Nonpoint source pollution, for example, is one of the greatest and most extensive threats to drinking water supplies, public and private alike. Similarly, emerging contaminants—such as complex compounds resulting from pharmaceuticals—are increasingly being identified in the surface and groundwater supply. They pose new challenges in understanding not only their evolution but their effects on human health.

Finally, it is hard to discuss health issues without thinking about September 11 or the anthrax concerns of 2001. Terrorism adds another dimension to our concerns about water supplies and the potential effects of their contamination, whether inadvertent or intentional, on human beings.

The idea for this workshop emerged from a series of discussions among Roundtable members on key issues now facing the environmental health community. The occasion gives us an opportunity to invite experts to come in and inform us about some of the current conditions, and how well we are dealing with them, and about some of the challenges we are likely to encounter—and had best be prepared for—in the future.

This workshop posed a number of very important questions to help us chart a course for the twenty-first century:

• What are the current and future challenges to ensuring public health as it relates to water issues?

• Where is the disconnection between policy and reality—in particular between water treatment practices and scientific understanding?

• Where is our scientific understanding deficient in its ability to inform water policy?

• Are there additional research needs for agencies that work to safeguard public health?

• What are the barriers to pursuing this research or to achieving the necessary improvements?