bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of sludge amendment on transport and sorption ideality ofs-triazines in soil columns
Authors: Graber Ellen R , Sluszny Chanan , Gerstl Zev 
Published: March 2010

AbstractThe aim of this work was to examine the effect of organic soil amendments (municipal sewage sludge and composted municipal sewage sludge) on transport ideality, sorption equilibrium, and s-triazine (atrazine, simazine, ametryn, and terbuthylazine) retardation compared with nonamended soil. Organic-matter amendment resulted in increased nonequilibrium sorption effects, including early breakthrough, increased breakthrough, and elution front-tailing. Organic amendments likewise caused greater solute retardation compared with transport in nonamended soil columns. As the organic matter content increased, retardation increased and the desorption rate constant decreased. The fraction of fast sorption sites also decreased, resulting in greater sorption non-equilibrium. In a given column, the fraction of fast sorption sites was essentially equal for the different s-triazine compounds. The desorption rate constant decreased as the organic carbon partition coefficient (Koc) increased in the order atrazine &gt; simazine ≥ ametryn &gt; terbuthylazine. Soil amendment with sludge and compost resulted in some nonideal physical transport, which was negligible compared with sorption nonideality effects. The linear sorption isotherm nonequilibrium (LNE) model adequately simulated the measured breakthrough curves. The breakthrough curve for ametryn in an amended, nonrinsed column was identical to that in an amended, rinsed column, indicating that sludge-/soil-derived dissolved organic carbon did not affect ametryn sorption and transport in this system.
Comparative toxicity of four insecticides, including imidacloprid and tebufenozide, to four aquatic arthropods
Authors: Song Mee Young , Stark John D , Brown John J 
Published: March 2010

Abstract
The tolerance of four aquatic organisms to four chemicals (aldicarb, dimethoate, imidacloprid, and tebufenozide) was determined using 48-h acute toxicity tests at 27°C. Species included two saline (Artemia sp. and Aedes taeniorhynchus (Wiedemann)) and two freshwater (Daphnia magna Straus and Aedes aegypti (L.)) organisms. Temperature was also evaluated as a toxicity modifying factor for the freshwater species. Two selective insecticides (imidacloprid and tebufenozide) were compared with two broad-spectrum insecticides, aldicarb and dimethoate. In general, A. taeniorhynchus was the most susceptible, and Artemia sp. was the most tolerant to insecticides used under our experimental conditions. Both aldicarb and dimethoate caused neurotoxicity in all organisms tested. Mortality associated with molting suggested that tebufenozide affected the molting process of all organisms, causing the formation of an incompletely sclerotized head capsule and the failure of ecdysis in the mosquito species. These responses resulted in lethal larval molts. Imidacloprid, on the other hand, caused delayed symptoms of general nerve poisoning compared with the two acetylcholine esterase inhibitors. Our results suggest that both tebufenozide and imidacloprid would be selective insecticides that can be used with reasonable environmental safety toward nontarget aquatic crustaceans. There was a greater correlation of susceptibility to test chemicals within taxonomically close organisms than between organisms that share habitats.
Multispecies toxicity assessment of compost produced in bioremediation of an explosives-contaminated sediment
Authors: Gunderson Carla A , Kostuk Joanne M , Gibbs Mitchell H , Napolitano Guillermo E , Wicker Linda F , Richmond Jacqueline E , Stewart Arthur J 
Published: March 2010

AbstractA multispecies terrestrial test system was used to assess the environmental effectiveness of composting for bioremediation of explosives-contaminated soils. The assessment involved comparing biological responses, from the individual to the community level, in remediated and reference composts. A 6-month greenhouse study incorporated two soil invertebrate species, three plant species and an associated symbiont, and the naturally occurring complement of soil microorganisms. Measured parameters included growth and reproduction of earthworms and isopods; soil mite diversity; soil lipid class composition as an indicator of soil microbial community structure; plant growth, photosynthesis, and reproduction; and root nodulation and symbiotic N2 fixation. Additional short-term toxicity tests of seed germination and earthworm survival were performed to supplement the mesocosm data. Compost prepared from the explosives-contaminated soil inhibited several aspects of plant growth and physiology, but few adverse effects on soil invertebrates were detected. An initial lag in earthworm and isopod reproduction occurred in the reference compost, reflecting some inherent compost differences not associated with contamination, and highlighting the importance and the difficulty of finding appropriate reference soils for assessing hazardous waste sites or remediation technologies. Nonetheless, the results from this study suggested some nonlethal effects from the contaminated-soil compost, primarily to plants. The mesocosm methodology used in this study can bridge the gap between traditional short-term toxicity testing and longer term field assessments, and provide information on ecological effects by explicitly including measurements of multiple species across several levels of ecological organization.
Exposure of captive feral pigeons to fonofos-treated seed in a semifield experiment
Authors: Pascual Juan A , Hart Andrew D M 
Published: March 2010

