SANDISFIELD — A holding tank for water used to test the integrity of a new pipeline here was responsible for a spike in contaminants, forcing the pipeline company to haul about 547,000 gallons of it to a wastewater treatment plant in Maine.

Water drawn from Lower Spectacle Pond in Otis State Forest to pressure test four miles of a natural gas spur will be trucked to a Clean Harbor facility in Portland that is approved to treat it, according to Kinder Morgan spokesman David Conover.

Hydrostatic pressure testing is required for all new pipelines before they can flow gas or oil. But before the water is released, its contamination can't exceed certain levels set by the federal Environmental Protection Agency, under which Tennessee Gas has its permit to discharge water.

Kinder Morgan subsidiary Tennessee Gas Pipeline Co. had originally planned to release the water into an upland area after drawing it into pipes in the Massachusetts portion of the company's 13-mile Connecticut Expansion Project.

But after September pressure tests, the water had higher levels of lead, copper, iron, nickel and zinc when compared to water samples analyzed before the tests began.

Levels of tetrachloroethylene were also higher than before the water was used.

In this case, the company attributes the spike to a water storage tank.

"The elements were present in the tank used to store the water prior to testing it for discharge," Conover told The Eagle in an email.

So in a late September filing with the EPA, the company said that it had hired industrial water treatment outfit ProAct Services Corp. to build a system on site in an attempt to reduce contaminant levels.

It appears that did not work.

"In an interim basis they transferred the water to tanks on site and tried to treat it," said Peter Czapienski, a spokesman for the Massachusetts Department of Environmental Protection. "But the water would not meet the prescribed levels in the general permit."

Czapienski, who works in MassDEP's Western Regional Office, said that after the company weighed its options it decided to truck the water out.

Hydrostatic pressure testing was just one aspect of the pipeline project that worried environmentalists and residents of the remote wilderness area of Otis State Forest and Lower Spectacle Pond.

While the EPA requires before and after water analysis for a range of chemicals and heavy metals, there were concerns about erosion and what unknown, untested-for chemicals in the new, 36-inch pipes might leach into the water before its release.

Jane Winn, executive director of Berkshire Environmental Action Team, said she was relieved that the water was being sent away, and glad the company performed water quality tests. In 2014, Winn had written the state's Executive Office of Energy and Environmental Affairs about what might come out of the freshly laid pipes, but also about erosion, even from a controlled water release.

"I'm really glad they had to haul it off," she said. "The risk of erosion was pretty high."

Clean Harbors, which is approved to accept the contaminated water, is a national environmental cleanup and management firm that works with Fortune 500 companies. According to Time Magazine, the company was estimated to pull in around $300 million from cleanup of the 2010 Deepwater Horizon oil spill in the Gulf of Mexico.

Heather Bellow can be reached at 413-329-6871 or @BE_hbellow