This layer displays the urban areas for which there is an "urban geochemical mapping" report. An integral part of the G-BASE (Geochemical Baseline Survey of the Environment) mapping programme is to map and establish the soil geochemical baselines of urban areas. These data provide unique soil chemical information for the urban environment and are used to; assess the condition of soils within populated areas, identify and quantify human impact on soils in urban areas through comparison with the rural, natural soil geochemical background and Indicate elevated concentrations of potential harmful elements. 27 urban areas which have been sampled by the project to date.These include Glasgow, Nottingham, Ipswich and Cardiff.

This layer of the map based index (GeoIndex) shows the boundaries of the G-BASE (Geochemical Baseline Survey of the Environment) project mapping areas which are reported as geochemical atlases. The majority of atlases are for stream sediments, with data on stream waters and soils included when available. Separate stream sediment, soil and stream water atlases have been published for Wales. Wales and north of Humber-Trent are reported as hardcopy generally A3 sized publications. The Humber-Trent atlas is available as a pdf file on a CD-ROM. Atlases are available for Shetland, Orkney, South Orkney and Caithness, Sutherland, Hebrides, Great Glen, East Grampians, Argyll, Southern Scotland, Lake District, NE England, NW England and N Wales, Humber-Trent, Wales and West Midlands. Atlases are not available yet for the East Midlands, East Anglia, SE England and SW England.

The BGS has been commissioned by Defra to provide guidance on what are 'normal' levels of contaminant concentrations in English soils in support of the revision of the Part 2A Contaminated Land Statutory Guidance. The domain polygons and other data produced by this work are served as WMS here.

This layer of the map based index (GeoIndex) shows the locations where stream sediment samples are collected under the G-BASE (Geochemical Baseline Survey of the Environment) programme at an average density of approximately one site per 1.5 km square. Analytical data for the minus 150 micron fraction of stream sediment samples are available for some or all of the following elements by a variety of analytical methods (now predominantly XRFS): Mg, P, K, Ca, Ti, Mn, Fe, V, Cr, Co, Ba, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Pb, Bi, Th, U, Ag, Cd, Sn, Sb, Cs, La, Ce, Ge, Sc, Se, Br, Hf, Ta, W, Tl, Te and I. Stream sediment samples were also collected by the now defunct MRP programme and analytical data for the minus 150 micron fraction of samples is available for a variety of elements including Ag, As, Au, Ba, Bi, Ca, Ce, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Ti, U, V, W, Zn and Zr. Some of the MRP samples may have undergone several stages of analysis, some for inclusion in the G-BASE project. The samples may have been assigned a different sample number but will plot at the same site. Data is available for most Great Britain, apart from some parts of Southern England which have yet to be surveyed.

The map shows the location of excess sample materials from the G-BASE (Geochemical Baseline Survey Of The Environment) geochemistry project:- stream sediments, panned heavy mineral concentrates and soils are stored long term in the National Geoscience Data Centre and are available for use in other projects. The Minerals Programme (incorporating the Mineral Reconnaissance Programme) sample collection contains reference samples of drill cores, rocks, tills, soils, stream sediments and panned concentrates. These samples were collected in the period 1974 - to date in mineralised and potentially mineralised areas of the United Kingdom, principally in the northern and western Britain.

The G-BASE programme involves systematic sampling and the determination of chemical elements in samples of stream sediment, stream water and soil, to build up a picture of the surface chemistry of the UK. The average sample density for stream sediments and water is about one site per 1.5-2km square, and for soils one site per 2km square. Analytical precision is high with strict quality control to ensure countrywide consistency. Results have been standardised to ensure seamless joins between geochemical sampling campaigns. The data provide baseline information on the natural abundances of elements, against which anomalous values due to such factors as mineralisation and industrial contamination may be compared. Analytical data for the 150 microns 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, and Zr. Most water samples have been analysed for alkalinity, pH, conductivity, F and U and some for multi-element analyses including Al, Cl, Na, Si, SO4,NO4, and TOC. The project now routinely determines the elements listed in the <2mm fraction of surface soils.

