bluuebunny/crossref_metadata_2025 huggingface dataset:
No effects of a forest spraying of malathion on breeding blue tits (Parus caeruleus)
Authors: Pascual Juan Alberto
Published: March 2010

Ultra low volume (ULV) aerial spraying of the organophosphorus insecticide malathion is widely used in Spain to control Tortrix viridana, the most important lepidopteran pest of Spanish holm oak forests (Quercus ilex) A field study was carried out in spring 1988 to analyze the short term effects of a standard application rate of malathion (1,160 g a i /ha) on the breeding success of the blue tit (Parus caeruleus) Several blue tit reproductive parameters and seasonal variation of arthropod densities in canopy trees (focusing on caterpillars, the main food resource for breeding blue tits) were compared between a mal-athion-treated plot and a control plot None of the breeding parameters (nest abandonment, nest success, hatching success, nestling mortality, daily survival rate, and nestling weight) showed differences between the treated and the control plots Malathion spraying caused nearly a 100% mortality of the target pest Tortrix viridana, but it did not reduce availability of another Tortricidae (Archips xylosteana), with the result that food supply was similar or higher in the treated plot than in the control plot The main conclusion of this study is that a forest standard application of malathion did not cause adverse short-term effects on breeding blue tits Moreover, this work focused on the indirect effects of insecticides via food depletion, its results suggest that in these kinds of studies it is more important to assess the abundance of arthropods remaining alive after treatment than the degree of arthropod mortality caused by the insecticide
Effects of an oil production effluent on gametogenesis and gamete performance in the purple sea urchin (Strongylocentrotus purpuratus stimpson)
Authors: Krause Paul R.
Published: March 2010

Adult organisms subjected to chronic discharges from a point source of pollution may exhibit several sublethal responses. One such response is the impairment of gamete production. This may be expressed in the amount and/or quality of gametes produced by adults. In this study the effects of chronic exposure to produced water (an oil production effluent) on the gametogenesis and gamete performance of the purple sea urchin (Strongylocentrotus purpuratus Stimpson) were examined using an in situ caging experiment Adult purple sea urchins were kept in benthic cages arrayed down-field from a discharging dif-fuser at 13 sites, with distances ranging from 5 to 1,000 m. Cage exposures were maintained in the field for eight weeks, and each cage held 25 animals Gametogenesis was examined for each sex by comparing a size-independent measure of relative gonad mass as determined by analysis of covariance. Results showed that there was a significant negative relationship between these estimates of relative gonad mass and distance from the outfall for both sexes, indicating that sea urchins living closer to the outfall produced significantly larger gonads. Gamete performance was measured through a fertilization kinetics bioassay that held the concentration of eggs constant and varied the amount of sperm added The proportion of eggs fertilized under each sperm concentration was determined and the response fit to a model of fertilization kinetics This experiment showed significant differences in the fertilizabihty of eggs between cages, and egg fertilizabihty showed a positive relationship with distance away from the outfall These findings indicate that although adult sea urchins exposed to a produced water outfall exhibit larger gonads, they suffer a marked decrease in gamete performance
Bioassay-driven analysis of chewing tobacco extracts
Authors: Chou Chin C. , Hee Shane S. Que
Published: March 2010

The aims were to develop a method to simulate extraction of toxic components into human saliva, to identify these components through bioassay-driven analyses using the Microtox® test, and to quantify the toxic compounds. Chewing tobacco extractions into artificial saliva simulated oral chewing conditions. The Microtox bioassay-directed subfractionation scheme identified acutely toxic components in chewing tobacco extracts. GC-MS identified and quantified the toxic components. The subfractionation (pH 7 extraction, pH 2 extraction, then pH 10 extraction using organic solvents) scheme was shown to be comparable to biological digestive sequences and to simulate nicotine bioavailability. The low toxicity of artificial saliva allowed development of a sensitive bioassay. Nicotine was the major acutely toxic agent detected. Classification by Draize ocular irritative categories showed that leached nicotine concentrations were mildly to moderately irritating. Thus, the Microtox test can be used to detect irritative compounds and subfractions, and can be potentially applied to saliva biological monitoring in humans.
Community-level field method for testing the toxicity of contaminated sediments in estuaries
Authors: Watzin Mary C. , Roscigno Pasquale F. , Burke W. David
Published: March 2010

The objective of this study was to demonstrate a method for testing the toxicity of contaminated sediments under field conditions. An artificial sediment that matches field sediment in grain-size distribution and organic matter content was mixed from 11 components and used as the test substrate. Clean sediments and sediments spiked with zinc (∼8,000 mg/kg) were exposed in the field on a holding rack anchored on the bottom of Mobile Bay, Alabama. The abundance and diversity (species richness) of benthic invertebrate recruits were used as indicators of sediment quality. The number of recruits was significantly reduced by the presence of zinc in one-week exposures.
Modeling the accumulation of three waterborne chlorinated ethanes in fathead minnows (Pimephales promelas): A physiologically based approach
Authors: Lien Gregory J. , Nichols John W. , McKim James M. , Gallinat Carol A.
Published: March 2010

