GILL — Gill plans to install treatment systems to address long-standing issues with coliform bacteria, manganese and iron in Gill Elementary School’s drinking water supply.

Administrative Assistant Ray Purington said the board recently met with representatives from the Massachusetts Department of Environmental Protection to discuss what contaminants need to be treated in the water, and which do not.

The meeting covered concerns about coliform bacteria, which can indicate whether other pathogens may be present, as well as manganese, iron and arsenic.

Purington said DEP has ordered the town to install a system to treat the water for coliform bacteria, which he said will most likely consist of an ultraviolet light treatment system.

“There have always been on-and-off cases of coliform bacteria, and it’s not necessarily harmful to people,” Purington said. “If there’s any indication of e. Coli, then you chlorinate but we’ve never had that, so it’ll be U.V.”

DEP officials aren’t requiring the town to address elevated levels of manganese and iron, but Purington said the selectmen plan to do so anyway. That will likely consist of an ion exchange filtration system, he said, which won’t leave any residual taste.

The system needs to be in place by the beginning of the 2016-2017 school year, according to a letter to the town from DEP. Purington said early estimates based on similar systems elsewhere show it could cost up to $180,000, but he expects it will actually be much less than that.

The board wants to address the manganese and iron for two reasons, he said: because the interaction of the two in the water can lead to unpleasant taste and odor, and because it can affect the clarity of the water.

“We want people to feel good and be comfortable drinking the water at the school,” he said.

That, and too much manganese can be bad for health, especially for infants. DEP recommends drinking water with less than 0.30 milligrams per liter over a lifetime to avoid possible adverse neurological effects.

The manganese levels in the school’s wells have fluctuated between 0.30 and 0.50 milligrams per liter over the past few years.

DEP isn’t requiring the town to take any action to address arsenic levels, which the town is required to regularly monitor since the wells have historically tested at half the level where it becomes a health concern.

“It’s not of a level where it’s a health concern for DEP, and that’s something we’ve really been trying to stress in our discussions,” Purington said. “It’s a naturally occurring element, and our levels are half of what is considered a concern.”

A second quarter 2016 sample tested above that level at 0.0152 milligrams per liter, but a second confirmation test was below the limit.

“We want to have adequate and acceptable water, and certainly we’ll act on it if there’s an immediate health risk,” Purington said.

You can reach Tom Relihan at: trelihan@recorder.com.
On Twitter, @RecorderTom