Acidification adjacent to an elemental sulfur stockpile: II. Trace element redistribution

Abstract

Total concentrations of Ag, As, B, Ba, Co, Cr, Cs, Ga, Hf, Hg, Mn, Mo, Ni, Rb, Sb, Sc, Se, Sr, Ta, Th, U, V, W, Zn, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, and Lu, were determined by instrumental neutron activation analysis (INAA) for samples of elemental sulfur and samples of soil material from selected depths adjacent to a large elemental sulfur stockpile. The objective was to determine the total content of trace elements and examine their redistribution within surficial till material influenced by extreme acidity resulting from the oxidation of elemental sulfur. The elemental sulfur did not contain detectable (by INAA) quantities of other elements to contribute to soil contamination. Elements mobilized within the acidified section were derived solely from the parent till. An Fe-rich indurated layer that formed at the interface of the acidified and calcareous layers acted as a scavenger for As, Co, and Ga. Formation of aqueous sulfate complexes probably inhibited attenuation of Mn, Sc, Th, U, Zn and rare earth elements. Barium and Hf were enriched in the acidified material while B, Rb, Cs, Sb, Sr, Ta, and V displayed no evidence of redistribution. Mercury displayed the unique behavior of volatilization to the atmosphere from the soil surface.Key words: anthropogenic acidification, trace elements, weathering