A physiologically based kinetic model was used to predict the accumulation of a homologous series of chlorinated ethanes in fathead minnows (Pimephales promelas). Uptake and accumulation of these compounds are described in terms of a few fundamental physiological, morphological, and physicochemical parameters. Chemical residues in 30-d-old fathead minnows exposed to 1,1,2,2-tetrachloroethane, pentachloroethane, and hexachloroethane were used to evaluate model performance. The predicted and observed accumulations of the chlorinated ethanes were in close agreement. A quantitative assessment of the major factors regulating the exchange of these compounds indicates that the cutaneous surface may be an important route of uptake in small fish.
Transgenic hsp 16-Lacz strains of the soil nematode caenorhabditis elegans as biological monitors of environmental stress
Authors: Stringham Eve G. , Candido E. Peter M.
Published: March 2010

Caenorhabditis elegans is a small, free-living hermaphroditic nematode that is widely used for the investigation of basic biological phenomena at the genetic and molecular levels. The hsp16 genes in this system encode a family of stress-inducible 16-kDa proteins. Stable transgenic nematode lines were derived that carry fusions of the hsp16 genes to the Escherichia coli lacZ reporter gene. These transgenic strains express high levels of β-galactosidase in the nucleus, in response to a heat shock or to a variety of chemical stressors. Agents tested to date that induce the stress response in these animals include Cd2+, Cu2+, Hg2+, Pb2+, Zn2+, AsO2−, and the herbicide paraquat. Some of these agents yield distinct tissue patterns of stress induction (e.g., Pb2+ in the posterior pharynx, Cd2+ throughout the pharynx, Hg2+ in intestine), suggesting that classification of stress agents in complex mixtures may be a useful feature of this biomonitoring system. Using a soluble β-galactosidase substrate, an assay was developed that allows the magnitude of the stress response to be measured. Stress reporter gene induction always occurred below the LC50 of the test substance, suggesting that this assay is a more sensitive and rapid indicator of stress than current LC50 assays using Caenorhabditis elegans.
Mitochondrial dna diversity of brown bullhead from contaminated and relatively pristine sites in the great lakes
Authors: Murdoch Mary H. , Hebert Paul D. N.
Published: March 2010

Brown bullhead were sampled from contaminated and relatively pristine sites to determine whether there was any association between genetic diversity and site contamination. Nine sites were sampled in the lower Great Lakes: five from Areas of Concern (identified by the International Joint Commission as having significant environmental degradation) and four from relatively clean areas of similar habitat type. Genetic variation was surveyed in the mitochondrial genome using restriction fragment length polymorphisms. Sixteen restriction enzymes were used to identify 42 distinct mitochondrial DNA haplotypes among 163 fish. Eight pairwise comparisons of populations at contaminated vs. clean sites showed that genetic diversity estimates were always lower in populations from contaminated sites. The most parsimonious explanation is that reduced diversity is a result of stochastic reductions in population size that have culled much of the genetic diversity from populations. Although contaminated sites support large populations of brown bullhead, historical environmental degradation at these sites may have reduced population size in the past, resulting in reduced present-day genetic diversity.
Actions and interactions of temperature, ph and photoperiod on mercury bioaccumulation by nymphs of the burrowing mayfly Hexagenia rigida, from the sediment contamination source
Authors: Odin M. , Feurtet-Mazel A. , Ribeyre F. , Boudou A.
Published: March 2010

Based on a three-compartment system — water, natural sediment, Hexagenia rigida nymphs — an experimental study was set up, using a complete factorial design, to quantify the actions and interactions of three abiotic factors (temperature: 10, 18, and 26°C; photoperiod: 6, 12, and 18 h per day; pH: 5.0 and 7.5) on inorganic mercury (HgCl2) and methylmercury (CH3HgCl) bioaccumulation by Hexagema rigida (whole organism and gills). The two chemical forms of the metal were initially introduced into the sediment; the exposure duration was 15 d. Total Hg burdens measured at the whole-organism level revealed a very high bioaccumulation capacity of this burrowing mayfly species and important differences between the two contamination conditions of the sediment source, a factor close to 20 observed in favor of methylmercury, for similar exposure conditions. Among the three abiotic factors taken into account, temperature and water-column pH played an important role on Hg bioaccumulated by the nymphs, when considered in isolation and in interaction. An increase in temperature from 10 to 26°C gave rise to an increase in Hg bioaccumulation, with the higher differences close to a factor of 1.7. On the other hand, acidification of the water column from 7.5 to 5.0 led to a decrease in the amounts of the metal accumulated by Hexagenia rigida. These effects were similar for the two Hg compounds, but they were more pronounced when the experimental units were contaminated by methylmercury. This comparative analysis of the amounts of metal bioaccumulated by whole organism and by the gills, estimates of nymph activity within the sediment, and results from earlier lab studies have generated several hypotheses on the involved mechanisms. We propose that ingested sediment is the predominant route of exposure and that the gut acts as a selective barrier that favors organic Hg absorption.
Comparison of whole-sediment, elutriate and pore-water exposures for use in assessing sediment-associated organic contaminants in bioassays
Authors: Harkey Gail A. , Landrum Peter F. , Klaine Stephen J.
Published: March 2010

