关键词: 水污染, 水质, 广义相对风险, Cox比例风险模型

Abstract: Serious water pollution problems exist in the rivers and seas in China, and our water environment is facing unprecedented crises. Using the generalized concept of relative risk and the Cox proportional hazards model, we quantify the water quality differences among the major rivers, the coastal waters and the seas, and study the changing trend over years. The results show that the water quality in the rivers improves in general (under the sense of weighted average), but that in the coastal waters and the seas are deteriorating significantly. In particular, based on the data on polluted areas (in squared kilometers) in the coastal waters, the water quality in the Yellow Sea improves, but that in the Bohai Sea, the East China Sea and the South China Sea deteriorates over the years; based on the data on the polluted areas in the seas, the water quality in the Bohai Sea, the East China Sea, the South China Sea and the Yellow Sea all deteriorate over the years. Among the coastal waters or the seas, the East China Sea is the most severely polluted.

Key words: Water Pollution, Water Quality, Generalized Relative Risk, Cox Proportional Hazards Model