Non-polymer PFAS can build up in blood protein of animals, and is not always removed quickly. This means that predators eating PFAS-contaminated food will have higher levels in their bloodstream, and concentrations can increase up the food chain. Studies suggest that build up of PFAS is similar to those of other Persistent Organic Pollutants such as DDT.PFAS are estimated to be settling in arctic regions at rates of tens to hundreds of kilograms per year (25-850kg per year), depending on the specific PFAS chemical in question. Certain PFAS are released as gases to the environment and are blown a long way by wind and air currents in the atmosphere,. These gas PFAS will over time degrade to more persistent chemicals like PFOS and PFOA. This may be one reason why PFAS of environmental concern have been found in remote regions such as the Arctic as well as near PFAS production sitesPFAS including PFOS and PFOA have been found in air samples around Europe. The chemicals are found in small quantities, but appear in almost all samples tested. PFAS enters the atmosphere both from factories and the air inside our homes. PFAS is found in treated waste water from industrial and domestic sources and has been found in both rivers and groundwater. Conventional drinking water processes will not remove PFAS.PFAS-coated clothes that are thrown away will often end up either incinerated or in landfill. Unless incinerated at very high temperatures (>1000oC), fluorinated polymers could release more harmful PFAS during burning. PFAS of environmental concern have also been found in landfill leachate. Non-polymer PFAS are used in the production of fluorinated polymers. The manufacture of stain-resistant finishes generally releases these PFASs into the environment, both by air and water emissions. They are very hard to remove during water treatment. Workers in textiles factories are some of the population most exposed to these potentially harmful chemicals. Small quantities of PFAS will be removed during wash and wear of products containing PFAS. This includes fluorinated polymers used on stain-resistant coatings, and non-polymers that remain on clothes after production (Lassen et al. 2015).Most UK waste still ends up in landfill, and this includes PFAS-containing products. Studies have shown that the liquid coming from landfills (known as leachate) often contain non-polymer PFAS chemicals. In the USA the total quantities were estimated at 563-638 kg in 2013. To properly break down PFAS chemicals high temperature (1000oC or more) incineration is recommended. Incineration of municipal waste does not necessarily reach these temperatures (min temp. required is 850oC), and the incomplete breakdown could release non-polymer PFAS.Wash and wear of clothing that contains PFAS-based stain-resistant or water repellent finishes release PFAS to the environment. Coatings are thought to lose effectiveness after 20-30 washes. This can include non-polymer PFAS, remnant from production or as a break-down product of side-chain polymers (Lassen et al. 2015). The manufacture of stain-resistant finishes releases PFAS into the environment, both by air and water emissions. PFAS are very hard to remove during water treatment. Industrial emissions are estimated to be the biggest source of these chemicals to the environment.

PFAS is most definitely on the menu, but should we be worried?

European Food Safety Authority releases it’s latest scientific opinion on PFAS in our food, highlighting its effects on our immune system as a key area for concern.

In 2018, the European Food Safety Authority (EFSA) published an Opinion on two particular types of PFAS, PFOS and PFOA, suggesting levels safe for human consumption that were 80 and 1750 times lower, respectively, than their previous estimates a decade earlier. The chemicals themselves have not changed, neither have the effects they have on our health or environment, we simply allowed industry to use them before we had reliable scientific information on the consequences.

Recognising that PFOS and PFOA represent only two species in this group of well over 4700 chemicals, the panel were tasked to broaden the scope of their assessment and consider the impact of mixtures, i.e. what happens when we’re exposed to multiple of these chemicals at the same time. What is the impact of exposure to PFAS, as a full group, not a single species?

Initially, the new assessment considered 17 different PFAS, however, with very limited scientific research on even this small subset of species, the final risk assessment was limited to just four PFAS: PFOS, PFOA, PFNA and PFHxS. Recommended tolerable daily intake for PFOA has gone from 1500 ng/kg bw/day in 2008, to 0.86 ng/kg bw/day in 2008; EFSA  now recommend no more than 0.63 ng/kg bw/day for all 4 PFAS combined.

Are PFAS a problem?

