bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rainbow trout liver activation systems with the ames mutagenicity test
Authors: Johnson B. Thomas 
Published: March 2010

Abstract
A poikilothermic metabolic activation system developed from liver homogenate of rainbow trout (Oncorhynchus mykiss, formerly Salmo gairdneri) was used in the Ames Salmonella/Mammalian Microsome Mutagenicity Test. Postmitochondrial fractions (S9) mediated four model promutagens – 2-aminoanthracene (2AA), 2-aminofluorene (2AF), benzo[a]pyrene (BaP) and 3-methylcholanthrene (3MC)–that require two different exogenous metabolic activation routes to form mutagens with Salmonella TA98 and TA100. The enzymatic activity of trout S9 was cytochrome P-450-like; it was heat labile and oxygen- and cofactor-dependent. Preincubation temperature significantly influenced the sensitivity of the fish-activated Ames test. Bacterial mutagenesis with trout activation significantly decreased as preincubation temperature increased; the optimum S9 activation temperature range for trout was 10 to 15°C compared with 37°C for the rat. The liquid-preincubation test was best adapted to the trout poikilothermic activation system; it was significantly more sensitive than the plate-incorporation test in detecting histidine revertants. The S9 activity of trout and rat was qualitatively similar in the Ames test: that is, both fractions metabolically activated 2AA, 2AF, BaP and 3MC to produce bacterial mutagenesis with Salmonella TA98 and TA100. The use of this ecologically relevant exogenous activation system in the short-term predictive genotoxicity testing of freshwater ecosystems is helpful in the assessment of potential hazards of chemical contaminants on fishery resources.
Anaerobic microbial degradation of acridine and the application of remote fiber spectroscopy to monitor the transformation process
Authors: Knezovich John P. , Bishop Dorothy J. , Kulp Thomas J. , Grbić-Galić Dunja , Dewitt John 
Published: March 2010

Abstract
Anaerobic microbial transformation of a polynuclear nitrogen heterocycle, acridine, was studied in laboratory microcosms with three different inocula: a stabilized, mixed culture growing on ferulic acid that was originally enriched from anaerobic sewage sludge, and sulfate-reducing and methanogenic aquifer materials from two sites at a groundwater aquifer contaminated by landfill leachate. Acridine degradation was investigated under methanogenic, denitrifying and sulfate-reducing conditions at concentrations of 1 to 6 μg/ml. Substrate degradation was followed using two standard analytical techniques (HPLC and GC-MS) and a new, in situ remote fiber spectroscopic (RFS) technique. This RFS was used successfully to follow changes in concentration of acridine with time, which indicates the technique has a significant potential for monitoring the degradation process in environmental media. Acridine was degraded extensively in one to three weeks under each of the conditions studied. A range of heterocyclic, homocyclic aromatic and aliphatic intermediates was identified by GC-MS analyses. On the basis of these compounds, a tentative route of anaerobic acridine transformation is proposed that begins with oxidation and proceeds through the common degradative route for oxidized aromatic compounds.
Sorption of organic acid compounds to sediments: Initial model development
Authors: Jafvert Chad T. 
Published: March 2010

Abstract
The adsorption to sediments and saturated soils of selected organic acid compounds was examined as a function of compound and sediment properties. Intrinsic compound properties examined included the dissociation constant (pKa) and hydrophobic character. Properties of the sediment examined included ionic strength and composition, organic carbon content and aqueous phase pH. By varying these properties, adsorption of both the neutral and anionic forms of these compounds was shown to occur. Adsorption of the neutral species occurs similarly to that of other hydrophobic compounds that do not contain acidic functional groups. Adsorption of the anionic species was influenced, however, by intrinsic chemical as well as electrostatic factors. Adsorption of the anionic species to a specific sediment was modeled as a linearly dependent function of pH. Compounds used in this study included 2,4-dinitro-o-cresol (DNOC), 2-(2,4,5-trichlorophenoxy)propanoic acid (silvex), pentachlorophenol (PCP), 4-chloro-α-(4-chlorophenyl)benzeneacetic acid (DDA) and 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB).
Lipid-partitioning and disposition of benzo[a]pyrene and hexachlorobiphenyl in lake michigan Pontoporeia hoyi and Mysis relicta
Authors: Gardner Wayne S. , Landrum Peter F. , Cavaletto Joann F. 
Published: March 2010

