bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chlorinated hydrocarbons in flatfishes from the Southern California, USA, Bight
Authors: Schiff Kenneth , Allen M James 
Published: March 2010

Abstract
Alhough inputs of chlorinated hydrocarbon compounds to the Southern California Bight (SCB) are presently low, historical deposits represent a source of bioaccumulation potential to sediment-associated fauna. To assess this bioaccumulation potential, 14 chlorinated hydrocarbon classes were measured in livers of three species of flatfish collected from 63 randomly selected sites on the coastal shelf between Point Conception and the United States–Mexico international border. Tissue contamination was widespread throughout the SCB, but was limited to just two chlorinated hydrocarbon classes. Virtually 100% of Pacific sanddab (Citharichthys sordidus) and longfin sanddab (Citharichthys xanthostigma) populations were estimated to be contaminated with dichlorodiphenyltrichloroethane (total DDT = sum of o,p′ and p,p′ isomers of DDT + dichlorodiphenyldichloroethylene [DDE] + dichlorodiphenyldichloroethane [DDD]) and/or polychlorinated biphenyls (total PCBs). Total DDT also contaminated the majority (64%) of the Dover sole (Microstomus pacificus) population in the SCB. Total PCB measurements in tissues of SCB flatfish were dominated by 12 congeners (52, 66, 87, 101, 105, 118, 128, 138, 153, 170, 180, and 187), which averaged 95% of the combined mass of the 27 congeners analyzed. Sediment concentrations (normalized by total organic carbon content) accounted for most of the variability observed in tissue concentrations (normalized by lipid content) for 8 of these 12 congeners and total PCBs. Normalized sediment concentrations were also significantly correlated to normalized tissue concentrations for total DDT and p,p′-DDE. Tissue concentrations measured in this study from reference areas of the SCB were compared to tissue concentrations measured from reference areas in studies conducted in 1977 and 1985. Total DDT and total PCB liver concentrations were found to have decreased one to two orders of magnitude in Pacific and longfin sanddabs between 1985 and 1994. Total DDT and total PCB liver concentrations decreased 5- to 35-fold in Dover sole between 1977 and 1994.
An in vitro assessment of the toxicity of 2,4-dichloroaniline using rainbow trout primary epidermal cell cultures
Authors: Kilemade Michael , Mothersill Carmel 
Published: March 2010

Abstract
2,4-Dichloroaniline (2,4-DCA) is a common pollutant of freshwaters. Information on the effects of this chemical on the aquatic environment is lacking. In this work, we present a technique using primary cell culture of rainbow trout (Oncorhynchus mykiss) epidermal cells as a model for the evaluation of the potential ecotoxicologic hazards of 2,4-DCA. The effects of a wide dose range of the chemical on survival and function of the cells were studied. 2,4-Dichloroaniline was found to show an increasingly toxic effect over the dose range of 100 to 1,000 μM. The toxicity threshold was observed to occur at approximately 400 μM in serum-containing media and 200 μM in serum-free media. The LC50 in serum-containing media at 24, 48, 72, and 96 h of exposure ranged from 650 to 740 μM. In serum-free media the LC50 ranged from 340 to 500 μM over a similar time period. Therefore, the toxicity of 2,4-DCA to the primary cells increased in the absence of serum in the culture medium. As the 2,4-DCA concentration increased the number of goblet (mucus) cells present in the cultures decreased, as did the normal healthy epidermal cells. Cell death was predominantly necrotic as opposed to apoptotic. This study is the first demonstration of an in vitro technique using fish primary epidermal cultures as a toxicology assessment tool. The major advantage of using primary cultures as opposed to immortalized cell lines is in the ability of these cultures to maintain their in vivo characteristics for approximately 10 d postexposure, allowing the study of the acute effects of aquatic contaminants. The characteristics of established cells deviate substantially from those of normal cells.
Toward a mechanistic understanding of contaminant-induced changes in detritus processing in streams: Direct and indirect effects on detritivore feeding
Authors: Forrow David M , Maltby Lorraine 
Published: March 2010

