Groundwater and soil

FTIA’s goal is to reduce the harmful effects of infrastructure maintenance and transport on the soil and groundwater.

360 km of the railway network is located in category I groundwater areas that are important for water supply, while 200 km is located in category II groundwater areas. 5970 km of the road network is located in category I groundwater areas, and 2670 km is located in category II groundwater areas. Road maintenance groundwater risks result from the transport of dangerous goods and anti-skid treatment.

The road network has traditionally been located on ridges. However, the soil in these areas is very water-permeable, and the salt and other substances used for anti-skid treatment can easily pass into the groundwater. The groundwater risks caused by road maintenance and traffic are greatest on busy main roads.

Slippery road conditions are prevented in the winter season by applying salt or sand to the roads. Salting volumes have been reduced from the peak years of the 1990s, but the variations in the winters are reflected in the amount of salt used. In road maintenance, the concentration of chloride in groundwater is monitored nationally in cooperation with the environmental administration. There are around 230 monitoring points, and samples are taken 2-4 times a year. 

Soil and groundwater contamination in railway yards is a key environmental risk in track management

The soil contamination risk from track management is high at old refuelling sites, close to fuel tanks and oil sumps, on sidings for diesel-based rolling stock, on chemical wagon shunting tracks and in railway switch areas. Former railroad tie impregnation plants and other chemical treatment areas also pose significant risks.

The greatest risk of groundwater contamination arises in the transport of dangerous goods, especially chemicals. The largest number of chemical transports are in the Kouvola, Hamina, Kotka and Vainikkala railway yards. The risks of accidents in the transport of dangerous goods are reduced through advanced planning, for example by removing level crossings, expanding access control and developing and supervising regulations concerning equipment and transport.

Track management work has involved the development of the risk management procedures and risk assessment model for groundwater areas within the railway network. Site cards have been created for groundwater areas, and these serve as a key source of information when examining groundwater issues that relate to track maintenance. Action recommendations and monitoring data are also recorded on the site cards. The groundwater status is monitored in identified risk areas and as part of improvement and renewal projects and the restoration of contaminated land. FTIA reports on the monitoring results to the environmental authorities and develops its monitoring based on the observations made.

FTIA investigates and restores areas with contaminated soil

As part of the planning and construction of traffic route projects, investigations are made of the history of the use of the traffic route areas, including gathering information on any soil areas that are contaminated or contain harmful substances. In addition, any areas of old contaminated soil or soil contaminated by accidents are investigated and restored as separate projects. The need for restoration work is assessed using case-specific risk assessments which take into account environmental, health and transport risks. The contaminated areas are restored either as part of the projects implemented or through ensuring that some other body responsible for dealing with the contamination carries out the restoration work. As a rule, the restoration costs are paid for and the restoration work carried out by the polluter themselves, if they have been identified.

During the past few years, soil areas have been cleaned up at dozens of sites in cooperation with the transport contractor, the maintenance provider and the environmental authorities. The restoration of the soil in the former Mikkeli impregnation plant is one of the ongoing extensive restoration projects. There are also individual sites in road areas where soil cleaning is needed. In some cases, contamination that has taken place on an adjacent property has also spread to the road or rail area.

Vegetation management is carried out both mechanically and chemically

Pesticides are used in both road and track maintenance to improve visibility and safety and, for example, to prevent frost damage. In particular, the pesticides that were permitted for use in the 1980s and 1990s, along with their permanent degradation products, have proved problematic later on. A study completed in 2007 found that 15 groundwater areas had levels of pesticides or their degradation products that exceed the limit. However, the WHO's health-based recommended limits for household water were not exceeded in any groundwater area.

Pesticides degrade slowly in Finland's groundwater, and the observed pesticide concentrations may also be derived from the use of pesticides by other operators. Today, no pesticides are used for track maintenance in groundwater areas, as the work is instead carried out mechanically. The use of pesticides is also being phased out for road maintenance in groundwater areas.

Groundwater protection

Groundwater protection is constructed primarily for roads. For the roads, the protection can be built either as part of another construction project or as a separate project. Due to the scarcity of funding, groundwater protection has primarily been built in recent years only as part of major development projects.

Construction or planned construction of groundwater protection has been carried out only for a few new track sections. According to the figures, the risks to groundwater and surface water on switch-free railway lines is very low. In addition, there have been no records in recent times of significant individual accidents that have led to groundwater contamination in railway yards either.

When building new roads and railways or upgrading old ones, the need for and scope of groundwater protection is determined on a case-by-case basis, as there are many factors involved. The need for and scope of protection, as well as the methods used, are usually determined on the basis of groundwater surveys and risk determination and on the interaction between the person responsible for the project, the designer, the regional ELY Centre and the water user. Measures to improve traffic routes usually reduce the risks to groundwater and surface water in and of themselves, as the risk of accidents is usually reduced by these projects.