Determining exposure and biochemical effects in human population studies.

We all are surrounded by and exposed to many chemicals in our personal environment. These chemicals are either naturally occurring or man-made. Such exposures may have profound impact on our health, such as cigarette smoking, excessive alcohol consumption, and abuse of illicit and legal drugs, or they may be necessary for our survival, such as nutrients, disinfectants, fertilizers and fuels. However, this is not what will be discussed here. We are concerned about chemicals which have inadvertently contaminated the environment because of the way they were used and disposed of, such as pesticides and other industrial chemicals. Of all the chemicals produced in industry, only