bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the capacity for development of atrazine tolerance in periphyton from a swedish freshwater site as determined by inhibition of photosynthesis and sulfolipid synthesis
Authors: Nyström Bo , Paulsson Maria , Almgren Klara , Blank Hans 
Published: March 2010

AbstractPeriphyton communities were established onglassdisksks undëcontinuous exposure tatrazine (0.056–3.2 μM, or 12–700 μg/L) in a microcosm flowthrough system with water from the Göta Älv river in Southern Sweden. The effects of atrazine on chlorophyll a content, ash-free dry weight, algal species composition, and adenine and thymidine incorporation activity were determined after 4 weeks of continuous exposure. Tolerance of the algal community to atrazine was also determined by short-term inhibition of photosynthesis and sulfolipid synthesis. The no-effect concentrations for the long-term exposure as determined with the different methods were between 0.040 and 0.28 μM of atrazine. The algal community seemed to have a low potential for development of tolerance to atrazine. Tolerant algae, however, seemed to have some capacity to replace the more sensitive species at low long-term exposure (0.056–0.56 μM), which was reflected in a small but consistent increase of community tolerance. At higher concentrations, no algal species remained unaffected by atrazine, and consequently, no further increase in community tolerance was possible. On the contrary, the algal community appeared to become more sensitive.
Evaluation of planar halogenated and polycyclic aromatic hydrocarbons in estuarine sediments using ethoxyresorufin-O-deethylase induction of H4IIE cells
Authors: Gale Robert W , Long Edward R , Schwartz Ted R , Tillitt Donald E 
Published: March 2010

AbstractPolycyclic aromatic hydrocarbons (PAHs) and planar halogenated hydrocarbons (PHHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were determined in fractionated sediment extracts from the Hudson-Raritan estuary and Newark Bay, New Jersey, USA, as part of a comprehensive risk assessment. Contributions of PCDDs/PCDFs, PCBs, and PAHs to the total toxic equivalents (TEQs) were measured using an H4IIE bioassay and calculated from instrumentally determined concentrations using international toxic equivalency factors. The H4IIE TEQs of whole and fractionated extracts were compared to calculated TEQs to investigate the applicability of the bioassay approach for evaluating 7-ethoxyresorufin-O-deethylease induction by PHHs and PAHs present together in complex mixtures. Although 2,3,7,8-tetrachloro-dibenzo-p-dioxin contributed from 41 to 79% of the calculated TEQs from PCDDs/PCDFs and planar PCBs in all sediments sampled, the PAH-containing fractions accounted for &gt;80% of the total TEQs determined either instrumentally or by bioassay. Calculated TEQs from PAHs, based on reported toxic equivalency factors for only seven PAHs, were severalfold greater than the bioassay-derived TEQs of PAH-only fractions of the sediment extracts. Significant correlations were observed between bioassay and instrumentally determined toxic equivalents in the more purified fractions but not in fractions only purified by size-exclusion or argentate chromatographies alone.
Diazinon dissipation from vegetation, occurrence in earthworms, and presence in avian gastrointestinal tracts collected from apple orchards following D-Z-N® 50W application
Authors: Cobb George P , Mellott Ron , Brewer Larry W , Bens Catherine M , Kendall Ronald J 
Published: March 2010

AbstractComprehensive residue determinations weremade in biota inhabiting orchards receiving diazinon application as part of ecotoxicology studies in the United States. The states of Washington and Pennsylvania served as study areas representing different climatic and agricultural practices. Mean diazinon application was 3.0 to 3.1 kg a.i./ha in the orchards, and a subsequent exponential reduction in concentrations occurred on vegetation. Diazinon was present in earthworms following application, and 23 of 25 avian species evaluated in treatment orchards contained diazinon in their gastrointestinal (GI) tracts. Diazinon residues were present in 18 of the 20 avian species that were represented by more than one sample. Quantifiable residues were present in 17 of the bird species. Earthworms from Pennsylvania orchards contained more frequent and higher diazinon concentrations than did earthworms from Washington orchards (p &lt; 0.005). Passerine exposure to diazinon was not different when comparing diazinon concentrations in individual species between the two geographic regions (0.23 &lt; p &lt; 0.06). Exposures were different for American robins and European starlings (p = 0.03) in Washington and for Northern cardinals and European starlings (p = 0.03) in Pennsylvania. Residues in GI tracts suggest that lethal exposures were limited to the day of application and the 4 d following application. Data indicate that, under conditions of repeated diazinon application, ingestion of earthworms poses risks to passerines.
Effect of irradiance spectra on the photoinduced toxicity of three polycyclic aromatic hydrocarbons
Authors: Diamond Stephen A , Mount David R , Burkhard Lawrence P , Ankley Gerald T , Makynen Elizabeth A , Leonard Edward N 
Published: March 2010

AbstractPhotoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events underlying phototoxicity. This suggests that variation in light spectra present in natural waters, arising from variation in dissolved organic carbon composition, is an important determinant of phototoxicity risk in specific, PAH-contaminated waterbodies. To quantify the effect of environmentally realistic variation in light spectra on toxicity, brine shrimp (Artemia salina) assays were conducted under various light spectra and with three PAHs (pyrene, fluoranthene, and anthracene) of known phototoxicity potential. In these spectral assays, the total ultraviolet light present was equivalent; only the spectral characteristics varied. Based on the absorbance spectra of these PAHs, it was predicted that toxicity, quantified using immobilization as the endpoint, would vary significantly among light spectra in pyrene assays, but not in anthracene assays, and that variation in toxicity in fluoranthene assays would be intermediate. The results supported these assumptions. In the pyrene exposures, the glass filter time to 50% population immobilization (IT50) (39.5 min) was 117% longer than the KCr filter IT50 (18.2 min). In the fluoranthene exposures, the glass filter IT50 (49.5 min) was 27% longer than the KCr filter IT50 (39.1 min). In the anthracene exposures, the glass filter IT50 (62.2 min) was not statistically different from the KCr filter IT50 (63.8 min). Comparison of these results with the results of assays conducted under neutral-density filters (that change intensity but not spectral distribution) demonstrate that multiplying spectral intensity by wavelength-specific absorbance accurately predicts relative photoinduced toxicity among the experimental treatments. These results indicate that quantifying the spectral characteristics of PAH-contaminated aquatic environments may be an important component of risk assessment at these sites.
Genotype and toxicity relationships amongHyalella azteca: I. Acute exposure to metals or low pH
Authors: Duan Yihao , Guttman Sheldon I , Oris James T , Bailer A John 
Published: March 2010

AbstractComparative genotype and toxin interactions at three polymorphic enzyme loci were examined in a laboratory population of amphipods (Hyalella azteca) during acute exposure to cadmium, zinc, copper, lead, or low pH. Significant toxin-genotype interactions were observed using logistic regression to model mortality in ten of 15 analyses. Both stressor-specific and nonspecific modes of selection were observed. In general, low pH selected for different genotypes than those selected by metals, especially zinc. Different modes of selection were also observed when amphipods were exposed to different metals. These results suggest that exposure to low pH would significantly reduce the ability of H. azteca to survive subsequent contamination by metals; exposure to stressors in the reverse order would also compromise a population's chance of survival. A genetic distance analysis showed that the magnitude of genetic differentiation consistently increased among survivors compared with that of the initial populations. These increases in genetic divergence estimates suggest that acute exposure to metals or low pH may have an evolutionarily significant impact on the species. They also suggest that both genotype frequency and genetic distance measures (based on allozyme data) may be used as bioindicators for environmental monitoring programs. Validation of such bioindicators requires an understanding of the population's genetic background, genetic structure, and history.
Multimedia level-III partitioning and residence times of xenobiotics in water-rich and water-poor environments
Authors: Breitkopf Cornelia , Kühne Ralph , Schüürmann Gerrit 
Published: March 2010

