1. Potentially Harmful Substances are Spread and Concentrated by:
Chapter 3.1:
Potentially Harmful Substances are Spread and Concentrated by:
Air
Water
& Soil

2. Transport of Substances in Air
Release of the chemical at the source
Dispersion of the chemical in the atmosphere (scatter in various directions)
Deposition of the chemical in the soil or water

3. Direction and Distance substances travel in air
Determined by:
Pollutant properties
Wind speed and direction of prevailing winds
Usually West to East in Alberta
Precipitation
Substance will be deposited closer to the source if carried to the ground by rain or snow

4. Issues:
Substances can travel 1000s of Kilometers, and it’s often impossible to find the source
Creates conflict when substances cross international boarders

5. Transport of Substances in Groundwater
Water soaks into soil :
Near the surface the soil contains both air and water
The deeper you go, you find only water = GROUNDWATER
The top of the GROUNDWATER zone is the water table where we get our well water

6. Groundwater Movement
Groundwater can travel in all directions, but it travels much slower that rivers and streams
Because of slow movement, some contaminants cannot be rid of quickly
Can become concentrated over time
Creates a problem if we need this water

7. Factors that can effect Groundwater movement:
Connection of pores in soil
Too tightly packed = No soil pore connections = extremely slow ground water movement
Permeable soil has interconnected pores
Pollutants will travel further in Groundwater running through permeable soil
Groundwater pollutants occur naturally & as a result of human activity

8. Transport of Substances in Surface Water
Substances can enter Surface water systems by air, groundwater, runoff from agricultural fields, sewage, etc.
If substances dissolve they can travel great distances
If NOT, they become attached to solids, sink, and become concentrated

9. They can build up at the bottom of lakes and rivers

10. Walkerton, Ontario
Water supply became contaminated with E. coli bacteria from agricultural runoff into an adjacent well
Causing bloody diarrhea, gastrointestinal infections and more
With drinking water contaminated: 7 people died and about half the population fell ill (2500)

11. Transport of Substances in Soil
Water hits soil  Moves downward  Dissolves substances in soil  Carries dissolved substances with it (leachate)
Once it hits clay, it stops (impermeable)
Organic molecules can also absorb chemicals and slow movement
Naturally occurring substances can also neutralize chemicals - limestone

12. Page Check and Reflect.
Exclude question #3.