Does antimony affect microbial respiration in Mediterranean soils? A microcosm experiment

Abstract

The aim of this study was to determine the effects of antimony on soil microbial respiration. Two Mediter-ranean calcareous soils were sampled: a contaminated soil close to an abandoned lead and silver smelter and a soil far from the pollution source and considered not to be contaminated. Two forms of anti-mony, antimony trioxide (Sb 2 O 3) and potassium antimonyl tartrate trihydrate (C 8 H 4 K 2 O 12 Sb 12 ·3H 2 O), were tested at three concentrations (50, 500 and 5000 ppm) in controlled conditions under short-(3 days) and medium-(3 months) term incubation. Modifications in the substrate-induced respiration (SIR) were assessed by gas chromatography respirometric measurements. Results clearly showed that SIR was immediately and significantly more affected by Sb input in a non-contaminated soil than in a long-term contaminated soil, especially since the concentration was high and Sb was added to a more soluble and available form (tartrate instead of mineral oxide). Antimony (Sb), a metalloid of the same periodic group as arsenic (As), is known to present toxicological properties, but its effect on the environment and on human health is little documented. Worldwide production of Sb is considerably greater than of As, Sb having a wide range of uses (manufacture of semiconductors, diodes, flame-proof retardants, lead hardener, etc.) (Filella et al. 2002). As a consequence of its extensive use, many soils have been contaminated by this metalloid worldwide, through geogenic sources or anthropogenic pollution from activities such as mining, smelting, industry and agriculture (Douay et al. 2008).