bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potential impact of selected agricultural chemical contaminants on a northern prairie wetland: A microcosm evaluation
Authors: Johnson B. Thomas 
Published: March 2010

AbstractAn aquatic, multicomponent microcosm simulating a northern prairie wetland was used to assess the potential effects of six extensively used agricultural pesticides on this important wildlife habitat. Using a nested experimental design, 16 4-liter aquatic microcosms were treated with three concentrations of each of the pesticides carbofuran, fonofos, phorate, atrazine, treflan and trial-late. The microcosm units were incubated for 30 d in an environmental chamber, with a 16-h light:8-h dark cycle, maintained at 20°C. Specific limnological, biological and toxicological parameters were monitored over time by observing the interactions of water, animals, sediment and plants with the pesticides. The laboratory protocol was designed as an initial, rapid, economical screening test to determine the effect, but not the fate, of chemical contaminants in terms of toxicity, impaired productivity and community biochemical functions.Static acute toxicity tests with Daphnia magna and Chironomus riparius suggested that carbofuran, fonofos, phorate and triallate were very toxic to aquatic invertebrates. For D. magna the 48-h EC50 values were 48, 15, 19 and 57 μg/L, respectively. Invertebrate viability tests indicated rapid changes in the toxicological persistence of these pesticides after microcosm interaction. Populations of D. magna were established in the 10 μg/L test concentration of carbofuran, phorate, triallate and fonofos at 1, 1, 14 and 28 d, respectively. Preexposure of the wetland sediments to either triallate or fonofos did not appear to change the relative toxicological persistence of each compound in the water column. Changes in pH, alkalinity, conductivity, dissolved oxygen, total nitrogen and total phosphorus were also observed with different pesticide treatments. Atrazine significantly reduced gross primary productivity and inhibited algal and macrophytic growth. In general, there was no evidence of significant inhibition of microbial functions in the water or hydrosoil of the treated microcosms. The respiratory electron transfer system, phosphatase activity, oxygen consumption and mineralization of dissolved organic carbon were not significantly impacted by any of these pesticides in hydrosoils. However, the impact of atrazine, fonofos and triallate on invertebrates and plants in the microcosm—both key elements in wetland productivity—would suggest that caution be used in application of these pesticides in or near wetland habitats.
Characterization of chemical waste site contamination and determination of its extent using bioassays
Authors: Thomas J. M. , Skalski J. R. , Cline J. F. , McShane M. C. , Simpson J. C. , Miller W. E. , Peterson S. A. , Callahan C. A. , Greene J. C. 
Published: March 2010

Abstract
Bioassays were used in a three-phase research project to (a) assess the comparative sensitivity of test organisms to known classes of chemicals, (b) determine if the chemical components in field soil and water samples of unknown chemical composition could be inferred from laboratory studies using pure chemicals and (c) investigate kriging (a relatively new statistical “mapping” technique) and bioassays as methods to define the areal extent of chemical contamination.
The algal assay generally was most sensitive to samples of pure chemicals, soil elutriates and water from eight sites with known chemical contamination. Bioassays of nine samples of unknown chemical composition from the Rocky Mountain Arsenal site showed that a lettuce seed soil contact phytoassay was most sensitive. Preliminary evidence suggests that bioassays might be a useful tool in broadly identifying classes of toxic components of contaminated soil. Nearly pure formulations of insecticides and herbicides were less toxic than were their counterpart commercial formulations. This finding indicates that chemical analysis alone may fail to correctly rate the severity of possible environmental toxicity. Finally, we demonstrate that the lettuce seed phytoassay and kriging techniques can be used to map contamination in a portion of the Rocky Mountain Arsenal site and aid in cleanup decisions.
Role of artificial burrows inHexageniatoxicity tests: Recommendations for protocol development
Authors: Henry M.G. , Chester D.N. , Mauck W.L. 
Published: March 2010

AbstractHexagenia 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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.