The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

832 / 2024-09-19 15:47:39

Effect of front on polycyclic aromatic hydrocarbons temporal-spatial variations and water-particle partitioning in the South China Sea

polycyclic aromatic hydrocarbons（PAHs), particle-water partitioning, Ocean fronts, South China Sea

Oceanic processes such as fronts, could influence the spatial-temporal distribution and environmental behaviors of semi-volatile organic pollutants, such as Polycyclic aromatic hydrocarbons (PAHs), in marine environment, but our understanding of its effect on PAHs dynamics remains limited. This study used field observations to investigate front in the South China Sea; and its potential effect on the spatial and diurnal variations of PAHs distribution and transport. Seawater samples were collected from surface water and water columns in the front zone from the South China Sea. The range of dissolved phase PAHs (DPAHs) was 35.68–753.47 ng/L, while the range of particle phase PAHs (PPAHs) was 0.13–5.34 ng/L. Results of isomeric ratios and PMF analysis illustrated DPAHs mainly originated from petroleum source, and PPAHs derived from pyrolytic source. Notably, a significant positive correlation was observed between the octanol-water partition coefficient (K_ow) and Water-partitioning coefficient (K_d) of 3-4 ring. The study of cross-frontal PAHs transport revealed that front has an effect on scavenging PAHs.The observational evidences shown in this study provide important information for further understanding the POPs water-particle partitioning effects associated with the front processes in the marginal sea.