bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecotoxicological relevance of atrazine in aquatic systems
Authors: Huber Wilfried
Published: March 2010

In this report an attempt is made to outline the ecotoxicological role of atrazine in aquatic ecosystems. A brief discussion of the chemistry and metabolism of atrazine is followed by a discussion of the occurrence of this herbicide in the environment. Peak levels for occurrence of atrazine in surface water range from up to 90 μg/L for flowing water to 2 μg/L for standing water. In reality, most values are significantly lower. As with ground water, in which atrazine has also been detected, great caution must be taken when interpreting data on the presence of atrazine in the environment. Atrazine is taken up by nearly all members of the aquatic biocenoses, but in many cases it is also quickly eliminated. The importance of these processes is discussed. The ecotoxicological effects of atrazine on producers, consumers, and decomposers as well as on ecosystem functions first become observable at levels of 20 μg/L or more; the changes are not lasting, even when studied over long periods. Indirect effects are also taken into account in the definition of the threshold value. Deviations from the ecotoxicological threshold value indicated by higher or lower toxi-cological threshold values in the case of individual organisms are also evaluated. Furthermore, the threshold value is compared with the environmental concern level (EEC) of atrazine. The final assessment is that although atrazine may be potentially hazardous to the environment, the level of hazard depends on the concentration and degree of exposure. It can be assumed that at concentrations of up to 20 μg/L, atrazine does not cause any permanent damage to aquatic ecosystems.
Lethal and sublethal effects of the sediment-associated PCB aroclor 1254 on a meiobenthic copepod
Authors: Dipinto Lisa M. , Coull Bruce C. , Chandler G. Thomas
Published: March 2010

Acute toxicity tests were performed on field-collected copepods (Microarthridion littorale) using the sediment-associated polychlorinated biphenyl (PCB) Aroclor 1254 (i.e., PCB concentrations in bulk sediments in the bound and/or unbound states). Three replicates of 50 adult copepods (25 males + 25 females) were exposed to five levels of PCB-contaminated sediments for 96 h and compared to untreated controls and solvent controls. LC50 concentrations were nearly twice as high for females (251 mg/kg) as for males (117 mg/kg). To determine the effects of the PCB on reproductive output of the copepods, copulating pairs of Microarthridion littorale were allowed to reproduce in concentrations of Aroclor 1254-contaminated sediments below LC50 values. Two experimental trials with 10 and 15 replicates, each with one pair of Microarthridion littorale in copu-lus, were conducted for 12 d, the normal time needed for females to produce one set of nauplii and carry a second clutch of eggs. In both experiments, a significant decrease in number of nauplii was found with Aroclor contamination. Although NOECs were not determined, high concentrations (83 mg/kg) of the sediment-associated Aroclor 1254 were required to affect mortality significantly, whereas lower levels (4 mg/kg) impaired reproduction.
Toxicological evaluation of the effects of waste-to-energy ash-concrete on two marine species
Authors: Hamilton Kirk L. , Nelson Walter G. , Curley Jeri L.
Published: March 2010

The toxicological effects of waste-to-energy ash-concrete on survivorship, growth, and fecundity (end-point parameters) of Mysidopsis bahia and on survivorship and growth of Menidia beryllina were evaluated with the 7-d static-renewal toxicity test. Leachate (10-, 5-, and 1-d) and elutriate (100, 50, 25, 12.5, and 6.25%) solutions were prepared from experimental ash-concrete test cylinders constructed from concrete with additions of either bottom ash (mix BA), mixed bottom ash and scrubber residue (70:30%; mix BA:SR), or mixed bottom ash and fly ash (60:40%, mix BA:FA). Control experiments with concrete (without ash) and pH (7-9.5) were conducted to assess any toxic effects of the stabilization process. pH did not affect end-point parameters of Mysidopsis bahia or Menidia beryllina. However, the 100% elutriate solution made from concrete reduced survivorship of Mysidopsis bahia. For experiments with ash-concrete test cylinders with the BA mixture, 10-d leachate solution reduced survivorship of Mysidopsis bahia and the 100% elutriate solutions reduced survivorship of Mysidopsis bahia and Menidia beryllina. With the BA:SR mixture, the 100 and 50% elutriate solutions reduced survivorship of Mysidopsis bahia, and the 10-d leachate solution reduced survivorship of Menidia beryllina. The BA:FA 10- and 5-d leachate solutions and the 100, 50, and 25% elutriate solutions reduced survivorship of Mysidopsis bahia.
Municipal sludge metal contamination of old-field ecosystems: Do liming and tilling affect remediation?
Authors: Benninger-Truax Mary , Taylor Douglas H.
Published: March 2010

Mechanisms of ecosystem recovery following 11 years of sewage sludge disposal were addressed by examining the effects of tilling and/or liming on soil chemistry and the heavy metal (Cd, Cu, Pb, and Zn) concentrations in soil, earthworms, vegetation, spiders, and crickets. In 1989 and 1990, subplots in each of three former 0.1-ha, long-term treatments (sludge, fertilizer, and control) were either unmanipulated or manipulated via tilling and/or liming. Liming significantly increased the pH of soil from the long-term sludge and fertilizer plots, and the combination of tilling and liming affected the heavy metal concentrations in earthworms, as lower concentrations of Cd, Cu, Pb, and Zn were found in earthworms collected from subplots that had been both tilled and limed. However, most observed significant differences in heavy metal concentrations reflected the long-term treatments, as heavy metal concentrations tended to be greater in the soil and biota collected from sludge-treated plots. Thus, heavy metals remained in the soil in forms available to the biota, regardless of the cessation of sludge application or subplot manipulations (liming and/or tilling) for two years following cessation of sludge application.
Predicting and measuring drift of Bacillus thuringiensis sprays
Authors: Barry John W. , Skyler Patricia J. , Teske Milton E. , Rafferty James A. , Grim Bruce S.
Published: March 2010

