The Link between Soil Geochemistry in South-West England and Human Exposure to Soil Arsenic

Abstract

The aim of this research is to use the whole soil geochemistry and selected bioaccessibility measurements, using the BioAcessibility Research Group of Europe (BARGE) method, on the same soils to identify the geochemical controls on arsenic (As) bioaccessibility and to gain an understanding of its spatial distribution in south-west England. The total element concentrations of 1154 soils were measured with As concentrations ranging from 4.7–1948 mg·kg−1, with the bioaccessible As of 50 selected soils ranging from 0.6–237 mg·kg−1. A Self Modelling Mixture Resolution approach was applied to the total soil element chemistry to identify the intrinsic soil constituents (ISCs). The ISCs were used as predictor variables and As bioaccessibility as the dependant variables in a regression model for the prediction of As bioaccessibility at all soil locations to examine its regional spatial distribution. This study has shown that bioaccessibility measurements can be directly linked to the geochemical properties of soils. In summary, it seems the primary source of bioaccessible As comes from soils developed directly over the mineralised areas surrounding the granite intrusions. Secondary sources of bioaccessible As are derived from As that has been mobilised from the primary mineralised source and then re-absorbed onto clay material, Fe oxides and carbonate coatings. This information can be of direct use for land development, since land contamination can affect the health of people living, working, visiting or otherwise present on a site.