第19期:认识细菌(19)

We all need food and water to survive. You've seen how invisible bacteria can make food inedible, but seemingly clean water can be dangerous too.

Water pollution is a growing problem that could seriously affect your health. How does water pollution affect you?

Near the beach house and there's a lot of times like stuff washes up on the beach and just stuff people throw away. I went to Mexico and you could only drink bottled water because of water pollution.

Water pollution affects me because I can't kayak in polluted water. Three-fourths of the earth's surface is covered by water.

With so much water, it's hard to believe people could have much of an effect on such a seemingly limitless resource. But water is not limitless and with every passing day, our water system is becoming more and more polluted.

When you think about pollution, you probably think about air pollution caused by cars and factories. But another kind of pollution may be more dangerous to our survival.

Water pollution. What is water pollution?

Water pollution is any change to water that has a harmful effect on people or other living things. Humans cause most pollution.

Many of our activities, agriculture, industry construction and mining produce wastes that can end up in water. Everything we make eventually gets thrown away.

What we throw away ends up in landfills and everything that ends up in a landfill eventually leeches into the ground. These materials can enter the ground water and make their way into the ocean.