First analysis of Swiss soils for the harmful PFAS chemicals
The ZHAW was involved in a soil analysis which revealed the widespread presence of PFAS. Sometimes referred to as forever chemicals, these harmful chemicals can have a negative effect on human health.
The chemicals are called PFAS for short. This acronym stands for per- and polyfluoroalkyl substances and comprises an entire chemical class with over 10,000 substances. Due to their water- and oil-repellent properties, they have been used for decades in numerous industrial processes and products worldwide, for example in cleansing agents, outdoor clothing, pan coating, ski wax and fire-fighting foams. However, many PFAS are extremely persistent and can now be detected in the environment, in the food chain and even in human blood. The main source of human intake is food and water.
PFAS found in all samples – lower contamination in the Alps
On behalf of the Federal Office for the Environment (FOEN), the School of Life Sciences and Facility Management worked hand in hand with the Agroscope agricultural research centre to systematically investigate the levels of 32 PFAS compounds in Swiss soils for the first time. The two compounds PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) were found in all 146 samples. The chemicals have been banned in Switzerland and the European Union. The samples were taken from different regions as well as climate zones and from soils used for different purposes.
However, it was not possible to find a direct link between the concentration profile and the land use. Although alpine locations had the lowest concentrations, PFAS were also found in remote areas of Switzerland. According to Basilius Thalmann from the Institute of Natural Resource Sciences (IUNR), it is not clear how these substances got into the environment. For the more contaminated soils, the fact that sewage sludge used to be used as fertiliser on fields might have played a role. The extent of the risk to humans and the environment cannot yet be assessed conclusively. In experiments with animals, some of the PFAS substances have been shown to have a damaging effect on the liver, reproduction and immune system. In Switzerland, threshold values for PFAS substances in soil, water and food are being developed in collaboration with the ZHAW.
Study about per- and polyfluoroalkyl substances in Swiss soils