Water pollution is caused by human actions that make water dirty and unsafe for living things. In the environment many materials and substances can mix with or dissolve in water and pollute it.
Causes of water pollution
Water can be polluted by:
- insoluble substances such as oil and plastic
- soluble substances such as soaps and fertilizers
- germs from toilet waste
Water pollution by Insoluble substances
insoluble substances and materials that causes water pollution include oil, plastic, tyres, tins, glass and toilet waste. These substances and materials can harm living things in water. They can harm people and animals that drink the water. Oil spills from ships pollute the seas and harm sea life. The oil does not wash off the birds’ feathers.
Birds cannot fly with oil on their feathers and they can die from cold and starvation.
People pollute water when they dump things in rivers or streams. Plastic waste such as bottles and fishing line in the ocean kills animals every year. Turtles may die after eating plastic bags which they mistake for jellyfish. Animals such as seals and penguins get tangled up in fishing line, which can injure them or cause them to drown.
Water pollution by soluble substances
Substances like soaps, fertilizers, insecticides, acids and poisonous chemicals dissolve in the water and pollute it. We often do not see these substances in water so we do not know that the water is polluted. Fertilizers and soaps lower the oxygen levels in the water.
Metals and dissolved chemicals, such as acids from factories, can pollute rivers and lakes. They are poisonous to any form of water life.
Water pollution by living germs
Getting rid of toilet waste is a problem because many people do not have proper toilets at home. People pollute water when they use rivers or streams as a toilet or if they put their toilet waste into the water. Germs in the water can make people sick with diseases such as cholera and diarrhea. People can die from these diseases.