Ultra-short-chain PFAS see light as a breakdown or by-product of the production or combustion of other PFAS. Some ultra-short-chain PFAS can also be created by the action of UV rays on the new generation of coolants.
The major ultra-short-chain PFAS are TFA and PFPrA. “There is always a discussion among scientists about determining the toxicity of substances,” says Jacob De Boer. “A lot of importance is often attached to the element bio-accumulation: the extent to which a substance stores.”
“The problem with the ultra-short-chain PFAS is not so much that they accumulate in sediment or in fish, but that they are ‘water-loving’. If you use water that contains high concentrations of such substances, you have a problem. Unfortunately, bioaccumulation does not mean that the substances are not toxic.”
Drinkwater
Scientists look at drinking water with a frightened heart. A German study published last spring is appropriately titled: Ultra-Short-Chain PFASs in the Sources of German Drinking Water: Prevalent, Overlooked, Difficult to Remove, and Unregulated.
Of the PFAS found in German drinking water, no less than 98% was ultra-short-chain PFAS
The researchers took 46 samples from 13 locations where German drinking water is collected. Of the PFAS found in the samples, no less than 98% was ultra-short-chain PFAS. The concentrations of ultra-short-chain PFAS in (the tested) German drinking water are therefore many times higher than the concentrations of the better-known long- and short-chain PFAS.
During his research into the presence of PFAS in the Western Scheldt, Professor De Boer also examined a sample of Antwerp drinking water last spring. In doing so, he did not look for the ultra-short-chain PFAS. But the long- and short-chain PFAS were found in the sample at a concentration of 3.5 nanograms per liter (ng/l). That is hardly less than the maximum standard (4.4 ng/l) set by the Dutch National Institute for Health and Environment (RIVM) for drinking water.
Measurements of the concentrations of ultra-short-chain PFAS in Belgian drinking water are lacking, but based on the German results, they are in all probability much higher than the concentrations of other PFAS. And those villains are already pretty close to the maximum standard.
Blood
The German study not only points out that these ultra-short-chain PFAS are widespread, it also insists that the substances are completely ignored and barely regulated. “The ultra-short-chain PFAS pose a huge challenge for the production of drinking water. Preventive measures are necessary,” write the researchers in the scientific journal Environmental Science & Technology.
Drinking water comes into view as a source of high concentrations of ultra-short-chain PFAS in the blood
Even more worryingly, ultra-short-chain PFAS such as TFA and PFPrA are also found in high concentrations in human blood. There are few scientific studies on this. A Chinese study, the results of which were published in 2020 in the scientific journal Environment International, does set off alarm bells.
The researchers took samples from 252 test subjects. In their blood serum they found concentrations of TFA averaging 8.46 nanograms/milliliter (ng/ml). Concentrations of the more well-known PFAS such as PFOS and PFOA were found in the same samples of over 14 ng/ml. In comparison: the standard of the European Food Safety Authority EFSA for PFAS is 6.9 ng/ml. Residents near the 3M factory in Zwijndrecht have blood values that exceed the EFSA limit by up to 168 times.
The concentrations of ultra-short-chain PFAS in the blood are therefore lower than those of the longer PFAS. The fact that they are still so high is nevertheless disturbing. In contrast to PFOS and PFOA, ultra-short-chain PFAS have much less tendency to accumulate. They wash out much faster. The logical explanation for the fact that they are found in such high concentrations in the blood is that they are taken continuously. Drinking water contaminated with PFAS then comes into view as a source.
Great concern
Several other scientific studies investigate the distribution and occurrence of ultra-short-chain PFAS in the environment. For example, studies on the concentrations of TFA and PFPrA in rainwater in Japan. Or to the presence of the chemicals in a large lake in Sweden that functions as a local drinking water source.
All these studies express the same great concern about the impact on people and the environment. The plea to use the precautionary principle and also to quickly conduct additional research is recurring. The relatively limited data on the distribution as yet is sufficiently alarming. The substances have properties that suggest the worst.
Researchers who conducted another Swedish study on ultra-short-chain PFAS sum it up like this:
“Data on the toxicity of TFA and other ultra-short-chain PFAS are limited. More research is needed to map the potential hazards to humans and the environment (…) The fact that they are hardly biodegradable will lead to slightly increasing concentrations in the environment, especially in water and drinking water. Ultimately, people will be continuously exposed to elevated concentrations.”