Drift of the pesticide Bacillus thuringiensis Berliner var. kurstaki (Bt) was measured downwind from a gypsy moth (Lymantria dispar L.) treatment block in mountain terrain. The study was conducted in conjunction with a project to eradicate the moth along the Wasatch mountain range of Utah. Objectives of the study were to quantitate drift, to evaluate drift sampling methods, and to compare FSCBG (Forest Service Cramer-Barry-Grim) computer model predictions to field measurements of Bt based on colony-forming units. The treatment block was sprayed by helicopter three times, within a 12-d period during June 1991, which provided a study of three replicates. During each spray, downslope drainage winds carried the spray over an array of samplers that extended 3,150 m downwind. The FSCBG dispersion model, exercised after the treatments, used meteorological inputs measured during the treatments to predict spray deposition and airborne dosage of Bt. Results of the study demonstrated a correlation among dosage, deposition and total flux samplers; a potential of Bt drift of at least 3,150 m; and FSCBG model predictions that generally followed the field recovery data.
Distribution of PCB congeners in seven lake systems: Interactions between sediment and food-web transport
Authors: Macdonald Colin R. , Metcalfe Chris D. , Balch Gordon C. , Metcalfe Tracy L.
Published: March 2010

A study was conducted to examine the role of two processes, partitioning of PCBs between sediment and biota and food-web transport, in determining the concentration of PCB congeners in the biota of seven lakes. Biota PCB concentration (lipid)-to-sediment PCB concentration (organic carbon), or BSF, ratios were calculated as markers of the partitioning of PCBs between biota and sediment, and biota PCB concentration (lipid)-to-zooplankton PCB concentration (lipid), or BAF, ratios were calculated as markers of the transport of PCBs through food webs. The lakes ranged from a shallow, well-mixed lake with a historic input of Aroclor technical mixtures to deeper, oligotrophic systems in which atmospheric deposition was the only known source. BSF ratios ranged from approximately one in cyprinids and zooplankton in all lakes to 30 in yellow perch in one lake. A significant correlation between lake maximum depth and the combined BSF ratios for all biota indicated that PCBs were generally more available for accumulation in the shallower lakes, regardless of the PCB source. Principal component analysis (PCA) showed that the biota in the shallower lakes had higher ratios of higher chlorinated congeners, suggesting that predictions of equal concentrations of hydrophobic contaminants on a lipid basis in sediment and lower trophic levels may significantly underestimate the accumulation of very hydrophobic compounds in the organisms of some lake systems. BAF ratios ranged from approximately one in the lower trophic levels to approximately 10 in lake trout. A significant relationship between the BAF ratio and lake maximum depth for combined data for all biota, and particularly for smallmouth bass (Micropterus dolomieui Lacé-pède), probably indicated the increasing role of food-web transport of PCBs in deeper lakes. PC analysis of BAF ratios for individual congeners characterized lake trout (Salvelinus namaycush Wal-baum) and yellow perch (Perca flavescens) on the basis of higher ratios for the majority of congeners but also split the two species on the basis of higher ratios of lower chlorinated congeners in perch and highly chlorinated congeners in lake trout. The separation of the two species collected from the same lakes was attributed to their position in the food web.
The oxidative dechlorination reaction of 2,4,6-trichlorophenol in dilute aqueous suspensions of manganese oxides
Authors: Ukrainczyk Ljerka , McBride Murray B.
Published: March 2010

Oxidation of 2,4,6-trichlorophenol (TCP) by layered manganese oxides (Na and Co-buserite) in dilute acidified aqueous suspension gives 2,6-dichloro-p-benzoquinone as a major product. This compound is likely to further polymerize and become incorporated into humuslike materials. The oxidation rate was higher at lower pH and higher on Na-buserite compared to Co-buserite. TCP reacted at a faster rate than unsubstituted phenol at pH 3 and 5.5, which is explained by (a) the lower half-wave potential of TCP compared to phenol; (b) a stronger bond dipole associated with the electronegative halogen, favoring an addition step in nucleophilic substitution; and (c) easier deprona-tion of TCP at the manganese oxide-water interface due to its lower pKa. IR spectroscopy shows that TCP adsorbs in deprotonated form on the surface of manganese oxide, and it cannot be washed from the surface by water. Nucleophilic attack by addition-elimination is suggested as a mechanism of TCP dechlorination and oxidation.
Oxidation and dechlorination of chlorophenols in dilute aqueous suspensions of manganese oxides: Reaction products
Authors: Ukrainczyk Ljerka , McBride Murray B.
Published: March 2010

