bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polycyclic aromatic hydrocarbon bioaccumulation by meiobenthic copepods inhabiting a superfund site: Techniques for micromass body burden and total lipid analysis
Authors: Klosterhaus Susan L. , Lee Ferguson P. , Chandler G. Thomas 
Published: March 2010

AbstractMicrotechniques for polycyclic aromatic hydrocarbon (PAH) body burden and total lipid analysis were developed and applied to determine the first lipid-normalized bioaccumulation factors for a hydrophobic organic toxicant in a meiobenthic organism (0.063-0.500 mm) living in field-contaminated sediments. The total lipid microtechnique combines the standard Bligh-Dyer extraction method with a colorimetric quantification method for analysis of samples containing 1 to 50 μg lipid. The microtechnique for body burden analysis quantifies PAHs from tissue samples containing as little as 10 pg PAH. Fluoranthene, benz[a]anthracene, and benzo[a]pyrene biota-sediment accumulation factors (BSAFs) were determined for the meiobenthic copepod Microarthridion littorale living in an estuarine U.S. Environmental Protection Agency Superfund site. Gravid female, nongravid female, and male BSAFs were 0.82, 0.54, and 0.36, respectively, for fluoranthene; 0.50, 0.44, and 0.40, respectively, for benz[a]anthracene; and 0.09, 0.12, and 0.15, respectively, for benzo[a]pyrene. Comparison of nonlipid-normalized bioaccumulation factors (BAFs) to BSAFs indicates that M. littorale bioaccumulated PAHs on a gram lipid basis. The BSAFs declined consistently with increasing PAH log Kow for all copepod sex and reproductive stages. Sex- and stage-specific comparisons of BSAFs suggest that differences in lipid content and quality may lead to differences in BSAF values depending on PAH molecular weight and/or hydrophobicity.
Modeling cadmium dynamics in the guts and tissues of small mammals: Dose implications for predators
Authors: Toal Mark E. , Walker Lee A. , Shore Richard F. 
Published: March 2010

AbstractPredators that consume contaminated small-mammal prey are exposed to pollutants present in both the prey tissues and the prey gut. However, the contribution of the prey gut and its contents to the contaminant intake of the predator is often ignored. This study developed a two-compartment model of the dynamics of Cd in a model prey species, the wood mouse (Apodemus sylvaticus). The results from the Cd dynamics model were used to calibrate a revised predator dose estimation methodology that accounted for contaminant uptake by a predator from both prey tissues and guts. The dose to the predator predicted by the revised methodology was compared to that predicted by conventional dose calculations, which account for contaminants in prey tissues only. The conventional approach underestimated Cd dose to a model predator by a factor of 1.2- to 10-fold, depending on prey age and predator behavior. Thus, accounting for the contaminant burden in the prey gut as well as in the tissues can markedly increase dose estimates to predators, and this is likely to be true for most low-bioavailability pollutants. This study has major implications for ecological risk assessment involving food chain transfer of low-bioavailability xenobiotics to predators.
Perpest model, a case-based reasoning approach to predict ecological risks of pesticides
Authors: Van den Brink Paul J. , Roelsma Jan , van Nes Egbert H. , Scheffer Marten , Brock Theo C. M. 
Published: March 2010

Abstract
The PERPEST model is a model that predicts the ecological risks of pesticides in freshwater ecosystems. This model simultaneously predicts the effects of a particular concentration of a pesticide on various (community) endpoints. In contrast to most effect models, PERPEST is based on empirical data extracted from the literature. This model is based on case-based reasoning, a technique that solves new problems (e.g., what is the effect of pesticide A?) by using past experience (e.g., published microcosm experiments). The database containing the past experience has been constructed by performing a review of freshwater model ecosystem studies. This review assessed the effects on various endpoints (e.g., community metabolism, phytoplankton, and macroinvertebrates) and classified them according to their magnitude and duration. The PERPEST model searches for analogous situations in the database, based on relevant (toxicity) characteristics of the compound. This allows the model to predict effects of pesticides for which no effects on a semifield scale have been published. The PERPEST model results in a prediction showing the probability of classes of effects (no, slight, or clear effects, plus an optional indication of recovery) on the various grouped endpoints. This paper discusses the scientific background of the model as well as its strengths, limitations, and possible applications.
Investigation of an onsite wastewater treatment system in sandy soil: Modeling the fate of surfactants
Authors: McAvoy Drew C. , Decarvalho Alvaro J. , Nielsen Allen M. , Cano Manuel L. 
Published: March 2010

