bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation of tetraethyllead during the degradation of leaded gasoline hydrocarbons in soil
Authors: Mulroy Patrick T , Ou Li-Tse 
Published: March 2010

Abstract
For over 50 years, leaded gasoline was the only fuel for automobiles, and tetraethyllead (TEL) was the major octane number enhancer used in leaded gasoline. Ample information is available on the fate and remediation of gasoline hydrocarbons in contaminated subsoils and groundwater. However, little is known regarding the fate of TEL in leaded gasoline-contaminated subsoils and groundwater. In soil not contaminated with gasoline, TEL was rapidly degraded and completely disappeared in 14 d. In gasoline-contaminated soil, TEL degradation was slower; after 77 d, 4 to 17% of the applied TEL still remained in the contaminated soil. Disappearance of total petroleum hydrocarbons (TPH) was initially rapid but slowed appreciably after 7 to 14 d. As a result, after 77 d, 33 to 51% of the applied gasoline still remained in soil. The retardation of TEL degradation in leaded gasoline-contaminated soil is due to the presence of gasoline hydrocarbons. As long as gasoline hydrocarbons remain in soil, TEL may also remain in soil, most likely in the gasoline hydrocarbon phase.
Interference in fluorometric hydrogen peroxide determination using scopoletin–horseradish peroxidase
Authors: Donahue William F 
Published: March 2010

Abstract
Interference in fluorometric hydrogen peroxide (H2O2) determinations was investigated and attributed to exposure of the fluorophore scopoletin to visible light before the determination sequence. The combination of photobleaching and complex fluorometric properties of scopoletin results in unpredictable changes in its fluorescence unless the scopoletin is shielded from all excitation wavelengths for at least 3 min before determination. Addition of the enzyme horseradish peroxidase (HRP) to scopoletin solutions also causes dramatic decreases in solution fluorescence in the absence of H2O2. Use of a series of standard solutions of scopoletin, HRP, and H2O2 that are shielded for 3 min before independent measurement of fluorescence is suggested for calibration to eliminate these problems in determination of nanomolar concentrations of H2O2.
Lipid methodology and pollutant normalization relationships for neutral nonpolar organic pollutants
Authors: Randall Robert C , Young David R , Lee Henry , Echols Scott F 
Published: March 2010

Abstract
This work compares the ability of hexane and chloroform with methanol (C/M) to extract lipid, polychlorinated biphenyls (PCBs), and p,p′-DDE from white croaker (Geneonus lineatus) muscle tissue. Hexane extracted on average 25% of the lipid and 73% of the PCB congeners that were extracted by C/M. Both solvents extracted similar quantities of p,p′-DDE. Consequently, PCB and p,p′-DDE lipid-normalized concentrations using hexane values were 2.9 and 3.9 times greater than with C/M values, and greater than fivefold differences are possible using hexane lipid values with C/M pollutant values. Because the solvents primarily extract different lipid pools, the results conceivably approximate the largest lipid-normalized pollutant concentration differences obtainable using common solvents. The differences suggest that lipid-normalized pollutant concentrations in fish muscle tissue will vary among studies without a standardized total lipid method, but more research is required to better identify complex neutral pollutant and lipid relationships before a final standard methodology can be selected. In the interim, we recommend that the Bligh-Dyer method with C/M be used to obtain total lipid for lipid-normalizing pollutant concentrations. If another solvent or system is used, the C/M extraction should be conducted on representative samples to allow for interconversion of lipid results.
Distribution, sources, and stability of haloacetic acids in Tokyo Bay, Japan
Authors: Hashimoto Shinya , Azuma Tadashi , Otsuki Akira 
Published: March 2010

