bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overview and comparison of lipid-containing semipermeable membrane devices and oysters (Crassostrea gigas) for assessing organic chemical exposure
Authors: Huckins James N. , Prest Harry F. , Petty Jimmie D. , Lebo Jon A. , Hodgins Maureen M. , Clark Randal C. , Alvarez David A. , Gala William R. , Steen Alexis , Gale Robert , Ingersoll Christopher G. 
Published: November 2004

Abstract
We performed 20-d, flow-through exposures of lipid-containing semipermeable membrane devices (SPMDs) and Pacific oysters (Crassostrea gigas) to three concentrations (nominally 10, 100, and 250 ng/L) of a diverse mixture of polycyclic aromatic hydrocarbons (PAHs). Exposure water was seawater free of particulates larger than 0.1 μm. The results of these controlled laboratory studies demonstrated that SPMDs and oysters concentrate the same chemicals but that the relative amounts accumulated are different. For oysters, the 20-d mean (across treatments) concentration factors (CFs) of test compounds with log Kow ≤ 4.8 were much lower (4.0- to 20-fold lower) than those of the same compounds in SPMDs. In contrast, the 20-d CFs of PAHs with log Kow ≥ 5.6 in oysters from the low-level treatment were higher than the corresponding CFs for SPMDs. The CFs of these compounds in oysters from the low-level treatment ranged from approximately 3.0- to 13-fold higher than those in oysters from the high-level treatment. This physiologically mediated difference in oyster CFs appears to be linked to active feeding in the low-level treatment and to apparent toxicity-induced cessation of feeding (i.e., valve closure) in the high-level treatment. Because CFs for these compounds in oysters were not independent of exposure concentrations, it follows that tissue levels were not proportional to exposure concentration. However, both sampling approaches have advantages and disadvantages, and the appropriateness of their use depends on the goals of a given study.
Effects of vertebrate hormones on development and sex determination in Daphnia magna
Authors: Kashian Donna R. , Dodson Stanley I. 
Published: November 2004

Abstract
Daphnia (Crustacea) are extensively used as model organisms in ecotoxicology; however, little is known regarding their endocrine system. This study examines Daphnia vulnerability to vertebrate hormones. Twelve natural or synthetic vertebrate hormones were screened for activity on developmental and reproductive processes in Daphnia magna. Natural hormones tested included: β-estradiol, gonadotropin, hydrocortisone, insulin, melatonin, progesterone, somatostatin, testosterone, and thyroxine at concentrations ranging from 1 to 100 μg/L. Synthetic hormones tested included diethylstilbestrol (estrogenic), R-1881 (androgen), and ICI-182,780 (antiestrogen); all hormones were screened with a 6-d assay. Additionally, progesterone, insulin, testosterone, and thyroxine were screened for 25 d. Diethylstilbestrol decreased D. magna growth rate while thyroxine increased it. Short-term testosterone exposure reduced D. magna fecundity; however, long-term exposure did not, potentially indicating testosterone hydroxylation with long-term exposure. Hormones commonly considered sex-hormones (estrogens and androgens) in vertebrates do not appear to control sexual differentiation in D. magna; however, several vertebrate hormones do affect reproduction and development in D. magna making D. magna a potentially useful tool in monitoring for the presence of these hormones or compounds that mimic them.
The long-term fate of polychlorinated biphenyls in San Francisco Bay (USA)
Authors: Davis Jay A. 
Published: November 2004

Abstract
A simple one-box mass budget model is presented as a first step toward a quantitative understanding of the long-term fate of polychlorinated biphenyls (PCBs) in San Francisco Bay (USA). Sensitivity analysis indicated that the most influential input parameters were degradation half-life in sediment, Kow, outflow, average PCB concentration in sediment, and depth of the active sediment layer. Moderately influential parameters included organic carbon content of suspended solids, sediment burial mass transfer coefficient, and Henry's law constant. If external loading could be eliminated entirely, the mass of PCBs in the bay is predicted to drop to half of the present value in 20 years. The model predicts that sustained loading of 10 kg year−1 would prevent the total PCB mass in the bay from ever dropping below 10% of the present mass. With a sustained loading of 20 kg year−1, the model predicts that the total PCB mass would never fall below about 25% of the present mass. The half-lives in the bay for the individual PCB congeners evaluated in this report ranged from four years for PCB 18 to 30 years for PCB 194.
Use of cyclodextrin and calcium chloride for enhanced removal of mercury from soil
Authors: Wang Xiaojiang , Yolcubal Irfan , Wang Weizi , Artiola Janick , Maier Raina , Brusseau Mark 
Published: November 2004

