water pollution in HK 作文

Water pollution is increasingly becoming a large problem that we as humans need to confront. Water is our most valuable resource. Just think of how much we humans are dependent upon clean water .

Besides the fact that we drink the water, we use it for irrigation of farm fields, cooking, washing clothes, flushing toilets, etc. and every industrial process requires water to function. Everyone knows that the Earth's surface is covered by 70% water, so why fuss over protecting water? Only 3% of all water is fresh and drinkable and of that 3%, 75% is frozen in polar ice caps, which leaves a grand total of only 1% of the Earth's surface water that is readily available for consumption After taking that fact into account, one can see why the conservation and protection of our remaining water supply is so vital.

The major sources of water pollution are organic pollution, agricultural pollution, runoff, toxic waste, and thermal pollution.

Organic pollution is becoming more and more pressing on the environment, because of the growing population of the world. It's a simple concept, the more people there are in one area, the more waste they will produce. For example, in a city there are so many people that the sewage plants and the environment can't take care of all of the waste and function in its usual manner The sewage plants do their best, but the secondary discharge that gets into the water supply causes great problems. The excess waste acts as a food source for algae and the growth rate is uncontrollable. The algae will deposit on the shore and the water is clouded with algae. This situation is known as eutrophication, When excess waste is added to the water the body of water can no longer control the growth of the algae and the water soon becomes algae ridden and oxygen depleted. The water becomes oxygen depleted, because the dead algae goes to the bottom and uses the oxygen in the deeper water to decompose, but if there is too much dead algae all the oxygen is depleted.

篇文啲開頭可以係 WSD網址揾.2.原因係人人都用水,乾淨的人,令我們整日快樂(照譯英),3.由於以乾淨的水源可以飲用,煮飯,生活才可繼續,生命延續進化.4.環境周遭會直接人的情緒,包括心情,間接影響下一代成長發展..5.總結,唔好講咁多,要珍惜食水.

2012-04-21 18:13:13 補充：
Introduction:seeWSD.2reasons:everyone lives with water,clean,all day happy as live depends on water and food.3Clean water for drinking, cooking; our life can continue-the evolution of life.4The environment affects emotions,including good/bad mood,indirectly affects the next generation's development.