Test Results Indicate High Health Risk from Contact with Chowan River Algal Bloom


The North Carolina Department of Health and Human Services is urging the public to stay out of the Chowan River near Arrowhead Beach because of an algal bloom producing a toxin called microcystin. 

Test results indicate this bloom is producing microcystin at observed levels greater than 250 micrograms per liter. At these levels, officials with the Division of Public Health would consider this bloom a high risk for acute health effects during recreational exposure, based on guidance values published by the World Health Organization (WHO).  

State environmental officials have been monitoring the numerous blooms in the Chowan River since May. On July 17, staff from the Department of Environmental Quality’s Division of Water Resources responded to a reported algal bloom near Arrowhead Beach north of Edenton and will continue to monitor the bloom.

The algal toxin microcystin is produced by organisms called cyanobacteria. Environmental conditions controlling toxin production by cyanobacteria are not well understood and can change rapidly over time and location. North Carolina has had no reports of adverse health effects in people associated with this algal bloom. 

Because of the high microcystin levels, state health officials further suggest the following steps to safeguard children and pets: 

  • 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 that may be present.
  • If you come into contact with affected waters, wash thoroughly with soap and clean water. 
  • Use clean water to rinse off pets that may have come into contact with affected waters.
  • If your child appears ill after being in affected waters, seek medical care immediately.
  • If your pet appears to stumble, stagger or collapse after being near affected waters, seek veterinary care immediately.

For more information on potential health effects from algal blooms, visit the Division of Public Health’s website. To learn more about algal blooms in North Carolina, visit the Division of Water Resources’ website.

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