Fear not, Forensic Chemist! You will soon know more than you probably would want to know about the toxins resting in your body.  Like David Ewing Duncan, you will probably be surprised/concerned about the extent these toxins reside in our bodies, but until we learn what is in our bodies, we can't mount an effective response to these noxious molecules.  You will pursue the following tasks in order to form an effective response to these common exposure pathways: