Geoprobe soil sample equipment
The newly developed methods mean a breakthrough that takes the analysis of PFAS in soil to the next level and also reveals the presence of the PFAS-precursors and new chemicals that is said to be degradable.

New analysis methods reveal un-explored PFAS-chemicals in the soil

Two new analysis methods has been developed to reveal un-explored PFAS-chemicals in the soil in a unique co-operation between NIRAS, Örebro University and the laboratory Eurofins.

27. Aug 2018

The two new analysis methods to reveal per- and polyfluoralkyl substances (PFAS) in the soil show that actions made so far is probably not enough. Areas of land that up to now have been assessed as unaffected may well have, or in the future get, high levels of PFAS and will thereby receive another classification.

The contaminants of the persistent highly fluorinated substances that is spread on land and in the ground water has got the society’s interest more and more in recent years. The chemicals can lead to infertility or cancer or affect the immune system of both humans and animals. PFAS are often used to obtain water, dirt and fat repelling surfaces, and are used in a large number of everyday products such as e.g. in rain clothes, shoes, electronics, teflon pans and firefighting agents.

Despite the knowledge of the chemicals’ dangerous attributes it is only one substance, perfluorooctane sulfonate (PFOS), that is prohibited and a few that is regulated. Hence the suppliers of the chemicals develop new highly fluorinated substances  that is marketed as degradable they still have the same qualities as their precursors. In this context degradable only means that the chemicals can be transformed into one of the regulated PFAS substances. The consumers are fooled into believing that the problem is solved and that they are using good products. The product can still in fact be just as dangerous even if it can take time before the chemicals are transformed into any of the regulated PFAS substances. 

Better analysis results with the new methods

To investigate the levels of PFAS contaminants in the soil it has up until now been possible to analyse the presence and levels of the 20-30 most common and regulated substances. But to only analyse about twenty PFAS chemicals most likely give an incomplete result of the presence of contaminants in the soil since more than 4730 different PFAS chemicals are being used on the market according to OECD. To be able to give a fair result the levels of so far unexplored PFAS chemicals need to be revealed too.

Many of the about twenty PFAS substances that so far have been analyzed are not used in the new products and a soil sample may therefore seem unpolluted when analysed. The newly developed methods mean a breakthrough that takes the analysis of PFAS in soil to the next level and also reveals the presence of the PFAS-precursors and new chemicals that is said to be degradable.

“To give false positive assessments of contaminated soil may become a future problem if environment consultants assume a site to be free of PFAS when it in fact is not”, says Mark Filipovic, PFAS specialist.

With help of total oxidizable precursor (TOP-assay) the PFAS-precursors and new chemicals can transform to any of the 20-30 substances that is measurable. Since some of the PFAS substances may still be intact or resistant to TOP-assay an identical sample is being parallel analysed with total extractable organic fluorine (EOF-analysis). This analysis make the total amount of fluorine ions derived from organic substances visible. These substances are calculated and then reveals the total level of PFAS in the sample. By using the TOP and EOF analysis a far more accurate result can be given even if all 4730 different PFAS chemicals cannot be detected.

Together with great experience and the innovative tools we have developed ourselves we can give our customers better knowledge about the presence of PFAS substances. This way better risk assessments can be made and thus provide a stronger basis when choosing suitable remedial actions.

“All problems becomes smaller when you confront them instead of ignoring them,” says Marko Filipovic and continues: “This is in line with NIRAS’ core values – we listen, we learn and we deliver.”

The analysis methods will be presented on the international conferences DioXin 26-31 August in Krakow, Poland and NORDROCS 3-5 September in Helsingör, Denmark.

Read more detailed information about the methods here.