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Information Letters

DWI Information Letter 26/2000 - 21 November 2000

To: Board Level Contacts of Water and Sewerage Companies and Water Companies in England and Wales

Dear Sir or Madam:

THE WATER SUPPLY (WATER QUALITY) (AMENDMENT) REGULATIONS 1999: CRYPTOSPORIDIUM IN WATER SUPPLIES: LABORATORY ANALYSIS

    Purpose

  1. The purpose of this letter is:

    1. to issue an update to the Standard Operating Protocol For The Monitoring of Cryptosporidium Oocysts in Treated Water Supplies to Satisfy the Water Supply (Water Quality) (Amendment) Regulations 1999 (the Protocol);

    2. to advise water companies of the requirements to validate new approved methods for analysis within laboratories; and

    3. to update the list of currently approved laboratories under the above Regulations.

    Part 2 of the Protocol

  2. Part 2 of the Protocol has been revised to clarify issues raised by the industry. The paragraphs which are changed are listed in Annex 1. A revised version of the Protocol is enclosed with this letter.

  3. Two new additional methods of analysis have now been approved. These are detailed in the enclosed copies of Part 2a and Part 2b of the Protocol.

    4. Within laboratory validation of new methods detailed in Part 2a or Part 2b of the Protocol

  4. Prior to the use of the new method outlined in either Part 2a or Part 2b of the Protocol, each laboratory must have validated the new method. This validation should be undertaken as described in the Protocol. This requires ten replicates, with no more than one replicate per batch of analysis and no more than two batches per day.

  5. Prior to the use of the new method outlined in either Part 2a or Part 2b of the Protocol, each analyst undertaking the revised part of the method must have validated the new method. This validation should be undertaken as described in the Protocol. This requires ten replicates, with no more than one replicate per batch of analysis and no more than two batches per day. Analyst validation data may be included in the laboratory validation data.

  6. The requirement for validation of each existing sampling site with the new method, as outlined in either Part 2a or Part 2b of the Protocol, does not need to be undertaken prior to the use of the new method. This validation comprising of ten replicates can be undertaken as part of the routine laboratory quality control procedures. The requirement for these ten replicates can be undertaken over the first 12 months of the use of the new method within the approved laboratory. Any new sampling site must still be validated prior to use of the method. Laboratory as well as analyst validation data may be included in the site validation data.

    7. Approved Laboratories

  7. A list of laboratories currently approved to undertake Cryptosporidium analysis under the Regulations is given at Annex 2. This list and future amendments will be placed on the Inspectorate's website.

    8. Enquiries

  8. Any enquiries about this letter should be sent to Malcolm Morgan, Zone 2/F3, telephone 020 7944 5987 or Tony Hallas Zone 2/F3, telephone 020 7944 5983 .

    9. Copies of this letter and the attachments are being sent to approved laboratories; the proficiency scheme laboratory, Pamela Taylor, Chief Executive, Water UK; Rodney Anderson, Water Supply and Regulation Division, Department of the Environment, Transport and the Regions; Bob Macey, Environment Division, The National Assembly for Wales; Tim Hooton, Water Services Unit, Scottish Executive; Randall Scott, Drinking Water Inspectorate for Northern Ireland; Rowena Tye, Office of Water Services; and David Harper, Department of Health.

  9. Please acknowledge receipt of this letter using the attached slip and reply paid envelope.

 

Yours faithfully

 

Michael Rouse
Chief Inspector
Drinking Water Inspectorate

Annex 1

List of paragraphs changed:

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Drinking Water Inspectorate,
Floor 2/A1, Ashdown House, 123 Victoria Street, London, SW1E 6DE
Telephone : 020 7944 5956 - Facsimile : 020 7944 5969
E-mail: dwi_enquiries@detr.gov.uk

Published 24 November 2000 Updated 11 July 2001
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