bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods for growth inhibition toxicity tests with freshwater algae
Authors: Nyholm Niels , Källqvist Torsten 
Published: March 2010

Abstract
A critical review of batch-culture freshwater algal toxicity test methods (algal growth inhibition tests) is presented. Interlaboratory comparisons have revealed that the results from such tests can vary a great deal, in some cases by more than three orders of magnitude. The potential causes of variability are the physical/chemical experimental parameters. Algal tests, however, need not be very strictly standardized in order to be reproducible if tests are appropriately conducted and the experimental parameters are understood and controlled. Many algal toxicity data reported in the literature seem to have been generated from tests performed with an excessively high biomass and under poor gas-exchange conditions, the combination of which will cause an insufficient supply of carbon dioxide leading to high pH levels and sometimes even to mass-transport (carbon dioxide)-limited linear growth. Poor gas-exchange conditions will prevail unless the test flasks are shaken or aerated continuously. Literature data on the toxicity of chemicals to algae should therefore be used only with careful evaluation of the test method involved.
Photolysis of picloram in dilute aqueous solution
Authors: Woodburn Kent B. , Fontaine Donald D. , Bjerke E. Lee , Kallos George J. 
Published: March 2010

Abstract
The photolysis of [2,6-14C]pyridine-labeled picloram (4-amino-3,5,6-trichloro-2-pyridine carboxylic acid) was studied at 25°C in sterile, buffered water at pH 7 and in a natural water sample taken from a forest ecosystem. The first-order half-life for picloram photodegradation was the same in both systems, averaging 2.6 d at 25°C for a 40°N latitude location, midsummer time frame. The photolytic decay of picloram in solution produced two major photoproducts. Thermospray liquid chromatography-mass spectrometry (TSP/LC/MS) and gas chromatography/mass spectrometry (GC/MS) in the electron impact and chemical ionization mode were used to elucidate the structures of the photolysis products. The two major 14C-labeled photoproducts were conclusively identified through comparison with analytical standards as oxamic acid (C2H3O4N) and 3-oxo-β-alanine (C3H5O4N).
Relation of hepatic microsomal monooxygenase activity to tissue PCBs in rainbow trout (salmo gairdneri) injected with [14C] PCBs
Authors: Melancon Mark J. , Turnquist Karen A. , Lech John J. 
Published: March 2010

Abstract
The relationship of tissue PCB levels to hepatic microsomal monooxygenase activity in rainbow trout (Salmo gairdneri) was assessed. This was accomplished by injecting individual trout with corn oil vehicle or with a [14C]PCB mixture in corn oil. At 3 to 70 d after injection, tissue [14C]PCB concentrations were determined by scintillation counting of solubilized tissue samples, and hepatic microsomes were prepared and assayed for ethoxyresorufin-O-deethylase and ethoxy-coumarin-O-deethylase activities. At three days after injection only the highest doses of PCBs caused elevation of hepatic microsomal monooxygenase activity. At later times, muscle and liver concentrations of PCBs at or lower than 250 ng/g were associated with hepatic microsomal monooxygenase activity at or near control levels. Elevated hepatic microsomal monooxygenase activity was associated with muscle and liver PCB concentrations 300 ng/g or higher, but not all fish with tissue PCBs above this concentration had elevated hepatic microsomal monooxygenase activity.
Effect of metolachlor on azotobacter nitrogen fixation in soil
Authors: Martinez-Toledo Maria V. , Gonzalez-Lopez J. 
Published: March 2010

Abstract
The effect on nitrogen fixation of 100, 200, 300, 400 and 500 μg metolachlor per gram of soil was studied in nonsterile soil incubated under aerobic conditions and sterilized soil inoculated with Azotobacter chroococcum. Metolachlor at concentrations of 400 and 500 μg/g significantly reduced dinitrogen fixation in nonsterile soil and sterile soil inoculated with Azotobacter sp. However, this inhibitory effect on nitrogenase activity disappeared after 24 h, showing that acrobic diazotrophs populations present in the soil can tolerate high concentration of this herbicide without significant changes in their nitrogenase activity.
Reduced growth and motility of euglena gracilis in the presence of aflatoxin B1 and trichothecene T-2 toxin
Authors: Weekley L. Bruce , O'Rear Charles E. , Kimbrough T. Daniel , Llewellyn Gerald C. 
Published: March 2010

