bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil contamination and bioaccumulation of inorganics on petrochemical sites
Authors: Schroder Jackie L , Basta Nicholas T , Lochmiller Robert L , Rafferty Dan P , Payton Mark , Kim Soochong , Qualls Charles W 
Published: March 2010

AbstractPetrochemical waste contains inorganic contaminants that can pollute soil and pose ecological risks to wildlife. Few studies have evaluated bioaccumulation of inorganic contaminants by small mammals from soil contaminated with petrochemical waste. In this study, we determined the extent of soil contamination with inorganics, the bioaccumulation of metals and F in bone of cotton rats (Sigmodon hispidus), and the relationship between contaminants in soil and in bone of cotton rats on petrochemical waste sites. Cotton rats and soils from 12 petrochemical-contaminated and matched reference sites were analyzed over a three-year period. The number of petrochemical-contaminated sites with soil contamination (in parentheses) were Zn (12), Pb (9), Cr (9), Cu (8), F (7), Ni (7), Sr (6), Ti (5), V (5), Co (3), Ba (3), and Cd (2). Lead and F were the most frequently bioaccumulated contaminants in cotton rat bones. Bone Pb of 3.8 to 63.4 mg/kg was 2- to 42-fold and bone F of 830 to 3,680 mg/kg was 5- to 23-fold greater than mean bone Pb and F from reference sites. Bone Pb and F showed a seasonal trend with winter greater than summer levels. Bone F was an accurate predictor of dental fluorosis when bone F was low (&lt; 1,000 mg/kg, no fluorosis) or high (&gt;3,000 mg/kg, fluorosis) but was inaccurate for intermediate bone F (1,000–3,000 mg/kg). The prevalence of dental fluorosis on F-contaminated sites was 50% higher in winter than summer. Strong relationships were found between bone F and HCl-extractable F (r = 0.70) and bone F and total content of F (r = 0.85) in F-contaminated soils. Land disposal of petrochemical wastes should limit the amount of inorganic contaminants applied to soil.
Metabolic response of Lumbriculus variegatus to respiratory uncoupler in cold and anoxic water
Authors: Penttinen Olli-Pekka , Kukkonen Jussi V K 
Published: March 2010

Abstract
A direct calorimetry approach was applied to compare physiological interaction of pentachlorophenol (PCP) with the energy metabolism under anoxia and normoxia in the aquatic oligochaete worm Lumbriculus variegatus. In normoxia, heat dissipation begins to accelerate 10 h after the onset of PCP exposure until it settles at a new plateau level, and shows a twofold increase from the nonimpact rate. In anoxia, heat output was suppressed down to a level of ∼18% (7°C) of normoxia. An anoxic PCP exposure did not produce any notable changes in the heat output, and the amount of chemical accumulated in tissues was only a fraction (18%) of that accumulated in normoxia. Whether the inhibition of the physiological response during anoxia was due to a shift to anaerobic metabolism or to reduced accumulation in tissues, or combination of both factors, was unclear.
Transport and fate of organochlorines discharged to the salt marsh at Upper Newport Bay, California, USA
Authors: Masters Patricia M , Inman Douglas L 
Published: March 2010

Abstract
Despite long-term monitoring of water quality in the coastal lagoons of California, USA, the fate of organochlorines discharged from agricultural and urban sources to salt marsh habitats has received little attention. We measured organochlorine concentrations in Upper Newport Bay marsh and channel sediments and salt marsh plants. Sediment grain-size analyses show that organochlorines are fractionated and concentrated in the organic material traveling with the clay fraction of the washload discharged into the bay from San Diego Creek. Hydrophobic compounds such as DDT are not associated with the sand and silt fractions. The most frequently detected analyte was p,p′-1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), occurring in 100% of the sediment samples and 87% of the plant root samples. Maximum concentrations in sediment were 122 ng/g (dry wt) for DDE and 162 ng/g DDT plus metabolites (∑DDT) in salt marsh deposited since 1980. Ratios of DDT to its metabolites suggest that anaerobic degradation of DDT occurs in the cordgrass (Spartina foliosa Trin.) sediments. Cordgrass and pickleweed (Salicornia virginica L.) partition organochlorine residues to the root epidermis, attaining values of 50,000 ng/g lipid for ∑DDT and 80,000 ng/g lipid for heptachlorepoxide (1,4,5,6,7,8,8-heptachloro-2,3-epoxy-3α,4,7,7α-tetrahydro-4,7-methanoindan).
Genetic diversity ofClethrionomys glareoluspopulations from highly contaminated sites in the Chornobyl region, Ukraine
Authors: Matson Cole W , Rodgers Brenda E , Chesser Ronald K , Baker Robert J 
Published: March 2010

