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Water Pollution
Water pollution, from both point and non-point sources, presents serious problems that not only damage wetlands and other natural resources but also threaten public health and livelihood. One doggerel by local people vividly depicts the dynamics of water pollution in Eastern China over the last 50 years: ‘‘Cleaning rice and vegetable in the 1950s; washing cloth in the 1960s; becoming dirty in the 1970s; disappearing of fish and shrimp in the 1980s; causing bodily injury in the 1990s.’’
In the early 1970s, water quality began to show effects of increased discharge of waste water from industrial and domestic activities and runoffs from non-point sources, such as fertilizers used in agriculture. Over the period of 1980–2000, the waste water discharge increased by 180% from industry and 380% from residential sources, and much of the waste water was poorly treated or untreated and full of pollutants. During 1950–2000, the annual consumption of fertilizers in China increased by 530 times, whereas the area of aquatic culture increased by 6.3 times and its production by 125 times. Much of the fertilizers (50%–70%) ended up in the natural wetlands either by direct discharge or by accumulation of runoffs.
Excessive nutrient loading and poorly treated waste water
discharge greatly affected water quality of rivers and lakes.
Among the 1200 monitored rivers, 70.8% was polluted and 63.1% were severely polluted. Fishes and shrimps disappeared from 33% of the total length of these rivers. The Huaihe, Haihe, and Liaohe in temperate China were among the most polluted rivers. It was reported in 2000 that 75% of lakes were eutrophic and that 20% of these lakes lost their basic ecosystem functions, especially those nearby the cities with rapid economic development. The Chaohu, Taihu, and Tianchi lakes were severely polluted, and their ecosystem structure was almost collapsed. The gloomy picture of the polluted wetlands can be translated into an alarming crisis of public health, because of the limited freshwater resources in China. China has 2800 km3 freshwater resources (i.e., about 2206 m3 per person). However, because of water pollution, only 40%–50% of the freshwater resources can be used directly for human consumption, which makes China one of the lowest per capita freshwater use in the world. How to effectively use the freshwater resources (e.g., by increasing wetland areas and thus, storage, or by cleaning up the polluted waters) will remain a daunting challenge for China in the years to come.
Data come from:
S. An, H. Li, B. Guan, C. Zhou, Z. Wang, Z. Deng, Y. Zhi, Y. Liu, C. Xu, S. Fang, J. Jiang and H. Li, China’s Natural Wetlands: Past Problems, Current Status, and Future Challenges, Royal Swedish Academy of Sciences, 2007
Water pollution, from both point and non-point sources, presents serious problems that not only damage wetlands and other natural resources but also threaten public health and livelihood. One doggerel by local people vividly depicts the dynamics of water pollution in Eastern China over the last 50 years: ‘‘Cleaning rice and vegetable in the 1950s; washing cloth in the 1960s; becoming dirty in the 1970s; disappearing of fish and shrimp in the 1980s; causing bodily injury in the 1990s.’’
In the early 1970s, water quality began to show effects of increased discharge of waste water from industrial and domestic activities and runoffs from non-point sources, such as fertilizers used in agriculture. Over the period of 1980–2000, the waste water discharge increased by 180% from industry and 380% from residential sources, and much of the waste water was poorly treated or untreated and full of pollutants. During 1950–2000, the annual consumption of fertilizers in China increased by 530 times, whereas the area of aquatic culture increased by 6.3 times and its production by 125 times. Much of the fertilizers (50%–70%) ended up in the natural wetlands either by direct discharge or by accumulation of runoffs.
Excessive nutrient loading and poorly treated waste water
discharge greatly affected water quality of rivers and lakes.
Among the 1200 monitored rivers, 70.8% was polluted and 63.1% were severely polluted. Fishes and shrimps disappeared from 33% of the total length of these rivers. The Huaihe, Haihe, and Liaohe in temperate China were among the most polluted rivers. It was reported in 2000 that 75% of lakes were eutrophic and that 20% of these lakes lost their basic ecosystem functions, especially those nearby the cities with rapid economic development. The Chaohu, Taihu, and Tianchi lakes were severely polluted, and their ecosystem structure was almost collapsed. The gloomy picture of the polluted wetlands can be translated into an alarming crisis of public health, because of the limited freshwater resources in China. China has 2800 km3 freshwater resources (i.e., about 2206 m3 per person). However, because of water pollution, only 40%–50% of the freshwater resources can be used directly for human consumption, which makes China one of the lowest per capita freshwater use in the world. How to effectively use the freshwater resources (e.g., by increasing wetland areas and thus, storage, or by cleaning up the polluted waters) will remain a daunting challenge for China in the years to come.
Data come from:
S. An, H. Li, B. Guan, C. Zhou, Z. Wang, Z. Deng, Y. Zhi, Y. Liu, C. Xu, S. Fang, J. Jiang and H. Li, China’s Natural Wetlands: Past Problems, Current Status, and Future Challenges, Royal Swedish Academy of Sciences, 2007