When is Blue Green Algae Toxic

Water Quality & Testing Guidance

Blue-green algae can produce toxins under certain conditions, but not all blue-green algae species produce toxins and not all blooms of toxic blue-green algae will produce harmful levels of toxins.

Toxin production is influenced by a range of environmental factors, including temperature, nutrient levels, and water chemistry.

Toxins are often produced by blue-green algae when the algae are under stress, such as during periods of high water temperature, low water flow, or high nutrient levels. Algae blooms can also occur in response to changes in the environment, such as increased nutrient inputs from human activities like agricultural runoff or sewage discharge.

It is also worth noting that some species of blue-green algae are more likely to produce toxins than others. For example, the genus Microcystis is known to produce microcystins, which are among the most common and potent toxins produced by blue-green algae.

In general, the best way to determine if a blue-green algae bloom is producing toxins is to have the water tested by a laboratory. If a bloom is suspected to be toxic, it is best to avoid contact with the water and to follow the advice of local health and environmental authorities.

What are microcystins?

Microcystins are a type of toxin produced by some species of blue-green algae (also known as cyanobacteria). They are among the most common and potent toxic substances produced by blue-green algae and can pose a significant risk to human and animal health if exposure is high enough.

Microcystins are hepatotoxins, meaning that they are toxic to the liver. They can cause a range of symptoms, including nausea, vomiting, abdominal pain, diarrhea, and liver damage. In severe cases, exposure to microcystins can lead to liver failure and death.

Exposure to microcystins can occur through drinking contaminated water, swimming in contaminated water, or eating contaminated fish or shellfish. The toxicity of microcystins can vary depending on the specific species of blue-green algae producing them, the concentration of the toxin in the water, and the duration and frequency of exposure.

If you are concerned about exposure to microcystins in a specific water body, it is best to check for signs or local information and guidelines published by the landowner or operator.

If you are a landowner or are responsible for a water body, and concerned over blue green algae levels, you may want to get it tested. We provide a blue green algae testing service.

In general, it is recommended to avoid swimming, boating, or engaging in other water activities in areas where blue-green algae blooms are present. If exposure to microcystins is suspected, seek medical attention immediately.

Which blue green algae species are toxic?

Many species of blue-green algae, also known as cyanobacteria, can produce toxins that can be harmful to humans, animals, and the environment. Some of the most toxic species of blue-green algae include:

Microcystis: This is a common type of blue-green algae that is known to produce several different types of toxins, including microcystins, which can cause liver damage, skin irritation, and other health problems in humans and animals.

Anabaena: This species of blue-green algae can produce the toxins anatoxin-a and cylindrospermopsin, which can cause respiratory distress, paralysis, and other serious health effects in humans and animals.

Aphanizomenon: This type of blue-green algae can produce a toxin called cylindrospermopsin, which can cause liver damage and other health problems in humans and animals.

Planktothrix: This species of blue-green algae can produce the toxin cylindrospermopsin, which can cause liver damage and other health problems in humans and animals.

It is important to keep in mind that not all blue-green algae species produce toxins, and that the presence of blue-green algae in water does not necessarily mean that the water is toxic.

However, it is best to avoid swimming, boating, or engaging in other water activities in areas where blue-green algae blooms are present, especially if the water has a green, thick, or scummy appearance.

If you do come into contact with water that may contain blue-green algae, it is important to rinse off with fresh water as soon as possible and to avoid ingesting the water.

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