Spatio-temporal analysis of groundwater chemistry, quality and potential human health risks in the Pinggu basin of North China Plain: Evidence from high-resolution monitoring dataset of 2015–2017

Abstract

Long-term monitoring reveals the spatio-temporal evolution of groundwater chemistry, quality and human health risk, providing detailed and robust evidence for groundwater utilization. The Pinggu basin of North China Plain is significant place reserving drinking groundwater. 184 samples were collected from fifty-eight monitoring wells during 2015-2017. Ratios of major ions and geochemical modelling were carried out to clarify the factors controlling the hydrogeochemical compositions. Groundwater displayed the hydrochemical type of Ca-HCO3 and its compositions were determined by calcite and dolomite dissolution with cation exchange reaction. NO3− contamination was derived from agriculture activities. The entropy-weighted water quality index (EWQI) results indicated the majority of total groundwater samples except those in some southwestern and northwestern parts were able to meet the requirement of drinking purposes. Groundwater quality was affected by the total dissolved solid, Ca2+, HCO3− and NO3− concentrations. Human health risk of groundwater drinking depended on the NO3− concentration and followed the order of children > adult females ≈ adult males, according to the hazard quotient (HQ) used in the human health risk assessment (HHRA) model. Protection and management measures for groundwater resources were made for the Pinggu basin and other similar areas, based on the spatio-temporal analysis of groundwater chemistry, quality and potential human health risks.