Construction projects at the airport sometimes also impact areas referred to as "conservation-worthy habitats". Ecological compensation measures must be implemented as a result. Following consultation with the canton and the Swiss Confederation as well as extensive planning work in areas belonging to the municipalities of Rümlang and Opfikon, work began on a compensation measure of this nature in early 2025. A 3.2-kilometre-long, currently canalised section of the Glatt River is to be transformed into a near-natural river, or renaturalised.  

Soil samples were taken systematically throughout the construction site due to the ongoing nationwide debate about PFAS pollutants in soils. This sampling revealed that soil previously used as farmland as well as soil in the banks of the Glatt River are contaminated with PFAS. The measurements vary depending on the location's proximity to the water and previous agricultural use. Studies carried out by the Building Department have shown that PFAS can be found in soil nearly everywhere in the Canton of Zurich.  

PFAS have been used in a wide range of different applications and products, including paints, ski wax, electronics, non-stick coatings, cosmetics, pesticides and outdoor clothing since the 1970s, and end up in the environment in a variety of ways, where they hardly break down. They enter waterways in many ways, including through treated wastewater or the once common practise of spreading sewage sludge with pesticides on farmland soil.  

First stage of construction will be completed, after which the project will be suspended  

The areas affected by the "Glatt revitalisation" project are located outside the airport's perimeter. There is no proven link between the level of contaminants found in the soil and the airport or flight operations. The project area and therefore the affected soils are located west of the airport and have been largely used for agricultural purposes in the past.  

Work on the first stage of construction in the Eichhof area between Neue Rohrstrasse and the Rümelbach's feeder stream has been underway since April. Since the pollution levels found there are not very high, a large portion of the soil already excavated can be recycled. Zurich Airport Ltd. will therefore complete construction of this section by the end of 2026. Responsibility for the additional costs has yet to be clarified.

Project's future hinges on political decisions  

Legally, the question of how to deal with PFAS-contaminated soil still remains unanswered. Many soils are contaminated with PFAS and are classified as hazardous waste when disposed of, which results in enormous additional costs. Since the legal situation is unresolved, Zurich Airport Ltd. has decided not to take any decisions regarding the further stages of the project until the legal framework has been clarified regarding how to deal with PFAS-contaminated soil in future. Zurich Airport Ltd. regrets that the revitalisation project cannot be implemented as planned and hopes for swift political decisions on how to deal with PFAS at the federal level.  

Further information on the project