Spatial assessment of tap-water safety in China

The quality of drinking-water supplies is of fundamental importance to public health and sustainable development. Here, we provide a spatial assessment of the tap-water quality across mainland China. We examine natural and anthropogenic origins of low quality as well as its association with public health risks. By quantifying key indicators, including total organic carbon, ionic conductivity and disinfection by-products (DBPs), we find that precipitation is a crucial factor driving the change of organic matter content and ionic conductivity of tap-water, especially for arid and semi-arid regions. Although the concentration of DBPs is closely related to the organic matter content, the occurrence of highly toxic DBPs is more subject to anthropogenic factors such as economic development and pollution emission. We show that nanofiltration is an effective point-of-use treatment to reduce the adverse effects of DBPs. The present results highlight the potential health hazards associated with low-quality drinking water, suggesting that countries and regions experiencing rapid socioeconomical development might face high levels of DBP toxicity and should consider adoption of sustainability solutions.