MP19 Remediation
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(MAH-1117-729463) Risk-based cleanup standards saved $4.5 million in soil remediation.

Mahoney, E¹, Hinckley, D², Cheatwood, C², ¹ Eileen Mahoney Associates, Inc, Philadelphia, PA, USA² EA Engineering, Science & Technology, Sparks, MD, USA

ABSTRACT- Most states have two sets of published standards for chemicals in soil. In Connecticut, these are the Direct Exposure Criteria (DECs), which are meant to protect humans from direct exposures to the soil, and the Pollutant Mobility Criteria (PMCs) which are meant to protect the groundwater from chemicals leaching from soil to groundwater. These values were published years ago using models which incorporated extremely conservative assumptions, in order to be protective in all cases for all sites. The DECs were derived using assumptions which overestimate exposures for most sites, and which are based on a cancer risk of 10-6, even though Connecticut, as most states, has set an acceptable cumulative risk level at 10-5. These values are often used by consultants as cleanup values. This can be a costly mistake. We derived scientifically defensible alternate cleanup values for soil, which are protective of human health, at a site in Connecticut, and saved $4.5 million in remediation costs. The initial estimate for cleanup of site soils to state standards at a site in Connecticut was $8 million. Following derivation of site-specific cleanup targets, the actual cost for soil remediation was $3.5 million, resulting in a cost savings of $4.5 million for the property owner. The alternate cleanup values were accepted by the State and EPA, and the site will be transferred for unrestricted use. We will demonstrate how risk-based cleanup goals were derived for the site.

Key words: Human health risk assessment, Risk-based remediatiom, Alternate cleanup values, Cost effective remediation