The Helsinki Metropolitan Area

The Geological Survey of Finland (GTK) and the cities of Espoo, Helsinki and Vantaa have compiled data on soil geochemical baseline concentrations from the Helsinki Metropolitan Area. Arsenic concentrations are higher in the Helsinki Metropolitan Area than in most other parts of the country. Industry and traffic have increased the lead concentrations in topsoil in large parts of the Helsinki Metropolitan Area. Arsenic and lead are examples of elements for which soil baseline concentrations have to be taken into account in the assessment of soil contamination and remediation needs. The soil baseline concentration refers to both the natural geological background concentration and the diffuse anthropogenic input of elements. The report presents soil baseline concentrations in both natural and man-made soil parent materials in the Helsinki Metropolitan Area.

Publication:

Tarvainen, T., Hatakka, T., Salla, A., Jarva, J., Pitkäranta, P., Anttila, H. & Maidell-Münster, L. 2013. Pääkaupunkiseudun maaperän taustapitoisuudet. Summary: Geochemical Baselines in the Helsinki Metropolitan Area. Geologian tutkimuskeskus, Tutkimusraportti 201. http://tupa.gtk.fi/julkaisu/tutkimusraportti/tr_201.pdf

Statistics:

Man-made soil parent material

City of Helsinki

Sampling years: 1996–2009

Sample media: humus, topsoil (0–40 cm), aqua regia extractable concentrations from the <2 mm grain-size fraction

Sampling sites: Sampling sites represent natural areas, parks and residential yards. The Environment Centre of the City of Helsinki has studied soil geochemical baselines of the most common harmful elements since the late 1990s. In most cases, the samples have been taken from natural soils. Samples were taken from various soil parent materials (sand, till, clay, silt, peat, mineral soil rich in organic matter). Topsoil samples from minerogenic soils have been taken from the 0–40 cm mineral soil layer under the humus layer.

Aqua regia extractable concentrations of potentially harmful elements have been measured from all mineral soil samples. Concentrations of PAH and PCB compounds are available from some samples.

Publications:

Salla, A. 1999. Maaperän haitta-aineiden taustapitoisuudet Helsingissä. Eräiden alkuaineiden ja orgaanisten yhdisteryhmien luontaisten ja ilmaperäisten pitoisuuksien summat Helsingin maaperän pintakerroksissa. Helsingin kaupungin ympäristökeskuksen julkaisuja 15/99. 25 s + 7 liitettä. http://www.hel.fi/static/ymk/julkaisut/julkaisu-03-09.pdf

Salla, A. 2010. Maaperän haitta-aineiden taustapitoisuudet sekä pitoisuudet puistoissa ja kerrostalojen pihoilla. Östersundomin liitosalueen tuloksilla täydennetty versio. Helsingin kaupungin ympäristökeskuksen julkaisuja 6/2010. 16 s. http://www.hel.fi/static/ymk/julkaisut/julkaisu-06-10.pdf

Statistics:

Humus
Sand
Till
Mineral soil rich in organic matter

City of Espoo

Sampling year: 2009

Sample media: humus: concentrated nitric acid extraction from the <2 mm grain-size fraction; topsoil (0–25 cm and 0–2 cm) and subsoil: aqua regia extractable concentrations from the <2 mm grain-size fraction

Land use: 40 soil profiles from natural soil, 30 samples from urban soil

The Geological Survey of Finland (GTK) carried out geochemical mapping of urban soils (30 sampling sites; 0–2 cm topsoil and 0–25 cm topsoil) and natural soils (40 sampling sites; humus, topsoil 0–25 cm and subsoil) in Espoo and Kauniainen in 2009. Mineral soil samples were analysed using aqua regia extraction. Natural soils represented the most common minerogenic soil parent materials: clay, till and sand. Urban soil samples represented various land use types.

Arsenic concentrations were higher in all soil types in Espoo compared to most parts of Finland. The suggested upper limit value of baseline variation for arsenic was 10 mg/kg for urban soils. Concentrations of Co and V were often higher than the threshold values in natural clay soils. Concentrations of other potentially harmful elements were mostly lower than the threshold value. Concentrations of PAH and PCB compounds were clearly lower than the threshold values.

Urban soils showed higher concentrations of carbon, calcium, cadmium, copper, potassium, magnesium, manganese, nickel, phosphorus, lead, rubidium, strontium, uranium and zinc compared to natural topsoils.

Concentrations of most studied elements were similar in topsoil and subsoil samples. Topsoil was enriched with mercury, lead, cadmium, silver, molybdenum, antimony, selenium, tin and zinc.

Publications:

Tarvainen, T. 2009. Espoon maaperän taustapitoisuudet. Geologian tutkimuskeskus, arkistoraportti S41/2010/39. hhttp://tupa.gtk.fi/raportti/arkisto/s41_2010_39.pdf

Jarva, J. 2012. Espoon kaupungin pintamaan taustapitoisuudet. Geologian tutkimuskeskus, arkistoraportti 1/2012. http://tupa.gtk.fi/raportti/arkisto/1_2012.pdf

Statistics:

Urban topsoil

City of Vantaa

Sampling years: 1996, 1997, 2006

Sample media: humus and topsoil (0–25 cm): aqua regia extractable concentrations from the <2 mm grain-size fraction

Land use: forest soil and agricultural soil

The City of Vantaa has particularly studied the geochemical baseline concentrations of lead in topsoil, as the lead processing industry was important in Vantaa from the beginning of the 20th century to the late 1980s. Initially, studies were concentrated around lead processing industry facilities. Soil geochemical baselines were studied from 20 forest sample points in 1996 and 1997. More samples were taken from forest soils and agricultural soils in 2006. In addition to metal analysis, concentrations of PCB compounds were analysed from some samples.

Results are published in: