What Happens If You Drink Water With Green Algae
Cyanobacteria, blue-green algae, occur naturally in fresh and saltwater bodies. There are many types of cyanobacteria, and some can produce harmful toxins called cyanotoxins.
Cyanobacteria can proliferate in freshwater lakes and rivers under favorable conditions, including:
- slow-moving streams
- high water temperature
- increased nutrients in the water, such as nitrogen and phosphorus
These conditions can sometimes lead to large blooms of cyanobacteria or blooms. When a bloom that contains toxin-producing cyanobacteria grows, these toxins can reach dangerous concentrations.
Seawater generally does not present problems with cyanobacterial proliferation.
Cyanobacteria and their Toxins Can Cause Harmful Health Effects
Exposure to a Bloom can cause:
- irritation to the skin, eyes, nose and throat
- stomach upset, diarrhea, or vomiting
- headache, muscle weakness, and fever
- Serious illnesses that can lead to death, such as:
- liver or kidney damage
- paralysis of the skeletal and respiratory muscles
The type and severity of the infection depends on:
- exposure duration
- the type and quantity of cyanobacteria or toxins present
- how the person was exposed, for example, by ingestion or skin contact
Children are at increased risk because they are more likely to swallow water accidentally and often spend more time in water than adults.
It is rare for people to die from exposure to cyanobacteria or their toxins. Only a few deaths have been reported worldwide.
There have been many more reports of animals dying after:
- drank water containing cyanotoxins
- licked or ate bloom substances from their fur or washed up on the shore
- These animals include livestock, wild animals, and pets, especially dogs. Animal deaths usually result from the rapid onset of respiratory failure.
Signs of Cyanobacterial Proliferation (water bloom)
Not all water flowers are the same. Cyanobacteria blooms on water surfaces are usually green or blue-green and may look like spilled paint or fine residue from grass clippings. Surface cyanobacteria blooms can also have different colors, such as red or brown, which are not as expected.
Differentiating between a cyanobacteria bloom and other surface blooms, such as green algae, can be challenging.
Some water blooms can spread through water, making it appear to be changing color.
Benthic cyanobacteria grow on the bottom of the water and form dense mats of cyanobacterial material. These benthic mats can be black, brown, or green. They can break away from the bottom and accumulate along the banks.
Other signs of toxic blooms include:
- Earthy or musty smell
- Dead waterfowl or other wildlife along the shoreline
By eye, it is impossible to tell whether a cyanobacteria bloom or a benthic mat contains toxins. As a precaution, treat any cyanobacterial proliferation as if it were toxic.
