1. Part Two The Human Impact on Water
Life Science
Part Two
The Human Impact on Water

2. How is Water Quality Measured?
Water quality is measured by testing levels of
Dissolved solids
pH level
Dissolved oxygen
Turbidity
Microbial load
Open your workbook to page 212 and using the chart in the bottom half of
the page write “what it is” next to each term above
Quality standards depend on the planned use of the water.
Drinking water needs to meet much stricter quality standards than environmental lakes and rivers do.

3. How is Water Treated for Human Use?
Screens take out the large debris
Chemicals are added to make suspended materials stick together
Particles drop out of the water through a process called flocculation
Chlorine is added to kill microbes
Air is bubbled through the water
Water is now suitable to drink. It is referred to as potable.

4. Who Monitors and Protects Our Water Supply?
The Environmental Protection Agency (EPA)
Enforces the Safe Drinking Water Act.
This federal law ensures safe drinking water for people in the United States.
Sets the standards for drinking water
Tests the water

5. How Does Water Get to the Faucet?
Piped water supply systems
deliver water over
great distances.

6. What Threatens Our Water Supply?
Demand that is greater than supply
Droughts
Leaking water pipes
Before the water company installed a new water main down the middle of Lincoln Way, water main leaks occurred frequently.