Mysterious Brown, Circular Plume in New Jersey Bay Worries Residents, Lawmakers and Activists

— -- A large brown plume recently spotted in Barnegat Bay near popular beach town Seaside Park, New Jersey is worrying residents, lawmakers and environmental advocates.

The circular, brown mass was initially flagged last Wednesday by nearby beachgoers who initially fled, thinking sewage was draining into the bay, according to Britta Wenzel, the executive director of environmental advocacy group Save Barnegat Bay.

Wenzel told ABC News the concern was brought to the attention of the state's Department of Transportation, which was responsible for installing nine pumps along the bay and Route 35, which is under reconstruction after Hurricane Sandy devastation.

"I need to be crystal clear on this, the water coming from the pump on 8th Avenue was most certainly not sewage," DOT Commissioner Jamie Fox said in a statement. "The Department of Environmental Protection (DEP) and Ocean County both tested the water and found it safe. The public’s health and safety is always our first concern."

The pumps, which are supposed to drain storm water to prevent flooding during reconstruction of the Route 35, apparently had a temporary problem and was just releasing a "a combination of silt built up in the system from the months of construction activity in the area and silt from the bay floor that was turned up by the force of the water exiting the outfall pipe."

The New Jersey Department of Environmental Protection's (DEP) preliminary testing of the water found that levels of potentially harmful bacteria, including fecal coliform and E.Coli, were "very low," according to a DEP report published online.

But Wenzel said Save Barnegat Bay is doing their own independent testing of the water and should have results soon to independently confirm the DEP's report.

She added that the group says residents in the area have noticed that the pumps in the bay are constantly discharging water, not just during storms.

The continuous pumping of water into the bay is worrisome to Wenzel, she said, because no one knows exactly what sediments and other bacteria or stagnant water could be coming into the bay, which was the subject of a 10-point plan Gov. Chris Christie created in 2010 "to address the ecological health of the 660-square-mile Barnegat Bay watershed."

"The bay has a long history of nutrient pollution from lawn fertilizer runoff," she said. "This causes eutrophication, which is too much green stuff growing too fast, and since they don't have lifespans, they die, decay and create low dissolved oxygen conditions in the water, which makes it difficult for animals like clams, crabs, muscles and fish to live.

"And now, these sediments coming into the water could prevent light from reaching the bottoms, so that these animals can also continue to survive," she said.

State Sen. Bob Smith and Assemblywoman Grace Spencer, both Democrats who run the state legislature's joint environment committee, told ABC News today that they are now working with Wenzel and Save Barnegat Bay to get full transparency from the DOT.

"We're drafting a joint communication to the commissioner as we speak asking for a full explanation of the reasons for the plume and what the DOT is doing about it," Smith told ABC News today. "People at a hearing recently also expressed that the pumps into the bay are going constantly on and off, and whether that's coming from rain or infiltration from the the sandy soil is something we're going to ask him. We want a thorough detailed response to our questions."

He added, "We're following up on this to make sure the people of this area are safe and not exposed to dangerous chemicals."