bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioindicators of contaminant exposure and sublethal effects: Studies with benthic fish in puget sound, Washington
Authors: Stein John E. , Collier Tracy K. , Reichert William L. , Casillas Edmundo , Hom Tom , Varanasi Usha
Published: March 2010

A suite of chemical and biochemical variables responsive to contaminant exposure was measured in three species of benthic flatfish (English sole, Parophrys vetulus, rock sole, Lepidopsetta bilineata, and starry flounder, Platichthys stellatus) sampled from up to five sites in Puget Sound, Washington, to assess the sensitivity of the parameters to differences in levels of contaminant exposure The examined indexes were levels of (a) polychlorinated biphenyls (PCBs) in liver, (b) fluorescent aromatic compounds in bile, (c) hepatic aryl hydrocarbon hydroxylase and ethoxy-resorufin O deethylase, (d) total hepatic GSH and (e) hydrophobic DNA xenobiotic adducts in liver as measured by 32P postlabeling The sediment concentrations of PCBs and the sum of selected polycyclic aromatic hydrocarbons at the sampling sites ranged from 21 to 570 and 21 to 5,300 ng/g wet weight sediment, respectively The results showed (a) that all the examined indexes could discriminate among sites exhibiting different degrees of chemical contamination, (b) that species differed in the range of response of most of the measured indexes, and (c) that the use of the indexes in concert appeared to enhance the assessment of contaminant exposure and sublethal effects
Genotoxicity of 2,4,5-trichlorophenoxyacetic acid biodegradation products in the Salmonella reversion and lambda prophage-induction bioassays
Authors: George S. Elizabeth , Whitehouse Douglas A. , Claxton Larry D.
Published: March 2010

Pseudomonas cepacia strain AC1100 has been isolated and reported to utilize 2,4,5-trichlorophenoxyacetic acid (2,4,5 T) as sole carbon and energy source Metabolites from the 2,4,5-T degradation pathway were tested for their mutagenicity in the Salmonella reversion bioassay and genotoxicity in the prophage-induction bioassay The parental compound (2,4,5-T) and three reported metabolites (2,4,5 trichlorophenol, 2,5-dichlorohydroquinone, and 2-chlorosuccinate) were negative with and without metabolic activation in Salmonella typhimurium strains TA98, TA100, TA102, and TA104 Conversely, 2,4,5-T and 2,4,5 trichlorophenol were positive in the prophage-induction bioassay with added S9 2,4,5-Trichlorophenol was approximately 100 fold more genotoxic than 2,4,5-T 2,5-Dichlorohydroquinone was a weak direct-acting genotoxicant in this assay In order to determine if strain AC1100 eliminated genotoxicity, 2,4,5 T medium was inoculated and the genotoxicity and the amount of 2,4,5-T remaining were examined over the growth period As cell numbers increased, the percentage of 2,4,5-T remaining in the medium decreased This decrease coincided with a decrease in genotoxicity in the prophage-induction bioassay No mutagenic response was observed in the Salmonella reversion assay
Performance characteristics of effluent toxicity tests: Summarization and evaluation of data
Authors: Parkhurst Benjamin R. , Warren-Hicks William , Noel Lynn E.
Published: March 2010

With increased use of toxicity testing for monitoring effluent toxicity, it is important to evaluate the precision of effluent toxicity tests To address this need, we identified, compiled, summarized, and evaluated published and unpublished data from intralaboratory and interlaboratory studies on the variability of acute and chronic effluent toxicity tests for single chemicals and effluents A total of 23 published and unpublished reports were identified The most extensive data on test variability are available for acute tests with Daphnia spp, Pimephales promelas, and Mysidopsis bahia and chronic tests with Pimephales promelas, Ceriodaphnia dubia, and Cyprinodon variegatus All other tests have considerably fewer data Data on which to evaluate the variability of toxicity tests produced by the most current U S Environmental Protection Agency methods are not extensive Mean C V s for intralaboratory studies (7-33%) were smaller than those for interlaboratory studies (34-46%) However, mean intra and interlaboratory C V s for chronic tests (7-38%) were generally equal to or smaller than those from acute tests (17-46%) Also, C V s from single chemical tests (32-46%) were generally larger than those from effluent tests (7-34%)
Lead, cadmium, selenium and mercury in seabird feathers from the tropical mid-pacific
Authors: Burger Joanna , Schreiber Elizabeth Anne E. , Gochfeld Michael
Published: March 2010

We compared the levels of lead, cadmium, selenium, and mercury in adults of several species of seabirds nesting on Manana Island off Oahu, Hawaii, and on Sand and East islands, Johnston Atoll, in 1990 Examined species included sooty tern (Sterna fuscata), brown noddy (Anous stolidus), wedge-tailed shearwater (Puffinus pacificus), brown booby (Sula leucogaster), and redfooted booby (S sula) For both locations and all metals we found significant interspecific differences There were some consistent patterns within sites selenium levels were two to three times higher in brown noddies compared to the other species, mercury levels in wedge tailed shearwaters were two to five times higher than those in sooty terns or brown noddies, but were similar to levels in boobies Cadmium levels were generally low The significant interspecific differences in metal levels indicate that the levels for some species may not be background levels Hawaiian sooty terns had higher lead levels than those from Johnston, but the noddies had higher selenium and mercury levels and shearwaters had higher lead and mercury levels on Johnston Sooty terns and brown nod dies had higher lead levels in Hawaii and Johnston Atoll than in Australia or the Caribbean
Effects of food and water quality on culturing of Ceriodaphnia dubia
Authors: Cooney J.D.C. , Pollock T.L. , Degraeve G.M. , Moore E.L. , Palmer W.D.
Published: March 2010

