The National Institute for Public Health and the Environment (RIVM) has derived new risk limits for PFAS in surface water. The guiding principle for these limits is that people should be able to consume fish sourced from surface water throughout their lives without ingesting excessive levels of PFAS. The new limits make clear that far lower levels of PFAS in surface water can be tolerated than existing standards suggest. This is because EFSA has concluded that PFAS are harmful to health even at lower levels of ingestion. The Ministry of Infrastructure and Water Management is entitled to decide to adjust the standards for PFAS in surface water, in part on the basis of this research.
New method of calculation
EFSA considers four PFAS. RIVM has developed a method of calculation (RPF method - link to document on website) that enables the risks posed by several PFAS to be calculated. After all, PFAS are nearly never found as discrete substances, usually occurring as mixtures of various types of PFAS.
The method compares the toxicity of an individual PFAS with that of PFOA. Each type of PFAS can therefore be expressed as a quantity of PFOA. When added up, this total quantity of PFOA can be compared with the risk limit for PFOA.
Hence RIVM is translating EFSA’s calculations into the mixture of many more types of PFAS in surface water. The risk limits currently calculated by RIVM for PFOS, PFOA and GenX substances are much lower than existing surface water quality standards. Water often contains other PFAS than just these three, thereby increasing the risk presented by the overall mixture. PFAS concentrations exceeding the newly calculated risk thresholds have been detected in surface water.
PFAS are man-made substances. There are over 4,000 types of PFAS in total. They do not naturally occur in food or drinking water. Emissions from factories and use in fire extinguishing equipment (for example) have caused the substances to end up in our living environment and thus in our food and drinking water. Ingesting levels of PFAS in excess of the health-based guidance value can be harmful.
Reducing the quantity of PFAS entering our living environment is important. Which is why RIVM has been commissioned by the Ministry of Infrastructure and Water Management to collaborate on a European proposal to limit the production, use and sale of PFAS. As PFAS break down extremely slowly, they remain in our living environment for many years. Consequently, the government is also doing its utmost to minimise human contact with these substances. Our understanding of PFAS and their effects on human health is still growing. RIVM is engaged in research on such topics as PFAS in soil, in drinking water and in vegetable gardens.