AbstractAt radioactive sites, at least two mechanisms may affect the genetic diversity of populations of a given species. Increased mutation rates due to radiation exposure may increase the amount of genetic diversity in a population. Alternatively, population bottlenecks exacerbated by environmental degradation may lead to a reduction of diversity. The relationship between these two contradictory forces is complex. To explore this relationship, long-term monitoring of a genetic marker within a population is needed. To provide baseline data on the population genetics of the bank vole (Clethrionomys glareolus) living in the most contaminated regions at Chornobyl, Ukraine, we have sequenced 291 base pairs of the mitochondrial DNA control region. Bank voles were chosen as a model system because they have the highest levels of internal dose of cesium-134, cesium-137, and strontium-90 within the Chornobyl exclusion zone. We sampled three geographic sites, which were Oranoe, a reference site with virtually no radioactive contamination (&lt;2 Ci/km2), and two highly contaminated sites, Glyboke Lake and the Red Forest (both 1,000 Ci/km2). Genetic diversity in the population from Red Forest (0.722 ± 0.024) was significantly greater than at the Oranoe reference site (0.615 ± 0.039), while genetic diversity at Glyboke Lake (0.677 ± 0.068) was intermediate. It is concluded that long-term studies of historical and demographic characteristics for experimental and reference populations are required in order to employ population genetics to understand the biological impact of environmental contaminants on the genetics of natural populations.
Effects of sorption on the biodegradation of 2-methylpyridine in aqueous suspensions of reference clay minerals
Authors: O'Loughlin Edward J , Traina Samuel J , Sims Gerald K 
Published: March 2010

Abstract
The effects of sorption on the bioavailability of 2-methylpyridine (2-MP) were investigated by determining the biodegradation of 2-MP by an Arthrobacter sp. in aqueous suspensions of reference clay minerals and a synthetic cation exchange resin. Adsorption of 2-MP on kaolinite, illite, hectorite, montmorillonite, and Dowex® was determined by the batch equilibrium method. In general, adsorption of 2-MP was positively correlated with the cation exchange capacity of the sorbent, suggesting that sorption of 2-MP on clay minerals occurs through a cation exchange reaction via the 2-methylpyridinium ion. The biodegradation of 2-MP was most rapid in the kaolinite suspensions, followed by no clay &gt; illite ≫ Dowex &gt; hectorite/montmorillonite. With the exception of kaolinite, adsorption of 2-MP on clay minerals and Dowex reduced the rate of biodegradation. The degree of attenuation was positively correlated with the fraction of 2-MP sorbed, suggesting that sorbed 2-MP was not directly available for degradation. Desorption was not rate limiting in suspensions containing hectorite, montmorillonite, or Dowex; however, desorption may have become limiting in the kaolinite and illite suspensions. The results of this study clearly indicate that adsorption can directly affect the degradation of 2-MP in complex mineral systems.
Steady-state concentrations of carbonate radicals in field waters
Authors: Huang Jiping , Mabury Scott A 
Published: March 2010

Abstract
The carbonate radical [•CO−3] is a secondary radical that results from the scavenging of hydroxyl radical (•OH) by carbonate/bicarbonate. N,N-dimethylaniline was found to be a selective probe for measuring the steady-state concentration of this radical in a variety of natural waters. The pH, nitrate, total carbonate/bicarbonate, and dissolved organic carbon (DOC) in selected field waters were quantitatively analyzed. It was assumed that hydroxyl radicals were produced primarily from the slow photolysis of nitrate and DOC and then were scavenged by carbonate/bicarbonate that were competing with DOC. Steady-state carbonate radical concentrations [•CO−3]ss in natural waters were measured by irradiating solutions of natural waters containing N,N-dimethylaniline in a photoreactor with varying intensity as well as using natural sunlight. The measured steady-state concentration of carbonate radicals was found to be strongly dependent on light intensity and ranged from 5 × 10−15 to 10−13 M. Further kinetic analysis of the data showed that carbonate radical concentrations were related to the concentrations of nitrate and dissolved organic carbon in natural waters through a simple linear relationship.
Quality-assurance study of marine lipid-class determination using chromarod/iatroscan® thin-layer chromatography-flame ionization detector
Authors: Bergen Barbara J. , Quinn James G , Parrish Christopher C 
Published: March 2010

