Contaminated sites: In brief

All contaminated sites are listed in registers that are freely accessible to the public. Almost two thirds of the investigations have been completed, and more than 1,600 sites have been remediated. Collaboration between the federal authorities and cantons is going well. The remediation of the three major hazardous waste landfills in Monthey, Bonfol and Kölliken is complete. However, there are still nearly 2,400 sites that need to be remediated, including several large landfills. In order to comply with the Swiss Federal Council's explanatory report on the Contaminated Sites Ordinance, all investigations should be completed by 2028 and all remediations by 2040.

1. Uncontrolled waste disposal (drivers)

Old landfills, polluted industrial areas and sites where accidents occurred bear witness to uncontrolled handling of wastes in the past. Waste disposal and treatment were dealt with as cheaply as possible. At the time, however, environmentally-friendly waste disposal was not always possible. For example, combustible hazardous wastes were dumped into worked-out gravel pits, or toxic production residues were discharged onto unsealed ground within plant compounds.

Current legislation should ensure that no new contaminated sites are created, with the exception of unpredictable events like accidents.


2. Escape of hazardous substances into the environment (pressures)

Hazardous substances can escape into the environment from landfills, plants, shooting ranges or accident sites.

  • Pollutants from such deposits commonly leach into underground or surface waters. Sixty per cent of the polluted sites are located in water protection areas, i.e. above useable or used groundwater bodies.
  • Pollutants end up in the soil (e.g. heavy metals such as lead and antimony at shooting ranges).
  • Other sources of pollution are gases emitted into the air from municipal landfills.

3. Number of polluted sites (state)

There are approximately 38,000 polluted sites in Switzerland. Of the sites needing investigation, almost around 11,600 have been assessed in relation to their monitoring or remediation requirements. It may ultimately be assumed that approximately 4,000 sites pose a threat to humans or the environment, in other words they are contaminated sites and must be remediated.

Some 1,600 of the estimated 4,000 contaminated sites have been remediated. Remediation is underway at most of the sites that require it urgently. Work has been completed, for example, at the Pont Rouge landfill in Monthey and the large Bonfol and Kölliken hazardous waste landfills.

4. Environmental contamination, danger to the public, high remediation costs and economic losses (impact)

Hazardous substances escaping into the environment from a contaminated site can cause acute or chronic illness in human beings.

Such substances are also a threat to water, soil and air. The impact is most often seen in the groundwater.

Certain substances are quite mobile and long-lived. Fortunately, however, there are also numerous pollutants that are degraded by natural processes over a span of years or a few decades.

Contaminated sites are a grave problem for Switzerland in particular, because population density is very high here. Many polluted sites, moreover, lie in the immediate vicinity of sensitive groundwater formations.

One estimate puts the aggregate cost of cleaning up contaminated sites at roughly CHF 5 billion.

Because of the possibility of contamination and the associated cost consequences, many investors in new construction projects prefer «greenfield» sites over brownfields even if they are well developed. In most cases, however, contamination is not objectively a major obstacle.

5. Contaminated site management (Responses)

The federal authorities are committed to ensuring that no dangerous contaminated sites will be passed on to future generations. The Environmental Protection Act (EPA) and Contaminated Sites Ordinance (CSO) provide the legal basis for the work of the FOEN in this regard.

Thanks to the OCRCS Contamination Fund, the federal authorities can provide support for the remediation of contaminated sites to the tune of up to CHF 40 million annually. The FOEN ensures that the risks to humans and the environment arising from contaminated sites can be eliminated in the long term and sustainably in accordance with the principle of dealing with pollution at source.

Today, the 38,000 polluted sites are fully recorded in the federal and cantonal registers. All surveys sites that require evaluation should be completed during the coming years. These surveys are intended to provide a decision-making basis to establish which sites require monitoring or remediation.

  • All investigations should be completed by 2028;
  • All contaminated sites should be remediated by 2040.

Thanks to the legislative provisions on waste management, which were enacted by the federal authorities in the 1990s, no more contaminated sites should arise in future:

  • These provisions include, for example, the regulations on the prevention of landfilling of hazardous waste and the ban on the disposal of untreated municipal solid waste in landfills from 2000.
  • The infrastructure for recycling and treating waste prior to disposal was developed at the same time.

Further information

Last modification 26.04.2022

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