The U.S. Environmental Protection Agency (EPA) has developed a 7-d test to evaluate effluent effects on Ceriodaphnia dubia survival and reproduction. Several foods have been used to culture and test Ceriodaphnia dubia in both laboratory waters and surface waters with variable results. This study's objective was to evaluate effects of eight diets on survival and reproduction of Ceriodaphnia dubia in hard reconstituted water (HRW); HRW was used alone or supplemented with bacteria or selenium to determine whether their addition would improve survival and reproduction. Diets consisted of yeast, trout food (TF), yeast/trout food/Cerophylc̊ (YTC), Selenastrum capricornutum, Ankistrodesmus convolutus, Chlamydomonas reinhardii, Selenastrum capricornutum plus TF, and Selenastrum capricornutum plus YTC. Screening tests in HRW with each diet (at several levels) were first used to rank diets; diets with high survival (®80% at 14 d) and reproduction (®3 young per female per reproductive day) were further evaluated in multigeneration feeding tests. Finally, diets yielding high survival and reproduction in HRW were evaluated in surface and well water to verify adequacy in waters of differing composition and quality. Yeast, trout food, YTC, Selenastrum capricornutum, Ankistrodesmus convolutus, or Chlamydomonas reinhardii used alone were unacceptable for long-term culturing in HRW under test conditions used in this project. Success of the EPA's recommended food, YTC, was dependent on water, with worst results in HRW. The addition of selenium and bacteria to the HRW did not consistently improve either survival or reproduction of Ceriodaphnia dubia in the diet tests. Some of the diet test results were confounded by the use of batches of HRW that periodically contained some unidentified components that were toxic to Ceriodaphnia dubia. Both Selenastrum capricornutum plus TF and Selenastrum capricornutum plus YTC were acceptable for culturing with high survival and reproduction.
Infrared spectroscopy-based property-reactivity correlations for predicting environmental fate of organic chemicals
Authors: Collette Timothy W.
Published: March 2010

A conventional structure-activity relationship (SAR) has been established between the alkaline hydrolysis rate constants (koh) of 12 alkyl and aryl formates and acetates and the linear combination of the frequencies of the C=o and C—o infrared (IR) absorbance peaks. The inability of this relationship to predict koh values for more structurally diverse carboxylic acid esters led to the development of a prototype of a prediction system that employs multiple linear regression analysis, using points from the Fourier transforms (FTs) of IR spectra. Conventional SARs have also been observed between single IR peak parameters and the microbial degradation rate constants of amides (C=O peak frequencies), 2,4-dichlorophenoxyacetate esters (CH peak intensities), phenols (OH peak frequencies), and anilines (NH stretching peak intensities). These observations indicate the feasibility of extending the FT-based prediction system to microbial degradation when reliable rates are available for additional compounds.
Toxicokinetic modeling of mixtures of organic chemicals
Authors: McCarty L. S. , Dixon D. G. , Ozburn G. W. , Smith A. D.
Published: March 2010

A residue-based one-compartment, first-order-kinetics model (1CFOK) was used to investigate the toxicity of mixtures of organic chemicals to the American flagfish, Jordanella floridae. Four sets of chemicals (chloroethanes, chloroethylenes, chlorobenzenes, and chlorophenols) were used to examine within-set mixtures. Component chemicals of the mixtures appeared to be simply additive at threshold LC50. Kinetics rate constants and critical body residue (CBR) data estimated from single chemical toxicity test data, along with bioconcentration factor information calculated from log Kow, were used to model the time course of toxicant action of the mixtures and compare them against independently observed mixture toxicity test results. Agreement between observed and modeled information was good, in terms of both threshold toxicity estimates and the time course of toxicant action.
Historical declines and diebacks of central European forests and present conditions
Authors: Kandler Otto
Published: March 2010

Human activities had reduced the central European forested area to less than 20% by the end of the Middle Ages but increased it again to 30% of the original area during the industrial period. Detailed reports on declines and diebacks have been available since the 18th century. Beginning in the second half of the 19th century, in highly industrialized areas, smoke damage occurred until effective measures were taken to lower SO2 concentrations. Almost complete recolonization of devastated areas by conifers has been observed since the 1960s, with few exceptions, for example, the Ore Mountains in Czechoslovakia. The suggestion that a large-scale decline of European forests (Waldsterben) has taken place since 1979/1980 is not corroborated by 10 years of intensive research. Annual surveys fail to show the expected increase in foliage deficit, a shift from lower to higher damage classes, an increase in mortality, or increasing growth depression in recent decades. No correlation between the spatial and temporal distribution of air pollutants and damage classes has been found. Comparison of old and new photographs and evaluation of old studies on leaf indexes show that similar patterns of crown conditions caused by fluctuating site conditions and diseases have always occurred to a similar extent. Thus, Waldsterben may be understood as a problem of new awareness of old and only partly explained phenomena.
The toxicity of sulfur to microtox® from acetonitrile extracts of contaminated sediments
Authors: Jacobs Mark W. , Delfino Joseph J. , Bitton Gabriel
Published: March 2010

