Warning issued over algal bloom in Chowan River


Officials with the N.C. Department of Environmental Quality say water samples taken from the Chowan River have identified an algal bloom in the river as Dolichospermum, a member of the blue-green family of algae that starts out green but may change to a milky blue as it decays. The decaying algae also produces a strong, foul odor.


By Miles Layton
Chowan Herald

Tuesday, July 3, 2018

EDENTON — A state agency is warning the public to avoid contact with a bluish-green algal bloom in the Chowan River off Chowan Beach.

Officials with the North Carolina Division of Water Resources issued the advisory Tuesday in response to the bluish-green water that’s lingered off Chowan Beach since June 20. Chowan Beach is about 12 miles upstream from the town of Edenton.

Staff with the DWR’s water sciences program have identified the bloom species in the Chowan River as Dolichospermum, a member of the blue-green family of algae. Dolichospermum typically appear bright green but when the bloom starts to decay, the color may change to a milky blue. The decaying algae also produces a strong, foul odor.

Diane Swanner said she saw algae in the Chowan River on Sunday, four houses south of Arrowhead Beach and within eyesight of Colerain's beach and the mouth of Keel Creek. She described the smell as “awful, like a moldy hamper.”

Despite the smell, there have been no reports in North Carolina of people suffering ill health effects from Dolichospermum blooms.

“Results for algal toxin testing done on samples collected from the Chowan on June 28 came back well below the World Health Organization’s and the federal Environmental Protection Agency's recreational contact guidelines,” said Mark Vanderborgh, a DWR senior environmental biologist.

This is the second time in two years that algal blooms have appeared in the Chowan River. In June 2017, an algal bloom spread from the eastern side of the Chowan River near Arrowhead Beach south to Edenton, before continuing along the shoreline until just beyond the N.C. Highway 32 bridge.

Colleen Karl, spokeswoman for the Chowan-Edenton Environmental Group, said the warm weather plays a big role in the spread of algal blooms.

“Hot, hot weather with no rain is not going to be helpful — we may likely see more pockets of blue-greens developing,” Karl said.

For now, though, the algae in the Chowan River appears to be dissipating around Chowan and Arrowhead beaches, she said.

“It appears the most of the really bad bloom at Chowan Beach from last Friday has dissipated or has blown out to the middle of the river,” Karl said. “Chowan Beach had some algae, but not a serious bloom; same with Arrowhead.”

Edenton's waterways, meanwhile, appear clear of any algal blooms.

“We saw nothing on our slide samples from the town dock although there are a few visible strands of blue-greens in the water column,” Karl said.

State health officials routinely encourage the public to avoid contact with large accumulations of algae. They say children and pets also shouldn’t swim or ingest water from an algal bloom. They also suggest the following safety tips when encountering an algal bloom:

* Keep children and pets away from water that appears bright green, blue, discolored or scummy. Do not handle or touch large mats of algae.

* Avoid handling, cooking or eating dead fish found in algal bloom.

* If you are exposed to water where an algal bloom is occurring, wash thoroughly.

* If a child appears ill after being in water where an algal bloom is occurring, seek medical care immediately.

* Use clean water to rinse off pets that have been exposed to water where an algal bloom is occurring.

* If your pet appears to stumble, stagger or collapse after being in a pond, lake or river, seek veterinary care immediately.