Source: Wisconsin State Journal (Madison, WI), March 22, 2011
Posted on: http://envfpn.advisen.com
With more contaminants being found in city wells, the Madison Water Board is considering a tougher approach to pollutants, including heightened monitoring, filters and other treatments.
Contamination of Madison’s public drinking water wells by industrial pollutants is a growing problem. For example, pollutants are a thorny issue in Well No. 15 on the city’s East Side, and recently the possible carcinogen chromium-6 was found in all but three of 16 operating wells tested for the metal.
Madison is not alone. Lee Boushon, who heads the public water section for the state Department of Natural Resources, said other cities face increased contamination of their drinking water and are considering more aggressive regulatory approaches.
The issue has become more pressing, Boushon said, because new technologies allow detection of contaminants such as chromium-6 at much lower levels. And arriving at agreement on monitoring and treatment is more difficult because unlike bacterial contaminants, which can make people ill immediately, many of the pollutants at issue can cause illnesses, such as cancer, only after years of low-level exposure. The exact level of risk, he added, is much harder to pin down.
“The question now is not really whether water is safe,” Boushon said. “It is whether it should be safer. And that’s much tougher.”
The issue in Madison has taken on urgency with the emergence of chromium-6. After a national environmental group found the contaminant in a Madison water sample, the utility conducted tests of 16 active wells and found levels as high as 1.79 parts per billion, though most were lower than 1 ppb. Because of recent studies that link chromium-6 to cancer, the federal Environmental Protection Agency is considering regulating the metal, for which there is no current standard.
Tom Heikkinen, general manager for the Water Utility, said a standard for the contaminant is likely. California is considering setting a health goal for the pollutant of 0.02 ppb.
But Madison’s water also is plagued by other contaminants, especially a class of pollutants called volatile organic compounds, or VOCs. These are industrial contaminants that include chemical solvents or cleaning agents made from petroleum products. One of these, a carcinogen called tetrachloroethylene, or PCE, has been found in seven Madison wells. While most of the wells have levels less than 1 ppb, testing in 2009 showed Well No. 9 had an average level of 2.1 ppb and Well No. 15 tested at 3.7 ppb. Both wells are on the city’s East Side.
The presence of the contaminants also is a growing concern among some residents. Recently, more than 40 people attended a public information meeting on the VOCs in Well No. 15.
The EPA set the maximum contaminant level for PCEs at 5 ppb. The utility would be required by law to take action to reduce a contaminant when it exceeds the maximum level for a certain period of time. But the utility has no policy on how or when to deal with contaminants, especially carcinogens, when they are below the maximum level but still present.
That’s why the question now arising is whether the utility should take action even earlier, perhaps when the level of the pollutant reaches another threshold called the maximum contaminant level goal — a level set by the EPA below which there is no known or expected risk to health.
Currently, for example, the utility is involved with neighborhood groups working to come up with a plan for a new well and other possible changes for the city’s Isthmus and near East Side areas. Heikkinen said a big part of that discussion is the fate of Well No. 15, which has PCE levels far above the EPA’s health goal of 0. For all carcinogens, the health goal is set at 0 by the EPA — in other words, the goal is to have no trace of the substance in the water.
More than likely, he added, the utility will end up installing a treatment system on the well.
But instead of dealing with such situations on a well-by-well basis, some Madison Water Board members, including Madeline Gotkowitz, a hydrogeologist with the state Geological and Natural History Survey, are urging the utility to adopt a more uniform policy.
She suggested the utility at least prepare a plan for each well that exceeds the health goal for many contaminants known to have long-term health effects.
Heikkinen said the real challenge in establishing such a policy is deciding what levels of a contaminant merit treatment.
“One of the biggest challenges we face,” Heikkinen said, “is communicating about risk. When you set a number or a standard, people think that sort of becomes a dividing line between safe and unsafe. But what that really represents is a continuum. … There is no such thing as absolutely pure water, just as there is no such thing as pure air.”
Heikkinen said one possibility might be doing cost-benefit studies if contaminants show up in Madison drinking water at levels higher than health standard goals set by the federal Environmental Protection Agency. Such studies would compare the increased cost of monitoring and treatment with the health risk posed by the pollutant.
The uncertain risks as well as the potential cost of treatment during difficult budget times add to the complexity of the discussion being undertaken by the water board. More monitoring and treatment are expensive. Joe Grande, water quality manager for the utility, said treatment for VOCs and chromium-6 could run as much as $1 million per well.
Regardless, most agree the conversation is important and worth having. Greg Harrington, chairman of the water board and a UW-Madison environmental engineer, said he expects the board to vote on a new policy in coming months.
“I’m glad we’re talking about this,” Gotkowitz said.