Assessment of hydrogeochemical characteristics and quality of groundwater resources in relation to risk of gastric cancer: comparative analysis of high- and low-risk areas in Iran

The chemical quality of groundwater supplies in two high-risk area (HRA) and low-risk area (LRA) for gastric cancer in Iran was assessed through hydrogeochemical analysis and water quality indices. For this aim, Piper and Schoeller diagrams and water quality index (WQI) were applied. In addition, exposure to nitrate via drinking water and its corresponding risk were also assessed using Monte Carlo simulation technique. Data on physicochemical properties of groundwater resources were obtained from Iran Water Resources Management Company. Sampling and analysis of tap water for nitrate concentration were conducted in two cities of Shiraz (as a representative of LRA) and Ardabil (as a representative of HRA). According to Piper diagrams, the dominant hydrogeochemical facies of groundwater supplies in HRA and LRA were Na–HCO 3 (43.75%) and Ca–HCO 3 (41.77%), respectively. The predominant cations in groundwater resources of HRA were found to be Na + (68.06%) and Ca 2+ (31.94%). For LRA, the typical cations were in decreasing trend: Ca 2+ (39.64%) > Mg 2+ (18.35%) > Na + (17.26%). For two areas, HCO 3 − , SO 4 2− and Cl − were, respectively, the most frequent anions. Two-sample Wilcoxon test showed that there were statistically significant difference between two areas in terms of anions and cations concentrations ( p value