PFAS are not easily expelled by the human body, this means that when we consume them, they stay with us. If we consume more tomorrow, the concentration builds, and the next day, and the next, and so on. The estimated half-life for PFAS in our bodies, i.e. the time it takes for the total concentration to half, can be up to several years for some PFAS (such as PFOA, PFNA, PFDA, PFHxS or PFOS). What we eat today could still be in our bodies for many years to come. But are they impacting our health?

Yes. EFSA’s new scientific opinion lists a number of health concerns linked to PFAS exposure, drawing particular attention to effects on our immune system. The panel describe associations with both a ‘reduced antibody response to vaccination’ and an ‘increased propensity for infection’. Whilst this is considered a ‘risk factor’ for disease, rather than a disease itself, it’s a finding that will undoubtedly hit a nerve in today’s political climate.

The panel also highlight evidence for an association with increased levels of cholesterol and a causal link to low birth weight, the long-term effects of which are still unclear.

The list of associated human health impacts is not assumed to be complete or comprehensive, rather a list of those that can be confidently concluded with the current scientific evidence. In fact, many of the panel’s recommendations point to further research needs. Animal studies have shown links to a range of further impacts including changes to the liver, thyroid and testosterone levels, increased fetal and neonatal mortality, developmental neurotoxic effects, and an increase in tumour development. How these impacts translate into humans or wildlife is still largely unclear.

Furthermore, the risk assessments in this report are based on only four species of PFAS, contributing only 46% to the sum of all PFAS for which exposure was calculated. We currently don’t have enough evidence to assess the risk for the remaining 54% of PFAS to which we know we’re exposed.

How much PFAS are we exposed to?

The question of exposure very much depends on who you are, where you live and where you work. For example, the report shows clear differences between age-groups, with toddlers and other children having approximately twice the intake level of older age groups. For young children, the larger intake is thought to be caused by increased ingestion of house dust, from behaviours such as crawling on floors and mouthing toys and other objects. One study highlighted in the report suggested that, in a typical two year old, 36% of the PFAS they ingested came from dust, 42% from food, 20% from drinking water, 2% from absorption through their skin, and less than 1% from breathing outdoor air. This PFAS is then widely distributed throughout our bodies, with highest concentrations generally found in our blood, liver and kidneys.

The report also points to a number of key occupational risk groups, including fluorochemical production workers, firefighters and professional ski waxers, as well as geographical risks linked to heavily contaminated drinking water or specific pollution events.

How is PFAS getting into our food?

Key sources of exposure to PFAS are listed as drinking water, fish, fruit, eggs, and egg products, with meat and meat products also relatively high in PFOS and PFOA. Prenatal infants are exposed to PFAS in utero, and postnatally they receive PFAS through breastmilk.

Food packaging is thought likely to contribute to human exposure to PFAS, however the report refers only to the direct transfer from food contact materials to the food itself. Of wider importance is how PFAS ends up in the plants and animal products we consume, and this is considered to be primarily bioaccumulation.

PFAS are released into the environment during production, use and disposal, passing through wastewater treatment, leaking from landfill waste and being deposited on the ground surface directly from the atmosphere. PFAS are widely detected in drinking water and have now been detected in more than 90% of all European rivers investigated. Environmental contamination is widespread and growing. Plants take PFAS up directly from the soil and water and pass this through both natural food webs and agricultural food chains. Wherever in the world we use PFAS, and for whatever function, it finds it’s way to our drinking water, our house dust and our food, and while we know some groups are affected more than others, we’re all exposed!

And finally…

The panel recommends additional studies that look at our exposure from sources other than food, highlighting, in particular, PFAS that are found in high concentrations in indoor dust, and also recognising gaps in knowledge on the effects of cooking and processing food.

At Fidra, we’d like to highlight that the risks in this study relate to only four PFAS species, we’d like to understand the risk that the thousands of other chemicals within this group pose to our health, wildlife and environment. And, we’d like to ask why chemicals we know so little about are allowed to find their way into our food in the first place.

Click on the link below to read the full Scientic Opinion, and don’t forget to follow @FidraTweets to keep up to date on what we’re doing to prevent PFAS pollution here in the UK.

Dr Kerry Dinsmore, Fidra