AbstractAn Iatroscan® thin-layer chromatography–flame ionization detector has been utilized to quantify lipid classes in marine samples. This method was evaluated relative to established quality-assurance (QA) procedures used for the gas chromatographic analysis of PCBs. A method for extracting and analyzing eight major lipid classes in the ribbed mussel (Guekensia demissus) was developed. The analytical method met the QA criteria prescribed for consistent external calibrations, low blanks, complete extraction of all lipid classes, and precise replicate analysis. Matrix and blank spikes were satisfactorily recovered (50-130%), provided that the samples contained a large enough mass (&gt;4% dry weight) of total lipids to overcome the absorption of polar lipids on glassware. The use of frozen mussel homogenate as a standard reference material was not possible because of lipid degradation, particularly of triacylglycerols and phospholipids. Also, total lipids measured gravimetrically significantly decreased in frozen samples, which could influence bioaccumulation predictions. A laboratory intercalibration was performed using a mussel homogenate and chloroform extract, which verified the accuracy of the method and the lipid-class identification. Characterizing the structure of one class of polar lipids, the acetone mobile polar lipid (AMPL), showed that it contained no ester linkages or free/sterically unhindered -OH groups; however, the AMPL did contain an ether linkage.
Effect of mass-transfer limitations on bioavailability of sorbed naphthalene in synthetic model soil matrices
Authors: Mulder Hendricus , Breure Anton M , van Andel Johan G , Grotenhuis J Tim C. , Rulkens Wim H 
Published: March 2010

Abstract
External and internal mass-transfer resistances influencing the bioavailability of sorbed naphthalene in a synthetic model matrix for soil aggregates were investigated in batch experiments in mixed reactors. Amberlite® adsorption resins (XAD4 and XAD7) were used as the synthetic model for soil aggregates. The effect of hydrodynamic conditions in the slurry phase on the diffusive transport across a stagnant film surrounding the model particles was studied. In addition, a mechanistic model was developed based on mass balances, diffusion equations, a nonlinear sorption isotherm, and microbial degradation kinetics. Experimental results could be explained well with this model. In the absence of external transfer limitations, intraparticle effective diffusion coefficients of (3.55 ± 0.10) × 10−9 m2/s and (5.29 ± 0.86) × 10−10 m2/s were determined for naphthalene in Amberlite XAD4 and XAD7, respectively.
Stability and detection of α-pinene oxide in aqueous culture medium
Authors: Kajihara Kimberly K , Amaral John A , Toia Robert F 
Published: March 2010

Abstract
Methane consumption by methanotrophic bacteria was previously shown to be temporarily inhibited by α-pinene. Based on literature considerations, loss of inhibition may be due to bacterial degradation of the monoterpene to α-pinene oxide, an anticipated metabolite. However, since α-pinene oxide is unstable in aqueous media, detection of its production by methanotrophs or other bacteria is problematic. Therefore, we used gas chromatography-mass spectrometry analysis to study the chemical breakdown of α-pinene oxide in various buffer systems (Tris[hydroxymethyl]am inomethane, 3-[N-morpholino]propanesulfonic acid, phosphate; pH 7-9) suitable for bacterial whole-cell and cell-free experiments. In every case, aqueous phase α-pinene oxide was unstable and its disappearance was accompanied by the appearance of five decomposition products in a characteristic fingerprint that was in part buffer dependent. However, this fingerprint was adequately stable in phosphate buffer such that its appearance could be used to infer the intermediacy of α-pinene oxide if produced by the bacteria at or near their optimal pH.
Effects of heavy metals and 3-methylcholanthrene on expression and induction of CYP1A1 and metallothionein levels in trout (Oncorhynchus mykiss) hepatocyte cultures
Authors: Faverney Christine Risso-de , Lafaurie Marc , Girard Jean-Pierre , Rahmani Roger 
Published: March 2010