Bioassays have frequently been used as tools to simulate exposure of benthos to sediment-associated contaminants in hazard assessments. Due to the problems involved with estimating bioavailability in whole-sediment bioassays, aqueous fractions such as elutriates and pore water have been substituted for whole-sediment exposures. The objective of this research was to compare and evaluate the bioavailability of representative neutral hydrophobic contaminants in whole sediments and in aqueous extracts of whole sediment (elutriate and pore water) in simultaneous bioassays, using three representative indicator species, Diporeia spp., Chironomus riparius larvae, and Lumbriculus variegatus. Aqueous extracts of whole sediment did not accurately represent the exposure observed in whole sediment. Generally, the aqueous extracts underexposed organisms compared to whole sediment, even after adjusting accumulation to the fraction of organic carbon in the test media. Accumulation comparisons among whole-sediment, elutriate, and pore-water exposures depended on sampling time. At some sampling times for some contaminants, differences in accumulation between a particular aqueous extract and whole sediment were not significant; however, these similarities were not observed for all species at the particular sampling time. Bioaccumulation and contaminant clearance data suggest that a number of factors such as the indicator species, exposure media, and chemical/physical properties of individual contaminants are responsible for the accumulation differences observed among the tested media. Normalizing bioaccumulation to the amount of organic carbon in a source compartment adjusted for bioavailability differences of only some contaminants. We suggest that the bioavailability of contaminants such as those tested cannot be accurately predicted in bioassays that expose organisms to aqueous representations of whole sediment.
Assessment of the toxic potential of PCB congener 81 (3,4,4′,5-tetrachlorobiphenyl) to fish in relation to other non-ortho-substituted pcb congeners
Authors: Harris G.E. , Kiparissis Y. , Metcalfe C.D.
Published: March 2010

PCB congener 81 (3,4,4′,5-tetrachlorobiphenyl) has been detected in fish tissues from various sites in North America. The embryotoxicity of this compound to medaka (Oryzias latipes) and the induction of hepatic aryl hydrocarbon hydroxylase (AHH) in rainbow trout (Oncorhynchus mykiss) were determined to assess the toxic potency of this compound relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and two other non-ortho-substituted PCB compounds, congener 77 (3,3′,4,4′-tetrachlorobiphenyl) and congener 126 (3,3′,4,4′,5-pentachlorobiphenyl). The TCDD toxic equivalency factors (TEFs) estimated for congener 81 from two end points in the medaka embryotoxicity assay were 0.0014 (from mortality data) and 0.006 (from swim bladder inflation data). The TEF estimated for congener 81 from data on AHH induction in rainbow trout was 0.004. All TEFs were greater than those estimated for congener 77 but were less than the TEFs estimated for congener 126. On the basis of these toxicity data, it is suggested that this congener may contribute significantly to the toxic burden of planar halogenated aromatic hydrocarbons in fish.
Toxicokinetics and toxicity of sediment-associated pyrene to lumbriculus variegatus (oligochaeta)
Authors: Kukkonen Jussi , Landrum Peter F.
Published: March 2010

The oligochaete Lumbriculus variegatus has been proposed for whole-sediment bioassays to assess sediment contamination. Our work examines Lumbriculus variegatus exposure to pyrene-dosed Lake Michigan sediment at 0.4 ng g−1 and 64, 132, 206, and 269 μg g−1. Both bioaccumulation and survival were followed to enhance Lumbriculus variegatus development as a bioassay organism. Lumbriculus variegatus accumulated sediment-associated pyrene rapidly and achieved apparent steady state within 48 to 168 h. The pyrene uptake clearances (ks, g sed g−1 animal h−1) ranged from 0.039 to 0.132 and decreased with increasing pyrene concentration. At high pyrene concentrations, the worms avoided the sediment, which reduced accumulation and likely minimized the mortality response. In addition, the effect of organism loading on bioaccumulation was determined at different animal densities, 1:10, 1:50, and 1:100 g dry weight Lumbriculus variegatus:g sediment organic carbon, and a sediment pyrene concentration of 0.4 ng g−1. Surprisingly, the bioaccumulation declined as organism density decreased. Pyrene elimination was rapid in clean sediment (ke = 0.026 ± 0.002 h−1) but was much slower in water (ke = 0.0043 ± 0.0007 h−1). Bioavailability apparently declined for exposures in sediment stored 1.5 months, based on the estimate of ke from nonlinear regression compared to direct measures of elimination. The apparent decline was attributed to both a decline in lipid content during the experiment and changes in pyrene bioavailability. Finally, for bioaccumulation studies, gut purging at a set time (e.g., 24 h) may result in an underestimate of contaminant concentration in organisms. An elimination study with extrapolation to the initial body burden can ensure that biases due to incomplete elimination of gut contents and body burden losses during the purging process are minimized.
Exposure of fish to biologically treated bleached-kraft effluent. 2. Induction of hepatic cytochrome P4501A in mountain whitefish (Prosopium williamsoni) and other species
Authors: Kloepper-Sams P.J. , Benton E.
Published: March 2010

