Sources of natural and anthropogenic sulphur around the Teruel power station, NE Spain. Inferences from sulphur isotope geochemistry

Stable sulphur isotopic ratios were used for the identification of sources of atmospheric sulphur compounds, and the assessment of their contribution to the atmospheric sulphur deposition load around a coal-fired power plant in NE Spain. The study consists of a number of stages: identification of th e sources, clarification of the chemical pathways of the sulphur from these sources, assessment of their contribution to the overall load,and determin ation of the emission impact on the natural sulphur cycle in the area. Sulp hur isotope analyses were carried out on bedrock and sediment samples, surf ace and groundwater, wet-only and total deposition, total suspended particl es and SO2 emissions from the power plant. The results are useful in indica ting the sources of sulphate in the atmosphere, allow us to exclude some ot her potential sources, and demonstrate that: (a) the total load of sulphate is largely unaccounted for by Cl and is, therefore, of non-sea spray origi n; (b) this excess sulphate does not originate from bedrock and sediments i n the area; (c) there is a significant contribution of sulphur from remote sources such as the Atlantic-north European areas; (d) the multitude of loc al and remote sources involved and the rapid change in their relative contr ibution do not facilitate the quantification of the deposition derived from the emissions of the power station. However, given the low conversion effi ciency and the relative constancy of the delta(34)S Of the emitted SO2 it i s suggested that sulphate deposits with delta(34)S Of around 2.5 parts per thousand originate from the Teruel power station. (C) 1999 Elsevier Science Ltd, All rights reserved.