Abstract
The ciliated protozoan, Euglena gracilis, was cultured in the presence of aflatoxin B1 (AFB1) (10, 100, and 1000 ng/ml) or T-2 toxin (10, 100 and 1000 ng/ml) for 6 d. During this period, the control culture size progressively increased, while both AFB1 and T-2 toxin reduced culture size in a dose-dependent manner. The sensitivity of the changes in Euglena gracilis growth rate to AFB1 suggests that this organism may have only limited application as a bioassay. Protozoal motility (as assessed by changes in turbidity) was reduced by both toxins, but not in a dose-dependent manner.
Bioassay of acute toxicity of herbicide mixture dalapon/weedazol 4L on estuarine fauna
Authors: Gillespie Paul A. 
Published: March 2010

Abstract
The acute toxicities of dilutions of a herbicide spray formulation suggested for use in salt-marsh environments to eradicate Spartina sp. have been estimated for six estuarine animal species using two complementary laboratory bioassay procedures. Responses of the test species ranged from highly sensitive for the whitebait (Galaxias maculatus) (2-h LC50 of 0.45% corresponding to active ingredient concentrations of 36, 26 and 6 mg/L for dalapon, amitrole and NH4CNS, respectively) to extremely resistant for the mud crab (Helice crassa) (no mortality during a 4-h exposure after direct spraying with the full-strength mixture). Intermediate levels of toxicity were observed for the cockle (Chione stutchburyi), the mud snails (Amphibola crenata and Potamopyrgus estuarinus) and the estuarine prawn (Palaemon affinis). The results suggest that acute (lethal) effects on estuarine fauna would in most cases be minimal during actual spraying except where animals or shallow-pooled areas covering animals are sprayed directly.
Impact of an episodic event on the toxicity evaluation of a treated municipal effluent
Authors: Lewis M. A. , Eckhoff W. S. , Cooney J. D. 
Published: March 2010

AbstractThe chronic toxicities of a treated municipal effluent and the corresponding receiving water were evaluated for fathead minnows and Ceriodaphnia dubia in standard 7-d toxicity tests. The effluent and river water were not significantly toxic to the fathead minnow based on measurements for survival and weight. Ceriodaphnia survival after 3 d exposure in the controls and five test concentrations ranged from 60 to 100%, but on test day 4, survival was significantly reduced at all test levels including in the controls. The toxicity was attributable to the dilution water, which was river water collected above the WWTP outfall. The toxicant(s) in the dilution water was not identified based on a comparison of the daily chemical analyses. Overall, the utilization of the receiving water for dilution water in the toxicity tests showed the potential of an episodic event to control the quality of biota in the receiving water.
Terrestrial population models for ecological risk assessment: A state-of-the-art review
Authors: Emlen John M. 
Published: March 2010

Abstract
Few attempts have been made to formulate models for predicting impacts of xenobiotic chemicals on wildlife populations. However, considerable effort has been invested in wildlife optimal exploitation models. Because death from intoxication has a similar effect on population dynamics as death by harvesting, these management models are applicable to ecological risk assessment. An underlying Leslie-matrix bookkeeping formulation is widely applicable to vertebrate wildlife populations. Unfortunately, however, the various submodels that track birth, death, and dispersal rates as functions of the physical, chemical, and biotic environment are by their nature almost inevitably highly species- and locale-specific. Short-term prediction of one-time chemical applications requires only information on mortality before and after contamination. In such cases a simple matrix formulation may be adequate for risk assessment. But generally, risk must be projected over periods of a generation or more. This precludes generic protocols for risk assessment and also the ready and inexpensive predictions of a chemical's influence on a given population. When designing and applying models for ecological risk assessment at the population level, the endpoints (output) of concern must be carefully and rigorously defined. The most easily accessible and appropriate endpoints are (1) pseudoextinction (the frequency or probability of a population falling below a prespecified density), and (2) temporal mean population density. Spatial and temporal extent of predicted changes must be clearly specified a priori to avoid apparent contradictions and confusion.
Sorption of nonpolar organic chemicals on low-carbon-content aquifer materials
Authors: Stauffer Thomas B. , Wickman Donald C. , Macintyre William G. 
Published: March 2010

Abstract
Sorption isotherms were measured by batch equilibration methods for three nonpolar organic sorbates on seven subsurface, low-carbon sedimentary aquifer materials. Radiolabeled (14C) 1-methylnaphthalene, o-dichlorobenzene and naphthalene were separately equilibrated with the sorbents to determine sorption coefficients (K). Chemical and physical properties of the aquifer materials were determined.
Possible relationships between sorption coefficients and organic carbon (OC) content and other sorbent properties were investigated using multivariate statistics. Sorbent properties used in the statistical analysis were sorption coefficients, percentage OC, percentage sand, percentage clay, percentage silt, specific surface area, cation exchange capacity, percentage 1:1 clay, percentage 2:1 clay and percentage iron content. No predictive relationships between sorption coefficients and aquifer material properties were found. The sorption coefficient does not correlate with any of the properties of the aquifer materials, including OC content for aquifer materials with OC content of less than 0.10%. It is recommended that sorption coefficients be determined experimentally on each different aquifer material for use in ground water transport calculations.
Toxicity and anaerobic biodegradability of substituted phenols under methanogenic conditions
Authors: O'Connor Owen A. , Young L. Y. 
Published: March 2010

Abstract
Phenol, 2-chlorophenol, 2,4-dimethylphenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 3-methyl-4-chlorophenol (4-chloro-m-cresol) and 2-methyl-4,6-dinitrophenol (4,6-dinitro-o-cresol) were evaluated for their anaerobic biodegradability and toxicity to methanogenesis using two anaerobic bioassays, the biochemical methane potential (BMP) and the anaerobic toxicity assay (ATA). The BMP and ATA were used to evaluate the stoichiometric conversion of added substrate carbon to CO2 and CH4. Each substrate was the only added carbon source (20-200 mg/L) prepared in prereduced defined medium using a 10% (v/v) inoculum of municipal digester sludge. All concentrations of phenol and low concentrations (20 mg/L) of 2-chlorophenol, 2-nitrophenol, 4-nitrophenol and 2,4-dinitrophenol were completely mineralized. Higher concentrations of these same substrates (100 mg/L) and all concentrations of dimethylphenol, 3-methyl-4-chlorophenol and 2-methyl-4,6-dinitrophenol were observed to undergo no significant mineralization of added substrate and inhibited methanogenesis to varying degrees. Significant biotransformation of the monosubstituted nitrophenols occurred, resulting in the production of the corresponding aminophenols. Acclimation for most compounds took several days to weeks before methane could be detected in the substrate-amended cultures. Generally, the greater the substitution of the phenolic ring, the greater were the recalcitrance and toxicity of the substrate. The fate of these compounds can be significantly influenced by both their concentration and their residence time in anoxic environments.
Thermal modulation of benzo[a]pyrene uptake in the gulf toadfish, Opsanus beta
Authors: Kennedy Christopher J. , Gill Kenneth A. , Walsh Patrick J. 
Published: March 2010

Abstract
Gulf toadfish, Opsanus beta, were exposed to initial [14C]benzo[a]pyrene (BaP) concentrations of 5μg/L in a simple static system at high and low temperatures (18 or 28°C) following long-term (&gt;4 weeks) acclimation to these temperatures or an acute temperature change (18 to 28°C or 28 to 18°C) to assess the effects of temperature on the uptake and disposition of BaP. BaP uptake was estimated from the disappearance of BaP from the water. Uptake rates estimated at initial BaP concentrations for the four temperature treatments (acclimation temperature: exposure temperature), 28:18, 28:28, 18:18 and 18:28°C, were 0.020 ± 0.001, 0.051 ± 0.005, 0.031 ± 0.004 and 0.065 ± 0.004 μg BaP/g body weight/h (±se, N = 6). The decrease in BaP uptake with decreasing BaP concentration indicates that BaP uptake is directly proportional to the concentration in water, and calculated Q10 values suggest that uptake is modulated by temperature-induced changes in respiration rate or convection volume. BaP was detected in all tissues examined, with the highest levels in the bile, the liver, the kidney and the gills. Greater uptake rates of carcinogens such as BaP at higher temperatures may in part explain higher rates of tumor formation in fish exposed to carcinogens at high temperatures.
Effects of freezing on toxicity of sediments contaminated with ddt and endrin
Authors: Schuytema Gerald S. , Nebeker Alan V. , Griffis William L. , Miller Clifford E. 
Published: March 2010

Abstract
Two freshwater sediments containing 3 and 11% total organic carbon (TOC) were spiked with DDT and endrin to compare the effects of cold (4°C) and frozen (−20°C) storage of the sediment on toxicity to the amphipod Hyalella azteca in 10-d tests. Toxicity of the DDT-spiked sediment was reduced when it was frozen for 14 d. LC50 values for cold-stored and frozen-stored sediments were 4.2 and 7.3 μg/g DDT (calculated on dry solids basis) at 3% sediment TOC and 11.1 and 23.2 μg/g DDT at 11% sediment TOC, respectively. Toxicity of the 3% TOC endrin-spiked sediment was reduced by freezing; it exhibited LC50s of 5.1 and 7.7 μg/g endrin, respectively, for cold and frozen storage. Toxicity of endrin in two tests in the 11% TOC sediment remained essentially unchanged by freezing. LC50s were 19.6 and 21.7 μg/g endrin for cold and frozen sediments in one test and 10.3 and 9.8 μg/g endrin in the second test. Decreased toxicity was assumed to be related to the release of soluble organic carbon from the sediments during freezing and thawing. Relative differences in toxicity between DDT and endrin for cold and frozen sediments appear to be related to the different adsorptions of the chemicals onto the released carbon.
Effects of kelthane® on reproduction of captive eastern screech-owls
Authors: Wiemeyer Stanley N. , Spann James W. , Bunck Christine M. , Krynitsky Alexander J. 
Published: March 2010

