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Government and People
C. T. "Kip" Howlett, Jr., Executive Director
Chlorine Chemistry Council°
Before the Council of the District of Columbia
March 17, 2004
Good afternoon Madame Chair and members of the Committee on Public Works and the Environment. I am Kip Howlett, Executive Director of the Chlorine Chemistry Council, and a Vice President of the American Chemistry Council. The Chlorine Chemistry Council is a national trade association based in Arlington, Virginia representing the manufacturers and users of chlorine and chlorine-related products. Safe drinking water is a vital issue for CCC's member companies, who supply chlorine both for water disinfection, and to manufacture PVC pipe used in modem water infrastructure.
I appreciate this opportunity to speak to the Committee today. I cannot offer any definitive answers on what is causing high lead levels in some District homes, or provide an easy solution. However, I can offer some important insight on the riskbenefit tradeoffs involved. The ultimate solution is to get the lead out, while taking necessary interim steps to protect public health.
Steps taken to reduce one risk must not increase other, more serious risks
As this committee well knows, safe drinking water is one of the most fundamental elements of public health protection. However, water treatment and safe distribution is a complex process, and water systems face a vast array of regulations, competing demands and treatment options. Measures taken to improve one aspect of water quality inevitably impact other aspects.
With the current lead contamination crisis, EPA, the Washington Aqueduct, WASA and the City Council face a number of challenges in balancing public health concerns. Will additional corrosion control measures, particularly the use of zinc orthophosphate, fully resolve the problem? Has the existing lead service line replacement program actually worsened corrosion? If chloramines are indeed exacerbating lead contamination, what would be the health and regulatory implications of switching back to free chlorines for secondary disinfection, at least temporarily?
EPA has recognized the importance of risk-benefit tradeoffs in setting drinking water standards. For example, EPA carefully crafted rules to reduce potential risks from disinfection byproducts without compromising protections against hte far greater risks of microbial contamination. The Agency was well aware of a catastrophe that occurred in Peru in the early 1990s, when exaggerated fears about disinfection byproducts led officials to reduce chlorination. Inadequate disinfection of drinking water supplies contributed to a five-year cholera epidemic, the disease's first appearance in the Americas in the 20th century, that caused more than one million illnesses and 12,000 deaths. Current EPA standards limit disinfection byproduct levels in drinking water with a substantial margin of safety. As a new EPA study issued March 4th concludes, alternatives to chlorination may actually form higher levels of unregulated but potentially more tragic byproducts.
These examples highlight that any decision to change treatment methods must consider overall impacts on microbial quality, chemical parameters, and distribution system impacts. It is critical that steps taken to reduce one risk do not increase more serious ones.
Chlorine is essential to delivering safe water
In 1997, Life magazine hailed drinking water chlorination as "probably the most significant public health advancement of the millennium." Before cities began routinely treating drinking water with chlorine (starting with Chicago and Jersey City in 1908) typhoid fever killed over 25,000 U.S. residents every year. Cholera, dysentery and hepatitis A posed similar threats. Drinking water chlorination has helped to virtually eliminate these diseases in the U.S.
Meeting the goal of clean, safe drinking water requires a multi-step approach. Disinfection, unquestionably the most important step in water treatment, is carried out in two stages, primary and secondary disinfection. Primary disinfection removes harmful microorganisms at the treatment plant. Although a number of alternatives are available, chlorination is by far the most common method.
Chlorine is also used for secondary disinfection, which provides a residual level of disinfectant to help protect treated water as it travels to consumers' taps. Regardless of the primary treatment method used, EPA requires water systems to maintain minimum residual levels of either chlorine itself (free chlorine) or chlorine-based compounds such as chloramines, in the distribution system.
Chloramines are an increasingly popular choice for secondary disinfection
In November 2000, the Washington Aqueduct switched from using free chlorine to chloramines for secondary disinfection. The switch enabled the system to reduce the formation of certain disinfection byproducts regulated by EPA, while maintaining protection against waterborne disease.
Treatment plant operators form chloramines by applying a specified amount of ammonia to drinking water, in addition to free chlorine. Chloramine compounds are more stable than free chlorine. They provide durable protection in long distribution lines, making them excellent for secondary disinfection. Chloramines also control coliform bacteria and biofilm growth on pipes, and are sometimes used to address taste and odor problems. Because chloramines are less reactive than free chlorine, using chloramines can reduce the formation of some disinfection byproducts.
Chloramine use is not new. Denver, Colorado, for example, has used chloramines since 1917. However, its popularity has increased dramatically in recent years, as drinking water systems work to comply with a range of new EPA standards, including the 1998 Stage 1 Disinfectants and Disinfection Byproducts Rule.
Currently, about 30% of U.S. water systems use chloramines as secondary disinfectants. As a result of newly proposed regulations (the Stage 2 Disinfectants and Disinfection Byproducts Rule), EPA predicts that an additional 3% of water systems will shift to chloramines.
As with any significant change to treatment practices, switching from free chlorine to chloramines can pose challenges for a water system. The potential effects of chloramine use on distribution systems and household plumbing are not fully understood.
Did the switch to chloramines cause DC's high lead levels?
Too many open questions remain to say definitively what caused the excessively high lead levels in some DC homes. I share the Committee's hope that the expert team assembled by EPA, WASA, and the Washington Aqueduct will shed new light on these issues and recommend both short and long term solutions.
As has been discussed, the primary sources of lead in drinking water are components of the distribution system itself - lead pipes, lead-based solder, and brass fixtures that contain lead. Given the difficulty and expense of removing all sources of lead, EPA's Lead and Copper Rule is intended to minimize corrosion through appropriate treatment techniques, and prevent these metals from leaching into the drinking water.
Clearly, the use of chloramines changes water chemistry, and such changes can have dramatic effects on corrosivity. The addition of ammonia at the treatment plant increases the level of nitrification in water, which can lower pH in the distribution system. Such a change requires an effective corrosion control program. It will be for others to determine why corrosion control measures here were apparently ineffective for the Washington, DC system, and what changes in water treatment are needed now.
High lead levels in drinking water pose clear dangers to public health, and these dangers must be considered on equal footing with other potential risks from drinking water contaminants. Changes to water treatment methods can affect microbial quality, chemical parameters, and distribution systems. Therefore, decision makers must have the flexibility to balance these competing concerns, and take actions to minimize overall health risks.
Thank you for the opportunity to speak on this issue today.
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