Abstract
Two Lake Michigan macroinvertebrates, Pontoporeia hoyi and Mysis relicta, exhibited major differences in the disposition of the lipophilic contaminants, [3H]benzo[a]pyrene (BaP) and [14C]2,4,5,2′,4′,5′-hexachlorobiphenyl (HCB). Interactions of these contaminants with major lipid classes (triacylglycerols and phospholipids) were examined by centrifuging aqueous whole organism homogenates of labeled animals into three discrete layers that were operationally defined as “buoyant-lipid,” “particle” and “aqueous” fractions. The buoyant-lipid fraction contained most of the energy storing triacylglycerols, whereas the particle and aqueous fractions contained most of the membrane phospholipids. During 2 to 4 d experiments, unmodified BaP and HCB partitioned among the three fractions in proportion to the distribution of total-lipids in both species, but in M. relicta most of the BaP was biotransformed into polar metabolites that were selectively found in the aqueous and particle fractions. Apparently HCB was not substantially biotransformed in either species but took longer (ca. 2 d) to reach steady state among lipid pools in M. relicta than it did in P. hoyi (&lt; 1 d). Although the contaminants did not always completely reach steady state in the organisms with respect to the external environments during these relatively short experiments, they appeared to reach steady state among lipid pools within the organisms.
Aquatic toxicity testing using the nematode,Caenorhabditis elegans
Authors: Williams Phillip L. , Dusenbery David B. 
Published: March 2010

AbstractA promising aquatic toxicity test has been developed using a species of free-living nematode, Caenorhabditis elegans. The testing was performed with soluble forms of Ag, Hg, Cu, Be, Al, Pb, Cr, As, Tl, Zn, Cd, Ni, Sr and Sb. The LC50 values for 1 to 4 d of exposure were determined and compared to the published invertebrate data. With Caenorhabditis elegans Pb, Cr and Cd were found to have the lowest 96-h LC50 (0.06 mg/L) and Sr had the highest LC50 (465 mg/L). All the metals except As have a significantly lower 96-h LC50 (from 20 to 15,000 times lower) than 24-h LC50. Comparison with published data for other invertebrates indicated that Caenorhabditis elegans was more sensitive to Pb, Cr and Be and less sensitive to As than any of the other organisms that have been tested. Given the ease in culturing and the extensive knowledge of the basic biology of Caenorhabditis elegans, coupled with the ecological abundance of nematodes, the method is worthy of further study to determine its usefulness as an aquatic test species.
Acute toxicity of isomers of the pyrethroid insecticide deltamethrin and its major degradation products to Daphnia magna
Authors: Day Kristin E. , Maguire R. James 
Published: March 2010

Abstract
The acute toxicities (4-h, 24-h and 48-h) of eight stereoisomers and four major breakdown products of deltamethrin to D. magna were determined. Parent deltamethrin (isomer 1) was the most toxic, with EC50 values in the range of 0.05 to 1.75 μg/L, concentrations that have been observed in the surface microlayer and subsurface water in field studies. The other three isomers (2-, 3- and 4-deltamethrin) were two- to tenfold less toxic than 1-deltamethrin. Isomers 1′, 2′, 3′ and 4′ plus the four breakdown products studied displayed no significant toxicity. Because 1-deltamethrin can be converted in natural water to 2′-, 3- and 4′- deltamethrin, and because 3-deltamethrin is toxic to D. magna, this isomerization is only a partial detoxification step as far as some aquatic organisms are concerned.
Disposition and metabolic fate of benzo[a]pyrene in the brown bullhead
Authors: Steward A. Ruth , Kandaswami Chithan , Ziper Craig , Rutkowski Joel P. , Sikka Harish C. , Chidambaram S. 
Published: March 2010

Abstract
We have investigated the biological fate of intraperitoneally administered benzo[a]pyrene (BP) in brown bullhead (Ictalurus nebulosus) maintained in flowing water. The tissue distribution of benzo[a]pyrene-derived radioactivity at 24 and 72 h after treatment was determined. The highest concentration of BP-derived radioactivity was in bile (3.7 and 12.3 μg BP equivalents/g bile at 24 and 72 h, respectively). Biliary radioactivity amounted to 16% of the radioactivity found in the fish at 72 h. The major components of bile collected at 72 h were glucuronides (24%), water-soluble conjugates unhydrolyzed by β-glucuronidase or arylsulfatase (57%) and unmetabolized BP (10%). The potentially genotoxic metabolite BP-7,8-dihydrodiol and its glucuronide represented 3% of the radioactivity of the bile at 72 h. High concentrations of BP-derived radioactivity were also present in liver and in kidney (920 and 290 ng equivalents of BP/g at 72 h, respectively). Although only low concentrations of BP-derived radioactivity were detected in muscle (60 ng eq/g at 72 h), the proportion of the BP-derived radioactivity found in this tissue at 72 h amounted to 16% of the radioactivity found in the fish. Unmetabolized BP represented 32% of the muscle radioactivity, and 96% of the radioactivity that could be extracted with ethyl acetate and characterized by HPLC. BP-7,8-dihydrodiol represented 0.2% of the muscle radioactivity. The amount of BP derivatives irreversibly bound to macromolecules and precipitable with trichloroacetic acid at 72 h amounted to 12 to 13% of the radioactivity present in each tissue. Furthermore, 21, 28 and 35% of the BP-derived radioactivity could not be extracted with ethyl acetate from the insoluble components of muscle, kidney and liver, respectively, at 72 h. These data indicate that significant amounts of active metabolic intermediates of BP capable of alkylating DNA and other macromolecules were formed in bullhead tissues.
Preparation of benthic substrates for sediment toxicity testing
Authors: Ditsworth George R. , Schults Donald W. , Jones Jill K. P. 
Published: March 2010

