Suppose a particular contaminant is at an environmental concentration that results in a 10–4 lifetime cancer risk to an individual, but the contaminant has a half-life of 1000 years. Describe how you would estimate risk and present risk information about (1) the risk to one person, (2) the risk to the current population, and (3) the risk to future generations (or everyone ever exposed to the contaminant). Does risk accumulate over time? If so, how would you determine when this risk becomes acceptable?