COST-BENEFIT ANALYSES AS BASIS FOR DECISION-MAKING IN ENVIRONMENTAL RESTORATION

An approach is presented for the integrated assessment of clean-up options at contaminated sites. It is applicable to complex environmental situations, such as those frequently encountered at uranium mining sites with a mixture of radiological and non-radiological contaminants present. The methodology presented can also be applied to other problems in the area of environmental restoration where the decision-making about clean-up measures is faced with a variety of risk components affecting humans and the environment. The approach is based upon a quantification of risks to humans and ecosystems caused by radiological and chemical contaminants. Human health risks are expressed as a loss of life expectancy. This concept is directly applicable to lethal health effects such as cancer. For non-lethal health effects from toxic substances, the deterioration of the quality of life is evaluated and combined with the lethal risks into the common assessment parameter ”mean effective loss of life expectancy ” (MEL). This parameter is converted into an equivalent monetary value as the basis for a cost/benefit analysis. Damage to ecosystems, in particular surface water systems, and resources (drinking water) is similarly expressed in monetary terms, based on the societal willingness and ability to pay for the prevention or mitigation of ecological damage. On this basis, clean-up options can be assessed in terms of their benefits in relation to the effort, i.e. financial expenditures, required. Uncertainties in the basic data and assumptions are taken into account using probabilistic simulation techniques (Monte Carlo simulations). The approach establishes a basis for rational and transparent decisions about clean-up measures. The described approach has been developed and tested with regard to concrete situations, par-ticularly in connection with the clean-up at uranium mining sites in Saxony and Thuringia. The paper describes and discusses the methodologies employed and gives a concrete example from the uranium mining reclamation program carried out by WISMUT GmbH