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Environmental Chemistry

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Nicole Abrenilla

on 11 June 2013

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Transcript of Environmental Chemistry


Unit C
Environmental
Chemistry
1.1 Chemicals in the Environment
Chemicals in the Environment
What you need to know:
1. Chemicals in the Environment
2. The Nitrogen Cycle
3. Natural Process vs. Human Activities
(a) Pollution
(b) List of Human Activities
The Nitrogen Cycle
After Nitrogen Fixation Occurs..
1.0
1.2 Acids and Bases
What you need to know:
1. pH Scale
2. Acid/Neutral/Base
3. Measuring pH
4. Neutralization
5. Neutralizing the Effects of Acid Rain
pH Scale
Acid/Neutral/Base
Acid
Neutral
Base
Measuring pH
Neutralization
Neutralizing the Effects of Acid Rain
1.3 Common Substances Essential
to Living Things
What you need to know:
1. Types of Organic Molecules
a) Carbohydrates
b) Lipids
c) Proteins and Amino Acids
d) Nucleic Acids
Carbohydrates
Lipids
Proteins and Amino Acids
Nucleic Acids
1.4 How Organisms Take
in Substances
What you need to know:
1. Uptake Nutrients by Plants
(a) Passive Transport (Diffusion and Osmosis)
(b) Active Transport
2. Uptake of Nutrients ad Digestion
(a) Ingestion and Digestion
(b) Hydrolysis
3. Taking in Nutrients in Different Environments
Passive Transport (Diffusion and Osmosis)
Active Transport
Ingestion and Digestion
Ingestion
Mechanical Digestion
Chemical Digestion
Hydrolysis
Organisms inhabit almost all parts of Earth - from the icy Arctic to the tropical jungles, and from mountain slopes to deep under the ocean. Where organisms live effects how and when they can obtain nutrients.
Taking in Nutrients in Different Environments
2.0
3.0
2.1 Monitoring Water
Quality
What you need to know:
1. How is water quality determined?
2. Biological Indicators
3. Aquatic Environments
4. Chemical Factors That Effect Organisms
5. Measuring Chemicals in the Environment
All living things are made up of chemicals and need chemicals to survive. Some chemicals however do not support living things.
Human Activity can cause chemical changes in the environment from the things we rely on.
All chemical compounds are made up of elements. Elements form chemical compounds that are used and reused by living things.
The Nitrogen Cycle is important for all living things. It makes up 78% of the air as "free" nitrogen in the form of nitrogen gas (N2)
Plants require nitrogen but can't use the "free" nitrogen but only when it is combined with oxygen and hydrogen compounds.
Nitrogen Fixation
Nitrogen fixation is the process of changing free nitrogen so that the nitrogen atoms can combine with other elements to form compounds. Certain types of bacteria do most of the nitrogen fixation in the soil. These bacteria can separate two nitrogen atoms so they can form needed compounds.
Plants use the nitrogen containing compounds
Animals then eat the plants. Their bodies use the nitrogen in the compounds to make more complex substances such as proteins.
Decomposers break down these large nitrogen containing molecules in dead organisms and animal waste into simpler nitrogen compounds in the soil.
Natural Processes vs. Human Activities
Pollution
Human Activities
Agricultural
Activities
Fertilizers
Pesticides
Disposing of Solid Waste
Sanitary Landfills
Treating Waste Water
Sewage
Effluent
Driving Vehicles
Industrial Processes
Any change in the environment that produces a condition that is harmful to living things.
Example:
Smog caused by vehicle exhaust emissions
Forest fire emissions (caused by hot weather)
Human activities release chemicals into the air, water and soil everyday through:
Agricultural Activities
Disposing of Solid Wastes
Treating Waste Water
Driving Vehicles
Industrial Processes
Farmers need to have an understanding of chemistry to produce good crops.
They need to know:
Which chemicals to add soil to improve plant growth
That chemicals to treat plants with to protect them from pests
A substance, containing chemical nutrients,which
They come from natural or synthetic sources
Added to soil to enhance plant growth but must be applied carefully as too much can damage an organism
If fertilizers enter ponds, lakes or rivers, they may damage those ecosystems by changing the concentration of chemicals
Chemicals used to kill pests - an organism that harm people, crops, or structures.
Herbicides - kill or control weeds
Insecticides - kill or control insects
Fungicides - kill fungi
Pesticides can create problems:
some are not selective (they kill both pests and non-pests)
they stay in the environment for a long time some pests become resistant to pesticides (new ones must be developed)
Chemicals may be introduced into the environment when we dispose of solid waste.
Includes garbage from:
households
industrial plants
commercial buildings
institutions
construction and demolition sites
Some can be recycled or reused but most is put into landfills or burnt in incinerators - emissions may contribute to air pollution
Is a special site to prevent waste (chemical) from moving into the soil and leaching into the groundwater.
They use plastic liners and compacted clay to prevent solutions from entering soil and groundwater.
Sewage is the waste water containing dissolved and un-dissolved material from everyday household water use.
It moves through pipes into either:
Septic Tank (rural community)
An underground container which has bacteria that helps to break down solid and liquid waste.
Sewage Treatment Plant (urban community)
A facility that treats waste water before it is released back into the water supply.
A treated waste water that is returned to the water supply (rivers,lakes) It may contain nitrogen or phosphorus from the breakdown of sewage during treatment. If municipal sewage systems can't handle a large quantity of rain water from street drains, they go through.
Storm Sewers:
Large underground pipes that carry excess surface water (runoff) directly into rivers or lakes. This water contains chemicals washed off the street such as oil or other fluids that have leaked from vehicles and salt from snow clearing.
Fuel combustion involves the burning of fossil fuels - coal, oil and natural gas. When fossil fuels are burned in homes, vehicles and industrial plants, they release large amounts of carbon dioxide and water vapor. They may also release pollutants such as sulfur dioxide, nitrogen oxides and traces of mercury and lead into the air.
Electrical Power Generation
Mineral Processing
Fertilizer Production
Natural Gas Processing - common in Alberta
It indicates how acidic or basic a substance is.
It is a measure of the concentration of hydrogen ions in a solution.
Each increment is 10x greater than the one next to it.
Compound that dissolves in water to form a solution with a pH < 7
Examples:
Vinegar - acetic acid
Lemon Juice - citric acid
Vitamin C - ascorbic acid
Neither acid or base
pH = 7
A compound that dissolves in water to form a solution with a pH > 7
Acids
taste sour
react with metal
do not feel slippery
Base
taste bitter
do not react with metal
feel slippery
You can use a pH meter or an acid-base indicator.
A pH meter consists of a probe attached to a meter. To test the fluid, you submerge the tip of the probe into the solution and the meter indicates the pH reading.
Acid-base indicators are substances that change color when they are placed in solution.
Litmus Paper
- In acid, blue litmus paper turns red
- In base, red litmus paper turns blue
Universal Indicator: mixture of several indicators that change the color as the acidity changes. To determine the pH, you need to use a color chart.
When acids and bases react together, acidic and basic properties disappear. This process is called neutralization.
Neutralization reactions produce:
acid + base ----> water + salt
Neutralizing the Effects of Acid Rain
Acidic lakes are sometimes treated with lime (calcium hydroxide) to neutralize them. A chemical reaction takes place between the lime, which is base, and the sulfuric acid of the lake's water.

