bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cryoalgotox: Use of cryopreserved alga in a semistatic microplate test
Authors: Benhra Ali , Radetski Claudemir Marcos , Férard Jean-François 
Published: March 2010

AbstractUse of cryopreserved alga Selenastrum capricornutum has been evaluated as a simple and cost-efficient procedure in a new semistatic algal ecotoxicity test. Experiments have been conducted to compare performance criteria of this method, named Cryoalgotox, versus the classic microplate test using fresh algae. Cryoalgotox 72-h 50% effective concentrations (EC50s) determined with Cd2+, Cu2+, Cr6+, and atrazine were more sensitive, repeatable (low coefficients of variation), and reproducible (low time effect) than the results obtained with the classical microplate tests. The effect of storage time at −80°C on the sensitivity of the algae was assessed using cadmium as a toxic reference; it was shown that algae stored at −80°C over a 3-month period gave comparable toxicity results to those found with fresh algae.
Evaluation of the water-effect ratio procedure for metals in a riverine system
Authors: Diamond Jerome M , Koplish Daniel E , McMahon Joe , Rost Robert 
Published: March 2010

Abstract
Site-specific metal standards were determined for a part of the lower Lehigh River using the U.S. Environmental Protection Agency's water-effect ratio (WER) procedure. The WERs were based on laboratory and site water (collected downstream of the City of Allentown Publicly Owned Treatment Works) testing of the species Ceriodaphnia dubia and Pimephales promelas (fathead minnow) and five metals (copper, cadmium, lead, silver, and zinc) during four different months. Both species generally exhibited similar patterns in WERs. The greatest variability between the two species was observed for copper, silver, and lead. Ceriodaphnia yielded a lower mean WER than the fathead minnow for lead and zinc and WERs similar to those of the fathead minnow for copper, cadmium, and silver. The species more sensitive to a given metal did not always exhibit a higher WER, as had been previously assumed. A comparison of final WER calculations indicated that the geometric mean WER (1983 method) was typically higher than the final WER obtained using the 1994 guidance. For most metals, site water toxicity was reduced due to nonacutely toxic dissolved metal. Copper yielded the highest final WER regardless of the calculation method used. Regression analyses indicated that the copper WER was directly related, and the cadmium WER inversely related, to effluent concentration. Copper, lead, and silver WERs were related to site water pH. Cadmium and lead WERs were related to pH and dissolved solids. Zinc WERs were unrelated to any of the water quality variables measured and were similar among site water samples. Our results suggest it is prudent to use two species in WER testing and different site water samples to derive a final WER, particularly at sites that are not effluent dominated.
Evaluation of prairie grass species as bioindicators of halogenated aromatics in soil
Authors: Siciliano Steven D , Germida James J , Headley John V 
Published: March 2010

Abstract
The purpose of this study was to assess the potential of prairie grasses as bioindicators of toxicants in soil and to investigate the effect different soil types and organisms have upon the germination of plant bioindicators. As a model compound, we used 2-chlorobenzoic acid (2CBA), a hydrophilic, polar compound present in the degradation pathways of halogenated aromatics. The germination response of prairie grasses to Aroclor™ 1260-contaminated soil, with concentrations ranging from 13 to 133 μg kg−1 total polychlorinated biphenyls, was also investigated. The grasses responded to a wide range of contamination levels, with a 12- and 10-fold difference in the sensitivity of grass species to 2CBA and Aroclor, respectively. Canada blue grass (Poa compressa) and slender wheatgrass (Agropyron trachycaulum) were selected for further study of the effects of soil type and biological treatments on bioindicator response to 2CBA. Canada blue grass response in three of four soils was characterized by Y = 110 — 26 × ln(X), while in the fourth soil it was Y = 94 — 1.6 × X, where Y equals percent germination and × the 2CBA concentration. Slender wheatgrass response was Y = 140 — 23 × ln(X), with no significant difference between soil types. Previous biological treatments of soil significantly affected the response of slender wheatgrass as a bioindicator. Growing plants or plants inoculated with bacteria in noncontaminated soil before slender wheatgrass was planted inhibited emergence, changing the logarithmic relationship between germination and 2CBA concentrations to Y = 100 — 0.28 × X. Prairie grasses are potentially useful bioindicators of chlorinated aromatics in soil, but biological interactions may alter the bioindicator response.
Estrogenic activity in five United Kingdom rivers detected by measurement of vitellogenesis in caged male trout
Authors: Harries Jule E , Sheahan David A , Jobling Susan , Matthiessen Peter , Neall Paula , Sumpter John P , Tylor Tina , Zaman Nicholas 
Published: March 2010

