Chemical Hazards

Learning Goals: Demonstrate the reality of adverse human health effects to chemicals.

Are chemicals in the environment harmful? If you asked this question to the man-in-the-street, most would answer, "Yes, of course." If we asked an "environmental consultant," what is the risk to human health from a trace of chemical X or Y in the drinking water?" he would look in a table, scratch his head, crunch some numbers, and give you some number for the risk. Later in this course we will learn that the scientific basis for those tables is very weak. In fact for the vast majority of "scare" chemicals, there is little or no scientific evidence that environmental exposures have harmed anyone. That does not mean they are not harmful, just that it is hard to prove.

Here are two cases where chemicals have done some harm. First involves a workplace exposure.

Wetterhahnl note the quantities involved. When I first read the account of this tragedy, cynical me thought the researcher was probably sloppy for a long time and only admitted to the one accident. I was wrong. Later investigations of trace mercury deposits in her hair demonstrated that those few drops were all Karen Wetterhahn was exposed to - just a few drops on top of standard lab gloves, just once.

At you will find a description of the Minamata disaster. In this case, all the exposures were via the environment, none of affected persons worked for the company that caused the problem. . The toxicology facts are accurate.

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