Uncertainties in Estimating Chemical Degradation and Accumulation in the Environment

Abstract

Dwindling landfill capacities, rising landfill costs, and the public health hazards posed by landfill operations have caused many communities to consider incineration of their municipal solid wastes (MSW). Recently, however, concerns regarding the potential human health risks posed by MSW incinerators have fueled widespread opposition to the operation of these facilities. These concerns often focus on the human health risks associated with exposure to contaminants that are emitted from the stacks of MSW incinerators and that may ultimately accumulate in the food chain.

Estimates of the level of exposure to MSW incinerator emissions can be improved by direct measurements of contaminant concentrations in air, soil, plants, livestock, and other media near an operating facility. Such data are usually unavailable, and it is therefore almost always necessary to rely on models to estimate contaminant concentrations in the relevant environmental media. This requires an understanding of the rate and extent of chemical degradation and bioaccumulation in the environment.

In this paper, the uncertainties in estimating chemical degradation and accumulation in the environment are discussed. Examples of the uncertainties in predicting environmental concentrations of chromium and polychlorinated dibenzo-p-dioxins and dibenzofurans are highlighted to illustrate the difficulties that may be encountered in assessing the risks posed by incinerator emissions.