Bacteria levels are often high after heavy rains or storms.
With beach season underway, North Carolina's water quality experts this week started more frequently monitoring recreational waters to ensure they are free of bacteria that can cause illness.
N.C. Recreational Water Quality staff tests coastal sites weekly between April 1 and Sept. 30, checking to see if levels of the enterococcus bacteria, which can be found in the guts of warm-blood mammals, is present. When a test comes in above 104 bacteria per 100 milliliters of water or a 30-day average is above 35 bacteria per 100 milliliters, the environmental agency warns the public to stay away.
In 2017, there were 23 alerts or advisories issued, with six coming in New Hanover County, five in Beaufort, four each in Carteret and Pamlico and one apiece in Brunswick, Currituck, Dare and Onslow counties. Often, those incidents are tied to heavy rains or storms.
"The main cause that we've seen in North Carolina for swimming advisories is stormwater, " said Erin Bryan-Millush, an environmental specialist in the N.C. Department of Marine Fisheries' water quality area. "Typically, areas that are placed under advisories are near stormwater outfalls or adjacent to those areas."
When single-sample tests come in at elevated levels, Bryan-Millush added, the alert is typically for a single day. Having elevated average samples leads to a longer advisory because there must be two samples below the 35 bacteria standard for it to be lifted.
In Wrightsville Beach, five alerts or advisories were issued last year. Tim Owens, the town's manager, said that while there have been improvements made in recent years, heavy rains can still cause sewage to reach Banks Channel from the many outfalls that flow into it, thus leading to the issuance of an advisory advisory.
"In hindsight," Owens said, "you'd design it a different way, but this stuff's been in the ground for 80 years, probably."
Several businesses have in recent years, Owens added, installed concrete that keeps stormwater from reaching the town's pipes so quickly. Such a project is underway at Hanover Seaside Club.
Rachel Noble, a distinguished professor at the University of North Carolina Chapel Hill's Institute of Marine Sciences, is part of a team that's trying to make decision makers' jobs easier.
While currently sampling patterns catch elevated levels if the regular tests come after rainfall, the UNC method would allow the state to be proactive. The method considers the rainfall, nearby bodies of water and infrastructure, including the amount of pavement, and use it to alert users the water body should be closed.
The system has been tested in Beaufort, Dare County, Southern California and Virginia, and, Noble said, "It's been working pretty well so far."
Sewage pollution can impact both aquatic and human life. For the ocean-going creatures, Noble said, the sewage can make the water murkier, making it more difficult for fish to feed, while also impacting oysters' water filtration.
If found, the enterococcus indicates other dangerous bacteria are likely present. Humans who choose to swim in contaminated water can get diarrhea or stomach cramps from campylobacter or salmonella that are often present alongside the indicator bacteria.
"The good news is that the majority of the things you can pick up from swimming in sewage-contaminated water are short-lived," Noble said. She added that those with other illnesses may be at higher risk for longer or more severe bouts of illness if exposed.
Steps the state takes to warn would-be swimmers away from the water include posting large signs indicating elevated bacteria levels in the area and issuing press releases. Staff also calls nearby businesses or camp directors to warn them of the findings.
Bryan-Millush, the environmental specialist, said that while it is hard to tell whether people are heeding the warnings, they do show they're reading signs by dialing the phone number painted there.
"We do get a good amount of phone calls. People are inquiring, so that's good," Bryan-Millush said. "Education is always the best way."
Reporter Adam Wagner can be reached at 910-343-2389 or Adam.Wagner@GateHouseMedia.com.