WILMINGTON — Recent water quality tests at two sites along a stream connected to the Bradley Creek watershed found that levels of fecal coliform — microscopic bacteria used as an indicator for pathogens — were 150 times higher than the level deemed safe by state regulators.
“We don’t know what’s going on yet, since we just got the data,” said Michael Mallin, a UNCW professor and team member of a water quality testing team that reported the results to city officials on Aug. 25. “We don’t know if there is leakage, potential leakage, from any of the sanitary sewer lines.”
On Aug. 25, Mallin emailed a group that included N.C. State professor William Hunt and Wilmington stormwater manager Fredric Royal — he told them fecal coliform levels at two Bradley Creek testing stations were quite high. The tests were performed around two weeks ago, Mallin said.
“Don’t go near the water…,” Mallin wrote in the email.
‘Holy guacamole’
The samples showed that fecal coliform readings clocked in at over 30,000 CFU (Colony Forming Units)/100mL. Mallin said that for waters of Bradley Creek’s classification, N.C. safety standards say that fecal coliform levels shall not exceed a geometric mean of 200 CFU/100mL, “based upon at least five consecutive samples examined during any 30-day period.”
Of the two stations that showed high readings for these microorganisms, one is located near the intersection of Clear Run Drive and Racine Drive, and the other is by College Acres Drive — both close to UNCW campus.
The Bradley Creek watershed encompasses a drainage area of 7.2 square miles, which includes most of the UNCW campus, as well as large portions of Airlie and College Roads. The water system drains directly into the Intracoastal waterway through the Bradley Creek marina. Twenty-seven percent of the total area is covered by impervious surfaces, like concrete, which lends to surrounding pollution, Mallin said. More than 16 thousand people live in the boundaries of the watershed, which has suffered past pollution from sewage leaks, waste from development projects and stormwater runoff, according to Mallin.
Exposure to higher-than-usual levels of fecal coliform can pose a danger to animals who come into contact with the water, and it can also threaten the health of humans, especially if they contact the polluted water with bare feet or open wounds.
These “urban creeks” are upstream from Bradley Creek marina, which serves as the link between an entire tidal watershed and the Intracoastal waterway; the water eventually makes its way to the ICW via the marina.
Mallin said that his team currently tests at four stations in the Bradley Creek watershed, while others have been sampled in past years. The two stations that yielded high readings are located on Clear Run, “the uppermost tributary to the main body of Bradley Creek.” He said of the four stations, these two are continually the most polluted.
William Hunt, an N.C. State professor with experience in testing the quality of Wilmington-area waters, said by nature the water in these creeks flows downstream and could potentially affect the pathogen levels in other zones of the watershed.
In response to Mallin’s reporting of the high fecal coliform levels, Hunt responded: “holy guacamole! Thanks, Mike! Seems pretty obvious what we are trying to clean! haha!”
“It’s not like those things die 100 feet downstream, they’ll continue to flow,” Hunt said. “That is always a concern, that people in the lower parts of Bradley Creek — before it gets to the intracoastal waterway — could also be exposed.”
Hunt said in the water’s process of moving from nearby UNCW out toward the coast, the pathogen levels are diluted, so there’s no indication the excessive fecal coliform levels would be found in the Bradley Creek Marina, or in other watershed stations closer to the coast than those that were tested.
The fecal coliform count at these two specific areas is drastic enough to pose a threat to any human or other animal that comes into contact with the Racine-area streams, said UNCW professor Larry Cahoon.
“That level, I mean hell I wouldn’t let my pets — if you have a dog and that dog likes to get in the water, that’s a bad idea,” Cahoon said. “Rover might get sick but Rover likes to lick himself or herself, and then lick you.”
Hunt said parts of the affected streams are “quite lovely,” and although people don’t usually wander through urban waters, there is always the possibility that people could take their pets into the streams, or walk through them barefoot, which would pose a dangerous threat to their safety.
“As soon as you cross some threshold of general exposure risk, then people need to be alerted,” Hunt said. “If the same readings were being observed in the lower part of Bradley Creek or in the Intracoastal watershed, then it does become incumbent upon the city or any regulating authority to make people aware.”
Wilmington and CFPUA response
According to Anna Reh-Gingerich, interim watershed coordinator for the Heal Our Waterways Program at the city’s Stormwater Services department, when Wilmington is alerted to results like these, the Cape Fear Public Utility Authority is tasked with determining the source cause. As of Sept. 2, that investigation is underway.
“When a monitoring result comes back this high, the City procedure is to reach out to CFPUA to investigate if there is a sewage leak in the area and also perform an internal investigation for an illicit discharge. This is the most likely cause behind such a high value,” Reh-Gingerich said. “Stormwater inputs can also carry Fecal Coliform to our waterways depending on what is happening on the surrounding land and the amount of stormwater entering the creek.”
A spokesperson for CFPUA said that its Environmental Management Department spoke with Wilmington staff about the readings on Wednesday, and on Sept. 2, CFPUA staff were at the sites in question, “collecting its own surface water samples.”
“At this time, we have no indication of sanitary sewer problems in the area,” the CFPUA spokesperson said. “Once results from those samples are available, staff will share them with the City.”
On Sept. 3, the CFPUA showed Port City Daily its test result findings — taken two weeks after Mallin’s — which showed far lower fecal coliform levels than the previous tests. CFPUA’s test showed fecal coliform levels roughly 23 times lower than Mallin’s findings at one station, and at the other station CFPUA reported the levels were roughly 100 times lower than what Mallin found them to be.
There was a two-week interval between Mallin’s testing and the CFPUA tests.
“The results indicate that there is not an active sewer leak in the area,” the CFPUA spokesperson said.
Regarding communicating test results to the public, Reh-Gingerich said: “All of the annual water quality monitoring reports are provided online. The City also mails an annual ‘Stormwater Watch’ newsletter to all City residents with updates regarding the status of all waterways within City limits.”
The city is a partner in two grants relating to the Bradley Creek watershed. Reh-Gingerich said: “One is headed by North Carolina Coastal Federation and is focusing on stormwater improvements at UNC-Wilmington, which is the largest landowner within the Bradley Creek Watershed. The second grant will be implemented by North Carolina State University and will focus on improving the pollution treatment of commercial wet ponds in the University Commons area. This grant was just recently selected for funding and will begin in Spring 2021.”
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