Abstract
The use of solutions containing carboxymethyl-β-cyclodextrin (CMCD) or CaCl2 for enhancing the removal of Hg from a sandy soil was investigated using batch and column experiments. The retention of Hg appeared to be controlled by specific adsorption reactions, which greatly constrained Hg removal when using water (KNO3 solution) to flush columns packed with contaminated soil. The results showed that the two reagents did enhance the removal of Hg from the soil. For example, 81% and 60% of Hg was recovered after 50 pore volumes of flushing with 50 mM CaCl2 and 2 mM CMCD, respectively, compared to 24% recovery for a 10 mM KNO3 solution. However, significant tailing and delayed recovery of Hg during the elution process occurred in the presence of all reagents, indicating that the removal of Hg from the soil was rate limited.
Baseline toxicity of a chlorobenzene mixture and total body residues measured and estimated with solid-phase microextraction
Authors: Leslie Heather A. , Hermens Joop L. M. , Kraak Michiel H. S. 
Published: November 2004

Abstract
Body residues of compounds with a narcotic mode of action that exceed critical levels result in baseline toxicity in organisms. Previous studies have shown that internal concentrations in organisms also can be estimated by way of passive sampling. In this experiment, solid-phase microextraction (SPME) fibers were used as a tool to estimate the body residues, which were then compared to measured levels. Past application of SPME fibers in the assessment of toxicity risk of samples has focused on separate exposure of fibers and organisms, often necessitated by the amount of agitation needed in order to achieve steady state in the fibers within a convenient time period. Uptake kinetic studies have shown that in SPME fibers with thin coatings, equilibrium concentrations can be reached without agitation within the time frame of a toxicity test. In contrast to toxicity experiments to date, the SPME fibers in the current study were exposed concomitantly to the test water with the organisms, ensuring an exposure under the exact same conditions. Fibers and two aquatic invertebrate species were exposed to a mixture of four chlorobenzenes with a narcotic mode of action. The total body residue of these compounds in the organisms was determined, as was the acute toxicity resulting from the accumulation. The total body residues of both species were correlated to the total concentrations in SPME fibers. It was concluded that toxicity could be predicted based on total body residue (TBR) estimates from fiber concentrations.
Monitoring polynuclear aromatic hydrocarbons in aqueous environments with passive low-density polyethylene membrane devices
Authors: Carls Mark G. , Holland Larry G. , Short Jeffrey W. , Heintz Ron A. , Rice Stanley D. 
Published: November 2004

Abstract
Low-density polyethylene membranes, typically filled with triolein, have been previously deployed as passive environmental samplers designed to accumulate nonpolar hydrophobic chemicals from water, sediments, and air. Hydrocarbons in such samplers, known as semipermeable membrane devices (SPMDs), diffuse through pores in the membranes and are trapped in the central hydrocarbon matrix, mimicking uptake by living organisms. Here, we describe laboratory and field verification that low-density polyethylene membrane devices (PEMDs) without triolein provide reliable, relatively inexpensive, time-integrated hydrocarbon sampling from water. For comparison, polynuclear aromatic hydrocarbon (PAH) uptake in SPMDs and pink salmon eggs also was studied. Total concentrations of PAH accumulated by PEMDs were highly correlated with concentrations in water (r2 ≥ 0.99) and linear over the range tested (0–17 μg/L). Higher-molecular-mass PAH preferentially accumulated in PEMDs and in pink salmon eggs, but the source of oil in PEMDs remained identifiable. Accumulations of PAH were highly similar to those in SPMDs. The PEMDs retained approximately 78% of accumulated total PAH for 40 d in clean water. Thus, a simple plastic membrane can be conveniently used for environmental monitoring, particularly during situations in which contaminant concentrations are low (in the parts-per-billion range), variable, and intermittent.
A historical record of mercury contamination in southern florida (USA) as inferred from avian feather tissue: Contribution R-09888 of the Journal Series, Florida Agricultural Experiment Station
Authors: Frederick Peter C. , Hylton Becky , Heath Julie A. , Spalding Marilyn G. 
Published: November 2004