Toxicity bioassays of solvent extracts of sediments are used to evaluate the toxicological effects of extracted hydrophobic organic contaminants. However, this type of bioassay assesses the toxicity of all extracted compounds, natural or anthropogenic. Sediment extracts are typically subjected to cleanup procedures before chemical analysis to remove interfering, coextracted substances. This study evaluated the effect of cleanup procedures on the toxicity of acetonitrile extracts of contaminated sediments by using the Microtox® bioluminescence bioassay. Extract cleanup significantly reduced toxicity of most extracts when copper powder was added to remove coextracted sulfur. Microtox was shown to be highly sensitive (EC50 of 24.7-35.8 μg/L) to elemental sulfur dissolved in several organic solvents. Toxicity tests utilizing solvent extracts of sediments must take into account the toxic effects of coextracted sulfur on bioassay organisms to accurately assess the environmental impacts of extracted hydrophobic contaminants.
Use of three artificial sea salts to maintain fertile sea urchins (arbacia punctulata) and to conduct fertilization tests with copper and sodium dodecyl sulfate
Authors: Neiheisel Timothy W. , Young Melba E.
Published: March 2010

Fertile sea urchins were maintained over six months in three commercial artificial sea-waters (Forty Fathoms®, HW Marinemix®, and Instant Ocean®). Fertilization tests using the reference toxicants copper (Cu) and sodium dodecyl sulfate (SDS) were conducted with the sea urchins in the artificial sea salt in which the organisms were maintained. The ranges of Cu and SDS no-observed-effect concentrations (NOECs) for the tests in the three artificial seawaters overlapped one another and also the ranges of published results for animals maintained and tested in natural sea-water. The 50% effect concentration (EC50) values of Cu for the tests using the three artificial sea-waters were not significantly different. The EC50 value for SDS using HW Marinemix was significantly lower than values for tests using the other artificial seawaters. The artificial seawaters were judged acceptable for maintaining Arbacia punctulata and conducting fertilization tests, although additional research is required to optimize long-term maintenance of fertile animals.
Uptake and accumulation of selenium by terrestrial plants growing on a coal fly ash landfill. Part 3. Forbs and grasses
Authors: Arthur Mary A. , Schneider Robert E. , Weinstein Leonard H. , Rubin Gail
Published: March 2010

Plants grown on coal fly ash landfills can accumulate relatively high concentrations of selenium (Se), which may be ameliorated with gypsum application to the soil. In 1988 and 1989, experiments were conducted to measure the accumulation of Se in forbs and grasses growing on a coal fly ash landfill. In 1990, a dose-response study was conducted to determine whether forbs and grasses growing on a fly ash landfill would respond to gypsum applications with reduced tissue levels of Se and increased levels of S. Higher concentrations of Se were found in plants grown on the landfill than on nonlandfill control plots, and leguminous species tended to accumulate more Se than nonlegumes. Two of the four studied species—bird's-foot trefoil (Lotus corniculatus L.) and bitterweed (Picris hieracioides L.)—had higher concentrations of S when grown with gypsum. However, only bird's-foot trefoil showed significantly reduced Se. The difference in tissue levels of Se and S was a presence/absence response, not a monotonic response to the rate of applied gypsum. Although it is clear that gypsum applications have the potential for mitigating Se uptake by some plants, the response is quite variable on a fly ash landfill, probably due to variability in concentration and availability of Se in the soil cap.
Physiological effects of red phosphorus smoke inhalation on prairie dogs and rock doves
Authors: Johns Brad E. , Thompson R. D. , Crane Kenneth A.
Published: March 2010

Pulmonary function, blood chemistry, and hematology studies were conducted with prairie dogs (Cynomys ludovicianus) and rock doves (Columba livia) under resting conditions to assess environmental risk of exposing wildlife species to multiple applications of red phosphorus/butyl rubber smoke (0.0, 1.0, and 4.0 mg/L). Four daily 80-min smoke exposures had no significant physiological effect on prairie dogs. However, with rock doves, two daily 80-min smoke exposures resulted in elevated respiratory frequency in two males followed by death, a significant concentration × day effect on carbon dioxide production, respiratory exchange ratio, metabolic rate, lymphocytes, and heterophiles, and a significant sex × concentration effect on hemoglobin and methemoglobin. Although results showed that rock doves are more vulnerable to red phosphorus/butyl rubber smoke than prairie dogs, it appears that exposure to the smoke is unlikely to pose a significant risk to either species under field conditions.
Free and conjugated concentrations of nine resin acids in rainbow trout (Oncorhynchus mykiss) following waterborne exposure
Authors: Niimi A. J. , Lee H. B.
Published: March 2010

Rainbow trout (Oncorhynchus mykiss) were exposed to nine resin acids that included abietic, dehydroabietic, chlorodehydroabietic, dichlorodehydroabietic, neoabietic, pimaric, isopimaric, sandaracopimaric, and palustric acids. Bioconcentration factors (BCFs) for these acids ranged from <25 to 130 among fish that were exposed to mean waterborne concentrations of 0.7 to 3.6 μg/L for 20 d. Total free and conjugated acid concentrations ranged from 1 to 3 mg/kg on a wholebody basis. There was a significant relationship (P < 0.01) between decreasing percentage of conjugated/total acid and increasing BCF. Elimination rates were also monitored over a 10-d period, although no detectable levels were observed. Based on initial chemical concentrations, it was concluded that the half-lives of these acids were <4 d.
Extracts from settling particulate matter collected in the Stockholm archipelago waters: Embryolethality, immunotoxicity and erod-inducing potency of fractions containing aliphatics/monoaromatics, diaromatics or polyaromatics
Authors: Veilens Emilie , Brunström Björn , Broman Dag , Näf Carina , Zeböhr Yngve , Dencker Lennart
Published: March 2010