This Process neutralizes the acidity of the lake water.
Calcium Hydroxide + Calcium Sulfate (a salt) + water
Organic compounds made up of atoms of...
Carbon, Hydrogen, and Oxygen
Found In:
pasta, rice, potatoes, fruit and bread
They form simple molecules such as sugar or large, complex molecules such as starch, cellulose and glycogen
Lipids are organic compounds that are made up of many atoms of..
Carbon, Hydrogen and Oxygen
Found In:
fats, oils, and waxes
They are organic compounds made up of units of amino acids.
Amino acids are organic compounds made up of atoms of...
Carbon, Hydrogen, Oxygen and Nitrogen
Largest and most complicated molecules.
All cells contain two important nucleic acids:
1. DNA
2. RNA
Made up of phosphates, a simple sugar-ribose and nitrogen containing molecules.
Found In:
All cells
Nutrients enter the roots of plants either passively or actively.
Passive Transport:
Diffusion: the natural movement of particles
Osmosis: the natural movement of water
Both move from an area of....
High concentration to an area of low concentration until a state of equilibrium has been reached.
NO ENERGY REQUIRED = PASSIVE TRANSPORT
Diffusion of water or solutes can take place across a cell membrane if there is a difference between the concentrations of water or solutes on either side of the membrane.
Cell membrane acts as a "gate keeper" trying to maintain equilibrium.
Cell membrane requires energy input because particles move against the concentration gradient...
Movement from low to high concentration.
Carrier proteins work as a pump to move molecules across membrane. This is difficult and requires energy. Plants use energy to transport nitrogen, phosphorous, sulfur, and potassium into their roots. The nutrients move from an area of concentration (soil) to one of higher concentration (roots)
Humans and other animals obtain the 25 elements our bodies need for normal growth and function from the air we breathe and food we eat.
The process by which we take food into our bodies.
Chewing food
The process of digesting food in your stomach with the help of enzymes
The chemical breakdown of large organic molecules.
A substance that is broken down my hydrolysis has been hydrolyzed.
Example: When you eat potatoes, the large starch molecules are hydrolyzed into double sugars called maltose, and then into simple sugars called glucose.
Maltose + Water ----> Glucose
Substrate
The earthy material in which an organism lives, or the surface area or medium on which an organism grows or is attached.
How is Water Quality Determined?
Microbiological Indicators
Aquatic Invertebrates and Vertebrates
Aquatic Environments
Chemical Factors That Affect Organisms
Dissolved Oxygen
Plant Nutrients such as Nitrogen and Phosphorus
Acidity
Heavy Metals
Pesticides
How Are Chemicals In The Environment Measured?
LD50
Measuring Chemicals in the Environment
2.2 Monitoring Air Quality
What You Need to Know:
1. What is Air Made up of?
2. How Can Air Quality be determined?
3.Sulfur Dioxide
4. Nitrogen Oxides
5. Carbon Monoxide
6. Ground Level Ozone
2.3 Monitoring the Environment
Biological Indicators
Water quality is determined according to what the water is used for.
Both Provincial and federal government set guidelines for water quality in five categories of water use:
1. Human drinking water
2. Recreation such as swimming
3. Livestock drinking water
4. Irrigation
5. Protection of aquatic life
Drinking water needed to be treated regularly for microorganisms
Certain microorganisms are considered harmful. For example, E.Coli
To reduce the numbers of harmful microorganisms, water can be: chemically treated, heated and/or filtered.
The presence or absence of certain invertebrates and vertebrates tells us about the water chemistry.
For example, lowered pH reduces insect pollutions.
Toxins become more concentrated as they move up the food chain. For example, fish have elevated levels of toxins.
If the pH of the water in an aquatic environment is below 5.0, you will not find many fish there. Some insects are also very sensitive to acidic environments and environments that have little dissolved oxygen. The diversity of all organisms decreases as acidity increases and dissolved oxygen decreases.
Dissolved oxygen
Plant nutrients such as nitrogen and phosphorous
Acidity
Pesticides
Heavy metals
The level of dissolved oxygen in water depends on:
temperature
turbulence due to wind or the speed of moving water
the amount of photosynthesis by plants and algae in water
the number of organisms using up the oxygen
AS dissolved oxygen levels decrease, the diversity of living organisms decrease.
5mg/L or 5 ppm of dissolved oxygen will support most organisms that live in lakes and streams.
One factor that can affect dissolved oxygen is an increase in phosphorus and nitrogen in the water. Phosphorus and nitrogen are important to all living things, but too high a concentration in water can cause problems. Large amounts of phosphorus and nitrogen can enter water systems in different ways. Sewage outfalls and runoff from fertilized fields are two possible sources. Higher concentration of these nutrients in water cause increased growth of algae and green plants. As more algae ans plants grow, more die. This dead organic matter becomes food for bacteria increase in number and use up the dissolved oxygen in the water. When the dissolved oxygen content decrease, many fish and aquatic insects cannot survive.
Our body can be compared to a vehicle. We give it food as "fuel" and air rich in oxygen. It uses the chemicals in the food and the oxygen in the air in the process of cellular respiration to give us energy. One of the products you release in this process is carbon dioxide. Cellular respiration and the nitrogen cycle are natural processes. Driving a car is a human activity where chemicals are released into the environment. Both natural processes and human activity may change the chemicals in the environment.
"LD" stands for "lethal dose" 50 = represents 50% of a group of test animals to die if they are given a specified dies if the substance all at once.

