The public is being warned away from two ponds in Henniker after the state determined they contained high levels of cyanobacteria concentration.
Keyser and French ponds were both found to have levels of cyanobacteria exceeding the Department of Environmental Service’s accepted threshold of 70,000 cells per milliliter, according to a press release.
The current bloom is appearing as dark, green and brown water throughout the water, and recreationalists are advised to avoid contact with the ponds until the warning is rescinded, the release reads. Pets and small children should be kept out of any waters that have green turbid water, surface scums or blue-green or bright green flecks in the water column, according to the release.
Cyanobacteria appear in water bodies worldwide, but blooms and surface scums may form when excess phosphorus is present. The blooms can be highly toxic, and can cause both acute and chronic health effects that range in severity. Acute health effects include irritation of skin and mucous membranes, nausea, vomiting, and diarrhea. Chronic effects include liver and central nervous system damage.
In recent years, evidence has cropped up linking cyanobacteria toxins with ALS, often called Lou Gehrig’s Disease, an untreatable condition that slowly destroys nerve cells in the brain and spinal column. A cluster of ALS cases around Mascoma Lake in Hanover has drawn considerable attention and continued research.
James Haney, a researcher at the University of New Hampshire who has been studying cyanobacteria for decades, recently told the Monitor that an amino acid called BMAA found inside some species of cyanobacteria may be the cause. It has been linked to both ALS and Alzheimer’s disease, and is being used to create Alzheimer’s-like symptoms in chimpanzees so potential treatments can be tested.
But if BMAA is causing ALS in humans, Haney said, there’s a question: “How does it get from the lake to the people?”
Perhaps it is being ingested when people eat fish or swallow water, but it’s also possible that BMAA, a very small molecule, could be carried aloft as part of evaporation, where it could potentially be inhaled. UNH researchers are currently studying this possibility, Haney said, by testing to see how much BMAA exists in the very fine spray, or aerosols, produced by normal lake evaporation.
While summer is generally when cyanobacteria blooms occur, Haney recently said there are indications that more blooms are happening and that they’re lasting longer, possibly due to climate change.
The warning will be in effect until the cyanobacteria levels diminish, according to the DES.