SoilRisk: Risk Assessment Model for Organic Contaminants in Soil

Abstract

This paper describes in detail a new integrated risk model, SoilRisk, for low-levels of organic pollutants in soil. An analytical model of the fate and transport of organics in unsaturated soil is used where chemical losses from the unsaturated zone occur due to first-order degradation, volatilization at the soil surface, and leaching to the saturated zone. The unsaturated zone module is linked to air dilution/dispersion, saturated zone transport, and dust generation modules to allow estimation of long-term average air, groundwater, respirable dust, and soil contaminant concentrations. With SoilRisk, the carcinogenic risk resulting from a specified contaminant concentration in soil or the contaminant concentration in soil to meet a specified level of risk can be estimated. These model outputs can be evaluated as single values or as cumulative distribution functions, depending on whether the input parameters are specified deterministically or probabilistically. In a subsequent paper, the model is applied to evaluate the risk implications of establishing uniform, concentration-based soil remediation goals.