Characterization of mono- to deca-chlorinated biphenyls in a well-preserved sediment core from Beppu Bay, Southwestern Japan: Historical profiles, emission sources, and inventory

Shin Takahashi; Hoang Quoc Anh; Isao Watanabe; Daichi Aono; Michinobu Kuwae; Tatsuya Kunisue

doi:10.1016/j.scitotenv.2020.140767

Characterization of mono- to deca-chlorinated biphenyls in a well-preserved sediment core from Beppu Bay, Southwestern Japan: Historical profiles, emission sources, and inventory

Sci Total Environ. 2020 Nov 15:743:140767. doi: 10.1016/j.scitotenv.2020.140767. Epub 2020 Jul 6.

Authors

Shin Takahashi¹, Hoang Quoc Anh², Isao Watanabe³, Daichi Aono³, Michinobu Kuwae⁴, Tatsuya Kunisue⁴

Affiliations

¹ Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address: takahashi.shin.mu@ehime-u.ac.jp.
² Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan; Faculty of Chemistry, University of Science, Vietnam National University, Hanoi, 19 Le Thanh Tong, Hanoi 10000, Viet Nam.
³ Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan.
⁴ Center for Marine Environmental Studies, Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan.

PMID: 32758843
DOI: 10.1016/j.scitotenv.2020.140767

Abstract

Contamination levels and profiles of mono- to deca-chlorinated biphenyls (PCBs) were characterized in a sediment core dated in 1954-2011 from Beppu Bay, southwestern Japan, providing a comprehensive and detailed picture on the environmental occurrence, temporal trends, and emission sources of these pollutants in the study area. Concentrations of total PCBs in the core ranged from 3.5 to 150 (median 15) ng g^-1 dry weight and exhibited depth profile matching with Japanese PCB production and emission patterns (i.e., drastically increasing from the early 1960s, peaking in 1970, and then rapidly decreasing). Origin of PCBs in the studied samples largely associated with Kanechlor mixtures (e.g., KC-300 and KC-400), especially for sediment layers dated between the mid-1960s and early 1970s (i.e., the intensive PCB production period in Japan). In addition, dechlorination and weathering signals and emerging inputs of PCBs were also observed in deeper and shallower sediment segments with notable proportions of some unique congeners such as CB-47/48/51 and CB-11, respectively. Historical fluxes of PCBs in our samples showed quite similar vertical shape as concentrations. In the context of national implementation for complete treatment of PCB-containing waste until 2024, further investigations on spatiotemporal trends and environmental loads of PCBs in Japan are necessary.

Keywords: Beppu Bay; Emission sources; Kanechlor; PCBs; Sediment core.