Quality monitoring
The factors which threaten soil quality may be direct (accidental spillage of pollutant substances in the soil) or indirect (fallout of atmospheric pollutants).
In the case of accidental spillage of pollutant substances, the Safety division of Genève Aéroport, where appropriate acting in cooperation with the specialised cantonal service, is equipped with resources to confine spillage and limit its impact on the soil.
The fallout of atmospheric pollutants on the soil is determined through verifications every 3 to 5 years. Soil samples are taken at fixed distances from the runway and then analysed to determine their heavy metal (copper, cadmium, lead and zinc) concentrations and the presence of organic compounds such as polycyclic aromatic hydrocarbons (PAH) and polychloro-biphenyls (PCB).
The ordinance on soil pollution (OSol) stipulates maximum values for the concentration of pollutants in the soil. Having regard to the use of the airport site and the subsoil geology, no measured pollutant concentrations have raised any problems.
Mapping of polluted sites
In cooperation with the Federal Office for Civil Aviation (FOCA), Genève Aéroport drew up a mapping of polluted sites in order to comply with the current legal requirements. The mapping comprises waste disposal, company and accident sites. No sites within the airport enclosure have raised any particular problems.
Measured concentrations
Copper concentrations are in the medium to high range and increase the closer the samples are taken to the runway. Copper is generated essentially by wear of aircraft brake linings.
The concentrations of other heavy metals do not pose any major problem. The contents recorded near the runway do not require at present improvement measures. By analogy with the verges of highway or rail routes, pollution by heavy metals is bound up with the quantity of traffic and is unlikely to fall in coming years.
Organic compounds, in particular polycyclic aromatic hydrocarbons (PAH) and polychloro-biphenyls (PCB), which are present in quantities that are not negligible on the edge of the runway, may be generated by the incomplete combustion of fossil fuels. The results of the last verification suggest that ground contamination remains limited in extent. As the use of PCBs is prohibited today, their concentration is unlikely to increase further.