HEALTH ADVISORY: Jamaica Pond Closed Due to Suspected Algal Bloom

Based on initial visual inspection of the pond, it appears likely that Jamaica Pond is experiencing a harmful algae bloom. These blooms may produce toxins that can make people and pets sick. Park visitors are urged to avoid contact with the water and any areas of algae concentration, even on shore. 

Jamaica Pond is temporarily closed to water activities.

During the closure, park visitors cannot:

• Swim, fish, boat or engage in other recreational activities on or in the water
• Allow dogs to swim in or drink the water 

If you, your child, or your dog comes in contact with the water or an algae bloom, rinse off immediately. 

Blue-green algae can form harmful blooms in lakes, ponds, and rivers that make the water murky, and can sometimes make the water look like pea soup or paint. The current suspected bloom in Jamaica Pond appears like a dull green discoloration that could be confused as otherwise safe pond water. Blue-green algae blooms can produce toxins that may make people and pets sick. Toxins may be present within the algae cells or in the water. 

For humans, the primary concern is ingestion of water containing blue-green algae while swimming.  Direct skin contact with the blue-green algae and inhalation of water droplets containing blue-green algae or toxins is a secondary concern. For dogs, the primary concern is the ingestion of water containing blue-green algae or scum that has washed ashore or gotten onto their skin or fur. 

Contact may cause skin and eye irritation, and inhalation can cause respiratory irritation and exacerbate pre-existing respiratory conditions. Toxins are not absorbed through the skin. Ingestion of blue-green algae can cause acute gastrointestinal symptoms, such as vomiting and diarrhea. If the blue-green algae are producing toxin(s), the health effects can be more serious, especially for small pets due to their smaller body weights. Ingestion of the toxins can cause acute gastrointestinal distress and, depending on the specific toxin, can affect the functioning of the liver, kidneys, and/or neurological systems and in severe cases can result in death. 

Call your veterinarian immediately if your dog has been around an algae bloom and shows symptoms such as vomiting, staggering, drooling, or convulsions. These symptoms present themselves soon after exposure. Dogs have been known to eat the scum that washes ashore and/or lick scum out of their fur. In Massachusetts and in many other states, canine deaths have been documented due to the ingestion of harmful algae. 

When will this advisory be lifted?

Algae blooms may last for weeks in the summer or may disappear quite quickly. The Boston Public Health Commission (BPHC) will coordinate with the Massachusetts Department of Public Health (DPH) over the coming weeks. DPH water sampling will determine when the advisory can be lifted. DPH recommends that the recreational water advisory not be lifted until two consecutive weekly samples show algal cell counts below the safe limit of 70,000 cells/milliliter of water.  If you have any questions, concerns, or would like more information, please call the Mayor's Health Line at 617-534-5050.