AbstractThe environmental fate of 10 compounds covering a wide range of intrinsic persistence and volatility is studied with a multimedia level-III fugacity model at two system temperatures (293 and 282 K) using water-rich and water-poor model environments and standard emission scenarios to air and water, respectively. The resultant level-III partitionings depend significantly on the entry mode and on the relative compartment sizes, and the variation with system temperature is more pronounced for polar compounds and when air is the primary discharge compartment. For example, the steady-state portion in soil of airborne phenol varies from 21 to 89%, whereas waterborne phenol resides in water at a rate of 100% in both water-rich and water-poor environments. For some compounds, the residence time (considering both advection and degradation) is substantially affected by intermedia transport processes such as rainfall. With airborne atrazine, the regional residence time is comparable to that of DDT and significantly greater than the ones of hexachlorobenzene, polychlorinated biphenyl 28, and lindane, although the latter have much longer media-specific half-lives and much greater hydrophobicity. The discussion includes detailed analyses of the compound properties and their impact on the level-III environmental fate.
Multivariate modeling of polychlorinated biphenyl–induced CYP1A activity in hepatocytes from three different species: Ranking scales and species differences
Authors: Andersson Patrik L , van der Burght Aafje S.A.M. , van den Berg Martin , Tysklind Mats 
Published: March 2010

Abstract
Cytochrome P4501A–induced activity of 20 selected polychlorinated biphenyls (PCBs) was evaluated by measuring ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase activities induced in the hepatocytes of cynomolgus monkeys, male castrated pigs, and chicken embryos. Quantitative structure-activity relationships have been established, including 52 physi-cochemical parameters and different measures of the dose-response curves. Relative effect potencies are predicted for the 154 tetra-to hepta-PCBs and reported for the most potent congeners according to both EC50 and maximal response values. Important physicochemical parameters of the PCBs as related to the modeled activity are parts of their ultraviolet absorption spectra, the Henry's law constant, the ionization potential, and the octanol-water partition coefficient. Interspecies differences were found in terms of varied sensitivity to different structural subgroups of the compounds. The chicken hepatocyte assay showed the most specific structure-activity relationship, with high activity for the non-ortho PCBs, whereas the pig hepatocytes responded even for some di- to tetra-ortho PCBs. An interspecies response, the principal induction potency, is presented for the 41 most potent PCBs. These responses showed strong correlation with the toxic equivalency factors and are likely to be useful in risk assessment of the compounds.
Comparative measures of the toxicity of component chemicals in aircraft deicing fluid
Authors: Cornell Jeffrey S , Pillard David A , Hernandez Mark T 
Published: March 2010

Abstract
Acraft deicingoperationsarea necessarypart of safe air travel, but release large quantities of aircraft deicing fluids (ADFs) to the environment. Effective measures to mitigate the environmental impacts of deicing operations are hindered because of the negative effects some ADF chemicals have on treatment systems and because of the poorly characterized toxicity of ADF components. This research investigated the contributions of environmentally significant concentrations of selected ADF components to the toxicity of ADF-containing waste streams, and to the inhibition of biodegradation of propylene glycol (PG), the most important component of ADF. The component chemicals studied were PG, the corrosion inhibitor 4(5)-methylbenzotriazole (MeBT; common name: tolyltriazole), and proprietary mixes of corrosion inhibitors, buffers, and surfactants referred to as the additive package or AdPack. Relative to PG alone, the different additives increased the toxicity of ADF and decreased PG biodegradation rates. In enrichments of soil microorganisms acclimated to ADF, the MeBT component significantly decreased cell growth rates and yields, and inhibited PG biodegradation to a greater extent than the AdPack. Microtox® tests indicated that MeBT is the ADF component most toxic to microorganisms. However, acute aquatic toxicity tests indicated that the AdPack components were more toxic than MeBT to Ceriodaphnia dubia and Pimephales promelas, although both components were more toxic than PG alone.
Apportionment of polycyclic aromatic hydrocarbon sources in lower Fox River, USA, sediments by a chemical mass balance model
Authors: Su Ming-Chien , Christensen Erik R , Karls Jay F , Kosuru Sailaja , Imamoglu Ipek 
Published: March 2010

