A pond in South Portland’s Hinckley Park has tested positive for a type of algae that produces toxins that can be fatal for dogs.

New signs posted around the pond in South Portland’s Hinckley Park warn of algae that could be toxic to pets. Photo courtesy of South Portland Parks and Recreation Department

The South Portland Parks and Recreation Department posted warning signs Friday based on testing results that showed a blue-green algae bloom could possibly produce the same toxins that have killed pets in other states this summer.

“We are asking that people please keep your dogs away from the shorelines. Don’t let them drink the water, swim or go near the algae that is accumulating on the shorelines,” the department wrote in an initial Facebook post Thursday evening.

Along with posting signs around the pond Friday morning to warn dog owners to keep their dogs away from the water, the city posted a new message on Facebook urging park visitors to pick up after their dogs because the feces left around the pond contributes to the algae problem.

“The signs have been posted at Hinckley Park, near main entrances and along the water’s edge. We will be sure to post again when we have new information about changes in water conditions,” the post says.

“We would also like to take this time to point out that one cause of this bloom is from an excess of pet waste that is left behind in our park. We need park visitors to pick up ALL pet waste and dispose of it in proper receptacles. Failure to comply with our parks rules and regulations could result in an unfavorable change to those rules and regulations.”


The new signs posted in Hinckley Park also ask pet owners to be sure to remove waste, which can contribute to algae blooms. Photo courtesy of South Portland Parks and Recreation Department

Blue-green algae growth, known as cyanobacteria, is made up of microscopic organisms that naturally occur in streams and lakes. Much of it is harmless, but it can produce toxic chemicals that cause sickness in people and can be fatal to dogs.

Scott Williams, executive director of Lake Stewards of Maine, a volunteer lake monitoring program, said blue-green algae has been found in what he called “moderately high” levels in a handful of lakes out of thousands across the state.

“It’s not unusual to find some cyanobacteria, even in the clearest lakes,” he said. “Algae is a normal component – it’s the base of the food chain – but it’s really only a problem when the concentration rises.”

Williams said the two things that contribute to higher levels of blue-green algae are temperature and phosphorus levels, both of which are tied to climate change. Higher temperatures warm bodies of water and soil erosion creates runoff that contains phosphorus.

Williams said he wasn’t aware of the algae bloom in South Portland – his organization doesn’t track that water body – but said public ponds are more likely to be susceptible to water quality issues.

A good rule of thumb for people, Williams said, is to never drink untreated water. As for whether lakes are safe from algae blooms for swimming, he said if you can wade out to your shoulders and look down in the water and still see your feet, the water is almost certainly safe.


“We’re fortunate that this isn’t a major concern here in Maine,” he said. “But it’s something to be aware of.”

The Maine Department of Environmental Protection lists lakes at risk of algal blooms on its website, but that list does not note if any of those blooms are ongoing. The Lake Stewards of Maine also share its water quality data online.

At least four dogs have died this summer in North Carolina and Georgia after swimming in water contaminated with blue-green algae, The Associated Press reported.

Blooms of blue-green algae have been documented in all 50 states, David G. Schmale III, a professor at Virginia Tech, told CNN.

Dave Maker was glad to see warning signs posted at Hinckley Park when he stopped by Friday afternoon with his pitbull, Debris. While Maker lives in Alfred, he visits Hinckley Park weekly because he has friends in South Portland.

“I love this park,” Maker said. “I’m glad they put up signs. My dog is my life. I wouldn’t let her swim in something toxic.”

Staff Writers Eric Russell, Kelley Bouchard and Megan Gray contributed to this report.

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