Acesulfame as a suitable sewer tracer on groundwater pollution: A case study before and after the 2016 Mw 7.0 Kumamoto earthquakes

Eri Ishii; Yuta Watanabe; Tetsuro Agusa; Takahiro Hosono; Haruhiko Nakata

doi:10.1016/j.scitotenv.2020.142409

Acesulfame as a suitable sewer tracer on groundwater pollution: A case study before and after the 2016 M_w 7.0 Kumamoto earthquakes

Sci Total Environ. 2021 Feb 1:754:142409. doi: 10.1016/j.scitotenv.2020.142409. Epub 2020 Sep 18.

Authors

Eri Ishii¹, Yuta Watanabe¹, Tetsuro Agusa², Takahiro Hosono³, Haruhiko Nakata⁴

Affiliations

¹ Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
² Faculty of Environmental and Symbiotic Science, Prefectural University of Kumamoto, 3-1-100, Tsukide, Higashi-ku, Kumamoto 862-8502, Japan.
³ Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
⁴ Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan. Electronic address: nakatah@kumamoto-u.ac.jp.

PMID: 33254947
DOI: 10.1016/j.scitotenv.2020.142409

Abstract

On April 14th and 16th, 2016, two large-scale earthquakes (M_w 6.2 and 7.0) occurred in Kumamoto, Japan. The sewer system was seriously damaged and there were concerns about groundwater pollution by sewer exfiltration. In this study, artificial sweeteners including acesulfame (ACE) in groundwater were analyzed before and after the earthquakes to evaluate sewage pollution and its temporal variation. Before the earthquakes, ACE was detected in 31 of 49 groundwater samples analyzed, indicating that wastewater may have leaked into groundwater. Groundwater was sampled from the same locations 2, 7, 12, and 30 months after the earthquakes. The detection frequency and median concentration of ACE in groundwater increased significantly 7 months after the earthquakes, from several tens to maximumly 189 times greater than the pre-earthquake concentrations. This suggests the earthquakes caused serious damage to sewer pipes and groundwater may be polluted. However, ACE concentrations drastically decreased or remained low 30 months after the earthquakes, probably due to the recovery and restoration work of sewer infrastructure. This study shows that ACE is an excellent tracer for evaluating sewer exfiltration to groundwater. In addition, it is important to obtain data on sewage tracers under normal condition as part of preparations for large-scale earthquakes.

Keywords: Acesulfame; Groundwater pollution; Large-scale earthquake; Sewer tracer.