PFASs and their precursors and alternatives in seawater, sediment and bivalves from Korean coastal waters: Occurrence, spatial distribution and bioaccumulation potentials

Abstract

Per- and polyfluoroalkyl substances (PFASs) are a group of substances with at least one C-F molecular bonding. PFASs have been used for a variety of industrial applications, such as fluoropolymer, textiles, carpets, semiconductors, and firefighting foams since the first production and use of PFASs in the 1940s. Based on accumulated evidences of toxicities of longer-chained PFASs (PFOS and PFOA) have been identified in the 2000s, shorter-chained PFASs (e.g., PFBS and PFHxS) and some alternatives including [3H-perfluoro-3-[(3-methoxy-propoxy) propanoic acid] (ADONA) and hexafluoropropylene oxide dimer acid (HFPO-DA ammonium salt with trade name: GenX)] were introduced to industrial market. Despite this, limited data are available on PFASs in multiple environmental matrices from marine environment worldwide. In this study, seawater, sediment, and bivalves such as mussels and oysters were collected from 50 locations along the Korean coasts in 2018, to investigate occurrences, spatial distribution, and bioaccumulation potentials of perfluorinated compounds (PFCs) and their precursors and alternatives. Twenty-five PFASs including twelve perfluoroalkyl carboxylic acids (PFCAs), four perfluoroalkane sulfonic acids (PFSAs), six precursors and three alternatives were measured using a liquid chromatography coupled with a tandem mass spectrometry (LC-MS/MS) under the multiple reaction monitoring mode. Wide ranges of PFAS contamination and different contamination patterns of PFASs were found among environmental matrices based on physico-chemical properties of these contaminants. PFOA and PFOS were dominant in all environmental matrices, suggesting widespread contaminants in coastal environment. Short-chained PFASs were dominant in seawater samples, while longer-chained PFASs were dominant in sediment and bivalve samples. ADONA and GenX used for alternatives of PFOA were not detected in any samples, whereas F-53B used for an alternative of PFOS was detectable in some of sediment samples as low levels. Total concentrations of PFASs in seawater, sediment, and bivalves from Korean coasts ranged from 0.39 to 22.9 ng/L, 0.05 to 1.13 ng/g dry weight, and 1.55 to 25.7 ng/g dry weight, respectively. The highest concentrations of PFASs in seawater and sediment were observed in locations from highly industrialized coastal regions such as Asan and Gunsan, indicating potential sources of PFASs in coastal environment. The regional differences in compositional profiles of PFASs in seawater were observed but were not for sediment and bivalves. Significant correlations of PFASs were found within the same environmental matrices. PFOA and PFOS were significantly correlated between seawater and sediment or bivalves. To understand environmental behavior and a potential for bioaccumulation, partitioning coefficients (log Kd) and field-based bioaccumulation factors (BAFs) and biota-sediment accumulation factors (BASFs) were calculated for PFASs using multiple environmental samples. Values of log Kd between sediment and seawater ranged from 1.23 for PFHxS to 2.33 for PFOS. Log BAFs ranged from 0.60 for PFOA to 1.53 for PFOS and BSAF increased with an increasing number of chain length of PFASs (−2.46 for PFOA to −1.07 for PFTeDA). As the results of this study, PFASs including precursors and alternatives are ubiquitous environmental contaminants in coastal waters of Korea as evidenced by their occurrences and detectable levels. Further studies are needed to understand environmental fate and adverse health risks of PFCs and their precursors and alternatives (e.g., F-53B) through intensive survey on highly contaminated regions.