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Water

We begin this Chapter with the disturbing statement that world supplies of fresh water are in jeopardy, not only in the U.S., but in China, India and other large economies. Water is becoming the most abused natural resource. The threat to fresh water is of two types:

Quantity

Diminishing quantities from underground aquifers, owing to growing depletion arising from both industrialization and population growth: The 2014 London World Water Summit projected that world water consumption will double between 2014 and 2025.

Widespread contamination and pollution of all water on the planet, only 1.5 percent constitutes fresh water. 97 percent is saltwater in oceans. Water usage is heavily concentrated in agriculture. 93 percent of water consumption occurs in agriculture, mainly for irrigation. (Note: the figures are for water consumed : water that becomes unavailable for other uses).

Of total water consumption, only 7% is for household and industrial use.

Quality

Sanitation challenges affecting water resources continue to mount. To illustrate, contaminated water worldwide is a leading cause of infant mortality from diarrhea and related gastric problems (2 million children a year die). Contaminated water in many areas has led to widespread cancers of the digestive tract.

*Measures the amount of water left over after utilization by the population of each region.
Some worldwide water data potential water availability worldwide (cubic meters)* 2010
North America 17,400
South America 38,300
Europe 4,240
Africa 5,720
Asia 3,920
Australia and Oceania 83,600
Total annual rainfall in millimeters per year
Eastern U.S. 1,000 - 2,000
Western U.S. 250 - 5,000
Amazonian Rain Forest (Brazil, Colombia, Peru) 2,000 - 3,000β
Northern Chile <250
Sahara <250
Indonesia 2,000 - 3,000
S.E. Asia 1,000 - 3,000
South China 1,000 - 2,000
North China 250 - 300

This experience of China is illustrative concerning problems both water of availability and water quality. Water is relatively plentiful in South China; but very scarce in North China (see Table 18-2). And chemical water pollution as we will see is widespread (if we considered also bacterial pollutants, the problems are even worse).

Chinese rivers are disappearing. 1990s, China had 50,000 rivers with catchment areas of over 100 square km or more. Now, the numbers of such rivers is down to 23,000 : 27,000 rivers have disappeared as rivers in 60 years.

Moreover, 80% of the rivers flowing through China are heavily polluted. Even worse, research reported in the November 11, 2011 issue of Science shows that fully 90% of Chinese shallow groundwater is polluted. 37% of this water is so polluted that it cannot even be treated for use as drinking water. The costs to China yearly from water pollution issues are estimated at 2.3% of GDP. And 70% of Chinese get their drinking water from underground.

In many villages in China, water from contaminated rivers or groundwater is the only source of water available. Every year about 190 million Chinese (15% of the population) become ill from bad water. Every year 60,000 Chinese die because of water pollution. This has happened for two main reasons:

  • In China’s very rapid economic growth experience after 1990 environmental issues were decidedly secondary – incentives were to maximize output, even at heavy costs to air and water quality.
  • China does not have laws on groundwater contamination. This is a striking example of the importance of institutions in economic development (see Chapter___).

Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
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cm
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A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
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Can you compute that for me. Ty
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emma Reply
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what is inorganic
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Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
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A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
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you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
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progressive wave
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Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
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Source:  OpenStax, Economic development for the 21st century. OpenStax CNX. Jun 05, 2015 Download for free at http://legacy.cnx.org/content/col11747/1.12
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