§ Mr. Hardyasked the Secretary of State for the Environment (1) if he will list those rivers and watercourses or areas of still water where the levels of mercury are such as to present a hazard to the public;
(2) which stretches of rivers and watercourses in England contain levels of mercury which are (a) above and (b) over twice the level of the limit set down by the European Economic Community.
§ Mr. John Patten[pursuant to his reply, 23 January 1986, c. 297]: The quality standard for mercury in fresh water required by EC directives 82/176/EEC and 84/156/EEC is an average annual concentration of 1 ug/1 total mercury. Apart from areas immediately downstream of discharge points, where the standard is not required to be complied with, it is known to be exceeded at only two places (in both cases by more than a factor of two).
- (a) In the Trent Mersey canal at Northwich. The quality standard is not met because of the very limited dilution available, although the discharge of mercury is well within the limit values for emissions laid down in the directive.
- (b) In the River Rother at Stavely. When new treatment plant is commissioned later this year it is anticipated that the quality standard will be met.
At neither of these sites, nor any other affected by major discharges of mercury, is water abstracted for public supply, or is there known to be any hazard to the public.