Heavier sediment pollution by per-and polyfluoroalkyl substances (PFASs) in tropical coasts compared to temperate regions: An overlooked hotspot
By Hui Xie, Shiya Gu, Yang Cui, Jianwei Dong, Hongbing Wang, and Guowei Fu
J. Environ. Sci.
June 14, 2025
DOI: 10.1016/j.jes.2025.06.021
Tropical coastal environments experience higher precipitation, more intense solar radiation, and elevated sea surface temperature compared to temperate regions. These environmental differences influence the behaviors and fate of per- and polyfluoroalkyl substances (PFASs), yet there is a critical gap in understanding the status of both legacy and emerging PFASs in tropical coastal sediments. This study provides a detailed analysis of the distribution, sources, and fate of legacy-, precursor, and emerging PFASs in coastal sediments around a tropical city. PFAS concentrations ranged from 1.33 to 12.6 ng/g, with five legacy PFASs (i.e., perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUnDA), perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), and perfluooctane sulfonate (PFOS)), and three precursors (i.e., 7H-perfluoroheptanoic acid (7H-PFHpA), 8H-perfluorooctanoic acid (8H-PFOA), and 9H-PFNA) consistently detected across all samples. Emerging alternatives, such as 6:2 chlorinated perfluoroether sulfonic acid, were also observed with detection frequencies of 20.0 %. Overall, PFAS concentrations in tropical coastal sediments obtained in this study were found to be higher than those reported in temperate regions. The identified main sources of PFASs include land-based inputs such as rainfall-runoff (48.7 %), emission from space launch base and dock activities (14.9 %), sediment resuspension-deposition (12.7 %), and atmospheric deposition (9.02 %). Additionally, certain sediment quality parameters acted as indicators for PFAS pollution. Total nitrogen and total phosphorus in sediments were potential indicators for those PFASs with sulfonyl groups, whereas sediment composition was strongly associated with monohydrogen-substituted perfluoroalkyl carboxylic acids and fluorotelomer (unsaturated) carboxylates. These findings provide new insights into the fate of PFASs in coastal environments and highlight the need for further research on their environmental impact.
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