Abstract
Four sediment cores were collected from the lower Fox River, Wisconsin, USA, to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) using a chemical mass balance model. The cores, which were obtained in 1995 from areas close to Green Bay, Wisconsin, USA, had total PAH concentrations between 19.3 and 0.34 ppm. To determine historical trends of PAH inputs, 210Pb and 137Cs dating was used, and elemental carbon particle analysis was done to characterize particles from the combustion of coal, wood, and petroleum. Source fingerprints were taken from the literature. Our results indicate that coke oven emissions, highway dust, coal gasification, and wood burning are likely sources of PAHs in the lower Fox River. Coke oven emissions are in the range of 40 to 90% of total PAHs, and this fraction decreases from 1930 to 1990, except in core Fox River–A (FR-A). The overall highway dust (HWY) contribution is between 10 and 75%, and this fraction increases from 1930 to present, except in core FR-A. The wood burning (WB) contribution (i.e., wood burning or coal gasification) is less than 7% in cores FR-B, FR-C, and FR-D. In core FR-A, a maximum (≈23%) is found around 1960. The contribution of wood burning has changed from less than 6% in 1950 to between 3 and 10% in 1995. Evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene, with a half-life of approximately 0.5 years has been found at the site of core FR-D, which is the shallowest (1.1 m) of the four core sites.
Long-term fate and bioavailability of sediment-associated 2,3,7,8-tetrachlorodibenzofuran in littoral enclosures
Authors: Currie Robert S , Fairchild Wayne L , Holoka Morris H , Muir Derek C G 
Published: March 2010

AbstractThe fate and bioavailability of 2,3,7,8-tetrachlorodibenzofuran (TCDF; 4,6-tritium labeled) was examined over a 3-year (852-d) period in littoral enclosures (34 m3) in a small oligotrophic lake in the Experimental Lakes Area. Tetrachlorodibenzofuran was added as a single dose (10.4 g/34 m3) or as five small multiple additions over a 5-d period in a sediment slurry. Tetrachlorodibenzofuran was rapidly redistributed, mainly to bottom sediments (water column t½ ∼1.8 d), reflecting removal on settling particles. Between 0 and 120 d, 80 to 90% of TCDF in the water column was associated with particles (&gt;1 μm). The highest concentration of TCDF in suspended particles was consistently observed in the smallest size fraction (0.22–1 μm) at 326 to 464 d posttreatment. Mode of addition had no effect on TCDF concentrations in water (unfiltered) or surficial sediments (0–2 cm) or pore waters throughout the experiment. Mean TCDF concentrations in surficial sediment (0–120 d) were 1,830 ± 1,180 pg/g (organic carbon [OC] basis), whereas they averaged 1,260 ± 596 pg/g OC from 318 to 851 d posttreatment. Increasing concentrations of TCDF in lower sediment layers at 852 d suggests that TCDF was either diffusing into the sediment or undergoing burial. Fugacity (f) calculations indicated that the TCDF in enclosures shifted from disequilibrium favoring the water column (days 0–9) to a disequilibrium with respect to bottom sediments (fwate/fsediment = 0.06–0.003) from day 21 onward. Initially, TCDF was more bioavailable to filtering and deposit feeders (mussels, Chironomidae, Hexagenia sp., and zooplankton) in enclosures receiving multiple additions; however, differences were rarely statistically significant. Concentrations of TCDF in all organisms were initially high, and they decreased in later sampling periods. Biota–sediment-accumulation factors (BSAFs) in mussels and crayfish were &gt;1 in the early sampling periods, which reflected greater bioavailability of the added particle-borne TCDF. By 851 d, BSAFs had declined to 0.02 to 0.04, reflecting removal of TCDF from the water column and from surficial sediments.
A new method for measuring carbonate radical reactivity toward pesticides
Authors: Huang Jiping , Mabury Scott A 
Published: March 2010