This layer of the map based index (GeoIndex) shows the locations of panned drainage sediment samples. At most drainage sampling sites a panned heavy mineral concentrate is collected from the <2mm sediment fraction using a wooden dulang pan. For the Mineral Reconnaissance Programme these pans would be routinely analysed for mineral exploration purposes. The G-BASE project collects them at every drainage site but does not routinely submit them for chemical analyses and the samples are archived. Usually they are inspected when collected with a hand lens and the presence of mineralisation or contamination is recorded in the site information on field cards. The MRP has collected heavy mineral concentrates from some 33,000 drainage sites and analysed these for a variety of elements (predominantly by XRFS) including Ag, As, Au, Ba, Bi, Ca, Ce, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Ti, U, V, W, Zn and Zr.

This layer of the map based index (GeoIndex) shows the locations of over 12,500 rock samples from the land area of the United Kingdom gathered as part of the Mineral Reconnaissance Programme (MRP). The Mineral Reconnaissance Programme (MRP), funded by the DTI, carried out baseline mineral exploration in Great Britain between 1972 and 1997. The programme has been subsumed into the new BGS Minerals Programme, also funded by the DTI. The rock samples have been analysed for a variety of major and trace elements, mainly by XRF.

Water samples have predominantly been collected by the G-BASE (Geochemical Baseline Survey of the Environment) project at an average sampling density of one sample per 1.5 km square. Samples have been collected from approximately 85% of Great Britain but it is only from Wales and Humber-Trent southwards that a wide range of analytes have been determined. Currently G-BASE stream water samples collected from high order streams are determined by ICP-AES for 27 elements - Sr, Cd, Ba, Si, Mn, Fe, P, S (as SO42-), B, Mg, V, Na, Mo, Al, Be, Ca, Zn, Cu, Pb, Li, Zr, Co, Ni, Y, La, K and Cr; and by quadrupole ICP-MS for 24 trace elements - Li, Be, Al, V, Cr, Co, Ni, Cu, As, Rb, Y, Zr, Mo, Ag, Cd, Sn, Sb, Ba, La, Ce, Tl, Pb, Th and U. Automated colorimetric methods are used to determine Cl and NO3- and ion selective electrode is used to determine F. Waters are also analysed for non-purgeable organic carbon (NPOC) to determine dissolved organic carbon content. All samples have routinely been analysed for pH, conductivity and bicarbonate. Much of the UK coverage also includes uranium and fluoride analyses.

This layer shows data collected mainly by the Geochemical Baseline Survey of the Environment (G-BASE) programme. Geochemical data are available for soil samples for the Humber-Trent and East Anglia atlas areas (see the Geochemical atlas areas layer). Samples for East Midlands and part of Southeast England have been collected and are currently either undergoing analysis or data conditioning. More than twenty urban areas have also been sampled and top soil analyses are available for these urban areas (Belfast, Cardiff, Corby, Coventry, Derby, Doncaster, Glasgow, Hull, Ipswich, Leicester, Lincoln, Manchester, Mansfield, Northampton, Nottingham, Peterborough, Scunthorpe, Sheffield, Swansea, Stoke, Telford, Wolverhampton and York). Regional samples are collected at an average density of one site per 2 square kilometres, urban sampling is at a density of 4 samples per square kilometre. Top soil samples are collected at a depth of 5 - 20cm. It is sieved through a 2mm mesh and milled to less than 150 microns. The data include analyses for some or all of the following elements by XRFS: Mg, P, K, Ca, Ti, Mn, Fe, V, Cr, Co, Ba, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Pb, Bi, Th, U, Ag, Cd, Sn, Sb, Cs, La, Ce, Ge, Sc, Se, Br, Hf, Ta, W, Tl, Te and I. Loss on Ignition (LOI) and pH (in a slurry of 0.01 M CaCl2 ) is now routinely determined on 50% of regional and all urban samples.