bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of granular pesticide formulations and soil moisture on avian exposure
Authors: Stafford Tamara R , Best Louis B 
Published: March 2010

Abstract
Two experiments were conducted to evaluate the influence of granular carrier type, pesticide load per granule, and soil moisture on avian risk of adverse effects from granular pesticides. Bird behavior, survival, and brain and plasma cholinesterase activity were used to assess exposure. In the first experiment, silica and corncob granules formulated with fensulfothion at either 1/2 or 1/32 of the median lethal dose (LD50) were offered to captive house sparrows (Passer domesticus) in bands on dry soil. The corncob carrier and granules formulated with 1/2 the LD50 presented the greatest risk to birds. In the second experiment, fensulfothion was formulated on three carrier types (silica, clay, and corncob) and offered to house sparrows in bands on wet or dry soil. Overall, formulations with corncob as the carrier and dry soil conditions presented the greatest risk to birds. Wet soil conditions reduced the risk of adverse effects for all three granular carrier types, but the greatest risk reduction occurred with corncob and silica granules. Differences in adverse effects associated with various carrier types and soil moisture conditions can add complexity when assessing risk to birds from granular pesticides.
Stress protein synthesis and peroxidase activity in a submersed aquatic macrophyte exposed to cadmium
Authors: Siesko Melanie M , Fleming Walker J , Grossfeld Robert M 
Published: March 2010

Abstract
Sago pondweed (Potamogeton pectinatus L.) was exposed to CdCl, to evaluate peroxidase (POD) activity and stress protein (SP) synthesis as potential biomarkers of contaminant stress in an aquatic plant. Peroxidase activity did not increase in sago pondweed incubated for 24 h in a liquid culture medium containing 0.5, 0.75, or 1 mM CdCl,. By contrast, at each of these CdCl, concentrations, SPs of 162, 142, 122, 82, and 61 kDa were preferentially synthesized, and synthesis of a 66-kDa protein was reduced relative to controls. Peroxidase activity also did not change in sago pondweed rooted for 21 d in agar containing 1 mM CdCl2, despite the lower growth rate, lower protein content, and brown discoloration of the plants. Only when the plants were grown 7 or 21 d on agar containing 10 mM CdCl, were the growth retardation and phenotypic deterioration accompanied by significantly increased POD activity. In contrast, plants rooted for 7 d in agar containing 1 mM CdCl, were not significantly discolored or retarded in growth, yet they preferentially synthesized SPs of 122, 82, and 50 kDa and synthesized proteins of 59 and 52 kDa at reduced rates relative to controls. Similar changes in protein synthesis were accompanied by signs of depressed growth after 21 d of incubation with 1 mM CdCl, and with 7 or 21 d of exposure to 10 mM CdCl,. These data indicate that changes in SP synthesis may precede detectable alterations in growth of aquatic plants and, therefore, may be a potentially useful early biomarker of contaminant stress. However, further studies will be required to determine whether the SP response is measurable during exposure to environmentally relevant contaminant levels.
Development of a chronic sublethal sediment bioassay using the estuarine amphipod Leptocheirus plumulosus (Shoemaker)
Authors: Emery Vallen L , Moore David W , Gray Brian R , Duke B Maurice , Gibson Alfreda B , Wright Rachel B , Farrar J Daniel 
Published: March 2010

Abstract
Based on the need for a test to evaluate chronic sublethal toxicity in estuarine sediments, a 28-d sediment bioassay with the estuarine amphipod Leptocheirus plumulosus (Shoemaker) was developed. The test was initiated with animals less than 2 weeks old (i.e., 425–600 μm sieved size class). Test endpoints included survival, growth (μg dry weight/d), and reproduction (number of neonates/surviving female). Factors with the potential to influence test animal performance (i.e., nontreatment factors) such as artificial sea salts, salinity, food ration, size at test initiation, intraspecific density, sediment grain size, and diet were evaluated. For example, intraspecific densities between 10 and 60 animals/beaker (i.e., 0.18–1.4 animals/cm2) did not affect survival, growth, or reproduction. Similarly, L. plumulosus were tolerant of a wide range of sediment grain sizes with only extremely fine grained (e.g., &gt;75% clay) or coarse grained (e.g., &gt;75% sand) material significantly affecting survival, growth, and reproduction. Test performance criteria included control survival (&gt;80%) and reproduction (production of offspring in all control replicates), and response to a reference toxicant test with cadmium chloride in a control chart format.
DDT-like effects as a result of corticosterone treatment in an anuran amphibian: Is DDT a corticoid mimic or a stressor?
Authors: Hayes Tyrone B , Wu Tzu Hao , Gill Tanya N 
Published: March 2010

