One of the land bank’s Island jewels, Ice House Pond near Lambert’s Cove, was briefly closed over the weekend, due to suspected contamination with human waste.

The pond was closed on Friday afternoon, but reopened again on Sunday after testing revealed no bacterial contamination of the water.

Matthew Dix, the property foreman for the land bank, said the decision to close the pond was taken after a swimmer alerted staff on Friday afternoon that she had spotted something floating near the access dock.

“Someone went down there and thought it looked like human waste. She called me, we asked people to leave and took a water sample.

“We didn’t know for sure what it was, or what the source might have been.

“But the results came back on Saturday, and the water was fine. It was re-opened Sunday morning,” he said.

It was the first time the pond had been closed, Mr. Dix said.

“It’s a restricted pond. Obviously we don’t allow any kids who can’t swim on their own. So there are no little toddlers or babies in diapers. Maybe it was vandalism, maybe someone was incontinent. It could have been an animal too.”

He said the land bank was particularly cautious about the management of the pond, because of its environmental sensitivity. It is a glacial kettle pond, which means there is no natural flushing mechanism, so any contaminant which gets into the water tends to stay there.

The pond was only opened to the public last year, after considerable controversy involving abutters and conservationists.

Tight restrictions were applied to its use. A maximum of 20 people may be there at any one time. Access is by a single path and boardwalk to protect the fragile pond edges, and rare flora and fauna.

No dogs are allowed in the water, swimmers are encouraged to use rest rooms before entering the water, and sunscreens, soaps and shampoos are banned.

“We like to play it safe because it’s a nature preserve first and foremost,” said Mr. Dix.

“Last year was our first season. The hardest part of the job is that there have to be so many rules. But there have never been any problems before. Hopefully there won’t be any more,” Mr. Dix said.