The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. Sampling Stream sediments were the primary sample medium for G-BASE. The sediment was collected from the centre of the stream and sieved through two sieves (2 mm and 150 µm) to obtain a fine grain-size fraction of <150 µm. Excess material from the <2 mm fraction was panned to collect a heavy mineral concentrate. Stream water samples were collected also at each drainage site. Four different water samples were collected routinely: two filtered waters (for major and trace elements) and two unfiltered waters (for pH, conductivity and alkalinity). The routine collection of soil samples was introduced in 1986 in areas of poor drainage density, and urban soil sampling commenced in 1991. Further details of the sampling methodology can be found in the G-BASE field procedures manual (https://nora.nerc.ac.uk/id/eprint/5190/). Sample analysis Stream water pH, conductivity and alkalinity were determined in the field. Water samples were returned to our laboratories and analysed by inductively coupled atomic emission and mass spectrometry (ICP-AES/MS), ion chromatography (IC) / ion selective electrode (ISE) for up to 50 chemical parameters. Waters were also analysed for non-purgeable organic carbon (NPOC) to determine dissolved organic carbon content. Most water samples were analysed for alkalinity, pH, conductivity, F and U and some for multi-element analyses including Al, Cl, Na, Si, SO4, NO4, and TOC. The <150 µm fraction of the stream sediment and the <2 mm fraction of topsoil were analysed by techniques including X-ray fluorescence (XRF) / direct reading optical emission spectrometry (DR-OES) to determine the concentration of up to 53 major and trace elements. Loss on ignition (LOI) and pH were determined in topsoil samples. Analytical data for the 150 micron fraction of soil and stream sediment samples are available for some or all of: Ag, As, B, Ba, Bi, Be, Ca, Ce, Cd, Co, Cr, Cs, Cu, Fe, Ga, K, La, Li, Mg, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Se, Sn, Sr, Th, Ti, U, V, Y, Zn, Zr. In later stages, the project also routinely determined the elements listed in the <2 mm fraction of surface soils. Sample storage and archive After preparation and analyses all soil, stream sediment and panned concentrate samples and excess material were stored and archived at the National Geoscience Data Centre (NGDC). The archive holds more than 40 years’ worth of material collected across the UK. Archived samples can be made available for further tests and analyses on request by contacting BGS Enquiries (mailto:enquiries@bgs.ac.uk).

The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. Deep soil samples (also known as profile soil samples) were taken from depths of between 35 cm and 50 cm at densities of 1 sample per two square kilometres (rural / regional areas) and 4 samples per square kilometre (urban areas). The G-BASE profile soils were generally sieved to 150 microns before analysis and determined by XRF for some or all of: Ag, As, Ba, Bi, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, I, K, La, Mg, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn and Zr. Since 2003, for both regional and urban sampling, deep soil samples and shallow soil samples were routinely collected from the same sites, but only the shallow soil samples were submitted for chemical analysis. The deep soil samples were archived in the National Geoscience Data Centre. For more information about accessing these samples and their analytical results, contact BGS Enquiries (enquries@bgs.ac.uk).

The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. Stream sediments were the primary sample medium for G-BASE, with an average density of one site per 1.5 km square. The drainage sampling sites cover most of Great Britain. Sediment was collected from the centre of the stream and sieved through two sieves (2 mm and 150 µm) to obtain a fine grain-size fraction of <150 microns. Analytical data (by a variety of analytical methods, including XRF and direct-reading optical emission spectrometry (DR-OES) for the <150 micron fraction of stream sediment samples are available for some or all of the following elements: Ag, As, Ba, Bi, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, I, K, La, Mg, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn and Zr. Some stream sediment samples were originally collected as part of the Mineral Reconnaissance Programme (MRP), and later re-analysed for G-BASE. These samples may have been assigned a new sample number, but will plot at the same site. For more information about accessing these samples and their analytical results, contact BGS Enquiries (enquries@bgs.ac.uk).