Abstract
It was recently demonstrated that most, if not all, effluents of sewage-treatment works (STWs) in the United Kingdom are estrogenic to fish. As many STWs discharge into rivers, it is possible that some stretches of rivers downstream of where the effluent enters might also be estrogenic. To assess this possibility, the induction of vitellogenin synthesis in caged male trout placed at various distances downstream of the effluent entry point was used as a biomarker of estrogen exposure. Individual discharges into five rivers in England were studied. In four cases, fish placed in the neat effluent, or close to where it entered a river, showed very marked and rapid increases in their plasma vitellogenin concentrations, demonstrating that the effluent was estrogenic. In two of these four cases, none of the downstream sites were estrogenic, whereas in one of the four, fish placed at a site 1.5 km downstream did respond by synthesizing appreciable amounts of vitellogenin, although sites further downstream were not estrogenic. The situation in the fourth river was quite different; not only was the effluent extremely estrogenic (a maximum vitellogenin response in the mg/ml range was attained), but so were all the other study sites on the river, the last of which was 5 km downstream of where the effluent entered. This particular river receives trade effluent from wool-scouring mills, which contains much higher concentrations of alkylphenolic chemicals than any of the other discharges studied. It is suggested that these chemicals probably account for the estrogenic activity of this river. The final (fifth) river showed no estrogenic activity, not even in the neat effluent. This discharge comes from a very small STW, which receives no trade waste, and one or both of these factors may account for why the effluent (and hence the river) was not estrogenic.
An in vitro rainbow trout cell bioassay for aryl hydrocarbon receptor-mediated toxins
Authors: Richter Catherine A , Tieber Virginia L , Denison Michael S , Giesy John P 
Published: March 2010

Abstract
Halogenated aromatic hydrocarbons (HAHs) and other chemicals that act as aryl hydrocarbon (Ah) receptor (AhR) agonists cause a variety of toxic effects. In sac fry of many fish species, these effects include blue-sac disease and mortality. Because HAHs occur in complex mixtures, their toxicity in the environment is difficult to predict. A bioassay useful in predicting AhR-mediated toxicity to fish was developed using the RTH-149 rainbow trout hepatoma cell line. Stable transfection of this cell line with the pGudLuc1.1 plasmid, which contains a firefly luciferase reporter gene under the transcriptional regulation of dioxin responsive enhancers, has produced a recombinant cell line designated Remodulated Lightning Trout (RLT 2.0). The RLT 2.0 bioassay method detection limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is 4 pM. The responses of the RLT 2.0 bioassay to TCDD and several HAH congeners closely matched the responses observed in vivo in fish. The RLT 2.0 bioassay can provide an integrative measure of the total AhR-mediated toxic activity of complex mixtures to fish. The assay will be useful in screening environmental extracts, guiding chemical analysis, and interpreting the AhR-mediated mechanism of toxicity.
Identification of acute toxicants in new bedford harbor sediments
Authors: Ho Kay T , McKinney Richard A , Kuhn Anne , Pelletier Marguerite C , Burgess Robert M 
Published: March 2010

