Exposure and Place: Considering the Historical Dimension of Risk. Craig E. Colten, PHR Environmental Consultants, Inc., Washington, DC 20005
Exposure to hazardous substances is the result of many interrelated processes. Certainly, degree-of-hazard, concentration and public policy are key components of understanding risk. Yet, for most environmental exposures, duration plays a critical role. Risk assessment has not fully addressed this element that demands an understanding of patterns of residential/workplace persistence and also personal mobility. The historical analysis of human mobility suggests that many of the "at risk" populations minimize their exposure by virtue of their impermanence at any single place. Likewise, industrial mobility has transferred many high-risk activities to previously unaffected places. This paper will examine human exposure to hazardous substances as a product of various historical and geographical processes. It will argue that risk is not merely a function of degree-of hazard or management strategies. Rather, risk is contingent upon these things and also a broader historical context that offsets public policy through its own dynamism.