Smith Point
The Hardy Ponder is an occasional dispatch highlighting a particular topic or concern about Hardy Pond and its surrounding wetlands.
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Cyanobacteria and HABs
Overview: what is it?
Cyanobacteria, often referred to as blue-green algae or CyanoHABs, can produce harmful toxins that pose serious health dangers to humans and pets. It is crucial to avoid contact with water that has visible algal blooms, as exposure can lead to symptoms ranging from skin irritation to severe illness. Children are at an increased risk, and death to a pet can occur within hours to days of exposure.
These blooms are promoted by warm temperatures, high nutrient levels (especially nitrogen and phosphorus), and slow-moving or stagnant water. These conditions often occur in summer and fall, leading to rapid algal growth.
The past two years have seen dangerous levels of CyanoHabs in Hardy Pond, starting in June and lasting well into the fall. Climate change has intensified these blooms, and until the root causes are addressed, it should be assumed that the water is contaminated during this time. The Hardy Pond Association, the Charles River Watershed Association, the City of Waltham and DEP continue to monitor and test during the season and hope in the future to implement remedial solutions.
What Does it Look Like?
Not all cyanobacteria blooms look the same. Cyanobacteria blooms on the surface of the water are generally green or blue-green and can look like spilled paint or fine grass clippings. Surface cyanobacteria blooms can also come in different colors, such as red or brown, which are not as common. It can be difficult to tell the difference between a cyanobacteria bloom and other blooms on the surface of the water. Some blooms can spread through the water, making it look like the water has changed color.
Additionally, benthic cyanobacteria grow on the bottom surfaces of water bodies and form dense mats of cyanobacterial material. These benthic mats range in color from black to brown to green. They can become detached from the bottom and accumulate along shorelines.
Other signs of a toxic bloom could include:
- earthy or musty odors
- dead waterfowl or other wildlife along the shoreline
It's impossible to tell if a cyanobacteria bloom or benthic mat contains toxins by looking at it, so as a precaution treat any cyanobacteria bloom as if it is toxic.
When in doubt, stay out!
Health Risks of Cyanobacteria
Exposure to cyanobacteria can lead to a range of health issues, which can vary in severity. For people, the following summarizes the potential symptoms based on exposure type:
| Exposure Type | Symptoms |
|---|---|
| Ingestion | ● Nausea, vomiting, diarrhea, headache, fever, dark urine, jaundice |
| Skin Contact | ● Rash, itching, blisters (allergic dermatitis) ● Conjunctivitis |
| Inhalation of water droplets | ● Respiratory irritation |
The type and severity of illness can depend on:
- The length of exposure
- the type and amount of cyanobacteria or toxins present
- how the person was exposed, for example through ingestion or skin contact
Prevention and Safety Measures
To minimize your risk of exposure to harmful cyanobacteria, take the following precautions:
- Avoid wading, swimming or drinking water from areas with visible algal blooms.
- Avoid boating and fishing.
- Check local health advisories before visiting water bodies.
- Rinse off any water that may have come into contact with skin or clothing after potential exposure.
If a waterbody is suspected of having a CyanoHAB, people and pets should avoid contact with and not consume the water, and fish caught in the affected waterbody should not be consumed.
NOTE: If you are concerned that you may have symptoms of exposure to a harmful algal bloom, please see your doctor. Telling your doctor about contact with water may help treat the illness properly. Contact your local health department if it is determined that your symptoms are the result of exposure.
Pet Exposure to CyanoHABs and what to do
Pets and other animals can be exposed to HAB toxins through drinking toxin-contaminated water, swimming in waters with a HAB, eating HAB mats, eating contaminated animals (e.g., fish or shellfish), or by licking toxins off their fur or hair.
But is it a HAB?:
- It's slimy or looks like foam, scum or mats on the surface of the water.
- The color is weird. Harmful algal blooms can be blue, bright green, brown or red and may look like paint floating on the water.
- It stinks. Some (but not all) harmful algae produce a nauseating smell.
If you suspect a HAB is present, don't let your pet drink, wade or swim in the water, or play in or eat scum mats. Also, DO NOT let your pet lick their fur after swimming in contaminated water.
Treat exposure! Death can occur within hours to days of exposure!
If you think your dog has gotten into a harmful algae bloom:
- Rinse them off immediately. Wear gloves to protect yourself and give your dog a thorough rinse in clean, fresh water.
- Watch for symptoms. Symptoms can arise anywhere from 15 minutes to several days after exposure. Take pets to the vet immediately if they suffer from:
- Diarrhea or vomiting; foaming at the mouth
- Weakness or staggering
- Tremors and seizures
- Loss of appetite; loss of energy
- Drooling, difficulty breathing or convulsions
- Any other unexplained sickness after being in contact with water
Watch an informative video from the CDC about Cyanobacteria
