Risk Variability Due to Uniform Soil Remediation Goals

Establishing and Evaluating the Risk Implications of Uniform Soil Remediation Goals

“…A brief overview of SoilRisk, the methodology, and results of an example application are presented. This paper extends the previous work of Labieniec et al 13 by providing a discussion of the utility of the methodology in establishing uniform soil remediation goals for a region of sites using the example results. In addition, the possibility of reducing the regional risk variability expected with use of a uniform concentration approach by developing a modified uniform concentration approach is examined.…”

“…The average contaminant concentrations are used to calculate exposure-route specific risk and total risk estimates as a function of contaminant concentration in soil. Labieniec et al 13 used SoilRisk to simulate variability in risk across sites in a region when a single contaminant concentration in soil is specified as the remediation goal. SoilRisk incorporates four different exposure scenarios (on-site and off-site residential, on-site commercial/industrial, and on-site recreational).…”

“…Although it is recognized that uncertainty and variability exist with respect to the exposure conditions at any site and the pharmacokinetics and toxicity of any contaminant, the purpose of the methodology developed in Labieniec et al 13 was to evaluate variability in risk due to variability in site transport/fate properties given a particular exposure scenario. Thus, exposure-related parameters and the contaminant carcinogenic potency slope factors used by SoilRisk were treated deterministically, and values were developed, as much as possible, in accordance with U.S. Environmental Protection Agency (EPA) guidance on the reasonable maximum exposure (RME), 16 * 17 which involves deterministic assessment of exposure, risk, and contaminant toxicity.…”

“…To simulate the variability in risk across sites in a region when a single contaminant concentration in soil is specified as the remediation goal, site-related input parameters were considered as probability distribution functions (PDFs) to describe regional variability in site conditions. 13 To provide an example application, site input parameter distributions were developed in Labieniec et al 13 for a small geographic region (Ross County, OH) for which detailed hydrogeologic information is available in the form of a DRAS-TIC 15 map. DRASTIC is a groundwater pollution-potential mapping methodology that results in a map of hydrogeologic settings defined by the major geologic and hydrologic properties that affect and control groundwater and contaminant movement.…”

“…This, of course, ignores the uncertainties associated with site-specific risk assessments. This issue of uncertainty in site-specific risk assessments is discussed further in Labieniec et al) 12 Labieniec et al 13 developed a methodology for evaluating the regional variability in risk associated with the uniform concentration approach for setting soil remediation goals. The methodology is based on SoilRisk, 14 a screening level carcinogenic risk assessment model for organic contaminants in soil that can be applied for a wide range of organic contaminants and exposure scenarios.…”