PARENT SESSION
PW10 - Ecological Risk Assessment
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P835) TWEM: An Integral Model For Estimating Risks To Wildlife Within ARAMS.
Sample, Bradley*,1, 1 CH2M HILL, Sacramento, CA, United States
ABSTRACT- The Army Risk Assessment Modeling System (ARAMS) is being developed to facilitate and standardize human and ecological risk assessments. Assessment of wildlife risks, a key component of ARAMS, requires exposure modeling. The Terrestrial Wildlife Exposure Model (TWEM) was developed and parameterized for incorporation into ARAMS. TWEM generates estimates of total exposure based on ingestion of food, soil, and surface water. Dermal and inhalation exposure are not currently incorporated, but may be in the future. TWEM incorporates exposure data for 26 birds, 21 mammals, and 8 reptiles derived from reports from the U.S. EPA and Oak Ridge National Laboratory. Exposure data for an additional six bird and four mammal species that may occur on Army installations have also been developed. All receptors have been categorized to ecological guilds to allow greater utility of the model. Exposure estimation also requires chemical-specific bioaccumulation models. Existing bioaccumulation models for different wildlife food types have been identified and incorporated. Where bioaccumulation models for different are lacking, data extracted from published literature were used to develop new models. Exposure estimates from TWEM will be integrated within ARAMS to a Terrestrial Toxicity Database developed for the Army to generate estimates of risk. TWEM will allow users to select receptors based on habitat availability at a given contaminated site and species-specific habitat requirements. This model will generate both conservative screening and a more refined exposure estimates by allowing the user to choose other relevant parameters(e.g., Area Factors, site-specific BAFs, regional specific body weights, etc.).
Key words: Ecological Risk Assessment, exposure modeling, terrestrial wildlife, ARAMS