Some monomeric and dimeric oxidation products of para- and/or ortho-chlorinated phenols in dilute (1 mmol/L phenol), acidified, aqueous suspensions of manganese oxide (Na-buserite) were identified by MS, Fourier-transform IR spectroscopy and UV/visible spectroscopy. The para-chlorinated phenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, 4-chloro-2-methylphenol) gave corresponding p-benzoquinones (benzoquinone, 2-chlorobenzoquinone, 2,6-dichlorobenzoquinone, 2-methylbenzoquinone) as the detectable water-soluble oxidation products. Dimeric products were present in the extracts obtained by washing the oxide with methylene chloride. Michael addition of phenolate to quinone seems to be the predominant mode of coupling. Chlorinated phenols without chlorine in the para-position (2-chlorophenol, 2,6-dichlorophenol) were more difficult to oxidize and afforded diphenoquinones as the only detectable water-soluble products. For all studied phenols, with the exception of 2,4,6-trichlorophenol, the amount of water-soluble products accounts only for a small fraction of oxidized phenol. The quinone and diphenoquinone products readily couple with phenols into humuslike materials.
The effect of cosolutes on the aqueous solubilities and octanol/water partition coefficients of selected polychlorinated biphenyl congeners
Authors: Li An , Doucette William J.
Published: March 2010

Aqueous solubilities (S) and 1-octanol/water partition coefficients (Kow) of four PCBs—4-chlorobiphenyl, 2,4,6-trichlorobiphenyl, 2,3,4,5-tetrachlorobiphenyl, and 2,2′,4,4′,6,6′-hexachlo-robiphenyl—were determined both individually and in pairs, using a generator-column technique, to investigate the effect of cosolutes on S and Kow, No statistical differences between S and Kow measured individually and in pairs were observed for the four PCBs in 20 out of 24 cases. In the other four cases S or Kow measured in the presence of a cosolute was only slightly different from that observed individually.
Chemical, physiological and morphological studies of feral baltic salmon (Salmo salar) suffering from abnormal fry mortality
Authors: Norrgren L. , Andersson T. , Bergqvist P.-A. , Björklund I.
Published: March 2010

In 1974, abnormally high mortality was recorded among yolk-sac fry of Baltic salmon (Salmo salar) originating from feral females manually stripped and fertilized with milt from feral males. The cause of this mortality, designated M74, is unknown. Our hypothesis is that xenobiotic compounds responsible for reproduction failure in higher vertebrates in the Baltic Sea also interfere with reproduction in Baltic salmon. The significance of M74 should not be underestimated, because the syndrome has caused up to 75% yearly mortality of developing Baltic salmon yolk-sac larvae in a fish hatchery dedicated to production of smolt during the last two decades. We cannot exclude the possibility that only a relatively low number of naturally spawned eggs develop normally because of M74. No individual pollutant has been shown to be responsible for the development of M74 syndrome. However, a higher total body burden of organochlorine substances may be responsible for the M74 syndrome. The presence of induced hepatic cytochrome P450 enzymes in both yolk-sac fry suffering from M74 and adult feral females producing offspring affected by M74 supports this hypothesis. In addition, the P450 enzyme activity in offspring from feral fish is higher than the activity in yolk-sac fry from hatchery-raised fish, suggesting that feral Baltic salmon are influenced by organic xenobiotics.
Induction of mfo enzymes and production of bile metabolites in rainbow trout (Oncorhynchus mykiss) exposed to waste crankcase oil
Authors: Upshall C. , Payne J.F. , Hellou J.
Published: March 2010

It is difficult to assess the toxicological significance of complex mixtures of contaminants in the environment because of paucity of dose-response studies. Rainbow trout (Oncorhynchus mykiss) were exposed per os to waste crankcase oil and analyzed for hydrocarbon classes, 26 polycyclic aromatic compounds (PACs) and 66 elements. MFO enzyme activity, measured as 7-ethoxyresorufin O-deethylase (EROD) was induced in liver, kidney, and heart. The threshold level for induction in liver was approximately 3 mg of PACs (sum of 26 PACs) per kilogram fish. A dose-response relationship was obtained for liver and kidney but not for the heart. In a time-response study, liver, kidney, and heart MFO activity increased (14-, 5-, and 3-fold, respectively), reaching a maximum between days 1 and 4, then decreased to basal levels by day 12. Analysis of bile metabolites, as gluc-uronide and sulfate conjugates, showed a pattern similar to that displayed by MFO induction, possibly with a slight delay. This study establishes time- and dose-response relationships for MFO enzyme induction and appearance of bile metabolites in fish exposed to an environmentally important source of PACs.
Survival and pesticide exposure of northern bobwhites (Colinus virginianus) and eastern cottontails (sylvilagus floridanus) on agricultural fields treated with counter® 15G
Authors: Tank Susan L. , Brewer Larry W. , Hooper Michael J. , Cobb George P. , Kendall Ronald J.
Published: March 2010

During 1988 and 1989 northern bobwhites (Colinus virginianus) and eastern cottontails (Sylvilagus flondanus) were radiotagged and their daily survival monitored on six study sites treated with the organophosphorus insecticide-nematicide Counter®15G (terbufos), at the rate of 1.45 kg a.i. per hectare, and on three reference sites. Nonlethal blood samples were collected at the time of capture and during subsequent recaptures to determine exposure to terbufos through blood ChE analysis. Survival rates of radiotagged eastern cottontails and blood plasma ChE activities were not different between treated and reference sites in either year. Gastrointestinal (GI) tracts of two cottontail carcasses found in 1988 contained traces of terbufos in concentrations <0.046 ppm. No terbufos was detected in GI tracts in 1989. There were no differences in survival rates of radiotagged northern bobwhites among treatments. Mean blood plasma ChE activities of northern bobwhites were significantly lower (P < 0.05) on treated sites than on reference sites both years, including sublethal exposure to the test chemical. No GI tract residues were detected in bobwhites in 1988, and GI tract residues were detected in trace amounts (<0.046 ppm) in only one bobwhite carcass in 1989.
Validation of some extrapolation methods used for effect assessment
Authors: Emans H.J.B. , Plassche E.J.V.D. , Canton J.H. , Okkerman P.C. , Sparenburg P.M.
Published: March 2010

