§ Mr. Wilsonasked the Secretary of State for Scotland (1) if he will give figures to show the current levels of deposited acidity in grams of hydrogen ion per square metre per year, deposited non-marine sulphate, and deposited nitrate in grams of sulphur and nitrogen per square metre per year for (a) the Loch Ard area and (b) the Merrick in Galloway; and what is the number of years over which the figures are averaged;
(2) if he will publish estimates of levels of deposited acidity in grams of hydrogen ion per square metre per year and deposited non-marine sulphate and deposited nitrate in grams of sulphur and nitrogen per square metre per year for (a) the Loch Ard area, central Scotland and (b) the Merrick in Galloway for the years 1990, 1993, 1996, 1999 and 2001, respectively.
§ Mr. AncramFigures of the levels of deposited acidity in the Loch Ard area and the Merrick are not available but values can be deduced from the date published by the Department of the Environment review group on acid rain in 1983 and available from Her Majesty Stationery Office. Ranges representative of these general areas, averaged over three years 1978–1980, within which depositions may be expected to lie are set out in the table. factors. Data from a number of Scottish sites suggest, however, that if present emission patterns remain relatively constant there is unlikely to be a significant change in deposition levels over the Loch Ard and Merrick 549W areas in the next 15 years. A reduction in emissions would, however, be expected to result in generally reduced depositions.
§ Mr. Wilsonasked the Secretary of State for Scotland what information he has to the maximum level of sulphur deposition, expressed in kilograms per hectare per year, which lochs and freshwaters in acid-sensitive areas of Scotland can tolerate without experiencing long-term acidification; and what information he has as to which specific bodies of water have already been acidified beyond this maximum level.
§ Mr. AncramThe sensitivity of lochs and freshwaters to acidity varies according to geological and other conditions, and the level of sulphur deposition above which ecosystems may become affected is subject to continuing research. The biological effects of long-term acidification have, however, been evident so far only in the surface waters of the Galloway and Trossach areas.
§ Mr. Wilsonasked the Secretary of State for Scotland what percentage change there has been in the concentration of acidity of rainfall in Scotland between 1979 and 1984.
§ Mr. AncramCurrent research indicates that between 1979 and 1984 the concentration of acidity in rainfall in Scotland has reduced substantially, probably by 40 to 50 per cent., although the trend has not been consistent over the country due to effects of variable weather patterns. These figures are based on measurements taken since 1978 at a number of different sites throughout the country.