Improvement, Verification, and Refinement of Spatially Explicit Exposure Models in Risk Assessment - SEEM Demonstration
Technical Report,01 Feb 2009,01 May 2015
U.S. Army Public Health Command Aberdeen Proving Ground United States
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This project was developed to improve direct testing and refinement of the use of spatial models for wildlife exposure assessments. Past studies focused on whether spatial models could improve the assessment of avian exposures to chemicals in the environment. This study examined the value of spatial models with respect to improving the assessment of small mammal exposures in the environment, and aimed to overcome the disconnect that exists when applying spatial considerations between site-wide averages and an assessment that captures exposures based on species-specific habitat preferences. SEEM model outputs were compared to deterministic risk calculations and directly measured blood-lead based risk calculations to determine if SEEM, increased the reliability of exposure assessment. Three sites were selected two sites in Maryland and one site in California. For small mammals with comparatively small foraging areas, SEEM was no more predictive than site-wide average-based risk calculations. The results emphasized that if habitat is not heterogeneous at ecologically-relevant scales, then SEEM cannot improve risk estimates. Future work will focus on evaluating small mammal exposures where habitat suitability varies over relevant scales. Additionally, SEEM outputs will be evaluated for large mammals and larger foraging areas. Moreover, the larger ESTCP project accomplished the goals of generating greater awareness of the value of spatial models and training risk assessors and managers on using SEEM. The model was also updated in the course of this project.