For effect assessment several extrapolation methods can be used to derive the concentration of toxic chemicals above which adverse effects on aquatic ecosystems may occur. These methods are based on single-species toxicity data. At present, however, it is uncertain whether the values calculated with these extrapolation methods really represent accurate estimations of concentrations harmless to ecosystems. Therefore a validation of extrapolation methods was carried out by comparing NOECs derived from multiple-species (semi-) field experiments with extrapolated values. In this study validation was restricted to the methods of Aldenberg and Slob and Wagner and Løkke and a modification of the method of the U.S. Environmental Protection Agency. Multiple-species experiments for organic compounds and metals in aquatic ecosystems were studied. For only 29 compounds, 19 organic compounds, and 10 metals, one or more multiple-species NOECs could be derived. For 11 of these compounds an insufficient amount of single-species toxicity data was available to apply the methods of Aldenberg and Slob and Wagner and Løkke. With reservations, due to this paucity of data, it is concluded that single-species toxicity data can be used to derive “safe” values for the aquatic ecosystem. Furthermore, extrapolation methods seem to be a good basis for determining these values. Based on the results of this study, the best correlation between multiple-species NOECs and extrapolated values can be obtained with the methods of Aldenberg and Slob and Wagner and Løkke, both with a 95% protection level and a 50% confidence level.
Salt-marsh processes: A Review
Authors: Vernberg F. John
Published: March 2010

Salt marshes are found between the high tide and the near-shore sublittoral zones along the coasts and up estuaries of continents, primarily in the temperate zone. They flourish in regions where much silt is carried to the coastal regions by rivers or where geological processes favor erosion and suspension of silt. Salt marshes have multiple ecological and economic values. They have a high rate of primary productivity; provide habitats for many marine species (including commercially important organisms); assist in flood and erosion control; lessen the effects of stormwater surges; and improve water quality by filtering pollutants, excess nutrients, and disease-causing microorganisms. In addition, this habitat is used for recreational and educational purposes by millions of people who spend millions of dollars. Although the myriad functions and uses of this habitat attest to its tremendous importance, legal protection of salt marshes varies significantly throughout the world. Salt-marsh processes are governed by the interactions between “natural” physical, chemical, geological, and biological factors. Of importance to ecotoxicologists and other scientists is understanding the intimate interaction between these various abiotic and biotic factors. This paper reviews the functional processes of salt marshes and discusses recent research advances under the following major headings: (a) physical, geological, and chemical factors; (b) biotic factors (including productivity of vascular plants, phytoplankton, epibenthic algae, and attached macrophytes; secondary production of primary and secondary consumers; and decomposition; (c) material cycling, biogeo-chemical cycling, and nutrients; (d) long-term changes; and (e) interaction with adjacent ecosystems.
Ecotoxicology and wetland ecosystems: Current understanding and future needs
Authors: Catallo W. James
Published: March 2010

The term wetlands refers to a mosaic of important ecosystems that typically form transition zones between uplands and aquatic environments. These areas provide support functions for natural and living resources and mediate biogeochemical transformations of global significance. It is becoming clear that the introduction of toxic and other contaminants to large wetland areas has contributed to a series of undesirable trends in habitat quality; availability of valuable fish and wildlife; and quality of associated resources, including surface and ground waters. The purpose of this review is to indicate the importance of wetlands to regional and global ecology and discusses research on the effects of contaminants in wetland ecosystems. Areas of needed future research also are suggested.
Modeling mobility and effects of contaminants in wetlands
Authors: Dixon Kenneth R. , Florian James D.
Published: March 2010

Early efforts at modeling wetland ecosystems were aimed primarily at reflecting biomass or nutrient dynamics. A number of models have been developed for different wetland types, including coastal salt marshes, mangrove wetlands, freshwater marshes, swamps, and riparian wetlands. The early ecosystem models were mostly simple compartment models with linear, constant-coefficient differential equations used to simulate biomass or nutrient dynamics. Practically no contaminant flux was incorporated into these models. With few exceptions, the ecosystems were considered spatially homogeneous. At the same time that the ecosystem models were being developed, considerable effort was given to modeling various wetland processes, such as circulation and sediment transport. Other process-level modeling included plant and animal uptake and elimination of both organic chemicals and heavy metals. The level of detail in these process models, however, has not been applied to most ecosystem models. There has been a recent trend, however, to increase the complexity of ecosystem-level models and to incorporate spatial dynamics. These developments should greatly enhance the ability to simulate contaminant transport and effects in wetlands.
Detection of contaminated samples using a two-way compositing scheme
Authors: Skalski John R. , Word Jack Q.
Published: March 2010