Abstract
Field monitoring data for three common laundry detergent surfactants were used to test the applicability of a mathematical model that was developed as a screening-level tool for predicting the fate and transport of consumer product ingredients in septic systems. This model takes into account the simultaneous effects of sorption and biodegradation on the transport of chemicals through a septic system. Predicted groundwater concentrations of alcohol ethoxylate (AE) and alcohol ethoxy sulfate (AES) surfactants were in excellent agreement with measured values. This good agreement was to some extent due to the fact that the biodegradation rates of AE and AES do not vary significantly as a function of the degree of oxygenation of the soil. However, using laboratory-measured soil biodegradation rates for linear alkylbenzene sulfonate (LAS), the model underpredicted measured LAS concentrations in groundwater downgradient from the drainage field. This underprediction was due to the fact that the groundwater beneath the drainage field was anoxic during certain parts of the year and LAS is not degradable under this condition. Measured LAS concentrations were consistent with an assumed in situ soil biodegradation rate that was lower than the rate measured under fully oxygenated laboratory conditions. A limitation of the model is that only one soil biodegradation rate can be input for the saturated zone, even though biodegradation rates may vary seasonally or with distance from the drainage field. However, the model was appropriate and useful as a screening tool for the sorbable organic compounds studied. The applicability of the model to other classes of compounds should be assessed before broader application.
An avian bioassay for environmental estrogens: The growth response of zebra finch (Taeniopygia guttata) chick oviduct to oral estrogens
Authors: Millam James R. , Craig-Veit Christina B. , Batchelder Marianne E. , Viant Mark R. , Herbeck Tina M. , Woods Leslie W. 
Published: March 2010

AbstractThe rat uterotrophic assay is a recommended tier 1 screening assay for environmental estrogens, but no comparable assay exists for altricial birds. We orally dosed zebra finch chicks daily during their linear growth phase (days 5–11) with estradiol benzoate (EB), genistein, methoxychlor, or octylphenol, all dissolved or suspended in canola oil, or canola oil alone, as a vehicle control. On day 12, oviducts were removed, weighed and examined histologically. All doses of EB (0.1–1,000 nmol/g body wt), genistein at 100 nmol/g, and methoxychlor and octylphenol at 1,000 nmol/g, markedly increased oviduct weight, with the highest dose of EB inducing a 60-fold increase over controls. Oviducts were differentiated in a dose-depedent manner to the point of having tubular glands and a pseudostratified, ciliated epithelium at the higher doses of EB. Our earlier results show that EB at 100 and 1,000 nmol/g impairs reproductive performance of zebra finches. Thus, the zebra finch oviduct bioassay measures estrogenicity over a wide dose range and, for EB exposure, can predict impairment in adult reproductive performance. The responsiveness of chick oviducts to estrogen stimulation may serve as a useful marker of estrogen exposure in wild populations of songbirds.
Changes in toxicity and bioavailability of lead in contaminated soils to the earthworm Eisenia fetida (savigny 1826) after bone meal amendments to the soil
Authors: Davies Nicola A. , Hodson Mark E. , Black Stuart 
Published: March 2010