Abstract
A jar rolling apparatus was constructed to prepare test substrates using sediments spiked with laboratory chemicals, the toxicity of which were assessed with the Rhepoxynius abronius bioassay Test sediments were mixed by rolling them for several hours in one gallon glass jars Mixing was considered adequate based on the analytical results of sediment samples that were collected at locations along the longitudinal axis within each horizontally lying jar immediately after rolling However, because comparative standards did not exist, definitive conclusions of mixing thoroughness could not be drawn Coefficients of variation, used to assess mixing within jars, were 11.5% or less (mean 5.1%) Mixing was not significantly different among replicated jars but, in some jars, was significantly different among within jar sample locations
Acute avoidance reactions and behavioral responses of juvenile rainbow trout (Oncorhynchus mykiss) to garlon 4®, garlon 3A® and vision® herbicides
Authors: Morgan John D. , Vigers Gary A. , Farrell Anthony P. , Janz David M. , Manville John F. 
Published: March 2010

Abstract
Laboratory bioassay experiments were conducted with juvenile rainbow trout (Oncorhynchus mykiss) to determine the acute lethal (96-h LC50) values of the forest-use herbicides Garlon 3A®, Garlon 4®, and Vision® with 15% and 10% surfactant formulations, and the threshold concentrations of these herbicides that would cause behavioral effects. A Y-maze apparatus was used to determine the threshold concentration of each herbicide that elicited either an avoidance or a preference reaction from rainbow trout fry after a one-hour exposure period. Rainbow trout fry were observed for qualitative behavioral changes (e.g., increased coughing and ventilatory rates, loss of equilibrium, etc.) over a four-day period of exposure to a wide range of chemical strengths. Nominal concentrations of the herbicides eliciting threshold avoidance reactions in test fish were 150 ppm Vision-10% surfactant, 54 ppm Vision-15% surfactant, 19.2 ppm Garlon 4, and 800 ppm Garlon 3A, which were, respectively, 2, 2, 8, and 2 times the 96-h LC50 values determined for each herbicide. Preferential reactions to the herbicide solutions were not observed. Qualitative behavioral changes were observed in rainbow trout fry at levels from 25% (Garlon 4) to 50% (Garlon 3A, Vision-10% and -15% surfactants) of the 96-h LC50 values. Nominal concentrations of the herbicides causing threshold changes in fish behavior were 37.5 ppm Vision-10% surfactant, 13.5 ppm Vision-15% surfactant, 0.60 ppm Garlon 4, and 200 ppm Garlon 3A.
Effects of dissolved organic carbon on accumulation and acute toxicity of fenvalerate, deltamethrin and cyhalothrin to Daphnia magna (straus)
Authors: Day Kristin E. 
Published: March 2010

Abstract
The effects of dissolved organic carbon (DOC) in the form of Aldrich humic acid on the accumulation and acute toxicities of three synthetic pyrethroids — fenvalerate, deltamethrin, and cyhalothrin—to Daphnia magna in laboratory experiments were investigated. Concentrations of DOC as low as 2.6 mg/L, 3.2 mg/L, and 3.1 mg/L for deltamethrin, fenvalerate, and cyhalothrin, respectively, resulted in a significant decrease in bioaccumulation. Acute toxicities of all three pyrethroids were found to decrease as DOC concentrations increased; e.g., at a DOC concentration of 15.5 mg/L, the acute toxicity of fenvalerate was reduced by a factor of 17. The percentages of deltamethrin and fenvalerate bound to DOC increased as DOC concentrations increased after 2-h and 24-h contact times. At low concentrations of DOC (e.g., 1.7 mg/L), as much as 40% of fenvalerate and 20% of deltamethrin were found sorbed to the dissolved material. After 24-h contact times, 76.4 and 80.8% of fenvalerate and deltamethrin, respectively, were bound to DOC. Reverse-phase partition coefficients (Krp) for both fenvalerate and deltamethrin were found to vary with DOC concentrations and were in the range 1.0 to 4.8 × 105 L/kg for fenvalerate and 0.9 to 5.6 × 105 L/kg for deltamethrin.
Environmental factors affecting toluene degradation in ground water at a hazardous waste site
Authors: Armstrong Anthony Q. , Hodson Robert E. , Hwang Huey-Min , Lewis David L. 
Published: March 2010

