Cyanobacteria and Cyanotoxins in sources of Norwegian drinking water
The Norwegian Scientific Committee for Food and Environment (VKM) will make a risk assessment of the various cyanobacteria and cyanotoxins found in Norwegian drinking water sources; and examine how these bacteria and toxins challenge the production of safe drinking water.
VKM is performing this assessment at the request of the Norwegian Food Safety Authority.
Cyanobacteria, also known as blue-green algae, constitute a diverse group of microorganisms that grow naturally in surface waters, which are often sources of drinking water. The prevalence of Cyanobacteria can be large, and can be seen as a film on water, called water blooms. Cyanobacteria can produce odorous compounds and/or toxins - cyanotoxins. Cyanotoxins can cause damage to the nervous system and to the human liver. Exposure to cyanotoxins can cause physical reactions, such as allergies. In some cases it can lead to death.
With climate change, increased rainfall is expected, which will in turn cause an increased supply of nutrient salts to drinking water sources. This can lead to increased growth of cyanobacteria.
Regulations for drinking water in Norway do not provide guidelines for sampling of cyanotoxins, and has no exposure limits set for cyanotoxins. The Norwegian Food Safety Authority requires more knowledge about cyanobacteria and cyanotoxins in drinking water.
The Norwegian Food Safety Authority has asked VKM for:
- an overview of the occurrence of various cyanobacteria and cyanotoxins in raw water sources and in drinking water in Norway.
- examples of suitable measures for limiting the occurrence of cyanobacteria and cyanotoxins in drinking water
- an overview of factors making it more likely for cyanobacteria and/or cyanotoxins to pose a challenge for the production of safe drinking water.
The Norwegian Food Safety Authority intends for the assessment to be used by drinking water treatment plants and by drinking water inspectors.
The Panel on Contaminants is responsible for the evaluation and approval of the final report drafted by the project group. The report is expected to be published in June 2021.