HEXAVALENT CHROMIUM-CONTAMINATED SOILS - OPTIONS FOR RISK ASSESSMENT AND RISK MANAGEMENT

Risk assessment involves establishing scientifically defensible dose-r esponse relationships for end points of concern. For Cr(VI)-contaminat ed soils, this includes conducting dose-response assessments for blood , Liver, and kidney toxicity following oral exposure; lung cancer foll owing inhalation exposure; and allergic contact dermatitis following d ermal exposure. This dose-response information is then integrated with a site-specific exposure assessment (or default assumptions) in order to develop a site-specific (or generic) soil criterion within the fra mework of a comprehensive risk characterization. Risk managers develop cleanup standards designed to protect against all possible adverse ef fects, taking into account these site-specific (or generic) criteria a nd other factors such as technical feasibility, cost-benefit analyses, and sociopolitical concerns. Recently a push for cost-benefit analyse s of environmental decisions has occurred, further supporting the need for risk assessors to prepare a comprehensive risk characterization, with its attendant uncertainties. These risk assessment and management issues are brought to the forefront by risk assessors and risk manage rs dealing with Cr(VI)-contaminated soils. This article offers a revie w and analysis of the risk characterization of Cr(VI)-contaminated soi ls, showing that the differing toxicities with route of exposures do n ot necessarily lead to different characterizations of risk. Soil conce ntrations in the range of 130 to 450 ppm appear to protect against non cancer toxicity hom oral exposure, cancer toxicity from inhalation exp osure, and allergic contact dermatitis from dermal exposure. (C) 1997 Academic Press.