Unit 3: Environmental Chemistry
Lesson 1: Nutrients
-Your
body is made up of chemicals, which you
obtain from the food you eat
-The process of digestion breaks down the
chemicals into small, soluble molecules, which
pass through membranes into the blood vessels.
-These NUTRIENTS circulate through your body
to the cells where they are used for energy, growth,
and cell repair.
- Nutrients can be divided into two major groups:
ORGANIC and INORGANIC.
- Organic nutrients contain carbon and are
classed as CARBOHYDRATES, PROTEINS,
LIPIDS, and VITAMINS.
-Inorganic nutrients are referred to as
MINERALS or ELEMENTS – iron, calcium, zinc etc.
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ORGANIC
MOLECULE
ROLE
Carbohydrates Energy for
metabolism
Proteins
Lipids
Structural
molecule for
body and helps
chemical
reactions
Storage of
unused
chemical
energy
SOURCE
Rice, grains,
potatoes, fruits
Meat, eggs,
legumes, nuts,
dairy products
Vegetable oils,
nut oils, some
dairy products
- Green plants form many of the organic compounds.
- MICROMINERALS or TRACE ELEMENTS means the
body needs less than 100 mg/day.
-
Macromineral -means the body needs 100 mg/day
or more.
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- These minerals are essential components in
ENZYMES, which are special protein molecules that
regulate chemical reactions in living organisms.
- Vitamins are large organic molecules that help the
enzymes function and that the body CANNOT make
itself
- Some of the Earth's elements are examples of
chemicals the body needs and 16 of the naturally
occurring elements occur in all living organisms.
- Green plants require 18 different elements.
- Humans require 22 different elements.
- In order to remain healthy, these elements must
be in balance.
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Lesson 2: Fertilizers
- Plants need three essential elements to grow and
reproduce:
1. NITROGEN: for stem and leaf development
2. PHOSPHORUS: for seed germination, root
development
3. POTASSIUM: for flower and fruit
development
- On all commercially prepared fertilizer bags,
these three elements, in the above order are shown
by the use of a three-part number (21 - 7 – 7 –
gives percentage of each)
- With the use of artificial fertilizers and other
human activities, crop production has doubled
worldwide since the 1950's.
- Land barely suitable for farming can now be used
with the use of fertilizers, irrigation, and the use of
pesticides.
- Pro: food production increases
- Con: environmental impacts
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Pesticides
- Pesticides are used to control "pests".
- There are three specific types of pest species:
1. HERBICIDES: control weeds.
2.
INSECTICIDES: control insects.
3. FUNGICIDES: control fungus pests
- The chemical DDT is an example of an
insecticide, which kills the insects it comes in
contact with. Unfortunately it moves up through
the food chain.
- BIOMAGNIFICATION: moving from
producers to primary consumers to secondary
consumers and accumulating in greater and greater
amounts in the organisms higher in the food chain
- One major problem with pesticides is pesticide
resistance - the ability of an organism to develop a
resistance to a toxic chemical.
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Lesson 3: Acids
& Bases
Acids
- Taste sour
- Soluble in water
- React with metals to produce hydrogen gas
Bases
-
Taste bitter
Soluble in water
Feel slippery
React with acids
Neutrals
- Neither acidic or basic
- Ex. water
Indicators and the pH scale
- An indicator is a chemical that changes a
different color in an acid vs a base
- Litmus paper is a common indicator
used in schools.
- It turns red in acids and blue in bases
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- pH is a scale used to indicate the strength
of the acid or base
- pH scale ranges from 0 – 14
- pH of 7 is neutral – pure water
- pH less than 7 – acid
- pH greater than 7 – base
0
acid
7
(see p. 198)
base
14
- Other indicators include: phenolphthalein,
bromothymol blue, and methyl orange.
Neutralization Reaction
When an acid is mixed with a base, the products are
water and a salt - this is called neutralization.
Ex. Stomach acid has a pH of 2. Antacids are
mild bases that react with excess acid and
neutralize it.
Acid + Base -----> Water + Salt
e.g.
