Unit C Section 1.1

Chemicals in the Environment

All living things are made of chemicals and depend on chemicals to survive.

• Many chemicals that we use can cause harm to the environment.

Willow Bark

• Contains salicylic acid

• Hippocrates- now known as the ‘Father of Medicine’- as early as 400B.C. recommended willow bark be used to treat pain and fever.

• First Nations people used willow bark tea as a medicinal drink.

Medicine from the Environment

• A synthetic version of salicylic acid- acetylsalicylic acid (ASA)- was developed by the Bayer company in 1898 and Aspirin was born.

• Other medicines derived from plants found in the environment include: Echinacea Purposa - extract from the purple coneflower to help stimulate.

More Chemicals in the Environment

• Without carbon dioxide and water, green plants could not produce sugar for food.

• Without oxygen, plants and animals could not carry out cellular respiration.

• Forest fires and volcanoes release large quantities of carbon dioxide, sulfer dioxide and ash, which can be harmful to living things.

• Many chemicals that we use can cause harm to the environment.

The Nitrogen Cycle

• Nitrogen occurs naturally in the atmosphere as Nitrogen gas (N2).

• In order for living organisms to be able to use this nitrogen, the two atoms must be separated (fixed), so they can easily combine with other elements to form usable compounds.

• Nitrogen is essential to life: all plants and animals need it to grow properly. It is the fourth most abundant element in the human body.

• Nitrogen is an essential nutrient, needed to make amino acids and other important organic compounds, but most organisms cannot use free nitrogen, which is abundant as a gas in the atmosphere.

• Gaseous nitrogen is broken apart and fixed in the process of nitrogen fixation. Some atmospheric nitrogen is fixed naturally during lightning strikes and some by industrial processes.

**78% of air is nitrogen gas

Nitrogen Fixation

• Is the process by which atmospheric nitrogen gas is converted, (fixed by lightning) so it can combine with other chemicals to form compounds that organisms can use.

• Certain types of bacteria (found in root nodules of beans, clover and alfalfa) can fix nitrogen in the soil, by separating the two nitrogen atoms, so they can combine with other elements to form compounds that can then be used by other living organisms.

Processes and Activities That Affect Environmental Chemicals

• Your body uses the chemicals in the food and the oxygen in the air in the process of cellular respiration to give you energy. One of the products released is CO2. This is a natural process.

• Human activities are not always natural and can cause pollution (any change in the environment that produces a condition that is harmful to living organisms).

• These activities release chemicals. Some of these chemicals can be broken down naturally while others can cause long-term problems.

Human Activities

Agricultural Activities

• Farmers must have an understanding of chemistry to produce crops that will give a good yield.

• Fertilizers: a substance that enriches the soil so that plants will grow better.

• 3 Numbers: (3 elements)

% Nitrogen N (1)

% Phosphorus P (2)

% Potassium K (3)

(sometimes a fourth number is present % Sulfer S

Agricultural Activities

• Pesticides (chemicals used to kill pests) Pests are organisms that harm people, crops, or structures.

• Insecticides (chemicals used to kill or control insects)

• Herbicides (chemicals used to kill or control weeds

Solid Wastes

• Solid wastes includes the garbage collected from households, industries, commercial retailers, institutions and construction or demolition sites.

• Some of these wastes can be recycled or reused, but most of it is placed in landfill sites

• A small amount is incinerated (burned)

• Some of the hazards that can occur when solid waste, containing chemicals that are harmful to the environment, are not properly disposed of include;

• Air pollution (controlled emissions - scrubbers)

• Leaching (prevented by plastic liners and compacted clay foundation at the landfill site).

Wastewater

• Sewage includes; dissolved and undissolved materials from your kitchen, bathroom, and laundry.

• Septic tank (rural areas), collects the waste from our house.

Sewage Treatment Plant (urban areas)

• A facility that treats the sewage in three levels or steps.

Primary- Physical

• filtering, sieving and settling

• waste water can be further treated with chlorine and returned to the environment as effluent. Waste materials, called sludge, can be recycled as fertilizer or landfill.

• Effluent - water that goes back into the river after being treated

Secondary- Biological

• Bacteria and micro-organisms decompose most of the remaining biodegradable waste.

Tertiary- Chemical

• Removes dissolved nitrates, phosphates and undissolved solids from the effluent

Fuel Combustion

• The burning of hydrocarbons (fossil fuels - including coal, oil and natural has - from dead plants and animals) produces large amounts of carbon dioxide and water vapour.

• Sulfer dioxides and nitrogen oxides. Traces of mercury and lead are also produces.

Industrial Processes

• The generation of electrical energy, mineral processing and fertilizer production can release harmful chemicals (sulfer dioxides and nitrogen oxides) into the air.

• Natural gas contains compounds such as methane, ethane, propane, and butane.

• If natural gas contains hydogen sulfide it is called ‘sour gas’. (Very poisonous chemical).

• If it doesn’t contain it is called ‘sweet gas’.

• Laws have been made to reduce the sulfer dioxide emissions, and the recovery of most of the pure sulfur.

• The collected sulfer is used to manufacture sulfuric acid, which is used in making fertilizers, steel, synthetic fibers and paint.