Soil or groundwater can be contaminated in a variety of ways. Contamination may be caused by activities on the property, loading from elsewhere in the area, soil brought into the area or an accident. Hazardous substances can harm ecosystems or individual organisms, reduce the quality of groundwater and expose people to health problems. In addition, hazardous substances can limit our ability to utilise natural resources, such as plants and water.
According to the Environmental Protection Act, contamination and the need for remediation must be investigated if there is any suspicion of soil or groundwater contamination. The polluter bears responsibility for investigation, and this responsibility cannot be transferred to another party. If the polluter cannot be identified or held liable, or if the contamination occurs with the consent of the property owner, the property holder shall be required to investigate the contamination. In very old cases, the responsibilities are often unclear, and ultimately the responsibility falls on the municipality.
Do the following if you suspect contamination
Potential contamination within an area is often suspected in connection with the purchase of a property or construction. The earlier the contamination is investigated and found, the lower the costs of the investigation and any remediation necessary as well as fewer delays in, for example, construction work. When a suspicion arises, do the following:
- Check any information the Finnish Supervisory Agency and municipality have on the area.
- Explore the need for research – use a qualified consultant.
- Commission any necessary research.
- Submit the research results to the Soil Protection Group of the Finnish Supervisory Agency (in Turku and Helsinki, to the City). The authority will assess the adequacy of the research.
- Commission an assessment of the soil contamination and the need for remediation if thresholds are exceeded (Government Decree 214/2007).
Investigation involves several steps
In practice, investigating contamination involves investigating the operating history of the area, conducting field and laboratory surveys, and assessing environmental, health and migration risks. Investigations are conducted to assess the need for further research and, finally, the contamination of the area, environmental and health risks and the need for remediation.
Concise progress of the investigation, from site history and preliminary investigations to possible remediation. For more detailed information, see, for example, the Guide on commissioning a contaminated site remediation project.
Provisions on soil research and assessing contamination and the need for remediation are laid down in the so-called PIMA Decree, i.e. the Government Decree on the Assessment of Soil Contamination and Remediation Needs (Government Decree 214/2007).
If there is a need for remediation in the area, a sustainability assessment is finally recommended to compare the suitability and sustainability of different remediation methods for the site in question. Once this is done, the actual planning of remediation may commence.
Investigation costs
Investigation costs are affected by, for example, whether groundwater, surface water, sediment, landfill gases, dust, berries, mushrooms or fish are studied in the area in addition to the soil. The cost is influenced by numerous other site-specific conditions and a variety of other factors, such as:
- the surface area of the contaminated area and depth of contamination
- location (transport and travel costs);
- location in a groundwater or nature reserve;
- soil quality and groundwater properties;
- groundwater level
- type of hazardous substances (the analysis of dioxins and furans is expensive, while the analysis of metals and oil hydrocarbons is more economical)
- volume and operating time of the polluting activity;
- selection, quantities, concentrations, properties (migration) and depth of contaminants (affects sampling equipment)
- need for preparatory measures (e.g. clearing trees, marking cables and taking the built environment into account)
- dates and other details of the tendering process (e.g. season, market situation)
- urgency and schedule.
Existing historical data also has an impact on costs. When there is only a small amount of background information available, it can result in having to conduct research that is even unnecessary in some cases. Precise data can be used to more effectively define research.
