Toxic algae in Hinckley Park ponds. Photo courtesy of South Portland Parks and Recreation Department

Cyanobacteria has been identified in the ponds in Hinckley Park in South Portland. Cyanobacteria can be dangerous and deadly to dogs. It can cause stomach illness and rashes in humans. The city has urged residents and visitors to stay out of the water and keep their pets from drinking or swimming in the ponds.

It is recommended that anyone who comes into contact with the water at Hinckley Park washes their hands and anything that touched the water. If a pet has contacted the water, it is recommended to consult a veterinarian.

The Parks, Recreation, and Waterfront Department identified the cyanobacteria blooming in the ponds on July 17. The ponds are expected to be dangerous until sometime in the fall, when the algae will die on its own in cooler temperatures. Warnings have been posted at entrances to the parks and near the ponds. They will be removed when the algae is gone.

Cyanobacteria are photosynthetic microscopic organisms that are technically bacteria. It was formerly known as blue-green algae due to dense growths of the bacteria turning the water blue-green. The algae are found in lakes. According to the Maine Department of Environmental Protection, high nutrient concentrations can result in a population surge and create an algal bloom, especially in warm weather.

Cyanobacteria can create cyanotoxins that can pose a danger to humans and dogs. Since 2008, the Maine DEP has measured cyanotoxin concentrations in Maine lakes. According to the Maine DEP, most lakes in Maine do not create cyanotoxins at concentrations warranting concern, though some lakes experience annual blooms that produce them. Algal blooms will reduce water’s transparency and change the color to ones such as to neon green, pea green, blue green, and reddish brown. Effects of toxicity can depend on factors such as degree of exposure, concentration of toxins, and sensitivity of the individual. Toxins are not readily absorbed through the skin.

The algae has been present in the ponds in Hinckley Park for the past few years. South Portland has placed native plants to stabilize eroding soils on about 450 feet of the lower pond’s eastern shoreline to help inhibit the algal growth. The Parks and Water Resource Protection Departments are also working together on strategic water quality monitoring to investigate if the growth is related to upstream sources of phosphorous such as runoff and fertilizer.

Individuals can contribute to preventing the growth by picking up pet waste, staying on designated trails, and avoiding bare and eroding soils.