Occurrence and prevalence of per- and polyfluoroalkyl substances in the sediment pore water of mariculture sites: novel findings of PFASs from the Bohai and Yellow Seas using a newly established analytical method

A new method for the determination of 26 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in marine sediment pore water was developed using online solid phase extraction coupled with liquid chromatography-tandem mass spectrometry. The proposed method requires only about 1 mL of pore water samples. Satisfactory recoveries of most target PFASs (83.55%–125.30%) were achieved, with good precision (RSD of 1.09%–16.53%), linearity (R2≥0.990), and sensitivity (MDLs: 0.05 ng/L–5.00 ng/L for most PFASs). Subsequently, the method was applied to determine PFASs in the sediment pore water of five mariculture bays in the Bohai and Yellow Seas of China for the first time. Fifteen PFASs were detected with total concentrations ranging from 150.23 ng/L to 1838.48 ng/L (mean=636.80 ng/L). The ∑PFASs and PFOA concentrations in sediment pore water were remarkably higher than those in surface seawater (tens of ng/L), indicating that the potential toxic effect of PFASs on benthic organisms may be underestimated. PFPeA was mainly distributed in pore water, and the partition of PFHpA (50.99%) and PFOA (49.01%) was almost equal in the solid and liquid phases. The proportions of all other PFASs partitioned in marine sediments were significantly higher than those in pore water. A new method for the determination of legacy and emerging PFASs in marine sediment pore water was developed, and only 1 mL of samples is necessary to meet the requirements for the determination of 26 PFASs in actual pore water samples. This method facilitates investigations on PFASs in pore water of marine sediment, which will help clarify the occurrence, pollution level, and partitioning behaviors of PFASs in the benthic environment of mariculture zones. Moreover, high concentrations of PFASs were detected in the pore water of five mariculture bays in China for the first time. These results will attract scholars to pay attention to and study the PFASs in the benthic environment of mariculture areas.