Compositing of sediment or water samples provides an opportunity to screen numerous samples economically if contamination is a relatively rare occurrence. However, standard compositing procedures simply identify that contamination exists among one or more constituent samples of the composite. Using a two-way compositing strategy, detected contamination in composited samples can be attributed directly to constituent samples without further analyses. Procedure is illustrated using benthic sediment samples contaminated with crude oil following an oil spill. The proposed compositing scheme has a relative efficiency of n/2 compared to the analysis of individual samples when n2 is the number of samples screened (e.g., n2 = 16 samples, relative efficiency is 4/2 = 2).
Biological and chemical mineralization of pyridine
Authors: Ronen Zeev , Horvath-Gordon Maria , Bollag Jean-Marc
Published: March 2010

A comparison was made between biological and chemical mineralization of pyridine, an N-heterocyclic pollutant, in a liquid culture and a slurry of ground water and subsurface sediment. A bacterial culture of an Alcaligenes sp. that degrades pyridine was found to be more effective at oxidizing [2,6-14C]pyridine to 14CO2 than Fenton's reagent. Alcaligenes sp. converted 73.1% of the 14C-labeled pyridine to 14CO2, whereas the Fenton reagent converted 65.6% of the compound. In the case of bacteria, the remaining chemical was incorporated primarily into biomass (9.2%), whereas the remaining pyridine was converted to unidentified products (16.3%) by the Fenton reagent. However, based on chromatographic analysis, these compounds were not mono-hydroxylated pyridines. Mineralization of pyridine by Fenton's reagent was affected by the concentration of H2O2 and by the concentration and oxidation state of available iron. Maximal mineralization occurred at a concentration of more than 0.15% H2O2 (44 mM), 1 mM Fe3+, or 2 mM Fe2+. Furthermore, the rates of both microbial and chemical mineralization were influenced by the initial pyridine concentration. Maximum specific rates of mineralization were 6.5 μg/h/mg biomass for the bacteria and 2.7 μg/h/mg Fe2+ for the Fenton reagent. The feasibility of using Fenton's reagent for treating ground water and subsurface sediments polluted with pyridine was found to be limited, because only 24.5% of the pyridine was converted to CO2. In contrast, when cultures of the Alcaligenes sp. were used to treat ground water, as much as 54.4% of the labeled compound was mineralized to 14CO2.
Photoeffects of textile dye wastewaters: Sensitization of singlet oxygen formation, oxidation of phenols and toxicity to bacteria
Authors: Tratnyek Paul G. , Elovitz Michael S. , Colverson Peter
Published: March 2010

An effluent sample from a municipal wastewater treatment plant that receives a heavy loading from two textile dyeing facilities was tested for a variety of photoeffects. Solar irradiation of solutions containing the effluent produced evidence for sensitized formation of transient oxidants, primarily singlet oxygen; dye-sensitized photooxidation of several phenols; and photoinhibition of Escherichia coli.
MFO activity in carp (Cyprinus carpio) exposed to treated pulp and paper mill effluent in lake coleman, Victoria, Australia, in relation to AOX, EOX, and muscle PCDD/PCDF
Authors: Ahokas J.T. , Holdway D.A. , Brennan S.E. , Goudey R.W. , Bibrowska H.B.
Published: March 2010

European carp (Cyprinus carpio) exposed to highly treated pulp mill effluent in Lake Coleman, a shallow-water lake in southern Victoria, Australia, had significantly elevated hepatic microsomal EROD levels relative to reference fish from a nearby unexposed water body (Dowds and Heart morasses). Mean hepatic microsomal EROD activity appeared to be correlated with site adsorbable organic halogen (AOX) levels, with a simple linear regression yielding the equation Y = 0.059X+ 1.415 (r2 = 0.93, n = 5), where Y is mean EROD activity in nanomoles per minute per milligram and X is mean AOX concentration in micrograms per liter. Mean liver EROD activity was poorly related with fish muscle-tissue extractable organic halogen (EOX) and sediment EOX concentrations. Hepatic microsomal EROD activity also appeared to be correlated with the low levels of PCDD/PCDFs measured in carp muscle (1.0-4.0 ppt TCDD international toxic equivalents (TEs) in effluent-exposed fish muscle compared to 0.48-0.64 ppt TEs in reference fish muscle). Simple linear regression of mean EROD activity in carp liver with the mean fish muscle dioxin content yielded the equation Y= 6.514X+ 5.754 (n = 4, r2 = 0.88), where Y is mean EROD activity in nanomoles per minute per milligram and X is mean dioxin concentration in ppt of TCDD TEs. Hepatic microsomal ECOD activity, however, was not significantly different at any exposure site from the reference sites. Overall, Lake Coleman contained between 4.5 and 9.3 times the water AOX levels, 0.8 and 13.7 times the sediment EOX levels, 1.5 and 2.2 times the carp muscle-fat EOX levels, 5.0 and 5.3 times the carp whole-muscle TCDD toxic equivalents, and 6.5 times the carp fat TCDD toxic equivalents, compared to the Dowds and Heart morass reference samples. Within Lake Coleman, mean liver microsomal EROD activity levels were 2.3 to 6.3 times higher than the Dowds and Heart reference sites, respectively. Tissue concentrations of PCDD/PCDF and water AOX levels reduced with increasing distance from the effluent point source. Carp liver microsomal EROD represented a good biomarker of exposure to low levels of organochlorine contaminants from well-treated pulp mill effluent.
Effects of water temperature and pH on toxicity of terbufos, trichlorfon, 4-nitrophenol and 2,4-dinitrophenol to the amphipod Gammarus pseudolimnaeus and rainbow trout (Oncorhynchus mykiss)
Authors: Howe George E. , Marking Leif L. , Bills Terry D. , Rach Jeffery J. , Mayer Foster L.
Published: March 2010

