PFAS in Switzerland: Why a measurement alone is not a health verdict
Detections in water, food or blood matter – but only the right comparison turns a figure into a meaningful statement.
PFAS are often called "forever chemicals" because many of these industrially produced substances break down only very slowly in the environment. They are used in numerous applications, for example in water-repellent finishes, firefighting foams, packaging or technical products. It is therefore relevant that authorities detect PFAS in water, food or blood. But that does not automatically mean that an individual person faces an immediate health risk.
The reason: the collective term PFAS covers thousands of substances. Not all of them have been studied equally well, and not all of them behave the same way in the body or in the environment. Anyone who wants to assess a measured value must first ask: which substance was measured where? In what unit? And against which legal or health-based reference value?
A number needs the right comparison
A value in groundwater is not directly a value at the tap. A value in blood, in turn, is not a drinking water limit, but reflects a past cumulative exposure from different sources. A maximum level in food also answers a different question: it sets out when a product may be sold. EFSA has defined a tolerable weekly intake of 4.4 nanograms per kilogram of body weight for four particularly relevant PFAS. This scientific guidance is, however, not a limit value for tap water and not a personal diagnosis of illness.
In Switzerland, individual maximum values currently apply to drinking water: 0.3 micrograms per litre for PFOS and PFHxS, and 0.5 micrograms per litre for PFOA. The BLV reviews these rules. The EU works with a value of 0.1 micrograms per litre for the sum of 20 PFAS. The two systems should not be played off against each other: they cover different groups of substances and serve as regulatory instruments.
What the Swiss data show
The national groundwater monitoring programme NAQUA examined just under 550 measuring sites for 26 PFAS in 2021. PFAS were detected at just under half of them. The Swiss drinking water maximum values currently in force were exceeded at one measuring site. That shows two things: PFAS are widespread and local contamination deserves attention; but a detection alone is not the same as an exceedance of a limit value.
The picture for food is differentiated as well. According to the BLV, food of animal origin on the Swiss market largely complied with the applicable maximum levels in 2025; 0.8 percent of the samples tested were non-compliant. That is not a free pass for contaminated sites, but equally not evidence of a nationwide problem. The pilot phase of the Swiss health study found PFAS in blood samples from adults in Bern and Vaud. It does not, however, allow a diagnosis for individuals and is not a representative health assessment of the whole country.
What people in Switzerland can take from this
Anyone who wants to know how their own tap water is doing will get the most factual information from the local water utility or the cantonal specialist office. There, the origin of the water, the monitoring programme and any measures taken are known. A single value from another municipality cannot be transferred. Blanket recommendations for expensive household filters or blood tests would not be sound without concrete local contamination.
When it comes to eating, the BLV above all recommends variety. It reduces the risk of repeatedly taking in a pollutant from the same source. That is sensible precaution without turning every meal into a risk. What remains important: authorities, water utilities and businesses must continue their controls and explain measuring methods and limit values transparently.
The fair message is therefore neither "all harmless" nor "acute danger". PFAS are a long-term environmental and health issue. Good decisions start with clean measurements – and with correctly placing into context what a measured figure actually says.