Complex effluents, however, cannot be accurately tested with the 2-week test; therefore, only single compounds were used to compare the two procedures. Nine single compounds were tested. Concentrations that resulted in a 95% or greater decrease from the control response with the 2-d exposure were considered the best estimate of the no sexual reproduction response from the 2-week test. All of the single compounds tested, except cadmium, yielded essentially the same results with both tests.
Physical and chemical factors that influence the anaerobic degradation of methyl parathion in sediment systems
Authors: Wolfe N. L. , Kitchens B. E. , Macalady D. L. , Grundl T. J.
Published: March 2010

The kinetics of disappearance of methyl parathion (0,0-dimethyl-0-p-nitrophenyl phosphorothioate) were studied in anaerobic sediment samples in the laboratory as a function of methyl parathion concentration, pH and Eh. The disappearance of methyl parathion is described by first-order kinetics and amino methyl parathion (0,0-dimethyl-0-p-aminophenyl phosphorothioate) was identified as a reduction product. In the strongly reducing sediments, the half-lives were on the order of a few minutes. In water isolated from the sediment, no reaction could be detected over the period of a week. Also, there is no apparent correlation between the first-order disappearance rate constants and the pH of the sediment samples. In heat-sterilized sediments, the disappearance rate constants are retarded about two orders of magnitude relative to nonsterile sediments. In chemically treated sediments, first-order disappearance rate constants are comparable to those in the nonsterile system.
Comparison of computer model predictions with unsaturated zone field data for aldicarb and aldoxycarb
Authors: Jones Russell L. , Black Gary W. , Estes Tammara L.
Published: March 2010

The ability of the Pesticide Root Zone Model (PRZM) to simulate the movement of aldicarb or aldoxycarb residues was evaluated using the soil properties and amounts of rainfall and irrigation measured in 34 unsaturated zone field study plots. Maximum leaching depth values obtained from the PRZM simulations agreed relatively well with those observed in the field experiments. Where irrigation water was applied in spatially nonuniform patterns to a field (as in furrow or flood irrigation), simulations show that the placement of the pesticide in relation to irrigation water must also be considered. The comparisons presented in this paper show that PRZM (if supplied with the proper degradation rates and appropriate soil, weather and agricultural parameters) can be used to assess movement of pesticides in agricultural environments. When used in conjunction with multiple year rainfall records, this model can be used to develop probability distributions of pesticide movement in the unsaturated zone. PRZM can also be linked to a ground water solute transport model to provide predictions of pesticide concentrations and transport in ground water. These techniques are useful in performing risk assessments and in developing potential management practices when needed.
Toxicological studies of benomyl and carbendazim in rainbow trout, channel catfish and bluegills
Authors: Palawski Donald U. , Knowles Charles O.
Published: March 2010

Benomyl and carbendazim exhibited high acute toxicity to channel catfish, Ictalurus punctatus (Rafinesque), but were much less toxic to rainbow trout, Salmo gairdneri (Richardson), and bluegills, Lepomis macrochirus (Rafinesque). Changes in water temperature, pH, and water hardness altered the acute toxicity to fish of both compounds; however, the alterations were less marked in channel catfish than in rainbow trout. Carbendazim injected intraperitoneally was not readily metabolized and was the major radioactive product excreted by the three fish species. The rapid depuration of radiocarbon into the containment water and the storage of residues in the gall bladder of each species indicated that both branchial and biliary excretion were major pathways for the elimination of carbendazim by fish. In the carbendazim residue dynamic studies, rainbow trout had the highest uptake rate constant and bioconcentration factor of the three species. Much less carbendazim was accumulated by channel catfish than by the other two species, but this residue level (0.44 μg/g) appeared to be lethal after 48 h of exposure. The elimination rate constant and biological half-life of carbendazim were similar for rainbow trout and bluegills; however, the elimination rate constant was larger and the biological half-life shorter in channel catfish than in the other two species. It was concluded that benomyl and carbendazim were selectively toxic to channel catfish compared with rainbow trout and bluegill, but because of the instability of benomyl and the fast elimination of carbendazim, the possibility of these compounds excessively bioconcentrating in fish was remote.
The relationship between aquatic toxicity QSARs and bioconcentration for some organic chemicals
Authors: Mccarty L. S.
Published: March 2010