Abstract
Exposure of tadpoles to dichlorodiphenyl trichloroethane (DDT) induces pathological development of the upper mandible. In the current study, we report a similar pathological development after tadpoles of the Senegal walking frog (Kassina senegalensis: Hyperolidae) were treated with the steroid hormone, corticosterone (CORT) for 5 d at 1.1 μM. Corticosterone-treated tadpoles developed a “hole” in the snout (mandibular fenestration) with complete loss of the upper keratinized beak, denticles, and oral papillae. Histological analysis revealed a loss of connective tissue, epidermis, and dermis, but remaining dermis, dermal skin glands, and epidermis appeared normal. Analysis of cleared and stained specimens showed that there was no loss of chondrocranial elements but that the cornu trabeculae was eroded, and the cartilago infrarostralis was repositioned and reshaped. The similarities in the effects of CORT reported in the current study and the previously reported effects of DDT suggest that DDT “mimics” CORT or that DDT acts as a “stressor” causing an increase in endogenous CORT. These data are important in defining the effects and mechanisms of pesticide action on anuran larval development.
A uniform procedure to estimate the predicted environmental concentration of the residues of veterinary medicines in soil
Authors: Spaepen Katrin R I , van Leemput Leo J J , Wislocki Peter G , Verschueren Christian 
Published: March 2010

Abstract
New guidelines to assess the environmental risk of veterinary medicines (VMs) have been proposed in the European Union. As in any risk assessment, exposure is a factor of critical importance. The predicted environmental concentration (PEC) in soil therefore is a pivotal decision parameter in the assessment procedures for VMs. As presently proposed, phases I and II of the assessment require a PEC at an appropriate level of refinement. Hence, it is necessary to calculate the PEC of VMs in a uniform way. The PEC for VMs depends on animal husbandry practices, on the use pattern of the product, on its kinetics in the treated animals and in soil, on physiological characteristics of these animals, and on the codes of good agricultural practices of excreta collecting, storage, and of fertilizing land. In this paper, basic calculations are presented to estimate the PEC from the concentration of residues in manure, the quantities of manure spread per unit land area, and the depth of incorporation into soil. Expanded calculations allow refinements for treatment of only part of the group of animals, metabolism, periods in house, transformation in manure or soil, and repeated application. Examples presented illustrate the dependence of the PEC on various parameters. The examples allow the examination of the regulatory framework of the phase I PEC and an alternative approach to judge the persistence during manure storage or the persistence in soil is proposed.
A method for evaluating consumer product ingredient contributions to surface and drinking water: Boron as a test case
Authors: Dyer Scott D , Caprara Robert J 
Published: March 2010