Bioassays previously used for evaluating the toxic potency of specific compounds as well as mixtures proved useful for testing extracts of environmental samples. Samples of settling seston, that is, settling particulate matter in water, were collected with sediment traps placed in the Stockholm archipelago. The samples were Soxhlet extracted with toluene, the extracts run through an Si column, and the eluates separated by HPLC into (a) aliphatics and monoaromatics, (b) diaromatics (e.g., polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs] and polychlorinated biphenyls [PCBs]), and (c) polyaromatics. Toxic potency was evaluated in terms of mortality in chick embryos, induction of 7-ethoxyresorufin-O-deethylase (EROD) in chick embryos, inhibition of lymphoid development in chick embryo bursae, and inhibition of lymphoid development in mouse thymus anlagen in vitro. The polyaromatic fraction from seston collected at a location (inner archipelago) close to the center of Stockholm was the most potent of the tested fractions. The polyaromatic fractions were analyzed to determine their contents of 15 polycyclic aromatic hydrocarbons (PAHs) that had previously been toxicity tested. The concentrations of these PAHs were too low to explain the toxicities of the polyaromatic fractions. The diaromatic fraction from the inner archipelago was about four- to fivefold less potent as an EROD inducer and at inhibiting lymphoid development in mouse thymus anlagen in vitro, compared with the polyaromatic fraction from this location. Analysis of PCDD/Fs and three coplanar PCBs in this diaromatic fraction revealed that these compounds were responsible only for a minor part of the toxicity of the fraction.
Toxicity of endosulfan to native and introduced fish in Australia
Authors: Sunderam R. I. M. , Thompson G. B. , Cheng D. M. H.
Published: March 2010

Semistatic bioassays of endosulfan with native and introduced Australian fish indicated that they are sensitive to this insecticide at low concentrations. The introduced European carp (Cyprinus carpio) was the most sensitive species, with a measured 96-h LC50 of 0.1 μg/L, whereas the native eastern rainbow fish (Melanotaenia duboulayi) and silver perch (Bidyanus bidyanus) were the least sensitive, with measured 96-h LC50 values of 2.4μg/L. The measured 96-h LC50 values of endosulfan for bony bream (Nematolosa erebi), golden perch (Macquaria ambigua), and rainbow trout (Oncorhynchus mykiss) were 0.2, 0.5, and 1.6 μ/L, respectively. Toxicities of endosulfan in Sydney mains water and Mehi River water were similar when rainbow fish, golden perch, and silver perch were used as test animals. The initial measured concentration was about 42% of the nominal concentration, whereas final measured concentration after 24 h in semistatic tests declined to 5.6% of the nominal concentration. The toxicity of endosulfan was similar in Australian native and introduced fish and in overseas fish, but varied markedly with test method. The 96-h LC50 values for one species, the rainbow fish, varied from 0.5μg/L when reported as measured concentrations in a flow-through test to 11.4 μg/L as nominal values in a static test. These differences span much of the variation found in 96-h LC50 values for all fish species described in the world literature.
Granular insecticides and birds: Factors to be considered in understanding exposure and reducing risk
Authors: Best Louis B. , Fischer David L.
Published: March 2010

Granular insecticides are used extensively, and many are highly toxic to birds. Here we discuss potential routes of avian exposure to granular insecticides and factors influencing those routes, suggest possible corrective measures for reducing exposure, and identify areas of needed research. Potential routes of exposure include inhalation or dermal absorption, inadvertent ingestion of granules, ingestion of prey or plant material containing pesticide residues, mistaking granules for food, and consuming granules as a source of grit. Bird consumption of granules for grit depends on factors affecting availability, bird behavior, grit/granule characteristics preferred by birds, and grit/granule retention in the gizzard. Avian exposure to granular insecticides may be reduced by taking into account factors such as application rate/incorporation of granules, habitat-use patterns of birds, granule integrity in the field, rate of release of insecticide from the granules, and consumption of granules as a source of grit or food. Altering certain physical characteristics of insecticide granules may reduce avian exposure; these include granule size, shape and surface texture, composition, color, and insecticide load. Research needs include evaluations of the U.S. Environmental Protection Agency's current granular risk index, the relative importance of the various potential routes of exposure, grit-use patterns of birds, and bird habitat use and behavior in treated fields.
The biological significance of contaminants in sediment from hamilton harbour, Lake Ontario
Authors: Krantzberg Gail , Boyd Duncan
Published: March 2010

