Bio-availability of tungsten in the vicinity of an abandoned mine in the English Lake District and some potential health implications

This research addresses the occurrence, detection and possible fate of tungsten in the vicinity of an abandoned mine in the English Lake District. Aqua regia extraction and subsequent analysis of spoil and vegetation confirmed the presence of tungsten and other heavy metals. Spoil samples examined were last worked almost 100 years ago and the concentrations of copper, zinc, tungsten and arsenic detected demonstrate the environmental persistence of these metals in an area of relatively high rainfall. The bioaccumulation of tungsten by two species of plants is indicated and partitioning within different tissues of Calluna vulgaris is demonstrated. Mechanisms relating to mobility and speciation of the metals present were explored using sequential and single stage extraction systems. Tungsten appears to be relatively immobile when subjected to sequential extraction but increased bioavailability is indicated when single stage extraction using EDTA is employed.