Toxic Algae Blooms Becoming More Common

HARWICH – Toxic cyanobacteria algae blooms in local ponds are becoming a more common occurrence. In the past couple of weeks, outbreaks have occurred in the West Reservoir and Sand Pond.

On July 31 the conservation department posted a warning sign at Sand Pond.

“For your safety, people and pets should not swim, recreate, or drink water in the waterbody,” the warning read. “The town of Harwich will remove the signs when the hazard dissipates.”

Conservation Administrator Amy Usowski said that the West Reservoir was the hardest hit location over the past couple of weeks. But a week ago there was a mat of the blue/green algae floating about the public swimming beach at Sand Pond. Usowski said she learned of the conditions July 30, and the caution notice was posted the following day.

The mat of blue/green algae in Sand Pond is relatively small, she said, and its location is directed by the wind. With the prevailing southwest breeze, the mat is often located on the northeast side of the pond. But it also has been located near the public swimming beach when the wind shifts.

Ponds on the Cape have been experiencing more frequent cyanobacteria toxic algae blooms in recent years due to increased nutrient infiltration from septic systems, road runoff, and fertilizer use adjacent. People should not swim or allow pets to get near the water when toxic blooms are occurring, Usowski said.

If people come in contact with the algae, they should shower as soon as they get home, she said. She suggested people monitor their children and pets to look for skin irritation and digestive disturbances.

The conservation department, the Association for the Protection of Cape Cod (APCC) and the Massachusetts Department of Public Health (MDPH) are monitoring water bodies, according to Usowski. MDPH this year set up an online reporting system and APCC copies MDPH on its findings. She said people with questions relating to the algae blooms can contact the conservation department or APCC.

“Unfortunately it’s not unusual for this time of year,” Usowski said of the blooms.

Blooms in the West Reservoir have become a common annual event, said Usowski. There is a need for additional study of the water body to gain a better understanding of what is causing the outbreaks, she added.

“Such extensive blooms are not good for the creatures living inside the pond,” said Usowski.

Sometimes the blooms go away, and other times they return. The West Reservoir blooms every summer for anytime from a few weeks to over a month, according to Usowski. Fish kills have occurred, but so far not this summer.

According to Usowski, earlier this summer Buck’s Pond in the Great Sand Lakes section of town had a minor detection of cyanobacteria, but it was not considered a bloom. It dissipated in a couple of days, she said.

Over the years the town has treated water bodies that have had cyanobacterial blooms. Long Pond was treated with alum 15 to 17 years ago after several algae blooms and fish kills. Usowski said Long Pond has done well since it was treated. Hinckley Pond was also treated with alum several years ago and has not seen a bloom since. Last fall Skinequit Pond was also treated with alum and monitoring results have been positive, she said