The North Carolina Department of Environmental Quality’s Division of Water Resources (DWR) has issued an advisory for the public to avoid contact with green or blue water in Lake Norman due to ongoing algal blooms. These blooms have been present since June 16 and have been observed in various locations across Catawba, Iredell, Lincoln, and Mecklenburg counties. The northeastern parts of the lake have reported higher concentrations.
Investigations by DWR at five sites revealed that the blooms are dominated by Dolichospermum, a type of cyanobacteria also known as blue-green algae. While these blooms often appear bright green, they can change to a milky blue when decaying, potentially producing a strong odor affecting large areas.
Dolichospermum can produce microcystins, toxins that may harm humans and pets. Initial testing on June 17 did not detect these toxins; however, toxin production can vary rapidly. Continuous monitoring is being conducted, with updates available on DWR’s Algal Bloom Dashboard.
The N.C. Department of Health and Human Services’ Division of Public Health advises avoiding contact with significant algae accumulations and preventing children and pets from swimming or drinking affected water. Recommendations include keeping children and pets away from discolored or scummy water, not handling algae mats or dead fish, washing thoroughly after exposure to algal blooms, rinsing pets exposed to such waters with clean water, and seeking medical care if illness occurs after exposure.
Algae naturally occur in all bodies of water but certain conditions like increased nutrients (nitrogen and phosphorus), high temperatures, sunlight exposure, and low water flow can lead to rapid growth resulting in algal blooms.
Reports of algal blooms can be submitted online or through the nearest DEQ regional office. For more information on algal bloom events or health effects associated with them, individuals are encouraged to visit the DWR website or the DPH website respectively.