LD50 is the standard measure of toxicity of a substance.
Examples:
The LD50 for alcohol is 10.3g/kg, therefore, it would take 824g of alcohol to kill 50% of all humans that have a mass of 80kg.
The LD50 of nicotine for most people is in one cigarette!
Lead = 11.0mg/kg
Caffeine = 192mg/kg
Nicotine = 53.0mg/kg
Cocaine = 95.1mg/kg
One part per million means that one unit of an element of chemical can be found in one million units of solution.
Things to remember:
Ppm is expressed in mL
Remember hot to convert values!
General Formula:
Volume of Solute
Volume of Solvent
=
x
1,000,000
Example:
A student puts 0.53 mL of food coloring into water to make 1000 mL of solution. What is the ppm of the food coloring in the water?
V.solute = 0.53 mL (of food coloring)
V.solvent = 1000 mL (of solution)
0.53 mL
1000 mL
=
x
1,000,000
x 1,000,00
1,000,000 x
x = 530 ppm
Air is made up of...
Mainly nitrogen (78%) and oxygen (21%) with some argon less than (1%) carbon dioxide (0.03%) and traces of hydrogen and neon.
Air quality can be determined in two ways...
1. By measuring the levels of pollutants in the air. < better indicator
2. By estimating the amount of emissions from pollution sources.
Sulfur Dioxide
Sulfur Dioxide is a major air pollutant that forms both smog and acid rain. It can affect your respiratory system (throat and lungs) and irritate your eyes. It forms when oxygen combines with sulfur and by burning fuels such as coal, oil, and natural gases. The major source of sulfur dioxide is industrial processes, oil and gas industry. To reduce sulfur dioxide emissions, industrial and electrical generating plants use "scrubbers." Scrubbers use limestone to convert the pollutant sulfur dioxide to a useful product.
Nitrogen Oxides
Nitrogen oxides are major air pollutants that form both smog and acid rain. They affect the respiratory system and eyes. Nitrogen oxides form from combustion in vehicles and by combustion in generating plants and some industrial processes such as oil refining. The nitrogen formed by burning fuels first combines with oxygen to form nitrogen monoxide gas. This then combines with oxygen in the atmosphere to form nitrogen dioxide, a brownish gas.
Carbon Monoxide
Ground Level Ozone
What you need to know:
1. Carbon Dioxide as a Greenhouse Gas
2. The Greenhouse Effect
3. The Enhanced Greenhouse Effect
4. Global Warming
5. The Ozone Layer
6. The Role of Chlorofluorocarbons
Carbon Dioxide as a Greenhouse Gas
The Greenhouse Effect
The Enhanced Greenhouse Effect
Global Warming
The Ozone Layer
The Role of Chlorofluorocarbons
3.1 Transport of Materials Through Air, Soil, and Water
What you need to know:
1. Transport in Air
2. Transport in Groundwater
3. Transport in Surface Water
4. Transport in Soil
5. Transport of Hydrocarbons in Soil
Transport in Air
Transport in Groundwater
Transport in Surface Water
Transport in Soil
Transport of Hydrocarbons in Soil
3.2 Changing the Concentration of Harmful Chemicals in the Environment
What you need to know:
1. Changing the Concentration
2. Dispersion
3. Dilution
4. Biodegradation
(a) Role of Bacteria
(b) Factors Affecting Biodegration
5. Phytoremediation
6. Photolysis
Changing the Concentration
Dispersion
Dilution
Biodegradation
(a) Role of Bacteria
(b) Factors Affecting Biodegration
Phytoremediation
Photolysis
3.3 Hazardous Chemicals Affect Living Things
What You Need to Know:
1. Biomagnification
2. Oil Spills impact on.....
(a) Environment
(b) Plants and Animals
(c) Clean-up
Biomagnification
Oil Spills impact on.....
(a) Environment
(b) Plants and Animals
(c) Clean-up
3.4 Hazardous Household Chemicals
What you need to know:
1. Household Chemical Examples
2. Government Regulations
(a) Labeling - WHMIS
(b) MSDS
3. New Product Registration
4. Transporting
5. Disposal
6. Hazardous Waste Collection Sites
Household Chemical Examples
Government Regulations
(a) Labeling - WHMIS
(b) MSDS
New Product Registration
Transporting
Disposal
Hazardous Waste Collection Sites
Unit C: Environmental
Chemistry

By: Nicole Abrenilla
9-1
Full transcript