Induction of the hepatic detoxification enzyme cytochrome P4501A has been observed in fish exposed to bleached-kraft mill effluents (BKME). P4501A content was examined in three species of wild fish exposed to BKME in a western Canadian river as part of an extensive program that included chemical monitoring, fish population studies, and other fish biochemical and physiological measurements. The Rocky Mountain whitefish Prosopium williamsoni exhibited marked induction of P4501A compared to reference whitefish, as measured by both catalytic activity and immunoreactive protein content. Similar P4501A induction was observed 4 d after reference fish were treated with 20 mg/kg β-naphthoflavone. Whitefish P4501A levels have declined from a peak in spring 1991, following mill process modifications and concurrent with reductions in body burdens of hydrophobic compounds. Whitefish collected near the mill, moved upstream of effluent discharges, and held for 8 d showed no significant loss of hepatic P4501A-related (ethoxyresorufin O-deethylase, EROD) enzyme activity or P4501A protein levels. For spring 1991, correlations were found between EROD activity and measures of chronic exposure to BKME (e.g., muscle 2,3,7,8-tetrachlorodibenzo-p-dioxin content), but not between EROD and measures of acute exposure (e.g., bile content of resin acids or chlorophenolic metabolites). These and other lines of evidence indicate that the P4501A-inducing agent(s) at this site may be neither waterborne nor rapidly eliminated. A second species, longnose sucker (Catostomus catostomus), collected near the mill exhibited modest (two- to threefold) P4501A induction. For both species, no significant correlations between P4501A induction and trends in other biological responses were found, as described in a companion paper. Burbot (Lota lota) had hepatic EROD activities generally in the range of reference values, despite substantial exposure to mill-related compounds. In contrast to studies at historically degraded pulp mill sites, P4501A induction is the only major biological response observed to date at this site. As P4501A induction is not related to adverse effects, it could be best classified as an indicator of exposure to BKME.
Exposure of fish to biologically treated bleached-kraft mill effluent. 3. Fish habitat and population assessment
Authors: Swanson S.M. , Schryer R. , Shelast R. , Kloepper-Sams P.J. , Owens J.W.
Published: March 2010

Populations of mountain whitefish (Prosopium williamsoni) and longnose sucker (Catostomus catostomus) exposed to bleached-kraft mill effluent (BKME) in the Wapiti/Smoky river system in northwestern Alberta were compared to similar populations in a reference river system (the upper North Saskatchewan River). Fish species distribution and relative abundance patterns were linked to natural events such as floods and low flows, and to habitat quality. There was no evidence that fish were avoiding the effluent plume area; relative abundance was often highest near the effluent discharge due to use of this area for overwintering and rearing. Radiotelemetry and recapture studies indicated that fish movements could be both rapid and extensive, occurring during spawning periods and at other times of the year. Thus, exposure could not be assumed to be related to capture location alone; separate exposure measures were necessary. Populations of exposed mountain whitefish and longnose sucker were growing and reproducing successfully. Higher condition factors in exposed longnose suckers and greater mesenteric fat stores in exposed individuals of both species were not accompanied by any apparent disruption in allocation of energy to reproduction or growth. The age structure of the populations showed that there had been no losses of age classes through reproductive or recruitment failures, and growth curves were indistinguishable from reference curves. There were no correlations between indicators of exposure and population-level effects. Important natural phenomena, including a one-hundred-year flood and natural upstream/downstream habitat gradients, affected species distribution and were correlated with some population parameters such as condition factors and relative gonad size.
Use of life tables and lc50 tests to evaluate chronic and acute toxicity effects of copper on the marine copepod tisbe furcata (baird)
Authors: Bechmann Renée Katrin
Published: March 2010

Cohorts of the epiphytic marine copepod Tisbe furcata were chronically exposed to copper in life-table experiments to test whether ecologically relevant impacts can occur at sublethal concentrations. Data on fecundity, longevity, and rate of development were used to calculate rm – the intrinsic rate of natural increase. Acute toxicity tests (96-h LC50 tests) were done to compare the concentrations of copper affecting individual lethality and population biology. The LC50 value for Tisbe furcata nauplii was 2.8 μM copper (178 μg/L). The results from the life-table experiments show that 0.9 μM copper (32% of LC50) can cause significant negative effects on demographic parameters (total production of nauplii, life span, and reproductive period for fertile females) and reduce the percentage of fertile females leading to a 61% reduction of rm. However, rm was still positive at 0.9 μM copper, and the net reproductive rate (Ro) indicated a fivefold increase in population size from one generation to the next. Although there were no significant effects of copper at 0.5 μM (18% of LC50), there was a negative trend in almost all the demographic parameters, indicating that the observed 10% reduction of rm at this concentration was an effect of copper. For the substances tested so far with both acute LC50 tests and life-table experiments, rm was not reduced at concentrations below LC50/10. When life-table experiments are used as part of environmental hazard assessments, concentrations below LC50/10 should be tested to detect substances that are potentially harmful to the environment at sublethal concentrations, rather than testing concentrations close to LC50.
Adsorption and desorption hysteresis of pahs in surface sediment
Authors: Fu Gongmin , Kan Amy T. , Tomson Mason
Published: March 2010