AbstractThis study aimed to investigate factors affecting risks to birds from toxic seed treatments under typical field use. Feral pigeons (Columba livia) were exposed for 2 d to fonofos-treated wheat seeds by holding them in pens in plots sown at two depths following standard husbandry in winter sowings in English fenland. In the shallow plots, seeds were readily available to pigeons on the soil surface (8.20 seeds/0.25 m2) while in the deep plots little seed was left uncovered (0.20 seeds/0.25 m2). Serum butyrylcholinesterase analysis revealed negligible exposure to fonofos of birds from deep plots but significant exposure of those in shallow plots. Data on body weight and the availability of exposed seed showed that pigeons in the shallow plots stopped eating treated seeds without depleting those exposed on the soil even though the seed consumed was less than 26% of birds' daily food requirements. Neither mortality nor signs of poisoning were observed. Though seeds were treated at the approved rate (1,080 mg a.i./kg seed), fonofos concentration in seeds from the hopper (586.5 mg/kg) and from plots during testing (260.2 and 201.7 mg/kg for days +1 and +2 after sowing, respectively) was substantially lower. In this experiment, the avoidance of fonofos-treated seeds together with the low concentration of fonofos in seeds prevented pigeons from ingesting a lethal dose. In the wild, however, pigeons are poisoned occasionally by fonofos, and it has yet to be determined under what conditions this occurs.
Esterase activity and allele frequency in field populations of Simulium equinum (L.) (Diptera: Simuliidae) exposed to organophosphate pollution
Authors: Parker Penelope Judy-Ann Nicole , Callaghan Amanda 
Published: March 2010

Abstract
Esterase activity and allele frequencies in field populations of blackfly larvae, Simulium equinum, were used in a preliminary study to identify any long-term genetic effects of low-level organophosphate insecticide exposure in rivers and streams. Esterase mean activity in S. equinum collected downstream from a cress farm where malathion 60 was periodically applied was significantly higher than in a population taken from a clean site. Polyacrylamide gel electrophoresis analysis of esterase electromorphs revealed that elevated esterase activity was correlated with fast-running dark-staining alleles, whose frequency and activity was significantly higher in blackflies from the polluted site. The genetic differences at the cress site may suggest a long-term exposure to malathion selecting individuals with more active detoxification enzymes. A third S. equinum population was collected downstream from a trout farm and areas of substantial agricultural usage. Esterase activity and high activity allele frequencies were also significantly higher in this population. These preliminary results allow us to conclude that esterases in S. equinum have potential as long-term biomarkers of organophosphate pollution.
Soil-to-indoor air exposure models for volatile organic compounds: The effect of soil moisture
Authors: Sanders Paul F , Talimcioglu Nazmi M 
Published: March 2010

Abstract
Two finite-source models that calculate volatilization of contaminants from soil to indoor air were used to study the effect of soil moisture on indoor air concentrations and inhaled doses, using a representative model volatile organic chemical. A hypothetical scenario was used that assumed that subsurface contaminant diffuses through a layer of clean soil and is then swept into the building interior via advection. Both models simulated depletion of source contaminant via volatilization and degradation. One was an analytical model adapted from the behavior assessment model of Jury et al., which could be used to calculate time-dependent volatilization rates (and indoor air concentrations) as a function of constant soil moisture contents and steady-state moisture advection. The second model, the Integrated Moisture Plus Contaminant Transport (IMPACT) model, had the additional capability of simulating daily and seasonal variations in soil moisture behavior from actual daily temperature and rainfall data. Predicted indoor air concentrations and inhaled doses for the model contaminant varied by up to seven orders of magnitude, depending on the soil moisture conditions and whether or not contaminant degradation was considered. Over extended time periods, inhaled doses predicted under conditions of daily and seasonal variations in soil moisture were in general agreement with those predicted using average soil moistures or average moisture fluxes, suggesting that simplified treatment of soil moisture behavior may be adequate if accurate soil moisture data are available.
The role of ligand flexibility in predicting biological activity: Structure–activity relationships for aryl hydrocarbon, estrogen, and androgen receptor binding affinity
Authors: Bradbury Steven P , Mekenyan Ovanes G , Ankley Gerald T 
Published: March 2010

