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This book brings together research into the process of stream acidification and its impact on Welsh surface waters, carried out over the past decade or so. It is perhaps surprising that not until the 1980's was clear evidence of stream acidification assembled. In Wales, concerns over pollution had focused water quality sampling principally on the areas of traditional heavy industry and large urban popula tions served by inadequate sewerage systems and sewage disposal arrange ments. Mistakenly, it had been assumed that, with its prevailing westerly winds, Wales would receive precipitation substantially unpolluted by the industrial and urban emissions from Britain and mainland Europe. Assurance of the high quality of Welsh upland streams, the traditional nursery ground of salmonids, was eroded particularly by studies in the vicinity of Llyn Brianne reservoir in the catchment of the River Tywi of Central Wales. These demonstrated a clear correspondence between the biological quality and fisheries of streams in the catchment and aspects of stream chemistry, par ticularly pH, aluminium and calcium on the one hand, and catchment land use on the other. It is salutary to record that the first signals were of an inexplicable failure of the runs of migratory salmonids into the upper catchment, occupied by the Llyn Brianne reservoir and its influent streams, and the failure to restore the fishery by re-stocking with eggs and fry. Only then did the significance of the recent decline in some other upland lake and reservoir fisheries in Wales become apparent.
Inhaltsverzeichnis
1. Introduction to Welsh Studies.- 2. Chemical and ecological evidence on the acidification of Welsh lakes and rivers.- 3. Recent acidification of upland lakes in North Wales: palaeolimnological evidence.- 4. Atmospheric Deposition.- 5. The role of geology and soils in controlling surface water acidity in Wales.- 6A. Recent land use change.- 6B. Acidified Welsh lakes: the significance of land use and management.- 7. The role of acidity in the ecology of Welsh lakes and streams.- 8. Effects of acidification on fish and fisheries in Wales.- 9. Acid deposition - Drinking Water Quality and Health.- 10. Ecotoxicological studies of acidity in Welsh streams.- 11. Dissolved inorganic aluminium in acidic stream and soil waters in Wales.- 12. Determination of aluminium speciation in acid waters.- 13. Catchment characteristics and basin hydrology: their effects on streamwater acidity.- 14. Water quality changes from input to stream.- 15. The influence of land management on stream water chemistry.- 16. Hydrochemical modelling of acidification in Wales.- 17. Modelling the ecological impact of changing acidity in Welsh streams.- 18. Llyn Brianne - Acid deposition modelling.- 19. Amelioration of surface water acidity by catchment management.- Conversion table (equivalents and weights).- List of authors' addresses.
