Spatiotemporal variability of groundwater chemistry, source identification and health risks in the southern Chinese Loess Plateau

Zijun Li; Qingchun Yang; Chuan Xie; Hongyun Ma; Bin Wu; Yanli Wang

doi:10.1016/j.ecoenv.2024.117429

Spatiotemporal variability of groundwater chemistry, source identification and health risks in the southern Chinese Loess Plateau

Ecotoxicol Environ Saf. 2024 Dec 1:289:117429. doi: 10.1016/j.ecoenv.2024.117429. Online ahead of print.

Authors

Zijun Li¹, Qingchun Yang², Chuan Xie³, Hongyun Ma⁴, Bin Wu⁵, Yanli Wang⁶

Affiliations

¹ School of Geographical Sciences, Hebei Normal University, Shijiazhuang 050024, China; Hebei Key Laboratory of Environment Change and Ecological Construction, Hebei Normal University, Shijiazhuang 050024, China; Hebei Technology Innovation Center for Remote Sensing Identification of Environmental Change Hebei Normal University, Shijiazhuang 050024, China.
² Key Laboratory of Groundwater Resources and Environment Ministry of Education, Jilin University, Changchun 130021, China. Electronic address: qyang@jlu.edu.cn.
³ Geothermal Institute, Hebei Hydrological Engineering Geology Survey, Shijiazhuang 050000, China.
⁴ Key Laboratory for Groundwater and Ecology in Arid and Semi-arid Areas, Xi'an Center of Geological Survey, CGS, Xi'an 710054, China.
⁵ Technical Centre for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing 100012, PR China. Electronic address: wubin@tcare-mee.cn.
⁶ Limited Company of Beijing Satellite Manufacturing Factory, Beijing 100094, PR China.

PMID: 39622128
DOI: 10.1016/j.ecoenv.2024.117429

Abstract

Groundwater pollution of the loess plateau regions has become a global concern due to its vulnerability to natural and anthropogenic influences. In this study, 146 water samples were investigated to identify the spatiotemporal variability in groundwater chemistry, pollution sources and nitrate health risks in two interconnected river basins of a typical loess region. The results showed that except for bicarbonate, spatiotemporal variability of hydrochemical components in Malian River Basin (ML) was generally greater than that in Upper Jinghe River basin (JH-U) due to the hydrogeological conditions, and the hydrochemical facies in two river basins transformed from SO₄·Cl and Cl·SO₄ types to HCO₃ and HCO₃·SO₄ types. The results of integrated-weight quality index (IWQI) showed that 77.8 % (1970s), 33.3 % (2004), 34.3 % (2015) of samples in ML exceeded the standard limits of Class IV groundwater quality, displaying a high pollution level with an improvement trend, while groundwater quality in JH-U indicated a very low pollution level with a deterioration trend. The geogenic source was identified as a main factor affecting groundwater quality, with contributions of 59.2 % and 48.7 % in JH-U and ML (2015), respectively. The anthropogenic sources including agricultural activities (20.7 % and 21.8 % in JH-U and ML) and coal mining activities (20.1 % and 29.5 % in JH-U and ML) also played a role in affecting groundwater quality. The nitrate health risk assessment demonstrated that 39.1 % and 20.3 % of groundwater samples (2015) significantly exceeded the standard threshold (Hazard Index = 1), implying a higher health risk to children than adults, and the nitrate health risk in ML was obviously greater than that in JH-U. This study provides novel insight into the spatiotemporal variability in groundwater chemistry, quality and health risk in loess regions under the influence of geogenic and anthropogenic factors.

Keywords: Groundwater chemistry; Nitrate health risk assessment; Source identification; Spatiotemporal variability; Stable isotope analysis.