[Distribution, Source Apportionment, and Health Risk Assessment of Inorganic Components in Groundwater in the Plain Area of Manas River Basin in Xinjiang].

Abstract

Groundwater is the main source of water for daily life, agricultural irrigation, and industrial production in the Manas River Basin （MRB） in Xinjiang. To explore the spatial distribution and sources of inorganic components in groundwater and their negative effects on human health, 37 groundwater samples were collected in the plain area of MRB. The spatial distribution, sources, and potential health risks of inorganic components in groundwater were analyzed using Kriging interpolation, PMF source analysis, Pearson correlation analysis, and a health risk assessment model. The results showed that all of the groundwater in the area was weakly alkaline. Groundwater TDS and Cl^- had similar distribution characteristics, being higher in the eastern part of the plain area. The high SO₄^2- area was mainly distributed in the periphery of Manas County and the edge of the Gurbantonggut desert. The distribution of groundwater NO₃^--N, which was greatly affected by human activities, showed spatial heterogeneity, and the high-value areas were mainly distributed in urban areas. Arsenic （As）, fluoride （F）, and iodine （I） were important inorganic components affecting groundwater quality, with over-limit rates of 51.35%, 45.95%, and 51.35% according to the Standard for Groundwater Quality （GB/T 14848-2017）. High As, F, and I groundwater was distributed in the low plain area north of the West Bank Canal, which had a small topographic slope, hydraulic gradient, and aquifer particles with weak groundwater runoff intensity and was conducive to the enrichment of groundwater As, F, and I. Source apportionment showed that groundwater in different aquifers had similar sources or evolution processes. The concentration of inorganic components was controlled by leaching concentration, point source pollution under the geological environment-domestic sewage-agricultural irrigation, agricultural activities, point source pollution caused by domestic sewage, an alkaline-reducing environment, and ion exchange. Health risk assessment showed that As in groundwater was the main inorganic component threatening human health. The non-carcinogenic risk for children and adults could be ignored, whereas the carcinogenic risk cannot be ignored, and children were more sensitive to the risk of cancer caused by inorganic substances in the groundwater. Therefore, more attention should be paid to As exposure to drinking water safety, especially for children.