Ch. 11.2 Obtaining Water Quality

Safe Drinking Water• the quality of our water is just as important as having

a steady supply of water• our drinking water must be clean and free from

harmful organisms and chemicals• to ensure this, we treat our water

Safe Drinking Water• more than 1 billion people in the world do not have

access to clean drinking water• many developing countries cannot afford to build

facilities to treat or test drinking water• in many of these areas, people wash and drink

directly from the same river water where humans and animals waste have been discharged

Factors Affecting Water Quality• contaminants – contents that are harmful to

humans, other animals, and the environment• more than likely, the water that flows out of your

faucet has flowed through your local watershed• that means any activity in your watershed that

contaminates the water can have a direct impact on the water you drink

Factors Affecting Water Quality• Three Types of Contents in Water– Biological: both visible and microscopic organisms– Chemical: dissolved substances that come from natural

processes or human activity– Physical: all materials that do not dissolve in water

Treating Groundwater Sources• groundwater must be filtered before drinking to

remove sediment and other contaminants• the water must also be tested regularly to ensure it is

safe to drink

Treating Aboveground Water Sources• we generally cannot drink the water that exists in our

freshwater systems because they contain harmful organisms and substances

• boiling water before drinking it will kill harmful organisms, but will not remove chemical or physical contaminants

• this water must be treated before being used for drinking water

• water treatment is very expensive, so it is important to keep our water sources clean so that they don’t have to be treated as intensely

The Water Treatment Plant

The Water Treatment Plant• water treatment plants are very sophisticated and

expensive• this is just an example of one such system• many different systems exist, but generally work on

the same principles

Testing Water Quality• for most of human history, we have wondered why people

could sometimes become ill or even die from drinking water• today, we have the knowledge and equipment to detect these

microscopic contaminants in our water• drinking water is tested for harmful bacteria and viruses,

chemical substances (such as lead and nitrates), and radioactive material

When you turn on the tap, where is your water coming from?