Long-chain perfluoro carboxylic acids in landfill leachate: Extraction, detection and biodegradation

Landfills serve as major repositories for products containing per- and polyfluoroalkyl substances (PFASs). These compounds have been documented in the resulting leachate, posing a significant threat to both surface water and groundwater quality. Long-chain perfluoro carboxylic acids (LC-PFCAs), which act as precursors to shorter-chain PFCAs, are particularly persistent in the environment. Despite this, data on LC-PFCA's occurrence in landfill leachate is limited, highlighting the need for thorough monitoring and control efforts. This study focuses on the extraction of LC-PFCA using solid-phase extraction (SPE), detection by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and their biodegradation using an autochthonous bacterial community of landfill leachate based on the hypothesis that native bacteria can consume these pollutants. The findings of the study indicate that SPE efficiency and PFCA recovery rates were higher in diluted leachate samples. LC-MS/MS exhibited superior sensitivity and accuracy compared to direct MS injection, with lower detection limits. Throughout the sampling period, perfluoro nonanoic acid (PFNA) and perfluoro decanoic acid (PFDA), were detected in concentrations ranging from 30 to 640 ng/L and 40-510 ng/L, respectively. Further, the native microbial community degraded spiked PFNA and PFDA (1, 10, and 100 mg/L), with efficiencies of 35.26 ± 5.47% and 53.38 ± 6.54%, respectively, and Aeromonas, Proteus, Moheibacter, Pseudochrobactrum, Providencia and Pseudomonas were identified as the most promising genus to degrade LC-PFCAs. Overall, these findings of the study highlight the significance of robust analytical methods for LC-PFCA detection and reveals the promising prospects for PFNA and PFDA biodegradation by pre-existing bacterial communities.