The overall objective of this research is to investigate the desorption reversibility of two PAHs (naphthalene and phenanthrene) from sediment materials Batch adsorption and desorption experiments were designed to minimize the contribution of experimental artifacts The sorbent was sediment obtained from Johnson Ranch (Lula, OK) that contained 92% sand, 6% silt, 2% clay, and 0 27% organic matter Batch adsorption and desorption experiments with radiolabeled chemicals were conducted at various pH levels and ionic strengths, solute concentrations ranging over several orders of magnitude, and equilibrium times up to five months These model pollutants appear to be readily adsorbed by sediment, but a portion of the bound pollutants resists desorption The adsorption is rapid and predictable using published Koc and Kow relationships From 30 to 50% of the adsorbed amount resists desorption The resistant fraction can be desorbed in water only at rates one to three orders of magnitude slower than previous observations or theories It is hypothesized that some multistep chemical or mechanical effects promote soil aggregation and/or entrapment of pollutants in the soil organic matter during adsorption
Production of a novel recombinant cell line for use as a bioassay system for detection of 2,3,7,8-tetrachlorodibenzo-P-dioxin-like chemicals
Authors: El-Fouly M.H. , Richter C. , Giesy J.P. , Denison M.S.
Published: March 2010

Exposure to specific halogenated aromatic hydrocarbons (HAHs), such as 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), can produce a wide variety of species- and tissue specific toxic and biological effects The presence of HAHs in environmental samples as complex mixtures has made it difficult to predict the biological and toxic potency of these chemicals We have used aspects of the molecular mechanism of action of these chemicals to develop a species-specific bioassay system for detection of bioactive HAHs in complex mixtures Here we describe construction and utilization of a recombinant expression vector that responds to these HAHs with the induction of an easily measurable gene product, heat-stable human placental alkaline phosphatase (PAP) This vector contains the PAP gene under TCDD-inducible control of four dioxin-responsive DNA enhancer elements HAH inducible expression of PAP from the recombinant vector occurs in a dose- and Ah-receptor- (AhR-) dependent manner Stable transfection of this vector into mouse hepatoma cells has produced a novel cell line in which AhR-dependent induction of gene expression can easily be measured This transfected cell line can readily be used for detection and relative quantitation of AhR agonists in complex mixtures of environmental and biological samples and for identification and characterization of novel AhR agonists
Effects of pre- and postnatal exposure to 3,3′,4,4′,5-pentachlorobiphenyl on physical development, neurobehavior and xenobiotic metabolizing enzymes in rats
Authors: Bernhoft A. , Nafstad I. , Engen P. , Skaare J.U.
Published: March 2010

An experiment was conducted to study the effects of the coplanar non-ortho-chlorinated congener 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) in rats exposed during fetal development and postnatal suckling period. Two groups of eight dams were administered by gavage six doses of 10 and 20 μg/kg body weight of PCB-126 dissolved in corn oil every second day from days 9 to 19 of gestation. The corresponding control rats were treated with corn oil only. The physical development of the offspring was observed. From age 5 to 18 weeks, 12 randomly selected pups from each group were tested daily for visual discrimination with successively more demanding tasks in Skinner boxes. The effects of PCB-126 on hepatic xenobiotic metabolizing enzyme activities and the concentrations of PCB in the liver and brain were investigated in samples from pups of different age and from their mothers. The litter size, the body weights, and the survival of the exposed sucklings were reduced, and the onset of spontaneous movement and neuromuscular maturation were delayed, whereas the development of reflexes was not affected, as compared to controls The body weight was still reduced in a dose-related manner up to 18 weeks postpartum. Also, the postpartum body weight of the PCB-exposed mothers was reduced as compared to controls, but the difference disappeared at weaning. The hepatic enzyme activities of cytochrome P450 1A1 examined by ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST) toward 1-chloro-2,4-dinitrobenzene (CDNB) were increased in both the exposed pups and their mothers, and the relative liver weight was increased in the exposed pups. The behavior training in Skinner boxes did not reveal PCB effects on the learning performance or the activity level Hepatic PCB-126 residues were detected in samples collected throughout the experiment, whereas no detectable concentration was found in the brain We conclude that exposure of this PCB congener in utero and through lactation showed fetotoxic effects, delayed physical maturation, and induced liver xenobiotic metabolizing enzymes without causing neurobehavioral effects
Interspecies toxicity correlations of rat, mouse and Photobacterium phosphoreum
Authors: Kaiser Klaus L. E. , McKinnon Mark B. , Fort Farrel L.
Published: March 2010

This study investigates quantitatively the interspecies relationships of the acute toxicity of 684 organic chemicals to the rat, the mouse, and the luminescent marine bacterium Photobacterium phosphoreum, commonly known as the Microtox® test The results indicate significant relationships between the Microtox EC50 and rat and mouse LD50 values The goodness of fit increases strongly from the oral to the intraperitoneal to the intravenous route of administration for each of the mouse and rat Standard errors of the estimated rat values range from 0 52 to 0 72 log units of toxicity (after and before outlier removal, respectively) over a toxicity range of 4 6 (intraperitoneal) to 5 0 (oral) log units (mmol/kg body weight) of toxicity For each of the three routes of administration, rat and mouse data are also highly correlated This allows the computation of rat toxicities from mouse data and vice versa with standard errors of the estimates of 0 28 (intraperitoneal) to 0 30 (oral) log units
Biological alternatives to chemical identification for the ecotoxicological assessment of industrial effluents: The RTG-2 in vitro cytotoxicity test
Authors: Castaño Argelia , Vega Milagros , Blazquez Teresa , Tarazona Jose V.
Published: March 2010

