Water PollutionMy classmates and I had a tour this We had a good But meanwhile I knew that water pollution in our country was becoming more and more On our way， we could see women washing clothes in the Litter was floating on the Waste water produced by a chemical factory was being discharged into the We did not see any fish in the The river was not so clear as Water quality was very I am worried about it because water is important to all living Man can not live without I hope people pay more attention to this problem， especially the Try to control the pollution of water as early as At last I would like to say， "To protect water is to protect "今年春天，我和我的同学去春游，我们玩得都很高兴。但同时，我也了解到我们国家的水污染变得越来越严重了。沿途我们看到许多妇女在河边洗衣，河面上漂着垃圾，一家化工厂正将废水排入河中。河中看不到一条鱼，河水也不像从前那样清澈了，水质很差。对此我深感担忧，因为水对于所有生物都非常重要。没有水人类将无法生存。我希望人们能多关注这个问题，特别是政府部门，争取及早解决水污染问题。最后，我想说“保护水就是保护生命”。说明：以前替别的同学写的，请参考使用。
Water pollutionWater pollution is a major problem in the global It has been suggested that it is the leading worldwide cause of deaths and diseases， and that it accounts for the deaths of more than 14，000 people An estimated 700 million Indians have no access to a proper toilet， and 1，000 Indian children die of diarrheal sickness every Some 90% of China's cities suffer from some degree of water pollution， and nearly 500 million people lack access to safe drinking In addition to the acute problems of water pollution in developing countries， industrialized countries continue to struggle with pollution problems as In the most recent national report on water quality in the United States， 45 percent of assessed stream miles， 47 percent of assessed lake acres， and 32 percent of assessed bay and estuarine square miles were classified as pollutedWater is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use， like serving as drinking water， and/or undergoes a marked shift in its ability to support its constituent biotic communities， such as Natural phenomena such as volcanoes， algae blooms， storms， and earthquakes also cause major changes in water quality and the ecological status of Causes of water pollutionThe specific contaminants leading to pollution in water include a wide spectrum of chemicals， pathogens， and physical or sensory changes such as elevated temperature and While many of the chemicals and substances that are regulated may be naturally occurring (calcium， sodium， iron， manganese， ) the concentration is often the key in determining what is a natural component of water， and what is a Oxygen-depleting substances may be natural materials， such as plant matter ( leaves and grass) as well as man-made Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth， and clogs the gills of some fish Many of the chemical substances are Pathogens can produce waterborne diseases in either human or animal Alteration of water's physical chemistry includes acidity (change in pH)， electrical conductivity， temperature， and Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases in the primary productivity of the Depending on the degree of eutrophication， subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur， affecting fish and other animal
