title: Divergence of stable isotopes in tap water across China.
abstract: Stable isotopes in water (e.g., δ2H and δ18O) are important indicators of hydrological and ecological patterns and processes. Tap water can reflect integrated features of regional hydrological processes and human activities. China is a large country with significant meteorological and geographical variations. This report presents the first national-scale survey of Stable Isotopes in Tap Water (SITW) across China. 780 tap water samples have been collected from 95 cities across China from December 2014 to December 2015. (1) Results yielded the Tap Water Line in China is δ2H = 7.72 δ18O + 6.57 (r2= 0.95). (2) SITW spatial distribution presents typical "continental effect". (3) SITW seasonal variations indicate clearly regional patterns but no trends at the national level. (4) SITW can be correlated in some parts with geographic or meteorological factors. This work presents the first SITW map in China, which sets up a benchmark for further stable isotopes research across China. This is a critical step toward monitoring and investigating water resources in climate-sensitive regions, so the human-hydrological system. These findings could be used in the future to establish water management strategies at a national or regional scale.
authors.affiliation: Department of Hydraulic Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Sihan
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Hydraulic Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Hongchang
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Hydraulic Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Tian
authors.affiliation: Department of Hydraulic Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Tie
authors.affiliation: Indiana University-Purdue University Indianapolis, 723 W Michigan St, SL 118M, IN 46202, USA.
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Pacific Northwest National Laboratory, Joint Global Change Research Institute 5825 University Research Ct, MD 20740, USA.
authors.forename: Yaling
authors.initials: Y
authors.lastname: Liu
authors.affiliation: National Meteorological Information Center, Beijing 10081, P. R. China.
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Shi