Using Wildlife as Receptor Species: A Landscape Approach to Ecological Risk Assessment

To assist risk assessors at the Department of Energy’s Savannah River Site (SRS), a Geographic Information System (GIS) application was developed to provide relevant information about specific receptor species of resident wildlife that can be used for ecological risk assessment. Information was obtained from an extensive literature review of publications and reports on vertebrate- and contaminant-related research since 1954 and linked to a GIS. Although this GIS is a useful tool for risk assessors because the data quality is high, it does not describe the species’ site-wide spatial distribution or life history, which may be crucial when developing a risk assessment. Specific receptor species on the SRS were modeled to provide an estimate of an overall distribution (probability of being in an area). Each model is a stand-alone tool consisting of algorithms independent of the GIS data layers to which it is applied and therefore is dynamic and will respond to changes such as habitat disturbances and natural succession. This paper describes this modeling process and demonstrates how these resource selection models can then be used to produce spatially explicit exposure estimates. This approach is a template for other large federal facilities to establish a framework for site-specific risk assessments that use wildlife species as endpoints.Current address: Biology Department, University of South Dakota, Vermillion, SD 57069     

Treatment of contaminated soil with phosphorus and manganese oxide reduces lead absorption by Sprague-Dawley rats

This study was conducted to determine the extent of Pb absorption into young rats (Rattus norvegicus var. Sprague-Dawley) fed untreated Pb-contaminated soil or Pb-contaminated soil treated with two different sources of P and P + Mn oxide. Data were compared from an in vitro, physiologically based extraction test (PBET) with the animal data to support the validity of the in vitro test to assess bioavailable Pb from a treated Pb-contaminated soil. Soil with a total Pb concentration of 2290 mg kg(-1) was used. Rats were fed 19 different test diets for 21 consecutive days. The test diets represented 95 g AIN93G rat meal kg(-1) diet with varying proportions of silica sand or soil to provide low, medium, or high doses of Pb from either Pb acetate, treated, or untreated soil. Blood, liver, kidney, and bone Pb concentrations were examined. For all four tissues, Pb concentrations for the Pb acetate groups were significantly higher than concentrations for all the soil groups. In general, either triple superphosphate (TSP) or phosphate rock (PR) treatments resulted in significant reductions in tissue Pb concentrations compared with untreated soil. Blood and kidney Pb concentrations for the PR + Mn oxide group were significantly lower than those of the PR group at the low and high doses. Relative bioavailability of Pb, as measured in all tissues, was significantly reduced when comparing untreated with amended soil. Correlation between the in vitro and in vivo tests, based on bone and liver tissue, showed that the in vitro test is successful at predicting Pb bioavailability.     

Fear,victimization, and stress among urban public school teachers

Data from the National Institute of Education's Safe School Study Report suggested that teachers in American urban public schools are emotionally and physically victimized and that the result is heightened level of stress associated with teaching. This study, which is part of larger, longitudinal project, explores the linkages between reported experiences of victimization by 291 urban public school teachers and task-specific stressors in the performance of the teaching role. The level of reported stress and nature and degree of victimization differ by the grade level taught and the race of the teacher. Generally, minority teachers (black and brown) are less likely to report being stressed or victimized than are white teachers, while elementary school teachers report their work to be most stressful. There is no evidence of a specific causal ordering between fear of victimization and teacher stress. Rather, each may feed upon and facilitate the other.     

A review of in vitro testing systems applicable to diesel health effects research

In vitro mutagenicity and carcinogenicity testing techniques are currently being used to assess the potential risk to man of exposure to diesel exhaust emissions. This paper examines general considerations of such systems, the types of in vitro tests currently available, the advantages and disadvantages of each cell line and type of test, the limitations of in vitro techniques, the alternative human cell lines that could be utilized for diesel health effects studies, and recommendations for future research employing in vitro methods.     

A SCREENING MODEL FOR WATER RESOURCES PLANNING1

ABSTRACT: Techniques of optimization and simulation are merged to select the most efficient arrangement of components for regional water resources development and management. Application is made to the Elkhorn River Basin in Nebraska. The Basin extends over 7,000 square miles and includes 184 proposed reservoirs. Structure sizes, locations and operating policies are selected for optimal plans based on economic efficiency and regional development. Results indicate that substantial savings in time and costs over conventional planning techniques are effected. Agreement between model output and agency design values was noted.     

The sensory basis of prey location by the California leaf-nosed bat Macrotus californicus (Chiroptera: Phyllostomidae)

Summary Macrotus californicus, an insectivorous bat, captures prey on the ground, and shows great sensory flexibility in hunting for prey: it uses high frequency, low intensity, frequency modulated echolocation to locate prey in total darkness, however data from this study suggest that it uses vision preferentially, and switches off its echolocation when adequate illumination is available. When souncs of prey are available it exploits these also. It uses echolocation only 50% of the time at 4.2x10^-2 mL, comparable to ground luminance on a brightly moonlit night, and employs vision even at 10^-3 mL.     

USEPA/paper industry cooperative dioxin study: The 104 mill study

This paper summarizes the distribution of concentrations of 2378 substituted dibenzo-p-dioxins and dibenzofurans in bleached kraft and sulfite mill pulps, wastewater sludges, and treated effluents in the U.S. in mid-1988.