Exposure to Toxic Elements
Historic mining activities have left a legacy of extensive areas of mine-related remains in southwest England , including spoil heaps with elevated levels of several toxic elements. Of particular concern is As, elevated concentrations of which have been reported in the region in soils, stream sediments, freshwaters, homes (housedusts and garden soils) and in human biomarkers such as hair and urine. It is generally accepted that exposure to elevated levels of inorganic As is associated with increased risk of cancer of the skin and other organs. Ingestion of dust and soil is an important exposure route for young children, a sub-group of the population which is known to ingest relatively large amounts of soil and dust. In the UK, a Soil Guideline Value (SGV) of 20 mg As per kg of soil has been set, based on risk assessment criteria and index doses. In southwest England, the risks of exposure to As are clear but a relatively small amount of data has been published on levels of As in the home environment in the region.
Our current research activities are updating and adding to this limited database via the collection and analysis of garden soils and household dusts from ex-mining villages in southwest England . We are also undertaking investigations into the bioaccessibility of As in collected garden soils and housedusts and deriving preliminary estimates of As doses for vulnerable receptors. Preliminary results have revealed dose estimates for young children of up to 3.53 µg kg -1 bw day -1 for housedusts and 2.43 µg kg -1 bw day -1 for garden soils, compared to the index dose, based on health risk assessments (and used for the derivation of the SGV) of 0.3 µg kg -1 bw day -1. The index dose was exceeded by 75% (18 out of 24) of the estimated As doses that were calculated for children aged 0-6 years. Our preliminary results raise concerns about As contamination of the home environment in southwest England and the potential implications for human health.
Publications
Rieuwerts, J.S., Searle, P. and Buck, R. (2006). Bioaccessible arsenic in the home environment in southwest England. The Science of the Total Environment 371, 89-98.