Abstract
The distribution and sources of haloacetic acids in seawater in the vicinity of Tokyo Bay, Japan, were investigated, in view of the potential toxicity of these compounds to aquatic organisms. Haloacetic acids were extracted from water samples collected at 66 sampling stations (n = 122). Concentrations of all nine haloacetic acids containing bromine and chlorine were determined by liquid chromatography–mass spectrometry. We found that concentrations of trichloroacetic acid (TCAA) were high (maximum: 20.3 μg/L) compared to those of the other haloacetic acids in coastal seawater. The distributions and relative concentrations of TCAA and other haloacetic acids (monochloroacetic acid, dichloroacetic acid, and bromochloroacetic acid) suggest that their sources are not identical; discharge of wastewaters containing TCAA in the bay area is probably one of the main sources of the observed high concentrations of TCAA in seawater there. The mean concentrations of haloacetic acids in water samples and the results of incubation experiments of haloacetic acids in river water and seawater suggest that TCAA is relatively stable in the aquatic environment.
Distribution of uranium-238 in environmental samples from a residential area impacted by mining and milling activities
Authors: McConnell Marc A , Ramanujam V M Sadagopa , Alcock Nancy W , Gabehart Gary J , Au William W 
Published: March 2010

Abstract
The northern region of Karnes County, Texas, USA, has been the site of extensive mining/milling of uranium for over 30 years. A previous study in our laboratory indicates that residents living near these facilities have increased chromosomal aberrations and a reduced DNA repair capacity. In this study, the long-lived radionuclides uranium-238 (238U) and thorium-232 (232Th) were measured in order to evaluate the extent of contamination from mining/milling facilities. 232Th was quantified simultaneously and served as a reference. Soil samples (n = 70) were collected from the yards of previously studied households and adjacent areas near former mining and mining/milling sites at the surface and 30 cm subsurface. Additionally, samples from drinking water wells (n = 6) were collected from selected households. Sites located over 14 km from the study area with no known history of mining/milling served as the control. In the control area, 238U concentrations in soil were consistent between surface (0.13–0.26 mg/kg) and subsurface (0.13–0.23 mg/kg) samples. Near mining/milling sites, 238U in surface soil (0.34–15.71 mg/kg) was found to be consistently and statistically higher (p &lt; 0.05) than corresponding subsurface samples (0.17–2.11 mg/kg). Near mining-only areas, 238U in surface soil (1.11–1.97 mg/kg), however, was not significantly increased over subsurface soil (0.96–1.68 mg/kg). As expected, 238U was much higher overall in the mining/milling and mining-only areas compared to the control sites. No trends were detected in the distribution of 232Th. The concentration of 238U was up to six times higher in a drinking water well near a former mining/milling operation, indicating possible leaching into the groundwater, while 232Th concentrations were low and uniform. Furthermore, lead isotope ratio analysis indicates contamination from the interstate shipping of ore by rail to and from a mining/milling facility. These data indicate contamination of the environment by the mining/milling activities in a residential area.
Concomitant aerobic biodegradation of benzene and thiophene
Authors: Dyreborg Søren , Arvin Erik , Broholm Kim 
Published: March 2010

Abstract
The concomitant aerobic biodegradation of benzene and thiophene was investigated in microcosm experiments using a groundwater enrichment culture. Benzene was biodegraded within 1 d, whereas thiophene could not be biodegraded as the sole source of carbon and energy. Some interesting phenomena were observed when both benzene and thiophene were present. In most cases, removal of thiophene was observed, and the removal occurred concomitantly with the biodegradation of benzene, suggesting that benzene was used as a primary substrate in the cometabolic biodegradation of thiophene. No biodegradation of the two compounds was observed for some combinations of concentrations, suggesting that thiophene could act as an inhibitor to benzene biodegradation. However, this effect could be overcome if more benzene was added to the microcosm. Residual concentrations of benzene and thiophene were observed in some microcosms and the data indicated that the biodegradation of the two compounds stopped when a critical threshold ratio between the concentrations of thiophene and benzene was reached. This ratio varied between 10 and 20. Results from modeling the biodegradation data suggested that thiophene was cometabolized concomitantly with the biodegradation of benzene and that the biodegradation may be described by a modified model based on a traditional model with an inhibition term incorporated.
Changes in metallothionein mRNA and protein after sublethal exposure to arsenite and cadmium chloride in juvenile winter flounder
Authors: Jessen-Eller Kathy , Crivello Joseph F 
Published: March 2010

