Simplified calculation of maximum allowable contaminant concentration in waste-amended construction materials

Abstract

A rational approach is often sought for relating the maximum permissible fractional replacement of traditional materials with construction-quality waste materials in constructed facilities. The development of such an approach hinges on the ability to back-calculate contaminant release rates that correspond to risk-based concentration limits in soil, groundwater or surface-water around the targeted facility. For constructed facilities in which the transport pathway is in the subsurface, the critical release mechanism for the targeted contaminant is leaching. In this paper, a simplified methodology for establishing the maximum allowable contaminant concentration in a waste material-amended concrete is developed. Contaminant leachability equations are coupled with contaminant transport factors and groundwater quality standards. Using the example of a generic contaminant contained in petroleum-contaminated soil (PCS) concrete, a methodology for back calculation of the maximum allowable concentration of the contaminant in the concrete for fixed compliance limits in a proximal well is presented.