The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. The routine collection of regional soil samples was introduced in 1986 in areas of poor drainage density, with an average sample density of one site per 2 square kilometres. Urban soil sampling commenced in 1991, with an average density of four samples per square kilometres, for the urban areas of Belfast, Cardiff, Corby, Coventry, Derby, Doncaster, Glasgow, Hull, Ipswich, Leicester, Lincoln, Manchester, Mansfield, Northampton, Nottingham, Peterborough, Scunthorpe, Sheffield, Swansea, Stoke, Telford, Wolverhampton and York. Topsoil samples were collected between depths of 5 cm and 20 cm, and were sieved through a 2 mm mesh and milled to less than 150 microns. The data include XRF and direct-reading optical emission spectrometry (DR-OES) analyses for some or all of the following elements: Ag, As, Ba, Bi, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, I, K, La, Mg, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn and Zr. Loss on Ignition (LOI) and pH (in a slurry of 0.01 M CaCl2) were also routinely determined on 50% of regional and all urban samples. For more information about accessing these samples and their analytical results, contact BGS Enquiries (enquries@bgs.ac.uk).

The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. At G-BASE drainage sampling sites (average density: one site per 1.5 km square), sediment was collected from the centre of the stream and sieved through two sieves (2 mm and 150 microns). The fine-grained fraction formed the stream sediment sample and underwent chemical analysis. Excess material from the <2 mm fraction was panned using a wooden dulang pan to collect a heavy mineral concentrate. During the G-BASE project, these samples were archived, but not routinely submitted for chemical analysis. For more information about accessing these samples and their analytical results, contact BGS Enquiries (enquries@bgs.ac.uk).

The BGS Geochemical Baseline Survey of the Environment (G-BASE) was the national strategic geochemical mapping programme in Great Britain. The project set out to establish the chemistry of the surface environment by the collection and analysis of stream sediment, stream water and soil samples. Beginning in the late 1960s in northern Scotland and moving southwards across the country, the primary focus was mineral exploration, however, the project quickly developed to address important environmental concerns. The final G-BASE samples were collected in southern England in 2014. The outputs from the G-BASE project provide an invaluable, systematic baseline of geochemical information for Great Britain, serving as a marker of the state of the environment against which to measure future change. Stream water samples were collected at each drainage site. Four different water samples were collected routinely: two filtered waters (for major and trace elements) and two unfiltered waters (for pH, conductivity and alkalinity). Samples were collected for approximately 85% of Great Britain, but a wide range of analytes were only determined from the Wales and Humber-Trent atlas areas southwards. Stream water pH, conductivity and alkalinity were determined in the field. In the later stages of the programme, stream water samples from high order streams were analysed by ICP-AES/MS for 27 elements (Al, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S (as SO42-), Si, Sr, V, Y, Zn and Zr) and by quadrupole ICP-MS for 24 trace elements (Ag, Al, As, Ba, Be, Cd, Ce, Co, Cr, Cu, La, Li, Mo, Ni, Pb, Rb, Sb, Sn, Th, Tl, U, V, Y and Zr). Some samples were analysed by ion chromatography (IC). Automated colorimetric methods were used to determine Cl and NO3-, and an ion selective electrode (ISE) technique was used to determine F. Waters were also analysed for non-purgeable organic carbon (NPOC) to determine dissolved organic carbon content. All samples were routinely analysed for pH, conductivity and bicarbonate. Much of the UK coverage also includes uranium and fluoride analyses. For more information about accessing these samples and their analytical results, contact BGS Enquiries (enquries@bgs.ac.uk).

This Web service provides layers which show metadata relating to geochemical samples held by the British Geological Survey (BGS). The layers are point layers which indicate the spatial locations samples were taken from. Geochemical samples have been collected, analysed and stored in the BGS Geochemistry Database from different projects. The two most significant contributors to the database are the Geochemical Baseline Survey of the Environment (G-BASE) project and the Mineral Reconnaissance Programme (MRP). Each project took a variety of different sample types, including stream water, stream sediment, shallow soil and deep soil, and one layer is provided for each type of sample. The sample metadata provided include: sample name; sample type; the Regional Geochemical Atlas area (for G-BASE samples only) and a comma-separated list of available analytes. In many cases, samples are retained in the National Geoscience Data Centre (NGDC) at BGS Keyworth. For more information about obtaining samples or the results of their geochemical analyses, contact BGS Enquiries (enquiries@bgs.ac.uk).