that it contends could reach a conversion rate at which nearly 75 percent of solar energy becomes electricity. German researchers have invented a photoelectrolysis cell that they believe can, with improvements, convert 30 percent of solar energy into electricity to produce hydrogen.
The renewed interest in fission-driven power plants preceded the Bush administration, but the administration’s policies and the current shortages of electricity will add impetus to the relicensing of some existing plants and perhaps interest in building new plants before the end of the decade. However, although the nuclear industry has developed new designs for power plants, issues of materials, safety measures, radioactive-waste disposal, and the negative public view of nuclear power remain formidable barriers to bringing new plants online. The revival of interest in nuclear plants, however, suggests the need to pursue work in these areas, particularly ways to improve disposal techniques for nuclear plant wastes, because some states limit on-site storage within their boundaries, and the federal government has yet to open a national storage site.
Environmental problems did not start with the industrial age, but industrialization did exacerbate them. Understanding and countering environmental threats to human health and Earth’s flora, fauna, air, and water will challenge researchers across many disciplines in the coming decade. Progress in environmental science will depend, in part, on new technologies that enable faster evaluation of chemicals, advances in computational biology, new animals models, better databases, and defining the interaction of environmental factors and genes.
One growing concern is the question of hormone disrupters, or hormone mimics, which are environmental chemicals that evidence suggests may interact with the endocrine systems of humans and animals to cause birth defects and several cancers. A key element in investigating the issue is the need to develop reliable, short-term assays to identify hormone-disrupting chemicals.
Occupational exposure, safe water, and metal contaminants also remain a concern. Although many workers nationwide encounter chemical and biological agents in the course of their employment, the level and risk of exposure for the vast majority remains unknown or poorly defined. Pollutants contaminating water supplies and the use of chlorine pose unresolved scientific and policy questions. “Safe” levels of such contaminants in water as arsenic and the impact of the by-products of chlorination on human illness remain unknown. Metals in the