Ecotoxicology is concerned with the effects of chemicals on biological systems Identifying components of complex aqueous effluents poses special problems, and can be useless if there is a lack of information on the biological effects of the identified chemicals Toxicity-based (bioassay directed) sample fractionation can be very useful, but the small amount of fractioned material is a constraint that can be solved by using in vitro tests The RTG 2 in vitro cytotoxicity test has been used to assess (a) the efficacy of a treatment plant in the aeronautics industry and (b) the exposure of fish and molluses cultured in Esteiro Bay to the effluent of a fish processing factory Ecotoxicological assessments could be done without identifying the responsible chemicals The RTG-2 test was used in combination with concentration/fractionation procedures It proved that the toxicity of the liquid wastes from the aeronautics industry was eliminated by the treatment, and that molluses and fish reared in Esteiro Bay had accumulated toxic chemicals dumped by the fish-processing factory A combination of the RTG-2 cytotoxicity test and HPLC proved to give useful information even for chemicals not identified by GC MS
Fetax interlaboratory validation study: Phase II testing
Authors: Gaudet-Hull Angela M. , Rayburn James R. , Bantle John A. , Burton Dennis T. , Turley Steven D. , Dawson Douglas A. , Dumont James N. , Finch Robert A. , Maurice Margaret A. , Fort Douglas J. , Linder Greg , Buchwalter David
Published: March 2010

The Frog Embryo Teratogenesis Assay—Xenopus (FETAX) is a 96 h whole embryo developmental toxicity screening assay that can be used in ecotoxicology and in detecting mammalian developmental toxicants when an in vitro metabolic activation system is employed A standardized American Society for Testing and Materials (ASTM) guide for the conduct of FETAX has been published along with a companion atlas that helps in embryo staging and identifying malformations As part of the ASTM process, an interlaboratory validation study was undertaken to evaluate the repeatability and reliability of FE TAX Six different laboratories participated in the study Each laboratory utilized one technician with the exception of one laboratory, which utilized two independent technicians In Phase I, FETAX proved to be more repeatable and reliable than many other bioassays However, some excessive variation was observed in a few laboratories Some of this variation may have been due to an initial lack of experience with the assay by some technicians Phase II, which is reported here, showed far less intralaboratory and interlaboratory variability than did Phase I Nonteratogens such as saccharin and sodium cyclamate showed the most consistent results, whereas more variability was observed for the teratogens caffeine and 5-fluorouracil Interlaboratory coefficient of variation values for all FETAX end points ranged from 7 3 to 54 7% The minimum concentration to inhibit growth proved to be the most variable end point for three of the four test chemicals, whereas the LC50 and EC50 (malformation) proved to be less variable
Excretion of cadmium and zinc during moulting in the grasshopper Omocestus viridulus (orthoptera)
Authors: Lindqvist Lars , Block Mats
Published: March 2010

Nymphs of Omocestus viridulus (Orthoptera) were reared on grass leaves containing known amounts of 109Cd or 65Zn. After the animals moulted to adults, contents of these metals were measured in the grasshoppers, in the cast of exuviae and in the feces produced during rearing. Dry weights of adult bodies and exuviae were lower for 109Cd-treated grasshoppers than for those given 65Zn. Exuviae accounted for only a minor part of the excreted 109Cd and 65Zn. The 109Cd was assimilated from food to a much smaller extent than was 65Zn. After 15 d of rearing, −50% of the ingested 65Zn, but only 10% of the ingested 109Cd, remained in the grasshoppers. Because the amount of 109Cd in the grasshopper nymphs decreased with time, whereas that of the exuviae were constant, content in exuviae constituted a larger portion of the total content of 109Cd with increasing time between feeding of 109Cd and moulting. For 65Zn there was no such trend.
Application of canonical variate analysis in the evaluation and presentation of multivariate biological response data
Authors: Adams S. Marshall , Ham Kenneth D. , Beauchamp John J.
Published: March 2010

We have applied canonical variate analysis procedures for evaluating multivariate responses of fish populations to various contaminant stressors. Using examples of fish populations experiencing high levels of PCBs in a reservoir and mixed contaminants in a stream, the significance of integrated stress responses among sample populations was compared statistically and graphically using two- and three-dimensional data presentations. For fish from both systems, the most powerful axis of discrimination among sample populations was correlated with the activity of the detoxification enzyme, EROD (7-ethoxyresorufin O-deethylase). Indicators of organ dysfunction were the variables most correlated with the second axis of discrimination among sites in the PCB-contaminated reservoir study. Indicators of lipid metabolism were the variables most correlated with the second and third axes of discrimination among stream fish. Canonical variate analysis procedures are useful for evaluating multivariate response data because they take into account the interrelations and associations among response variables and reveal the integrated nature of organism responses to stress. Using this procedure, the significance of integrated stress responses among different sample populations can be graphically compared and evaluated using two- or three-dimensional data presentations. These types of graphical displays help provide an understanding of the relationships among sample populations that may not be evident from tabular or other types of data summaries. In addition, this approach can be useful in helping to identify factors such as toxicants or other environmental stressors which impair the health of aquatic ecosystems.
New qsar models for polyhalogenated aromatics
Authors: Nevalainen Tapio , Kolehmainen Erkki
Published: March 2010

