ARCHIVED REPORTS_XR0007116 - Laserfiche WebLink

Home Browse Search

Corrective Action Plan 8 Time Oil Compal Property No 04-049 14000 East Highway 88 Lockeford CA __ September 8 1998 3.0 RBCA EVALUATION A risk evaluation was conducted for the Site to determine whether chemical levels detected in soil and groundwater will pose unacceptable health risks to human receptois for current and future occupants of the Site, and thus require remediation This risk assessment was conducted using the recommended models and parameters of the American Society for Testing and Materials (ASTM) in their Standard Guide for Risk-Based Corrective Action Applied at Petroleum Release Sites E-1739-95 Tier 1 and Tier 2 analysis was conducted for the Site Tier i compares maximum detected concentrations to risk-based screening levels (RBSLs) These RBSLs are calculated through equations that typically use conservative default assumptions The premise is that if the maximum chemical concentrations at the site do not exceed the acceptable levels under the most conservative exposure assumptions, then the site does not pose a potential risk to human receptors Tier 2 calculates site-specific target levels (SSTLs) by incorporating site-specific parameters into the same equations used to calculate Tier 1 RBSLs Tier 2 analysis allows the flexibility of using specific geological, physical, and environmental characteristics of the site in determining chemical exposures and consequential health risks 3.1 CHEMICALS OF POTENTIAL CONCERN Based on the information presented in Section 2 0, the chemicals of potential concern at the site are BTEX in soil and groundwater, 1,2 Dibromoethane in soil, and MTBE in groundwater RBSLs and SSTLs developed in this risk evaluation were compared to maximum concentrations of chemicals of potential concern that have been detected at the site to provide a conservative estimate of risk Time ORV,ockeford\CAP wpd