Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Chemical fate and transport in the environment determine contaminant bioaccessibility. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. Godard-Codding, Celine Hoff, Dale McMurry, Scott T. International Nuclear Information System (INIS) Exposure models must be appropriate to theĬontaminant exposure in terrestrial vertebrates

However, the general exposure estimation procedure developed herein for birds and mammals is applicable to reptiles and amphibians.

In addition, because toxicological data are scarce for both classes, evaluation of the significance of exposure estimates is problematic. Reptiles and amphibians are not considered because few data exist with which to assess exposure to these organisms. This document provides models and parameters for estimating exposure of birds and mammals. Therefore, exposure models for terrestrial wildlife must include multiple media. They may integrate contamination from several spatially discrete sources. In addition, because most wildlife are mobile, moving among and within habitats, exposure is not restricted to a single location. They may drink or swim in contaminated water, ingest contaminated food and soil, and breath contaminated air. Unlike some other endpoint assemblages, terrestrial wildlife are significantly exposed to contaminants in multiple media. Without sufficient exposure of the receptor to the contaminants, there is no ecological risk. In the context of waste site assessments, stressors are chemical contaminations, and the contact and interaction are uptake of the contaminant by the receptor. In the context of ecological risk assessment, receptors include all endpoint species or communities identified for a site. Exposure can be defined as the coincidence in both space and time of a receptor and a stressor, such that the receptor and stressor come into contact and interact (Risk Assessment Forum 1992). 3), species specific parameters for endpoint species on the Oak Ridge Reservation (ORR) (Sect. 2), methods for estimating parameters of the model (Sect. This report presents a general model for exposure of terrestrial wildlife to contaminants (Sect. Estimating Exposure of Terrestrial Wildlife to ContaminantsĮnergy Technology Data Exchange (ETDEWEB)

Digested organics mark vander hoff