Abstract
Boron is a ubiquitous element that enters surface waters via two main routes, weathering of boron-containing rock (e.g., borosilicates) and release of boron in cleaning products through disposal to wastewater treatment systems. Recently, concentrations of boron deemed safe for humans and aquatic organisms, via drinking and surface water exposures, have been published. In comparison, however, little has been published regarding the concentrations and distribution of boron in surface waters. This manuscript describes the geographic distribution of boron in the U.S. and California and details a unique method for estimating the amount of boron in receiving waters from consumer product sources using ROUT, a novel deterministic U.S.-scale surface water modeling system, and the USEPA STORET database. ROUT is a national model that predicts chemical concentrations in U.S. rivers and streams and surface drinking water intakes that receive discharges from publically owned wastewater treatment plants (WWTPs). Over 500,000 river miles are systematically routed through the 18 major hydrologic regions of the continental U.S., excluding Alaska and Hawaii. A geographic information system interface coupled to ROUT provides a readily interpretable map of the predicted influences of environmental loadings on environmental concentrations. In addition, this capability allows for comparisons of ROUT output versus other water quality databases (i.e., STORET database) that are georeferenced. Further, for consumer product ingredients that are measured in surface waters, it may be possible to estimate the relative contribution of that ingredient in surface waters from consumer use. Concentrations of boron in receiving waters, predicted concentrations from consumer products, and the percentage of boron from consumer products were determined for California and the continental U.S. Over 55,000 records of dissolved boron were found in STORET between 1984 and 1993. At least one record was found in 667 counties in 44 states, most west of the Mississippi River. Based on all measurements, the median and 90th percentile boron concentrations for the U.S. were 0.076 and 0.387 mg B/L, respectively. The percent contribution of boron in surface waters from consumer product use and disposal to WWTPs was found to be dependent on the extent of sewage treatment plant effluent/receiving water dilution and natural background boron levels. Where background boron levels and dilution factors were lowest, the percent consumer-derived contributions were the greatest.
Equivalence of concentration–response relationships in aquatic toxicology studies: Testing and implications for potency estimation
Authors: Oris James T , Bailer A John 
Published: March 2010

Abstract
The purpose of this study was to describe statistical procedures to test the equivalence of concentration–response relationships in acute toxicology studies and to illustrate the implications of nonequivalence on potency endpoints such as LC10, LC50, or LC90. A logistic regression model for binary response endpoints such as mortality that allowed for the examination of equivalence of slopes and intercepts of the responses between populations is described. Test statistics were derived from comparing nested regression models. This procedure was used to test the equivalence of concentration versus acute mortality response relationships between two nonpolar, narcotic chemicals in a single population of fish and between two populations of fish with different exposure histories to a polycyclic aromatic hydrocarbon. These case studies illustrate different outcomes in the comparison of concentration–response relationships and demonstrate the need to consider more than a single endpoint (e.g., LC50) in a risk assessment context when nonparallel concentration–responses are observed.
A pharmacokinetic model of cadmium in rainbow trout
Authors: Thomann Robert V , Shkreli Frank , Harrison Scott 
Published: March 2010

Abstract
It has been previously observed that exposure of rainbow trout to Cd from water or food did not result in a steady state for key compartments such as the gill, liver, and kidney. Further, during depuration, the mass of Cd in the kidney continued to increase. A seven-compartment pharmacokinetic model of the disposition of cadmium in the rainbow trout was constructed to obtain insight into these observations. The model considers exchange across the gill from exposure to dissolved (available) Cd in the water and exchange of Cd across the gut wall due to exposure to Cd in the food source. Internal distribution of Cd is via Cd in blood exchanging with aqueous phase Cd in kidney, liver, and a storage compartment. Equilibrium partitioning is assumed between the aqueous phase Cd and bound tissue Cd in each compartment. The model is applied to a data set where trout were exposed under two conditions: Cd primarily in water and primarily in food. The model parameters were obtained from other published exposure experiments as well as calibration to the data. The parameters were not altered between the two exposure pathways. High surface gill sorption and gut biliary transfer were necessary in order to obtain reasonable model calibration. Reproduction of the observed increase in kidney Cd during depuration is obtained with a relatively high partitioning, and model flux calculations indicate a net flux into the kidney during the depuration phase. Model simulations for both water and food exposure routes indicated that the whole body Cd concentration was calculated to reach equilibrium in about 50 d. However, Cd did not achieve a steady state in the kidney where it reached a maximum concentration at seven times whole body. For assessment of Cd risk to trout target tissues, it is concluded that a pharmacokinetic model may be necessary.
Selective toxicity of chlorpyrifos to several species of fish during an environmental exposure: Biochemical mechanisms
Authors: Carr Russell L , Ho Lin Lin , Chambers Janice E 
Published: March 2010