Electronic properties of polychlorinated dibenzo p dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polychlorinated diphenyl ethers (PCDEs) were calculated using the semi-empirical AM1 method The calculated electronic descriptors — the energy of the lowest unoccupied molecular orbital (ELUMO), the energy of the highest occupied molecular orbital (EHOMO), the ELUMO-EHOMO gap (dE), and molecular polarizability — are related to the Ah receptor binding affinity values of PCDDs, PCDFs, and PCBs and immunotoxicity values for PCDEs The quantitative structure activity relationships (QSARs) based on chlorine substitution patterns were also constructed, and they proved to be very predictive for Ah receptor binding Significant correlations of the electronic factors were found between the dE and Ah receptor binding affinities for PCDDs, PCDFs, and PCBs and for immunotoxicity of PCDEs A combination of descriptors ELUMO and the total number of chlorine atoms attached to a molecule (nCl) gives significant correlation for the Ah receptor binding of PCDFs and for immunotoxicity of PCDEs Hydrophobicity values taken from the literature were shown to be non-significant for toxicity prediction of these polychlorinated compounds
A life-cycle inventory of baby diapers subject to Canadian conditions
Authors: Vizcarra A.T. , Lo K.V. , Liao P.H.
Published: March 2010

A life-cycle inventory of cloth and disposable diapers was conducted based on diapering habits in Canada The parameters evaluated were energy consumption, water consumption, raw materials consumption, atmospheric emissions, water-borne wastes, and solid wastes The results showed that cloth diapers consume more water and produce more waterborne wastes than do disposable diapers, whereas disposable diapers consume more raw materials and produce more solid wastes than do cloth diapers Sensitivity analyses proved these differences to be significant However, with respect to energy consumption and atmospheric emissions, the computed differences were assessed to be insignificant inasmuch as these may be offset by reasonable variations in cloth to-disposable diaper usage ratio, market sharing between home laundering and service laundering, number of laundry loads per week, laundry water temperatures, percentage of dryer drying and line drying, and drying time The Canadian inventory results were compared to those of three similar U S diaper life cycle inventories Although they differ numerically on the estimated rates of resource consumption and environmental releases, all the studies agree that cloth diapers consume more water and produce more waterborne wastes, whereas disposable diapers consume more raw materials and produce more solid wastes, their findings concerning energy consumption and atmospheric emissions were not as consistent The study concludes that neither diaper system can be considered absolutely superior environmentally
Toxicokinetics and toxicity of sediment-associated pyrene and phenanthrene in Diporeia spp.: Examination of equilibrium-partitioning theory and residue-based effects for assessing hazard
Authors: Landrum Peter F. , Dupuis Wendy S. , Kukkonen Jussi
Published: March 2010

The amphipod Diporeia spp. was exposed to pyrene(0.14 to 1.11 μmol g−1) or phenanthrene (0.08 to 0.62 μmol g−1)-dosed sediments for month-long exposures. Phenanthrene was only slightly toxic with 12±3% mortality at the highest sediment dose (0.62 μmol g−1). Failure to attain and maintain toxic residue body burdens, based on a nonpolar narcosis concentration of approximately 6 μmol g−1, accounts for the low mortality. Phenanthrene toxicokinetic parameters were essentially constant among all doses and consistent with previous measures. Sediment concentration was a poor representation of dose for mortality by pyrene. The relative pyrene distribution among the <63-μm particles increased in the smallest-sized particles at larger doses. An apparent stimulation of pyrene accumulation was observed as a peak in uptake clearance values between sediment concentrations of 0.16 and 0.26 μmol g−1 dry sediment. (Uptake clearance is the amount of source scavenged of contaminant per mass of organism per time.) The pyrene particle-size distribution and the variation in kinetics with dose provide a partial explanation for the poor representation of dose by the sediment concentration. The pyrene body burdens provided a good dose response yielding LD50 values of 6.3 (4.6–41.7, 95% C.I.) and 9.4 (7.9–54.2) μmol g−1 for two experiments. These values are consistent with the residue concentrations for 50% mortality by a nonpolar narcosis mechanism. Comparing the experimental and predicted equilibrium partitioning-based sediment concentrations for 50% mortality, the equilibrium prediction overestimates the toxic pyrene sediment concentration by approximately a factor of ten. Diporeia behavior, differential particle-size distribution, and kinetic limitations appear as likely reasons for the variation between calculated and observed concentrations required to produce mortality.
Lethal body concentrations and accumulation patterns determine time-dependent toxicity of cadmium in soil arthropods
Authors: Crommentuijn Trudie , Doodeman Connie J A M. , Doornekamp Anja , Van Der Pol Joost J. C. , Van Gestel Cornelis A. M , Bedaux Jacques J. M.
Published: March 2010

