Water pollution means adding something to the water or changing its properties such that it is no longer safe to use it for the purpose you want. Changes brought by water pollution are harmful to living things.
Look at the rivers and seas in your area. Are they clean enough to swim in? Are they clean enough to use for cooking and drinking? Chemical waste from factories can make our waters too acidic, to hot or too dirty. Because of this, it can no longer be used for drinking, cooking or swimming. It can only be used for traveling.
Washing clothes inthe river can cause pollution when using detergents or soaps that are non-biodegradable. These cannot be reduced into simple substances that can be useful again to nature (to plants and animals).
Dumping garbage into the river can also cause water pollution. The decay of garbage uses up oxygen gas in the water. This is not good for aquatic animals and can cause widespread death of fish called fish kill. You know there is fish when you see plenty of dead fish floating on the water. This problem is similar to having too many water hyacinths in a body of water. Fish will have hard time breathing because oxygen from air cannot easily dissolve in the water that is covered with floating plants.
Human waste can also pollute rivers and seas as well as underground water.
Red tide can also be related to garbage dumping in seas. There are months when red-tide organisms bloom or increase in number because of so much substances. Filter feeders like shellfish accidentally eat some of the red-tide organisms. Humans who eat the infected shellfish can get sick and die. Mercury poisoningfrom eating infected fish is another result of water pollution.
If your kitchen sinks drains directly into rivers and seas without passing any treatment, we are guilty of polluting our rivers and seas. We are like those who dump their garbage into the sea.
Oil spills cause water pollution. These may happen when accidents with sea vessels occur at sea. This is not only harmful to fish and other sea creatures, but it is also harmful to other animals like birds. Birds covered with oil can no longer fly. They have to be washed thoroughly so their wings and feathers can function again.
A special case of land and water pollution is where seawater seeps inland, thus making both the soil and the groundwater salty. Small islands and coastal areas are prone to this kind of pollution. The people cannot use the water from their wells for drinking. In some remote areas, the roofs of houses are designed and constructed in such a way as to enable the owners to collect rainwater and store it for drinking.
The last case of water pollution is brought about by natural causes. There is not much people can do about them but to avoid the areas involved.
If you find this article interesting, you might also want to read these: