Algae and Cyanobacteria in Water

What are Algae?

Algae are a diverse group of organisms that contain chlorophyll and are often found in rivers and lakes.

What are Cyanobacteria?

Cyanobacteria are also found in rivers and lakes and also contain chlorophyll, but are classified as bacteria, unlike algae. Cyanobacteria are sometimes referred to as “blue-green algae”.

Significance in Water and Water Treatment

Certain species of Cyanobacteria can produce toxins, that can have serious health implications for animals, such as dogs and sheep. Humans can also be affected, with skin irritation the most common symptom.

Often, signs will be posted around lakes and reservoirs, warning people that Cyanobacteria are present in the water.

Poisoning due to ingestion of algal toxins is an extremely rare event in the UK. Studies in the UK have shown that conventional water treatment was effective at removing algae and their toxins. Also, extensive testing of drinking water throughout the country during the seasonal risk period demonstrated the absence of algae and their toxins. The main side effect of having Algae or Cyanobacteria in source waters, are taste and odour complaints from consumers, often described as earthy or musty in description. This is caused by metabolites released by the Algae or Cyanobacteria and have no health impact upon consumers.

Back to top