Hydrogeochemistry and Quality Assessment\nof Groundwater Based on Fuzzy Analytical\nHierarchy Process: A Case Study From Sulin\nCoal-Mining District in Northern Anhui, China

Abstract

Sulin coal-mining district is characterized by rich coal resources, and its shallow groundwater (SG) and mid-layer groundwater (MG) are the main freshwater source for drinking, agriculture, and industrial purpose. However, frequent mining activities had damaged groundwater systems. Therefore, it is necessary to understand the hydrogeochemical characteristics and determine the status of groundwater quality. To achieve a higher degree of accuracy in water quality assessment, this paper proposed a fuzzy analytical hierarchy process (AHP) which combined the fuzzy analysis model and AHP model. The results showed that Na+ and HCO3 were the dominant cation and anion in both SG and MG, respectively. In addition, TDS, SO4 2-, Cl-, Mn, Na+, and NO3 of SG and TDS, SO4 2-, Cl-, Mn, Na+ and Fof MG were higher than the grade III limits of Chinese groundwater standards. Analysis with molar ratios of major ions suggested that the geochemical composition of SG and MG were mainly determined by the dissolution of silicates. The fuzzy AHP evaluation results indicated that the samples of SG and MG within the III-type water accounted for 90.64% and 94.44%, respectively, and their water quality was good, which were consistent with the actual natural conditions of the study area.