Acute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17°C), pH (6 5, 7 5, 8 5, 9 5), and time on the toxicity of terbufos, trichlorfon, 4 nitrophenol, and 2,4-dinitrophenol to rainbow trout (Oncorhynchus mykiss) and the amphipod Gammarus pseudohmnaeus, and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout and Gammarus exposed to terbufos, 4 nitrophenol, and 2,4 dinitrophenol The toxicity of all four chemicals was significantly affected by pH in all tests, except for Gammarus exposed to terbufos The toxicity of terbufos to rainbow trout and Gammarus was less at pH 7 5 than at higher or lower pH The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH The effect of pH on trichlorfon toxicity decreased with temperature Temperature significantly affected the toxicity of all four chemicals to both species Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols, toxicity decreased as temperature increased for rainbow trout Chemical bioconcentration was also significantly af fected by temperature and pH and was directly related to toxicity in most tests Significant interactive effects between toxicity modifying factors were also frequently observed Temperature and pH effects on chemical toxicity need to be consid ered in chemical hazard assessment to ensure adequate protection of aquatic organisms
Toxicity of carbaryl and malathion to two federally endangered fishes, as estimated by regression and Anova
Authors: Beyers Daniel W. , Carlson Clarence A. , Keefe Thomas J.
Published: March 2010

Toxicity of technical carbaryl, Sevin®-4-Oil, and technical malathion to federally endangered Colorado squawfish (Ptychocheilus lucius) and bonytail (Gila elegans) was estimated by 4-d renewal-acute and 32-d early life-stage (ELS) tests. Median lethal concentrations were estimated by probit analysis. Effect concentrations for ELS tests were estimated by ANOVA and an alternative procedure using a linear-plateau regression model. Linear-plateau regression estimated a threshold concentration above which toxic effects began to occur. Median lethal concentrations and 95% confidence limits (in parentheses) for carbaryl, Sevin-4-Oil, and malathion were 1.31 (1.23, 1.40), 3.18 (2.87, 3.52), and 9.14 mg/L (8.36, 10.0) for Colorado squawfish and 2.02 (1.78, 2.25), 3.31 (3.06, 3.55), and 15.3 mg/L (14.4, 16.4) for bonytail. NOECs for Colorado squawfish were 445 μg/L carbaryl and 1,680 μg/L malathion. The NOECs for bonytail were 650 μg/L carbaryl and 990 μg/L malathion. Threshold concentrations for Colorado squawfish in ELS tests were 364 μg/L carbaryl and 455 μg/L malathion. Threshold concentrations for bonytail were 217 μg/L carbaryl and 521 μg/L malathion. Estimates of effect concentrations from linear-plateau regression were consistently lower than those estimated by hypothesis testing. Linear-plateau regression models accounted for a significant amount of total variation and adequately described the observed concentration-response relation.
PCB and DDE methyl sulfones in mammals from Canada and Sweden
Authors: Bergman Åke , Kuroki Hiroaki , Norstrom Ross J. , Haraguchi Koichi , Béland Pierre
Published: March 2010

Levels of PCB methyl sulfones (MeSO2-CBs) and DDE methyl sulfones (MeSO2-DDEs) have been determined in tissues from polar bear (Ursus martimus), beluga whale (Delphinapterus leucas), and false killer whale (Pseudorca crassidens) from the Canadian environment, and grey seal (Halichoerus grypus), otter (Lutra lutra), and wild mink (Mustela vison) from the Swedish environment. Up to 30 MeSO2-CB congeners and three MeSO2-DDE isomers were shown to be present in the analyzed tissues. The concentration of total MeSO2-CBs ranged from 0.1 to 21 μg/g extracted lipids. 3-MeSO2-2,5,2′,4′,5′-penta-CB is the dominating MeSO2-CB congener in all the analyzed samples, but the corresponding 4-MeSO2-CB also is present in high concentrations. A smaller number of MeSO2-CBs, always dominated by the meta-substituted MeSO2-CBs, were present in livers of grey seal, otter, and mink than in adipose tissue or muscle. In all studied mammals the concentrations of MeSO2-CBs were higher in liver than in blubber or muscle. Seven PCB congeners were identified as precursors of the PCB methyl sulfones: 2,4,2′,5′-tetra-CB (CB-49), 2,5,3′,4′-tetra-CB (CB-70), 2,4,5,2′,5′-penta-CB (CB-101), 2,3,4,5,2′,5′-penta-CB (CB-87), 2,3,6,2′,4′,5′-hexa-CB (CB-149), 2,3,4,2′,3′,6′-hexa-CB (CB-132), and 2,3,4,2′,5′-hexa-CB (CB-141). All species except beluga whale contained 3-MeSO2-4,4′-DDE, but at a much lower concentration in mink and otter than in the other mammals. Polar bear and grey seal liver also contained 2-MeSO2-4,4′-DDE. The concentrations of 2- and 3-MeSO2-DDE ranged from 0.01 to 1.3 μg/g extracted lipids. A hitherto unknown MeSO2-DDE isomer was determined in false killer whale blubber by GC-MS, along with 2- and 3-MeSO2-4,4′-DDE and several unknown MeSO2-penta-CBs and MeSO2-hexa-CBs. tris(4-chlorophenyl)methanol was identified in the aryl methyl sulfone fraction of polar bear liver and grey seal blubber samples.
Chemical and biological 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in fly ash from combustion of bleached kraft pulp mill sludge
Authors: Kopponen Päivi , Törrönen Riitta , Välttilä Olli , Talka Esko , Tarhanen Juhani , Ruuskanen Juhani , Kärenlampi Sirpa
Published: March 2010

