Index to Western Geo-Engineers WEB Site, Western Geo_Engineers provides a board array of enviromental geologic services:

Western Geo-Engineers (WEGE)
A FULL SERVICE ENVIRONMENTAL CONSULTING FIRM
(530) 668-5300; Fax (530) 662-0273; wege@cal.net

Risk and Fate Assessments

The current practice in determining risk on a site usually starts with a quick look up table comparison. In California the contaminate concentrations are usually compared to the levels found in the Environmental Screening Levels (ESLs), put forth by the California Regional Water Quality Control Board, San Francisco Bay Region. These are more often used instead of the California Human Health Screening Levels (CHHSLs) because the ESL list contains numbers for mixtures of compounds. To properly use either of these tables for volatile compound requires the collection of vapor samples. If contaminate levels exceeds the limits found on the list then it is necessary to do further site studies.

For most petroleum sites, the standard (RBCA) screening models are sufficient for assessing a site. Occasionally a site needs further or more complicated assessment.