Water pollution is caused by waste from factories and cities.Oceans are able to clean themselves, but certain seas,once they become dirty, are not able to do so.One example is the Mediterranean which lies between Europe and Africa.It has onlyeone narrow entrance to the ocean in the west.On quarter of the shores of the Mediterranean are polluted and are no longer safe for swimming, as a lot of diseases are present in the water.In most places it is not safe to eat the fish.
水的污染是由于工廠和城市的廢物引起的。大洋能夠自身清除污染,但是某些海域一旦被污染,卻沒有自身清污的能力。位于歐洲和非洲之間的地中海就是一個(gè)例子。它只在西部有一個(gè)狹窄的通往大洋的入口。四分之一的地中海海岸被污染了,而且由于水中帶有大量病菌,所以在水中游泳就不再安全了。大多數(shù)地方,吃魚也不保險(xiǎn)。