Aquatic toxicity testing is conducted largely by means of a single experimental protocol-the concentration-response toxicity test. This procedure has a number of well-known limitations resulting from the fact that the relationship between the waterborne toxicant concentration and the actual body toxicant concentration which is producing the observed biological response is unknown. Hence quantifying the influence of chemical potency, physical, chemical and biological factors and elapsed time on the outcome of toxicity tests is difficult. Interpretation, and even more significantly, predictability may be severely restricted. Using, and further quantifying, the links between octanol-water partition coefficients, bioconcentration and acute and chronic toxicity quantitative structure-activity relationships (QSARs) for narcotic organic chemicals has allowed the following conclusions to be made: (1)Establishing internal toxicant concentrations related to acute and chronic effects, as estimated in this paper, will allow the toxicological significance of body burdens of certain organic chemicals, both singly and in certain mixtures, to be determined.(2)Chemical potency, as determined in the exposed organism, appears to be essentially constant for each of the biological responses and organic chemical groups examined.(3)The acute and chronic QSARs discussed herein are all parallel, each having a slope of unity.(4)It appears, as a first approximation, that a one-compartment, first-order kinetics model could provide a quantitative means of studying aquatic toxicity test results, both retrospectively and prospectively.(5)Bioconcentration and toxicity kinetics appear to be similar, but the internal toxicant concentration endpoint is different, fixed for toxicity and variable for bioconcentration.
Biodegradation data evaluation for structure/biodegradability relations
Authors: Howard Philip H. , Hueber Amy E. , Boethling Robert S.
Published: March 2010

Previous attempts at structure/biodegradability relations (SBRs) and available biodegradation data are reviewed and it is concluded that (1) not enough rate data on large numbers of chemicals are available to develop quantitative SBRs and (2) attempted qualitative SBRs have suffered from either poor documentation of the biodegradation evaluation or they have used limited biodegradation test data. Because of the poor reproducibility of biodegradation tests, a weight-of-evidence evaluation procedure is proposed. A system for collecting and evaluating biodegradation data from screening tests, biological treatment simulations, grab sample tests and field studies is described and study-specific and summary biodegradability codes in combination with reliability codes are developed that can be used for structure/biodegradability relations.
Reduction in bioavailability of organic contaminants to the amphipod pontoporeia hoyi by dissolved organic matter of sediment interstitial waters
Authors: Landrum Peter F. , Nihart Sheila R. , Eadie Brian J. , Herche Lynn R.
Published: March 2010

Dissolved organic matter (DOM) in aquatic systems is known to reduce the bioavailability of heavy metals. Recent studies have shown similar reductions in bioavailability of organic contaminants. The mechanism for reduction, with Aldrich humics, was to reduce the freely dissolved, bioavailable, xenobiotic concentration by partitioning to DOM. This mechanism was also found to apply to organic contaminants in the presence of DOM from interstitial waters. A reverse-phase separation technique was used to measure the sorbed xenobiotic, and by difference from the total, the freely dissolved concentration of a contaminant permitting the calculation of a partition coefficient (Krp). Equilibrium partitioning of selected polycyclic aromatic hydrocarbon and poly-chlorinated biphenyl congeners to the DOM, in interstitial waters from several geographical sources, ranged over several orders of magnitude for a single compound. The reduction in bioavailability was measured by reduction in the conditional uptake rate constant for organic xenobiotics in the presence of DOM, for the amphipod Pontoporeia hoyi (the major benthic invertebrate in the Great Lakes). Reduction in the conditional uptake rate constant versus controls was used to calculate a biologically determined partition coefficient (Kb). The log Krp was well correlated with log Kb, log Kb = 1.54(0.15) + 0.723(0.03) log Krp (r2 = 0.74, n = 195) over a range of three orders of magnitude in measured partition coefficient for individual compounds using DOM from different sources.
Uptake and excretion of zinc by several tissues of the lobster (Homarus Americanus)
Authors: Waiwood B. A. , Zitko V. , Haya K. , Burridge L. E. , Mcleese D. W.
Published: March 2010