Port of Antwerp as a PFAS hotspot
Flanders plays a crucial role in the whole story. The port of Antwerp is a hotspot for both the production (3M) and the breakdown (Indaver) of PFAS. As a by-product during production or as a residual product during combustion, the virtually non-degradable chemical waste ends up in the environment, via the air and via waste water.
As early as 2000, very high concentrations of ultra-short-chain PFAS were found on 3M’s sites
In all likelihood, very high doses are dumped into the environment in Antwerp. There is little direct data on this, but the data that do exist are alarming. In 2000, for example, very high concentrations of TFA and PFPrA were found on 3M’s sites. This is shown by an analysis of a groundwater screening, carried out in 2000 in the context of an exploratory soil study commissioned by the Public Flemish Waste company (OVAM).
The highest concentrations for PFPrA and TFA in 2000 were 7.1 and 9.4 mg/l, respectively. Remarkable: the concentrations found are not expressed in nanograms per liter like the EFSA standard, but in milligrams per litre. That is a factor of one million greater. This actually says everything about the measured concentrations.
“The soil remediation project from 2007 shows that PFPrA and TFA have indeed been detected several times,” says Thomas Goorden. “In many measurements it is even the largest fraction. Since then, however, those substances have disappeared from the measurements without a trace, partly because they are not included in the WAC (the list of official sampling methods, ToC). They are therefore not measured in any current research.”
Unfiltered
The high concentrations of ultra-short-chain PFAS are also not limited to 3M’s contaminated sites. Very high concentrations of PFPrA and TFA are also found in the rinse water from the chemical company.
Appendix 6 to the descriptive soil investigation by OVAM contains the composition of the so-called amine washing waters. In addition to high concentrations of PFOS and other longer-chain PFAS, this wash water also contains very high concentrations of TFA and PFPrA: 18.6 mg/l and 86.0 mg/l, respectively.
There is a very good chance that 3M has been discharging gigantic amounts of ultra-short-chain PFAS into the Scheldt for many years.
That washing water is purified, but research shows that the carbon filters purify long-chain PFAS, but are hardly effective for the ultra-short-chain PFAS. There is a very good chance that 3M has been discharging gigantic amounts of TFA and PFPrA into the Scheldt for many years.
“The molecules are simply too small for the carbon filters used at 3M,” says Thomas Goorden. “They already have a lot of trouble filtering short-chain PFAS such as PFBS and PFBA.”
At least implicitly, 3M admits that too. “In proceedings before the Council for License Disputes of March 22 this year, 3M indicated that it simply cannot filter these non-standard and unlicensed discharges,” says Goorden. The result is that the toxic products disappear in the Scheldt in unknown doses.
Indaver
In addition to 3M, there is also Indaver, which incinerates PFAS waste from 3M, but also from the factory of Chemours in Dordrecht, the Netherlands. The waste incinerator is committed to incinerating 99.9% of that PFAS waste. That statement may hold for PFOS and other long-chain PFAS, but not for short-chain PFAS such as PFBA and PFBS, let alone ultra-short-chain PFAS.
Jacob De Boer: ‘To also burn short-chain PFAS, you need a temperature of 1,500 °C. Indaver burns at 900 to 1,000 °C’
According to Jacob De Boer, the hypothesis that the combustion of long-chain PFAS produces a great deal of TFA and PFPrA as residual products is by no means far-fetched. “I recently spoke to an American colleague specialized in the matter at a conference. To also burn short-chain PFAS, you need a temperature of 1,500 °C. If you don’t, you end up with even shorter chains as residual products. These are then discharged through the water or emitted into the air. Indaver burns at 900 to 1,000 °C. That is not enough.”
The fact that in the application for a new environmental permit the company initially asked to continue discharging high concentrations of PFBA (initially 1,460 micrograms per litre) into the Scheldt seems to indicate that Indaver is aware of this problem.
TFA and PFPrA are neither mentioned in the environmental permit of 3M nor in that of Indaver. Whether that also means that there is no legal brake on the discharge of the chemical waste is unclear. What is certain is: as long as no government department measures which ultra-short-chain PFAS are being discharged, 3M and Indaver can continue to do their thing.
Apache contacted both 3M and Indaver. Both companies have not yet responded to our specific questions, but promised to answer.