Unveiling water quality and health risks from groundwater chemicals in Poyang Lake basin of China: a sophisticated analysis

The results unveils pronounced spatial variability across key hydrochemical parameters: pH ranges from 3.05 to 11.09, total dissolved solids (TDS) from 25.38 to 1,635.21 mg/L, Mn from below detection limits to 19.93 mg/L, COD from below detection limits to 8.57 mg/L, and TH from 9.47 to 905.78 mg/L. A notable proportion of samples breach the Class III groundwater quality standards, with 38% for Mn, 39% for COD, and 15% for NH_4⁺ . The Piper diagram analysis categorizes the primary groundwater type as HCO_3^- -Ca, with a secondary Cl-Ca-Mg type. Through the EWQI assessment, while the overall water quality is deemed acceptable, we identify 56 sites with EWQI values indicative of poor to very poor quality, predominantly influenced by Mn and NH_4⁺ . The irrigation risk assessment highlights extensive areas unsuitable for irrigation, particularly within the Ganjiang River basin. Health risk assessments utilizing a deterministic model reveal significant non-carcinogenic risks from F^- and NO_3^- in groundwater, especially for children. However, our Monte Carlo simulation indicates that the probabilities of F^- and NO_3^- posing non-carcinogenic health risks are virtually zero, suggesting that the deterministic assessment may have overestimated the health risks. This study provides critical insights into the groundwater quality and health risks in the Poyang Lake basin and underscores the necessity for targeted water management strategies to mitigate pollution sources and safeguard public health.