STOCHASTIC INDICATORS FOR WASTE SITE CHARACTERIZATION

Site characterization is an important prerequisite of risk assessment and remediation strategies. Evaluation of the health effects of ground water and soil contamination depends on the adequate analysis of spati al heterogeneity, exceedance levels, and uncertainties. In this work w e formulate and calculate stochastic indicators that provide a rigorou s characterization of exposure levels in sites with heterogeneous cont aminant distributions and offer valuable information for a cost-effect ive cleanup analysis. These site indicators are general and can be use d for different types and distributions of groundwater and soil contam inants. Important properties of the stochastic indicators are examined which can evaluate the potential for contamination at large scales, a nd improve understanding of threatened and damaged ecosystems. Analyti cally tractable formulas are derived that allow the practical estimati on of site indicators on the basis of experimental data. Scale and mod eling effects on contaminant level analysis are examined in terms of t he stochastic indicators. Site cleanup costs depend directly on inferr ed characteristics of the stochastic indicators, which thus can play a n important role in waste site management. Applications are discussed that offer insight regarding certain aspects of stochastic site charac terization. Analytical methods of site characterization are compared t o numerical simulations. It is shown that the latter can provide a pra ctical alternative to the former, but they could lead to inaccurate re sults if they are not interpreted carefully.