Six years later, the state has still not built the new system, and inmates, their advocates, and environmental scientists worry that the drinking water is unsafe.
A Globe review of state records found that 43 percent of all water samples collected at MCI-Norfolk since 2011 showed elevated levels of manganese, a prime component of the sediment from the wells.
In December, the Norfolk Inmate Council, which represents prisoners, reported that nearly two-thirds of inmates responding to a survey said they had suffered rashes and other skin problems.
Asked about the elevated levels of manganese, Peter Lorenz, a spokesman for the state Executive Office of Energy and Environmental Affairs said, “More than half the water samples are within compliance.” In an e-mail, Department of Environmental Protection officials said the prison was in “compliance with MassDEP requirements for addressing this type of issue.” The prison aims to follow the US Environmental Protection Agency’s health advisory for manganese, which recommends that people drink water with levels below 0.3 milligrams per liter over their lifetime.
“I think it is a concern,” he said of the samples, which the prison collects and provides to him in special bottles.
“It is more than likely that the allowable levels of manganese in water will decrease as we learn more about its effects on the brain.” Birgit Claus Henn, a Boston University epidemiologist who has spent years studying the impact of manganese on people, said the water system should have been repaired if even 10 percent of samples showed elevated levels of the mineral.
“If the state isn’t meeting that 40 percent of the time, that’s a problem.” State public health officials, after learning from the Globe that many of the prison’s water samples had elevated levels of manganese, said they would consider reviewing the inmates’ concerns.
The new plant “will have the ability to filter out iron and manganese and should minimize any discolored water in the future,” Christopher Fallon, a spokesman for the Department of Correction, wrote in an e-mail.
He denied the allegation that the prison gives bottled water to the dogs in the training program.
Prolonged exposure of elevated levels can be harmful.