Geochemical baselines
The soil geochemical baseline map service of the Geological Survey of Finland (GTK) calculates regional baseline values using geochemical data stored in the map service database. In addition to GTK, soil geochemical data are provided by other national research institutes and some private companies.
Baseline values are needed as reference values in the assessment of soil contamination and remediation needs. Baseline concentrations refer to naturally occurring normal concentrations of hazardous substances in the soil (background) or elevated concentrations that are found in topsoil in a wide area in the surroundings of an area that is suspected to be contaminated (Government Decree on the Assessment of Soil Contamination and Remediation Needs (214/2007).
Several samples stored in the map service database have been taken from deep soil layers (subsoil) and they only represent naturally occurring element concentrations. In urban areas, in particular, samples are taken from the soil surface (topsoil).
The soil geochemical baseline can only be estimated for a single soil type at a time. The soil type or soil parent material is classified in the map service database as follows:
The map service provides baseline data on the following elements: antimony (Sb), arsenic (As), mercury (Hg), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), vanadium (V), thallium (Tl), boron (B), barium (Ba), molybdenum (Mo), selenium (Se), tin (Sn) and beryllium (Be). Baseline values for PAH and PCB compounds are available from some detailed study areas.
