Geochemical baselines
Sampling years: 2006–2008
Sample media: humus: concentrated nitric acid extraction from the <2 mm grain-size fraction; topsoil (0–25 cm) and subsoil: aqua regia extractable concentrations from the <2 mm grain-size fraction
Soil parent materials: sand 78 profiles, till 95 profiles, clay 66 profiles
A soil geochemical baseline mapping project in the Tampere region (Pirkanmaa) took topsoil, subsoil and humus samples from 240 localities in the Tampere region during 2006–2008. The aim of the study was to provide the regional environmental authorities with information on the geological and diffuse anthropogenic baseline concentrations for different elements.
The concentrations of several elements are higher in Southern Tampere region compared to the rest of Finland. Concentrations of arsenic were elevated in all soil types. The highest arsenic concentrations were measured from sand and till samples from the Southern Pirkanmaa geochemical arsenic province (As province 4). Baseline values of arsenic concentrations were also higher than the threshold values given in the Decree on the Assessment of Soil Contamination and Remediation Needs (VNa 214/2007) in mineral soils of the Southern Finland arsenic province (As province 1) and in urban soils of the Tampere region. Arsenic concentrations can be higher than the threshold value in clay deposits even outside the delineated geochemical arsenic provinces.
In addition to arsenic, concentrations of many other trace elements are higher than the threshold values given in the Decree (214/2007). High natural concentrations of trace elements are a special feature of Southern Pirkanmaa. Naturally high arsenic, cobalt, chromium, nickel, lead, vanadium and zinc concentrations should be taken into account in land use planning.
Report:
Hatakka, Tarja (ed.); Tarvainen, Timo; Jarva, Jaana; Backman, Birgitta; Eklund, Mikael; Huhta, Pekka; Kärkkäinen, Niilo; Luoma, Samrit 2010. Pirkanmaan maaperän geokemialliset taustapitoisuudet [Electronic resource]. Summary: Geochemical baselines in the Pirkanmaa region. Geologian tutkimuskeskus. Tutkimusraportti 182. Espoo: Geologian tutkimuskeskus. 104 p. Electronic publication.http://tupa.gtk.fi/julkaisu/tutkimusraportti/tr_182.pdf
Statistics:
Concentrations of arsenic and several metals are higher in the southern part of the Tampere region compared to northern part. The above-mentioned report presents statistics including the upper limit of baseline variation values for various soil types and for different geochemical provinces. More information can be obtained using the 'Statistics' tool in the map service.
Sampling years: 2007–2009
Sample media: topsoil (0–25 cm): aqua regia extractable concentrations from the <2 mm grain-size fraction
Land use: 40 samples were taken from parks and residential yards, schools and day care centres.
The Geological Survey of Finland (GTK) coordinated a geological research project called TAATA in the Tampere district during 2007–2009 in co-operation with the cities of Tampere, Nokia, Orivesi and Ylöjärvi, the municipalities of Pirkkala, Lempäälä, Vesilahti and Kangasala, and with the Environmental Centre of Tampere region, the Council of Tampere Region, the Finnish Road Administration and Tampere Water. Urban geochemical mapping in the Tampere district was carried out during the TAATA project within all participating cities and municipalities.
Aqua regia extractable concentrations from the <2 mm grain-size fraction were analysed from mineral soil samples. Concentrations of PAH and PCB compounds are available for some samples.
Report:
Tarvainen, T. Jarva, J., Backman, B., Luoma S. ja Ruskeeniemi, T. 2009. Tampereen seudun taajamien taustapitoisuudet ja kohonneiden arseenipitoisuuksien vaikutus maankäyttöön. Geologian tutkimuskeskus, arkistoraportti S41/2009/31. http://tupa.gtk.fi/raportti/arkisto/s41_2009_31.pdf
Sampling years: 2012
Sample media: topsoil (0–10 cm): aqua regia extractable concentrations from the <2 mm grain-size fraction
Land use: 360 samples were taken from parks and residential yards, schools and day care centres.
The Geological Survey of Finland (GTK) has investigated geochemical baseline concentrations in the city of Tampere. Altogether, 360 topsoil samples (0–10 cm) were collected from urban areas in 2012. The sample sites represented various land uses in the city centre and other urban areas.
Arsenic concentrations in the urban soils were higher than the natural arsenic concentrations in other parts of Finland. An upper limit value of baseline variation of 26 mg/kg should be used in the assessment of soil contamination instead of the threshold value (5 mg/kg) in urban areas of Tampere. Arsenic in urban topsoil in Tampere is mostly natural in origin.
The baseline concentration of lead in topsoil is higher than the threshold value of 60 mg/kg given in the Decree (214/2007) in the centre of Tampere. The calculated upper limit of baseline variation for lead was 77 mg/kg for urban centre areas in the Tampere district. However, in most parts of the Tampere district, the Pb concentration in topsoil is lower than 60 mg/kg. The concentrations of zinc, cadmium and mercury are often higher in the topsoil of urban city centres compared to surrounding areas.
Concentrations of many trace elements are higher in clay deposits compared to other soil parent materials in the urban soils of Tampere. Concentrations of bismuth, cadmium, mercury, lead and sulphur are higher in humus in urban areas compared to natural soils. Coarse-grained man-made soil material had higher concentrations of Ti, Pb and S than other soil types. Concentrations of PAH and PCB compounds were low.
Report:
Tarvainen, T., Luoma, S. & Hatakka, T. 2013. Tampereen taajama-alueiden maaperän taustapitoisuudet. Geologian tutkimuskeskus, arkistoraportti 128/2013. 31 s. http://tupa.gtk.fi/raportti/arkisto/128_2013.pdf
Statistics:
Urban topsoil
Clay, silt
Coarse grained man-made soil material
Man-made soil material with a varying grain-size distribution
Mineral soil rich in organic matter