Abstract
During the late 1980s, the upper trophic-level biota of the Everglades (FL, USA) was recognized as being highly contaminated with mercury (Hg). However, the timing and pattern of that increase is poorly known, and no information is available about mercury contam ination in Everglades wildlife prior to 1974. We measured methylmercury concentrations in feathers of white ibises (n = 33), great egrets (n = 7), anhingas (n = 21), and great blue herons (n = 12) from museum specimens collected from 1910 through 1980 and combined them with more recent feather samples collected from live birds (1985–2000, n = 98, 37, 49, and 7, respectively). We found no evidence of contamination of museum samples with inorganic mercuric preservatives (0.01–0.28% of total Hg in feathers). All species showed relatively low concentrations of mercury through the 1970s (&lt;5 μl/L dry wt for anhingas, ibises, and egrets, &lt;10 μl/L for herons). Samples from all species taken during the 1990s showed a large and significant increase (4–5X) in MeHg concentration. This evidence suggests that most of the increase in Hg deposition during the 20th century in south Florida occurred during the last two to three decades, which is consistent with information about local source deposition. Contamination levels prior to the 1970s appear to have been associated with normal reproduction in these birds, suggesting partial evidence for a threshold of reproductive impairment.
Soil-air relationships for toxaphene in the southern United States
Authors: Bidleman Terry F. , Leone Andi 
Published: November 2004

Abstract
Volatilization of toxaphene residues from agricultural soil was investigated at farms in the southern United States by collecting air samples 40 cm above the soil. The concentration of total toxaphene ranged over several orders of magnitude, from &lt;3 to 6,500 ng g−1 dry weight in soil, and &lt;0.3 to 42 ng m−3 in air. A log-log plot of total toxaphene concentrations in soil and overlying air showed a significant (p &lt; 0.001) positive relationship, with r2 = 0.73. The soil/air fugacity ratio (FR) for 26 events ranged from 0.4 to 238, exceeded FR = 1.0 (soil/air equilibrium) in 24 events, and exceeded FR = 10 in 17 events. This indicates that toxaphene in air sampled at 40 cm generally was not at equilibrium but undersaturated with respect to the soil. Compared to a technical toxaphene standard, chromatographic profiles of toxaphene residues in soil and air showed alterations due to preferential degradation and volatilization of the components. Peaks matching the retention times of labile octachlorobornanes B8–531 and B8–806 + B8–809 were depleted in both soil and air relative to the more recalcitrant B8–1413 + B8–1945 and B8–2229. For each event, log-log plots were made of the dimensionless soil/air concentration quotient (Q) versus liquid-phase vapor pressure (PL, Pa) for 10 toxaphene components (peaks containing coeluting congeners) that spanned the volatility range of hepta- to nonachlorobornanes. Statistically significant linear relationships were obtained with r2 values for most events ranging from 0.54 to 0.96. Slopes for all but one event ranged from −1.01 to −1.53 and averaged −1.28 ± 0.20. When regressions were carried out for only components one to nine, which cover the vapor pressure range of most components reported in ambient air, the average slope was reduced to −1.02 ± 0.15. Previous models of toxaphene emission, transport, and deposition have considered only total toxaphene. These results provide a basis for modeling soil/air exchange on the basis of single congeners or groups of congeners having similar volatilities.
Use of powdered coconut charcoal as a toxicity identification and evaluation manipulation for organic toxicants in marine sediments
Authors: Ho Kay T. , Burgess Robert M. , Pelletier Marguerite C. , Serbst Jonathan R. , Cook Howard , Cantwell Mark G. , Ryba Stephen A. , Perron Monique M. , Lebo Jon , Huckins James , Petty Jimmie 
Published: November 2004

