A RISK-BASED APPROACH FOR MANAGING HAZARDOUS-WASTE

In 1992, the U.S. Environmental Protection Agency (EPA) proposed risk-based management of hazardous waste. A major component of the proposed rule is the determination of non-site-specific screening concentration levels from waste leachate. Ground water at a downgradient exposure point must not exceed those screening levels, or more stringent requirements would apply. The screening concentration level is determined with verified models and equations that simulate the transport and attenuation of chemicals as they travel from the source area to the exposure point. A consortium of screening levels is determined in this paper by considering varying physical, chemical, and biological conditions. In addition, a method is developed for multicomponent leaching from contaminated soils in a landfill to determine the time-dependent behavior of a finite source. Finally, this paper discusses infiltration rate through the clay liner.