Abstract
The organophosphorus insecticide chlorpyrifos is frequently used for termite control. A small pond near a construction site was contaminated with chlorpyrifos via runoff resulting in the death of several species of fish including largemouth bass, bluegill sunfish, and golden shiners, but not mosquitofish. Inhibition of acetylcholinesterase (AChE) and aliesterases (AliE) was determined in the tissues of exposed fish and the presence of chlorpyrifos was confirmed in fish livers by analytical chemistry. Brain AChE was inhibited 87 to 93% in bass, bluegill, and shiners but only 73% in mosquitofish. Skeletal muscle AChE was inhibited 91 to 97% in bass, shiners, and mosquitofish but only 77% in bluegill. Liver AChE and AliE were inhibited greater than 90% in bass, shiners, and mosquitofish but in bluegill, the activities were inhibited only 86% and 77%, respectively. After 60 d, brain AChE activity in exposed mosquitofish was fully recovered, and liver AliE activity was recovered to about 50% of control values, but there was little recovery of skeletal muscle and liver AChE activities. The sensitivity of these enzymes to inhibition by chlorpyrifos-oxon was assessed by determination of 50% inhibitory concentrations (IC50s). Mosquitofish brain and liver AChE and liver AliE were less sensitive to inhibition than the enzymes from the other species. In contrast, mosquitofish skeletal muscle AChE was more sensitive to inhibition compared to the other species. The lower inhibition of mosquitofish brain AChE and the lower in vitro sensitivity of mosquitofish brain AChE to inhibition by chlorpyrifos-oxon compared to the brain AChE of the other species suggest that the species difference in toxicity exhibited in this exposure resulted primarily from species differences in the sensitivity of brain AChE to inhibition by chlorpyrifos-oxon.
Power, sample size and taxonomic sufficiency for measures of impact in aquatic systems
Authors: Ammann Larry P , Waller William T , Kennedy James H , Dickson Kenneth L , Mayer Foster L 
Published: March 2010

AbstractAs part of a larger program to examine the relationships between laboratory and ambient toxicity, data from a series of 28 marine microcosm experiments, which included both laboratory and field studies, were reanalyzed. The statistical methods applied to the data include log-linear regression models (general and robust) for richness and taxa count data (kingdom, phylum, class, order, family, genus, and species) and Gaussian linear models (general and robust) for community metrics diversity and evenness (Shannon-Weiner's, Simpson's, and Brillouin's) and similarity (Bray-Curtis). In addition, taxonomic sufficiency was determined for each of the metrics examined. For each of the analyses performed, both the statistical power of the analysis and the sample sizes required to achieve a desired level of power were determined. New methods are presented to deal with zero count data. Suggestions on how the power of microcosm tests used in toxicity testing can be increased are provided. The statistical programs developed for the analyses applied to the data analyzed were done in S-PLUS. The programs and directions for their application have been placed on an anonymous FTP site at the University of North Texas.
Correlation of measures of ambient toxicity and fish community diversity in Chesapeake Bay, USA, tributaries—urbanizing watersheds
Authors: Hartwell S Ian , Dawson Celia E , Durell Eric Q , Alden Ray W , Adolphson Peter C , Wright David A , Coelho Gina M , Magee John A , Ailstock Steven , Norman Mike 
Published: March 2010

Abstract
This study was performed to evaluate ambient toxicity conditions in Chesapeake Bay tidal tributaries whose watersheds are impacted by urban development and to further evaluate an existing toxicological risk ranking model. A battery of water-column and sediment bioassays were employed with animals and plants. The study was conducted in coordination with a fish community sampling program. Tests were conducted monthly from April through August 1994 at five sample sites in each of four tidal tributaries. Mortality, reproduction, and growth rates in the water-column assays did not consistently indicate chemical contamination in any system. Chemical analyses did not indicate elevated levels of contaminants in the water column. Sediment bioassays demonstrated greater responses than water-column assays. Sediment in the upstream reaches of the South River demonstrated significant toxicity. Toxicity was also observed at the uppermost Severn River station and the middle Patuxent River station. Chemical analyses of composite sediment samples indicated elevated metals levels in the South River. Some metals were above threshold values in the Patuxent and Wicomico rivers. The AVS/SEM ratios in pore water were below 1 in all cases. Organic analyses demonstrated low level polycyclicaromatic hydrocarbon contamination in all four systems. The toxicological risk ranking model ranked the South River as the most contaminant-impacted site. The Patuxent and Severn rivers were ranked below the South River; however, the ranking model identified specific locations in the Severn and Patuxent rivers that indicate sediment contamination. The Wicomico River had the lowest overall risk score. The Patuxent River requires more intense sampling due to its relatively larger size. The toxicological risk ranking results for sediment were significantly correlated with species diversity forfish communities sampled by bottom trawl. Results were consistent with data from previous years. Regression analysis of 2 years of data indicate that fish community impairment can be predicted with ambient toxicity results.
Interrenal dysfunction in fish from contaminated sites: In vivo and in vitro assessment
Authors: Hontela Alice 
Published: March 2010

