AN APPROACH FOR BALANCING HEALTH AND ECOLOGICAL RISKS AT HAZARDOUS-WASTE SITES

Human health and ecological risks must be balanced at hazardous waste sites in order to ensure that remedial actions prevent unacceptable ri sks of either type. Actions that are designed to protect humans may fa il to protect nonhuman populations and ecosystems or may damage ecosys tems. However, there is no common scale of health and ecological risk that would allow comparisons to be performed. This paper presents an a pproach to addressing this problem based on classifying all risks (i.e ., health and ecological risks due contaminants and remediation) as in significant (de minimis), highly significant (de manifestis), or inter mediate. For health risks the classification is based on standard crit eria. However, in the absence of national guidance concerning the acce ptability of ecological risks, new ecological criteria are proposed ba sed on an analysis of regulatory precedents. Matrices and flow charts are presented to guide the use of these risk categories in remedial de cision making. The assessment of mercury contamination of the East For k Poplar Creek is presented as an example of the implementation of the approach.