Everyone knows that more than 10% of the surface area of the earth is covered by water. water is really quite important to all the creatures since no life can exist without water. But in recent years, more and more water are polluted by human activities, and water pollution has become a problem that everybody should face today. The three main sources of water pollution are domestic sewage, agricultural run off and industrial effluents.
For the domestic sewage, it refers to waste water that is discarded from households. It's large by volume and contains impurities such as organic materials and plant nutrients that tend to rot. Hence it is also very likely to contain disease-causing microbes. But the problem is that in some countries, there is no proper desposal of domestic sewage. In some parts of China, like my hometown, Jinlin, a lot of domestic sewage are discharged into the Songhua River without any proper treatment most of the time. What's more, today many people dump their garbage into streams, lakes, rivers, and seas, thus making water bodies the final resting place of cans, bottles, plastics and other household products, and some of them contain harmful chemicals like the synthetic detergents.
For the agricultural run off, the common use of fertilizers and pesticides will cause water pollutions. The use of land for agriculture and practices followed in cultivation greatly affect the quality of ground water. It's said that the high nitrate content in groundwater is mainly from irrigation run-off from agricultural fields where chemical fertilizers have been used indiscriminately. And when these chemicals are washed away by the rains, they will flow to the river nearby and cause the pollution again.
For the industrial effluents, water pollution is mainly caused by the industrial waste water which contains specific and readily identifiable chemical compounds. Most of these compounds are highly toxic. As the number of industries grown rapidly in recent years, more and more waste water is produced. Hence a big amount of money is needed for the disposal of these waste water. But the problem is that most of the developing countries can't afford so much money for treating the waste water, they also don't have any adequate effluent treatment facilities. Thus, the crisis of water pollution occured.
Actually, I think water pollution really has a lot of serious effects. It's not only devastating to people but also to animals, fish and birds. Polluted water is unsuitable for drinking, recreation, agriculture and industry. It diminishes the aesthetic quality of lakes and rivers. More seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Eventually, it is a hazard to human health. Nobody can escape the effects of water pollution.
As a student, I think we should also contribute to the protecting of the water. We have only one earth, we should not harm it any more! If anybody can contribute a little, I believe the problem of water pollution will be solved eventually in future.
No comments:
Post a Comment