Restoration of contaminated soil and landfill sites

The most significant restoration sites with contaminated soil that are tended by the City are the Verkkosaari and Hakaniemenranta areas and the plot for the We Land construction project in Ruoholahti.In addition to the large projects, several individual small sites were inspected and restored in 2021. Soil was restored at, approximately, 40 different locations. 

The soil restoration was usually carried out during the other construction work in the areas. The soil condition database created by the Ministry of the Environment features the details of 900 areas in Helsinki where research has shown the soil to be contaminated, where the soil has been assessed as being potentially contaminated or where the soil has been restored. 

Former landfill sites in Helsinki are restored pursuant to environmental protection legislation. The restoration of the Vuosaari landfill continued. The City is also preparing to restore the Iso-Huopalahti landfill site in the coming years. Reservations have also been made for the follow-up care of landfills.

The soil was cleaned in the same way as in previous years, to the extent required to achieve the objectives set for construction and restoration, and, primarily, by excavating the soil containing harmful substances and transporting it elsewhere for appropriate processing. Soil was also restored by isolating the contaminated soil on site. Below is an overview of how the contaminated soil matter was transported for treatment or final disposal in Helsinki in 2018–2021.

In 2021, a total of 100,100 tonnes of contaminated soil was transferred from the City’s restoration sites to be processed or disposed of, which is approximately 67% less than in the previous year. The costs generated by the restoration of contaminated areas and landfill sites decreased from the previous year. 

In 2021, 1,500,000 tonnes of unspoiled excavated earth were used at public construction sites. 81,728 tonnes of unspoiled excavated earth were delivered to external recipients. 

Table 10. The contaminated soil transported for treatment or final disposal from the City’s restoration sites, as well as the costs incurred by the City from the restoration of contaminated soil and landfills in 2018–2021.