Use of Risk Analysis on Remedial Alternatives

Abstract

Quantitative risk assessment (RA) is a tool used in determining a remedial alternative’s effectiveness of reducing public health risk. The No-Action Alternative RA examines both present, existing and future-use conditions if no remediation were to occur at a site. Under the Remedial Investigation/Feasibility Study (RI/FS) guidance, remediation of a site may not be required if the carcinogenic risk is within 1 × 10−4 to 1 × 10−7. Although the calculated risks for the sites in this paper were within this range, several standards were exceeded. Risk analyses conducted for both sites determined the effect of various remedial alternatives on the level of risk if the standards were met. These risk analyses may greatly aid in the defense of the No-Action Alternative. Site A is an active facility in Pennsylvania involving volatile organic compounds (VOCs) contamination. The No-Action Alternative risk was 2 × 10−6 and included contact with VOCs in the soils and ground water. Three soil and two water supply alternatives reduced the risk by 2–10 times, while the two water supply alternatives increased the risk by two orders of magnitude. Site B involves VOCs and PCBs contamination at a closed landfill in New York. The No-Action Alternative risk was approximately 4 × 10−5 for this site. Four alternatives reduced the risk to approximately zero, while the two collection and treatment alternatives did not effect the risk.

This paper is being published in a modified form in the Proceedings for Certified Hazardous Material Managers (CHMM) Conference, Ann Arbor, MI, June 25–27, 1990.