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PEMBROKE

Algae forces 2 ponds to close

May open by July 4 after treatment

By Christine Legere
Globe Correspondent / June 16, 2011

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Blue-green algae, consisting of toxic microscopic organisms called cyanobacteria, have shut down two ponds to all recreation in Pembroke, but health officials hope chemical treatments scheduled to be applied yesterday will knock down bacterial levels sufficiently for the ponds to reopen for the Fourth of July.

The algae in Oldham Pond contained cyanobacteria levels more than three times the state-recommended limit when it was closed the second week in June. A few days later, Lisa Cullity, Pembroke health agent, issued an advisory warning against any recreational activity in Furnace Pond, after testing showed levels at double the recommended standard there. The town doesn’t have a public beach on Furnace, but about 200 residents own homes along its shore.

Both ponds normally would have quite a bit of boating and swimming activity at this time of year.

Aquatic Control Technology, a Sutton-based company, planned to treat Furnace Pond with copper sulfate yesterday. The pond received a similar copper sulfate application last summer for algae problems.

Treatment of Oldham Pond will be trickier and more expensive. The Massachusetts Department of Fisheries and Wildlife’s Natural Heritage and Endangered Species Program prohibited the use of copper sulfate, due to presence of a rare mussel in the pond. The agency signed off on the application of Phycomycin, a non-copper-based algaecide highly effective against blue-green algae, but will allow only a third of the pond to be treated at a time. In between treatments, the welfare of the mussel will be monitored.

Cullity said the initial treatment would focus on the area where the algae bloom is heaviest: the northwestern section near Hanson. How and when the rest of the pond is treated will be partially dependent on the effectiveness of the first application.

“The treatment [at both ponds] should give the algae a knockout punch,’’ Cullity said. “We expect we’ll have a couple clean rounds of testing in a very short time, so we’re hoping to have all the beaches open by the Fourth of July.’’

According to the federal Centers for Disease Control, contact with cyanobacteria can result in rashes, hives, and blisters. Inhaling droplets can result in runny eyes, infected sinuses and ears, sore throat, and asthma-like symptoms. Ingestion may cause diarrhea, vomiting, and cramps. Pets have been known to die from ingesting the toxin, and children can become quite ill.

Following the discovery of the algae blooms in Oldham, Cullity did door-to-door canvassing to see whether there had been any cases of adverse physical reaction to the cyanobacteria. “One woman said her two children were throwing up and had diarrhea, after swimming in the pond,’’ Cullity said. “Both also complained of minor headaches, which are all typical reactions. There’s no test to confirm, and the treatment is to stay hydrated.’’

Populations of blue-green algae grow naturally in water bodies and are harmless in small concentrations. Failed septic systems, storm-water runoff, and agricultural operations such as farming and cranberry growing can boost phosphorus in water systems and cause algae growth to explode.

In Halifax, meanwhile, an advisory warning against recreational activity in West Monponsett Pond has been posted by health agent Cathleen Drinan after recent discovery of the blue-green algae near the state boat ramp. The public is being warned about adverse reactions they could experience if the toxins get on the skin or are inhaled or ingested, Drinan said.

West Monponsett Pond was off limits to boaters and swimmers most of last summer and for a portion of the summer before due to the presence of the blue-green algae. “Last year, the numbers on the toxins stayed high right until December,’’ Drinan said. The Department of Fisheries and Wildlife attributed a major fish kill in West Monponsett Pond in 2009 to the algae, she added.

Halifax officials have been ready to treat West Monponsett Pond with a chemical mix of aluminum sulfate since last summer, but are still waiting for the go-ahead from the Natural Heritage and Endangered Species Program. Permission is required because of the presence of the Eastern pond mussel and a rare dragonfly.

“Natural Heritage doesn’t want us to rely on chemicals, so they are asking for a long-range plan to treat the phosphorus in the pond,’’ said Charles Seelig, Halifax’s town administrator. “We’re hoping the treatment of the lake will happen this summer.’’

A third pond in Pembroke is also slated for a chemical application, although not due to the presence of the blue-green algae. Hobomock Pond will be treated with the algaecide Sonar to rid its waters of an invasive plant called hydrilla. The pond can be used within a day or two of treatment.

Pembroke Selectman Arthur Boyles, also a member of the Pembroke Watershed Association, said the town has been proactive in dealing with water-quality issues in its lakes. “We’re ahead of these problems in Pembroke because we have a watershed association, and we have Lisa Cullity, who watches our ponds like she owns them,’’ Boyle said.

Christine Legere can be reached at christinelegere@yahoo.com.