The Use of Stable Sulfur, Oxygen and Hydrogen Isotope Ratios as Geochemical Tracers of Sulfates in the Podwiniówka Acid Drainage Area (South-Central Poland)

The paper presents the results of determinations of stable S and O isotopes of dissolved sulfates and O and H stable isotopes of waters from three ponds, that is, Marczakowe Doy acid pond, Marczakowe Doy fish pond and Podwiniówka acid pit pond, located in the Holy Cross Mountains (south-central Poland). The δ^sup 34^S^sub V-CDT^ and δ^sup 18^O^sub V-SMOW^ of SO^sub 4^ ^sup 2-^ in waters of three ponds (n = 14) varied from -16.2 to -9.5 [per thousand] (mean of -13.6 [per thousand]) and from -8.1 to -3.2 [per thousand] (mean of -4.8 [per thousand]), respectively. The mean δ^sup 34^S-SO^sub 4^ ^sup 2-^ values were closer to those of pyrite (mean of -25.4 [per thousand]) and efflorescent sulfate salts (mean of -25.6 [per thousand]), recorded previously in the Podwiniówka quarry, than to sulfates derived from other anthropogenic or soil and bedrock sources. The SO^sub 4^ ^sup 2-^ ions formed by bacterially induced pyrite oxidation combined with bacterial (dissimilatory) dissolved sulfate reduction, and presumably with subordinate mineralization of carbon-bonded sulfur compounds, especially in both Marczakowe Doy ponds. In addition, the comparison of δ^sup 18^O-SO^sub 4^ ^sup 2-^ and δ^sup 18^O-H2O values indicated that 75-100 % of sulfate oxygen was derived from water. Due to the largest size, the Podwiniówka acid pit pond revealed distinct seasonal variations in both δ^sup 18^O-H2O (-9.2 to -1.6) and δD-H2O (-29.7 to -71.3) values. The strong correlation coefficient (r ^sup 2^ = 0.99) was noted between δ^sup 18^O-H2O and δD-H2O values, which points to atmospheric precipitation as the only source of water. The sediments of both acid ponds display different mineral inventory: the Marczakowe Doy acid pond sediment consists of schwertmannite and goethite, whereas Podwiniówka acid pit pond sediment is composed of quartz, illite, chlorite and kaolinite with some admixture of jarosite reflecting a more acidic environment. Geochemical modeling of two acid ponds indicated that the saturation indices of schwertmannite and nanosized [straight epsilon]-Fe^sub 2^O3 (Fe^sup 3+^ oxide polymorph) were closest to thermodynamic equilibrium state with water, varying from -1.44 to 3.05 and from -3.42 to 6.04, respectively. This evidence matches well with the obtained mineralogical results.[PUBLICATION ABSTRACT]