Problems of risk balancing for regulating environmental hazards

Rational regulation of environmental hazards may be based on the implicit underlying principles that government actions should enhance the average quality of life for those governed and maintain some degree of equity in the distribution of benefits, costs, and risks. Issues arising from these principles have practical implications for risk management policy in general and for the development and application of radiological protection criteria in particular. One of the issues is the appropriate distribution of expenditures for regulating different risks. The total resources available for risk regulation are finite; hence, minimizing the total risk subject to this constraint is an appropriate strategy for optimum risk management. Using a simple model, it is shown that this strategy leads to a distribution of expenditures between different risks such that a greater fraction is allocated to a risk with a higher cost of mitigation or control but the allocation is limited in such a manner that the fractional contribution of that risk to the total risk is also higher. The effect of deviating from this strategy is examined. It is shown that reducing a single risk of concern below the optimum value by a factor 1/F can increase the total risk by about F times the risk of concern. Taking into account the large uncertainties in risk assessment for establishing radiological protection criteria, it is argued that an optimum strategy for remedial action should (1) set basic risk limits as high as reasonable; (2) use realistic, case-specific data and analyses in deriving allowable residual contamination levels from basic risk limits; and (3) implement a policy of reducing residual contamination to levels that are as low as reasonably achievable (ALARA) within the constraints imposed by optimum resource allocation. 10 references, 1 figure