Fly ash was collected from five large-scale or pilot tests in which burning of bleached kraft pulp mill sludge was studied. The content of dioxin-like compounds in this fly ash was estimated both chemically and biologically. Fly ash was analyzed chemically for 17 PCDD and PCDF congeners by high-resolution GC-MS, and the data were transformed to Nordic TCDD equivalents. The biological analyses were based on the induction of several enzymes (aryl hydrocarbon hydroxylase [AHH], 7-ethoxyresorufin O-deethylase [EROD], aldehyde dehydrogenase-3 [ALDG3]) by the fly ash extracts in a mouse hepatoma cell line, Hepa-1. The inducing potencies were expressed as biological TCDD equivalents. There was a good correlation between the Nordic and the biological TCDD equivalents. Differences in the amounts of dioxin-like compounds among the combustions were attributed mainly to the boiler types and not to fuel characteristics or combustion parameters.
New quantitative approach for analysis of binary toxic mixtures
Authors: Haas Charles N. , Stirling Bruce A.
Published: March 2010

Humans generally are exposed simultaneously to a number of toxins, including complex mixtures of unknown and variable origin. Although procedures for assessing the potential toxic risks associated with exposure to individual chemicals are relatively well established, methods for assessing the risks of complex mixtures are still in the developmental stages. One source of considerable uncertainty in these estimates is the potential for interaction among chemicals in complex mixtures. The objective of this work was to gain a better understanding of the effects posed by toxicant interactions and to test a new approach for analyzing the dose-response effects of binary toxic mixtures. This new method of analysis enables a more rapid and quantitative assessment of the interactive effects of pairs of toxic chemicals. A number of experimental studies showing multicompo-nent toxicity were tested using the proposed approach. Both positive and negative interactions of the toxicants were documented for these studies, with significantly acceptable predictive capabilities observed for the model.
Chemical fate and transport in a domestic septic system: Sorption and transport of anionic and cationic surfactants
Authors: McAvoy D.C. , White C.E. , Moore B.L. , Rapaport R.A.
Published: March 2010

The sorption and transport of linear alkylbenzene sulfonate (LAS) and dialkyl quaternary ammonium compounds [ditallow dimethyl ammonium chloride (DTDMAC) and distearyl dimethyl ammonium chloride (DSDMAC)] were determined within the upper soil horizons and in the aquifer below a septic tank tile field at a study site in Ontario. Sorption of LAS was greatest immediately below the tile field (Kd = 17 L/kg) within the upper unsaturated soil horizons and lowest in the aquifer (Kd = 1 L/kg). LAS sorption appeared to be controlled by a hydrophobic mechanism and was positively correlated with the organic carbon (r = 0.9) and the clay content (r = 0.9) in the subsurface environment. The sorption of DTDMAC/DSDMAC (Kd = 25-62 L/kg) was an order of magnitude higher than LAS but showed no trend throughout the subsurface environment. The retention of DTDMAC/DSDMAC was believed to be by ion exchange within the clay interlayer basal spaces. Samples collected from the field showed concentrations of DTDMAC to range from approximately 60 mg/kg in the tile field gravel to <2 mg/kg within 10 cm of soil below the tile field gravel. Concentrations of LAS were approximately 20 mg/kg in the tile field gravel and diminished to < 1 mg/kg within 5 cm of soil below the tile field gravel. Soil solution and aquifer concentrations of LAS were always <50 μg/L and usually below the detection limit of 10 μg/L in the aquifer. Concentrations of DTDMAC in the aquifer were below the limit of detection (4 μg/L). Mathematical calculations illustrated the importance of biodegradation and sorption as removal mechanisms of these materials in subsurface environments.
Chemical fate and transport in a domestic septic system: Application of a variably saturated model for chemical movement
Authors: Shutter S.B. , Sudicky E.A. , Robertson W.D.
Published: March 2010

A detailed mathematical modeling study of the impact of a single-family septic system on groundwater quality is described. The work served to improve the conceptual understanding of subsurface processes associated with septic systems and lent insight into the fate of septic-system-derived chemicals. Two-dimensional saturated-unsaturated simulations of the chemical plume associated with the septic system were successful in closely matching field observations. Results indicate that the plume has been subject to limited dispersion (or spreading) reflecting the homogeneous nature of the aquifer materials. The sharp concentration gradients along the upper fringe of the plume near the watei table indicate weak vertical mixing and imply limited dilution by recharge water entering the aquifer downgradient of the septic system. Calibrated dispersivities were 10 cm for the longitudinal value (αL) and 1 mm for the transverse vertical value (αT). The movement of reactive chemical constituents present m consumer detergent products entering the septic system was simulated to assess the influence of sorption and biodegrada-tion. The migration of the detergent compounds linear alkylbenzene sulfonate (LAS) and nitrilotriacetic acid (NTA) was found to be controlled mainly by these processes, and the limited movement predicted by the model is consistent with that observed in the field. For a half-life equal to 15 d and a distribution coefficient (Kd) value equal to 1.5 L/kg in the unsaturated zone, LAS was predicted to move <0.5 m from the tile drains. However, chemicals having a significantly longer half-life or those which exhibit limited partitioning to the soil matrix are likely to migrate much further.
Biodehalogenation: Rapid oxidative metabolism of mono- and polyhalomethanes by Methylosinus trichosporium OB-3b
Authors: Bartnicki E.W. , Castro C.E.
Published: March 2010