Abstract
Eastern screech-owls (Otus asio) were fed diets containing 10 ppm Kelthane® with 3.4% DDT-related contaminants (old technical formulation), 10 ppm Kelthane with no detectable DDT contaminants (new technical formulation) or a control diet. Food consumption, adult weight and date of initiation of egg laying were similar for birds in control and dosed treatment groups. Most measures of reproductive success were similar for control and dosed treatment groups. Shell weight and thickness index were significantly lower for both dosed groups than for controls. Shell thickness was significantly lower for the new Kelthane treatment than for controls. Concentrations of p,p'-DDE were significantly higher in eggs laid by pairs receiving old Kelthane than in those of birds receiving new Kelthane or in controls. Concentrations of dichlorobenzophenone, dicofol and dechlorodicofols were significantly higher in carcasses of dosed owls than in controls, whereas concentrations of DDE were significantly higher in carcasses of owls fed old Kelthane than in controls or owls fed new Kelthane.
Time-toxicity relationships in fish exposed to the organochlorine pesticide methoxychlor
Authors: Heming Thomas A. , Sharma Arvind , Kumar Yogesh 
Published: March 2010

Abstract
Time-toxicity relationships for methoxychlor were developed for five species and two stocks of fish (lake whitefish, Coregonus clupeaformis; spottail shiner, Notropis hudsonius; walleye, Stizostedion vitreum vitreum; white sucker, Catostomus commersoni; and two stocks of rainbow trout, Salmo gairdneri). Four different pulse regimes were tested, namely, a 2-h methoxychlor exposure followed by 94 h in fresh water, a 6-h exposure followed by 90 h in fresh water, a 24-h exposure followed by 72 h in fresh water, and a 96-h exposure. Time-toxicity relationships for methoxychlor varied inter- and intraspecifically. Intraspecies effects were probably size related; the 96-h median lethal concentration (LC50) for rainbow trout was 9.36 μg/L (95% C.L. 5.71, 15.3) for stock A fish (average size 1.2 g) and 31.2 μg/L (95% C.L. 24.7, 39.6) for stock B fish (average size 6.7 g). Methoxychlor exhibited a delayed toxic effect, the relative magnitude of which was a function of exposure duration and concentration, and fish species. Of the fish species examined, walleye was the most sensitive to short-term pulses (&lt;24 h) of methoxychlor. Walleye had a relatively low 96-h LC50 (19.2 μg/L; 95% C.L. 9.00, 41.1), experienced the greatest delayed toxic effects and, in terms of median survival time (tm), was most sensitive to changes in methoxychlor concentration. Rainbow trout appeared to be the species most sensitive to chronic methoxychlor exposure; its asymptotic LC50 (stock A 4.05 ± 2.84 μg/L, stock B 5.14 ± 3.14 μg/L) was significantly lower than those of other species. White sucker was the species least sensitive to acute exposure. White suckers experienced no delayed toxic effects and had the highest 96-h (114 μg/L; 95% C.L. 87.7, 150) and asymptotic LC50 (205 ± 85 μg/L) values.
Chronic effects of the photoenhanced toxicity of anthracene on Daphnia magna reproduction
Authors: Holst Linda L. , Giesy John P. 
Published: March 2010

Abstract
The chronic effects of exposure to anthracene and ultraviolet radiation (UVR) on Daphnia magna reproduction were investigated. D. magna were exposed to anthracene in the presence or absence of ecologically relevant intensities of UVR for 21 d. Exposure to 8.2 μg/L anthracene in the absence of UVR significantly reduced the number of neonates produced by 13.8%; however, exposure to UVR in the absence of anthracene had no significant effect on the fecundity of D. magna. Concurrent exposure of D. magna to UVR and anthracene resulted in further reduced survival and fecundity. Exposure of D. magna to 7.2 μg/L anthracene and 117 μW/cm2 UV-A radiation resulted in 70% mortality or a 69% decrease in production of neonates by D. magna that survived. The reduction in fecundity was proportional to both anthracene concentration and UVR intensity. Equations were developed that predict the relative percent reduction in production of neonates due to the photoenhanced toxicity of anthracene given a particular anthracene concentration and UVR intensity.
Dynamics of organochlorine compounds in herring gulls: III. Tissue distribution and bioaccumulation in lake ontario gulls
Authors: Braune Birgit M. , Norstrom Ross J. 
Published: March 2010

