Arsenic in soil and vegetation of contaminated areas in southern Tuscany (Italy)

Arsenic contents of soils and higher plants were surveyed in two former Sb-mining areas and in an old quarry once used for ochre extraction. Total As in the soils ranged from 5.3 to 2035.3 mg/kg, soluble and extractable As from 0.01 to 8.5 and from 0.04 to 35.8 mg/kg, respectively. The As concentrations in the different fractions of soil were correlated significantly or very significantly. Sixty-four plant species were analyzed. The highest As contents were found in roots and leaves of Mentha aquatica (540 and 216 mg/kg, respectively) and in roots of Phragmites australis (688 mg/kg). In general, the As contents of plants were low, especially in crops and in the most common wild species. In the analyzed species, roots usually showed the highest content followed by leaves and shoots. Arsenic levels in soils and plants were positively correlated, while the ability of the plants to accumulate the element (expressed by their Biological Accumulation Coefficients and Concentration Factors) was independent of the soil As content. Comparison with the literature data, relationships between the As contents in plants and soils, and biogeochemical and environmental aspects of these results are discussed.