Here, it was pointed out that 80 percent of diseases in the developing world are water related, 4 billion to 7 billion people will face water scarcity in 2050, and water has become a priority issue for economic development throughout the world. The chemical sciences were called upon to address issues such as sanitation (the number-one means of reducing disease), water management (including use of innovative technology), and national water strategies. Other challenges mentioned include the shift of water use from agricultural to industrial applications; accessibility of water supplies; and dilemma of who pays for the treatment, transportation, and infrastructure necessary to deliver water to end users.
There was discussion about getting bright young scientists and engineers more interested in the world’s water problems. It was suggested that the water issue lacks a “glamour factor” and that although the world’s water concerns are great, there does not appear to be a major driver for attracting the best and brightest toward this fundamental problem that impacts every individual.
It was noted that developing countries currently have the opportunity to avoid the mistakes of the developed world. Instead of following the model of “develop first and clean up later,” they might “leapfrog” with current and new technologies. A number of examples in which current technologies are far superior and can minimize the impact on water resources were provided.
Another key point raised involved the water-energy balance. It was pointed out that it takes energy to produce or transport water to the areas that are in need, and that current population densities in the arid and semiarid regions, the water-intensive nature of both agriculture and industry, and the sources and uses of water are all at the crux of this balance.
A number of places where green chemistry will eliminate the use of hazardous reactants (potential water pollutants), conserve water, and increase both the quality and the quantity of pure water were discussed. In one example, a systems approach is being used in industrial water treatment to protect infrastructure from corrosion, scaling, and bacterial growth with the use of more benign chemicals at lower levels. Another example highlighted the use of unique catalysts that are making hydrogen peroxide an economical and viable replacement for chlorine as an oxidant in a number of processes. Praise was also given to closed-loop systems that eliminate the use and contamination of water. It was noted that such systems are now in place for photographic film processing.
This session concluded with a look at mercury, the leading environmental contaminant that often results in consumption advisories for fish in the United States and around the world. Sources of mercury emissions in the environment, biological processes that transform mercury to the more biologically available methylmercury, and chemical conditions that favor such transformations were described. It was suggested that greater understanding of the true toxicological impacts of mercury is needed, and concern was raised about the way in which wetland restoration projects have been carried out. Such efforts, it was noted, can actually increase the presence of methylmercury in the environment.
In this session, technical approaches to analysis and treatment of water problems were discussed by Thomas E. Hinkebein, National Desalination Roadmap Program manager and manager of the Geochemistry Department, Sandia National Laboratories; Richard Luthy, Silas H. Palmer Professor of Civil and Environmental Engineering Stanford University; and Elias Greenbaum, corporate fellow and research group leader, Oak Ridge National Laboratory, and professor of biological physics, University of Tennessee.
The link between population growth and stresses on water supplies was emphasized. It was pointed out that significant growth is taking place in areas with limited water supply. Since 54 percent of the U.S. population lives within 60 miles of the ocean, often in a marginal environment, it was suggested that the opportunity exists for development of viable desalination water sources. However, without a clear plan for the future, it was predicted that water supply issues will limit growth, rely on case-by-case government support, and cause more conflict between states that have water and those that do not.
Challenges of desalination were discussed within the context of the jointly developed Desalination and Water Purification Technology Roadmap of the Bureau of Reclamation and Sandia National Laboratories. This roadmap serves as a strategic research pathway for desalination and water purification technologies to meet future water needs. Near-term and long-term objectives were discussed and included extending existing technologies, requiring technology breakthroughs such as reducing capital costs, increasing energy efficiency, reducing operating costs, and reducing cost of zero liquid discharge processes. It should be noted that in the time since this workshop was held, the National Research Council’s Water Science and Technology Board has reviewed the roadmap (see Appendix D).
Detection of organic contaminants (especially compounds that are persistent, bioaccumulative, and toxic [PBTs], such as polychlorinated biphenyls [PCBs]) in water and in sediments was also discussed during this session. Details of work on mitigating the effects of contaminants in sediments and reducing the risk to health by decreasing the bioavailability of the chemicals were described. This work involves adding carbonaceous material to sediments to facilitate binding of contaminants. It was explained that these treatments may be superior to dredging, which is planned for PCBs in the Hudson River.
The types of analytical tools and bioavailability tests now