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Bacteria warnings issued for bodies of water in several towns

New Hampshire Union Leader

August 17. 2018 10:26PM

Increased public awareness along with the July heat followed by the August rains may all be factors in a rising number of New Hampshire lakes and ponds with cyanobacteria warnings, according to state officials.

With families and tourists heading to the water for the weekend, the Department of Environmental Services (DES) issued five different warnings Friday in several pockets of the state for water bodies in Salem, Concord, Freedom, Barnstead and Hopkinton.

“We are not trying to close any water body or beach, but if you see these blooms stay away and please keep in touch with us because these can rapidly break up and even move from one shoreline to another,” said Amanda McQuaid, a DES spokesman.

“There have been so many reports that we couldn’t keep up with the testing, which was why we put them all out on Friday.”

Cyanobacteria are bacteria that grow in colonies to form surface water “blooms,” usually blue-green in color and consisting of thousands and even millions of individual cells, according to DES.

The bacteria occur naturally in most New Hampshire lakes, usually in relatively low numbers.

Cyanobacteria can increase as lake nutrients increase. And some cyanobacteria produce toxins that can adversely affect humans, domestic animals and livestock.

“We don’t have a lot of reports of people getting sick, dogs and even cattle are more likely to die or get sick because they drink the lake or pond water which humans typically do not,” McQuaid said.

These warnings are not based on a toxin evaluation and are intended as a precautionary measure for short-term exposure.

State officials advise lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions, typically where lake water has a surface scum, green streaks or blue-green flecks collecting along the shore.

Pet owners are encouraged to keep their pets out of any waters with a cyanobacteria bloom, McQuaid said.

This summer state analysts are finding several varieties of the bacteria and one of the most common of late is oscillatoria, which is usually found in deep water.

“Some of our folks think this could be as a result of all the rain moving the water quite a bit and bringing this scum to the surface that had been down deep,” McQuaid said.

The University of New Hampshire and Dartmouth College have been doing groundbreaking research into the health impacts of cyanobacteria exposures. One study that started in 2016 is looking at whether there was a link between high volumes of the environmental toxins and neurological diseases such as amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease.

UNH is also doing a separate study into whether there is a connection between cyanobacteria and loon mortality rates.

“There’s a lot of research but no firm conclusions as yet. There are a lot of different exposures you can have to cyanobacteria that might be worse than people swimming in it as it can get into food sources or become airborne,” McQuaid said.

Warnings issued on Friday include the following:

• Danforth Bay in Freedom: Oscillatoria bacteria was seen on Wednesday and tested Thursday in amounts found greater than 1 million cells.

• Hothole Pond in Loudon/Concord: A bloom of anabaena/dolichospermum bacteria that is green in color and found in plankton was tested Wednesday and had 194,000 cells.

• Halfmoon Lake in Barnstead: The oscillatoria bacteria tested Thursday had 1.45 million cells in it, state officials said.

• Elm Brook Park Beach in Hopkinton: An unidentified volume of cyanobacteria was observed this week and the warning was issued Friday. A similar warning for this beach went out in late June.

• Arlington Mill Reservoir in Salem: Testing on Thursday found samples ranging from a few thousand to millions of cyanobacteria identified as microcystis and woronichinia, which are liver toxins that are light blue in color. Residents are advised to look for and avoid accumulations of it at the town’s beach there.

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