SOUTH BURLINGTON -- The Champlain Water District (CWD) is changing the way it disinfects its water in order to make it safer to drink. Beginning April 10, CWD will switch from using "free chlorine" to a "chloramines residual." The switch will affect the water used by about 68,000 people in 12 municipal water systems in Chittenden County, including South Burlington, Shelburne, Williston, Essex, Essex Junction, Winooski, Milton, Jericho Village and most of Colchester.
The change has been in the works for four years. As Mike Barsotti, CWD's director of water quality and production, explains, it's being made for two reasons. First, chloramines are a longer-lasting disinfectant than chlorine and don't dissipate as quickly within the vast water-distribution network. Second, using chloramines reduces the total number of disinfection byproducts by 40 to 60 percent. Disinfection byproducts, which can be dangerous to human health, are created when a disinfectant reacts with naturally occurring materials in the water. The Safe Drinking Water Act requires public water systems to reduce their amount of disinfection byproducts. The U.S. Environmental Protection Agency considers chloramines the "best available technology."
Like chlorine, chloramines -- made by combining chlorine and ammonia -- are added to water used for drinking, cooking, cleaning and bathing to protect against biological and microbial growth. Chloriminated water also doesn't have the smell or taste of chlorine.
But the change does have downsides, Barsotti says. For one, water treated with chloramines cannot be used for kidney dialysis because chloramines are toxic in the bloodstream. The digestive system breaks down chloramines, which makes them safe to drink, the CWD notes. However, CWD and the Vermont Department of Health have been in contact with the dialysis unit at Fletcher Allen Health Care, which has already modified its water system to accommodate the change. Other dialysis clinics and patients have also been notified.
A second concern, Barsotti explains, is that chloramines are toxic to fish. Unlike chlorine, which dissipates from water when it's exposed to the air for several days, chloramines linger for weeks. As a result, aquarium owners, fish stores, restaurants and fish markets that now treat for chlorine -- in both saltwater and freshwater tanks -- will need to start using carbon-filtration systems or other water treatment products.
Otherwise, the EPA and the state health department both consider chloramines to be the safest and most cost-effective way to disinfect water. According to Barsotti, chloramines have been used in other public water systems around the country as far back as 1908. Today, it's added to the public water systems in Boston, Philadelphia, Miami, Minneapolis, Los Angeles, Dallas, Houston and Washington, D.C.
"These are very large population centers we're talking about," says Barsotti. "It's not really controversial."
However, as in the recent debate over the use of fluoride in Burlington, not everyone is satisfied by the government's safety assurances about chloramines. Ellen Powell, a South Burlington resident and a recipient of CWD water, says she's deeply concerned about the use of chloramines, in part because of its potential impact on lead levels in her tap water.
When Washington, D.C., switched over from chlorine to chloramines, thousands of homes showed lead levels in their water that far exceeded the federal limit of 15 parts per billion. Excessive lead in the human body can cause serious damage to the brain, kidneys, nervous system and red blood cells, and is particularly dangerous to pregnant women and young children. According to the Washington, D.C., Emergency Information Center, water filters had to be shipped to 23,000 homes with lead in their service lines.
A similar problem arose in Greenville, North Carolina. Two unrelated children, both under the age of 4, showed blood-lead levels at least 150 times higher than what's considered medically acceptable. That problem was eventually traced back to the water supplier's recent switch to chloramines.
Bill Bress, a state toxicologist with the Vermont Department of Health, says this problem has already been foreseen and addressed. He explains that the chlorine in the Washington, D.C., water supply prevented the corrosion of lead solder in the pipes. Once the chlorine was removed, lead levels began to spike. Bress says this problem will be ameliorated by CWD adding zinc orthophosphate, an anti-corrosive agent, to the water. In addition, Bress says, CWD will continue monitoring for elevated lead and copper levels. "That water system is excellent," Bress says. "Their staff really knows what they're doing."
Still, Powell isn't convinced. She claims that no epidemiological tests have been done on the human health effects of chloramines, and she points to a number of incidents around the country when people or their pets have had adverse reactions to chloramines-treated water, including skin and respiratory problems. And in September 2004, a scientist at the University of Illinois at Urbana-Champaign discovered a disinfection byproduct in chloramines-treated water that he called "the most toxic ever found."
Several local environmental groups have expressed an interest in the chloramines issue, including Vermonters for a Clean Environment, the Conservation Law Foundation and the Vermont Public Interest Research Group. However, none has taken a formal position for or against it.