| Summary: | This study about existence, causes and effects of oxidations in sulphide-bearing sediments in the coastland of northen Sweden is based upon an unique waterchemical sample program during 1990-2007 including the following parameters: pH, alkalinity, colournumber (mg Pt/l), COD (Chemical Oxygen Demand), sulphate, totalphosphorus, totalnitrogen and conductivity. For the years 2003-2007 the program was supplemented with metals. This investigation focus on the waterchemistry in surface water in lakes, watercourses and estuaries. The main objectives of this study is to give valuable contribution to the answers of the following research questions: What characterize the total waterchemistry in surface water where sulphide oxidations occur in the catchment areas?What conditions are responsible for and determine the large waterchemical variation in the watercourses? What conditions regulate the episodes of accidification?What period in summer show the most pronounced impact from sulphide oxidation on surface water chemistry?What chemical reactions and mechanisms are responsible for the changing waterquality connected with episodes of acidification?How large are the conribution from sulphide oxidation to acidity and high metal concentrations in watercourses relatively other potential sources?In what amounts are metals transported out in the estuaries in the Bothnian Bay from small coastal watercourses compared to big mountain rivers?Have the metals different distrubution patterns in the estuary?What is the environmental and ecotoxicological effects of suldphide oxidations in coastal areas of the Bothnian Bay nowadays and in the future?What consequences have the existence of sulphide oxidations for environmental monitoring and management and for the implementation of the EU Water Frame Work Directive?Results and conclusions from the investigations can be summarized:(1) An extreme waterchemical variation occur in the watercourses within and between years, The existence of sulphide oxidations in the catchment areas are ...
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