Groundwater Quality and Contamination Assessment in the Main Plains of Eastern China

Based on a large amount of data obtained from the National Groundwater Contamination Investigation Project, the groundwater quality in North China plain, Huaihe River basin, the Yangtze River delta and the Pearl River delta in the eastern China was assessed with the single factor method, and the status of groundwater quality was assessed with detection limit and over-standard rate methods. The results show that the proportion of groundwater suitable for drinking directly (Ⅰ-Ⅲ level) or after proper treatment (Ⅳ level) is 47.9%, and the proportion not suitable for drinking directly (Ⅴ level) is 52.1%. The quality of shallow groundwater is slightly worse than that of the deep groundwater. The main compositions which affected the groundwater quality are natural chemical compositions, such as iron, manganese, fluorine, iodine, total hardness etc., whereas chemical compositions from human activities including three nitrogen (NO₃^-, NH₄⁺, NO₂^-) compounds, cadmium, lead and trace organic composition. The groundwater contamination caused by three nitrogen compounds is distributed with regional characteristics; on the contrary, that by heavy metals is distributed with point characteristics. The contamination caused by lead and arsenic is especially serious, and toxic organic contamination presents the characteristic of high detection rate and low over-standard rate. The National Groundwater Contamination Investigation should be promoted, and the national groundwater prevention and control planning should be organized and carried out to curb the worsening situation of groundwater contamination and protect the groundwater resources and environment in China.