Abstract
Juvenile winter flounder (Pleuronectes americanus) from a Long Island Sound site within the Niantic River region contain elevated levels of liver As and Cd. Previous work in mammals suggests that a reduced species of As, NaAs3+, is as potent a metallothionein (MT) inducer as CdCl2. We investigated whether this is also the case in winter flounder by subcutaneously exposing juveniles to a sublethal range of NaAs3+ (0, 0.38, 0.75, and 1.5 μmol/g fish) or CdCl2 (0, 0.045, 0.09, and 0.18 μmol/g fish). Of the two, CdCl2 was the more potent MT inducer, with an 8-fold lower molar equivalent causing a 3-fold higher response. Both metals rapidly induced MT protein within 24 h of exposure, but only the highest dose of CdCl2 elicited a significant increase in MT mRNA. The magnitude of the MT protein response to CdCl2 (7.25-fold) demonstrates that elevated liver As and Cd do not narrow the MT response window in juvenile flounder from the Niantic River region. These fish have relatively low liver MT protein levels (46 μg/g) and will be a useful reference population for future metal impact studies within Long Island Sound.
Combined effects of copper, desiccation, and frost on the viability of earthworm cocoons
Authors: Holmstrup Martin , Petersen Birgitte Friis , Larsen Martin Mørk 
Published: March 2010

Abstract
The effects of heavy metal pollution on earthworms have been extensively studied, but no studies have examined how earthworms react if they are simultaneously exposed to metal pollution and climatic stress. This question has been addressed in a laboratory study where cocoons of Aporrectodea caliginosa and Dendrobaena octaedra were initially exposed to copper in aqueous solutions of copper chloride and thereafter exposed to realistic degrees of either desiccation or frost. Earthworm embryos absorbed copper in amounts (up to approx. 200 mg/kg dry tissue weight) comparable to concentrations found in various tissues of earthworms from metal-polluted soils. Desiccation and copper exposure in combination had synergistic effects on survival rates for both species. For example, at full saturation, the NOEC (the highest tested concentration with no statistically significant effect) for copper of A. caliginosa was 12 mg/L, whereas at 97% relative humidity it was only 6 mg/L. Frost and copper exposure in combination also showed synergistic effects in some experiments. No cocoons of A. caliginosa exposed to 20 mg copper/L were viable after exposure to −3°C but at 0°C viability was as high as 95%. The same tendency was seen in D. octaedra but not as clearly as in A. caliginosa. A change of the environmental conditions (moisture, temperature) to increasing severity caused a shift in the statistically derived NOEC toward lower critical values of copper. The involvement of combination effects in ecotoxicological tests could therefore improve risk assessment of soil-polluting compounds.
Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores
Authors: Hooten Russell L , Carr R Scott 
Published: March 2010

Abstract
An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciata zoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH3 than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH3 concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciata zoospore germination was not affected by samples with high NH3 concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH3 and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH3.
Identification of chloro-nitro-trifluoromethyl-substituted dibenzo-p-dioxins in lampricide formulations of 3-trifluoromethyl-4-nitrophenol: Assessment to induce mixed function oxidase activity
Authors: Hewitt L Mark , Carey John H , Munkittrick Kelly R , Parrott Joanne L , Solomon Keith R , Servos Mark R 
Published: March 2010

AbstractThe contamination of field formulations of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) bya dibenzo-p-dioxin containing -chloro, -nitro, and -trifluoromethyl substituents was suspected from chemical fractionations of a TFM formulation that were directed by mixed function oxidase (MFO) induction in rainbow trout. Three dioxin isomers containing these substituents in field formulations were identified by gas chromatography–mass spectrometry (GC-MS). Short-term waterborne exposures to a mixture of two isomers, 2-trifluoromethyl-3-nitro-7- (and 8)-chloro-dibenzo-p-dioxin, elevated MFO activity in trout, with a threshold between 0.148 and 0.745 nM (4.1–20.5 ng/L). Synthetic preparations of other dioxins related to formulation impurities enabled characterizations of this previously unknown family of dioxin congeners by GC-MS. The elution order of the isomers followed those established for halogenated dioxins except where there was a lone -nitro substitution on one ring. The average concentration of these compounds in TFM formulations spanning more than a decade was 288 ± 47 μg/L, which translates into an annual loading of approximately 40 g to the Great Lakes Basin. Using mammalian (H4IIE) and fish (PLHC-1) in vitro assays, a 2,3,7-substituted chloro-nitro-trifluoromethyl isomer was a four to five times more potent inducer of MFO activity than 2,3,7-trichlorodibenzo-p-dioxin. Characterizations of the synthetic isomers indicate that the isomers present in the formulation are not substituted in the 2,3,7- positions and are relatively weak inducers of MFO activity.
Bioconcentration of gaseous organic chemicals in plant leaves: Comparison of experimental data with model predictions
Authors: Polder Marieke D , Hulzebos Etje M , Jager D Tjalling 
Published: March 2010

Abstract
This literature study is performed to support the implementation of two models in a risk assessment system for the evaluation of chemicals and their risk for human health and the environment (Uniform System for the Evaluation of Substances [USES] 1.0). One of the exposure pathways for humans and cattle is the uptake of chemicals by plants. In this risk assessment system the transfer of gaseous organic substances from air to plants modeled by Riederer is included. A similar model with a more refined approach, including dilution by growth, is proposed by Trapp and Matthies, which was implemented in the European version of this risk assessment system (EUSES). In this study both models are evaluated by comparison with experimental data on leaf/air partition coefficients (bioconcentration factors [BCFs]) found in the literature. For herbaceous plants both models give good estimations for the leaf/air partition coefficient up to 107, with deviations for most substances within a factor of five. For the azalea and spruce group the fit between experimental BCF values and the calculated model values is less adequate. For substances for which Riederer estimates a leaf/air partition coefficient above 107, the approach of Trapp and Matthies seems more adequate; however, few data were available.
An inexpensive and efficient modular water-renewal system for bulk sediment toxicity testing
Authors: Leppanen Christy J , Maier Kurt J 
Published: March 2010

Abstract
Recently developed test guidance for conducting whole-sediment toxicity tests with aquatic invertebrates requires exchange of overlying water to maintain acceptable water quality. Described here is an accurate and consistent modular water-renewal system (delivering 150 ± 5 ml renewal water) and containment chamber for bulk sediment toxicity tests. The system can be customized to meet testing demands by adding multiple units. Each unit can hold up to 49 300-ml beakers. Construction is simple (&lt;4 h/unit) and inexpensive (&lt; $90/unit). This system has been used successfully in 10-d whole-sediment toxicity tests with Chironomus tentans and Hyalella azteca.
Predicting the toxicity of sediment-associated trace metals with simultaneously extracted trace metal: Acid-volatile sulfide concentrations and dry weight-normalized concentrations: A critical comparison
Authors: Long Edward R , MacDonald Donald D , Cubbage James C , Ingersoll Chris G 
Published: March 2010

AbstractThe relative abilities of sediment concentrations of simultaneously extracted trace metal: acid-volatile sulfide (SEM: AVS) and dry weight-normalized trace metals to correctly predict both toxicity and nontoxicity were compared by analysis of 77 field-collected samples. Relative to the SEM:AVS concentrations, sediment guidelines based upon dry weight-normalized concentrations were equally or slightly more accurate in predicting both nontoxic and toxic results in laboratory tests.
Estimating impact of humic acid on bioavailability and bioaccumulation of hydrophobic chemicals in guppies using kinetic solid-phase extraction
Authors: Freidig Andreas P , Garicano Elsa Artola , Busser Frans J M , Hermens Joop L M 
Published: March 2010