AbstractRecent studies indicate that the potency and agonist or antagonist activity of steroid hormone ligands are dependent, in part, on ligand–receptor binding affinity as well as the conformation of the ligand–receptor complex. The binding of ligands to hormone receptors is thought to involve interactions by which shapes of both the receptor and ligand are modified in the formation of the ligand–receptor complex. As a consequence, it is essential to explore the significance of ligand flexibility in the development of screening-level structure–activity relationships. In this review, examples are provided of techniques used to generate and screen ligand conformers in the development of quantitative structure–activity relationships and active analogue search algorithms. The biological endpoint modeled was binding affinity of natural ligands and xenobiotics to the aryl hydrocarbon, estrogen, and androgen receptors. These approaches may be useful in future studies to evaluate relationships between ligand structure, receptor binding affinity, and, ultimately, transactivational events associated with receptor interactions with DNA response elements and associated proteins. An improved understanding of ligand–receptor interactions in the context of well-defined effector systems will enhance the development of credible predictive models that can be used to screen large sets of chemicals for potential agonist or antagonistic activity.
Critical appraisal of the evidence for tributyltin-mediated endocrine disruption in mollusks
Authors: Matthiessen Peter , Gibbs Peter E 
Published: March 2010

Abstract
This article reviews the field and laboratory evidence for endocrine disruption in gastropod mollusks caused by tributyltin (TBT). Abundant and undisputed field data link TBT with an irreversible sexual abnormality of female neogastropod snails known as “imposex.” This phenomenon is a masculinization process involving the development of male sex organs, notably a penis and a vas deferens; in certain species the imposition of a vas deferens disrupts oviducal structure and function, preventing normal breeding activity and causing population disappearance. In some species, oogenesis is supplanted by spermatogenesis. A related condition referred to as “intersex” has been reported in littorinid mesogastropods, and these too become unable to lay eggs. Field evidence clearly associates these syndromes with the use of TBT as an antifoulant, chiefly on boat hulls, and dose-related effects can be replicated in laboratory exposures to environmentally relevant concentrations of TBT compounds. It has now been established that imposex and intersex are forms of endocrine disruption caused by elevated testosterone titers that masculinize TBT-exposed females. The precise mechanism by which increased levels of testosterone are produced has not been fully described, but the weight of evidence suggests that TBT acts as a competitive inhibitor of cytochrome P450-mediated aromatase. Some recent data suggest that TBT may also inhibit the formation of sulfur conjugates of testosterone and its active metabolites, thus interfering with its excretion. In summary, TBT-induced masculinization in gastropods, imposex and intersex, is the clearest example of endocrine disruption described in invertebrates to date that is unequivocally linked to a specific environmental pollutant.
Overview of a workshop on screening methods for detecting potential (anti-) estrogenic/androgenic chemicals in wildlife
Authors: Ankley Gerald , Mihaich Ellen , Stahl Ralph , Tillitt Donald , Colborn Theo , McMaster Suzzanne , Miller Ron , Bantle John , Campbell Pamela , Denslow Nancy , Dickerson Richard , Folmar Leroy , Fry Michael , Giesy John , Gray L Earl , Guiney Patrick , Hutchinson Thomas , Kennedy Sean , Kramer Vincent , LeBlanc Gerald , Mayes Monte , Nimrod Alison , Patino Reynaldo , Peterson Richard , Purdy Richard , Ringer Robert , Thomas Peter , Touart Les , Van Der Kraak Glen , Zacharewski Tim 
Published: March 2010

Abstract
The U.S. Congress has passed legislation requiring the U.S. Environmental Protection Agency (U.S. EPA) to develop, validate, and implement screening tests for identifying potential endocrine-disrupting chemicals within 3 years. To aid in the identification of methods suitable for this purpose, the U.S. EPA, the Chemical Manufacturers Association, and the World Wildlife Fund sponsored several workshops, including the present one, which dealt with wildlife species. This workshop was convened with 30 international scientists representing multiple disciplines in March 1997 in Kansas City, Missouri, USA. Participants at the meeting identified methods in terms of their ability to indicate (anti-) estrogenic/androgenic effects, particularly in the context of developmental and reproductive processes. Data derived from structure-activity relationship models and in vitro test systems, although useful in certain contexts, cannot at present replace in vivo tests as the sole basis for screening. A consensus was reached that existing mammalian test methods (e.g., with rats or mice) generally are suitable as screens for assessing potential (anti-) estrogenic/ androgenic effects in mammalian wildlife. However, due to factors such as among-class variation in receptor structure and endocrine function, it is uncertain if these mammalian assays would be of broad utility as screens for other classes of vertebrate wildlife. Existing full and partial life-cycle tests with some avian and fish species could successfully identify chemicals causing endocrine disruption; however, these long-term tests are not suitable for routine screening. However, a number of short-term tests with species from these two classes exist that could serve as effective screening tools for chemicals inducing (anti-) estrogenic/androgenic effects. Existing methods suitable for identifying chemicals with these mechanisms of action in reptiles and amphibians are limited, but in the future, tests with species from these classes may prove highly effective as screens. In the case of invertebrate species, too little is known at present about the biological role of estrogens and androgens in reproduction and development to recommend specific assays.
Developmental neurotoxic effects of dioxin and dioxin-like compounds on domestic and wild avian species
Authors: Henshel Diane S 
Published: March 2010

