环境科学 第6讲水体 Freshwater 北京大学环境科学与工程学院
北京大学环境科学与工程学院 第6讲 水 体
Outline 环境科学 ·水圈与水循环 ·水资源 ·水污染 ·中国水资源 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Outline • 水圈与水循环 • 水资源 • 水污染 • 中国水资源
环境科学 水圈与水循环 北京大学环境科学与工程学院
北京大学环境科学与工程学院 水圈与水循环
The Water Issue 环境科学 ● Although water covers about 70%of the Earth's surface. over 97%is saltwater.Of the less than 3 percent that is freshwater,only a tiny fraction is available for human. Third World Water Forum stated that currently 450 million people in 29 countries lack water. 。 About 25%of the world's people do not have access to safe drinking water (WHO) According to the UN (2002),by 2025 one in three people globally could be threatened with a shortage of freshwater. According to UNEP,5-10 million deaths occur each year from water-related diseases. 北京大学环境科学与工程学院
北京大学环境科学与工程学院 The Water Issue • Although water covers about 70% of the Earth’s surface, over 97% is saltwater. Of the less than 3 percent that is freshwater, only a tiny fraction is available for human. • Third World Water Forum stated that currently 450 million people in 29 countries lack water. • About 25% of the world’s people do not have access to safe drinking water (WHO) • According to the UN (2002), by 2025 one in three people globally could be threatened with a shortage of freshwater. • According to UNEP, 5-10 million deaths occur each year from water-related diseases
Freshwater resources 环境科学 -Groundwater(20.58%) 1c脚 Freshwate Soil(0.01%) Rivers and lakes (0.02%) Groundwater(0.50% Ice and glaciers (1.90%) 北京大学环境科学与工程学院 al wate
北京大学环境科学与工程学院 Freshwater resources
Major stocks of water ® volume %of %of 环境科学 (1000 km3)total water total freshwater Salt water Oceans 1338000 96.54 Saline/brackish groundwater 12870 0.93 Salt water lakes 85 0.006 Inland waters Glaciers,permanent snow cover 24064 1.74 68.7 Fresh groundwater 10530 0.76 30.06 Ground ice,permafrost 300 0.022 0,86 Freshwater lakes 91 0.007 0.26 Soil moisture 16.5 0.001 0.05 Atmospheric water vapour 12.9 0.001 0.04 Marshes,wetlands* 11.5 0.001 0.03 Rivers 2.12 0.0002 0.006 Incorporated in biota 1.12 0.0001 0.003 Total water 1386000 100 Total freshwater 35029 100 b起totals may not add erac的y due to rounding Marshes.e的n的3ndw3 ter incorporated in biota3 e often salt and freshw3起r 环境科学与工程学院
北京大学环境科学与工程学院
Freshwater resourcet境科学 100 liters (26 gallons) Total water 100% 3 liters (0.8 gallon) Fresh water 3% 0.003ier (1/2 teaspoon) Readily available fresh water 0.003% 北京大学环境科学 3程学院
北京大学环境科学与工程学院 Freshwater resources P3
环境科学 Water availability by sub-region in 2000 (1 000 m3 per capita/year) Map shows water availability measured in terms of 1 000 m3 per capita/ VRI 2000 anc catastrophically low 1020 ▣>2.0to5.0 low >5.010.0 m100o200 ■>20.0 very high 北京大学环境科学与工程学院
北京大学环境科学与工程学院
Water Shortage 环境科学 w-Hil C Inc.Permission required forr No vulnerability Medium vulnerability High vulnerability No data 北京大学环境科学与p3学院
北京大学环境科学与工程学院 Water Shortage p3
水问题的严重性 环境科学 The costs of water-related diseases two billion people are at risk from malaria alone,with 100 million people affected at any one time,and 1-2 million deaths annually痢疾 about 4 billion cases of diarrhoea and 2.2 million deaths annually:this is the equivalent of 20 jumbo jets crashing every day腹泻 intestinal worms infect about 10 per cent of the population of the developing world肠内寄生虫 ·about6 million are blind from trachoma沙眼 2O0 million people are affected with schistosomiasis血吸虫病 Souroes:CSD 1997a.WHO and UNICEF 2000 北京大学环境科学与工程学院
北京大学环境科学与工程学院 血吸虫病 沙眼 腹泻 痢疾 肠内寄生虫 水问题的严重性