The British Geological Survey's Geochemical Baseline Survey of the Environment (G-BASE) project (Johnson et al., 2005) started to systematically collect stream waters as part of its UK regional geochemical mapping programme in the late 1960s (see History of G-BASE). Stream waters were initially collected just for pH, conductivity, F and U determination (i.e. from N Scotland). With improved analytical techniques stream waters became part of the suite of samples collected from each drainage sample site. These are collected from small streams (1st and 2nd order) and approximately 85% of Great Britain and Northern Ireland has been sampled. Only southern England remains unsampled (download map), plus areas of chalk and limestone (e.g. Yorkshire Wolds in NE England) were there are no surface streams to sample. The Tellus Project (Smyth, 2007) completed the national survey of stream water sampling begun in 1994 by the British Geological Survey (BGS) on behalf of the Department of Economic Development and Department of Environment (Flight et al., 1995).
Systematic sampling southwards across England ceased in 2007. On-going rural stream water sampling 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)".
Stream waters are collected at every G-BASE drainage site at a high average sampling density of 1 site every 1 - 2 km2 (see Johnson, 2005; Johnson et al., 2008). This high density of sampling enables the regional geochemical baseline to be interpreted at a local scale. As sampling is done in the summer months, occasionally during very dry periods, water could not be collected even though dry stream sediment could, hence there are some drainage sites with no waters.
The stream water results are generally presented in the series of geochemical atlases (see Geochemical maps and atlases) as interpolated geochemical images. A geochemical atlas dedicated to stream waters from Wales and parts of west-central England was published in 1999 (BGS, 1999). Central and eastern England stream water data for a selected number of elements is presented as an electronic geochemical atlas. A geochemical atlas of the Tellus water data (N Ireland) is in preparation.
|Filtered (0.45 µm cellulose filter) and unfiltered waters are collected from the same site as the drainage sediment. Samples are stored in NalgeneTM bottles and acidified as required by the analytical method. Filtered water samples are archived in the National Geoscience Data Centre post-analysis.||Alkalinity (by colorimetric titration), pH and conductivity determined on unfiltered samples, on location. Filtered samples analysed at BGS. ICP-MS: Li, Be, B, Na, Mg , Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Tb, Gd, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Tl, Pb, Th & U [56 elements]. Ion Chromatography: Br, Cl, F, NO2, NO3, SO4, PO4 [7 ions]. TIC/TOC analyser for Non-purgeable organic carbon (NPOC)|
Geochemical data, including that for G-BASE stream waters, 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.
Excess water samples collected since 2000 are archived in a cold store 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.
References and Links
BGS (1999). Regional geochemistry of Wales and part of west-central England: stream water. Keyworth, Nottingham. British Geological Survey. ISBN 0 85272 363 6.
Flight, D.M.A., Christie, J.L., Lister, T.R., Simpson, P.L. and Smith, B. 1995. Results of a pilot geochemical survey, Northern Ireland, Geological Survey of Northern Ireland Technical report No. GSNI/95/6., Geological Survey of Northern Ireland, Belfast. March 1995.
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.
Johnson, C.C., Flight, D.M.A., Ander, E.L., Lister, T.R., Breward, N., Fordyce, F.M. and Nice, S.E., 2008. The collection of drainage samples for environmental analyses from active stream channels. In: B. de Vivo, H.E. Belkin and A. Lima (Editors), Environmental Geochemistry: Site characterisation, data analysis and case histories. Elsevier, Oxford, pp. 59-92.
Smyth, D. 2007. Methods used in the Tellus Geochemical Mapping of Northern Ireland. British Geological Survey Open Report OR/07/022.