Isotopic analyses of spring and stream water sulfate from the Italian Alps and Apennines

Spring and stream water sulfates from mountainous, sparsely populated terrane in northern Italy display sulfur and oxygen isotope ratios scattered in the range 0 < δ18O < 12‰; − 7.5 < δ34S < 9‰. The δ34S values are heavier than expected from oxidation of typical sedimentary and igneous sulfides. Evaporites are absent from the bedrock of the drainage area; however, an evaporite-like pollutant may be present in the stream waters. No correlation is observed between δ18O of sulfate and of water, although experimental inorganic oxidation of sulfides indicate that oxygen should be contributed approximately equally by water and dissolved atmospheric oxygen.