Hydrochemical evolution characteristics, controlling factors, and high nitrate hazards of shallow groundwater in a typical agricultural area of Nansi Lake Basin, North China

Shou Wang; Jing Chen; Shuxuan Zhang; Xiaoyan Zhang; Dan Chen; Jiao Zhou

doi:10.1016/j.envres.2023.115430

Hydrochemical evolution characteristics, controlling factors, and high nitrate hazards of shallow groundwater in a typical agricultural area of Nansi Lake Basin, North China

Environ Res. 2023 Apr 15:223:115430. doi: 10.1016/j.envres.2023.115430. Epub 2023 Feb 7.

Authors

Shou Wang¹, Jing Chen², Shuxuan Zhang¹, Xiaoyan Zhang¹, Dan Chen¹, Jiao Zhou¹

Affiliations

¹ College of Agricultural Science and Engineering, Hohai University, No.8 Focheng West Road, Nanjing, Jiangsu, 211100, China.
² College of Agricultural Science and Engineering, Hohai University, No.8 Focheng West Road, Nanjing, Jiangsu, 211100, China. Electronic address: chinsei@163.com.

PMID: 36754107
DOI: 10.1016/j.envres.2023.115430

Abstract

Anthropogenic nitrate contamination in groundwater could not be neglected, which has been a global issue threatening public health, especially in agricultural fields where fertilizers were used intensively. The present study focused on evaluating the groundwater evolution process, quality, and associated health risks from nitrate pollution in Nansi Lake Basin (NLB), a typical intensive agricultural region of North China. For this purpose, fifty-two shallow groundwater samples were collected and analyzed major chemical parameters in June 2022. The groundwater samples are found to be mainly dominated by HCO₃-Ca·Mg and SO₄·Cl-Ca·Mg types. Water-rock interactions like minerals dissolution/precipitation and ion exchange were found to be the important processes influencing hydrochemistry. Nitrate content in groundwater fluctuated from 1.9 to 750.0 mg/L (average:148.7 mg/L), with about 75% of samples surprisingly exceeding the permissible limit (50 mg/L) set by the World Health Organization (WHO). Anthropogenic activities can be classified as excessive nitrogen fertilizer application, livestock manure, and industrial/domestic sewage, coupled with irrigation return flow, which brought significant hazards to human health. The calculation results of entropy weighted water quality index (EWQI) showed that about half of groundwater samples are unfit for drinking purposes. Most importantly, 88.5%, 88.5%, 73.1%, and 71.2% of the water samples had considerable NO₃^- health risks (HQ > 1) for infants, children, females, and males, respectively. It is suggested that the groundwater should be chemical and biological denitrification for nitrate removal before being used for drinking purposes. The findings of this work can help policymakers to solve groundwater pollution problems and ensure healthy drinking water in such intensive agricultural basins and other similar regions worldwide.

Keywords: EWQI; Groundwater hydrochemistry; Health risk assessment; Nansi Lake Basin; Nitrate pollution.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Child
China
Environmental Monitoring / methods
Groundwater* / chemistry
Humans
Lakes
Nitrates / analysis
Water Pollutants, Chemical* / analysis
Water Quality

Substances

Nitrates
Water Pollutants, Chemical