Detection of per- and polyfluoroalkyl substances in biosolids from wastewater treatment plants

Per- and polyfluoroalkyl substances (PFASs), with unique and special surfactant activities and chemical properties, are widely used in a variety of industrial and consumer products. The worldwide distribution and ubiquitous presence of these substances has aroused research interests and concerns all over the world. Wastewater treatment plants (WWTPs) have been considered as an important precipitates and sources of PFASs compounds in the environment. In this study, a method was developed to detect PFASs in biosolids using high-performance liquid chromatography (HPLC) system coupled with high-resolution mass spectrometer (HRMS). A solid phase extraction (SPE) procedure was applied to extract the PFAS analytes from biosolid samples collected from two local wastewater treatment plants (WWTPs). The SPE procedure under basic conditions showed effective extraction for ionic analytes, with recoveries of 85.62 % and 114.65 % for PFOA and PFOS, respectively. The acidic SPE extraction showed relatively low recoveries for zwitterionic and ionic analytes. Totally 30 analytes were detected in two biosolid samples. PFOS were the predominant PFASs, with concentrations from 27.04 ng/g to 73.03 ng/g dry weight