One of the key findings of the research was the advanced analytical techniques that made it possible to detect PFAS at very low concentrations in drinking water. “We looked at 56 types of PFAS, whereas typically, 12 types are examined,” explains Mohammad Sadia. “This creates a powerful analytical method, which can give us more power to analyse low-levels of PFAS in drinkwater places and sources. Which is essential for monitoring water quality and taking appropriate measures.”

Concerns about groundwater
The research also mapped the spread of PFAS in various types of water sources in the Netherlands. It was found that medium- to long-chain PFAS (C4-C14) are present in significantly higher concentrations in surface water than in groundwater. This difference is related to how PFAS move through the soil and how they bind to particles in the water.

Notably, the presence of very short-chain PFAS—such as trifluoroacetic acid (TFA)—was observed in Dutch groundwater. These types of chains are still poorly studied. “This raises the question of whether existing guidelines for PFAS in drinking water offer adequate protection against these substances,” says Sadia. “More research is needed to understand the health risks.”

Impact on drinking water production
Historically, PFAS has long impacted the quality of drinking water. Firefighting foams used during drills and landfill leachate from PFAS-containing waste contribute to soil and groundwater contamination, posing long-term risks due to PFAS persistence in the environment.

Removal of PFAS
The study also examined current methods for removing PFAS from drinking water. Traditionally, PFAS is often filtered using granular activated carbon (GAC), but it turns out this method is less effective than previously assumed. GAC works in many cases, but in some situations, it is insufficient to lower PFAS levels to safe concentrations. “We found that active Carbon removal is not sufficient enough to remove the PFAS in the concentration that is required at the moment. Reverse Osmosis (RO) is a promising technology for removing PFAS,” explains Sadia. “The chemicals stay trapped in the plastic membrane filter, and the liquid can still pass through.”

Stricter regulations
The study concludes that urgent action is needed to address PFAS contamination in drinking water. Existing regulations sometimes still allow industries and pharmaceuticals to use PFAS. If PFAS continues to be used in products, they can enter the environment through industry, which jeopardizes drinking water quality.

The sensitivity and precision of the new measurement and removal methods provide new opportunities for determining and improving drinking water quality. “To understand the presence of PFAS is good help, to help different or new guidelines.” Says Sadia. This enables policymakers or government agencies, such as the RIVM (National Institute for Public Health and the Environment), to take more effective measures against PFAS contamination. After his defense, Sadia plans to look into human exposure to all kind of chemicals. “starting with PFAS, but branching out to all kind of chemicals.” 

Defence details

Mohammad Sadia. PFAS From Source to Tap. Analyzing PFAS in the Drinking Water Cycle and Ensuring Safe Consumption. Supervisor is Prof. A.P. van Wezel. The co-supervisors are Dr A. Praetorius and Dr T.L. ter Laak.