The Use of Landscape Chemical Cycles for Indexing the Health Risks of Toxic Elements and Radionuclides

Analysis of energy-system impacts requires quantifications of short- and long-term local, regional, and global modifications. This paper describes and illustrates an approach for assessing long-term health risks due to dispersion of naturally occurring radionuclide series and chemical toxins by normal and altered landscape-chemical cycles. Health hazards are expressed as dose factors which convert environmental concentrations into a corresponding dose field (organ doses in rad for radionuclides; daily intake for toxic elements). The dose field is translated into a population health risk. The external environment is modelled by considering the manner in which elements are distributed and mobilized within the earth system. The landscape prism is presented as a tool for visualizing and mapping toxic material cycles near the crustal surface. An approach is provided for dividing the landscape into a set of compartments consistent with patterns of element circulation observed in the global environment. We investigate the response of regional landscapes to increases of ²³⁸U, ²²⁶Ra, arsenic and lead in soil and groundwater. It is found that each decay series or element imposes a hazard by its behavior in the total environment that cannot be quantified by a simple measure of toxicity.