AbstractMany organic micropollutants show a reduced bioavailability in the presence of dissolved organic matter, which is explained by reduction of the freely dissolved aqueous concentration. The partition coefficient between organic matter and the aqueous phase, KDOC, is used to describe the distribution of neutral hydrophobic micropollutants. In the present study, the freely dissolved concentration was measured using partitioning of micropollutants between water and a hydrophobic solid-phase filter disk (C-18 Empore™ disk). Slivers of the disk were exposed in aqueous solutions that contained several micropollutants and Aldrich humic acid at different concentrations. Initial uptake rates of the micropollutants from water to disk (k1) were measured to estimate the freely dissolved concentration in the solution. Partition coefficients, KDOC, of tetra- and hexachlorobenzene, pentachloroaniline, iodofenphos, and p,p′ DDT were calculated. These values were comparable to earlier, published KDOCs toward Aldrich humic acid. In a validation experiment, the uptake rates of three chlorobenzenes in guppy (Poecilia reticulata) were measured in the absence and presence of humic acids. The lowering of the uptake rates in guppy was correctly predicted with the KDOC values from the Empore disk experiment. These findings suggest that the proposed method to measure the freely dissolved concentration is a valid tool to predict the bioavailability of hydrophobic compounds in the aqueous environment.
Application of toxicity-based fractionation techniques and structure-activity relationship models for the identification of phototoxic polycyclic aromatic hydrocarbons in sediment pore water
Authors: Kosian Patricia A , Makynen Elizabeth A , Monson Philip D , Mount David R , Spacie Ann , Mekenyan Ovanes G , Ankley Gerald T 
Published: March 2010

AbstractRecent studies conducted at our laboratory have shown that sediments contaminated with complex mixtures of polycyclic aromatic hydrocarbons (PAHs) can exhibit enhanced toxicity (lethality) to a variety of aquatic species when the samples are tested under ultraviolet (UV) light designed to mimic the wavelengths present in sunlight. However, because these contaminated sediments can contain literally thousands of chemicals, it is difficult to use conventional analytical techniques to identify those compounds responsible for photo-induced toxicity. The purpose of this study was to adapt existing toxicity identification evaluation methods to attempt to identify those compounds contributing to the phototoxicity observed in our sediment samples. Pore water obtained from sediments collected near an oil refinery discharge was toxic to Lumbriculus variegatus following exposure to UV light, while organisms exposed to the same pore water, but without subsequent UV treatment, showed no toxic effect. Solid-phase extraction disks and high-performance liquid chromatography were used, in conjunction with toxicity tests with L. variegatus, to extract and fractionate phototoxic chemicals from the pore water. Phototoxic fractions analyzed by gas chromatography–mass spectrometry revealed the presence of a number of aliphatic hydrocarbons, substituted PAHs, and PAHs containing heteroatoms. Chemicals were screened for their phototoxic potential based on empirical data and predictive models. A refined list of PAHs was then evaluated on the basis of their phototoxic potency as defined by a recently developed quantitative structure–activity relationship model and estimates of their bioaccumulation potential. Based on the model predictions of potency and bioaccumulation, nine likely phototoxic chemicals were identified.
Use of a lux-modified bacterial biosensor to identify constraints to bioremediation of btex-contaminated sites
Authors: Sousa Sofia , Duffy Catherine , Weitz Hedda , Glover L Anne , Bär Eckart , Henkler Rolf , Killham Ken 
Published: March 2010

Abstract
Sediment and groundwater samples obtained from a benzene, toluene, ethylbenzene, and xylene (BTEX)-contaminated site were screened, using a bioluminescence-based (lux gene-marked) bacterial biosensor, to identify constraints to site remediation. Through a series of sample manipulations and linked biosensor responses, constraints to BTEX remediation such as adverse pH, presence of nonvolatile organic contaminants, and the presence of heavy metals were investigated. Conventional chemical analysis (gas chromatography, inductively coupled plasma mass spectroscopy) was used to confirm the reliable performance of the biosensor and to identify its potential contribution to site management to ensure effective remediation. The toxicity results of the biosensor were expressed in % maximum bioluminescence calculated against a blank of double deionized water with pH adjusted to 5.5. Untreated samples caused reductions in percentage bioluminescence from 10 to 95%. Water sample W1, containing a total BTEX concentration of 30,595 μg/L caused the highest decrease in bioluminescence (5.78%). This toxicity was significantly reduced after elimination of volatile organic compounds (VOCs) (42.01%) and bioluminescence was further increased to 87.80% after removal of total organic matter. This suggested that VOCs were not the only toxic organopollutants present. Water samples giving high values of bioluminescence contained BTEX concentrations of 17 to 31 μg/L.