Understanding the Impact of Forever Chemicals on Food and Water
Liz Moran, Director of Technical and Quality at Eurofins Food & Water Testing UK, discusses the dangers of PFAS and the analytical efforts being made to improve food safety
| 4 min read | Interview
What are PFAS and how are they making their way into our food?
Per- and poly-fluorinated alkyl substances, or PFAS, are a family of around 4,800 synthetic substances that are not naturally present in our environment. They are used in everyday products, such as stain and grease-repellent coatings like Teflon and paper food packaging, and have appeared in almost all foods and drinking water. They bio-accumulate in aquatic and terrestrial food chains and have high mobility in water, which means they can’t be removed by conventional drinking water or wastewater treatment. The contamination of food with PFAS is likely to have been as a result of using water in the production and manufacturing process or via bioaccumulation in livestock, including crops, silage, and grass grown on sludge-fertilized fields, as well as fish, shellfish, and meat.
What are the potential harmful effects of PFAS on humans and the environment?
Some PFAS are associated with adverse effects on the immune system, low infant birth weights, cancer, and thyroid hormone disruption. The detection of PFAS and prevention of contamination has never been more important.
What is being done to address the issue of PFAS in food and water?
The UK, US, and EU prohibited the production and use of perfluorooctanesulfonic acid (PFOS) over 20 years ago, but other PFAS compounds have not been banned and are still widely used today. They are also listed in Stockholm Convention as Persistent Organic Pollutants, and the UK Environment Agency mentions PFAS in its chemical investigation programs. There are also upcoming requirements for utilities companies to start looking for them in recycling plants as well as in drinking waters. The EU Commission limits PFAS in drinking water to 100 ng/l for the total of 20 identified PFAS compounds (PFAS 20) and 500 ng/l for total PFAS (the Directive covers 20-25 compounds). The European Food Safety Authority has also published a new directive which recommends a maximum limit of 4.4 ng/kg bodyweight per week (sum of 4 PFAS).
What are some of the analytical challenges involved in detecting PFAS?
The main challenges in testing for PFAS include achieving selectivity, sensitivity and inclusivity. Moreover, contamination issues from the environment can interfere with analysis at ultra-low levels. Additionally, there is a shortage of commercially available standard materials to expand and cover all the components. The need to test for an extremely low limit of quantification (LOQ) also poses a challenge as it requires concentration many times, which increases the risk of blank levels.
How has testing for PFAS improved in recent years?
Until recently, laboratory instruments were not sensitive enough to detect the very low levels of PFAS present in food and water. Now, testing is carried out on water and food by liquid chromatography with tandem mass spectrometry (LC-MS/MS) using isotope dilution. With growing regulatory requirements around the world to detect extremely low levels of PFAS, water testing is now commercially available. Food testing is also now available, with testing ongoing in readiness for regulations to come into force. The foods most likely to be the main focus of PFAS food testing initially are expected to be those containing higher levels, including fish, meat, and eggs. Infant formula and baby food are also likely to be areas of concern and testing has recently become available for these foods.
What makes LC-MS/MS with isotope dilution well-suited to PFAS? And are there any advances on the horizon?
Isotope dilution is almost exclusively employed with mass spectrometry in applications where high accuracy is demanded. In addition to high-precision analysis, isotope dilution is applied when low recovery of the analyte is encountered. LC-MS/MS with specific internal standards for all tested PFAS is the dominant technology.
On the horizon: High resolution mass spectrometry (HRMS) is a complementary technique to support PFAS analysis. Eurofins in Australia is working with this. It won’t replace the LC-MS/MS method, but will be useful as a complement – particularly when the reference libraries for it are bigger.
What is your overall assessment of the situation – and where do we need to go from here?
Although not acutely toxic at the levels we currently see, it’s clear that PFAS are endemic in the environment and many parts of our lives, including the water we drink, the food we eat, and even the pots and pans we cook our food in.
The long-term impact that prolonged exposure to PFAS will have on our health and the environment is a growing concern around the world. The requirement for testing PFAS will increase in the months and years to come to help monitor and control the levels in our food and water. What is not yet clear though is which, and how many of the very large PFAS family, are toxic to health, or how we can control the use of it around the world to prevent worsening the situation. As more research is conducted, we hope to be able to answer some of these lingering questions.