Abstract
The effect of bone meal (Ca5(PO4)3OH) amendments on lead (Pb) bioavailability to Eisenia fetida (Savigny 1826) was investigated. A standard uncontaminated soil was amended with Pb(NO3)2 solution to give Pb concentrations of 7,000 μg/g of soil. After one week, bone meal was added to one half of the soil in the ratio 1:20 bone meal:soil. Immediately after addition of the bone meal, survival times of E. fetida were 23 and 41 h in the bone meal-free and bone meal-amended soil, respectively. Twentyeight days after addition of the bone meal, survival times of Eisenia fetida were 67 h in the bone meal-free soil and more than 168 h in the bone meal-amended soil. In a second experiment, a standard Organisation for Economic Co-operation and Development reproduction toxicity test was carried out, but in addition to Pb(NO3)2 solution, bone meal was added to the soil in the ratio 1:20 bone meal:soil. The bone meal-free soil was left for five weeks before addition of E. fetida. In the bone meal-amended soil, bon emeal was added to the soil one week after addition of the Pb. The soil was left for a further four weeks before addition of Eisenia fetida. Calculated toxicities were significantly lower for the bone meal-amended soil than those calculated for the bone meal-free soil. Twenty-eight-day median lethal concentrations (LC50s; concentration that is statistically likely to kill 50% of the exposed test organism within a given time period ± 95% confidence intervals) of Pb were 4,379 ± 356 μg/g of soil for bone meal-free soil and 5,203 ± 401 μg/g of soil for bone meal-amended soil. Twenty-eight-day median effect concentrations (EC50s; concentration causing a reduction by 50% of a stated parameter) of Pb for weight change were 1,408 ± 198 μg/g of soil for bone meal-free soil and 3,334 ± 731 μg/g of soil for bone meal-amended soil and EC50s for cocoon production were 971 ± 633 μg/g of soil for bone meal-free soil and 1,814 ± 613 μg/g of soil for bone meal-amended soil. Significant mortalities occurred at Pb concentrations of 2,000 μg/g of soil in the bone meal-free soil and 5,000 μg/g of soil in the bone meal-amended soil. Earthworm Pb body load was lower in the bone meal-treated soil than in the bone meal-free soil up to a Pb concentration of 5,000 μg/g of soil. Earthworm Pb body load was approximately 100 μg/g of worm in surviving earthworms in both experiments when significant mortality occurred. Water and diethylenetriamine pentaacetic acid-extractable soil Pb showed good correlations with earthworm Pb body load. These extractions could be used as estimates for Pb bioavailability.
Copper toxicity thresholds for important restoration grass species of the western United States
Authors: W. Mark , Paschke  , Redente Edward F. 
Published: March 2010

Abstract
Copper toxicity thresholds for plant species that are used in restoration activities in western North America have not been established. As a result, ecological risk assessments must rely on toxicity thresholds established for agronomic species, which usually differ from those of species used in restoration. Thus, risk assessors have the potential for classifying sites as phytotoxic to perennial, nonagronomic species and calling for intensive remediation activities that may not be necessary. The objective of this study was to provide a better estimate of Cu toxicity thresholds for five grass species that are commonly used in restoration efforts in the western United States. We used a greenhouse screening study where seedlings of introduced redtop (Agrostis gigantea Roth.), the native species slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners var. Pryor), tufted hairgrass (Deschampsia caespitosa [L.] Beauvois), big bluegrass (Poa secunda J. Presl var. Sherman), and basin wildrye (Leymus cinereus [Scribner&Merrill] A. Löve var. Magnar) and the agricultural species common wheat (Triticum aestivum L.) were grown in sand culture and exposed to supplemental concentrations of soluble Cu of 0 (control), 50, 100, 150, 200, 250, and 300 mg/L. We determined six measures of toxicity: the 60-d mean lethal concentration (LC50), 60-d mean effective concentration (EC50)-plant, 60-d EC50-shoot, 60-d EC50-root, phytotoxicity threshold (PT50)-shoot, and the PT50-root. Results suggest that these restoration grass species generally have higher Cu tolerance than agronomic species reported in the past. Of the species tested, redtop appeared to be especially tolerant of high levels of substrate and tissue Cu. Values of EC50-plant for restoration grasses were between 283 and 710 mg Cu/L compared to 120 mg Cu/L for common wheat. Measured PT50-shoot values were between 737 and 10,792 mg Cu/ L. These reported thresholds should be more useful for risk assessors than those currently used, which are based largely on agronomic crops.
A comparison of chelator-facilitated metal uptake by a halophyte and a glycophyte
Authors: Jordan Fional. L. , Robin-Abbott Molly , Maier Raina M. , Glenn Edward P. 
Published: March 2010

