swimming, as a lot of diseases are present in the water. In most places it is not safe to eat the fish.

Lakes also have the same problems. Lake Baikal in Asia was once the cleanest in the world, with over 700 different kinds of plant and animal life. Now, however, the waters of this great lake, which is also the world＇s deepest (over 1,740 metres), have been dirtied by waste from a chemical factory.

In 1989 an oil tanker hit a rock off the northwest coast of Alaska. 35,000 tons of oil poured into the sea. The accident was one of the worst in history. More than 34,000 birds and 10,000 animals were killed. 4,800 square kilometres of ocean were polluted.

水污染造成的浪费，是工厂和城市。海洋能清洗自己，但某些海域，一旦变脏，不能这样做。一个例子是地中海的欧洲和非洲之间的谎言。它onlyeone狭窄的入口，在西部海洋。

论地中海沿岸季度受到污染，不再适合游泳安全作为很多疾病，在水存在。在大多数地方并不安全食用鱼。

湖泊也有同样的问题。在亚洲的贝加尔湖曾经是世界上最清洁，超过700的植物和动物生命不同。但是现在，这个伟大的湖泊，也是世界上最深的（超过1740米的水域），已弄污废料化学工厂。

在1989年创下油轮关闭阿拉斯加西北海岸的岩石。 35,000吨油倒入大海。这次事故是最糟糕的历史。超过34,000和10,000鸟类动物死亡。 4,800平方公里的海洋受到污染。