Twofold significance of ground water pollution prevention in China's water pollution control

Contaminants from Non-point Sources(NPS) not only enter rivers,lakes,and inshore through overland flow and pollute surface water bodies but also infiltrate into the subsurface and pollute ground water.The contaminated ground water eventually flows into river,lakes,or inshore and also pollutes surface water bodies.The significance of ground water pollution prevention is thus twofold: one is to protect groundwater as drinking water sources and the other is to prevent surface water pollution.However,most studies in China so far have been focused on protecting ground water as drinking water sources.Little attention has been paid to studying how contaminants in ground water move into surface water bodies and how much they contribute to surface water pollution.In this paper,ground water contamination by nitrate from agricultural NPS is used as an example to emphasize the twofold significance of ground water pollution prevention.It is hypothesized that ground water contaminated by NPS may be a nutrient source leading to eutrophication of China's major rivers,lakes,and inshore waters.More research is needed in the areas of ground water contamination by NPS for better watershed management and more effective control of China's water pollution.