. . . 2. A small community gets its water from wells that tap into an old, large aquifer. Recently an environmental risk assessment study found toxic concentration in the ground water due to improperly disposed chemicals from a near by manufacturing plant. Estimates are available of the contamination levels of the various chemicals. Each contaminant's concentration (C) in the water is measured in microgram per liter. The Cancer Potency Factor (CPF) for each chemical is uncertain. The population risk assessment must account the variability of body weights (BW) and volume of water consumed (WC) by the individuals in the community per day. A simple equation including all these factors for calculating population risk (PR) is given as : PR CPF X CX WC BW X CF Using the table given below, identify the expected, median and maximum population risk. And also determine the 90% confidence interval for the number of people at risk out of a population of 1 million. Parameter Distribution Min. Max. Mean/Mode STD Concentration of contaminates (C), mg/liter Triangle 80 120 110 CPF Lognormal 0.03 0.02 Water consumption (WC), Normal Liter/day 2 Body Weigths (BW), kg Normal 70 10