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Contaminated soil

A land area is called contaminated if the soil contains hazardous substances introduced as a result of human activity to the extent that these substances endanger health or the state of the environment.

Soil can be suspected to be contaminated if an exceptional smell or colour can be detected, or the soil contains large amounts of waste.

If you suspect that the soil is contaminated in some area of Helsinki, contact the City of Helsinki Environment Services’ Environmental Protection Unit in charge of soil control.

Examination of contaminated soil

The quality and scope of contaminated soil are examined with soil samples. Soil examinations and contaminated soil remediation are usually conducted when areas are planned for new uses and development begins.

The preliminary need for soil remediation and the costs for remediation are estimated, in order that they can be included in the construction budget. The soil studies and remediation plans are usually reviewed in connection of implementation planning.

Remediation of contaminated soil

The primary responsibility for remediating contaminated soil lies with the agent who has caused the contamination. Secondary responsibility lies with the land owner, and only if no other responsible party can be found, the responsibility lies with the municipality. Many cases of soil contamination are old, and no responsible party can be found, so the remediation often has to be carried out by the municipality. A notification on soil remediation in Helsinki is made to the City of Helsinki Environment Services or an application for a permit is made to the Urban Environment Committee´s Environment and Permits Sub-Committee of the City of Helsinki.

The goals of soil remediation are usually defined on the basis of a risk assessment, which is used to study the potential for transfer of various substances and the potential for sensitization case by case. Assessments of the scope of contamination and remediation needs are governed by a statute issued by the Finnish Government.

Contaminated soil can be remediated by removing either the soil or the hazardous substances, but the transfer of hazardous substances can also be prevented by isolating them, or they can be neutralized. Removed soil can be composted, burned or placed in a post with appropriate permission. Moderately contaminated soil can also be reused at waste disposal sites to cover waste.

Exposure to naturally occurring substances

Soil can contain naturally occurring substances that can be hazardous to health or the environment in high contents. Such substances include many metals, for example, lead, zinc, cadmium and mercury. Such naturally occurring substances cause background exposure.

In addition, top soil in urban environments in particular contains substances that fall out from the sky. These substances are usually spread evenly and occur in low contents. Such substances are emitted from industrial operations, power plants and transport.

The effects of fallout and background exposure are difficult to distinguish from each other, and their combined effect is urban background exposure. This is exposure caused by soil that is not contaminated otherwise, and it can be used as a benchmark to measure other contamination.   

Soil condition database

The Ministry of the Environment has established a Soil condition database based on location information. It contains data on all sites that have or have had such operations that can cause soil contamination. Remediated areas are also included in the database. The City of Helsinki Environment Services updates the data on Helsinki.

Government Decree on the Assessment of Soil Contamination and Remediation Needs

06.12.2019 18:48