Hydrochloric acid + sodium hydroxide ----> water + sodium chloride
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Lesson 4:
Acid Rain
- Usual pH of rain is 5.6
- Acid rain has a pH lower than 5.6
(the lower the pH the more acidic)
- Sulphur, nitrogen, and carbon oxides
combine with water vapor in the air to
produce acids.
SULPHUR DIOXIDE (S02)
- Clear, colorless, highly corrosive gas
smells like rotten eggs
- Coal contains more sulphur than oil and
much more than natural gas
Sulphur + oxygen ---> sulphur dioxide
- Sulphur dioxide combines with water to
make acid rain (sulfuric acid).
NITROGEN DIOXIDE (N02)
- Yellowish, brown gas responsible for smog.
- Nitrogen oxide combines with water to produce acid
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rain (nitric acid)
HYDROCARBONS
Carbon and hydrogen compounds create carbonic acid
Carbon dioxide + water  carbonic acid
Acid Rain Causes
- Changes in soil and water that reduce soil fertility.
- Leaching of toxic chemicals such as mercury from the soil
into water
- Corrosion of metal surfaces.
- Eats stone statues and limestone buildings.
Acid Shock
- Spring melting releases large amounts of acids into rivers,
lakes, etc. for a short period. Unfortunately females have
difficulty laying eggs in acidic water. Therefore, no young
are born and the fish population eventually dies out.
Controlling Acid Rain Effects
- To neutralize the acid in lakes calcium carbonate is added
- Limestone is a major source of calcium carbonate
- Limestone will neutralize acid rain - granite does not.
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- Areas where there is limestone have less destruction due to acid
rain.
- The process of adding calcium carbonate to the
environment is called LIMING or ACID-BASE
NEUTRALIZATION.
Controlling Emissions
CATALYTIC CONVERTERS
- Are devices, which remove oxides before they enter the air.
- Aids the formation of carbon dioxide and water from
hydrocarbons thus reducing the amount of carbon monoxide
and nitrogen oxides produced.
"SCRUBBERS"
- Are devices that industrial factories and power
plants, that burn coal, use to remove oxides.
They use sorbents - substances that absorb or capture
oxides.
COBRA (Copper Oxide Bed Regenerable Application)
uses beads of aluminum oxide with copper to remove
sulphur dioxide gas - the beads can be reused.
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Lesson 5:
Concentrations
POLLUTION is material or form of energy added to
the environment that will cause harm to a living
organism.
- The harm may not be immediate depending on
concentration
- Concentration of a harmful substance is usually
given in (ppm) parts per million, (ppm is the same
as # of mg/kg).
Ex. There is 7 mg of cholesterol in 125 g of yogurt.
What is the concentration of cholesterol in ppm.
Answer: We know that 1ppm is equal to 1mg/kg.
Therefore we have to change the mass of the
yogurt to kg.
125 = 0.125 kg
1000
7 mg cholesterol = 56 mg/kg
0.125 kg yogurt
- Since mg/kg is equivalent to ppm, there is 56 ppm
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of cholesterol in yogurt.
- TOXICITY
is the ability of a chemical to
cause harm to an organism.
- ACUTE TOXICITY serious symptoms
appear after only one exposure to chemical.
- CHRONIC TOXICITY symptoms appear
when chemical accumulates to a specific level
after many exposures over time (lead)
- It is not easy to establish the level at which a
substance is toxic due to the differences in body
mass, metabolism, and lifestyles.
- LETHAL DOSE 50 - refers to the dose of a
chemical that will kill 50% of the population to
which it is applied.
- Since not all individuals or species react the same
to a particular chemical, establishing risk is often
difficult.
- A dose that kills one may only cause mild
discomfort in another
- Toxicity depends on how it enters the body
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- Published toxicity levels on humans are guesses
based on assumptions
- Every chemical has the potential to be harmful,
depending on dose, our susceptibility, and how it
reacts with other chemicals. The evaluation of risks
and benefits of any chemical form the basis of how
chemical use is regulated.
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Lesson 6:
Monitoring Waste
- Waste can be divided into two categories:
1. NON-PERSISTENT or BIODEGRADABLE
- Waste that can be broken down into simple
non-polluting compounds (fertilizers, food).