Sediment from regions within Hamilton Harbour is highly contaminated with metals and polyaromatic hydrocarbons (PAHs); nevertheless, macroinvertebrates are present in situ and not all contaminated sites were toxic to laboratory organisms. Most sediment did elicit sublethal and/or lethal responses in bioassay species. Results of analyses of tissue residues in bioassay organisms, and the amelioration of toxicity by chemical treatments, implicate trace metals as contributing to sediment toxicity. Sediment oxygen demand, however, apparently contributed to the restricted benthic community in situ and some of the toxicity observed in vitro. In addition, for some stations there was evidence that PAHs were responsible for the detected deleterious effects. The study concluded that the suitability for colonization by benthic invertebrates of sediment in some areas of Hamilton Harbour is apparently limited both by contaminants and by high sediment oxygen demand. Remedial options aimed at eliminating oxygen depletion of the bottom waters of the harbor should result in improvements in the benthic invertebrate community directly, by providing a suitable oxygen regime for organisms less tolerant of temporal anoxia, and indirectly, by decreasing metal bioavailability, possibly through the coprecipitation of trace metals with iron hydroxides. The use of chemical treatments in sediment bioassays provides a technique for evaluating the source of sediment-associated toxicity.
Relationships between physiological and fish population responses in a contaminated stream
Authors: Adams S. Marshall , Crumby W. Dennis , Greeley Mark S. , Ryon Michael G. , Schilling Elizabeth M.
Published: March 2010

Relationships between toxicant exposure, physiological effects, and population-level responses were investigated in redbreast sunfish (Lepomis auritus) from a stream receiving chronic inputs of mixed contaminants. Elevated levels of detoxification enzymes, which provided evidence of direct toxicant exposure, were associated with low lipid levels, histopathological damage, and reduced growth for fish at the upper three sites in the contaminated stream. Decreased fecundity, exhibited by fish at the upper site, might have been due to the reduced capacity of the liver to manufacture yolk proteins. Reduction in lipid pools due to metabolic drains might have decreased the amount of physiological useful energy needed for growth resulting in smaller age-specific sizes of fish at the upper three sites. This approach for investigating relationships between contaminant exposure, physiological effects, and population-level responses such as growth and size distributions could serve as a model for designing biomonitoring studies and for stimulating further research to improve our ability to evaluate the ecological significance of chronic contaminant stressors on aquatic ecosystems.
Biodegradation of acrylonitrile in soil
Authors: Donbero Phyllis A. , Odelson David A. , Klecka Gary M. , Markham Daniel A.
Published: March 2010

The aerobic biodegradation of [14Clacrylonitrile at concentrations ranging from 10 to 1,000 ppm was examined in a variety of surface soils. At concentrations up to 100 ppm, complete degradation of the compound occurred in <2 d in a Londo soil. Greater than 50% of the radioactivity was recovered as [14C]carbon dioxide following 6 d of incubation. Because the soil had no known previous exposure to acrylonitrile, dissimilation did not appear to require acclimation of the microorganisms. Transient formation of acrylamide and acrylic acid as intermediates of degradation was also observed. These results appear to be consistent with previously published results of acrylonitrile transformation by axenic microbial cultures. Similar results were obtained in studies conducted with Tappan loam (10, 50, 100 ppm) and sand (10 and 50 ppm). Acclimation of the microorganisms was required before degradation of 100 ppm acrylonitrile in sand. Degradation of higher concentrations (500 and 1,000 ppm in Londo soil) was relatively slow and may be due to inhibitory effects of the parent compound.
Competition potentials of environmentally applied bacteria with human fecal microbiota
Authors: Nelson Gail M. , Claxton L. D. , Creason J. P. , George S. E.
Published: March 2010

One of the potential human health effects associated with the environmental release of microorganisms is colonization of the intestinal tract. This study uses serial transfer techniques to monitor the in vitro survival and competition with human fecal microbiota of Pseudomonas aeruginosa strains BC16 and AC869. Strain BC16 was isolated from a commercial product for polychlorinated biphenyl (PCB) degradation, and AC869 is a 3,5–dichlorobenzoate degrader. In addition, a mouse intestinal isolate, Pseudomonas aeruginosa strain PAMG, was studied as a positive control. Results were compared to previously published mouse fecal microbiota studies. Quantitative comparison of the fecal microbiota populations enumerated on selective media found human and mouse cultures to be nearly identical. Survival of the competitor strains was also similar in both the human and the mouse systems. By culture 5 of the human serial transfer experiments, strains AC869 and PAMG were present at significantly higher levels than strain BC16. In previous serial transfer experiments with mouse fecal flora, strain AC869 was present at a higher level than strains PAMG and BC16 by culture 5. No alterations of the microbiota populations due to the addition of a competitor strain were found. This system can be helpful in identifying environmental strains with a high potential for colonizing the intestinal tract.
Effects of bleached kraft mill effluent on fish in the St. Maurice River, Quebec
Authors: Hodson Peter V. , Thivierge Denis , Levesque Marie-Claude , McWhirter Michelle , Ralph Karen , Gray Bruce , Whittle D. Michael , Carey John H. , Van Der Kraak Glen
Published: March 2010