Lobsters, Homarus americanus, were exposed in a flow-through system to a sublethal concentration of zinc (Zn++) for 4 d and then transferred to flowing unspiked sea water for 7 d. The concentrations (μg/g dry weight) of Zn++ after the four days of exposure were in the order gill > green gland > haemolymph > hepatopancreas > crusher tissue > crusher muscle > pincer tissue > shell > testes > heart > pincer muscle > abdominal (tail) muscle. After 7 d in unspiked water the concentration of Zn++ in each of the tissues decreased, but did not return to pre-exposure levels. In terms of the total tissue burden the level of Zn++ in only the hepatopancreas continued to increase during the depuration phase. The data were analysed using a four-compartment model with haemolymph as the “central” compartment. The exchange of Zn++ between gills and water was rapid, between gills and haemolymph was somewhat slower, and between haemolymph and tail muscle was extremely slow.
Avoidance behavior of mallards and northern bobwhite exposed to carbofuran-contaminated food and water
Authors: Kononen D. W. , Hochstein J. R. , Ringer R. K.
Published: March 2010

Food and water avoidance experiments were conducted on mallards (Anas platyrhynchos L.) and northern bobwhite (Colinus virginianus L.) exposed to a range of dietary carbofuran concentrations. A dietary avoidance concentration 50 (analogous to an LC50) was calculated for each avoidance experiment. This statistic describes the dietary toxicant concentration threshold at which, when exceeded, exposed animals are likely to discriminate between untreated and treated feed or water. The food avoidance concentration 50s (FAC50s) for mallards and bobwhite were 10 and 159 ppm, respectively. The water avoidance concentration 50 (WAC50) for mallards was 3 ppm. For bobwhite the WAC50 for carbofuran was estimated to exceed 50 ppm.
In situ variations in oyster mutagenicity and tissue concentrations of polycyclic aromatic hydrocarbons
Authors: Pittinger Charles A. , Buikema Arthur L. , Falkinham Joseph O.
Published: March 2010

Variations in oyster mutagenicity were monitored in a series of in situ relocation experiments and compared with tissue concentrations of polycyclic aromatic hydrocarbons (PAHs). Oysters (Crassostrea virginica) were relocated among three rivers in the southern Chesapeake Bay and sampled over a 2-week exposure period. Extracts of oyster tissues were assayed for mutagenic activity by the Salmonella typhimurium microsomal test and analyzed for selected PAHs by gas chromatography. Oysters relocated to the polluted Elizabeth River (Norfolk, VA) from a pristine site (Ware River, VA) accumulated mutagenic activity and PAHs within 3 d following relocation. Mutagenicity increased over a 14-d period while tissue levels of most PAHs stabilized or declined after 3 d. Extracts of native oysters from the Elizabeth River exhibited comparable levels of mutagenic activity as 14-d relocated oysters. In elimination experiments, PAH levels and mutagenic activity of Elizabeth River oysters decreased following relocation to the Ware River and were not detected after 14 d. Regression analyses did not detect a significant association between slopes of mutagenicity dose-responses and tissue levels of PAHs. Marginal associations with numbers of Salmonella revertants per plate were detected in comparisons with sums of PAH tissue levels, and with tissue levels of benzofluoranthene.
Detection of a microbial consortium, including type II methanotrophs, by use of phospholipid fatty acids in an aerobic halogenated hydrocarbon-degrading soil column enriched with natural gas
Authors: Nichols Peter D. , Antworth Christopher P. , Parsons John , White David C. , Henson J. Michael , Wilson John T.
Published: March 2010

