Assume a factory releases a continuous flow of wastewater into a local stream, resulting in an in-stream carcinogen concentration of 0.72 mg/L just below the outfall. Suppose this carcinogen has an oral potency factor of 0.45 (mg/kg-day)-1 and that it is degradable with a reaction rate coefficient k of 0.23/day. To keep the problem simple, assume that the stream is uniform in cross section, flowing at the rate of 2 mph, and that there is no other sources or sinks for this carcinogen. At a distance of 150 miles downstream, a town uses this stream as is only source of water. Estimate the individual residential lifetime cancer risk caused by drinking this water.