HC Deb 29 June 1990 vol 175 c368W
Mr. Wallace

To ask the Secretary of State for Health what assessment he has made of the health implications to consumers of tap water from the presence of blue-green algae in water sources.

Mr. Dorrell

I am advised that, despite medical and scientific interest over at least 50 years, there is no convincing evidence that algal toxins in drinking water have ever caused illness in humans.

Several published reports from other countries refer to outbreaks of gastrointestinal illness and hepatitis occurring during a period of heavy algal growth in the source of the drinking water. In these incidents, the source water often smelt and tasted unpleasant and the water treatment was inadequate to remove the taste and odour which therefore remained in the drinking water. However, as noted in a review published in 1984 by the World Health Organisation, there is no evidence of the causal involvement of algal toxins in these episodes. There have been no such published reports from the United Kingdom.

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