AbstractInduction of both CYP1A1 and metallothioneins (MTs) in fish liver is increasingly being used in ecotoxicological studies. The interaction of heavy metals (Cd, Cu, Zn, Pb) with the CYP1A induction response and MT levels was studied in trout (Oncorhynchus mykiss) hepatocyte cultures. Cells were exposed to 3-methylcholanthrene (3-MC) or to increasing heavy metal concentrations or to a mixture of both (3-MC and one heavy metal). Metal cytotoxicity was assessed by the neutral red test. Ranking of toxicity was Cd(II) &gt; Cu(II) &gt; Zn(II) &gt; Pb(II) (EC50: 45, 222, 873, and 945 μM, respectively). CYP1A1 expression was monitored by ethoxyresorufin-O-deethylase (EROD) activity as well as by Western and Northern blots. As expected, 3-MC induced EROD activity in a time- and dose-dependent manner (maximal induction 5 times that of the control at 0.5 μM and after a 72-h exposure period). These data were confirmed by Western blot (intense band of 55–60 KDa) and Northern blot analyses. Induction caused by 0.5 μM 3-MC was reduced to less than 50% of control by the concomitant exposure to Cd, Cu, Pb, or Zn (EC50: from 1 μM for Cd(II) to 18 μM for Pb(II)). The MTs were significantly induced in hepatocytes exposed to heavy metals for 24 h. In the presence of 3-MC (0.5 μM), MT levels were significantly lower than those found in cells treated with metals alone at 24 h only. Our results lead to the conclusion that heavy metals significantly affect CYP expression and that a CYP1A1 inducer (3-MC) can modulate the induction of MTs. These data have to be taken into consideration in biomarker monitoring.
Impact of atrazine on organophosphate insecticide toxicity
Authors: Belden Jason B , Lydy Michael J 
Published: March 2010

AbstractAcute toxicity of selected organophosphorus insecticides (OPs; chlorpyrifos, methyl parathion, diazinon, and malathion) was determined for individual OPs and binary combinations of the OPs with atrazine to larvae of the midge Chironomus tentans. Atrazine individually was not acutely toxic even at high concentrations (10,000 μg/L); however, the presence of atrazine at much lower concentrations (40–200 μg/L) increased the toxicity of chlorpyrifos, methyl parathion, and diazinon. Atrazine did not increase the toxicity of malathion. Possible mechanisms for the synergistic toxicity found between atrazine and chlorpyrifos were investigated, including increased uptake rate and increased biotransformation into a more toxic metabolite. Although the uptake rate was increased by more than 40%, the resulting increase in toxicity would be minimal as compared to the 400% decrease estimated to occur in EC50 values for the same atrazine exposure (200 μg/L). Body residue analysis of midges exposed in vivo to atrazine and chlorpyrifos mixtures for 96 h indicated that a larger amount of metabolites was generated in atrazine treatments as compared to controls. Additionally, in vitro assays of microsomal proteins obtained from treated and control midges indicated that an increase in toxic metabolite (chlorpyrifos-O-analog) was generated in atrazine-treated midges. Therefore, the increase in toxicity is thought to be due to an increase in biotransformation rates of the OPs, resulting in more O-analog within the organism.
Do genotype responses always converge from lethal to nonlethal toxicant exposure levels? Hypothesis tested using clones of Daphnia magna straus
Authors: Barata Carlos , Baird Donald J , Miñarro Antonio , Soares Amadeu M.V.M 
Published: March 2010

Abstract
This study examines the hypothesis that genotypic differences in tolerance will converge with decreasing levels of toxicity: from lethal to sublethal responses and from high to low sublethal exposure levels of toxic chemicals. Four laboratory Daphnia magna clones and three chemicals with different modes of action and known sublethal effects—cadmium, copper, and fluoranthene—were selected to test the previously mentioned hypothesis. Specifically, we compare how genetic variability in feeding responses among the studied Daphnia clones changed across increasing nonlethal exposure levels (expressed as increased exposure levels of feeding inhibition, EC) and how these changes converge relative to acute lethal responses (expressed in terms of the 48-h LC50). Our data show that cadmium fully supports the convergence hypothesis and that data with fluoranthene may also support it. Nevertheless, the most important findings of the present study are to have provided experimental evidence that (1) lethal responses in acute exposures and sublethal responses such as feeding inhibition are not related, (2) genetic variability for sublethal responses tend to be lower than acute responses, and (3) trade-offs between low and high sublethal exposure levels rather than genetic heterogeneity governed sublethal responses. The first two findings have important implications for risk assessment if further supported with more data on other toxicants and clones since they suggest that concerns voiced about the need to include more genetic variability in chronic toxicity tests may be groundless. The third finding may indicate that selection under low and variable environmental levels of toxicants with sublethal effects of feeding may select genotypes with high phenotypic plasticity in response to toxic stress rather than genotypes that perform well within particular toxicant exposure levels.
Predictability of the toxicity of multiple chemical mixtures to Vibrio fischeri: Mixtures composed of similarly acting chemicals
Authors: Altenburger Rolf , Backhaus Thomas , Boedeker Wolfgang , Faust Michael , Scholze Martin , Grimme L Horst 
Published: March 2010

