Current Research

Development of Methologies to Determine Bioaccessibility of Potentially Harmful Elements in Urban Soils

The re-use of brownfield sites is a key component in the current UK strategy to regenerate urban environments. Many UK cities have a long history of urbanisation resulting in elevated concentrations of potentially harmful elements (PHEs) such as As, Cd, Cr, Cu, Ni, Pb, V and Zn in the environment. Whether or not these substances constitute a hazard depends on a variety of factors including the extent to which they are taken up by living organisms (bioavailability/ bioaccessibility). One of the major pathways for PHE entry into the human body is through contact with contaminated soil. Soil ingestion can be inadvertent for example from vegetables or from hand to mouth contact, especially in children. The BGS has been developing laboratory-based methods to assess the bioaccessibility of PHEs in soils. The method, known as the Physiologically Based Extraction Test (PBET), attempts to mimic uptake conditions in the human gut. To date the method has only been validated for As and Pb.

The objective for this project is to carry out further assessments of soil quality in the urban area of Glasgow and to develop the PBET methodology to address the significant Cr contamination problems in Glasgow. The toxicity of metals depends fundamentally on their speciation and the work will build on the expertise in metal speciation at Edinburgh University. Samples will be characterised for their mineralogical composition (XRD and SEM) and for their oxidation state at Edinburgh University before undergoing PBET analysis at the BGS laboratories in Nottingham. This approach will allow the bioaccessibility data to be related to metal speciation and environmental controls to enhance our understanding of uptake. Site-specific exposure and risk assessment results of this type helps to inform whether or not remediation (a consideration of future regeneration) of 'contaminated' areas is necessary. The results of the project will therefore help to inform future regeneration in the Glasgow area and will contribute to cutting edge international development of human risk assessment techniques in relation to contaminated land.

Spectators' terrace constructed from chromium-ore reprocessing waste at Rutherglen Glencairn Junior football
ground.