Since July, the Hanover Department of Public Works has received more than 100 complaints about brown, sometimes smelly, tap water. The water has rusted out sink fixtures, ruined clothes and linens, and turned dishware orange.
In response, town officials have made 93 house calls at residences in north Hanover, taking water samples and checking them at a local lab. Although the lab is not state-certified, and the results were not official, technicians found elevated concentrations of manganese in the water samples. Officials, though, say the water is safe for consumption and there’s no cause for alarm.
Manganese is associated with the manufacture of fireworks and munitions. However, Victor Diniak, director of the Hanover Department of Public Works, said the discolored tap water had nothing to do with the National Fireworks Co. site in south Hanover, where the Department of Defense and Rockland-based National Coating Corp. manufactured various munitions, nor with a site where the Massachusetts Institute of Technology dumped toxic waste.
“Manganese is prevalent in ground-water sites throughout New England,” Diniak said in a phone interview. “All ground water in New England has some traces of manganese, and some traces of iron.”
A year ago, the state considered recommending the site for Superfund status, which would mean the federal government would take charge of the cleanup, but the label would also have marred the area’s reputation and meant the town would relinquish control of the cleanup effort. State and local officials are hoping that the three responsible parties — the Department of Defense, National Coating Corp., and the Massachusetts Institute of Technology — will come to an agreement soon about how to divvy up the financial burden of the cleanup, which is estimated to cost $28 million.
Joe Ferson, a spokesman with the state’s Department of Environmental Protection, said researchers analyzed soil and ground-water samples from the site in 2009, and manganese was “determined to not be a contaminant of concern.” He agreed that the Fireworks site had no relation to manganese in the water.
Officials recently invited 300 north Hanover residents to a meeting at which Town Manager Troy Clarkson underscored this point by saying “discolored water does not equal bad water.”
State and federal guidelines recommend that drinking water contain less than 300 parts per billion of manganese. While adults can tolerate as much as 1,000 ppb over a short-term period, young children absorb more of the element, and should not consume more than 300 ppb.
According to Neal Merritt, Hanover’s water superintendent, samples taken in Hanover have shown manganese levels varying from tap to tap. In July, when the water department responded to 11 calls, the average concentration of manganese was 356 ppb. Five of those samples were at or below the 300 ppb standard, and the highest reading was 720 ppb.
Manganese is not considered carcinogenic, and trace levels of manganese are ingested as part of a regular diet. However, some studies suggest that too much of the chemical may affect the nervous system, and that young children who are exposed to high levels of manganese may suffer from learning- and behavior-related problems.
In August, 34 complaints were called in. The town took samples from 22 of those households, yielding an average concentration of 305 ppb, with 12 samples below the 300 ppb level, and the lowest reading at 41 ppb and highest at 900 ppb. In September, the levels were back down below the maximum guidelines, with 29 samples averaging 227 ppb.
“The numbers have been coming down consistently since July,” said Merritt. “It was very erratic, and wasn’t consistently above 300 for any significant duration.”
Discoloration and odor in tap water can be caused by as little as 50 ppb of manganese, which is well below what is considered the maximum of exposure.
According to Diniak, it’s not unusual to get a few calls about discolored water every summer when there is more demand on the system, though the number of complaints this year have been significantly higher than normal.
Because Hanover’s water system is a network of several aquifers, high demand in the summer months can cause water to flow with more force or travel through different pipes to meet demand. Diniak believes the manganese is the result of sediment in the pipes, which was kicked up this summer after two different pumps malfunctioned and were taken offline, sending water flowing in a different direction to reach houses in the northern part of town.
“When you change the direction of water, it stirs things up,” Diniak said. “Water comes from the ground, and manganese is a naturally occurring mineral. Our water treatment plants clean it as best we can. But there was a time when the treatment wasn’t great, and left sediment in the pipes, which have been around since the 1930s.”
Other south suburbs have also dealt with particularly bad water discoloration this year. In Norton, it lasted for about a week in September during the height of seasonal flushing, according to Town Manager Michael Yunits, who said the problem has since gone away, and the town hadn’t yet set up its manganese testing program before then.
In Scituate, the problem has gotten so bad that in July the Board of Selectmen approved a $22 million water pipe replacement project, which would be funded by a 10 percent increase in the town’s water rate.
Some north Hanover residents at last month’s water meeting said they, too, would like to see a pipe replacement project, and vowed to bring a petition to the next Town Meeting.
Diniak said he did not think the pipes needed to be replaced.
“They can advocate it all they want — I don’t think that’s a good use of money. I don’t think that’s the issue here,” he said. “We had a water break on north Main Street during the height of the problem in August. We expected to see some iron buildup on the pipe and we really didn’t.”
Cara Bayles can ge reached at firstname.lastname@example.org.