Abstract
New Bedford Harbor (NBH) is a marine Superfund site contaminated with high concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and metals. Experiments were conducted to determine the causal toxic agent(s) in pore waters from New Bedford Harbor sediments to amphipods and mysid shrimp. Chemical manipulations to characterize toxicity revealed that pore-water toxicity was organic in nature. Fractionation and subsequent mass spectral identification of peaks in the toxic fraction indicated that PCBs, PAHs, and unknown compounds were present. Comparisons of PAH LC50s and PAH concentrations in this fraction indicated that the toxicity was not due to PAHs because the PAH concentrations were much lower than the reported PAH LC50s. One unknown peak was positively identified as bis(2-ethylhexyl) phthalate, and the other tentatively identified as pyrazole. Toxicity tests and comparison of toxicity in the blank and toxic fractions eliminated the two “unknowns” as toxic causal agents. We determined the range of PCB LC50s to fall between 10 and 110 ppb for Mysidopsis bahia and Ampelisca abdita. Concentrations of PCBs for the toxic fractions ranged from 12 to 27 ppb. This range falls within our observed PCB LC50s for M. bahia and A. abdita. Based upon these PCB concentrations, we concluded that PCBs were the acute toxic agents in NBH pore waters. Other compounds in the toxic fractions, or compounds that coeluted and were undistinguished from PCBs had minor contributions to the measured toxicity.
Immunotoxicity of environmentally relevant mixtures of polychlorinated aromatic hydrocarbons with methyl mercury on rat lymphocytes in vitro
Authors: Omara Felix Olima , Brochu Charles , Flipo Denis , Denizeau Francine , Fournier Michel 
Published: March 2010

Abstract
The immunosuppressive effects of methyl mercury (MH), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) are well established at high exposure levels but unclear at low exposure levels. We exposed Fischer 344 rat splenocytes, thymocytes, and peripheral blood lymphocytes in vitro for 72 h to MHg (0.1, 2 μg/ml), PCDD/PCDF mixtures (1, 15 pg/ml) of three PCDDs (2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,2,3,7,8-pentachlorodibenzo-p-dioxin, and 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin) and two PCDFs (2,3,7,8-tetrachlorodibenzofuran and 1,2,3,7,8-pentachlorodibenzo-furan), three Aroclor® (1242, 1254, 1260), PCB mixtures (0.01, 0.5 μg/ml), or combinations of MHg/PCB/PCDD/PCDF mixtures Mitogenic responses of lymphocytes to concanavalin A, phytohemagglutinin, or lipopolysaccharide/dextran sulfate were determined by 3H-thymidine uptake; cytotoxicity and intracellular Ca2+ were determined by flow cytometry. Methylmercury (2 μg/ml and PCB/ PCDD/PCDF mixtures with 2 μg/ml MHg decreased the viability of splenocytes to 57 and 40% at 4 and 24 h, respectively. Basal intracellular calcium ion levels were unaffected by the treatments. Methylmercury suppressed the responses of lymphocytes to T and B cell mitogens. All combinations of MHg/PCB/PCDD/PCDF mixtures decreased mitogenic responses to levels similar to those to MHg alone. In contrast, PCB and PCDD/PCDF mixtures did not suppress but augmented responses of splenocytes and peripheral blood lymphocytes to T cell mitogens. Overall, no interactive toxicity was observed with MHg/PCB/PCDD/PCDF mixtures on cytotoxicity and lymphocyte mitogenic responses. Therefore, MHg may pose a greater threat than organochlorines to the mammalian immune system.
Persistence and toxicological effects of pesticides in topsoil: Use of the equilibrium partitioning theory
Authors: Ronday Rob , Van Kammen-Polman Annie M M , Dekker Abraham , Houx Norbert W H , Leistra Minze 
Published: March 2010

Abstract
Three parameters for indicating toxicologic risk of pesticides to soil organisms were compared: the traditional total content parameter, the equilibrium partitioning approach, and the pore-water concentration parameter. The relevance of each parameter was tested using different soil types and prolonged chemical–soil contact time by relating the results to bioavailability as measured in toxicity tests. The pesticide concentration measured in the soil pore water could be shown to correspond strongly with toxicologic effects on the soil organism Folsomia candida, irrespective of soil type and chemical–soil contact time. This relationship is predicted by the equilibrium partitioning theory and so this aspect of the theory could be validated in this study for pesticides in soil. However, the theory's assumption of equilibrium (which implies that the bioavailable fraction of the chemical is constant with time and can be calculated using one particular soil to pore-water partition coefficient) could not be justified in this study. Although organic matter normalization reduced soil-to-soil differences, it did not account for the time-related decrease in bioavailability that was found in two of the four soil–chemical combinations investigated. As a consequence, pore-water concentrations calculated from chemical content measurements in soil and a partition coefficient obtained in short-term laboratory experiments may not be a good estimate for sorption or toxicologic effects on a longer term. The suggestion is made to measure the concentration of chemical in pore water directly and to use water-only toxicity values as a basis for soil quality criteria.
Effect of oxygen status on pesticide transformation and sorption in undisturbed soil and lake sediment
Authors: Vink Jos P M , van der Zee Sjoerd E A T M 
Published: March 2010