Tissue levels of chlorinated dioxins and furans and the physiological and biochemical responses of fish were measured upstream and downstream of a bleached kraft mill in the St. Maurice River, Quebec. Relative to fish 10 km upstream of the source, white suckers (Catostomus commersoni) downstream showed evidence of chemical exposure, chemical metabolism, stress, and altered energy use. Levels of 2,3,7,8–tetrachlorodibenzo-p-dioxin and tetrachlorodibenzofuran in gutted whole fish averaged 23 and 260 pg/g immediately downstream of the plant and declined to 18 and 112 pg/g at 95 km downstream. The activity of hepatic aryl hydrocarbon hydroxylase (AHH) was 10X higher immediately downstream and 5X higher 95 km downstream. There were corresponding increases in relative liver size, hematocrit, serum glucose, serum protein, and fin-ray asymmetries, with a pattern of response that matched enzyme induction. These responses pointed to a strong effluent effect and followed the patterns of tissue contamination by dioxins and furans and of water contamination by chlorinated phenolics and guaiacols. There were strong correlations between AHH induction and tissue contamination. Whereas lipid levels increased at all downstream sites, condition factor decreased at 95 km from the source, indicating that there may be disturbances in energy metabolism. Effects on sexual maturation, as shown by levels of serum hormones and gonad somatic index, were inconclusive.
Distribution and metabolism of polycyclic aromatic hydrocarbons (PAHs) injected into eggs of chicken (Gallus domesticus) and common eider duck (Somateria mollissima)
Authors: Näf Carina , Broman Dag , Brunström Björn
Published: March 2010

The present study focuses on the uptake, distribution, and metabolism of 16 polycyclic aromatic hydrocarbons (PAHs) injected into eggs of chicken (Gallus domesticus) and common eider (Somateria mollissima). Of the total dose of 0.2 ppm, injected on day 4 of incubation, 94% was metabolized within the chicken egg by day 18. The gallbladder showed the highest PAH concentrations of the analyzed organs/structures (gallbladder, liver, kidney, adipose tissue) of the chick and eider embryos. The proportion of the total PAH content present in these organs/structures was higher in the eider embryo (40%) than in the chick embryo (16%). Chick embryos, eider embryos, and wild juvenile eiders had similar PAH concentrations and PAH profiles. The characteristics of this “PAH pool” seemed to be largely unrelated to the relative concentrations of the PAHs to which the birds were exposed, the age of the organisms, and the routes of exposure. The largest studied PAH molecule, coronene, was not taken up from the yolk by the embryo as efficiently as the other PAHs, but once taken up it was metabolized as readily as the others. Basal aryl hydrocarbon (benzo[apyrene) hydroxylase (AHH) activities of chick and eider embryos were of similar magnitude.
Terrestrial wildlife exposed to agrochemicals: An ecological risk assessment perspective
Authors: Kendall Ronald J. , Akerman J.
Published: March 2010

Ecological risk assessment of wildlife exposed to agrochemicals addresses hazard and exposure to at least qualify and attempt to quantify the ecological risk. To accomplish a present-day ecological risk assessment in wildlife toxicology, data must be available from several disciplines: annlytical toxicology/environmental chemistry, biochemical toxicology, and wildlife ecology/ecotoxicology. This interdisciplinary approach, essential in wildlife toxicology for the assessment of the chemical effects on the reproduction, health, and well-being of wildlife, makes it difficult to rapidly generate the data necessary for ecological risk assessments. However, as the field has evoloed, it has become clear that interdisciplinary cooperation is critical to provide the complex data sets required for the registration and reregistration of pesticide products by the U.S. Environmental Protection Agency. The science of ecological risk assessment for terrestrial wildlife exposed to agrochemicals advanced rapidly during the decade of the 1980s and into the 1990s. The ecological risk assessment process will continue to improve as a result of improved data sets available for conduct of such assessments. Addressing the ecological risks associated with the use of an agricultural chemical involves a complex array of laboratory and field studies, in essence, a research program.
The role of models in ecological risk assessment: A 1990's perspective
Authors: Barnthouse Lawrence W.
Published: March 2010

Previously published reviews of mathematical models available for ecological risk assessment have emphasized population and ecosystem modeling approaches originally developed 20 years ago or more. Discussions of applications have focused on quantifying ecological effects of toxic chemicals and pesticides. This review emphasizes (a) modeling approaches developed within the last decade; (b) applications to a broad array of environmental problems on local, regional, and global scales; and (c) the relevance of different types of models to different components of the risk assessment process.
Biological and abiotic losses of polynuclear aromatic hydrocarbons (PAHs) from soils freshly amended with sewage sludge
Authors: Wild S.R. , Jones K.C.
Published: March 2010

Sewage sludge containing typical indigenous concentrations of polynuclear aromatic hydrocarbons (PAHs) was applied to several different soils in glass microcosms. Biologically active and sterilized soils were monitored for PAH content over a period of approximately 205 d. Agricultural soils with and without previous exposure to sewage sludge were tested, together with a forest soil and a soil from a major roadside. Loss of PAHs from a soil spiked with a PAH standard solution was also investigated. Results indicate the PAH compounds with less than four benzene rings are susceptible to abiotic loss processes. However, losses by these mechanisms were insignificant for compounds with four or more benzene rings. Half-lives for the sludge-applied PAHs were derived and indicated a strong dependence of persistence on chemical structure. Half-lives for phenanthrene and benzo[gle]perylene were between 83 and 193 d and 282 and 535 d, respectively. Mean half-lives correlate directly with log Kow and inversely with log water solubility. Behavior of PAHs was different in each soil, probably due to different soil characteristics and history of PAH exposure. The soil spiked with PAHs provided the lowest half-life values for most PAH compounds, suggesting a higher susceptibility of spiked PAHs to both abiotic and biological degradation.
Pesticide concentration patterns in agricultural drainage networks in the lake Erie Basin
Authors: Richards R. Peter , Baker David B.
Published: March 2010

