Can water dating trace the transport history of HCHs in the ocean?

Weimin Wang; Haowen Zheng; Peng Huang; Jiandong Ye; Mengyang Liu; Yan Lin; Yifan Li; Mian Chen; Hongwei Ke; Minggang Cai

doi:10.1016/j.scitotenv.2023.166227

Can water dating trace the transport history of HCHs in the ocean?

Sci Total Environ. 2023 Dec 10:903:166227. doi: 10.1016/j.scitotenv.2023.166227. Epub 2023 Aug 11.

Authors

Weimin Wang¹, Haowen Zheng², Peng Huang³, Jiandong Ye², Mengyang Liu⁴, Yan Lin⁵, Yifan Li⁶, Mian Chen², Hongwei Ke², Minggang Cai⁷

Affiliations

¹ School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China; Zhejiang Institute of Tianjin University, Ningbo 315000, China.
² College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
³ College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China.
⁴ State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, 999077, China.
⁵ School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen 361024, China.
⁶ School of Environment, Harbin Institute of Technology, Harbin 150090, China.
⁷ College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China. Electronic address: mgcai@xmu.edu.cn.

PMID: 37574073
DOI: 10.1016/j.scitotenv.2023.166227

Abstract

Long-range atmospheric and oceanic transport play a crucial role in the accumulation of persistent organic pollutants (POPs), including hexachlorocyclohexanes (HCHs), in the Arctic Ocean. Herein, transient tracers, specifically chlorofluorocarbon-12 and sulfur hexafluoride, were used to determine the ventilation time of HCHs. Results revealed that dissolved HCHs can penetrate to a depth of ~500 m in the western Arctic Ocean, corresponding to water masses with a mean age of 45 ± 14 years. The average long-range transport time for α-HCH from initial atmospheric release to entering the western Arctic Ocean was estimated to be >30 ± 5 years, indicating continued moderate to high ecological risks from HCHs in the Arctic. This study demonstrates that transient tracers serve as effective water dating tools to elucidate the transport history of stable POPs in the ocean, contributing to a better understanding of their environmental characteristics and fate.

Keywords: Arctic; Hexachlorocyclohexanes; Long-range transport; Tracers; Ventilation.