Abstract
The behavior of four chemically distinctly different pesticides (aldicarb, simazine, mecoprop, and phenoxic acid [MCPA] was investigated under simulated redox conditions that occur at the terrestrial–aqueous interface. Sorption was measured in soil and lake sediment and in pure and combined pesticide solutions to study effects of competition. Transformation was investigated in undisturbed soil microcolumns and in anaerobic lake sediment. Using an air-tight nitrogen incubator, oxygen concentrations were varied from 20.8% (ambient) to less then 0.01 % v/v O2, while redox potentials varied from +330 to —120 mV. Aldicarb was transformed more rapidly under anaerobic than under aerobic conditions. Under low oxygen conditions, both reductive and oxidative metabolites were formed. Simazine showed some reductive transformation, but the overall transformation rate decreased with decreasing O2 concentrations. A pronounced redox effect was shown for both mecoprop and MCPA. With decreasing oxygen concentrations, transformation rates decreased from 0.173 to less than 0.001 d−, monitored over 200 d. These compounds, which are considered improbable leachers based on their short aerobic half lifes, appear to be more persistent in low-oxygenous conditions. It is shown that a period of oxygen inhibition could be survived by the responsible soil microorganisms and was followed by accelerated transformation of the compound when oxygen became abundant again. No relationship was observed between sorption affinity and transformation rate. The effect of redox conditions that occur along the pesticide's emission route appears to be an important screening parameter to assess environmental risks.
A multi-laboratory evaluation of analytical methods for estimating bioconcentratable contaminants in effluents, tissues and sediments
Authors: Wong Diana C L , van Compernolle Remi , Chai Eric Y , Fitzpatrick Richard D , Bover W James 
Published: March 2010

Abstract
The U.S. Environmental Protection Agency has developed draft guidance for the assessment and control of bioconcentratable contaminants in surface waters that are not covered by water quality criteria. The guidance document contains analytical procedures for identification and quantification of bioconcentratable contaminants in effluents, sediments, and tissues. These analytical procedures were the subject of a multilaboratory round-robin study in 1992. The results reported in this article are from five of the 12 laboratories that completed the round-robin study. Analyses of data from the five laboratories show that analytical variance explains the large observed intralaboratory variability in surrogate recoveries. Sample variance is minor relative to analytical and laboratory variances. All five laboratories isolated and positively identified only three of eight spiked compounds at &gt;50% frequency using the proposed analytical procedures and gas chromatography–mass spectrometry library search method. The inability of the library search method to detect some of the reference spike chemicals is a concern because the methods are intended to detect unknown bioconcentratable chemicals. In general, the multistep procedure for each matrix was complex, prone to analyte loss, time intensive, and analytically demanding. Specific procedural problems and alternative methods are discussed, and recommendations for improvement are presented.
Survival and ecological effects of genetically engineered Erwinia carotovora in soil and aquatic microcosms
Authors: Palmer Sarah , Scanferlato Vjera S , Orvos David R , Lacy George H , Cairns John 
Published: March 2010

