Bioavailability of tungsten and associated metals in calcareous soils in the vicinity of an ancient metalliferous mine in the Corbières area, southwestern France.
The mobility and bioavailability of tungsten and associated metals are examined in calcareous soils and subsequent bioaccumulation by four species of plants is determined. Apparent bioavailability of metalliferous cations indicated by accepted monitoring methods and actual bioaccumulation is compared using regression analysis. Two soil extraction procedures were used without significant correlation between the methods at all stages, with the exception of copper and arsenic. More importantly, perhaps, the bioaccumulation by various tissues of Buxus sempervirens did not significantly correlate for the majority of target metals for each extraction procedure. Possible accumulation of toxic cations by a dying tree species was also examined. The availability of tungsten and associated metals in calcareous soils was compared with previous investigations on acidic soils, resulting in confirmation that tungsten in particular, in naturally occurring ores, is more readily mobilized under alkaline conditions.