Triggers that are not yet well understood can cause this type of algae, called Microcystis aeruginosa, to produce a cyanotoxin that can, in large concentrations, harm people and animals.
After biologists with the N.C. Division of Water Resources confirmed the algae’s presence last week, they shipped samples off for testing to determine whether the toxin was present. The results showed a “moderately low” level of toxin in the lake.
“If you were exposed, the chance of health effects such as a rash would be moderately low, meaning not very likely, but precautions are still the same regardless,” said Carmine Rocco, director of the Haywood County Health Department.
Those precautions are to stay out of the water where algae are visible, make sure that nobody ingests the water and immediately rinse any skin coming into contact with the toxin in fresh water.
Children and dogs, both of which tend to enjoy playing in shallow water, are especially vulnerable. Any person or animal that appears ill after being in the water should seek immediate medical care.
Boating and fishing on Waterville Lake are still OK, however.
In his 10 years with the health department, this is the first time Rocco has dealt with this type of algal bloom. Warm weather statewide has spurred the algae’s growth, with its presence also confirmed in the Albemarle Sound and Chowan River in the eastern part of the state. In addition to cooler weather, heavy rain that causes movement in the water could cause the bloom to diminish, Rocco said.
So far, that’s what appears to be happening.
“We are going out on a daily basis to check on the location of the algae bloom, whether it’s getting larger or smaller,” he said. “At this point it appears to be getting smaller.”
Algae are typically a beneficial part of the ecosystem, supplying food for aquatic animals. However, algae can become harmful when hot temperatures and calm water combine with nutrient-rich waters to produce blooms big enough to produce toxins and consume large amounts of oxygen. When algae causes especially low oxygen levels in the water, fish kills can result. So far, none have been reported at Waterville Lake.