LEAD IN LONDON SOILS AND ITS RELATION TO DEPRIVATION INDICES

London Earth is a part of the Geochemical Baseline Survey of the Environment (G-BASE) Project, the British Geological Survey’s National Capability in geochemical mapping. In order to give insight into the environmental impacts of urbanisation and industrialisation – as well as characterise the geochemical baseline of the UK’s most populous city – over 6000 soil samples were collected at a density of 4 sites per km². The <2 mm fraction from the topsoil samples (5 – 20 cm) were milled, pelletised and analysed by X-ray fluorescence spectrometry (XRFS).

The Pb concentrations in the soiled ranged from 10.8 to >10000 mg kg^-1 with a median value of 185 mg kg^-1 and a mean value 301 mg kg^-1. The distribution of higher concentrations of Pb (measurements in excess of 346 mg kg‐1) in the Greater London Authority area is largely concentrated centrally in the oldest, most intensely urbanised and industrialised areas with little evidence of geological control.

Studies have shown that relatively low concentrations of lead in blood can lead to significant decrease in IQ of children (e.g. Jakubowski, 2011) leading to neuropathy and hypertension in adults. In addition studies also suggest that Pb exposure can be related to violent crime (Carpenter and Nevin, 2010).The ingestion bioaccessible fraction of Pb was measured using an in-vitro bioaccessibility test showing that 68% of the total Pb in London soils is bioaccessible. Measurement of Pb isotopic ratios in selected soils matched with those found in London air particulates and, to a lesser extent, with petrol lead. The effect of Pb in London soils on the quality of life has been assessed by statistical comparison with crime and deprivation indices. Initial studies suggest that there is not a direct link with crime but there is a clear relationship with deprivation indices relating to environmental factors. An overview of the relationships between Pb and deprivation will be presented.

References

CARPENTER, D O, and NEVIN, R. 2010. Environmental causes of violence. Physiology & Behavior, Vol. 99, 260-268.

JAKUBOWSKI, M. 2011. Low-level environmental lead exposure and intellectual impairment in children - the current concepts of risk assessment. International Journal of Occupational Medicine and Environmental Health, Vol. 24, 1-7.