This thesis examines the groundwater testing that has been done for atrazine in order to describe the way in which this testing might have underestimated human exposures to atrazine-contaminated drinking water. Federal and state pesticide regulations, descriptions of chemical and non-chemical weed control techniques, information regarding atrazine use, and a description of Rhode Island agriculture serve as background information.

The private well testing performed by the Rhode Island Department of Environmental Management was insufficient to support the conclusions made that pesticides do not present a health risk to those drinking water from those wells. There are numerous examples where exposure to atrazine may have been underestimated. Some of these examples also apply to testing for public wells in the state.

Atrazine use should be reduced based on 1) Rhode Island law which requires state agencies to look for alternatives for pesticides, 2) the presence of atrazine-resistant weeds in some areas of Rhode Island, and 3) the measurable levels of atrazine in groundwater in most areas where it is used. Government research should focus on non-chemical alternatives to atrazine, and on improvements in reducing the potential movement of atrazine into groundwater.