AbstractMacroinvertebrate feeding is a major rate-limiting step in the processing of detritus in streams. Environmental contaminants can reduce detritus processing by decreasing the abundance or feeding activity of detritivores. Contaminant-induced reductions in detritus processing can have important consequences for the structure and functioning of the stream community. Here we investigate the mechanistic basis for reduced leaf processing in a stream contaminated with motorway (superhighway) runoff. In situ and laboratory studies were used and the work focused on Gammarus pulex (Amphipoda), the dominant detritivore at the site. The in situ feeding rate of G. pulex was significantly reduced downstream of the motorway discharge. Reductions in feeding rate could be the result of contaminants in the discharge having a direct effect on the animal or the discharge may affect the animal's feeding indirectly, by reducing food quality. Food quality may be reduced by contaminant accumulation or changes in microbial conditioning. Laboratory studies demonstrated that the main mechanism responsible for the reduction in feeding was direct toxicity and that this was most severe when animals were in direct contact with contaminated sediments. Neither contaminant accumulation nor differences in microbial conditioning affected the choice or consumption of leaf material by G. pulex over short exposure periods (i.e., &lt; 14 d). However, contaminant-induced reductions in microbial conditioning were important over longer exposure periods (i.e., ≥27 d).
Estimating and testing bioconcentration factors
Authors: Bailer A John , Walker Sean E , Venis Kyle J 
Published: March 2010

Abstract
Bioconcentration factors (BCFs) are commonly calculated to represent the equilibrium concentration of a substance in an organism relative to environmental concentrations of the same substance. The BCF is derived from parameters estimated in uptake and elimination experiments and is presented as a single value without error estimates or confidence intervals. However, it is desirable to know the variability/precision of the BCF estimate and to statistically compare BCFs among experimental conditions. In this study, the calculation of standard errors and confidence intervals for BCFs is presented. In addition, a statistical method for formally comparing the BCFs derived under two or more experimental conditions is discussed. These methods are illustrated using data from a study of DDT-exposed Hyalella azteca and Diporeia spp.
Developing a standard spiking procedure for the introduction of hydrophobic organic compounds into field-wet soil
Authors: Northcott Grant L , Jones Kevin C 
Published: March 2010

AbstractThe purpose of this study was to reevaluate a number of spiking procedures we had previously investigated for spiking dry soil, determine their suitability for spiking radiolabeled hydrophobic organic compounds in field-wet soil, and identify the optimal spiking procedure. In the first part of this study, two radiolabeled polycyclic aromatic hydrocarbons (PAHs), phenanthrene (Phe) and benzo[a]pyrene (BaP), were introduced into field-wet soil by four different spiking procedures and the recovery and homogeneity of compound distribution assessed by analysis of replicate subsamples. The identified optimal spiking procedure involved adding an acetone spike solution to 10 ml acetone in a blender base, adding 250 g field-wet soil, and mixing with a highspeed blender. The relative standard deviations obtained by this procedure were 2.7 and 5.3% for 14C-Phe and 14C-7-BαP, respectively, and were comparable to those we obtained in a previous study for spiking dry soil. The persistence of acetone used as a carrier solvent in the optimal spiking procedure was assessed at various times after spiking to identify a suitable equilibration time to allow for solvent volatilization. The equilibration time, together with the identified optimal spiking procedure, were combined to develop a standard spiking procedure. The standard spiking procedure was used to prepare multiple soil microcosms individually spiked with radiolabeled Phe, pyrene, and BaP for a long-term aging study on the formation of PAH-bound residues in arable soil. The mean spike activity and homogeneity of spike distribution in 54 sterilized microcosms (3 × 18) stored over 525 d was determined. Mean spike recovery and relative standard deviations (RSDs) for the three radiolabeled PAHs in the individually spiked and prepared microcosms were very good. However, this data illustrates the importance of determining the concentration and homogeneity of spikes within all individual test portions in experiments where organic compounds are spiked into soil or sediment.
Oral deformities in several species of frogs from the Savannah River Site, USA
Authors: Burger Joanna , Snodgrass Joel W 
Published: March 2010

