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Update, October 13, 2022: The HABs in Prospect Park Lake are still "Widespread or Lakewide," according to the New York State Department of Environmental Conservation. The New York City Parks Department provided this photo.
Update, September 27, 2022: The description in this post of conditions in the lake still holds true. As of yesterday, the New York State Department of Environmental Conservation is continuing to describe the Harmful Algae Blooms in the lake as "Widespread or Lakewide." The New York City Parks Department provided the photo below.
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Update, July 21, 2022: A one-year pilot program for the two ecoWEIR systems in Prospect Park ended in December 2021. The natural filtration system combats Harmful Algal Blooms by removing their source of nutrition: nitrogen and phosphorus.
Brooklyn College Professor Jennifer Cherrier designed the system, and a $390,000 grant from the New York State Office of Parks, Recreation and Historic Preservation funded the pilot program. According to the Prospect Park Alliance, Brooklyn College is still working on the project and hasn't finished compiling the results of the pilot program.
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Toxins flourish every year in Prospect Park Lake from May through October. As the summer progresses, the toxins eventually become "widespread or lakewide," which is what their current status is.
The toxins are called "Harmful Algal Blooms" (HABs), and the specific ones in Prospect Park Lake are blue-green algae blooms or BGA (cyanobacteria).
They can make water look like pea soup. The water can also be blue, blue-green, green, yellow, white, brown, purple, or red. It can resemble spilled paint. Green streaks, dots, or globs might be on the surface of the water. Or, mats of blue or green pond scum might be floating on the water surface and accumulating along the shoreline.
When the blooms are large enough to be categorized as widespread, as they currently are, they can affect either the entire lake, a large portion of the lake, or most to all of the shoreline.
New York City's water supply feeds Prospect Park's Lake, waterfalls, and its other water features. Phosphates in the water make it safe for us to drink it, but they lead to excessive algae growth.
Every summer, New York City's Parks Department monitors the lake for blooms weekly and reports it to New York State's Department of Environmental Conservation (DEC). The DEC's map shows the location of the toxins throughout all of New York State. Some bodies of water with HABs might not have been reported to the DEC, so humans and animals should avoid contact with all floating mats, scum, and discolored water.
Adults, children, dogs, and other animals should not go into the lake or near the shoreline. Anyone who has been in contact with a HAB should rinse thoroughly with soap and water--or just with clean water, if that's all that's available at the moment.
Anyone who might have been exposed to a bloom and is experiencing any symptoms should get medical help immediately and should also contact the New York City Department of Health (DOH).
Possible effects of the toxins on living creatures are nausea, vomiting, diarrhea, skin or throat irritation, allergic reactions, and breathing difficulties. The toxins can also affect the liver and nervous systems if a lot of water is swallowed. Read more about this on the DEC website.
The DEC offers this advice and more:
- Swimmers should be concerned about HABs (Harmful Algal Blooms) in any lake in which they are considering swimming.
- Never drink untreated surface water, whether or not algae blooms are present.
- The New York Freshwater Fishing Guide advises anglers to avoid eating fish caught from areas that have the thick paint-like or pea soup-like coloration characteristic of cyanobacteria blooms.
- HABs cells can stick to animal fur and become concentrated when the animal cleans itself.
The Centers for Disease Control and Prevention says
- If your animal gets in water with a bloom, immediately wash it off with clean water. Do not let the animal lick cyanobacteria off of its fur.
- Call a veterinarian if your animal shows any of these symptoms of cyanobacteria poisoning: loss of energy, loss of appetite, vomiting, stumbling and falling, foaming at the mouth, diarrhea, convulsions, excessive drooling, tremors and seizures, or any unexplained sickness that occurs within a day or so after being in contact with water.