Setting human-health-based groundwater protection standards when toxicological data are inadequate.
Toxicological data are not adequate to assess fully the health effects of many of the pesticides that currently contaminate or have the potential to contaminate groundwater. The National Academy of Sciences estimated in 1984 that data to conduct a complete health hazard assessment exist for only 10% of the pesticides currently on the market. Many pesticides have not been tested for their ability to cause cancer, genetic mutation, or birth defects. There are significant gaps in the toxicological data base for the majority of pesticides for which the Environmental Protection Agency proposed health advisories in 1987. To help assure that groundwater standards are adequately protective of human health when toxicological data are not adequate, additional uncertainty factors can be incorporated into such standards. Alternatively, standards can be set at the level of detection. This should be the approach when no data exist to assess major potential health effects. For example, the detection limit could be the standard if no adequate oncogenicity studies have been conducted. In addition, generic standards may be employed when data are inadequate to set chemical-specific standards. New York State has recently taken this innovative generic standard approach.