§ Mr. Heseltine
As my hon. Friend the Under Secretary of State made clear in the reply he gave to the hon. Member on 20 June 1979, water quality management in the Mersey Estuary is a matter for the North-West water authority. The hon. Member has shown a particular concern, however, in the recent deaths of some 2,500 birds in the middle estuary. I understand that the birds died of acute lead poisoning resulting from the presence of trialkyl lead in their feeding grounds. This compound is derived from tetraethyl lead which is used by several manufacturing industries on the banks of the estuary. Despite intensive investigations by the water authority, aided by local industry and wildlife organisations, it has not proved possible to identify the 613W source of this particular discharge. While the indicident now appears to be ended, work is still proceeding on a study of the toxic effects of this material in order to determine the action necessary to guard against a recurrence of such pollution.