Blue-green algae are a relatively common occurrence in the Pamlico River’s brackish waters, and its toxicity can be harmful and/or fatal if consumed.

Last week, news outlets reported that two dogs died after swimming in a California pond contaminated with blue-green algae. The same could happen in Beaufort County, and according to water quality officials, awareness is the key to prevention.

“We are entering the period when there is an increased likelihood of algal blooms, including potentially harmful ones. Although we know the factors … it is hard to predict when blooms will occur,” said Harrison Marks, executive director of environmental advocacy group Sound Rivers.

Blue-green algae, known as cyanobacteria, form a greenish, foamy mat along the top of the water.

“There are hundreds of species of blue-green algae. They are usually microscopic, but high concentrations can sometimes be seen with the naked eye,” according to information from the N.C. Department of Environmental Quality’s Division of Water Resources.

These high concentrations, or algal blooms, most often occur in slow-moving or stagnant waters with high concentrations of phosphorus and nitrogen, most often from agricultural runoff in Beaufort County. They are also prone to occur in warm water temperatures.

“Blue-greens are notorious bloom formers. These blooms can cause unsightly water discoloration, surface films, flecks, mats, and taste and odor problems,” NCDEQ information states. “However, there have been no documented cases of health problems caused by blue-green algae in North Carolina.”

Cyanobacteria can produce cyanotoxins during an algal bloom, which can then enter the body through inhalation, ingestion or cuts and sores. Cyanobacteria can even accumulate in bathing suits. Cyanotoxins are what make the algae potentially harmful to people and animals.

When humans or animals are exposed to the toxins, symptoms range from vomiting and diarrhea, headache, fever, and in the case of animals, fatal respiratory paralysis, according to the U.S. Environmental Protection Agency.

“We haven’t received any recent calls reporting potentially harmful blooms,” Harrison said.

Last July, water quality officials were monitoring multiple areas for blue-green algae following a period of hot weather and heavy rains.

“If it looks weird, if it looks odd, don’t get it in. With children, no open scabs or wounds,” Jill Paxson, an environmental senior specialist, said in an interview last year. “If you have dogs that like to go swimming, give them a bath and rinse them off.”

The Division of Water Resources tests water at hundreds of sites throughout the year, looking for high levels of enterococci, bacteria found in the intestines of warm-blooded animals. While enterococci are not harmful, they signal the presence of other, more harmful bacteria in the water.

Although warning signs are posted in areas with potentially contaminated water, it’s up to residents to stay aware and know when to stay away.