AbstractTadpoles of seven species of frogs from 22 wetlands on the Savannah River Site in South Carolina, USA, were examined to assess the prevalence of mouth-part deformities and axial skeletal deformities. Species examined included southern toad (Bufo terrestris), pine woods treefrog (Hyla femoralis), spring peeper (Pseudacris crucifer), southern chorus frog (P. nigrita), ornate chorus frog (P. ornata), bronze frog (Rana clamitans), and southern leopard frog (R. utricularia). Of the 4,335 tadpoles examined in 1997 and 1998, 6% exhibited mouth-part deformities and none exhibited axial skeletal deformities. However, significant interspecific differences existed for both prehind-limb and posthind-limb developmental stages. The highest percentage of deformities in prehind-limb stage occurred in spring peeper (27%), ornate chorus frog (29%), and bronze frog (33%), and the lowest percentage occurred in southern toad (5.5%) and southern chorus frog (4.8%). The frequency of mouth deformities decreased from the prehind-to posthind-limb developmental stage for six of seven species and was significant for southern toad and ornate chorus frog. Differences existed in the percent of mouth-part deformities among species in the same wetland and among wetlands for two species (southern toad and southern leopard frog). Among southern toads, mouth-part deformities increased with increasing hydroperiod length. Oral deformities may lead to lowered feeding success and lowered survival of tadpoles, resulting in a lower percentage of deformities in the posthind-limb stage.
Analysis of estrogenic hormones in municipal wastewater effluent and surface water using enzyme-linked immunosorbent assay and gas chromatography/tandem mass spectrometry
Authors: Huang Ching-Hua , Sedlak David L 
Published: March 2010

Abstract
Ahough the estrogenichormones177β-estradiol and 17α-ethinyl estradiol can be quantified in polluted waters by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/tandem mass spectrometry (GC/MS/MS), the compounds often are present at concentrations below detection limits. Enzyme-linked immunosorbent assays (ELISAs) provide a sensitive and robust means of quantifying estrogenic hormones in wastewater effluents and surface waters. Results from ELISA analysis of estrogenic hormones in secondary wastewater effluent indicate concentrations comparable to those that cause vitellogenesis in fish. Confirmatory analyses by GC/MS/MS are consistent with ELISA results. Effluent filtration, using sand filtration or microfiltration, removes approx. 70% of the hormones from secondary effluent, while advanced treatment, using reverse osmosis, removes more than 95% of hormones. The detection limits for estrogenic hormones are approx. 0.1 ng/L in wastewater effluent and 0.05 ng/L in surface water. The ELISA technique provides a relatively simple and practical method of assessing the fate of estrogenic hormones in engineered and natural systems.
Developmental stage-specific life-cycle bioassay for assessment of sediment-associated toxicant effects on benthic copepod production
Authors: Chandler G Thomas , Green Andrew S 
Published: March 2010

Abstract
In chronic bioassays of sediment organic compounds, toxicant exposures often decline through time, such that the beginning of a test yields disproportionately higher exposures than the end. Thus, those life stages initiating a test often are exposed to the highest concentrations, and for rapidly maturing test fauna, this may lead to varying conclusions regarding compound toxicities depending on the initial life stage chosen. This problem can be addressed by comparative full life-cycle tests initiated with different test-organism life stages. Thus, a full life stage-to-life stage toxicity test was developed for the rapidly maturing meiobenthic copepod Amphiascus tenuiremis to assess the importance of developmental stage at the onset of sediment toxicant exposure relative to reproduction, net population growth, and sex and age structure. Tests were conducted with a model spiked-sediment insecticide, chlorpyrifos, for each of the major life stages (P1) of A. tenuiremis (nauplius, copepodite, and adult). Each P1 stage was allowed to mature and reproduce in low chlorpyrifos concentrations (6–33% of stage-specific 96-h LC50s; 4–22 ng chlorpyrifos/g dry sediment) for 26 d. Test endpoints were numbers of surviving adult females, males, eggs per female (clutch), first generation (F1) nauplii, F1 copepodites, F1 total production, and realized F1 production per surviving female. Only the copepodite P1 test showed a significant decline in survival of an adult age class: females declined by 28% at 22 ng/g. Reductions in total production ranged from 33–96% of controls from nauplius to adult. The P1 naupliar stage was most sensitive, with F1 production being 33–47% of that in controls. However, on a realized production per female basis, both the copepodite and naupliar P1 yielded significantly reduced F1S of 23 and 40% of controls at 11 and 22 ng/g.
Potential multidrug resistance gene POHL: An ecologically relevant indicator in marine sponges
Authors: Krasko Anatoli , Kurelec Branko , Batel Renato , Müller Isabel M , Müller Werner E G 
Published: March 2010