Abstract
The microbial ecology of pristine and contaminated ground water at a chemical waste disposal site was investigated. Recently, it was determined that ground water downslope from the disposal site contained elevated levels of toxic pollutants, including benzene, toluene, xylene and methylene chloride, as well as iron and manganese. Microbial mineralization and uptake of radiolabeled glucose and amino acids indicated a metabolically active microflora in both pristine (upslope from the contamination) and contaminated groundwater samples collected from monitoring wells at the site. However, microbial uptake and mineralization of glucose and amino acids were up to fourfold slower in the contaminated well water than in the control well. Rates of mineralization and uptake of toluene were easily measurable in water from the contaminated well but were negligible in water from the pristine well, suggesting that the subsurface microflora in the contaminated region had adapted to degrade toluene. Additions of the inorganic nutrients N, K and P enhanced toluene mineralization in water from the contaminated well, with the addition of K and P enhancing mineralization twofold. The addition of these inorganic nutrients, therefore, presents an opportunity for biorestoration of the site. An increase in the incubation temperature also enhanced toluene mineralization; however, manipulations of pH and dissolved oxygen concentration had no measurable effects.
Critical period of sensitivity to petroleum toxicity in the chicken embryo
Authors: Couillard Catherine M. , Leighton Frederick A. 
Published: March 2010

Abstract
Microliter amounts of South Louisiana crude oil (SLCO) or Prudhoe Bay crude oil (PBCO) were applied to the shell of fertile leghorn chicken eggs on day 8, 8.5 or 9 of incubation. Percent mortality and prevalence of grossly visible lesions were evaluated 96 h after treatment. The 96-h LD50s of SLCO at 8, 8.5 and 9 d of incubation were 2.6, 4.3 and 34.3 μl, respectively. Five μl PBCO caused nearly 100% mortality in 8 and 8.5-d-old embryos, while 12 μl caused 32% mortality in 9-d-old embryos. Liver necrosis, edema and increases in body weight and in the ratio of body weight to crown-rump length were found in embryos treated on day 8, 8.5 or 9 of incubation with either SLCO or PBCO. The 16-fold decrease in sensitivity of the embryo from day 8 to day 9 of incubation suggests that the chorioallantoic membrane may be important in the toxic action of petroleum oil.
Degradation and bound residue formation of atrazine in a Western Tennessee soil
Authors: Winkelmann D. A. , Klaine S. J. 
Published: March 2010

Abstract
Biological and physical degradation, and metabolite and soil-bound residue formation, of [U-ring-14C]atrazine (2-chloro-4-[ethylamino]-6-[isopropylamino]-1,3,5-triazine) were characterized in a western Tennessee soil using laboratory and field assays. Biological mineralization of [14C]atrazine was examined in the laboratory using intact surface soil cores in sealed microcosms. Physical mineralization was determined using gamma-radiation-sterilized soil microcosms. Metabolites measured were deethylatrazine (DEA), deisopropylatrazine (DIA), dealkylatrazine (DAA) and hydroxyatrazine (HYA). Atrazine was applied at a rate of 2.2 kg/ha (˜ 5.6 μg/g soil) to soil microcosms in two studies and 3.2 kg/ha to the field. Evolution of 14CO2 from [14C]atrazine in nonirradiated soil microcosms increased to 12 and 28% of the radiolabel added after 180 d incubation. Irradiated soil microcosms evolved less than 0.07% of the radiolabel as 14CO2 for both studies after the same period. The concentrations of metabolites throughout the laboratory and field studies were: HYA &gt; DEA &gt; DIA &gt; DAA. The highest concentration of HYA detected during microcosm and field studies was approximately 0.5 μg/g soil. Atrazine dissipation rates and metabolite production in nonirradiated microcosms were comparable to field results. Atrazine concentrations after 180 d in nonirradiated microcosm and field samples were lower than HYA, and either equivalent to or greater than DEA. The DAA was not detected throughout microcosm or field studies. Rates of dissipation for atrazine followed first-order kinetics. Atrazine half-life, based on extractable residues, was approximately 21 d in the microcosm studies, compared to 14 d in surface field soil. Extractable 14C residues sampled from nonirradiated microcosms decreased in concentration during the incubation period. Soil-bound 14C residues increased and, at the termination of the two studies, accounted for 39 and 43% of the radioactivity added to nonirradiated microcosms. Bound 14C residues in irradiated microcosms accounted for 49 and 48% of the activity after 180 d. Similarity of results between microcosm and field studies suggests that those microcosms may be useful for predicting the fate of atrazine in surface soil.
Decreased survival of rainbow trout exposed to no. 2 fuel oil caused by sublethal preexposure
Authors: Steadman B. L. , Stubblefield W. A. , Lapoint T. W. , Bergman H. L. , Kaiser M. S. 
Published: March 2010

