PFAS in food explainer
- PFAS persist in environments and can contaminate food supplies
- Four PFAS accumulate in humans, and these are linked to adverse health effects
- Preventing contamination at source remains the most effective approach
- Soil and water treatments can reduce PFAS significantly today
- Remediation is challenging and costly but supports safer food chains
Per-and polyfluoroalkyl substances (PFAS) are chemicals that repel oil and water and resist heat. Because of their resilient chemical structure, they remain in the environment for a long time, and are known colloquially as ‘forever chemicals’. They can often contaminate food.
Their presence in food is not always harmless. The chemicals have been linked to a number of negative health outcomes, including thyroid disease, liver damage, increased cancer risk, and fertility issues.
A risk assessment by the European Food Safety Authority (EFSA) found four PFAS – PFOS, PFOA, PFNA and PFHxS – that are known to accumulate in the human body. According to EFSA, these four are linked to adverse health effects, including to the immune system. For other PFAS, more research is needed.
PFAS make their way into food in a variety of ways, including through pesticides and contamination through soil and water.
Can PFAS be kept out of food?
PFAS cannot be easily removed from food, explains a spokesperson for EFSA.
The best way of keeping them out of food is instead to prevent them from entering it in the first place. “Reducing PFAS contamination at its source is the most effective way to lower levels in the food chain”, says the EFSA spokesperson.
Of course, due to the ubiquity of PFAS, this is difficult. “PFAS are extremely persistent and can remain in the environment for long periods”, stresses the EFSA spokesperson.
Several methods exist to remove PFAS from soil and water.
How to keep PFAS out of food
The removal of PFAS from soil and water is difficult. Often, not all PFAS can be removed. Nevertheless, methods exist to radically reduce it.
According to the European Environment Agency (EEA), PFAS can be removed from soil using a combustion-based treatment, often at very high temperatures. This is the only way to remove PFAS from soil entirely, the EEA says.
Some PFAS can also be removed through soil washing, a method which includes washing soils with chemical solvents. According to the EEA, the effectiveness of this method depends on the soil composition: PFAS can be removed in this way from granular soil, but not from more cohesive soil types such as clays.
Meanwhile, PFAS can be removed from water by adsorption onto activated carbon. Adsorption is where molecules stick to the surface of a material.
Activated carbon is an effective adsorbent, as it’s porous and provides a large surface onto which contaminants may adsorb, according to the United States Environmental Protection Agency. Activated carbon is made from materials with high carbon contents, such as wood and coal.
Another method is reverse osmosis, a process where water moves through a semipermeable membrane. This can remove a wide range of PFAS with high efficiency, according to German machine manufacturer Herco Wassertechnik GmbH, but leaves a residual stream that must be treated afterwards.
Electrochemical oxidation, which uses electrical energy to drive the oxidation – and therefore degradation – of contaminants, has been shown as an effective method to remove 99% or more of PFAS in water. However, it is costly and energy intensive.
Removing PFAS from soil and water is not easy. Yet it can be done. If industry wants to mitigate the presence of forever chemicals in food, investing in its removal from the source is a good place to start.
