Hydrochemical characteristics of underground fluid observation wells in Shandong Liyuan Wen, Zhen Jia, Zongbin Guo, Kaixuan Lian, Bingdun Yan, Yi Cao and Qifeng Chen E3S Web Conf., 520 (2024) 01010 Published online: 03 May 2024 DOI: 10.1051/e3sconf/202452001010