Abstract
We report on a procedure using powdered coconut charcoal to sequester organic contaminants and reduce toxicity in sediments as part of a series of toxicity identification and evaluation (TIE) methods. Powdered coconut charcoal (PCC) was effective in reducing the toxicity of endosulfan-spiked sediments by 100%. Powdered coconut charcoal also was effective in removing almost 100% of the toxicity from two field sediments contaminated with polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Powdered coconut charcoal did not change the toxicity of ammonia or metal-spiked sediments; however, there was some quantitative reduction in the concentrations of free metals (element specific) in metal-spiked sediments. Powdered coconut charcoal is an effective, relatively specific method to sequester and remove toxicity from sediments contaminated with organic contaminants.
Photochemical transformation and phototoxicity of 1-Aminopyrene
Authors: Zeng Kui , Hwang Huey-Min , Dong Shiming , Shi Xiaochun , Wilson Kaneytta , Green Jacinta , Jiao Yuguo , Yu Hongtao 
Published: November 2004

Abstract
1-Aminopyrene (1-AP) is an environmental mutagen and a metabolite of 1-nitropyrene (1-NO2P). On light irradiation, 1-AP transforms into oxidation products with a half-life of 7.1 min in 10% methanolic buffer. The presence of DNA or free-radical/singlet oxygen scavengers 1,4-dithiothreitol, histidine, or NaN3 slows down 1-AP photochemical reaction. The photoproducts identified include 1-hydroxyaminopyrene, 1-nitrosopyrene, 1-NO2P, 1-amino-x-hydroxypyrene, and three covalent dimers. Since it is known that 1-NO2P and 1-nitrosopyrene are genotoxic and 1-hydroxyaminopyrnene can react with DNA to form covalent adducts, we used the Mutatox® test to assess the toxicity of 1-AP and its photoproducts. It was found that the lowest-observed-effect concentrations for 1-AP, 1-AP photoproducts, and 1-NO2P are 1.25 μM, 10 μM, and NA (no mutagenic response was seen at this concentration range) in direct medium (no S-9) and NA, 5 μM, and 0.625 μM in S-9 medium, respectively. Therefore, 1-AP photoproducts are more genotoxic than 1-AP itself in the S-9 medium and more mutagenic than 1-NO2P in the direct medium. Thus, 1-NO2P alone cannot account for all the mutagenicity of the photoproducts. Irradiation of 1-AP together with DNA leads to covalent DNA adduct formation possibly via the 1-hydroxyaminopyrene intermediate. In this study, ultraviolet-A (UVA) was used at approximately the same magnitude as the outdoor UVA irradiance. Considering the half-life of 1-AP in the test solutions in this study, the aquatic biota (including humans) near the surface layer of a static water body are most likely subjected to the photoinduced toxicity of the study compound. The biota at the lower depths will also be affected if turbulence becomes a significant factor in enhancing the exposure risk for aquatic organisms.
Reduced grazing rates in Daphnia pulex caused by contaminants: Implications for trophic cascades
Authors: Bengtsson Göran , Hansson Lars-Anders , Montenegro Katia 
Published: November 2004

Abstract
Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p′-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via water or a vector, Scenedesmus spp., was assayed in laboratory experiments. The phytoplankton biomass was estimated from the chlorophyll content, and the pesticide uptake and turnover pattern in Daphnia and Scenedesmus were determined from parallel experiments with a radiolabeled source. Scenedesmus spp. relative net growth rate was inversely and linearly related to the density of the grazer. Daphnia pulex exhibited significant reductions in grazing rate: 30% for those pre-exposed to p,p′-DDE via water and 40% for D. pulex pre-exposed to glyphosate via Scenedesmus spp. Through the process of trophic cascading, this impaired grazing allowed Scenedesmus spp. to grow at higher rates, 70 and 60%, respectively. The reduced grazing efficiencies were associated with the treatments that gave the highest body burden of p, p-DDE (70 μg/g dry wt) and the lowest of glyphosate (13 mg/g dry wt). The pattern of results suggests a toxic effect of p,p′-DDE on D. pulex and a growth enhancement of Scenedesmus spp, in response to nitrogen and phosphorus in glyphosate excreted by D. pulex.
Persistence of selected organophosphate and carbamate insecticides in waters from a coastal watershed
Authors: Bondarenko Svetlana , Gan Jianying , Haver Darren L. , Kabashima John N. 
Published: November 2004

