Exposure pathways and contaminant models in the ASTM risk-based corrective action guidance
- Woodward-Clyde Consultants, Oakland, CA (United States)
The ASTM Risk-Based Corrective Action (RBCA) Guidance issued in July 1994 represents a major step in the development of a comprehensive decision-making tool for the assessment and response to subsurface contamination based on protection of human health and environmental resources. The RBCA is structured as a three tiered process of decreasing conservatism by increasing site-specificity. Tier 1 involves preliminary site assessment and comparison of site conditions with a set of risk-based default numerical criteria. If Tier 1 default criteria are exceeded, a site-specific set of criteria for comparison with site conditions may be developed according to Tier 2 and Tier 3. The RBCA process is based on contaminant fate and transport models and exposure parameters consistent with USEPA guidance on risk assessment. The purpose of this presentation is to describe the exposure modeling methodology in RBCA Tier 1 and Tier 2. This will enable risk assessors to better understand the RBCA models and master the transition between Tier 1 (default look-up tables) and Tier 2 (site-specific cleanup goals). The presentation is concluded with an example application of the RBCA process to the development of soil and groundwater cleanup goals for a major redevelopment project in California.
- OSTI ID:
- 242364
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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