Spatial assessment of drinking water flavor in China: Revealing regional disparities and underlying drivers

Drinking water flavor, a critical water quality metric, exhibits substantial regional variations across China, influenced by local geology and chemistry. Despite growing consumer concerns about water flavor, a spatial assessment of the determinants of water flavor in China has been notably lacking. This study bridges this gap by conducting a spatially comprehensive analysis of 78 tap water samples throughout China. A reliable flavor evaluation method, alongside advanced statistical techniques, including correlation analysis, principal component analysis (PCA), and spatial autocorrelation analysis, were applied to identify the drivers behind regional flavor differences. The findings reveal four predominant types of flavor variations attributed to distinct organic and inorganic factors. The spatial distribution patterns of key parameters impacting flavor were clarified by Moran's I statistic. Notably, the South-to-North Water Diversion Project is highlighted for its role in enhancing water flavor by modifying the chemical composition of water in recipient regions. Dissolved organic carbon (DOC), trihalomethanes (THMs), and the fluorescence index (Φ_IV,n) are identified as non-negligible supplementary indicators of water flavor. The research highlights the need for region-specific strategies to enhance the flavor of drinking water nationwide.