Abstract
Rainbow trout (Oncorhynchus mykiss) were exposed for 21 d to sublethal levels of No. 2 fuel oil (2FO). The four exposure concentrations ranged from 12 to 100 mg/L 2FO dispersed in water and resulted in 0 to 12% mortality. Following this exposure period (preexposure) the ability of preexposed trout to survive exposure to acutely lethal levels of 2FO was observed. Preexposure to either 50 or 100 mg/L 2FO consistently resulted in decreased survival and a lower LC50 for a given observation period. Unfortunately, because the LC50 determinations were not obtained independently, they could not be used to test statistically the effects of preexposure on survival. Therefore, two proportional hazard modeling techniques were applied to the data to test for effects due to preexposure. Both modeling techniques indicated that preexposure results in decreased survival of rainbow trout exposed to acutely toxic levels of 2FO. Thus, in contrast to preexposure to metals, which results in acclimation, preexposure to 2FO results in decreased survival.
Effects of sediment-bound endosulfan on survival, reproduction and larval settlement of meiobenthic polychaetes and copepods
Authors: Chandler G. Thomas , Scott Geoffrey I. 
Published: March 2010

Abstract
Endosulfan-contaminated muddy sediments were collected from a tidal creek bottom after rain runoff from an agricultural watershed and tested for their effects on larval settlement/growth, survival and reproduction of cultured meiobenthic polychaetes and copepods. Endosulfan (ES) strongly inhibited larval colonization and early juvenile growth of the cosmopolitan, euryhaline polychaete Streblospio benedicti. In laboratory microcosms, ES concentrations as low as 50 μg·kg−1 sediment significantly reduced the number of larval colonists by &gt;50% relative to ES-free control sediments. Higher concentrations closer to actual field levels suppressed Streblospio benedicti colonization completely. Early growth of newly metamorphosed juveniles was depressed 36 and 40% relative to controls at ES concentrations of 50 and 100 μg·kg−1, respectively. In contrast, when the common benthic harpacticoid copepod Pseudobradya pulchella was chronically exposed to sediment ES as high as 200 μg·kg−1, survival and egg production were unaffected despite many examples of high ES toxicity to other crustaceans. Of more than 1,600 Pseudobradya pulchella tested, more than 95% survived ES concentrations of at least 200 μg·kg−1, and over 98% of 1,200 females produced normal clutches of eggs. Similarly, survival of another common benthic copepod, Nannopus palustris, was not significantly affected below a threshold concentration of 200 μg·kg−1 ES. At 200 μg·kg−1, however, Nannopus palustris' survival was significantly reduced relative to control and 50-μg·kg−1 ES treatments.
Acute and long-term toxicity of water-soluble cationic polymers to rainbow trout (Oncorhynchus mykiss) and the modification of toxicity by humic acid
Authors: Goodrich Mark S. , Dulak Linda H. , Friedman Marvin A. , Lech John J. 
Published: March 2010

Abstract
The toxicity of two classes of cationic polymers, epichlorhydrin/dimethylamine polyamines and quaternary amine copolymers, were investigated. Static bioassays of those polymers resulted in LC50 concentrations ranging from 271 μg/L to 1,733 μg/L. Under flow-through conditions the toxicity was 1.7 to 13.9 times greater, depending on the polymer used. Using a reference humic acid along with the polymers in toxicity studies, strong correlations were established between humic acid concentration and LC50. Even at a fairly low humic acid concentration (5 mg/L), the toxicity of the polymers was reduced 7- to 16-fold. At higher humic acid concentrations (50 mg/L), cationic polymer toxicity was reduced 33- to 75-fold.