This paper presents information on pesticide concentrations in Lake Erie tributaries draining agricultural watersheds, information distilled from data sets spanning nearly a decade and including up to 750 samples per tributary. Pesticide concentrations are strongly skewed and approximately lognormal. Average concentrations in tributaries are correlated with the amount applied in the basin, but with important secondary effects from chemical properties and modes of application of the pesticides. During runoff of storm events following application, concentrations rise rapidly, peak about the time of peak discharge, and decline slowly thereafter. These patterns do not match those for nutrients, major ions, or sediment, indicating a different pathway from the fields for pesticides. On an annual basis, elevated monthly average concentrations are usually observed from May to August, and low concentrations are present during the rest of the year. Monthly average concentrations of atrazine and alachlor generally exceed maximum contaminant levels (MCLs) in at least one month following application, but those of other herbicides do not. Annual averages are below MCLs for all compounds. No long-term trends are apparent. Comparisons of patterns in large and small tributaries show that small tributaries have higher maximum concentrations, more frequent concentrations below detection limit, and fewer intermediate concentrations. Smaller tributaries have more strongly skewed distributions and much greater temporal variability in concentrations than do larger rivers.
The aqueous photolysis of triclopyr
Authors: Woodburn Kent B. , Batzer Fred R. , White Frank H. , Schultz Mark R.
Published: March 2010

The aqueous photolysis of triclopyr was examined in both pH 7-buffered water and natural river water under artificial lights and midsummer sunlight (40°N latitude). The pseudo-first-order half-lives in pH 7-buffered water and natural river water averaged 0.5 and 1.3 d, respectively, at 25°C. Diffuse mercury lamps and midsummer sunlight produced similar rates of triclopyr decay and photoproduct distribution for a given solution. The photolysis of untreated river water produced a significantly different distribution of photoproducts compared to sterile, pH 7-buffered water. The photolysis of triclopyr in river water generated oxamic acid as the major photoproduct and a number of other low-molecular-weight carboxylic acids as minor products. Photolysis in sterile, pH 7-buffered water produced 5-chloro-3,6-dihydroxy-2-pyridinyloxyacetic acid as the major photoproduct, with minor amounts of oxamic acid and other low-molecular-weight acids.
Bioaccumulation of organic and inorganic selenium in a laboratory food chain
Authors: Besser John M. , Canfield Timothy J. , La Point Thomas W.
Published: March 2010

Aquatic organisms accumulated selenium (Se) from inorganic and organic Se species via aqueous and food-chain exposure routes. We measured aqueous and food-chain Se bioaccumulation from selenate, selenite, and seleno-L-methionine in a laboratory food chain of algae (Chlamydomonas reinhardtii), daphnids (Daphnia magna), and fish (bluegill, Lepomis macrochirus). Selenium concentrations were monitored radiometrically with 75Se-labeled compounds. All three organisms concentrated Se more strongly from aqueous selenomethionine than from either inorganic Se species. Bioconcentration factors (BCFs) estimated from 1 μg Se/L Se-methionine exposures were approximately 16,000 for algae, 200,000 for daphnids, and 5,000 for bluegills. Algae and daphnids concentrated Se more strongly from selenite (BCFs = 220–3,600) than selenate (BCFs = 65–500) whereas bluegills concenrated Se about equally from both inorganic species (estimated BCFs = 13 to 106). Bioaccumulation of foodborne Se by daphnids and bluegills was similar in food chains dosed with different Se species. Daphnids and bluegills did not accumulate Se concentrations greater than those in their diet, except at very low dietary Se concentrations. Food-chain concentration factors (CFs) for daphnids decreased from near 1.0 to 0.5 with increases in algal Se concentrations, whereas CFs estimated from bluegill exposures averaged 0.5 over a range of foodborne Se concentrations. In exposures based on selenite, bluegills accumulated greater Se concentrations from food than from water. Aqueous and food-chain Se uptakes were approximately additive, and depuration rates were similar in aqueous, food-chain, and combined exposures. Our results suggest that bluegills in Secontaminated habitats accumulate inorganic Se species primarily via food-chain uptake, although organoselenium compounds such as Se-methionine may contribute significantly to Se bioaccumulation by bluegills via both aqueous and food-chain uptake.
The effect of ivermectin on the invertebrate fauna associated with cow dung
Authors: McCracken D.I. , Foster G.N.
Published: March 2010

On each of four dates between May and September 1988, ivermectin was mixed into 60 × 1 kg pats of cattle dung, such that each contained 2, 1, 0.5, or 0 mg ivermectin per kilogram. The pats were then placed on pasture in a stratified, random, block plot and exposed for 15, 30, 45, 60, or 90 d. Twelve pats and a soil sample from below each were lifted at the end of these exposure periods and invertebrates extracted from both dung and soil. This study concentrated on the differences between experimental pats with regard to the numbers and types of Diptera and Coleoptera present. A total of 65 taxa were identified, and the data sets obtained for the dung and the soil were analyzed separately, using two multivariate techniques—TWINSPAN and DECORANA. The major factors determining the fauna of the dung pats and of the soil below them were found to be length of exposure on pasture, exposure date, and ivermectin presence/absence. The presence of ivermectin in the dung markedly changed the fauna in and below treated pats, particularly affecting cyclorrhaphan fly larvae. It is suggested that the incorporated multivariate methods have great potential for use in environmental contamination studies, as they analyze complex data sets objectively and allow the identification of faunal characteristics of treated and untreated sites.
Statistical analysis of theCeriodaphniatoxicity test: Sample size determination for reproductive effects
Authors: Oris James T. , Bailer A. John
Published: March 2010

