Characterization of drinking groundwater quality and assessment of human health risk in Xin’an spring basin, a typical mining and karst area of the northern China

Abstract

Groundwater is an important natural resources of drinking water in mining area in Xin’an spring basin, northern China. To foster the sustainable development and utilization of groundwater, a total of 332 groundwater samples, including 147 pore groundwater, 95 fissure groundwater and 90 karst groundwater, were collected and hydrochemical parameters were applied to assess the groundwater quality and human health risks caused by oral ingestion. The results showed that the major chemical components of groundwater in Xin’an spring basin were HCO3−, SO42−, NO3−, Cl−, Ca2+, Mg2+, Na+, total hardness (TH), and total dissolved solids (TDS). The contents of TDS, TH, SO42−, NO3−, F−, Fe, Mn, Pb, and As in groundwater were exceed the standard of groundwater quality (SGQ) limits. The main hydrochemical types of groundwater were HCO3-Ca·Mg and SO4·Cl–Ca·Mg. The factors controlling the groundwater chemistry mainly were mineral weathering, evaporation, cation exchange, and anthropogenic input. The results of water quality assessment showed that the karst and fissure groundwater in study area was mainly excellent-good quality water, while pore groundwater was mainly good-medium quality water. The poor and extremely poor quality water was mainly distributed in Changzhi basin, and the greater contribution made by Pb, Mn, NO3−, Fe, SO42−, TH and TDS. The range of hazard index (HI) values of groundwater was 0.28 to 27.79, and the HI values mainly contributed by NO3−, F−, As, ingestion rate (IR) and exposure duration (ED). The cumulative carcinogenic risk (CCR) values ranged from 1.5 × 10–7 to 2.78 × 10–3, and the greater contribution made by Cr, As, Cd, IR and ED. The results of health risk assessment suggested that some parts of the study region may pose a significant non-carcinogenic risk and a high probability in developing cancer to local residents, and infants were at greatest risk to health, followed by children and adults, while teenagers were at least at risk. This study will provide a deeper insight into the water quality situation and geochemical evolution of groundwater in Xin’an spring area, and will assist decision-makers to formulate management strategies of drinking water safety for the study area.