Information About Blue-green Algae and Water
What are blue-green algae?
Blue-green algae are tiny organisms which occur naturally in lochs, ponds, reservoirs, rivers and in the sea. They commonly occur during periods of prolonged hot weather but sometimes occur at other times of the year. Waters which have been polluted by agricultural, domestic or industrial discharges are prone to developing blue-green algae.
In still waters the algae can multiply to such an extent that they discolour the water which then appears green, blue-green, greenish brown or dark brown. Sometimes a scum may form on the surface. This scum can appear in different places at different times, but is most commonly found at the water's edge or shore line.
How do blue-green algae affect humans and animals?
Some, but not all the blue-green algae produce toxins or release these into the water. It is not possible to tell which algae do or do not produce toxins simply by their appearance. Laboratory analysis is needed for this. Therefore, it is advisable to regard all algal scums as toxic.
The toxins of blue-green algae can cause deaths of animals which come into contact with algae, either through drinking contaminated water or swallowing quantities of scum, or shoreline matter or crust. Dogs have died after going into the water at the shores of affected lochs.
Canoeists, wind surfers and swimmers who have either swum through algal scum or swallowed it have suffered from skin rashes, eye irritation, vomiting, diarrhoea and pains in muscles and joints. Illnesses can be severe, particularly where affected water has been swallowed.
Drinking water supplies are monitored to prevent any harmful effects on health from blue-green algae.
What should I do about blue-green algae?
Avoid all contact with the affected waters and ensure that children and pets are kept away. Farmers should ensure that their animals do not have access to contaminated water. This may require fencing around suspect waters.
If any member of the public finds areas of water affected with blue-green algae they should inform the local Environmental Health Service shown on the back of this leaflet. Environmental Health may then take action to ensure that notices are posted around the affected water to let local residents, visitors or patrons know what the position is. A typical warning notice which may be used is shown below.
What about eating fish from affected waters?
Blue-green algae and their toxins can adversely affect fish growth and health and, in some circumstances, can cause fish kills.
Fish should not be consumed if dead fish or strange fish behaviour is seen, blue-green algal scum is present or notices are displayed indicating the presence of blue-green algal cell numbers or toxins in unsafe levels.
Anglers and pet owners should not feed the liver or guts from fish to their pets, when fish are caught in waters effected by blue-green algae, as described above.
If you would like any further advice about blue-green algae, please contact Scottish Water or your local environmental health service. Depending on where you live this will be one of the following contact points:
Perth & Kinross Council
Mr T Brydone / Mr A Fleming
The Environment Service
Perth & Kinross Council
35 Kinnoull Street
PERTH PH1 5GD
Helpline Tel: 01738 476476
Email: TJBrydone@pkc.gov.uk / asfleming@pkc.gov.uk
Angus Council
Mrs L Simpson
Environmental & Consumer Protection Department
Angus Council
Dewar House
12 Hill Terrace
Arbroath DD11 1AH
Mr D Johnston
Environmental & Consumer Protection Department
Angus Council
County Buildings
Forfar DD8 3WE
ACCESSLine Tel: 08452 777778
Email: envhealth@angus.gov.uk
Dundee City Council
Miss I Coghill / Miss R Brooks
Dundee City Council
Environmental Health and Trading Standards Department
1 Highland Chief Way
Claverhouse West Industrial Park
DUNDEE DD4 9UA
Tel: 01382 436260
Scottish Water
Mr J Dalrymple
Scottish Water
Drinking Water Quality - Public Health Team
Old Bullion House
Invergowrie
DUNDEE DD2 5BB
Tel: 01382 563164
Email: john.dalrymple@scottishwater.co.uk
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