The N.C. Department of Environmental Quality’s Division of Water Resources (DWR) has issued a public advisory to avoid contact with green or blue water in Lake Norman due to algal blooms that have been present since June 16.
Algal blooms have been reported at various locations across Catawba, Iredell, Lincoln, and Mecklenburg counties, particularly concentrated in the northeastern parts of the lake. These blooms can shift location based on wind and wave activity.
DWR conducted investigations at five sites and identified Dolichospermum as the dominant species. Previously known as Anabaena, Dolichospermum belongs to cyanobacteria, also referred to as blue-green algae. While these blooms typically appear bright green, they may turn milky blue when decaying and emit a strong odor affecting large areas.
Dolichospermum can produce microcystins—algal toxins potentially harmful to humans and pets. Rapid tests on samples collected on June 17 did not detect microcystins; however, toxin production is unpredictable and may change rapidly. Monitoring continues, with updates available on DWR’s Algal Bloom Dashboard.
The N.C. Department of Health and Human Services’ Division of Public Health (DPH) advises avoiding contact with large algae accumulations and preventing children and pets from swimming or ingesting water in affected areas.
DPH recommends several precautions:
– Keep children and pets away from discolored or scummy water.
– Avoid touching large algae mats.
– Do not handle dead fish found near blooms.
– Wash thoroughly if exposed to an algal bloom.
– Rinse pets with clean water if they contact a bloom.
– Seek medical care if a child appears ill after exposure.
– Seek veterinary care if a pet shows symptoms like stumbling after exposure.
Algae naturally occur in all waterbodies but certain conditions can lead to rapid growth or blooms. These include increased nutrients like nitrogen and phosphorus, higher temperatures, more sunlight, and low or stagnant water flow.
To report an algal bloom incident, individuals are encouraged to contact their nearest DEQ regional office or submit reports online. Information about reported events is available on DWR’s Fish Kill & Algal Bloom Dashboard.
For further details about algal blooms visit the DWR website. Information regarding potential health effects is available on the DPH website.
