Blue-green algae – useful information
Some types of blue-green algae produce chemical compounds that can irritate the skin, as well as toxins that can affect the liver or the nervous system. About half of all the blue-green algal blooms examined have been found to be toxic. Their toxicity may depend on local conditions, as well as the species of algae concerned. Within the same bloom, some algae may be toxic, while others contain no such toxins. Even non-toxic blue-green algae may cause breathing difficulties and skin problems.
It is not possible to tell whether a bloom is toxic by its appearance, as this can only be determined in laboratory tests. This means that all intense algal blooms should be treated as potentially harmful.
- do not swim in water containing large quantities of blue-green algae
- keep children and pets away from the shore when there is blue-green algae in the water
- avoid swallowing water containing blue-green algae
- do not use water containing blue-green algae for washing, or in the sauna
- note that the toxins from blue-green algae do not disappear when water is boiled
- do not water vegetables such as lettuce with water containing blue-green algae
Blue-green algae may cause rashes or other symptoms affecting the skin. It can also sting the eyes, affect the nose and sinuses, and cause muscle pains or even nausea. If you are suffering from such symptoms, and suspect you may have swallowed or been swimming in water containing blue-green algae, follow these instructions:
- take a shower using a lot of clean water, taking particular care to rinse your eyes and skin
- if necessary take a carbon tablet (available from chemists); tablets may also be given to pets
- advice on poisoning is available round the clock from the Poison Information Centre – Tel. (09) 471 977
- in serious cases of poisoning contact a doctor as soon as possible
Taking algal samples for identification purposes
Samples of water containing algal blooms may be scooped up into a small, clean sealable glass or plastic container, which should be stored in a cool place, and sent to the authorities as soon as possible.
Samples can be sent for identification purposes by previous arrangement to the Finnish Environment Institute, or Centres for Economic Development, Transport and the Environment .
Samples should be sent together with an explanatory letter detailing the sampling time and location, the extent of the algal bloom, and the sender's address.
Microscopic tests can then be conducted to identify the species of algae, and clients can be informed whether the species concerned may be toxic.
Taking samples for toxicity tests
Toxicity tests are only conducted where algae has caused poisoning symtoms.
Samples for such tests should consist of at least half a litre of algae from the worst affected water, kept in a carefully cleaned glass or plastic container in a cool place.
Pack the sample carefully, together with ice packs to keep it cold if possible.
Send samples to the authorities as soon as possible, with detailed information on where and when the sample was taken, an estimate of the amount of algae present, and details of any symptoms suffered.
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