Geochemical Baseline Survery of the Environment for the UK [G-BASE]

Natural abundances of chemical elements in stream sediments, stream water and soil samples systematically collected since 1968. 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.

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.

Analysed elements include 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 in stream sediments and soils and alkalinity, pH, conductivity, F and U and some for multi-element analyses including Al, Cl, Na, Si, SO4,NO4, and TOC for water.

Data products are available for partial Great Britain coverage, for the South-West, and for soils in UK urban areas.


Study area
Temporal extent
1968-01-01    to    …

Provenance & quality

The regional Geochemical Baseline Survey of the Environment (G-BASE) project has collected samples at a density of one sample per 2 km2; from mostly agricultural fields. Each sample site has a surface (5-20 cm) and a profile (35-50 cm) sample. Inorganic analytical data are available for over 50 determinands. High density soil geochemical data are also available for 25 major cities and towns of Great Britain. Soil samples were collected as part of the Geochemical Baseline Survey of the Environment (G-BASE) project at a density of four sites per 1 km2 within the build-up areas. At each sampling site a surface (5-20 cm) and a profile (35-50 cm) sample were collected (and a third topsoil sample from 0-2 cm across Greater London).
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 analysis is done on the 150 microns fraction of soil and stream sediment samples. The project now routinely determines the elements listed in the <2mm fraction of surface soils.


Spatial reference system
OSGB 1936 / British National Grid


National Soil Tabular