Spatial distribution characteristics of perfluoroalkyl substances in bulk and grain size fractionated sediments in Shenzhen Bay

Understanding Perfluoroalkyl substances (PFASs) spatial distribution in natural environments is crucial due to their environmental persistence and potential bioaccumulation. However, limited research has investigated PFASs spatial distribution at a high resolution, especially in the Guangdong -Hong Kong -Macao Greater Bay Area. Here, we examined the composition and concentration of PFASs in 36 bulk surface sediments and grain -size fractionated sediments from 9 representative sites to determine the spatial distribution characteristics in Shenzhen Bay. We found that sigma PFASs decreased gradually from nearshore area to offshore area (0.680 and 0.297 ng g-1 dw, respectively). Furthermore, PFASs are easily adsorbed on fine-grained sediments, likely due to their chain length and hydrophobicity. We argue that the lateral movement of sediments may transport finegrained sediments associated with sigma PFASs out of the bay, resulting in the spatial difference in sigma PFASs in Shenzhen Bay. Our findings provide important insights into explore the mechanisms associated with preservation and transport of PFASs.