ABSTRACT
The logical approach to dealing with multiagent exposures is to express health impacts for each agent in terms of a common currency — risk. Risk misconceptions can lead to confusion and public fear and may impair communication. Agent-specific health risks are often not comparable. In a risk-based system it is assumed that a 1:1,000 risk from agent A has the same meaning as a 1:1,000 risk from agent B. Uncertainties in cancer risks reflect substantial difficulties in measuring a small effect in the presence of a large natural burden of disease. Nontargeted delayed effects suggest that risk is fundamentally different at high and low doses, and simple dose extrapolations to predict risk do not adequately account for the complexity of effects in the low-dose range. Reducing doses to levels below background necessitates removing some or all sources of naturally occurring terrestrial radionuclides in addition to all exposures from the anthropogenic sources being managed. .
