Driving mechanism and sources of groundwater nitrate contamination in the rapidly urbanized region of south China.

Nitrate contamination of groundwater has become an environmental problem of widespread concern in China. We collected 899 groundwater samples from a rapidly urbanized area, in order to identify the main sources and driving mechanisms of groundwater nitrate contamination. The results showed that the land use has a significant effect on groundwater nitrate concentration (P<0.001). Landfill leakage was an important source of nitrate in groundwater in the PRD (Pearl River Delta) region, since landfill yielded the highest nitrate concentration (38.14 mg/L) and the highest ratio of exceeded standard (42.50%). In this study, the driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth. This study revealed that domestic wastewater and industrial wastewater were the main sources of groundwater nitrate pollution. Therefore, the priority method for relieving groundwater nitrate contamination is to control the random discharge of domestic and industrial wastewater in regions undergoing rapid urbanization. Capsule abstract. The main driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth.