bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

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

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

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

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

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

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

Abstract
The value of hexavalent chromium as a reference toxicant was investigated by comparing the precision of two laboratories in preparing test solutions, examining the consistency of chromium exposure in the test chambers during experiments and determining the effect of nominal versus measured test concentrations on the calculated toxicity (EC50 or LC50). The sensitivities of the test animals to chromium were also determined.
The coefficients of variation associated with preparing chromium test concentrations were 51 and 63.8% in salt and fresh water, respectively, at one laboratory, and 136 and 14.8%, respectively, at the other laboratory. Hexavalent chromium remained stable in the hexavalent (as prepared) form during the toxicity test, with recoveries ranging from 77 to 114%. The precision of the analytical laboratory in measuring chromium-spiked fresh and salt waters ranged from 0.2 to 9.1%. The impact on the calculated EC50s or LC50s of using analytically measured versus nominal concentrations in the analyses was negligible. A comparison of seven species in 27 tests showed organism sensitivity (mean EC50 or LC50 as mg/L Cr6+) to chromium to be, in decreasing order of sensitivity: Ceriodaphnia sp. (0.031), Daphnia pulex (0.086), Mysidopsis almyra (5.1), Mysidopsis bahia (6.03), Cyprinodon variegatus (21.4), Pimephales promelas (26.1) and Lepomis macrochirus (182.9).
The 48-h LC50s for M. bahia were not significantly different (p &lt; 0.05) either within or between laboratories during a 3-week study; values ranged from 5.49 to 7.72 mg/L Cr6+ in both laboratories (nominally) and from 4.21 to 7.23 mg/L Cr6+ when analytically verified by an independent laboratory. The acute toxicities of chromium to D. pulex differed significantly between laboratories, by almost one order of magnitude. Interlaboratory variability observed in D. pulex tests was attributed to differences in the test organisms' food. As reference toxicant tests, chromium tests are valuable benchmark indices of the relative health of test organisms over time or among laboratories. When toxicity test information is used in critical decision making, such as compliance with effluent permit limitations, a reference toxicant such as chromium contributes to quality control and assurance.
Predictive models for photoinduced acute toxicity of polycyclic aromatic hydrocarbons to Daphnia magna, strauss (cladocera, crustacea)
Authors: Newsted John L. , Giesy John P. 
Published: March 2010

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

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

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

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

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

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

Abstract
Hepatic aryl hydrocarbon hydroxylase (AHH) was measured in lake trout (Salvelinus namaycush) from areas on the Great Lakes and from a small “control” lake in a Provincial Park. The results indicated a geographical distribution of MFO activity in the Great Lakes corresponding to levels of organic chemical contamination. Lake trout from the industrialized area of western Lake Ontario had a 6 to 62-fold-higher enzyme activity compared to all other sites.
A seasonal variation in mixed-function oxidase activity occurred in the two-year study. The AHH activity decreased sharply in the autumn at spawning and increased thereafter. No correlation was found between the sex, age, or size of lake trout and their AHH activities at any location.
This field study demonstrated the utility of measuring MFO activity in lake trout for monitoring biologically meaningful levels of polyaromatic hydrocarbons and chlorinated hydrocarbons in contaminated environments on the Great Lakes.
Day-night differences in volatilization rates of polychlorinated biphenyls from water to air
Authors: Okla Lennart , Larsson Per 
Published: March 2010

Abstract
The transport rate of polychlorinated biphenyls (PCBs) from water to air was followed in a large (50-m3) artificial pond. The transport rate across the water/air interface during the day exceeded the rate at night and was positively correlated to air temperature. Volatilization is probably responsible for the PCB transfer.