Hydrogeochemical and anthropogenic controls on quality and quantitative source-specific risks of groundwater in a resource-based area with intensive industrial and agricultural activities

Abstract

Groundwater contamination in resource-based cities/areas generally suffers from complex superposition of multiple hydrogeological and anthropogenic factors, of which control mechanism and quantitative allocation of health risks need more in-depth understanding. Thus, integrated-weight water quality index (IWQI) and source-specific health risk assessment model built on the combination of Hazard Index (HI) and Total Cancer Risk (TCR) standard models and Positive Matrix Factorization (PMF) model were utilized to investigate the controls simultaneously from hydrogeological processes and anthropogenic activities on groundwater quality and quantitative health risks in a representative resource-based city/area (i.e., Handan area). The results indicated that localized-disequilibrium of hydrochemical characteristics was mainly controlled by weathering processes of outcropped rocks and aquifers with different lithology. Most of groundwater (94.47 %) can be classified as excellent and good levels, while groundwater quality deterioration occurred in eastern plain. Traditional hydrochemical analysis approaches together with saturation index (SI) and Pearson's correlation analysis indicated that water-rock interaction, semi-arid climate, positive cation exchange and agricultural activities can intensify groundwater quality deterioration. There was a moderate non-carcinogenic risk and a high carcinogenic risk induced by PTMs in groundwater. Non-carcinogenic risk was mainly caused by heavy industry (34.93 %) and agricultural activities (32.94 %), while carcinogenic risk was dominated by agricultural activities (37.92 %) and heavy industry (35.58 %). Coal mining accounted for 18.16 % of non-carcinogenic risk and 20.98 % of carcinogenic risk respectively. Traffic contamination and geogenic source merely made a minor contribution. These results suggested that source-specific health risk assessment model can clearly quantify the allocations of different sources to the health risks, which was worth being popularized in the field of groundwater researches. This study contributed to profound understanding on groundwater quality deterioration and contamination collectively induced by various hydrogeological and anthropogenic factors, and provided a reference for developing contamination source-oriented countermeasures of groundwater pollution to other resource-based cities/areas worldwide.