The fact that PFAS are present in food and drinking water worldwide is not new. Not a big problem, toxicologists thought until recently, the amount that people ingest is so low that it would not cause any health damage. In 2008, the European Food Safety Authority (EFSA) said it was unlikely that the amount of PFAS ingested by Europeans would lead to health problems. But in September last year, the EFSA stated in a report that the limit value – the maximum amount of PFAS a person should be allowed to ingest per week – should be lowered. RIVM is now joining in. What has changed?

The short answer is that PFAS are harmful in a different way than toxicologists previously thought. Previously, the main focus was on the risk of liver damage and thyroid abnormalities. But now PFAS also appear to hinder the immune system.

PFAS were a triumph of chemistry. The molecules, which do not occur in nature, consist of a carbon chain with fluorine atoms attached to it. They are used in almost everything that is slightly water-repellent – ​​raincoats, the non-stick coating in pans. The handy thing about this is that they cannot be broken: the bond between carbon and fluorine is very strong. But therein also lies the problem: once in the body or environment, it hardly comes out. In addition, they spread quickly through the environment: in water, air and soil.

Fluorine compounds like PFAS are the worst in a way

Jacob de Boer toxicologist

Jacob de Boer, toxicologist at VU University Amsterdam, has been concerned for years. “I have spent my entire working life trying to get halogenated substances such as PFAS out of the world. The fluorine compounds like PFAS are the worst in a way: the fluorine atom is so close to the carbon that no bacteria is able to break them down.”

PFAS already leaks out during production, especially through the air. In Dordrecht there is a factory of chemical company Chemours that emits PFAS. In 2018, RIVM already advised to eat “not too often and not too much” fruit and vegetables from the vegetable gardens within a kilometer of the factory chimneys. There are two vegetable garden complexes in that area. In Helmond there is still a polluted area around a factory, but it no longer emits PFAS. Since 2019, the same advice applies to not eat too many crops from the neighborhood. Many PFAS enter rivers via factories abroad. Near Antwerp, the ground around a 3M factory is seriously polluted.

It enters the diet from rivers via drinking water, fish or irrigated agricultural land. The concentration of perfluorooctanoic acid (PFOA) in the blood of the average European is 3.5 nanograms per milliliter, the RIVM reports. The blood level of residents around Chemours is higher. PFOA is one of the most common PFAS. In humans, the substance does not break down, and the content continues to build up during life, mainly in blood serum, until a certain balance is reached.

Harmful to immune system

If an unnatural substance accumulates in people, you need to know: how harmful is that? “At the time of the last EFSA report in 2008, toxicologists, based mainly on animal studies, thought that the toxicity of PFAS was fairly clear,” says toxicologist Ron Hoogenboom of Wageningen Food Safety Research, an institute that researches foods for PFAS, among other things. Hoogenboom was vice-chairman of the working group that wrote last year’s EFSA report. At the time, it was known that PFAS at high concentrations would be harmful to the liver. But later studies in the Faroe Islands and in Germany showed that the chemicals were already harmful to the immune system at lower levels. Such tests are not done as standard, says Hoogenboom.

Renewed attention to the health damage caused by PFAS already started before the EFSA report, in the United States in an area around a factory of chemical company DuPont. There, PFOA was discharged in large quantities, causing major health problems – including cancer – for local residents. In 2004, a farmer won his first civil case after his cattle died. Many lawsuits followed. As of 2015, local residents convinced a jury that their cancer was caused by the pollution. In 2017, DuPont agreed to pay $671 million to a total of 3,550 victims. The drama was made into a film: appeared in 2019 Dark Waters. With the extra focus on the toxicity of PFAS, the first search for effects on the immune system was also carried out around the factory, but these have not yet been clearly identified.