Resting cells of Methylosinus trichosporium OB-3b grown in the absence of copper salts rapidly oxidize mono- and polyhalomethanes. The order of reactivity of the series is CH3X > CH2X2 ≥ CHX3 (X = CI, Br). Based on halide ion release, the half-life for methyl bromide and methyl chloride is 9.4 min with a cell density of 0.1 g/ml. The dihalomethanes and bromo-form react at the same rate and half as rapidly as the methyl halides. Chloroform is converted to carbon dioxide at one-fourth the methyl halide rate (t1/2 = 38 min). No isotope effect was observed with either deuteromethylene chloride or deuterochloro-form (CD2Cl2, CDCl3). In all cases, the dehalogenation chemically follows an oxygen insertion into the CH bond, and the final product is carbon dioxide (HCO3−). All reactions are inhibited by acetylene, establishing methane monooxygenase as the responsible enzyme. Incubations with 13CHCl3, 13CH2Br2, and 13CH3Br and nuclear magnetic resonance (NMR) analysis of reaction mixtures showed the first hydrolytically stable products from CHCl3 (HCO3−) and CH2Br2 (CO), but neither formaldehyde nor formate could be detected as intermediates with methyl bromide by this method. The oxidative destruction of halo-methanes by this methylotroph is rapid and not very sensitive to structure.
Effects of freshwater petroleum contamination on amphibian hatching and metamorphosis
Authors: Mahaney Patricia Ann
Published: March 2010

This study examined the effects of freshwater petroleum contamination on amphibian reproduction The primary objectives were to assess the potential environmental and physiological impacts of runoff petroleum products on amphibians, using the green treefrog (Hyla cinerea) as a target species and engine crankcase oil as a contaminant Egg hatching success, tadpole growth, and successful metamorphosis were measured in four concentrations of oil The effects of oil on food source was also studied Hatching success was not measurably influenced by the presence of oil Tadpole and alga growth were negatively associated with the presence of oil No tadpoles from the high concentration of oil treatments successfully metamorphosed
Effects of fenitrothion on memory for cache-site locations in black-capped chickadees
Authors: Mineau Pierre , Boag Peter T. , Beninger Richard J.
Published: March 2010

The effect of femtrothion on food caching in the black-capped chickadee was investigated Oral doses of femtro-thion calculated to produce peak brain inhibition levels of 50 to 60% had no effect, or possibly even improved the ability of the birds to retrieve existing food cache memories when administered after cache locations had been memorized In the more extreme cases, birds were able to remember cache sites even when their physical abilities were still visibly impaired The same dose of femtrothion administered to the birds before they were allowed to cache improved cache-recovery performance This result is consistent with results we obtained at lower brain ChE inhibition levels with physostigmine (reported elsewhere) It is inconsistent with studies that indicate that dosing with anti ChEs typically gives rise to a U-shaped response with impairment at the higher dose levels
Rat liver mitochondrial and microsomal tests for the assessment of quinone toxicity
Authors: Bramble Lisa A , Boardman Gregory D , Dietrich Andrea M. , Bevan David R
Published: March 2010

Short term toxicity tests using mitochondrial and microsomal metabolism were developed and applied to a series of eight quinones In the mitochondrial assay, the degree to which test compounds inhibited mitochondrial respiration varied from an effective concentration (EC50) of 9 to 125 μM In the microsomal assay, the maximum percentage of increase over control oxygen consumption rates elicited by the quinones ranged from 8 to 837% The ability of the compounds to stimulate microsomal oxygen uptake reflects their capability to redox cycle and form reactive oxygen species Results of the mitochondrial and microsomal assay were statistically correlated with several quinone physicochemical parameters and qualitatively compared to reduction potential The biological response observed in both test systems appeared to be most strongly influenced by the re duction potential of the quinone Biomechanisms of action were suggested on the basis of this relationship To assess the abil lty of the mitochondrial and microsomal assays to indicate toxicity of the quinonoid compounds, results were statistically correlated with literature derived toxicity data It was concluded that the mitochondrial assay appears to be a valid indicator of acute tox lcity, whereas the microsomal assay better portends the potential for chronic toxicity
Effects of three pesticides on Poecilus cupreus (coleoptera: carabidae) at different post-treatment temperatures
Authors: Heimbach U. , Baloch A A
Published: March 2010

The influence of post-treatment temperatures of 5, 10, 17 5, and 25°C on the efficacy of three pesticides, Karate (10 g a i/ha lambda cyhalothnn), Sumicidin 10 (30 g a i/ha fenvalerate), and Afugan (294 g a i/ha pyrazophos), applied to Poecilus cupreus (Coleoptera Carabidae) was investigated in the laboratory The results indicate a negative correlation between the temperature and the effects of all three products With the two pyrethroids Karate and Sumicidin, the recovery period of knocked down beetles and their food consumption showed this negative temperature correlation The reason seems to be a temporarily arrested detoxification of the pyrethroids inside the beetles at reduced temperatures Final mortality seven weeks after application of pyrethroids was unaffected by temperature With the organophosphorus compound pyrazophos final mortality was negatively correlated with temperature Male beetles seemed to be more sensitive than females with all products and temperatures