Occurrence, distribution, and fate of polychlorinated biphenyls (PCBs) in multiple coral reef regions from the South China Sea: A case study in spring-summer

• Published in: The Science of the total environment Vol. 777; p. 146106
• Main Authors: Zhang, Ruijie, Kang, Yaru, Yu, Kefu, Han, Minwei, Wang, Yinghui, Huang, Xueyong, Ding, Yang, Wang, Ruixuan, Pei, Jiying
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.07.2021
• Subjects: Atmospheric deposition; Bioaccumulation; Coral tissue; Polychlorinated biphenyls (PCBs); South China Sea; South China Sea; Atmospheric deposition; Coral tissue; Bioaccumulation; Polychlorinated biphenyls (PCBs)
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.146106

Concentrations of 24 PCBs were simultaneously determined in air, seawater, and corals from the South China Sea (SCS) in spring-summer for understanding their distribution and fate in multiple coral reef regions. The ∑24PCBs (6.8–294 pg m−3) were mainly influenced by air mass origins in air samples. Southeast monsoon caused higher ∑24PCBs (mean: 61 pg m−3) than the southwest (mean: 19 pg m−3). ∑24PCBs in seawater (2.8–7.7 pg L−1) was equally distributed from the nearshore to offshore regions under low flow velocity and swirling state of the ocean current. Significantly higher air-water gas exchange deposition fluxes (3.5–29 ng m−2 d−1) than dry deposition (0.14–2.0 ng m−2 d−1) indicated that diffusion of PCBs from the atmosphere into seawater was the governing process in the SCS. PCBs in corals are strong bioaccumulative (Log BAFs: 2.49–7.86). The distribution of ∑24PCBs in coral tissues (nd – 42.9 ng g−1 dw) was significantly correlated with that in air samples, suggesting PCBs may have a migration pattern of atmosphere-ocean-corals in the SCS. Compared to a previous risk assessment study, the ∑24PCBs in corals from the SCS may cause potential risks to corals by reducing zooxanthellae density, chlorophyll-a (Chl-a) and chlorophyll-C2 (ChlC2) in corals. [Display omitted] •First report of PCBs in coral reef regions from multiple coastal and offshore regions•Ocean currents and monsoons played essential roles in spatial distribution of PCBs.•PCBs concentrations in coral reef regions were at the lower end of the global range.•PCBs' net deposition occurred in air-water exchange process in the South China Sea.•PCBs may have a migration pattern of atmosphere-ocean-corals in the South China Sea.