In June 2013, EPA released updated May 2013 Regional Screening Levels (RSLs) developed using Risk Assessment Guidance from the EPA Superfund Program. RSLs are used for site screening to identify areas, contaminants, and conditions that require further attention at a particular site, and in some cases, are used as cleanup standards. RSLs set forth acceptable concentrations for individual chemicals in the exposure pathways of soil, air, and water. RSLs are risk-based, combining exposure information with EPA toxicity data, and are considered by EPA to be protective for humans over a lifetime of exposure. The RSLs are default values that do not take into account site-specific information, and may be recalculated using site-specific data in appropriate cases.
Most federal and state risk-based environmental cleanup programs reference the RSLs. The RSLs are used as risk-based screening tools to determine if there is a need for further investigation or whether a risk assessment is required to complete site remediation. Based on the current revisions, changes to the RSLs were both chemical specific and based on individual chemical toxicities and risk drivers, and incorporate changes in several major potential exposure pathways.
Since 2011, Kentucky law has required the use of EPA Region 3’s RSLs as screening levels for Kentucky’s voluntary cleanup program. The updated May 2013 RSLs may affect the remediation obligations at a number of sites in the Commonwealth.
To view a complete PDF of the May/June 2013 issue of the Environmental Letter, click HERE.