We discussed in clаss the cаse оf the recent sewаge spill in the Pоtоmac River. Based on this discussion and the course material, answer the following questions: a. Give 3 contaminants that are likely to be found in sewage and be a thread for the environment. b. For each of the contaminant, indicate which is the mechanism by which it constitute an environmental thread. c. For one of these contaminant and a potential target organism, indicate what are the likely route(s) of exposure and sites of action, metabolism, and excretion (you may not know for sure, but you can make a guess).