A method for the analysis of different species of antimony (Sb) that couples liquid chromatography with an inductively coupled plasma-optical emission spectrometry (LC-ICP-OES) system is presented. The method is simple and reliable to separate and quantify directly and simultaneously Sb(III) and Sb(V) in aqueous samples. The calibration curves showed high linearity at the three wavelengths tested. The limits of detection ranged from 24.9 to 32.3 μg/L for Sb(III) and from 36.2 to 46.0 μg/L for Sb(V), at the three wavelengths evaluated. The limit of detection for this method varied depending on the wavelength used. The lowest limit of quantification for Sb(V) (49.9 μg/L) and Sb(III) (80.7 μg/L) was obtained at a wavelength of 217.582 nm. The method sensitivity for Sb(V) was higher compared to Sb(III) at all the wavelengths considered. Samples containing different concentrations of Sb(III) and Sb(V) in three different matrices, i.e., water, basal culture medium, and anaerobic sludge plus basal medium, were analyzed. The coefficients of variation were low and ranged from 0.1 to 5.0 depending on the sample matrix. Recoveries of Sb(III) and Sb(V) were higher than 90% independently of the matrix analyzed and the wavelength used in the analysis.

Antimony (Sb) is a toxic and carcinogenic metalloid that can be present in contaminated water generated by mining operations and other industrial activities. Dissimilatory Sb(V) reduction to Sb(III) under anaerobic conditions by prokaryotic microbial communities has been reported; however, the fate of antimony in anaerobic wastewater treatment systems is poorly understood. This study investigated the potential of six different inoculum sources to reduce Sb(V) under anaerobic conditions and correlated the Sb(V) reduction rate with the microbial community composition. Microbial reduction of Sb(V) to Sb(III) by all the inoculum sources tested was observed in anaerobic incubations using hydrogen as an electron donor after a month. The highest reduction rate observed was 12.5 mg Sb per gram of volatile suspended solids per day. In some inocula, not only Sb reduction was observed, but also a decrease in the total Sb concentration, suggesting the precipitation of Sb(III). Metagenomic analysis revealed high variability in the community diversity associated with the origin of the inoculum. For the family taxonomic category, the three inocula that showed the highest Sb reduction potential were characterized by the presence of the Bacillaceae family.