Transcript File

Unit C: Environmental Chemistry
Section 1: The environment is
made up of chemicals that can
support or harm living things.
First Nations people made use of
chemicals in their environment for food and
medicine. They recognized the benefits of
drinking willow bark tea.
In Europe as well, willow bark had been used since at least 400
B.C. At that time, Hippocrates, now known as the Father of
Medicine, had recommended it to treat pain and fever. The
active ingredient in willow bark was identified in the 1800s as
salicylic acid, Aspirin. The synthetic name of this chemical is
called acetylsalicylic acid.
1.1 Chemicals in the Environment
• Trees, mountains, the air we breathe, our own bodies –
everything that makes up the environment is made of
chemicals. All living things are made of chemicals and
depend on chemicals to survive.
• Not all chemicals that form the environment support
living things. For example, forest fire and volcanoes
both release large quantities of chemicals such as
carbon dioxide, sulfur dioxide, and ash. Even though
these substances are produced naturally, they can be
harmful to living things.
The Nitrogen Cycle
- Nitrogen is important for living things. 78% of air is made up of nitrogen gas, “free”
nitrogen.
- Free nitrogen cannot be used by plants, it has to be “fixed” in compounds with
other elements. This process is called nitrogen fixation.
- How do you “fix” nitrogen?
Certain bacteria do most of the nitrogen fixation in the soil. As
well, lightning also converts nitrogen in the air to nitrogen
compounds that plants can use. When the animals eat plants,
they take in the nitrogen to create proteins. Decomposers break
down these large nitrogen-containing molecules in dead
organisms and animal waste into simpler nitrogen compounds in
the soil. Sometimes the bacteria further break down this simple
nitrogen and release it into the air as “free” nitrogen.
The amount of nitrogen in the soil varies because:
- too many bacteria converting “fixed” nitrogen to “free” nitrogen.
- water could carry the nitrogen down into the soil so deep that plants do
have access to it.
- farmers remove all plants from an area.
- If soil lacks nitrogen, farmer plant nitrogen-fixing plants such as clover and
alfalfa or add fertilizers to increase the amount of nitrogen
Processes and Activities that Affect Environmental
Chemicals:
1. Nitrogen Cycle
2. Cellular Respiration:
Food + Oxygen
Carbon dioxide + Water
3. Pollution: Vehicle exhaust adds chemicals to the air.
Oxygen is needed to run an engine, but an engine gives off
carbon dioxide, carbon monoxide, nitrogen oxides, and
water vapor into the air.
4. Fertilizer: a substance that enriches soil so that plants will grow better
The three numbers on the bag represent the amount of:
1. nitrogen
2. phosphorus
3. potassium
OR, we have natural fertilizer!
Too much fertilizer can damage crops, organisms, and
may enter ponds, streams, lakes, and rivers hurting
ecosystems.
5. Pesticides, herbicides, fungicides and insecticides: These
chemicals not only hurt the organisms they are intended to hurt
but other and their surrounding environment.