- The Washington Times - Monday, April 12, 2004

Officials with the Washington Aqueduct said yesterday federal guidelines prohibit them from changing the disinfectant used to treat the District’s water supply, even though scientists now say the chemical might have caused lead contamination.

The aqueduct in November 2000 replaced pure chlorine with chloramine, a compound of ammonia and chlorine, in a move mandated by the Environmental Protection Agency (EPA). Scientists say the switch might have upset the chemical balance of the water and made it more corrosive.

“We can’t go back to free chlorine and remain in compliance with EPA regulations,” Thomas P. Jacobus, general manager of the aqueduct, said yesterday. “If it is true that chloramine has caused the lead problems, we didn’t know it at the time. Nothing in the literature indicated it would happen.”

Scientist Marc A. Edwards and EPA representatives said the switch might have led to the accelerated corrosion of service lines in the District, first shown in 2001 and 2002 monitorings conducted by the D.C. Water and Sewer Authority (WASA).

“The old plan for controlling lead leaching … had been working reasonably well,” said Mr. Edwards, a scientist from Virginia Tech and a former EPA subcontractor. “Then, a series of events that included a switch to chloramine triggered a ‘perfect storm’ of lead corrosion.”

Excessive leaching of lead to water occurs when corrosive water contacts plumbing materials such as lead pipes.

Mr. Jacobus said the decision to change the disinfectants was made to comply with revised EPA regulations. Chloramine reacts less strongly to organic matter than pure chlorine, he said, causing fewer potentially cancer-causing byproducts.

“The EPA reduced the minimum allowable level of disinfectant byproducts in the water supply from 100 parts per billion to 80 parts per billion,” Mr. Jacobus said. “We had to comply.”

Earlier this month, WASA began testing contaminated residences to find out whether a change in the chemical composition at the aqueduct, not the lead-based service lines themselves, is the real cause of the lead contamination.

Officials have switched back to pure chlorine until May 7 and are testing whether the change in chemicals will affect residences with elevated levels of lead contamination.

“It’s a ‘before and after’ comparison,” said Richard Rogers, chief of drinking water for the EPA’s Mid-Atlantic Region. “The people at WASA are looking to see how the lead service lines react with various components in the water. We want to find out if there’s one particular cause of the elevated lead levels. The results will be a piece of the puzzle.”

Mr. Rogers said the EPA has not yet decided on a plan if tests show that chloramine caused the lead contamination.

“We can’t really say for sure at this point what we will do,” he said.

The city on June 1 will add a new chemical to the water supply to fight the corrosion.

“It will be some kind of orthophosphate,” Mr. Jacobus said. “We’re meeting this week to decide which one.”

Mr. Jacobus said adding an orthophosphate into the water supply is the best thing the aqueduct can do under federal guidelines.

“We believe we can continue to comply with the EPA while reducing corrosion,” he said.

He also said the results of this month’s testing might prompt WASA to stop replacing lead service lines throughout the city.

“If the lead pipes are not contaminating the water, there is no scientific or chemical reason to replace them,” Mr. Jacobus said. “The city could suspend its replacement efforts. But WASA might continue replacing lead pipes for social, managerial, or political reasons. It’s not my decision.”

Mr. Edwards said it is highly likely that adding orthophosphate to the aqueduct should have a positive effect. He said many other utilities that draw water from the Potomac River already use orthophosphates to reduce the corrosiveness of the water.

He also said the EPA should reconsider its guidelines for controlling disinfectant byproducts.

“Limiting potentially harmful byproducts … is a relatively new priority, placed above stringent control of lead leaching in the EPA hierarchy,” Mr. Edwards said. “There’s strong scientific evidence suggesting that disinfection byproducts may cause cancer, and the switch to chloramine at the aqueduct was therefore done with the best of intentions, but the law of unintended consequences has given new life to some very serious problems that were once thought to be solved.”

Mr. Rogers said the EPA’s strict chemical byproduct rules are not intended to prioritize one form of consumer safety over another.

“We want everyone to be healthy,” he said. “You really can’t weigh these concerns against each other.”

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