검색어 입력폼

[자연과학](research paper) water pollution

저작시기 2004.03 |등록일 2005.04.03 워드파일MS 워드 (doc) | 7페이지 | 가격 21,000원

소개글

water pollution

목차

Introduction
Body
Chemical pollution
Oxygen-depleting Substances
Nutrients
Conclusion

본문내용

Over 70% of the Earth’s surface is water. Water is the most valuable natural resource. With out food we can live over a week, but with out water we can not live over a week. Such important water has been polluted. Water pollution is a very serious situation in our society. Many creatures that live in the sea have been dying. It also influences humans.
We have to prevent water pollution. Water is very important for humans and other creatures.
What is the meaning of water pollution? It is that water is not natural situation; water is polluted by dirty matters. In other words, water is changed chemically, physically and biologically by waste water, sewage and excrementitious matter’s effects.
다운로드 맨위로