The document, "User's Guide: Derivation and Application of Environmental Screening Levels (ESLs)", - Interim Final 2016 (February 2016) is a technical report prepared by staff of the California Regional Water Quality Board, San Francisco Bay Region. Information provided in the document is not intended to establish policy or regulation.
The document presents Environmental Screening Levels (ESLs) for chemicals commonly found in soil and groundwater at sites where releases of hazardous chemicals have occurred. The ESLs are presented in a series of tables. Each table reflects a specific combination of soil, groundwater and land-use characteristics that strongly influence the magnitude of environmental concerns at a given site. This allows the user to select ESLs that are most applicable to a given site.
The Tier 1 ESLs presented in the lookup tables are NOT regulatory cleanup standards. The presence of a chemical at concentrations in excess of an ESL does not necessarily indicate that adverse impacts to human health or the environment are occurring; this simply indicates that a potential for adverse risk may exist and that additional evaluation is warranted.