§ Mr. Alex CarlileTo ask the Secretary of State for Wales what is the location of blue-green algae reported on four public supply reservoirs in Wales; what is the scientific description of such algae; and what assessment he has made of its potential effect if ingested by humans.
§ Mr. GristThe four public supply reservoirs where blue-green algae have been detected are:
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Reservoir Type of algae Dolwen, Clwyd Microcystis Plas Uchaf, Clwyd Anabaena, Microcystis Cefni, Anglesey, Gwynedd Anabaena Llandegfedd, Gwent Aphanizomenon, Anabaena Algae have also been found at four locations not used for public supply: Llyn Coron reservoir on Anglesey (anabaena detected), Henson hospital lake in Mid Glamorgan (anabaena, microcystis and aphanizomenon), Talley lake in Dyfed (gleostrichia and microcystis) and Eglwys Nunydd, West Glamorgan (aphanizomenon).
Blue-green algae (Myxophyta or Cynanophyta) are a large and diverse group of micro-organisms. Their basic structure and genetic organisation are bacterial in nature, but like green plants, they are able to produce carbohydrates by photosynthesis. The coloration is derived from the blue and green pigments used in photosynthesis. Unlike most plants, many blue-green algae do not need nitrogenous nutrients, having the ability to fix atmospheric nitrogen. Some, but by no means all, blue-green algae are toxic; several species which commonly occur in the aquatic environment can produce toxins.
Toxic algae can result in illnesses, including skin rashes, eye irritation, vomiting, diarrhoea, fever and pains in muscles and joints, in some recreational users of water who swallow or swim through the algal scums. There have been no reports of long-term effects or deaths in humans, but in some cases the illnesses were severe.
There is no evidence of illness resulting from drinking treated water supplied from the reservoirs affected by blue-green algae. In the four public supply reservoirs listed above where the algae have been detected, the algal scums have been limited to small areas on the water surface and have not adversely affected the water abstracted from deeper in the reservoirs for the purpose of water supply.
Furthermore, the normal processes of water treatment used are effective in removing algae from abstracted water or any organic compounds associated with the algal blooms.