1. 1.1 Chemicals in the Environment

2. Overview Chemicals in the environment Nitrogen cycle
Water, carbon dioxide, oxygen, sulfur dioxide, ammonia, nitrogen
Nitrogen cycle
Nitrogen fixation
Biotic and abiotic factors responsible
Factors that change the amount of nitrogen in the soil
Agricultural activities
Fertilizers and pesticides
Industrial processes
Natural gas and sour gas
Processes and activities that affect environmental chemicals

3. Chemicals in the Environment
Water (H2O)
Source: water bodies (e.g. oceans, lakes, etc.)
Role in the environment: hold life-supporting substances such as oxygen for organisms to breathe, required for photosynthesis and energy production
Carbon dioxide (CO2)
Source: product of respiration
Role in the environment: required for photosynthesis
Oxygen (O2)
Source: product of photosynthesis, by-product of fuel combustion, forest fires
Role in the environment: required for respiration

4. Chemicals in the Environment continued...
Sulfur dioxide (SO2)
Source: produced from fuel combustion, volcanoes, forest fires
Ammonia (NH3)
Source: nitrogen fixation from bacteria that combine ‘free’ atmospheric nitrogen with hydrogen and oxygen, lightening can also do this
Nitrogen (N2)
Source: atmosphere
Role in the environment: required by living things to produce proteins such as enzymes, and structural components

5. Nitrogen Cycle
The cycling of nitrogen through systems (e.g. the atmosphere, soil, plants, animals)
Nitrogen fixation: the process of changing free nitrogen (N2) that exists in the atmosphere to nitrogen-containing molecules, such as NH3, that can be used by organisms
Biotic factors: bacteria, nitrogen fixing plants (alfalfa, clover)
Abiotic factors: lightening

6. Nitrogen Cycle Continued
What factors change the amount of nitrogen in the soil?
Amount of plant and animal waste that returns to the soil, and the activity of decomposers that break the materials down
Water carrying nitrogen compounds away to other areas
Presence of fertilizers or nitrogen fixing plants

7. Agricultural Activities
Fertilizers
Substance that enriches soil and improves plant growth
e.g. N-P-K
Pros:
Improve plant growth from adding nutrients to the soil
Cons:
Too much fertilizer can hurt organisms
Changes the concentrations of chemicals in water bodies

8. Agricultural Activities
Pesticides
Chemicals used to kill pests (organisms that harm people, crops, or structures)
There are different types depending on the type of pest being controlled
e.g. Herbicides (plants), insecticides (insects), and fungicides (funghi)
The bertha armyworm is a major pest of canola
Pros:
Cons:
At least 50% of the world’s food production would be lost to pests if we didn’t use pesticides
Non-selective, i.e. may kill the pest and a non-pest
The pesticide for armyworms also kills bees
Some pests become resistant
Some last for long periods in the environment
e.g. DDT: banned in North America but still used in some places to control malaria-carrying mosquitos

9. Industrial Processes May release chemicals into the air
Electrical power generation
Mineral processing
Fertilizer production
A common industrial process in Alberta is natural gas processing

10. Natural Gas
Natural gas is composed of compounds such as methane, ethane, propane, and butane
Also contains nitrogen gas, carbon dioxide, hydrogen sulfide, helium, and trace metals such as mercury
During processing, raw natural gas is purified by removing contaminants such as water, carbon dioxide, and hydrogen sulfide
Processing separates its components which can be used for different things
Methane, propane, and butane are used primarily for heating
Ethane is used in plastics such as polyethylene

11. Sour Gas
Sour gas is natural gas that contains large amount of the poisonous chemical, hydrogen sulfide
Removing hydrogen sulfide produces sulfur dioxide gas and pure sulfur
Natural processing plants in Alberta have been required to restrict these emissions since the 1970s
99% of the pure sulfur recovered is used to make sulfuric acid
Sulfuric acid is used to make fertilizers, steel, synthetic fibers, and paints

12. Processes and Activities that Affect Environmental Chemicals
Pollution:
Any change in the environment that produces a condition that is harmful to living things

13. Solid Wastes:
The garbage that is collected from households, industrial plants, commercial buildings, institutions, and construction and demolition sites
Includes large items such as machinery, all the way to small items such as the caps on plastic drink bottles
Potential pollution problems: dumped in landfills, where some hazardous waste may be burned, releasing pollutants
Ways to reduce landfills:
Composting, recycling

14. Hydrocarbons + O2 → CO2 + H2O + energy
Waste Water/Sewage:
Water containing dissolved and undissolved materials from your kitchen, bathroom, and laundry
Potential pollution problems: goes directly into water bodies which then cause chemical changes that are harmful to aquatic life
Fuel Combustion:
Potential pollution problems: CO2 is a greenhouse gas that contributes to the heat absorption from the UV rays in the earth’s atmosphere
Hydrocarbons + O2 → CO2 + H2O + energy
(fossil fuels)

15. Natural gas processing: What can be done?
Industrial processes
Natural gas processing:
Potential pollution problems: sulfur dioxide emissions
What can be done?
Law to reduce the allowable emissions
Treating the SO2 before it is emitted to produce things that are less harmful
Using fossil fuels that are lower in sulfur