Abstract
Organophosphate and carbamate compounds are among the most widely used pesticides. Contamination of surface water by these compounds is of concern because of potential toxicity to aquatic organisms, especially those at lower trophic levels. In this study we evaluated the persistence of diazinon, chlorpyrifos, malathion, and carbaryl in waters from various sites in the Newport Bay-San Diego Creek watershed in southern California (USA). The persistence of diazinon and chlorpyrifos was much longer than that of malathion or carbaryl and was further prolonged in seawater. Microbial degradation contributed significantly to the dissipation of diazinon and chlorpyrifos in freshwater, but was inhibited in seawater, leading to increased persistence. In contrast, degradation of malathion and carbaryl was rapid and primarily abiotic. A greater temperature dependence was observed for carbaryl degradation in all waters and for diazinon degradation in freshwater. The interactions of pesticide persistence with water location, temperature, and type of pesticides suggest that site- and compound-specific information is needed when evaluating the overall ecotoxicological risks of pesticide pollution in a watershed. Because the persistence of diazinon and chlorpyrifos may increase significantly in seawater, mitigation should occur before the pesticides reach seawater. The relatively short persistence of these compounds in freshwater suggests that practices aimed at extending residence time (e.g., diversion to wetlands) may effectively reduce pesticide output to downstream water bodies.
Effect of thioarsenite formation on arsenic(III) toxicity
Authors: Rader Kevin J. , Dombrowski Paul M. , Farley Kevin J. , Mahony John D. , Di Toro Dominic M. 
Published: November 2004

Abstract
Soluble arsenic(III)-sulfide complexes (thioarsenites) play a significant role in the chemistry of arsenic in reducing, sulfidic environments at circumneutral pH. Chemical equilibrium calculations using thioarsenite thermodynamic data from the literature indicate that the formation of a dithioarsenite complex, AsS(OH)(SH)−1, reduces the concentration of the uncomplexed inorganic As(III) species present (defined Σ H3AsO3, where Σ H3AsO3 = AsO3−3 + HAsO3−2 + H2AsO3−1 + H3AsO3). With enough sulfide present, soluble As(III) is dominated by this complex. Therefore, it is of interest to examine the effect of dithioarsenite formation on As(III) toxicity. The Microtox® acute toxicity test was used for this purpose. Tests performed on solutions with varying S:As ratios indicate that As(III) toxicity is a function of the uncomplexed As(III) concentration rather than the total As(III) concentration. This suggests that the dithioarsenite species is not bioavailable and that its formation reduces As(III) toxicity. Chemical equilibrium calculations and sediment pore-water field data from various sources indicate that, in many sediments, dithioarsenite formation can reduce toxicity.
Avoidance tests with collembola and earthworms as early screening tools for site-specific assessment of polluted soils
Authors: da Luz Tiago Natal , Ribeiro Rui , Sousa José Paulo 
Published: November 2004

Abstract
Avoidance tests with earthworms and collembolans were conducted to demonstrate their feasibility as early screening tools for assessing the toxic potential of metal-polluted soils. Four different soils, with different degrees of metal contamination, were obtained from an abandoned mining area. All possible paired combinations were assessed for an avoidance response by the organisms. Data revealed that both species were able to avoid the most contaminated soils at the center of the ore extraction and treatment areas compared to those collected further away from the mine. However, earthworms and springtails differed in sensitivity to metals, especially when testing the two most polluted soils that had different contamination profiles. Earthworms exhibited a more consistent, less variable response than springtails. Overall results showed that avoidance tests with collembolans and earthworms have the potential to be used as screening tools in ecological risk assessment schemes for contaminated land, to trigger other tests in case of concern. However, further method development is needed to reduce variability in the data, particularly in the Collembola assays, and to gain knowledge about the possible effects of soil properties on the outcome of the tests.