Summer means blue-green algae blooms appear in lakes across New Hampshire.
Dr. Jennifer Graham, a limnologist with the U.S. Geological Survey, advises that if you are canoeing or kayaking and encounter a blue-green algae bloom, leave the area.
“The cyanobacteria do produce taste and odor compounds that can smell bad and so if you’re approaching an area and you can really smell an earthy or musty smell, and it’s prevalent, that’s also a good indicator that you may want to avoid the area that there may be an issue of cyanobacteria," Graham said in an interview.
She recommends notifying relevant state agencies about such sightings.
As a result of the budget freeze and the effort to maintain social distancing in the laboratory, the state isn’t monitoring water conditions at lake beaches, only ocean beaches, but still issues warnings when alerted to hazardous algae blooms.
The state has traditionally monitored water quality at beaches at lakes, great ponds, rivers as well as the ocean since 2003, relying on funding from the Beaches Environmental Assessment and Coastal Health (BEACH) Act, analyzing samples at both the state public health laboratory and the Limnology Center, both in Concord.
Testing looks at factors important to aquatic animal health such as turbidity and phosphorus, and also detects the presence of bacteria or other organisms that could be harmful to swimmers, most importantly cyanobacteria, whose growth is spurred by pollution, high temperatures and droppings from waterfowl.
Humans are at risk of exposure while recreating in affected waters through ingestion and skin contact. And when airborne, droplets containing the toxins can be inhaled while swimming. Humans are also exposed to cyanobacteria when eating fish from water bodies containing a high concentration of cyanotoxins.
Acute health effects include irritation of skin and mucous membranes, tingling numbness, nausea, vomiting, diarrhea and seizures. Chronic effects may include liver and central nervous system damage.
Dr. Amanda McQuaid of the state’s Harmful Algal and Cyanobacterial Bloom Program advises that people be cautious of lake water that has a surface scum and water that changes color or appears to have green streaks or blue-green flecks.
Lake Winona in Center Harbor and New Hampton is experiencing a cyanobacteria bloom, according to an advisory issued by the New Hampshire Department of Environmental Services, and warns swimmers and waders to steer clear and pet owners to keep their animals out of the water.
Lake users should avoid contact with the water because of potential toxins in areas experiencing the blue-green algae bloom that was first spotted on June 18, appearing as green clouds and flecks throughout the water and along the shoreline.
Water samples analyzed on June 19 reveal that concentrations of cyanobacteria were elevated in portions of Winona Lake.
In a press release, McQuaid said surface blooms can rapidly change and accumulate in various locations around a water body. She urged lakefront property owners to monitor their individual shorelines for changing conditions and to avoid water contact in areas experiencing a bloom.
The cyanobacteria advisory will remain in effect until the NHDES confirms that cell concentrations of the bloom have subsided.
According to NOAA, harmful algal blooms have been reported in every U.S. coastal state.
Nationwide, toxic cyanobacterial algal blooms have been implicated in human and animal illness and death in at least 43 states.