Abstract
Sponges are sessile filter feeders found in all aquatic habitats from the tropics to the arctic. Against potential environmental hazards, they are provided with efficient defense systems, e.g., protecting chaperones and/or the P-170/multidrug resistance pump system. Here we report on a further multidrug resistance pathway that is related to the pad one homologue (POH1) mechanism recently identified in humans. It is suggested that proteolysis is involved in the inactivation of xenobiotics by the POH1 system. Two cDNAs were cloned, one from the demosponge Geodia cydoniumand a second from the hexactinellid sponge Aphrocallistes vastus. The cDNA from G. cydonium, termed GCPOHL, encodes a deduced polypeptide with a size of 34,591 Da and that from A. vastus, AVPOHL, a protein of a calculated Mr of 34,282. The two sponge cDNAs are highly similar to each other as well as to the known sequences from fungi (Schizosaccharomyces pombe and Saccharomyces cerevisiae) and other Metazoa (from Schistosoma mansoni to humans). Under controlled laboratory conditions, the expression of the potential multidrug resistance gene POHL is, in G. cydonium, strongly upregulated in response to the toxins staurosporin (20 μM) or taxol (50 μM); the first detectable transcripts appear after 1 d and reach a maximum after 3 to 5 d of incubation. The relevance of the expression pattern of the G. cydonium gene POHL for the assessment of pollution in the field was determined at differently polluted sites in the area around Rovinj (Croatia; Mediterranean Sea, Adriatic Sea). The load of the selected sites was assessed by measuring the potency of XAD-7 concentrates of water samples taken from those places to induce the level of benzo[a]pyrene monooxygenase (BaPMO) in fish and to impair the multidrug resistance (MDR)/P-170 extrusion pump in clams. These field experiments revealed that the levels of inducible BaPMO activity in fish and of the MDR potential by the water concentrates are highly correlated with the level of expression of the potential multidrug resistance gene POHL in G. cydonium. This report demonstrates that the detoxification POH pathway, here mediated by the G. cydonium GCPOHL gene, is an additional marker for the assessment of the environmental load in a given marine area.
Stability of immobilized 2,4,6-trinitrotoluene metabolites in soil under long-term leaching conditions
Authors: Achtnich Christof , Lenke Hiltrud 
Published: March 2010

Abstract
2,4,6-Trinitrotoluene (TNT)-contaminated soil was remediated by an anaerobic/aerobic slurry process. Prior to treatment, the soil was spiked with [14C]-TNT. Leaching experiments were carried out with the decontaminated soil to determine the degree of binding of the radiolabel under a variety of conditions. To simulate natural degradation processes of soil organic matter, each of three columns was subjected to a different treatment known to enhance biological transformation over a 92-week period. Only minor amounts of radioactivity (1.0% of the bound radioactivity) were released from treated soil incubated in the presence of the lignin-degrading fungus Phanerochaete chrysosporium. Simulation of seasonal variation in temperature, including freezing of the soil, did not cause a significant release of radioactivity (1.4%). Growth and flowering of the bush bean Phaseolus vulgaris only released 0.8% of the bound radioactivity to the eluate; however, during the decomposition phase, an additional 7.7% of the bound radioactivity was released. We propose that this radioactivity was bound to soluble humic material that was mobilized due to a pH shift during the decomposition of the plant organic matter. This is supported by the observation that neither free TNT nor its metabolites were present in the eluate. During the different incubation experiments, 3.9 to 8.5% of the bound radioactivity was found as 14CO2. The results indicate a slow turnover of even strongly bound immobilized metabolites of TNT.
The fungicide propiconazole interferes with embryonic development of the crustacean Daphnia magna
Authors: Kast-Hutcheson Karen , Rider Cynthia V , LeBlanc Gerald A 
Published: March 2010

