Sediment samples from 25 locations in the Pensacola Bay System (PBS) watershed were analyzed for the presence of 51 per- and polyfluoroalkyl substances (PFAS) using ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and selected reaction monitoring. Results revealed quantifiable concentrations of PFAS in all sampling locations. More specifically, perfluorobutanoic acid (PFBA) was present in every sediment sample with a minimum and maximum concentration of 0.04 to 0.48 ng g-1 dry weight, respectively, across the 25 sites with an average of 0.1 ± 0.09 ng g-1. While PFOS, with an average of 0.11 ± 0.14 ng g-1 (range: <LOQ - 0.52 ng g-1) was the most abundant by concentration. LOQ of PFBA and PFOS were 0.01 ng g-1 and 0.1 ng g-1, respectively. PBS 22 site had the highest concentration of total (ΣPFAS) PFAS with 3.89 ng g-1 and the third highest number of PFAS were detected in this location (23 out of 51 PFAS monitored). These results could be due to the proximity of this site to a paper manufacturing company. Site PBS 21, which is close to the Pensacola International Airport (PNS), had the second highest concentration of PFAS with 1.68 ng g-1. Comparison between the ΣPFAS concentration present in sediments collected in July 2020 and sediments collected from nine repeat sites after Hurricane Sally (HS, September 2020), showed values, on average, 47% lower. These results highlight that the PBS area require further environmental monitoring and management of PFAS.
Keywords: Pensacola Bay System; Per-and polyfluoroalkyl substances (PFAS); Sediment; Storm events; UHPLC-MS/MS.