The British Geological Survey's Geochemical Baseline Survey of the Environment (G-BASE) project (Johnson et al., 2005) started to systematically collect soils as part of its UK regional geochemical mapping programme in the late 1980s.
Between 1986–1988, over the Chalk of the Yorkshire Wolds, where there was no or poor drainage yielding very few stream sediments, soil samples (standard depth 30–40 cm, i.e. deep soils) were collected from 502 sites at a density of one site per km2 (BGS, 1996).
Similarly, between 1988–1990 in some lowland areas of Lancashire, Cheshire and parts of north-east Wales, 2064 soil sites were sampled (standard depth 30–40 cm, i.e. deep soils) at a density of 1 site per 2 km2 in areas where the low-order drainage was sparse (BGS, 1997). Further soil samples collected from eastern parts of Wales are described in BGS (2000).
Since the 1990s soil samples have become part of the systematic geochemical mapping of the UK both in rural and urban areas at sampling densities of 1 site per 2 km2 and 4 sites per km2, respectively. A standard sampling methodology has been established and is described by Johnson (2005) and summarised below.
Topsoils (5–20 cm) and deep soils (35–50 cm) are routinely collected from every site though generally only the topsoils are analysed for some 50 elements by X-ray fluorescence spectrometry (XRFS). Some geochemical images of a selected number of elements are available in the electronic atlas of central and eastern England.
A summary map of the soil sample sites from England, Scotland and Wales — G-BASE soil sample sites map).
Northern Ireland was systematically sampled using G-BASE methodology (see Smyth, 2007) as part of the Tellus Project 2004–2007. As a result of the Tellus Project, Northern Ireland has the most comprehensive coverage of regional soil geochemical mapping of any nation of the UK and preparation of a geochemical atlas of the Tellus soil data (Northern Ireland) is in progress.
On-going rural sample continues in England around the perimeter of Greater London as part of the London Earth Project and in Scotland as part of the Clyde Basin Urban Super Project (CUSP). During the London Earth Project an additional sample of surface soil (0–2 cm) was collected from the majority of sites though this sample has not been routinely analysed.
From an environmental perspective, the geochemical mapping of urban areas using soils as a sampling medium has become a priority, as exemplified by the London Earth Project. The urban work is described by Fordyce et al. (2005) and more recently by Flight and Scheib (2011).
Urban geochemistry reports based on soil samples can be accessed from G-BASE urban geochemistry.
By the end of 2010 the following urban areas have been sampled: England — Corby, Coventry, Derby, Doncaster, Hull, Ipswich, Leicester, Lincoln, London, Manchester, Mansfield, Northampton, Nottingham, Peterborough, Scunthorpe, Sheffield, Stoke-on-Trent, Telford, Wolverhampton and York; Wales — Cardiff and Swansea; and Scotland - Glasgow. Belfast and Londonderry in Northern Ireland were sampled as part of the Tellus Project.
Soils are collected using a Dutch auger taking 5 subsamples at the corners and centre of a 20 m square. A topsoil (5 to 20 cm) and a deeper sample (35 to 50 cm) are taken at each site. Samples are collected from alternate 1 km grid squares though in urban areas sampling density is increased to four samples every km2. Samples are collected in KraftTM paper bags
The deeper soil samples are dried then sieved to -2 mm and are only routinely analysed in areas where drainage is absent. The topsoil samples are dried and sieved to 2 mm and pulverised in agate ball mills then pelletised for XRFS analyses of a wide range of trace and major elements (Ag, Al, As, Ba, Bi, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, I, K, La, Mg, Mn, Mo, Na, Nb, Nd, Ni, P, Pb, Rb, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn and Zr). Loss-on-ignition (450ºC) and pH is also routinely measured.
Geochemical data, including the G-BASE soil results are available under licence from the British Geological Survey. There is a data licencing and handling charge plus a charge of £0.50 per data record (with discount for large numbers).
Some or all of these charges can be waivered for academic use of the data. Contact BGS Enquiries.
The G-BASE data licencing policy is being revised in May 2011 to coincide with the release of the London Earth soil data. The London Earth data will be available free-of-charge but with a fixed data licencing and handling fee of £150.
Excess sample powders have already found use in many research projects. These are archived at the National Geoscience Data Centre (NGDC), British Geological Survey, Keyworth, Nottingham, UK. Information concerning the availability of the Tellus Northern Ireland geochemical data can be found on the Tellus data licensing web page.
BGS data are protected by NERC copyright, Tellus data are protected by Crown Copyright.
BGS. 1996. Regional geochemistry of north-east England. Keyworth, Nottingham. British Geological Survey. ISBN 0 85272 255 9.
BGS. 1997. Regional geochemistry of parts of north-west England and North Wales . Keyworth, Nottingham. British Geological Survey. ISBN 0 85272 307 5.
BGS. 2000. Regional geochemistry of Wales and part of west-central England: stream sediment and soil. Keyworth, Nottingham. British Geological Survey. ISBN 0 85272 378 4.
Flight, D M A, and Scheib, A J. 2011. Soil Geochemical Baselines in UK Urban centres: The G-BASE Project. Chapter 13, 186-206. In: Mapping the Chemical Environment of Urban Areas. Johnson C C, Demetriades, A, Locutura, J. and Ottesen, R T. (Eds.). John Wiley & Sons, Ltd., Chichester, UK.Fordyce, F M, Brown, S E, Ander, E L, Rawlins, B G, O'Donnell, K E, Lister, T R, Breward, N, and Johnson, C C. 2005. GSUE: urban geochemical mapping in Great Britain. Geochemistry: Exploration, Environment, Analysis, 5 (4), 325-336.
Johnson, C C. 2005. 2005 G-BASE field procedures manual. British Geological Survey, 65pp. (IR/05/097) (Unpublished).
Johnson, C C, Breward, N, Ander, E L, and Ault, L. 2005. G-BASE: Baseline geochemical mapping of Great Britain and Northern Ireland. Geochemistry: Exploration, Environment, Analysis, 5 (4), 347-357.
Smyth, D. 2007. Methods used in the Tellus Geochemical Mapping of Northern Ireland. British Geological Survey Open Report OR/07/022.