Three different leaching approaches for the assessment of immobilization measures for PFASs in soils were compared and evaluated. For this purpose, TZW performed the trace analytical determinations by LC-MS/MS.
The large-scale soil contamination in the Rastatt/Baden-Baden area (approx. 1200 ha) with perfluorinated and polyfluorinated alkyl substances (PFASs) has a direct impact on various users, including the gravel industry, which has to remove and possibly dispose of the topsoil in order to extract gravel and sand. Among other things, the possibility of immobilising the PFASs in contaminated soils by adding special agents is being relied upon.
To prove the immobilisation effectiveness, methods are needed to demonstrate it experimentally. Therefore, different immobilisation approaches were investigated by experiments on three different scales (infinite sink experiments, column experiments, laboratory lysimeter) and under saturated and unsaturated conditions. The time course of PFAS concentrations in the experiments was measured and mathematically modeled by LC-MS/MS analysis and sum parameter analysis.
None of the methods investigated was able to answer all questions regarding leachability on its own. Long-term experiments indicated that degradation processes in soil lead to the long-term release of perfluorinated alkyl acids (PFAAs), which are currently difficult to predict.
Publications:
Bierbaum, T.; Klaas, N.; Haslauer, C.; Braun, J.; Lange, F. T.; Scheurer, M.: Entwicklung einer Methode zum Nachweis der PFAS-Immobilisierung. af-Info 2021, 9 (2021)
Bierbaum, T.; Klaas, N.; Haslauer, C.; Braun, J.; Lange, F. T.; Sacher, F.: Experimentelle Methoden zur Untersuchung der PFAS-Immobilisierung. Mitt. Umweltchem. Ökotox. 28, 83-87 (2022)
Link to article (in German)
