ABSTRACT
What are the risks posed by contaminants to humans once they are released? The œrst step to answering this question involves combining the following three factors related to the physical chemistry of the contaminant: (1) toxicity or potency, (2) mobility, and (3) persistence. Next, the composite physical chemistry attributes are considered within the context of a region’s geological vulnerability. This framework provides a powerful tool for assessing the environmental risk of an urban region, but it fails to consider the known risks of release related to speciœc surface activities. In this chapter, we introduce the concept of surface risk, one component of the environmental risk picture within any urban region.
