Oldham Pond was closed in the second week of June for levels that were three times the state limit for blue-green algae.
“I know it took longer than most people would like, but Oldham Pond is open and it has successfully passed its second test, for a second week in a row, for blue-green algae,” said Pembroke Health Agent Lisa Cullity.
Blue-green algae can cause skin rashes, and if consumed can cause vomiting and diarrhea. Consumed in large quantities, the algae acts as a nerve toxic and can cause serious illness. Cullity said two children were likely sickened in Oldham Pond before it was closed, but recovered quickly.
The pond has been tested it every week since then, and treated with two rounds of the sodium-based algaecide phycomycin. The traditional treatment, copper sulfate, could not be used on the pond because it is home to the endangered eastern pond mussel. Oldham Pond is one of the first to be treated with phycomycin, and one of the first to be treated while containing an endangered species.
“It did take a while, but it seems the treatments have been working…We’re really kind of a pilot program for anyone else that might face this issue of toxic algae in a pond with an endangered species,” said Cullity.
Cullity said they will continue to monitor the algae levels in the pond.
“There’s no guarantee it’s going to stay away, but the levels have been dropping every week, and they’re now below the tolerances that are allowed. If we see any of the levels rising, we’ll take further action that is necessary to make sure they stay low,” said Cullity.