Editors' Summary: Pfiesteria piscicida, a sometimes toxic microorganism, is responsible for the death of millions of fish in Delaware, Maryland, North Carolina, and Virginia. Although the problem of Pfiesteria-related fish kills is associated with the Mid-Atlantic region, other toxic microorganisms have threatened fish and marine wildlife throughout the world. Scientists attribute this "global epidemic" of toxic microbes to excessive nutrient loading from nonpoint sources of pollution.

Water scarcity is no longer a threat, it is a reality. Increasing populations throughout the country and the world are putting increased pressure on existing supplies of freshwater. Cities, states, and regions are scrambling to find solutions to this burgeoning problem. The impact of drought, which has been felt not only in the typically dry Southwest, but also in the humid Southeast this past summer, compounds the problem. So, what mechanisms evolve to help alleviate the problem?

Through the post-World War II era the U.S. Congress, by an incremental process of experimentation and error, developed the knowledge and experience that led to the imposition of individual permits based on uniform technology-based effluent limitations to regulate industrial water pollution. The resulting permit system has gradually reduced the amount of industrial pollution that enters our national waterways.

Agricultural biotechnology has generated much debate about the environmental consequences of field trials and commercialization of transgenic crops. Thus far, the debate has focused on opponents' claims of alleged risks presented by transgenic crops and the proponents' responses to those asserted risks. To date, three issues have dominated the debate:

. the risk of gene flow;

. the risk of weediness; and

. the risk of insect-resistance.

In recent years, the western states have often struggled with the federal government over control and management of natural resources, particularly water. For its part, federal law defers to states in many matters of water resource allocation.

Editors' Summary: In 1989, a National Research Council study concluded that contaminated sediments are "widespread in U.S. coastal waters" and have "potentially far-reaching consequences to both public health and the environment." A 1996 interim EPA report reached a similar conclusion. This concern over contaminated sediments is not new. It has manifested itself in a dizzying array of statutory and regulatory restrictions on the disposal of these sediments.