Abstract
The prediction of combined effects based on the effects of the individual components of mixtures by using the pharmacological concepts of concentration addition and independent action might be a promising tool for the risk assessment of pollutant mixtures. To analyze and compare the predictive capabilities of the reference concepts for similarly acting chemicals, the overall toxicity of a multiple mixture was determined in a bioluminescence inhibition assay with Vibrio fischeri. The mixture was composed of 16 similarly and specifically acting chemicals, anticipated to have a common mode of action via weak acid respiratory uncoupling of oxidative phosphorylation. Results show that the observed mixture toxicity is rather well predicted by both concepts. Concentration addition shows an excellent predictive power; the median effective concentration (EC50) of the mixture is predicted with an error of about 10%. Independent action, in contrast, underestimates the EC50 of the mixture by a factor of a little more than three. With respect to risk assessment procedures, it may be concluded that concentration addition gives a valid estimation of the overall toxicity for multiple mixtures with similar and specific mechanisms of action of the mixture components in this type of biotest.
Using probability of extinction to evaluate the ecological significance of toxicant effects
Authors: Snell Terry W , Serra Manuel 
Published: March 2010

Abstract
A large component of uncertainty in ecological risk assessment (ERA) arises from the disparity between the time scale of toxicity measurements and the time scale of predictions of ERA models. It is difficult to make predictions about the persistence of populations from data from short-term toxicity tests. Reproductive toxicity tests provide data about how population growth rate (r) is reduced with toxicant exposure. Although reduction in r is believed to be one of the most important effects of toxicant exposure, its ecological significance has been difficult to quantify. For rotifers, r is typically reduced by 10 to 15% at no-observed-effect concentrations (NOEC). We investigated r reductions of 0 to 30% in time series models of the dynamics of natural rotifer populations to predict probability of quasiextinction. Computer simulations showed that small reductions in r can have large effects over long time periods. This means that purportedly safe toxicant concentrations like those at NOEC levels can reduce r so that population extinction becomes much more likely. Reductions in r greater than about 30% destine rotifer populations near certain extinction within 100 years. Simulations indicate that an r reduction of 5% (EC5) approximately doubles the probability of extinction and is probably the maximum tolerable for the long-term persistence of rotifer populations. When episodic catastrophic population reductions are coupled with r reduction, probabilities of extinction are increased substantially. Several models yielded similar results, so the conclusions do not seem strongly dependent on the form of the model. Incorporating population viability analysis into ecological risk assessments could improve our ability to define conditions required for the long-term sustainability of populations.
Surfactant sorption to soil and geologic samples with varying mineralogical and chemical properties
Authors: Salloum Myrna J , Dudas Marvin J , McGill William B , Murphy Sean M 
Published: March 2010

Abstract
The sorptive behavior of two surfactants (Triton X-1000® and Dowfax® 8390) with two surface soil samples, a subsurface soil sample, a weathered black shale containing large amounts of aged organic matter, an aeolian sand, and two clay minerals (montmorillonite and kaolinite) was examined. Dowfax 8390 (dianionic surfactant) sorption was not detected with any of the samples. In contrast, Triton X-100, an ethoxylated nonionic surfactant, sorbed to all the samples. The mole surfactant sorbed/g sorbent (mol surf g sorbent) was greater for samples containing large amounts of smectite minerals and nonlinearity of the Triton X-100 isotherm increased in samples low in organic carbon. The X-ray diffraction analysis concluded that the ethoxylate group of Triton X-100 intercalates with montmorillonite. The weathered black shale sample also has a high mol surf g sorbent value when reacted with Triton X-100 but contains less smectite clay. We suggest that Triton X-100 may be reacting via hydrophobic groups (branched alkyl chain) with the shale sample. Consequently, sorption of alcohol ethoxylate surfactants cannot be predicted solely on the basis of soil attributes such as clay or organic matter content, for it appears that the organic matter-clay organization may predominate in these types of interactions.