Abstract
Propiconazole is a fungicide used in a variety of agricultural applications. Preliminary studies had suggested that embryos of the crustacean Daphnia magna are particularly susceptible to the toxicity of this chemical. The goals of the present study were to define endpoints of daphnid embryonic development that could be routinely used to assess the embryo toxicity of chemicals and to characterize definitively the embryo toxicity of propiconazole to daphnids. Daphnid embryonic development was characterized into six readily distinguishable stages based on the degree of tissue differentiation. Embryonic development could be monitored either in the brood chamber of the maternal organism or using embryos removed from the brood chamber and incubated ex vivo. Standard toxicity assessment revealed that propiconazole elicited no significant adverse effects on daphnid survival or fecundity during a 21-d exposure to concentrations as high as 0.25 mg/L. Exposure to 0.25 mg/L propiconazole, however, caused a significant incidence of developmental abnormalities and embryonic death. Abnormalities were consistent with developmental arrest at later stages of embryonic maturation. Propiconazole elicited a steep concentration-response curve with respect to embryo toxicity, with a 10% and a 90% incidence of embryo toxicity measured at 0.50 and 0.82 mg/L, respectively. Direct exposure of embryos to propiconazole resulted in toxicity, though the incidence and characteristics of developmental abnormalities were not consistent with that observed during chronic exposures. However, maternal exposure to propiconazole followed by transfer of early embryos to propiconazole-free media resulted in embryo toxicity consistent with that observed during chronic exposure. These results indicate that propiconazole interferes with the later stages of daphnid embryonic development, and that this toxicity is manifested largely via maternal exposure to the fungicide.
Occurrence and potential adverse effects of semivolatile organic compounds in streambed sediment, United States, 1992–1995
Authors: Lopes Thomas J , Furlong Edward T 
Published: March 2010

Abstract
The occurrence and potential adverse effects of select semivolatile organic compounds (SVOCs) in streambed sediment were assessed at 536 sites in 20 major river basins across the United States from 1992 to 1995. Fifty-six SVOCs were detected at one or more sites, and one or more SVOCs were detected at 71% of sites. The northeastern and Great Lakes regions and large metropolitan areas have the highest SVOC concentrations. Polycyclic aromatic hydrocarbons (PAHs) were detected most frequently and at the highest concentrations. Concentrations of PAHs and phthalates were about 10 times higher at sites influenced by urban activities than at sites in other land-use areas. Semivolatile organic compounds were significantly (α = 0.05) correlated with land use and population density, and PAHs also correlated with physical/chemical properties. On the basis of sediment-quality guidelines, adverse effects are probable at 7.5% and possible at 16.2% of the sites. Most of the potential for adverse effects is due to PAHs. The median percentage of urban land use was 8% at sites with possible adverse effects and 16% at sites with probable adverse effects. Urbanization profoundly affects sediment quality, even though it comprised a small percentage of most drainage basins.
Polychaete indicator species as a source of natural halogenated organic compounds in marine sediments
Authors: Fielman Kevin T , Woodin Sarah A , Lincoln David E 
Published: March 2010

Abstract
Studies of pollutant impact on the marine environment assume that organic contaminants are anthropogenic in origin. However, many common polychaete worms and sediments contain readily detectable concentrations of brominated natural products that are often analogues of chlorinated anthropogenic contaminants. Both polychaetes and sediments are used extensively in environmental toxicology and monitoring, and the extent to which natural halometabolites may confound these studies is unknown. To characterize further the relationship among infauna, indicator species, and sedimentary halogenated organics, we examined sediments and infauna from a pristine habitat and animals maintained under laboratory culture for haloorganics using gas chro-matography/mass spectrometry. Natural haloorganics are a consistent feature of pristine marine soft-bottom habitats, and their spatial and temporal variation correlates with the abundance of infauna that produce these metabolites. Abundant organohalogens are also present in the widespread polychaete indicator species Capitella sp. I and Streblospio benedicti but absent from the marine invertebrate toxicology model Neanthes arenaceodentata. Studies from the individual to the community level within the fields of ecology, toxicology, and environmental chemistry could be readily confounded by failing to consider these novel animal and habitat characteristics.