Hydrochemical characteristics and groundwater quality in the thick loess deposits of China

Springer Science and Business Media LLC - Tập 29 - Trang 8831-8850 - 2021
Shujian Li1, He Su2, Zhi Li1
1College of Natural Resources and Environment, Northwest A&F University, Yangling, China
2College of Mining Engineering, Taiyuan University of Technology, Taiyuan, China

Tóm tắt

Water quality and quantity should be paid more attention in regions with arid climate and thick vadose zones since the limited groundwater cannot be replenished rapidly once polluted. This study focused on the Loess Plateau of China to investigate the geochemical mechanism affecting groundwater chemistry and to calculate contribution rates of multiple sources to groundwater solutes. We employed multiple methods (diagrams, bivariate analyses, hierarchical cluster analysis (HCA), sodium adsorption ratio (SAR), water quality index (WQI), correlation analysis, and forward model) for the above purposes. We collected 64 groundwater samples in the thick loess deposits in June 2018 (flood season) and April 2019 (dry season). The average concentrations of cation were in the order of Ca2+ > Na+ > Mg2+ > K+ in the flood season, and Na+ > Ca2+ > Mg2+ > K+ in the dry season. The order of anions contents in the flood season and the dry season were HCO3- > SO42- > Cl- > NO3-. The major hydrochemical facies were Ca-HCO3 and Ca·Mg-HCO3 in the flood season and Na·Ca-HCO3·SO4 and Na-HCO3 in the dry season, respectively. Most of the groundwater (95% in the flood season and 96% in the dry season) was suitable for drinking, and the overall water quality was acceptable for irrigation. Mineral dissolution and cation exchange were important natural processes affecting groundwater chemistry. The forward model showed that the contribution of atmospheric input, anthropogenic input, evaporite dissolution, silicate weathering, and carbonate weathering to solutes in groundwater was 2.3±1.5%, 5.0±7.1%, 19.3±21.4%, 42.8±27.3%, and 30.6±27.1% in the flood season, and 9.1±6.4%, 3.4±5.2%, 20.3±15.9, 56.6±23.2%, and 10.7±15.4% in the dry season, respectively. Obviously, silicate and carbonate weathering contribute the most to groundwater chemistry in the flood season, while silicate weathering and evaporite dissolution contribute the most in the dry season. Although the overall contribution of anthropogenic inputs was insignificant, it was the dominant source of solutes for local groundwater. This study provides fundamental information for water management in arid areas.

Tài liệu tham khảo

Brindha K, Rajesh R, Murugan R, Elango L (2011) Fluoride contamination in groundwater in parts of Nalgonda District, Andhra Pradesh, India. Environ Monit Assess 172:481–492

EANET (2018) Wet Monthly 2018. Network Center for EANET. https://monitoring.eanet.asia/document/public/index. Accessed 18 July 2021

EANET (2019) Wet Monthly 2019. Network Center for EANET. https://monitoring.eanet.asia/document/public/index. Accessed 18 July 2021

Green CT, Liao L, Nolan BT, Juckem PF, Shope CL, Tesoriero AJ, Jurgens BC (2018) Regional variability of nitrate fluxes in the unsaturated zone and groundwater, Wisconsin, USA. Water Resour Res 2018(54):301–322

Li P, He X, Li Y, Xiang G (2019a) Occurrence and health implication of fluoride in groundwater of loess aquifer in the Chinese loess plateau: a case study of Tongchuan, Northwest China. Expo Health 11:95–107

Schoeller H (1967) Hydrodynamique dans le karst. Chron Hydrogéol 10:7–21

Su YH, Feng Q, Zhu GF, Si JH, Zhang YW (2007) Identification and evolution of groundwater chemistry in the Ejin Sub-Basin of the Heihe River, Northwest China. Pedosphere 17:331–342

Wilcox LV (1955) Classification and use of irrigation waters. USDA, Washington