Source apportionment and health risk assessment of arsenic contamination in groundwater in Xinxiang city based on the PCA-PMF model and WQI method.

Abnormal arsenic levels in Xinxiang City's groundwater threaten drinking water safety and agricultural production. To investigate arsenic sources and health risks and support targeted pollution control and public health management, this study analyzes groundwater hydrochemical characteristics, identifies key determinants of chemical composition, and examines correlations between arsenic and characteristic ions. Principal component analysis (PCA) and positive definite matrix factorization (PMF) were combined to identify major arsenic sources, while the weighted arithmetic water quality index (WAWQI) and a health risk model were used to assess groundwater suitability for consumption and population exposure risks.The results indicate that arsenic-rich groundwater is mainly associated with weakly alkaline, reducing environments, elevated iron concentrations, and high HCO3- and NH4+ levels. Agricultural irrigation also contributes significantly to arsenic accumulation. PCA and PMF analyses identify three dominant factors: the iron-arsenic migration factor related to reduction processes (40.7%), carbonate mineral dissolution under weak runoff conditions (8.8%), and a bicarbonate-rich mixing factor affected by irrigation (50.5%). The WAWQI classified 42.86% of samples as unsuitable for drinking, with As controlling most high-index values. Carcinogenic risk was also dominated by As, and the mean combined risk for children was approximately 10.4 times that for adults. These results support the delineation of priority high-As monitoring zones, reduction of child exposure, and coordination of drinking-water protection with irrigation and fertilizer management in Xinxiang.