The phospholipid ester-linked normal and lipopolysaccharide layer hydroxy fatty acids from microbes in a natural gas (85% methane)-stimulated soil column capable of degrading halogenated hydrocarbons were analyzed in detail by capillary column GC-MS. Microbial biomass, calculated from phospholipid fatty acid (PLFA) concentrations to be 5.6 × 109 bacteria/g (dry weight), was greater in the hydrocarbon-degrading column than in either an azide-inhibited soil column or an untreated surface soil. Microbial community structure information, using GC-MS analysis of derivatized monounsaturated PLFA, indicated that the major component (16 to 28%) of the PLFA in the hydrocarbon-degrading column was the PLFA 18:1δ10c. This novel PLFA has been reported as a major component in type II methanotrophs. The high relative proportions of C18 components relative to C16 fatty acids indicated that type II rather than type I methanotrophs were the most abundant microbial flora present in the active soil column. Fatty acids from other bacterial groups and microeukaryotes also were detected in the hydrocarbon-degrading soil column. Differences between the relative proportions of these metabolic groups of microorganisms were quantified and compared among the three soils analyzed. Based on these differences, the potential exists to use these methods to monitor shifts in microbial biomass and community structure in aquifers where indigenous bacteria are stimulated to biotransform pollutant compounds.
Comparison of laboratory toxicity test results with responses of estuarine animals exposed to fenthion in the field
Authors: Clark James R. , Borthwick Patrick W. , Goodman Larry R. , Patrick James M. , Lores Emile M. , Moore James C.
Published: March 2010

Acute, lethal effects of fenthion (an organophosphate insecticide) on mysids (Mysidopsis bahia), grass shrimp (Palaemonetes pugio), pink shrimp (Penaeus duorarum) and sheepshead minnows (Cyprinodon variegatus) were determined in laboratory tests and after field applications. Exposures at four field sites ranged from short-term exposures (12 h or less) of rapidly decreasing fenthion concentrations to extended intervals (more than 72 h) with slowly increasing or decreasing fenthion concentrations. Laboratory-derived LC50s provided a reliable benchmark for predicting acute, lethal effects of fenthion on caged animals in the field when exposures persisted for 24 h or more but overestimated the toxicity for exposures of less than 24 h. Laboratory pulse-exposure tests with rapidly changing concentrations for 12 h were predictive of the nonlethal and lethal effects observed for short-term field exposures.
Fate and movement of azaarenes and their anaerobic biotransformation products in an aquifer contaminated by wood-treatment chemicals
Authors: Pereira Wilfred E. , Rostad Colleen E. , Updegraff David M. , Bennett Jon L.
Published: March 2010

Infiltration of wastes containing creosote and pentachlorophenol from surface impoundments at an abandoned wood-treatment facility near Pensacola, Florida, resulted in contamination of the underlying sand and gravel aquifer. Pond sludges and sediments near the source were contaminated with 2- to 5-ring azaarenes having log Kow values of from 2.0 to 5.6. However, the ground water contained only azaarenes and their oxygenated and methylated derivatives having log Kow values of less than 3.5. These compounds also were present in coal tar-contaminated ground water at a site near St. Louis Park, Minnesota.

Laboratory anaerobic degradation studies and on-site observations indicated that oxygenated azaarenes probably were biotransformation products of reactions mediated by indigenous microbial populations. Microbial N-methylation, C-methylation and O-methylation reactions are reported here for the first time. In the presence of nutrients and carbon sources such as acetate and propionate, all azaarenes studied were either partially or completely degraded. Evidence for the microbial degradation of azaarenes in ground water from anaerobic zones is presented. Oxygenated azaarenes were relatively more water-soluble, mobile and persistent in hydrogeologic environments.
Chronic effects of DI-2-ethylhexyl phthalate on biochemical composition, survival and reproduction of Daphnia magna
Authors: Knowles Charles O. , McKee Michael J. , Palawski Donald U.
Published: March 2010

Daphnia magna Straus were exposed for 21 d to 0, 12, 27, 72, 158 and 811 μg/L di-2-ethylhexyl phthalate (DEHP). On days 7 and 21 of exposure, levels of protein, RNA, DNA, glycogen and total lipid were determined and related to effects on survival and reproduction. The maximum allowable toxicant concentration based on survival and reproduction was between 158 and 811 μg/L DEHP. However, survival and reproduction were not the most sensitive parameters measured. A no observed effect concentration of 72 μg/L was identified by DNA content per individual on day 7, by RNA/DNA ratio on day 7 and by surfacing behavior of Daphnia on day 0. Reduced protein growth was associated with increased RNA/DNA and protein/RNA/DNA ratios. Glycogen was the only biomolecule affected in Daphnia exposed to 811 μg/L DEHP for 21 d.