Abstract
The release of genetically engineered organisms into the environment has raised concerns about their potential ecological impact. In this study, genetically engineered Erwinia carotovora strains expressing varying levels of reduced phytopathogenicity and wildtype E. carotovora strains were used in aquatic and soil microcosms to assess the survival, intraspecific competition, and effects upon specific groups of indigenous bacteria. In aquatic microcosms, the densities of Erwinia genetically engineered organisms (GEMs) and wildtype strains declined and fell below the detectable limit of plate counts 15 d after the microcosms were inoculated. In aquatic microcosms, engineered E. carotovora did not exhibit a competitive advantage over the wildtype. The effect of engineered and wildtype E. carotovora on densities of total and selected bacteria was not significantly different. Treatment with engineered E. carotovora did not change biomass values of the receiving community but did cause a transitory increase in metabolic activity. In aquatic microcosms, the inability of genetically engineered E. carotovora to persist, displace resident species, or affect the metabolic activity of aquatic communities indicates the low risk of adverse ecological consequences in aquatic ecosystems. Unlike previous investigations involving soil microcosms, densities of both the genetically engineered and wildtype E. carotovora remained at detectable levels over 60 d in both agricultural clay and forest loam soils. The type of soil significantly affected the survival of the GEM and the wildtype. The sorptive properties of clay particles, as well as low concentrations of soil nutrients and organic matter, may have contributed to the unexpected patterns of GEM and wildtype survival.
Polynuclear aromatic hydrocarbon metabolism in soils: Relationship to soil characteristics and preexposure
Authors: Carmichael Lisa M , Pfaender Frederic K 
Published: March 2010

AbstractThe fate of radiolabeled ([14C]) phenanthrene, pyrene, benz[a]anthracene, chrysene, and benzo[a]pyrene was examined in five soils, four of which had previous exposure to polycyclic aromatic hydrocarbons (PAHs). The soils and [14C]PAHs studied represent a range of characteristics (fraction of soil organic carbon [foc] and PAH solubility) that can potentially impact contaminant fate. Fates of [14C]PAHs examined in slurry microcosms included mineralization, production of water-soluble metabolites and their polarity, cellular incorporation, and the association of [14C]PAHs with soils, all compared to an abiotic control. The soils all contained active heterotrophic communities and the contaminated soils had sizable populations of PAH-degrading microorganisms, measured by the [14C]-most probable number assay. All [14C]PAHs, except [14C]benzo[a]pyrene, were readily mineralized in most of the preexposed soils, whereas in the uncontaminated soil, less than 5% of each [14C]PAH was mineralized. In the adapted soils, mineralization, after 8 weeks of incubation, accounted for 30 to 60% of [14C]phenanthrene, 10 to 55% of [14C]pyrene, 5 to 40% of [14C]benz[a]anthracene, 10 to 50% of [14C]chrysene, and 2 to 9% of [14C]benzo[a]pyrene added to the microcosms. Metabolite production and cellular incorporation usually accounted for less than 10% of the added [14C]PAH. The fate of PAHs was usually not related to measurements of microbial community size, characteristics of the PAH (water solubility and Kow), and many characteristics of soils (soil foc and PAH concentration). The fraction of silt and clay in the soils for each soil–PAH combination, however, was negatively related to the extent of added [14C]PAH mineralized and the amount solvent extractable from the soil, and positively related to the amount of [14C]PAH remaining in soils after extraction.
Effects of sublethal copper exposure on muscle energy metabolism of common carp, measured by 31P-nuclear magnetic resonance spectroscopy
Authors: De Boeck Gudrun , Borger Robert , Van der Linden Annemie , Blust Ronny 
Published: March 2010

Abstract
The effects of shock and subchronic exposure(1 week) to 0.36 ± 0.08 and 1.31 ± 0.22 μM of copper on the energy metabolism of common carp (Cyprinus carpio) were studied by means of in vivo 31P-nuclear magnetic resonance spectroscopy (31P-NMRS). During the experiments, fish were submitted to an additional hypoxic challenge and recovery from this challenge was followed for 6 hs. During all experiments adenosine triphosphate (ATP) levels remained stable. Under control conditions, levels of phosphocreatine (PCr) and inorganic phosphate (Pi) recovered rapidly after the hypoxic challenge; however, full recovery was not observed after shock copper exposure. Also, intracellular pH (pHi) did not recover from the hypoxic challenge after shock exposure. After 1 week of exposure the fish had clearly developed an increased tolerance to copper. At both copper concentrations, PCr and Pi levels returned to resting levels after the hypoxic challenge, but at the highest copper concentration PCr to Pi ratios were significantly lower than PCr to Pi ratios in the control group and levels of PCr and Pi were very unstable. At the high copper concentration, pHi was clearly decreased compared to the control group even before the hypoxic challenge.