Those effects were found in the Faroe Islands. Researchers measured the concentration of PFAS in the blood of children who were vaccinated. Children with a higher concentration of PFAS in the blood developed fewer antibodies and T cells after vaccinations. Following this study, a German study followed. Toxicologists examined blood samples from children that had been preserved from a study from the 1990s. Again, fewer antibodies were found in children with higher blood concentrations of PFAS. The measured effect was even stronger than in the Faroe Islands. How PFAS affects the immune system in adults has so far been studied once, albeit in a small group. “That has yet to be repeated with more participants,” says Hoogenboom. “But that was a bit more difficult to set up, because adults were not vaccinated as regularly.”

PFAS therefore seem to weaken the immune system, and therefore make the vaccines less effective. It is therefore also conceivable that PFAS will influence the course of the corona pandemic, says Hoogenboom. “That could go two ways. On the one hand, PFAS could have an effect on the way your immune system fights the virus. The first studies on this are now starting to come out claiming to see those kinds of connections. They still need to be looked at closely. On the other hand, PFAS could weaken the effectiveness of vaccines.”

Build up in the body

New knowledge requires a new approach, argued the European Commission. She requested an opinion from EFSA, a 391-page report followed in September last year. In it, the institute also observes that PFAS is already harmful to the immune system at lower concentrations. The old limit value – the weekly intake that can lead to health damage – was mainly based on liver damage. Considerably more must be taken for those health effects. The EFSA reduced the maximum weekly intake of four PFAS together to 4.4 nanograms of PFAS per kilogram of body weight. The old limit values ​​differed per substance, in the case of PFOA, for example, this was initially 6 nanograms per kilogram of body weight. This limit value means that the substance continues to build up in the body during life. However, it is based on toxicity in children – a risk group.

“We then looked at the EFSA report: do we think the scientific substantiation is sufficient to also start working with this new limit value?”, says Anton Rietveld. He is head of food safety at RIVM. “The answer to that was yes. This resulted in five new reports.” Those five new reports reassessed whether the Dutch ingest too much PFAS through drinking water, food and through vegetable gardens or swimming pools in the area around Chemours.

All over the Netherlands, people appear to be overexposed to PFAS. 83 to 98 percent of all PFAS that the Dutch ingest comes from food. The rest comes in through drinking water. If you drink more water that is made from surface water, often in the western Netherlands, you will ingest more PFAS.

Should all Dutch people be concerned? Joke Herremans, head of consumer and product safety at RIVM, thinks nuance is important here. “Anyone who ingests too much PFAS in the Netherlands will probably not notice anything. Your immune system will do a little less well, but whether it leads to disease varies from person to person. If your intake is below the limit, nothing will happen. If it’s above it, there’s a chance something could happen.” Rietveld adds: “How well your immune system works depends on many factors. It already differs per person, and your lifestyle matters. Suppose your immune system is less fit due to PFAS, then you cannot possibly know what effect that has.”

European ban

What now? The RIVM comes with a number of recommendations. In the shortest term: don’t eat any food at all that grows within a kilometer of the Chemours factory in Dordrecht. In 2021, the Dutch Food and Consumer Product Safety Authority will again measure PFAS levels in 170 foodstuffs of plant and animal origin. And the Netherlands is already working with Denmark, Germany, Norway and Sweden on a European ban on PFAS. The institute also recommends adjusting the standards for PFAS in tap water, and reducing the amounts where possible.

European policy is necessary, because 70 to 80 percent of Dutch surface water comes from abroad. In the Rhine, with 65 percent of PFOA and 90 percent of PFOS, relatively much PFAS comes from abroad, says Leonard Oste, researcher at Deltares, a comment: “It is certainly not the case that the PFAS contribution from the Netherlands to the Rhine or Meuse water is lower than German or Belgian.”

“PFAS are the biggest environmental problem we have to deal with,” says Wim Drossaert, director of drinking water company Dunea and board member of Vewin, the association of water companies. Dunea is responsible for the drinking water of 1.3 million inhabitants. “PFAS has the annoying quality of being so persistent. We are sincerely concerned, because the substances are almost impossible to purify. Developing and scaling up the right techniques costs billions and takes ten to fifteen years. That’s too long. I am happy with the RIVM report, but please let’s start at the source. Stop discharging PFAS into sewers and rivers.”