03-28-08: Ducks may be contaminating New Hanover swimming hole

Wilmington -- It might be time to blame the ducks.

A submerged sewer pipe, a suspected culprit of high bacteria counts found near a popular swimming area in Castle Hayne, has been tested and ruled out as a possible contamination source, according to New Hanover County officials.

Engineering firm McKim and Creed tested the line on behalf of Pender County, which owns the line, using both pressure and dye testing techniques. Red dye was inserted into the line on March 12, and engineers have so far not found any indication of a leak.

The 8-inch force main carries wastewater from Pender County to Wilmington's Northside treatment plant on North 23rd Street and runs beneath the Northeast Cape Fear River and Riverside Park, a boating and swimming area popular with residents from New Hanover and Pender counties.

"That takes one of the prime suspects off the table," said Larry Cahoon, a UNCW water quality expert whose graduate student's research found the high levels of bacteria normally found in human and animal waste. "It's good that it's been tested and that it's intact. That's really good news."

Now the most likely cause of the contamination are the water fowls that congregate in the area, Cahoon said. But just because the source may be birds doesn't mean the area is safe for swimming.

"Fecal contamination is still fecal contamination," Cahoon said.

Earlier this month, New Hanover County officials posted signs at the park advising residents not to swim there. On Wednesday, the county posted an additional sign at the boat ramp, said Dianne Harvell, county environmental health services manager.

County health officials regularly sample the waters near Riverside Park, and state environmental officials test waters near the boat ramp on a monthly basis. Researchers at UNCW monitor the area as well.

Besides birds, other possible contamination sources are other animals and nearby septic tanks, Harvell said. Officials are looking to identify any other animal sources, such as pet kennels, and doing further evaluations of some septic systems in the area.

The county also wants to test more frequently as the weather warms and the summer months approach, Harvell said.

If water fowl are the problem, part of the solution could be simple: stop feeding them. Cahoon said ducks and other birds gather there in large numbers in search of human handouts.

Chris Mazzolini: 343-2223

chris.mazzolini@starnewsonline.com