What’s in the Water?

We rely on water just as much as we rely on food. And we take it for granted that the water in our homes is pure and safe to drink. Mostly it is, but not always. And there are many places in the world where drinking water can be as contaminated as some of the foods we’ve looked at.

Protists

Many of the microscopic life-forms that find their way into drinking water are protists. Protists are usually singlecelled microorganisms that live in water or damp places. You will remember we read about parasites that can get into our bodies from food and live inside us. Some protists can become parasites inside us if we drink the water that contains them.



The light blue circle is an amoeba called Entamoeba histolytica. It can get into people’s bodies from drinking water

Amoebas

Amoebas are one kind of protist. Even though they consist of just one cell and look like a shapeless blob, amoebas can move around and even catch food to eat! Like bacteria, amoebas can reproduce just by dividing themselves.

Giardia

Giardia lamblia is another protist that infects people’s intestines. It can exist in water in a dormant (inactive) stage called a cyst. When it gets into your body, it becomes an active parasite and can give you a nasty illness called giardiasis. Infections from Giardia can last for a long time.



The Giardia lamblia protist has several flagella— the whip-like tails it uses to move around.