Abstract
Phytoextraction is the use of plants to remove contaminants, in particular metals, from soil via root uptake and translocation to the shoots. Efficient phytoextraction requires high-biomass plants with efficient translocating properties. Halophytes characteristically accumulate large quantities of salts in aboveground tissue material and can have high biomass production. It has been speculated that salt-tolerant plants may also be heavy metal tolerant and, further, may be able to accumulate metals. This study compared growth and metal uptake by a halophyte, Atriplex nummularia, and a common glycophyte, Zea mays, in a minetailing contaminated soil:mulch mixture. Two chelators, ethylenediaminetetraacetic acid (EDTA) and rhamnolipid, were used to facilitate plant metal uptake. Despite a lower growth rate (2% growth/d) in the contaminated soil, the halophyte accumulated roughly the same amount of metals as the glycophyte on a mass basis (30–40 mg/kg dry wt). Neither plant, however, hyperaccumulated any of the metals tested. When treated with EDTA, specific differences in patterns of metal uptake between the two plants emerged. The halophyte accumulated significantly more Cu (2X) and Pb (1X) in the shoots than the glycophyte, but root metal concentrations were generally higher for the glycophyte, indicating that the halophyte translocated more metal from the root to the shoot than the glycophyte. For example, Zn shoot-to-root ratios ranged from 1.4 to 2.1 for Atriplex and from 0.5 to 0.6 for Z. mays. The biodegradable chelator rhamnolipid was not effective at enhancing shoot metal concentrations, even though radiolabeled chelator was found in the shoot material of both plants. Our results suggest that halophytes, despite their slower growth rates, may have greater potential to selectively phytoextract metals from contaminated soils than glycophytes.
Transport behavior of 3,3′-dichlorobenzidine in a freshwater estuary
Authors: Nyman Marianne C. , McCord Kirby , Wood William L. , Blatchley Ernest R. 
Published: March 2010

AbstractLike many hydrophobic organic compounds, 3,3′-dichlorobenzidine (DCB) partitions preferentially to (sediment) particles in lake systems. As such, the behavior of DCB in these systems is substantially affected by the movement of sediments. A field investigation of DCB distribution in sediments of Lake Macatawa (Holland, MI, USA) was initiated. The pattern of DCB distribution within the lake was found to display an oscillatory pattern that was consistent with a wind-driven mechanism of sediment transport. Numerical modeling of seiching behavior supported the hypothesized importance of this mechanism of sediment transport and redistribution. The dynamic behavior of sediment-associated DCB within Lake Macatawa seems to be strongly influenced by phenomena that are common to many freshwater estuaries. As such, the behavior of this system is expected to represent a reasonable model of the dynamic behavior of hydrophobic contaminants in other freshwater estuaries.
Toxicity evaluation of a commercial bioremediation agent mixed with crude oil
Authors: Bidwell Joseph R. , Cherry Donald S. , Merski A. Thomas 
Published: March 2010

