Oral Presentation SETAC Asia-Pacific Virtual Conference 2022

Tissue-Specific Uptake, Depuration Kinetics, and Suspected Metabolites of Three Emerging Per- and Polyfluoroalkyl Substances (PFASs) in Marine Medaka (#46)

QI WANG 1 2 3 , Yuefei Ruan 1 2 3 , Linjie Jin 1 2 , Huiju Lin 1 , Meng Yan 1 3 , Jiarui Gu 1 , Calista Yuen 1 , Kenneth Leung 1 , Paul Lam 1 2 3 4
  1. State key laboratory of marine pollution, City University of Hong Kong, Hong Kong, Kowloon
  2. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong, Kowloon
  3. Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Hong Kong, Kowloon
  4. Hong Kong Metropolitan University, Hong Kong

Restrictions on legacy per- and polyfluoroalkyl substances (PFASs) have led to the widespread use of emerging PFASs. However, their toxicokinetics have rarely been reported. Here, tissue-specific uptake and depuration kinetics of perfluoroethylcyclohexanesulfonate (PFECHS) and 6:2 and 8:2 chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs) were studied in marine medaka (Oryzias melastigma). The fish were exposed to these substances for 28 days (0.2 μg/L), followed by a clearance period of 14 days. The depuration constant (kd) of PFECHS [0.103 ± 0.009 day–1 (mean ± standard deviation)] was reported for the first time. Among the six studied tissues, the highest concentrations of 6:2 Cl-PFESA, 8:2 Cl-PFESA, and PFECHS were found in the liver [1540, 1230, and 188 ng (g of wet weight)−1, respectively] on day 28 while the longest residence times were found in the eyes (t1/2 values of 21.7 ± 4.3, 23.9 ± 1.5, and 17.3 ± 0.8 days, respectively). No significant positive correlation was found between the bioconcentration factors of the studied PFASs and the phospholipid or protein contents in different tissues of the studied fish. Potential metabolites of Cl-PFESAs, i.e., their hydrogen-substituted analogues (H-PFESAs), were identified by time-of-flight mass spectrometry. However, the biotransformation rates were low (<0.19%), indicating the poor capacity of marine medaka to metabolize Cl-PFESAs to H-PFESAs.