Agricultural soils are often affected by multi-element contamination, yet the geochemical behavior of co-occurring metal(loid)s remains insufficiently understood. This study investigates the mineralogical associations and potential mobility of As, Sb, Cu, Pb, and Zn in 57 agricultural topsoils from seven Czech sites, including natural and anthropogenic geochemical anomalies. We combined chemical analyses of bulk and fine fractions with selective extractions and mineralogical characterization using X-ray diffraction and electron probe microanalysis. Arsenic concentrations reached up to 2000 mg/kg, while soils impacted by historical mining were enriched in Sb (≤ 540 mg/kg), Cu (≤ 1600 mg/kg), Pb (≤ 4460 mg/kg), and Zn (≤ 3630 mg/kg). These contaminants accumulated in the <10 μm fraction, posing increased health risk from wind transport and inhalation. Iron (oxyhydr)oxides in soil aggregates were dominant hosts of As, Cu, Pb, and Zn, with minor contribution from Mn (oxyhydr)oxides. In contrast, Sb was primarily associated with clay-rich aggregates, indicating stronger affinity for clays. Among discrete minerals, arsenates and (hydroxy)sulfates were the most common metal(loid)-bearing minerals. Ammonium sulfate extractions revealed a moderate potential mobility of As, Sb, Cu, and Zn (0.6–1.0%), while Pb was much less extractable (<0.05%). The patterns of potential mobility followed soil pH, increasing for As, Sb, and Cu at higher pH and for Zn and Pb at lower pH, reflecting their distinct adsorption behavior in soils. Our results highlight the key role of mineralogical associations in controlling the potential mobility of metal(loid)s in contaminated agricultural soils, with Sb showing notably different behavior from As.
Drahota et al. (Sun,) studied this question.