Time-dependent toxicity in bioassays is usually explained in terms of uptake and elimination kinetics of the toxicant By comparing different species with essentially different accumulation kinetics, a firm test of this concept may be made This article compares the sensitivity of six soil arthropods, the collembolans Orchesella cincta and Tomocerus minor, the oribatid mite Platynothrus peltifer, the isopods Porcellio scaber and Oniscus asellus, and the diplopod Cylindroiulus britannicus, when exposed to cadmium in the food Survival was determined at various time intervals, accumulation of cadmium in the animals was measured at one time interval Kinetic based toxicity models were fitted to the data, and estimates were obtained for lethal body concentration, uptake rate constant, elimination rate constant, and ultimate LC50 Two different accumulation patterns could be discerned, these were correlated with time-survival relationships One, species that have the possibility to eliminate cadmium will reach an equilibrium for the internal concentration and also an ultimate LC50 Two, species that are unable to eliminate cadmium but store it in the body will have an ultimate LC50 equal to zero For these species the time in which the lethal body concentration is reached is more important Taxonomically related species appeared to have comparable accumulation patterns, but lethal body concentrations differed It is concluded that knowledge of the accumulation pattern is indispensable for the evaluation of species' sensitivities to toxicants
Accumulation of polychlorinated biphenyl congeners from lake champlain sediments by Mysis relicta
Authors: Lester Deborah C. , McIntosh Alan
Published: March 2010

Polychlorinated biphenyl (PCB) levels in lake trout (Salvelinus namaycush) from Lake Champlain often exceed the F.D.A. “tolerance level” of 2 μg/g (wet weight). Of added concern are recent studies that suggest a relationship between the dioxin-like properties of non-ortho-substituted PCB congeners and impaired lake trout egg hatchability. Dietary accumulation of PCBs is thought to be an important exposure route for fish. The epibenthic freshwater shrimp Mysis relicta is an integral part of the benthic and pelagic food web in Lake Champlain and may act as a link between PCBs in sediments and lake trout. Previous investigations have shown that diurnal migrations of mysids enhance the movement and distribution of toxic contaminants, effectively coupling the benthic and pelagic zones. The objective of this research was to examine the role contaminated sediments play in the transfer of PCBs to mysids. Bioaccumulation was assessed by exposing mysids to such sediments in two ways: (a) with organisms screened from sediments; and (b) with organisms in direct contact with sediments. Accumulation of PCBs over the course of the 24-day exposure period was examined on the following days: 0, 3, 6, 12, 21, and 24. Eighty-nine individual PCB congeners were measured in tissue and sediment. Mysids in direct contact with sediments accumulated significantly higher levels of PCBs than did organisms screened from sediments. Mysids accumulated substantial levels of PCBs, suggesting they may play an important part in the transfer of PCBs from sediments into the Lake Champlain food web. It is clear from this research that sediments can play a critical role in the accumulation of PCBs by mysids.
Inhibition of acetylcholinesterase in the australian freshwater shrimp (Paratya australiensis) by profenofos
Authors: Abdullah A.R. , Kumar A. , Chapman J.C.
Published: March 2010

Profenofos induced significant inhibitory effects on the AChE activity of Paratya australiensis ranging from >40% inhibition at sublethal concentrations of 0.1 to 1.0 μg/L to >80% inhibition at lethal concentrations of ≥10 μg/L. Sublethal chronic exposure (21 d) at a concentration of 0.15 μg/L caused persistent reduction in AChE activity of up to 60%, whereas recovery of AChE activity to normal levels from a 24-h exposure to 0.1 μg/L profenofos required less than 9 d. Shrimp were exposed to 0.1 μg/L profenofos for 24 h and then allowed a period of recovery in pesticide-free water; at the end of this treatment the AChE activity of affected shrimp approached control level. Subsequent 24-h exposures with intermittent stay in pesticide-free water for the same duration as the initial recovery phase resulted in greater inhibition in AChE activity as compared to the initial 24-h exposure. Furthermore, the AChE activity of shrimp at the end of the recovery phases remained significantly depressed.
Ecological assessment for the wetlands at milltown reservoir, missoula, montana: Characterization of emergent and upland habitats
Authors: Linder Greg , Hazelwood Robert , Palawski Don , Malloy John , Dubois Kristi , Bollman Michael , Wilborn David , Ott Suean , Pascoe Gary , Dalsoglio Julie
Published: March 2010

Wetlands in mining districts in the western United States are frequently impacted by heavy metal contaminated sediments The present study summarizes a soil contamination evaluation and an ecological assessment completed for a Superfund site located at Milltown Reservoir wetlands (MRW) in western Montana For wetlands, as well as upland habitats adjacent to wetlands, biological evaluations in the field and laboratory should be considered critical components in the ecological risk assessment process Depending upon habitat type, field and laboratory methods have been developed for hazard and risk assessment that lend themselves directly to the Superfund ecological risk assessment process, and that consider contaminant bioavailability and subtle expressions of adverse biological effects associated with chronic exposures As part of an ecological risk assessment for MRW, field surveys and a variety of biological test methods (e g., terrestrial and aquatic tests) were critical to the wetland evaluation For evaluating heavy metal effects at MRW, field and laboratory methods within the ecological assessment included wetlands delineation and preliminary plant and wildlife survey, vegetation tests in emergent and upland habitats, soil macroinvertebrate (earthworm) tests, preliminary studies using amphibian and bacterial test systems, soil characterizations, and chemical analysis of soils, sediments, and biological materials In conjunction with chemical analyses, these biological and ecological evaluations yielded an integrated evaluation of ecological effects and exposure at MRW The data gathered from laboratory and field work at MRW suggested that biological and ecological effects were subtle in their expression in the wetland In conjunction with sediment contamination evaluations, these studies should reduce the uncertainty associated with the baseline ecological risk assessment for MRW