Environmental Screening Levels Bay Area 2013

The California Regional Water Quality Control Board, San Francisco Region, has recently updated the May 2008 version of the Environmental Screening Levels (ESLs). ESLs are NOT intended to serve as cleanup goals but are conservative concentrations for chemicals commonly found in soil, soil gas, and groundwater, below which it can be assumed to not pose a significant, long-term threat to human health or the environment. Some of the key revisions include:

• Indoor air ESLs – revise industrial values to reflect 8 hours of daily exposure instead of 24 hours
• Soil gas ESLs – consistent with DTSC’s vapor intrusion guidance
• Groundwater ESLs for vapor intrusion – based on two options for soil type
• Toxicity criteria – updated for several chemicals including PCE and TCE
• Hazard index – revise target from 0.2 to 1.0 for non-carcinogens
• Petroleum constituents – defer to 2012 State Water Board’s UST policy

The 2013 ESLs can be downloaded from the link below.

http://www.waterboards.ca.gov/sanfranciscobay/water_issues/programs/esl.shtml

Joseph J. Niland

Principal

Geosyntec Consultants Inc., 3043 Gold Canal Drive, Suite 201, Rancho Cordova, CA 95670

Direct: 916-637-8325; General: 916-637-8048; Cell: 916-302-6314

jniland@geosyntec.com;    www.Geosyntec.com