City of Oulu

Sampling year: 2016

Sample media: topsoil (0–10 cm): aqua regia extractable concentrations from the <2 mm grain-size fraction

Land use: various land use classes in the city centre

The Geological Survey of Finland (GTK) has investigated geochemical baseline concentrations in Savukoski – Pelkosenniemi region. Altogether, 31 topsoil samples were collected. Eight samples were located in Pelkosenniemi and 23 in Savukoski. Most of the samples represented glacial till (27 samples) and 4 samples were taken from sorted sediments. Concentrations for 42 elements were analysed after aqua regia extraction. In addition to that, Hg, carbon content and pH value were determined from all samples

Metal concentrations were usually low in natural till soil. The concentrations of arsenic, mercury, cobalt, chromium, copper, lead and vanadium in all soil samples were lower than the threshold values given in the Decree (VNa 214/2007).

The threshold values given in the Decree (VNa 214/2007) can be applied for all metals in Oulu, while the upper limit of baseline variation was lower than the threshold value for all elements. Upper limit of baseline variation was calculated for several elements that are not included in the Decree.

Report

Tarvainen, T. & Eklund, M. 2016. Oulun taajama-alueiden maaperän taustapitoisuudet. Geologian tutkimuskeskus. Arkistoraportti 83/2016. 76 s.http://tupa.gtk.fi/raportti/arkisto/83_2016.pdf

Upper recommended limits of baseline variation (SSTP) of selected elements in soils of City of Oulu and the threshold values (Decree 214/2007).