Hamilton issues water warning after chemical is found

August 30, 2008 01:45 PM Email| Comments (0)| Text size – +

By Padraig Shea, Globe Correspondent

The North Shore town of Hamilton has warned residents that their water may be tainted with a potentially hazardous chemical. The town of Millbury in the central part of the state, meanwhile, has also shut down one of its wells after detecting unsafe amounts of the chemical.

John Tomasz, Hamilton’s director of public works, said tests taken earlier this month had found perchlorate, which officials say can disrupt thyroid function, in two locations. He warned that pregnant women, nursing mothers, children, and people with thyroid problems should not drink tap water. He said people should also discard any beverage or ice prepared with tap water in recent days.

In Millbury, the Millbury Avenue well was shut down on Thursday, according to a statement from Aquarion Water Co., which operates the well. Citing similar safety concerns as in Hamilton, the company also advised Millbury residents to discard ice and beverages prepared before Friday.

The samples taken Aug. 13 in Hamilton -- at the School Street well and at the Idlewood water treatment plant -- contained as much as 22 times the state limit of 2 parts per billion. New samples taken Thursday and Friday returned clean, Tomasz said. But the no-drink order for children and pregnant and nursing women will only be lifted after six consecutive days of clean samples.

“We’re taking samples every day until Tuesday just to confirm that the water supply on an ongoing basis is OK,” he said.

In Millbury, readings of perchlorate were 10.2 ppb, five times the Massachusetts limit, according to Aquarion’s statement. The company has not received results from confirmation samples. In the meantime, town residents will get their water supply from the Jacques well in town and from Worcester, according to the company.

Joe Ferson, a spokesman for the Department of Enviornmental Protection, said the high readings of perchlorate in Hamilton are being scrutinized.

"They suspect it might be part of the [testing] process. It has happened before. That's why we immediately retest to determine the source and try to eliminate lab error," he said.

Perchlorate is used in explosives and rocket fuel. Exposure to the chemical can cause, among other things, impairment in physical development, behavior, movement, speech, hearing, vision and intelligence, according to the DEP.

While the state has set safety standards for perchlorate, the US Environmental Protection Agency has not ruled officially yet on what level of perchlorate is safe. It has set a nonbinding safety standard at 24.5 parts per billion.

Massachusetts issued its perchlorate regulation -- the toughest in the country-- in 2006 after high levels of the chemical were detected in an aquifer in Bourne. The DEP concluded the chemical had probably originated from nearby Otis Air Force Base. By last year, nine Massachusetts towns had detected excessive levels of perchlorate in their water supplies.

Ammonium perchlorate is widely used in solid propellants for rockets, missiles, fireworks and explosives. It may also be generated by water treatment processes, and sometimes there is no apparent man-made cause, the state Department of Environmental Protection says on its website.