STONINGTON, Conn. -- Environmental scientists are testing the Pawcatuck River because of potential pollution concerns.

Channel 3 Eyewitness News reporter Kevin Hogan reported that swimming in the Pawcatuck River is not encouraged because of pollution concerns.

Starting Monday, the Connecticut Department of Environmental Protection and the Rhode Island Department of Environmental Management began testing the waters for pollutants in the natural border between the two states.

Scientists will check possible pollution outlets, pipes and other drains for higher than average levels of nitrogen and other contaminants.

The marine investigators will work with agriculture officials to test the river from the Route 1 bridge connecting Westerly and Pawcatuck five miles south, where it empties into Little Narragansett Bay in the Long Island Sound.

Hogan said the pollution levels in the offshore waters have elevated, forcing authorities to ban shellfishing.

According to the Connecticut DEP, identifying the pollutant source and taking corrective action will go a long way in cleaning up the river.

Brian Bradley, a local fisherman, saw the scientists on Monday and he told Eyewitness News he agrees that whatever they do will improve conditions for everyone.

"It looks pretty clear. There are a lot of things you can't see, but I would imagine that if the fish are alive, it can't be too bad," he said.

The two states' environmental scientists are working in conjunction with federal agencies in an effort to make the Pawcatuck a designated clean river.

Stay with WFSB.com and Channel 3 Eyewitness News for the latest news updates.