§ Mr. WrayTo ask the Secretary of State for Scotland what information on the pollution of drinking water in Scotland, including levels of aluminium and other toxic substances, his Department is gathering.
§ Lord James Douglas-HamiltonRecords are maintained of the quality classification of drinking water supply sources and of those supply zones where water does not currently meet the quality standards set in the EC drinking water directive and the Water Supply (Water Quality) (Scotland) Regulations 1990.
Where a standard is persistently infringed, a water authority may in certain circumstances apply for authorisation of a relaxation, but otherwise must submit an undertaking to make a necessary quality improvement within a specified time. There are separate arrangements for reporting specific pollution incidents or other significant water quality failures. No water supply zones have been notified as failing to meet the standards for any toxic substance. For lead arising from plumbing systems, water authorities are due to report by the end of this year on any zones where there is a risk that tap water will not meet the new lead standard, stricter than that of the EC directive, set in the water quality regulations.
The standard for aluminium, not classed as a toxic substance in the EC directive, may be relaxed if the aluminium is of natural origin. My answer to the hon. Member for Angus, East (Mr. Welsh) on 4 March 1991, column 65–66, gave details of maximum authorised levels of aluminium in such cases.
Other substances such as nitrates and pesticides are the subject of specific inquiries to water authorities from time to time.
Annual reports to be published by water authorities by 30 June 1991 will provide information and data on water quality standards in all supply zones.