AbstractCortisol, synthesized in the interrenal cells of teleost head kidney, has a major role in the physiologic response to physical and chemical stressors. Plasma levels of cortisol increase in physiologically competent fish acutely exposed to stressors such as cadmium or mercury. The effects of chronic low level exposures are less well understood. We have diagnosed an endocrine impairment characterized by a reduced capacity to elevate plasma cortisol levels in response to an acute standardized capture stress in yellow perch (Perca flavescens) and in northern pike (Esox lucius) sampled at sites contaminated by mixtures of pollutants (heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls), by heavy metals, or by bleached kraft mill effluent. Our studies with fish, as well as with amphibians at contaminated sites, demonstrated that low level chronic exposures impair secretion of corticosteroids. We have developed new tests for assessment of the functional integrity of teleost and amphibian interrenal tissue by using an adrenocorticotropic hormone (ACTH) challenge, in vivo and in vitro. The reduced ability to respond to ACTH indicates that the normal neuroendocrine response to stressors may be disrupted and that the ability to cope with biotic and abiotic stressors in the environment may be significantly reduced in the impaired animals.
Factors affecting the biodegradation of phenanthrene initially dissolved in different nonaqueous-phase liquids
Authors: Carroquino Maria Jose , Alexander Martin 
Published: March 2010

AbstractA study was conducted of the importance of measured partitioning rate, the nonaqueous-phase liquid (NAPL)–water interfacial area, and the toxicity of NAPLs to the biodegradation of constituents of NAPLs. Bacterial mineralization of phenanthrene was slower if the compound was initially dissolved in phthalate esters than in aliphatic hydrocarbons with several NAPL–water interfacial areas. The differences were not the result of toxicity of the test NAPLs. The rates of partitioning of phenanthrene from NAPLs to water were faster with larger interfacial areas, but a consistent influence of interfacial area on the rate of mineralization was not evident. The measured rates of partitioning from NAPLs to water under sterile conditions varied among the NAPLs, the mass transfer rates being slower with phthalate esters than with alkanes. The rates of mineralization of phenanthrene initially in NAPLs were correlated with measured partitioning rates, but the rates of biodegradation were sometimes faster than the partitioning rates measured under sterile conditions. Although the rates of biodegradation of a constituent of nontoxic NAPLs are generally related to rates of mass transfer determined under sterile conditions, we suggest that the partitioning rate determined in the absence of microorganisms is not an adequate predictor of the maximum rate of biodegradation of such constituents.
Validity of using linear alkylbenzenes as markers of sewage contamination with interference from tetrapropylene-based alkylbenzenes
Authors: Zeng Eddy Y , Cheng Darwin , Khan Azra R , Vista Cherrie L 
Published: March 2010

Abstract
A previously developed two-component model was used to estimate the magnitude of interference from tetrapropylene-based alkylbenzenes (TABs) in measuring linear alkylbenzene (LAB) concentrations in a sediment core collected from the Palos Verdes Shelf (Los Angeles, CA, USA). The magnitude of such interference generally increased with increasing sediment core depth and was fairly high in deeper sediments, where TABs were abundant relative to LABs. Usage of LABs as sewage markers in sediments is generally valid as long as the approximate ratio of TAB to LAB concentration is less than 10.