Knowledge is still lacking regarding the state of soil
The land is an integral part of our everyday environment. Soil and its diverse biota also provide us with vital products: food, raw materials, medicines, and clean groundwater. Soil ecosystems sequester carbon from the atmosphere and ensure that dead plant and animal remains decompose, returning organic matter back to the natural cycle.
Living and functioning soil is a non-renewable or slowly renewable natural resource. Soil can be permanently lost, for example through erosion. Even minor changes in soil reduce the diversity of the soil ecosystem and reduce its ability to maintain ecosystem services.
In addition to erosion, other identified threats to soil in Finland include soil compaction, humus depletion, and soil contamination by harmful substances. In residential areas, soil health is also threatened by the impervious covering of the soil. Adverse soil changes often occur slowly.
Carbon stocks in arable land have declined
The monitoring data shows that the amount of organic carbon – which essentially refers to the amount of humus – in Finland's arable lands has, on average, decreased. There is not enough long-term monitoring data for forest soils to draw the necessary conclusions yet. In any case, a lot of carbon has been lost during peatland drainages: humus has leached into water bodies and degraded as the soil surface layers have dried out and turned from anaerobic to aerobic.
Less heavy metals than before
The deposition of heavy metals and many other harmful substances has decreased in Finland, which has reduced the pressure on soil. Heavy metal depositions fell sharply, particularly in the 1990s, and for some substances the decline has continued even since then. An exception to this is mercury, whose deposition has remained more or less unchanged.
Many localised pollution incidents
Localised soil contamination has been caused by mines, industrial plants, wood impregnation plants, landfills, petrol stations and shooting ranges, among other things. Oil and chemical spills account for a large proportion of current pollution incidents. The extent and severity of pollution varies from case to case. In the most serious cases, the contaminants have degraded groundwater quality and compromised community water supplies. In Myllypuro, Helsinki, the soil of an old landfill site was so contaminated that the apartment blocks built on the site had to be demolished.
Acid sulphate soils pose a particular risk
Finland has plenty of so-called acid sulphate soils – more than any other European country. They are former seabeds that contain compounds of sulphur and iron, among other things. Sulfuric acid, aluminium and heavy metals can be released from these anaerobic layers if the groundwater level drops. In these areas, land drainage has acidified water bodies and increased heavy metal loads, as well as destroying or severely depleting fish stocks in many rivers.
Legislation prevents pollution
Soil pollution is prevented through legislation and municipal regulations. The Environmental Protection Act includes, among other things, a ban on soil pollution and regulations on waste management. The handling and storage of chemicals is regulated by laws and decrees on chemical and consumer safety. The legislation also requires the clean-up of contaminated soil. Drainage in acid sulphate soils is regulated by a notification procedure.
The EU's soil strategy includes a wide range of measures
The aim is to improve soil status across the European Union. The EU soil strategy 2030 includes several measures for promoting soil well-being, safeguarding soil biodiversity, and strengthening the role of soil in climate change mitigation. The strategy links soil as one of the solutions for global and local environmental issues.
Soil monitoring needs to be improved
The EU and Finland recognise the importance of improving soil monitoring. In Finland, information on the status, protection and sustainable use of soil is currently fragmented and based on monitoring programmes serving different needs. Comprehensive data collection is hampered by the mosaic-like variation of the soil conditions and land use characteristics of Finland, even within small areas.