EXr GUEST EDITORIAL Bad news, good news The good news on lead is that environmental exposure is in rapid decline as a result of EPA‘s action to reduce the lead content of gasoline. Blood lead levels, the common measure of exposure, have declined dramatically. The bad news is that the importance of drinking water as a source of lead has grown. Lead enters water supplies as a result of corrosion of solder, flux, and pipes in service connections (or, rarely, interior plumbing), and corrosion is now the largest controllable source of exposure to lead in the United States. Lead exposure is associated with such adverse health effects as mental retardation in children, interference with fetal development, and high blood pressure, heart attack, and stroke in adult men. This summer, EPA will propose a new maximum contaminant level for lead that is below the current standard of 50 ppb. In the meantime, water suppliers, health officials, plumbers, and the public need to c o o p erate to reduce the risks posed by contamination. Corrosion control is the best tool for immediate reductions in the amount of lead in tap water. Simple, inexpensive steps can help dramatically. In Boston, for example, many homes have lead pipes, and the water supply is naturally corrosive. The lead content of water there has been reduced significantly, at a cost of about $0.50 annually per person, by raising the pH of the water. operators of small water systems may find that treatment with lime contactors is a practical, “low tech” approach. Where the water chemistry is unusually complex, more sophisticated corrosion control techniques are necessary. Additional steps, such as increasing alkalinity or treating the water with phosphates, can be taken. Water suppliers faced with particularly corrosive water should begin pilot studies now to help identify the precise combination of methods and additives necessary to ensure that water delivered at the tap has low lead levels. There is an added benefit. Water treatment helps prevent the release of lead into water, but it also usually saves suppliers and customers money in the form of reduced maintenance costs, because pipes last longer when the water they deliver is less corrosive. Corrosion control will help remedy existing lead contamination. And in June 1986, to prevent the spread W13936W87K)9210515M1.59/0 @ 1987 American Chemical Sociefv
of the problem, Congress banned the use of solder or flux with more than 0.2% lead and it banned pipe that contains more than 8%. Effective state implementation of the ban, paired with diligent corrosion control, can reduce much of the lead problem. Although water sup pliers have little if any direct control over plumbing materials, they need to work closely with those who can ensure that lead-free products are used. Given the widespread occurrence of lead in drinking water and the severe health consequences associated with exposure to lead from all sources, it is important that strong, effective steps be taken now to reduce the amount of lead in drinking water. In addition to revising the maximum contaminant level and setting new monitoring requirements, EPA has developed an extensive outreach program that includes a handbook, Lead and Your Drinking Wirer: These steps will help reduce future exposure and can offer advice to citizens on what they can do to help themselves. We hope that the water supply industry will join with us by pursuing those parts of program they are best qualified to manage: corrosion control treatment, a ban on lead plumbing materials, and strong public outreach.
Michael B. Cook is the direcfor of EPAs Oflce of Drinking Water He also coordinates EPAs efforts 10 deal with dioxin in the air. on land, and in w t e r Envimn. Sci. Tmhnol.. Vol. 21. NO.6. 1987 515
