The Pamlico River has seen its share of algal blooms because of nutrient-rich runoff, but none in recent history have had the state warning people to keep themselves, children and pets out of the water.

That’s the case in the Chowan River, which threads north to south through a rural eastern North Carolina landscape, emptying into the Albermarle Sound. Since July, blue-green algae has been clogging the waterways, turning the water a vibrant shade of green and causing fish kills in and around the Albermarle Sound.

On Friday, the North Carolina Department of Environment and Natural Resources, recently renamed North Carolina Department of Environmental Quality, sent out a press release warning that the Chowan/Albermarle algae is the cyanobacteria Microcystis aeruginosa, which contains microcystin, a toxin that can be harmful to humans and their pets. Though the state had been testing the water throughout the summer, it was only last week that it tested positive for the toxin.

“While it is safe to boat or fish in the affected areas, the N.C. Division of Public Health routinely encourages the public to avoid contact with large accumulations of the algae and prevent children and pets from swimming or ingesting water in an algal bloom,” reads a statement from NCDEQ.

Exposure to the toxin can cause abdominal pain, nausea, vomiting, diarrhea, sore throat, dry cough, headache, blistering of the mouth, atypical pneumonia and elevated liver enzymes in the serum, as well as hay fever symptoms, dizziness, fatigue, and skin and eye irritations is something that Pamlico-Tar Riverkeeper Heather Jacobs Deck believes everyone should know about.

“There was a lot of media about it a month ago. … But now they’ve confirmed that the testing has come back as toxic,” said Pamlico-Tar Riverkeeper Heather Jacobs Deck. “Really, you don’t want to be out in it — especially your kids, but also your dogs. … Dogs are especially susceptible because it attacks their nervous system.

Deck said the toxic bloom is caused by a confluence of events: a wet spring that sent plenty of nitrogen-rich runoff from agricultural land into the Chowan, compounded by the heatwave in early June that caused the algae to proliferate. Deck said the situation is similar to conditions often seen in the Pamlico.

“These algal blooms are obviously a symptom of the nitrogen. It’s really interesting — we’ve had algal blooms on the Pamlico but nothing as tremendous as what’s happening on the Chowan,” Deck said, adding that fishermen’s reports of little catch in the Pamlico River this summer are likely related: high levels of nitrogen contribute to algae growth, which consumes oxygen when it dies off.

“We’ve had pretty extensive low-oxygen levels, especially in the bottom waters,” Deck said. “Fish will leave if they don’t have oxygen. They’ll seek better waters.”

Deck said nitrogen-rich runoff is hard to handle from a management standpoint, as there are so many sources.

“The human lesson is we still have a lot of work to do to get a handle on our sources of nutrient pollution,” Deck said.

NCDEQ warns people who come into contact with algal blooms to wash thoroughly; if a child appears ill after contact, seek medical attention; and if a pet appears to stumble, stagger of collapse after being in a pond, lake or river, seek veterinary care immediately.