Spatial distributions, behaviors, and sources of PCDD/Fs in surface water and sediment from the Yangtze River Delta

Rongrong Lei; Wenbin Liu; Yunchen He; Tianqi Jia; Changliang Li; Wei Su; Yi Xing

doi:10.1016/j.envres.2024.118540

Spatial distributions, behaviors, and sources of PCDD/Fs in surface water and sediment from the Yangtze River Delta

Environ Res. 2024 Feb 23;251(Pt 1):118540. doi: 10.1016/j.envres.2024.118540. Online ahead of print.

Authors

Rongrong Lei¹, Wenbin Liu², Yunchen He³, Tianqi Jia³, Changliang Li⁴, Wei Su⁵, Yi Xing¹

Affiliations

¹ School of Energy and Environmental Engineering, The University of Science and Technology Beijing, Beijing, 100083, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China; Research Center for Eco-Environmental Sciences, Beijing, 100085, China; Hangzhou Institute for Advanced Study, UCAS, Hangzhou, 310024, China. Electronic address: wbliu@ucas.ac.cn.
³ College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 101408, China; Research Center for Eco-Environmental Sciences, Beijing, 100085, China.
⁴ Research Center for Eco-Environmental Sciences, Beijing, 100085, China.
⁵ School of Energy and Environmental Engineering, The University of Science and Technology Beijing, Beijing, 100083, China. Electronic address: suwei@ustb.edu.cn.

PMID: 38401685
DOI: 10.1016/j.envres.2024.118540

Abstract

The Yangtze River Delta (YRD), one of the most economically developed and industrialized regions in China, is confronted with challenges arising from rapid urbanization, particularly environmental pollution. The collection of surface water and sediment samples from forty-nine sites in the YRD was conducted to analyze 2378-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) congeners. The detected concentrations of PCDD/Fs were 0-5.3 pg TEQ/L in water and 0.12-1493 pg TEQ/g dw in sediment. The PCDD/Fs contamination in the sediment was widespread in the YRD. There were variations in the congener characteristics of PCDD/Fs in surface water and sediment. The proportion of OCDD was significantly lower in surface water samples compared to sediment, while the less chlorine-substituted homologs were found in larger proportions. To understand the partitioning and behavior of dioxins within the water-sediment system, we calculated the organic carbon normalized partition coefficients and fugacity fraction (ff) of PCDD/F congeners. The results revealed that the PCDD/Fs had not attained a state of distributional equilibrium, and the non-specific hydrophobic effect seemed minimally influential on their partitioning between sediment and water. The average ff values, which varied between 0.06 and 0.63, indicated differing migration directions for the PCDD/F congeners. Source identification analysis provided evidence that the dioxins in the river water were primarily attributed to industrial thermal processes. Iron and steel smelting, along with pesticide production and use, were likely responsible for the sediment contamination. This comprehensive analysis underscores the complex nature of PCDD/Fs pollution in the YRD and highlights the necessity for targeted environmental management strategies.

Keywords: Congener pattern; PCDD/F; Potential sources; Spatial distribution; Transfer and fate.