Sulphur and Oxygen Isotopes in Sulphate

The origin and the fate of sulphate in groundwater has concerned hydrogeologists for many decades. With increasing industrialisation throughout this century, the differentiation between natural and ‘man-made’sulphate became important. A particular challenge is evaluating potential and existing additions of the latter to groundwater and drinking water supplies. On regional and even global scales, sulphate as a component of ‘acid rain’captured scientific and public awareness in the 1970s and 1980s. Subsequently, intensive research programs on the effects of atmospheric sulphate deposition on terrestrial and aquatic ecosystems were initiated. Today, more than two-thirds of the sulphate in atmospheric deposition in heavily industrialised regions of the northern hemisphere is of anthropogenic origin (Section 7.3.2.4). The rate and the degree to which these increased sulphate inputs have led to acidification of surface water and groundwater has been a matter of considerable scientific debate in the past two decades.