Water Quality Flashcards
Drinking water needs to be…
Good quality
Water must be free of [ ] and [ ] to drink it.
Poisonous salts (Phosphates and Nitrates) Harmful Microbes
Why are harmful microbes bad for drinking?
Can cause disease such as cholera and dysentery
Most of our drinking water comes from…
Reservoirs
Describe reservoirs and where the water comes from.
Water flows into reservoirs from rivers and groundwater. Companies choose to build reservoirs where there’s a good supply of clean water. Government agencies keep a close eye on pollution in reservoirs, rivers and groundwater.
Describe how water is treated. (4 steps)
1) Water passes through a mesh screen to remove big bits
2) Chemicals are added to make solids and microbes stick together and fall to the bottom.
3) The water is filtered through the gravel beds to remove all the solids.
4) Water is chlorinated to kill off any harmful microbes left.
What do commercial filters do?
They contain carbon or silver to remove substances from their tap water. Carbon in the filters removes chlorine taste and silver is supposed to kill bugs.
What do water softeners contain? In which areas would you want a water softener?
Iron exchange resins
People in hard water areas
What is totally pure water?
Water with nothing dissolved in it
How can totally pure water be produced?
Through distillation - boiling water to make steam and condensing the steam.
Why isn’t tap water distilled?
Too expensive - bags of energy would be needed to boil the water
Why is fluorine added to water in some parts of the country?
Helps reduce tooth decay.
Why is chlorine added to water?
Prevent disease
Some studies have linked adding chlorine to water with an increase in certain [ ]. Chlorine can react with other [ ] in water to produce [ ].
Cancers
Natural substances
Toxic by-products
In high doses fluoride can cause [ ] and [ ] in humans, so some people believe that [ ].
Cancer
Bone problems
Fluoride shouldn’t be added to drinking water
