§ Mr. KirkwoodTo ask the Secretary of State for the Environment if he will list each occasion in the last five years when domestic drinking water was contaminated to an extent which was assessed by his Department as constituting a threat to public health; and if he will make a statement. [9775]
§ Mr. ClappisonThere is a robust regulatory regime controlling drinking water quality administered by the drinking water inspectorate. Since 1990, there have been over 2,000 enforcement actions and some £2 billion of expenditure aimed at further improvements in drinking water quality. In 1995, the water companies in England and Wales carried out approximately 3.2 million tests on drinking water of which 99.5 per cent. showed that the relevant standards had been met.
611WWater companies in England and Wales are required to report all incidents in which drinking water quality might be affected. All incidents are investigated by the inspectorate. Most incidents are relatively minor happenings.
In those cases in which the drinking water was chemically contaminated and where the inspectorate has completed its investigations, there is no evidence that the magnitude or duration of the contamination was such as to endanger public health.
Most cases in which there is bacteriological contamination are trivial and often involve the notification of advice to boil water to a small number of consumers while tests are undertaken on the quality. In most cases, the advice is found to have been unnecessary, but consumers have been given protection rather than potentially left at risk.
The most significant risk to drinking water quality is the presence of cryptosporidium oocysts. On cryptosporidium, the notification to the inspectorate can relate to either the detection of cryptosporidium oocysts in treated water, or to an increase of the illness cryptosporidiosis in the community or both. The transmission of the illness occurs in a number of ways and often through contact with animals. One recent outbreak of cryptosporidiosis was found to be associated with a failure of a milk pasteurisation plant.
All incidents are investigated fully by the drinking water inspectorate. As cryptosporidiosis can be transmitted in many ways, the source of any outbreak has to be established through epidemiology. A case of South West Water Services Ltd. allegedly supplying water unfit for human consumption because of cryptosporidium is currently before the courts.
Notifications of events involving cryptosporidium are listed in the table under four headings. It should be noted that not all notifications become confirmed as incidents.
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Cryptosporidium oocysts detected in treated water but no reported increase of cryptosporidiosis Water company area Date Location Yorkshire Water 19 December 1991 Redmires Southern Water 19 March 1992 Broadfields Water Treatment Works (WTW) Severn Trent Water 20 August 1992 Fairholmes WTW Southern Water 8 September 1992 Steyning WTW Southern Water 22 October 1992 Testwood WTW South West Water 29 December 1992 Broomhill WTW Yorkshire Water 5 January 1995 Huby WTW Yorkshire Water 16 March 1995 Fixby WTW Essex and Suffolk 30 March 1995 Ormsby WTW Yorkshire Water 31 August 1995 Cottingham adit Yorkshire Water 13 September 1995 Kepwick Springs WTW (in raw water) South West Water 13 September 1995 Parracombe WTW Yorkshire Water 5 January 1996 Elvington WTW Yorkshire Water 10 January 1996 Elvington WTW Yorkshire Water 15 January 1996 Kepwick Springs WTW South West Water 29 May 1996 Littlehempston Cambridge Water 30 May 1996 Duxford/Linton South West Water 27 June 1996 Crown Hill WTW Mid Kent Water 3 July 1996 Burham WTW Southern Water
An increase in cryptosporidiosis in the community but oocysts not detected in treated water Water company area Date Location Southern Water 28 December 1990 Thanet area North West Water 5 May 1992 West Cumbria North West Water 27 March 1992 Barrow in Furness North West Water 14 December 1992 Warrington Northumbrian 15 June 1993 Sherbum North West April 1994 Chorley
Both oocysts detected in treated water and an increase of cryptosporidiosis in the community Water company area Date Location Yorkshire Water 13 November 1992 Bingley and Shipley South West Water 12 August 1995 Torbay/Littlehempston
Incidents still under investigation Water company area Date Location Wessex Water April 1993 Poole Yorkshire Water 11 June 1993 Gilstead North East 25 January 1996 Sunderland Yorkshire Water 21 March 1996 Tophill North West Water 29 April 1996 The Wirral Yorkshire Water 17 October 1996 Elvington WTW