AbstractApparent biomagnification factors (BMFs, wet weight basis) for organochlorine compounds in herring gulls (Larus argentatus) in Lake Ontario were shown to be related to chlorine substitution patterns in the case of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PCBs accumulated according to the availability of adjacent positions not substituted with chlorine: (a) para-meta unsubstituted (P group), mean BMF 20 ± 6.2; (b) meta-ortho unsubstituted (M group), mean BMF 87 ± 36; and (c) no adjacent unsubstituted positions (blocked, B group), mean BMF 154 ± 39. Among the other organochlorines, DDT, cis- and trans-nonachlor, dieldrin and octachlorostyrene magnified to the least extent (BMF 3-19), and photomirex, mirex and DDE magnified to the greatest extent (BMF 85-100). Of the PCDDs and PCDFs, 2,3,7,8-TCDD and 2,3,4,7,8-PnCDF biomagnified to a greater degree than did other congeners (BMF 32 and 7, respectively). There were no significant differences among egg-to-whole-body ratios (mean 0.60 ± 0.11, lipid weight basis) for any of the organochlorines except PCDDs and PCDFs, indicating that partitioning among lipid pools in the body is the main determining factor in tissue distribution. Egg-to-whole-body ratios for PCDDs (mean 1.2 ± 0.33) and PCDFs (mean 0.87 ± 0.02) were higher than but not significantly different from those for other organochlorines. Liver-to-whole-body ratios (mean 0.80 ± 0.16) also did not differ significantly among organochlorines, except that heptachlor epoxide, dieldrin, PCDDs and PCDFs had higher ratios. The mean fraction of the total body burden of PCDDs and PCDFs contained in the liver ranged from 5 to 55%, compared with 1 to 5% among the other organochlorines, and it increased with degree of chlorination.
Findings of tributyltin, dibutyltin and monobutyltin in bivalves from selected U.S. coastal waters
Authors: Uhler Allen D. , Coogan Theodore H. , Davis Kenneth S. , Durell Gregory S. , Steinhauer William G. , Freitas Sandra Y. , Boehm Paul D. 
Published: March 2010

Abstract
A method is presented for determining trace levels of tributyltin (TBT) and its degradation products dibutyltin (DBT) and monobutyltin (MBT) and the TBT manufacturing impurity tetrabutyltin (TTBT) in bivalve mollusc tissue. Butyltin compounds were analyzed in bivalve molluscs collected from selected near-shore sites of the U.S. east and west coasts. All bivalves from the sites investigated were contaminated with TBT, DBT and, sporadically, MBT. The ratio of TBT/DBT in sentinel organism tissue appears to be a species-specific equilibrium value, with average values for Mytilus edulis of 2.5 and Mytilus californianus of 11.6.
Polychlorinated dibenzofurans and polychlorinated dibenzo-p-dioxins in great lakes fish: A baseline and interlake comparison
Authors: De Vault David , Dunn William , Bergqvist Per-Anders , Wiberg Karin , Rappe Christoffer 
Published: March 2010

Abstract
Fish from each of the Great Lakes and Lake St. Clair were analyzed for 10 congeners of polychlorinated dibenzofurans (PCDFs) and 8 congeners of polychlorinated dibenzo-p-dioxins (PCDDs). PCDFs and PCDDs were identified above detection limits in samples from each lake. Concentrations of PCDFs, principally 2,3,7,8-TCDF, were highest (102.4 ng/kg) in Lake Michigan lake trout and lowest in late trout from Lake Superior (20.9 ng/kg). Total PCDD concentrations ranged from 7.2 ng/kg in Lake Superior lake trout in 64.5 ng/kg in Lake Ontario lake trout. Concentrations of 2,3,7,8-TCDD ranged from 1.0 ng/kg in Lake Superior lake trout to 48.9 ng/kg in lake trout from Lake Ontario.
While the upper lakes were somewhat similar in the absolute concentration and composition of PCDFs and PCDDs, principle components analysis identified statistically significant inter- and in-tralake differences in the composition of total PCDF and total PCDD. These differences suggest differences in the sources of these compounds to each of the Great Lakes.