AbstractIn ovo exposure to dioxin and dioxin-like compounds has been shown to be associated with the development of grossly asymmetric avian brains. This asymmetry is primarily seen in two major brain regions, the forebrain and the tectum, and is detectable in the intact (but isolated) brain or in cross sections, as in computer tomographic (CT) images of the brain. Brain asymmetry has been observed in several wildlife species (heron, cormorant, and eagle) exposed to a mixture of contaminants in the wild, as well as in a domestic species (chicken) exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in ovo under controlled conditions. Asymmetry appears with increasing frequency and severity in embryos and hatchlings exposed to increasing doses of TCDD beginning early in embryonic development. Since asymmetry is evident in early embryos (embryonic day 9) when the braincase is just a thin covering, it is unlikely that brain asymmetry is caused by effects on the braincase rather than on the brain itself. In addition, preliminary histological evaluation of heron hatchling brains indicates that the pyriform (striate) cortex has increased cell density in contaminated versus control brains, although it is not yet clear whether this change in cell density is also manifested asymmetrically. Immunohistochemical analysis of embryonic chicken spinal cord demonstrated that TCDD exposure in ovo also induces a dysmyelination.
Phytoestrogens and anthropogenic estrogenic compounds
Authors: Safe Stephen H , Gaido Kevin 
Published: March 2010

Abstract
The human diet contains a diverse spectrum of endogenous chemicals that exhibit either direct or indirect hormonal activity. These include natural compounds that bind the estrogen, androgen, aryl hydrocarbon, retinoic acid, and retinoic X receptors. In addition, several studies have identified a large number of chemical contaminants that exhibit estrogenic activity (xenoestrogens), and humans are also exposed to these compounds in the diet. Some of these chemicals include diverse phenolics such as bisphenol A, phthalates, polychlorinated biphenyls, and diverse organochlorine pesticides. Most of the endogenous dietary estrogens (including flavonoids and other phytoestrogens) and xenoestrogens are weak estrogen receptor agonists, and based on mass intake, human exposure to phytoestrogens is much higher than to xenoestrogens. The relative importance of dietary exposure to estrogenic compounds is unknown, and their effects will depend on a number of factors, including metabolism and pharmacokinetics, compound potency, serum concentrations, relative binding to serum proteins, levels of exposure during critical periods, and interactions or cross-talk with other endocrine response pathways.
Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco bay region, USA
Authors: Hoffman David J , Ohlendorf Harry M , Marn Carolyn M , Pendleton Grey W P 
Published: March 2010

Abstract
Ault male greater scaup (Aythya marila), surf scoters (Melanitta perspicillata), and ruddy ducks (Oxyurajamaicensis) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic Se concentrations were highest in greater scaup (geometric mean = 67 ppm dry weight) and surf scoters (119 ppm) in Suisun Bay, whereas hepatic Hg was highest (19 ppm) in greater scaup and surf scoters from Tomales Bay. Hepatic Se and Hg were lower in ruddy ducks and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity, including glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH peroxidase), glutathione reductase (GSSG reductase), and glutathione-S-transferase (GSH transferase). Glutathione peroxidase activity was higher in surf scoters and ruddy ducks, and G-6-PDH was higher in greater scaup and surf scoters from Suisun Bay than Tomales Bay. Glutathione reductase (GSSG) was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver, and heart weights; decreased hepatic GSH concentration and G-6-PDH and GSH peroxidase activities; increased ratio of GSSG to GSH; and increased GSSG reductase activity. With increasing hepatic Se concentration, GSH peroxidase increased, but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of Hg and Se and the above variables affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.