Figure 1 schematic outline of the BARGE unified method
The UBM has now undergone initial inter-laboratory trials (Wragg et al., 2011) and been validated against an in-vivo model (Denys et al., 2012)and has become widely accepted as the method of choice in European Countries.
In a study of the financial impact of research carried out for the Natural Environment Research Council by the British Geological Survey (Natural Environment Research Council (NERC), 2009) examples of the use of bioaccessibility testing were given that showed that:
i) In one case the assessment enabled the re-use of existing site materials as part of the land remediation process, which subsequently led to reduced costs of approximately £3.75 million. In addition, approximately 3,750 lorry trips to landfill were avoided and 105 tonnes of CO2 equivalent were saved.
ii) In another example, BGS worked with Land Quality Management and University of Nottingham staff to save between £7-£30 million remediation expenses on one site. The more accurate bioaccessibility testing not only reassured local residents, but also allowed the stalled housing market in the area to restart.
Across England, there are an estimated 15,470 hectares of land in need of remediation. The cost of remediating this land is between £100,000-£325,000 per hectare, giving a potential market of £1.5-£5.0 billion. The research methods developed by BGS have the potential to save between £3.9 million and £12.6 million per year in remediating derelict land for development. Over a 20 year period, these cost savings are estimated to have a Net Present Value of between £55.0 million and £178.6 million.
The method is also being used on a national scale to provide bioaccessibility maps arsenic and Pb (Appleton et al., 2012a, b). Figure 2 shows an example of how a combination of the UBM test and data modelling has produced a map of the bioaccessible lead in soils in the Greater London area.
Figure 2 Estimated bioaccessible Pb in topsoils in the Greater London area (solid lines = motorways, major (A, B) and minor roads; Ordnance Survey Strategi data © Crown copyright 2012) (Appleton et al., 2012b)
Bioaccessibility testing cuts across a number of disciplines including chemistry, geochemistry, toxicology, human health and risk assessment but recent collaborative work untaken by research consortia such as the BARGE group have enabled the development of standardised testing protocols which have a direct impact on human health risk assessment and demonstrable economic benefits when used on a national and international scale.
Dr Mark Cave, British Geological Survey
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Appleton, J D, Cave, M R, and Wragg, J. 2012b. Modelling lead bioaccessibility in urban topsoils based on data from Glasgow, London, Northampton and Swansea, UK. Environmental Pollution, Vol. in Press.
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Wragg, J, Cave, M R, Basta, N, Brandon, E, Casteel, S, Denys, S e b, Gron, C, Oomen, A, Reimer, K, Tack, K, and Van de Wiele, T. 2011. An Inter-laboratory Trial of the Unified BARGE Bioaccessibility Method for Arsenic, Cadmium and Lead in Soil. Science of the Total Environment, Vol. 409, 4016-4030.