Blooms of blue-green algae at a major New Hampshire lake have prompted a warning; here’s how you can spot it yourself.
As we recently reported, authorities are issuing warnings to the public after finding elevated levels of algal blooms, more specifically that of blue-green algae or cyanobacteria. But what exactly is this substance, what makes it so dangerous, and how on Earth do you spot it?
New Hampshire officials issued a warning after detecting a threshold of 70,000 cells per milliliter for cyanobacteria in samples collected from Lake Monomonac on July 17. The largest of the blooms were found near the shore, and it was likely caused by an excess of phosphorus in the water.
Excessive exposure to cyanobacteria may result in only mild symptoms, like skin irritation. But it can lead to potentially more serious complications, like liver damage.
Blue-green algae produces neurotoxins, cytotoxins, hepatotoxins, and endotoxins. Exposure to high levels can even cause amyotrophic lateral sclerosis, or ALS. In fact, people who live within a half mile of such contaminated lakes have a 2.3 times greater risk of getting ALS.
How do you spot it? Blue-green algae looks just how it sounds, and often resembles a blue-green paint that has been spilled into the water. If you see a pea soup-like substance or foam that floats on the surface, that can be a telltale sign.
The statement from the New Hampshire Department of Health and Human Services follows below.
An elevated cyanobacteria cell concentration has been measured in Long Pond, Pelham, NH. Samples collected at the Pelham Town Beach on July 17, 2017 revealed that the state threshold of 70,000 cells/ml or greater of cyanobacteria was exceeded. The cyanobacteria were identified as Anabaena, Microcystis and Woronichinia. As a result, the New Hampshire Department of Environmental Services (NHDES) has issued a cyanobacteria warning for those who recreate on Long Pond. The current bloom is variable with some lake portions free of scum sightings, while other areas have accumulations of cyanobacteria along the shorelines or beaches. Samples collected on July 19 were clear; however the bloom had resurfaced on July 20 in high concentrations. Follow-up sampling on July 21 showed that the beach had cleared, but cyanobacteria are still concentrated in the lake. Please continue to monitor your individual shoreline for changing conditions as the bloom comes and goes quickly.
This warning is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. NHDES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions typically where lake water has a surface scum, clouds or blue-green flecks. NHDES also advises pet owners to keep their pets out of any waters that have a surface scum or blue-green or bright green flecks.
NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria warning has been issued, NHDES returns to affected waterbodies on a weekly basis until the cyanobacteria standards are again met. Cyanobacteria are natural components of water bodies worldwide, but blooms and surface scums may form when excess phosphorus is available to the water. Some cyanobacteria produce toxins that are stored within the cells but released upon cell death. Toxins 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.
The warning went into effect on July 20, 2017, and will remain in effect until additional samples reveal cyanobacteria levels have diminished.
Here’s more on cyanobacteria from the department’s site: What exactly are cyanobacteria? Cyanobacteria are photosynthetic, single-celled organisms lacking nuclear membranes, and many are capable of converting nitrogen to usable forms. Some species have resting cells that are dormant when conditions are unfavorable for cell reproduction. The cells remain dormant, normally in lake sediment, until optimum conditions exist to initiate cell reproduction. Cyanobacteria are present in virtually all natural environments including many extreme environments, such as hot springs and glacial ice.