Blue-Green Algae Blooms

August 13, 2019

With the warm weather we have been experiencing, the risk of blue-green algae blooms (cyanobacteria) in some ponds, lakes and rivers is increasing.  Here are some tips to keep you and your dog safe:

What is cyanobacteria?

Cyanobacteria or blue-green algae forms in freshwater when temperatures are warm, there is plenty of sunlight, and excess nutrients end up in the water (leaking septic systems, fertilizers, storm water runoff, as well as domesticated and wildlife waste) which then produces toxins that are extremely harmful to humans and pets.  Most blooms occur in Summer and early Fall.

How can I spot it?

Blue-green algae will look like a green scum on the water similar to pea soup or green paint.  It can infiltrate the water completely or rest on top of it in patches.  It also will have a bad odor.

What are the are health risks?

  • Ingestion of the toxin can cause gastrointestinal symptoms (vomiting/diarrhea/bloody diarrhea), liver damage, neurological damage or can be fatal (difficulty breathing, lethargy, drooling, seizures, shock, death).
  • The amount ingested is related to how many cells per milliliter of water, not the actual amount of water. So, if it is a very thick bloom and the dog does not drink the water directly – but stepped into the water and then licks the water and scum off his paws, this could be a toxic amount.
  • Another form of ingestion occurs on the shoreline itself. Pets have been known to eat the scum that washes up on shore.  When it dries out, it becomes crunchy and tempting for dogs to eat.
  • Inhalation can cause symptoms similar to asthma. This can even occur downwind of a body of water experiencing a bloom
  • Irritation to any exposed skin
  • Eye irritation if particulate becomes airborne (due to wind or spray)
  • Pets and small children are more susceptible due to their smaller body weights.

Safety Precautions:

  • Do not allow your pet to swim in any water that looks green or has a green scum floating in/on it
  • Do not allow your pet to drink any of the water or lick their paws if they have walked along the shoreline
  • Do not allow your pet to eat any of the algae along the shoreline
  • Symptoms can begin to manifest within one hour of exposure and prognosis is poor.
  • If there has been contact with blue-green algae, rinse pet off with clean water and immediately contact your veterinarian. (NEADS clients can contact NEADS). ASPCA Animal Poison Control Center 888-426-4435.

Known bodies of water with blooms as of 8/19:

  • Upper Mill Pond, Brewster, MA
  • Santuit Pond, Mashpee, MA
  • Bears Pond, Barnstable, MA
  • Charles River, Boston, MA
  • White Pond, Concord, MA
  • Cliff Pond, Nickerson State Park, Brewster, MA (on watch list)
  • Lovells Pond, Barnstable, MA (on watch list)
  • Scargo Lake, Dennis, MA (on watch list)
  • Jones Pond, New Durham, NH
  • Keyser Pond, Henniker, NH
  • Long Pond, Henniker, NH
  • Marsh Pond, New Durham, NH
  • Mirror Lake, Tuftonboro, NH
  • Hunkins Pond, Sanbornton, NH
  • Middle Danforth Pond, Freedom, NH