Abstract
The toxicity and efficacy of a bacteria-based commercial bioremediation agent (CBA) was assessed through bioassays with juvenile inland silverside minnows, Menidia beryllina, and flask studies of oil degradation. Addition of the CBA to weathered Alaska, USA North Slope crude oil (ANS-521) prior to testing increased toxicity of the water-soluble fraction (WSF) of the oil in both chronic (growth) and acute (mortality) toxicity tests. Time-course toxicity assessment of the water-soluble fraction of the CBA/oil combination indicated increases in effect after 7 to 14 d of mixing that coincided with elevated concentrations of both alkanes and aromatics in the WSF. Under controlled laboratory conditions, the CBA significantly enhanced degradation of the oil compared with a treatment with nutrients alone. The alkane fraction was degraded by nearly 100% over a 42-d period while the aromatic fraction was decreased by 70%. While toxicity testing is not currently required to list bioremediation agents on the product schedule of the National Oil and Hazardous Substances Pollution Contingency Plan, the potential interaction between bioremediation agents and oil should be further investigated and listing requirements reassessed as necessary. Recommendations for future investigations of this issue include characterization of temporal trends in toxicity of CBA and oil mixtures, use of multiple test methods (battery testing) when evaluating toxicity, comparative evaluations of indigenous versus product-derived microorganisms in efficacy studies, and the use of a comparable oil between studies to facilitate comparison of efficacy and toxicity data for different products.
Assessment and characterization of polychlorinated biphenyls near a hazardous waste incinerator: Analysis of vegetation, snow, and sediments
Authors: Blais Jules M. , Froese Kenneth L. , Kimpe Lynda E. , Muir Derek C. G. , Backus Sean , Comba Michael , Schindler David W. 
Published: March 2010

Abstract
Samples of spruce needles, snowpack, and sediment were analyzed in the area around the Alberta Special Waste Treatment Centre (ASWTC) near Swan Hills, Canada, in 1997 and 1998, following a major accidental release of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in October 1996. The PCB concentrations in spruce needles and snow were mostly elevated to the east of the plant and contained congeners that were not present at upwind or distant sites. Several years of annual vegetation monitoring data indicated that PCB emissions increased prior to the reported accident. Within 3 km of the plant, there was a predominance of higher chlorinated congeners penta-, hexa-, hepta-, and octachlorobiphenyls in white spruce (Picea glauca) needles and snow. Polychlorinated biphenyl congener patterns varied seasonally in spruce needles, likely influenced by temperature effects on the volatilization and of particle-bound and vapor phase PCBs in the forest canopy. The similarity of deposition patterns in snow and needles in 1997 and 1998 suggested the PCBs in the surrounding area were derived by long-term fugitive releases of PCBs rather than an accidental release. In addition, hexachlorobenzene, a combustion byproduct of chlorinated organics in waste incinerators, was not measured at elevated concentrations in spruce needles or snow east of the facility and, when detected, was not correlated with PCB concentrations. A radiometrically dated sediment core from nearby Chrystina Lake (AB, Canada) showed a gradual increase in annual PCB flux during the early years of operation of the ASWTC, followed by a higher PCB flux in 1997, indicating that the lake may have been directly contaminated by the accidental release.
Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas)
Authors: Cancilla Devon A. , Baird J. Christopher , Geis Steven W. , Corsi Steven R. 
Published: March 2010

AbstractThis paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox® was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.
Tributyltin causes masculinization in fish
Authors: Shimasaki Yohei , Kitano, Takeshi , Oshima Yuji , Inoue Suguru , Imada Nobuyoshi , Honjo Tsuneo 
Published: March 2010

Abstract
We examined the effect of tributyltin (TBT) on the sex differentiation process in genetically female Japanese flounder (Paralichthys olivaceus). The fish were fed an artificial diet containing tributyltin oxide (TBTO) at concentrations of 0.1 and 1.0 μg/g diet from 35 to 100 d after hatching, which includes the sex differentiation period. The ratio of sex-reversed males significantly increased to 25.7% of the flounder fed the 0.1 μg/g diet and to 31.1% of those fed the 1.0 μg/g diet compared with the control (2.2%). From morphological and histological examination of the fish in the TBT-treated groups, normal females had typical ovaries and sex-reversed males had typical testes. These results clearly demonstrated the masculinization of flounder exposed to TBTO. This is the first report of TBT inducing sex reversal in vertebrates.