An analysis of sample size requirements for the Ceriodaphnia dubia reproduction toxicity test is presented. Sample size requirements for detecting nominally specified biological effect sizes in the presence of different variance models are examined over a range of false positive error rates (α) and false negative error rates (β). Mean total young produced per female from control organisms in 53 separate toxicity tests yields a mean (22.52) and variance (68.25) that are used in sample size determinations. Results from these calculations demonstrate that in tests using the currently accepted sample size of 10 organisms per concentration, hypothesis-testing techniques are capable of detecting a range of 31 to 100% reproductive inhibition relative to controls. This wide range of minimum detectable inhibition values indicates that the ability to detect biologically significant levels of reproductive inhibition in this test is constrained by the statistical properties (i.e., power) associated with the currently accepted test protocol. It is suggested that the design of the Ceriodaphnia toxicity test be based not only on a minimum level of control reproductive output (as currently recommended), but also on the ability to detect a specified level of reproductive inhibition.
Bioavailability of fluoranthene in freshwater sediment toxicity tests
Authors: Suedel Burton C. , Rodgers John H. , Clifford Philip A.
Published: March 2010

To examine equilibrium-partitioning model predictions of interstitial water concentrations of fluoranthene as part of the equilibrium-partitioning (EqP) approach to sediment quality criteria development, the bioavailability (toxicity) of fluoranthene-amended sediment (a nonpolar organic compound) to Hyalella azteca, Daphnia magna, and Chironomus tentans was determined. Fluoranthene was added to three freshwater sediments with similar organic carbon content (0.44-0.50%). Although sediments were from divergent sources (Water Research Field Station [WRFS], Trinity River [TR], and Lake Fork [LF]), sediment physical and chemical characteristics did not vary appreciably, leading us to hypothesize (based on EqP theory) that fluoranthene-amended sediment toxicity would not vary between sediments. Predicted interstitial water concentrations from the equilibrium-partitioning model were similar to measured interstitial water concentrations for WRFS and TR sediment, but the model underpredicted measured values for LF sediment by a factor of two. EC50s for Daphnia magna, Hyalella azteca, and Chironomus tentans in interstitial water were a factor of two to five greater for LF than for WRFS and TR sediments. Factors other than organic carbon content of sediments (e.g., dissolved organic carbon content in interstitial water) probably contributed to the variability in bioavailability of fluoranthene. Based on 10-d sediment toxicity tests with Hyalella azteca, Daphnia magna, and Chironomus tentans, organic carbon-normalized sediment concentrations were better predictors of toxicity than interstitial water and bulk sediment fluoranthene concentrations. In 10-d aqueous-phase tests with fluoranthene, Chironomus tentans and Hyalella azteca were twice as sensitive as Daphnia magna. The response of freshwater organisms to fluoranthene-amended sediment was similar to that of marine organisms exposed to fluoranthene in other studies. The EqP approach for sediment-quality criteria accurately predicted sediment toxicity for WRFS and TR sediments but not for LF sediment, indicating the model may be overly protective for some bottom sediments. Factors other than organic carbon content may be important in affecting neutral organic compound bioavailability.
Comparative uptake kinetics and transport of cadmium and phosphate in Phleum pratense-Glomus deserticolum associations
Authors: Arnold Paul T. , Kapustka Lawrence A.
Published: March 2010

Mycorrhizal plants (timothy grass, Phleum pratense with Glomus deserticolum) were compared to nonmycorrhizal timothy grass to determine the effect of the mycorrhizal condition on the uptake and transport of cadmium. Companion experiments were conducted to ascertain phosphate uptake kinetics of mycorrhizal and nonmycorrhizal plants. Divalent cation competition experiments also were employed in this study. Comparisons of the high-affinity uptake mechanisms between mycorrhizal and nonmycorrhizal plants identified higher levels of phosphate uptake were due to an increase in the number of uptake sites rather than to differences in affinity. The respective values for Km for high-affinity phosphate uptake were 2.5 ± 1.3 μM P (mycorrhizal) and 3.4 ± 1.3 μM P (non-mycorrhizal), but these values were not statistically different at the α = 0.05 level. High-affinity Cd2+ uptake differed significantly between mycorrhizal (4.5 ± 2.8 μM) and nonmycorrhizal (2.8 ± 1.1 μM) plants. Presence of Ca2+ at 1.0 mM concentration conferred considerable competitive protection in both the mycorrhizal and the nonmycorrhizal conditions. The effect of Ca2+ was an approximate fourfold increase in the respective Km values.
Alternatives for the no-observed-effect level
Authors: Hoekstra J.A. , van Ewijk P.H.
Published: March 2010

This paper questions the usefulness of the no-observed-effect level (NOEL) as a summary statistic for ecotoxicological experiments. Quantification of the NOEL depends critically on size and variability of an experiment: smaller and less precise experiments lead to higher values for the NOEL, which gives the wrong signal to suppliers of a NOEL. The NOEL will generally lie in a dose range where possible effects cannot be excluded, even within the context of the experiment. Hence it does not form a suitable starting point for extrapolation to field situations. Alternative methods of finding a dose with a negligible effect are discussed. A two-step procedure is proposed that involves finding the dose whose effect is at most 25%, followed by linear extrapolation to a dose whose effect is acceptably small. The procedure leads to higher values if efforts are made to increase the power of the experiment.