HYDROCHEMICAL FACTORS AFFECTING THE NEUTRALIZATION DEMAND IN ACID SULPHATE WATERS
Many rivers and estuaries in Western Finland are subjected to highly acidic runoff from acid sulphate (AS) soils in their catchments. Acidic inflows, clearly exceeding the buffering capacity of the recipients, are common during most spring and autumn floods. AS soil acidity causes serious damage to the fisheries m common in the affected area. The present study surveyed the water chemistry of typical AS waters in order to reveal the variables best suited for AS water monitoring and mitigation planning. Extreme AS waters were characterized by pH values well below 4, high acidities, high metal concentrations and high sulphate concentrations. Titrable acidity proved to be the best variable in describing the overall AS water quality as well as the neutralization demand.