1. Pollution & Toxins Pollutant
Substance in the environment that produces a condition that is harmful to living things
Toxin
Substances that produce serious health problems or death

2. How can chemicals be introduced into the environment?
1. Agriculture
Fertilizer
Pesticides
2. Wastes
Solid
Waste-water

3. 3. Fuel combustion
Fossil fuels
When burned – release CO2 and H2O
4. Industry

4. Effects of Chemicals on Environment
Biological magnification
Increase in concentration of a substance as it moves up the food chain / web
Eg. DDT

8. Measuring Toxicity
LD50
Amount used to compare the effects of different toxins
LD = lethal dose
50 = 50%
Amount of a substance that causes 50% of a group of test organisms to die if given a specific dose
The lower the LD50
The less needed to kill test organisms
The more toxic the substance
Ex. LD50 of 150 is more toxic than LD50 of 200

9. Concentration Amount of a substance in a given volume Ways to measure
g / L %
PPM (parts per million)
mg / L
1 part substance in parts of H2O
1 mg substance / 1 L H2O
1 ppm = 1 drop of food coloring in a bathtub half full of water

10. How to calculate ppm:
Eg. If you add 0.1 ml of DDT to 2000 ml of water, what is the concentration in ppm?
Set up an equivalent ratio
0.1ml DDT x =
2000ml water ml
0.1 ( ) = 2000x
= 2000x
x = 50

11. PPB (parts per billion)
1 ppb = 1 drop of food coloring in a swimming pool
PPT (parts per trillion)
1 ppt = 1 drop of food coloring in 1000 swimming pools

13. Disposal of Solid Wastes
Incineration
Burn very high temperatures
Emissions may contribute to air pollution
Dump
Open hole in the ground where trash is buried
Substances are able to leach (leak) into surrounding soil and ground water

14. Removal of materials by dissolving them away from solids
Leaching
Removal of materials by dissolving them away from solids
Leachate (liquid that dissolves and carries substances) can contaminate water supplies
Landfill
Carefully designed structure built into/on top of ground
Trash is isolated from the surrounding environment by the use of a bottom liner and daily coverings of soil
Prevents leaching

16. Disposal of Liquid Wastes
Septic tank
Underground container where bacteria break down organic materials
Often used when households are not connected to municipal sewer (eg. acreages, farms)
Storm sewers
Water directly enters rivers or lakes without treatment or cleaning

17. Sewage treatment plant
Treat wastewater with several steps including filtration, chemical treatment and biological treatment
Treated wastewater = effluent
Can be released into rivers or lakes
May still contain N, P and other substances not removed by filtration