|SREL Reprint #2270|
Estimating Human and Ecological Risks from Exposure to Radiation
Thomas G. Hinton
The term risk analysis is now used routinely in the environmental sciences, with risk being defined as the probability of a deleterious effect. It is the quantitative probability component (e.g., a 1 in 10,000 chance of an event occurring) that separates a risk analysis from a more qualitative assessment of effects. Our abilities to conduct full-scale risk analyses differ greatly depending on the contaminants and organisms of concern. Indeed, most ecological risk analyses lack a probability statement and, therefore, are more accurately defined as assessments.
The primary goal of this chapter is to demonstrate some techniques for calculating both human and ecological risks from exposure to radiation. A few fundamental concepts about radiation are presented first, and then the reader is guided through two examples: a risk analysis for a hypothetical resident of a radionuclide-contaminated Superfund site, and a risk analysis of an exposed fish population. The scientific rigor inherent in the two risk analyses is compared and, although both examples are for radiation exposures, results of the comparison are not atypical for other environmental contaminants.
Exposure to radiation provides a good example because radiation is one of the most studied carcinogens. According to Eisenbud (1973), "....... it is not unfair to say that more is known about this subject than is known about the effects of any other of the many noxious agents which man has introduced into his environment." A large database exists, due in part to the tremendous resources that were made available from the 1950s through the 1970s to study the environmental transport of radionuclides and their effects on humans and biota. The research was driven largely by the need to understand the effects of global fallout from nuclear weapons. Fortunately, the threat of nuclear war has greatly diminished. However, risks from nuclear accidents remain: the legacy of Chernobyl continues to be written as our knowledge of its effects expands. Risk analyses are also needed for making decisions about the cleanup of Department of Energy sites contaminated during the weapons production era. This chapter contrasts the scientific rigor, and thus the general level of confidence, inherent in analyses of human versus ecological risks from radiation exposure.
SREL Reprint #2270
Hinton, T.G. 1998. Estimating human and ecological risks from exposure to radiation. p. 143-166. In Risk Assessment: Logic and Measurement, edited by M. Newman and C. Strojan. Ann Arbor Press, Inc. Chelsea.