Abstract: Oil Field and UST Site Closures Using RBCA: An overview of the RBCA methodology and the current nationwide implementation of RBCA with an emphasis on California, including a case study of an oil field closure.

NIELSEN, JESPER, ZymaX envirotechnology, inc. San Luis Obispo, CA

Large cost savings are possible when traditional fixed limit cleanup targets are replaced with Risk Based Corrective Action (RBCA) in combination with an integrated approach to data gathering for site assessment and cleanup target development.

The USEPA has advocated use of risk assessment principles, developed for CERCLA, RCRA and Superfund, for petroleum hydrocarbon sites in order to allocate scarce cleanup funds more intelligently. Allocating resources to high risk sites and allowing natural attenuation at low risk sites results in more sites remediated for the same cost without increasing risk.

A formulaic version for use of risk assessment principles was developed as ASTM Standard E 1739-95 to facilitate use by a broader audience. Software tools for the implementation of the ASTM standard feature.

1. Analytical Fate & Transport Model.

2. Standard Exposure Factors & Default.

3. Chemical/Toxicological Database Users provide site-specific data to determine exposure concentrations, average daily intake, baseline risk levels, and riskbased cleanup levels.

Cleanup of petroleum hydrocarbon sites will on the average be cheaper using RBCA than with the use of fixed limit cleanup targets. A Central Coast oil field case study shows 50% savings.

AAPG Search and Discovery Article #90935©1998 AAPG Pacific Section Meeting, Ventura, California