Stop eating eggs from chickens in the vegetable garden or the petting zoo. The National Institute for Public Health and the Environment (RIVM) issued this drastic advice on Tuesday, after the first large-scale study in the Netherlands into PFAS in chicken eggs. The conclusion is that they contain excessively high concentrations almost everywhere.
PFAS are a collection of chemical substances that hardly break down and can be toxic. After the RIVM concluded in 2023 that eggs in the vicinity of the Dordrecht Teflon factory Chemours contained dangerously high amounts of PFAS, a national study was decided upon.
The researchers collected eggs at sixty locations to investigate how harmful it is to eat them. These locations are spread across all twelve provinces, from Northeast Groningen to the southernmost tip of Limburg. At only one location, near Assen, the researchers found no PFAS.
1. How is it possible that the eggs are contaminated in so many places?
It was already clear that PFAS are everywhere. Increased concentrations have been measured in numerous locations in recent years. The same property that made PFAS – used in electronics and non-stick pans, among other things – a success, ensures that the substances have accumulated in the environment for decades: they are non-degradable.
Factories worldwide have emitted and discharged tons of PFAS. It settles in seas, rivers and soaks into the soil. In addition, numerous other sources locally cause increased values in the soil. Think of fire brigade training locations, defense sites, landfills and places where foam parties have been held.
2. How do PFAS reach the eggs?
Based on previous studies, the RIVM suspects that earthworms transmit PFAS. They crawl through contaminated soil and are then eaten by chickens. In addition, chickens also peck and scratch around in the contaminated soil and drink contaminated water.
The RIVM is conducting a follow-up study to definitively trace how PFAS ends up in the eggs. The results are by expected in the autumn.
3. What quantities did the researchers find?
Of the sixty locations selected by the RIVM, people at 31 locations already ingested too much PFAS with one egg or even less per week. At ten locations, people can eat a maximum of one egg per week without exceeding the limit value. At nine locations, people can eat more than four eggs per week without exceeding the limit value.
It is certain that increased PFAS concentrations have been found at almost all locations. In addition, it is not possible to read from the outside how much PFAS is in an egg. "We cannot say in advance: that egg is safe," says Polly Boon, one of the researchers at the RIVM. "For that reason, we advise against eating eggs anywhere in the country."
4. What happens if you do eat eggs from your own chicken coop?
If people ingest quantities of PFAS that exceed the limit values for a long period of time, this can be harmful to their health. Some of these substances affect the immune response: you get sick more quickly, because your body is no longer as effective against viruses and bacteria, and vaccines no longer work as well.
The RIVM points out that eggs are not the only way in which people ingest PFAS. Other foods and drinking water already contain more PFAS than is healthy for a human. "We already ingest too much PFAS," says Boon. "If you do eat the eggs, you increase that by a considerable amount. Then the chance of illness increases."
According to the RIVM, eggs from the supermarket can still be eaten - they usually score considerably better in measurements. How that is possible is not exactly clear. It may have to do with the fact that commercially kept chickens often do not walk outside and are given controlled feed.
5. What about other crops from the vegetable garden?
The RIVM has a reassuring message about this: fruit and vegetables can be eaten with confidence. Eggs contain considerably more PFAS than other crops from the garden. This has to do with the fact that PFAS bind to proteins, which makes it easier for eggs to absorb the chemical compounds.
“The advice only applies to eggs,” Boon emphasizes. “People can still safely eat their vegetable garden crops.”
