Toxic Algae Bloom Closes Hinckley’s Pond

by William F. Galvin

            HARWICH – A toxic algae bloom has been discovered in Hinckley’s Pond in the Pleasant Lake section of town, and the health department is closing human and pet access to the waters for up to two weeks.

            Health Department Director Paula Champagne said she was notified Friday evening while at home of the conditions discovered through routine testing by the state Department of Environmental Protection. She said testing showed 400,000 cells per milliliter when 70,000 cells is an action-level trigger.     

A pond closure sign is posted to the rail of the Cape Cod Bike Trail across from the Pleasant Lake General Store. WILLIAM F. GALVIN PHOTO

        “I read the CDC (Center for Disease Control) pamphlet and said we have a significant problem here and we need to act,” Champagne said of the concern for exposure to humans and animals.

            The culprit is cyanobacteria, a blue/green algae which is natural to these waters, but not in this density. Champagne could only guess at the nutrients that drove the algae bloom. She cited runoff from heavy rains, temperature, fertilizers and phosphorus as likely culprits.

            “Something has occurred to provide the nutrients to have this kind of reaction,” Champagne said.

            Should humans swallow the water it could cause severe gastroenteritis. Liver and kidney toxicity can occur and make take hours to days to show up. Neurotoxicity can appear 15 to 20 minutes after exposure and cause numb lips, tingling fingers and dizziness. Neurotoxicity in dogs can cause salivation, weakness, staggering, difficulty in breathing, convulsions and death.

            “A few years ago in Nickerson State Park in Brewster there was a mystery over the death of dogs that was traced to this kind of algae bloom,” Champagne said. “Pets play in the water, drink the water, and people may not want their pets out loose during this algae alert.”

            The health department director said after DEP made the discovery, it notified the state Department of Public Health, which notified the Barnstable County Health and Environmental Department. George Heufelder, the director of the county health department, contacted Champagne at home.

            Champagne then contacted Lee Culver, director of Harwich Emergency Management, and they agreed to put together a team and meet at the town’s water department. There they used a telephone alert system to contact people living around the pond, informing them not to swim, fish, wade, boat or allow pets to access the pond.

            The phone system is not perfect, Champagne said, citing the volunteer sign up conditions associated with its use.

She also contacted a former member of the health board who lives along the pond to start a phone tree among neighbors. There are a number of homes along the north side of the pond which operate private drinking water wells, Champagne added.

            Town Administrator James Merriam sought the assistance of members of the division of highways and maintenance, who canvassed areas around the pond that evening and posted closure notices at access points.

            Champagne said she was glad she took the immediate initiative, given the nice weather on Saturday and the amount of people who would have sought access to the pond. She said her department received several phone calls about the posting.

            This is the first time in 20 years of working with the health department that Champagne has had to close a pond because of an algae bloom. But the health director said she can remember responding to one a number of years ago with former fire chief Robert Peterson. She said it looked like an antifreeze spill in one of the ponds. The testing, she said, is a lot more comprehensive now.

            Champagne also wanted to make people aware the closure is not the same as the periodic swimming beach closures caused by excessive bacteria. Those tests are mandated by the state on a weekly basis and closures usually last only 24-hours, or in the case of marine waters, a tidal cycle.  

            There have been algae blooms and fish kills in recent years in Long Pond, which is connected to Hinckley’s Pond by Princess Brook. Those ponds are part of a chain of herring spawning headwaters.

            The town, county and state contributed to a $400,000 alum application to the pond to bind phosphorus, which was believed responsible for those problems in Long Pond. Champagne said an algae bloom will die off and sink to the bottom of the pond, but it will also rob the waters of oxygen necessary for fish survival. There has not been a fish kill in Hinckley’s Pond, but it would not be unexpected, she said.

            Health Board member Dr. Alfred Hurst said on Monday there are also a number of homes along the edge of the pond in the Headwaters section that were built on small lots and whose septic systems may be inundated with pond water.  

            “It’s definitely phosphorus driven,” Frank Sampson, the chairman of the town’s water quality task force said. It is not just the presence of phosphorus, but combined with temperature and the winds of the last week, the bottom may have been stirred up. This is a natural process, he said.

            Sampson said on Monday afternoon he was not ware of conditions in the pond, but the task force was already planning a special study of Hinckley’s Pond this summer using limnologists the town employed in the Great Sand Lakes study.

            “There have been blooms in the past and we’ve been watching it,” Sampson said of Hinckley’s Pond. “If they come up with something we may have to get more aggressive.”

             Champagne said she does not have a date certain for lifting the closure, but they are projecting about two weeks at this time.

7/2/09