Abstract
The carbonate radical is produced from the scavenging of the hydroxyl radical by carbonate/bicarbonate and is strongly electrophilic toward electron-rich compounds such as aromatic amine and sulfur-containing compounds. Carbonate radical reactivity (CO3⋅−) was measured by setting up a competition between a chemical of known reactivity and a compound with unknown reactivity toward CO3⋅−. The carbonate radical was produced using a novel method whereby KOONO (potassium peroxonitrite) was dissolved into 0.01 NaHCO3 solution initially producing a HO⋅, which was rapidly scavenged by HCO3⋅−, yielding CO3⋅− CO3⋅− production was monitored using a stopped-flow spectrometer at the absorption band for CO3⋅− of 600 nm. Results using this competition kinetic method indicated the second-order rate constants for substituted anilines corresponded to reference values with a relative error less than 10%. Using σpara+ values, the rate constants of substituted anilines at pH 9.0 correlated well (R2 = 0.98) with the Hammett equation yielding ρ = −0.89. To measure the reactivity of pesticides toward the carbonate radical, p-nitroaniline (PNA) was selected as the standard competitor. Of the nine pesticides tested, fenthion was the most reactive, followed by phorate, with rate constants above 107/M/s. Fluometuron and atrazine were of intermediate reactivity, and methyl parathion was one of the least reactive.
Dietary accumulation and quantitative structure-activity relationships for depuration and biotransformation of short (C10), medium (C14), and long (C18) carbon-chain polychlorinated alkanes by juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Fisk Aaron T , Tomy Gregg T , Cymbalisty Chris D , Muir Derek C G 
Published: March 2010

Abstract
Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to three [14C]-polychlorinated alkanes (PCAs) (C10H15.3Cl6.7, C14H23.3Cl6.7, and C18H31.4Cl6.6) at nominal concentrations of 1.5 and 15 μg/g for 40 d, followed by 160 d of clean food, to measure bioaccumulation parameters and biotransformation. These PCAs are identical in carbon-chain length and chlorine content to industrial chlorinated paraffin products, although their method of synthesis differs from that of chlorinated paraffin products. Half-lives ranged from 26 to 91 d, biomagnification factors ranged from 0.9 to 2.8, and both exhibited increasing trends with increasing carbon-chain length. Data from this work and others on PCAs were used to determine biotransformation rates and to examine quantitative structure-activity relationships for bioaccumulation and biotransformation. Quantitative structure-activity relationships developed for half-life and biomagnification factor showed positive linear relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log Kow. The PCA biotransformation rates (per day) ranged from −0.00028 to 8.4 and exhibited negative relationships with the number of carbon atoms, of chlorine atoms, of total carbon and chlorine atoms, and log Kow. Results suggest that PCAs with a total number of carbon and chlorine atoms between 22 and 30 are slowly, or are not, biotransformed in juvenile rainbow trout. Increasing carbon-chain length and chlorine content result in greater bioaccumulation of PCAs by reducing partition-based (i.e., diffusion) and metabolic (i.e., biotransformation) elimination processes. High bioaccumulation potential and low biotransformation rates of medium (C14-18) and long (C18-30) carbon-chain PCAs and highly chlorinated PCAs indicate that information is needed regarding the environmental concentrations of these PCAs in aquatic food chains.
Teeth as biomonitors of soft tissue mercury concentrations in beluga, Delphinapterus leucas
Authors: Outridge Peter M , Wagemann Rudolph , McNeely Roger 
Published: March 2010

Abstract
This paper reports relationships between bulk Hg concentrations in the tooth cementum and soft tssues of fee-living beluga (Delphinapterus leucas). Total Hg levels were determined in slivers of cementum using a solid-sample Hg analyzer, a recent advance in Hg analysis that avoids acid predigestion. Tooth Hg concentrations ranged up to about 350 ng/g dry weight and were significantly correlated with Hg levels in kidneys, liver, muscle, and muktuk (skin) and with the age of the animals. The Hg/Se ratio in liver, the organ with the highest Hg concentrations, may have been an important determinant of tooth Hg. At hepatic Hg/Se molar ratios ≥0.6, tooth Hg increased steeply, suggesting that Hg in teeth may reflect physiologically available Hg that was not bound in the liver and that was circulating in the bloodstream. This Hg/Se ratio was exceeded in most beluga aged ≥20 years. The results indicate that teeth can be used as biomonitors to reconstruct temporal and geographic trends in the soft tissue Hg concentrations of beluga, provided that the age structures of the different populations are known.