Utility of bark chips for removal of fluorinatedorganic compounds in water samples at a hazardouswaste management facility

Abstract: Per- and polyfluoroalkyl substances (PFAS) are synthetic compounds that have beenaround since 1940. They can be used in a variety of products such as fire-fighting foam, food packaging and cosmetic products. Many PFAS have potential toxic effects on both humans and animals which poses a problem due to their wide distribution and persistency. Another problem concerns the remediation of PFAS, where the substances ends up circulating between the different disposal types (landfills, wastewater treatment and incineration). Active methods are therefore needed to remove or retain the contaminants. Some examples of these remediation technologies can be biomaterials, organoclays and more advanced methods such as activated carbon and ion exchange. The more advanced being suited for remediation of drinking water. In this study, the sorption efficiency of two pine bark fractions has been studied and also compared to the efficiency of activated carbon. The evaluation was done for both target analysis (PFAS-11) and non-specific analysis of extractable organofluorine (EOF) compounds in contaminated water from a hazardous waste management facility. The two pine bark fractions indicated similar sorption efficiencies, for both the PFAS-11 and the EOF compounds. The sorption efficiency ranged from 10% up to 75% for perfluorinated sulfonic acids (PFSA) and from below zero up to 40% for perfluorinated carboxylic acids (PFCA). A general pattern can be seen, the sorption efficiency increases with increasing length of the PFAS chain. The activated carbon had a higher sorption efficiency, where the majority of PFAS had an average sorption of 100%. In comparison, the PFAS-11 and total EOF analysis displayed high concentrations of unidentified EOF compounds. These compounds indicated a negative sorption, which might imply that non-targeted PFAS or other fluorinated organic compounds desorb from the bark. Therefore, the pine bark might be suitable as a rough remediation of long-chain PFAS (≥8C), but further studies on the sorption of unidentified fluorinated organic compounds are of interest.