2. PERSISTENT or NON-BIODEGRADABLE
- Accumulate and break down very slowly or not at
all. The damage done by these pollutants is
irreversible (Pesticides, petroleum products).
WATER QUALITY
- Cloudy water or turbid contains un-dissolved
solids suspended in it. Suspended solids block
sunlight, which reduces the ability of plants and
algae to carry on photosynthesis.
Photosynthesis produces oxygen, so there will
be insufficient oxygen for other organisms.
Measuring Phosphates and Nitrates
- Excessive amounts may cause algae to form a
dense growth or "algal bloom". Once the
excess phosphates and nitrates are used up
the algae dies and the decomposers take over
and reduce oxygen levels.
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Measuring Dissolved Oxygen
- Measured in milligrams per liter (mg/L) or parts
per million (ppm). Most organisms need a minimum
of 5.0 mg/L of oxygen
- Amount of oxygen in water depends on 2 main
factors:
1. Abiotic Factors
- Non-living parts of the environment including
temperature of water and whether it is calm or turbid.
2. Biotic Factors
- Living parts of the environment
- Organisms such as fish, snails, bacteria and fungi use
oxygen in water. If there are a large amount of
biodegradable material the decomposers multiply and use
up the oxygen.
Biological Indicators
- Most species of organisms cannot live in polluted water,
but some species of worms and insect larvae (young) thrive
in polluted conditions. These organisms are referred to as
BIOLOGICAL INDICATORS.
- The most useful organisms for a biological indicator of
water quality are the MACRO-INVERTEBRATES 17
organisms visible to the unaided eye and have no backbone.
- A survey of the number and type of macro-invertebrates
found in a body of water can provide a general indication of
whether pollutants are present or not.
* Organisms that are representative of poor water
quality may be found in any type of water.
* Organisms representative of good water quality are
found only in water of good quality.
POINT SOURCE - specific location where pollutants enter the
environment - easy to monitor and control. Ex. Drainpipes,
smokestacks.
NON-POINT SOURCE - are often separated both in time and
location from the source - much harder to control because the
pollutants become highly dispersed as they travel. Ex. Feedlots,
construction sites, run off from fertilized fields.
Assignment 6: p. 235 # 1- 4 (copy questions)
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Lesson 7: Blowing
in the Wind
Human beings produce over 1000 billion kg of solid
waste every year, which must be removed and stored,
but “Not In My Back Yard”
In the past, natural sources such as forest fires and
volcanic eruptions introduced the majority of pollutants
into the air.
While this is still true for most of the southern
hemisphere, human activities are the biggest source in
the northern hemisphere.
Due to the wind patterns in the northern hemisphere,
airborne particles and gas pollutants tend to concentrate
at higher latitudes and are eventually washed out of the
atmosphere by rain and snow.
Chlorofluorocarbons (CFC's) are responsible for the
depletion of the Ozone layer
- CFC's were used as:
- An agent in forming Styrofoam
- Propellants in aerosol cans
- Coolants in air conditioners and refrigerators
- It was cheap, non-toxic, and stable
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- Unfortunately, ultraviolet light reacts with the CFC
molecules to produce chloride ions
- Chloride ions act as a catalyst for the breakdown of
ozone (03) gas to normal oxygen gas (02).
Ozone is needed in the stratosphere where it prevents
ultraviolet light from reaching biological organisms at
the surface, which can experience cell damage (UV
Index).
Water Pollution
- Pollutants reach water (lakes, streams, rivers) through
ground water and through the air from burning fossil fuels.
- Liquids and solid waste is carried away from homes as
sewage.
- Many rural areas have large tanks near homes called septic
tanks.
- Sewage treatment plants treat domestic waste, industrial
waste and water from street drains.
- Partially purified water, called EFFLUENT, runs into
rivers, lakes, or oceans.
Sewage Treatment - Three Stages
1. Primary - physical processes (filtering or sieving
followed by settling)
- Waste material settled out is SLUDGE.
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2. Secondary - removes much of the organic
compounds by bacterial decomposition. The resulting
sludge is removed, and the remaining liquid effluent is
treated with chlorine or exposed to UV light.
3. Tertiary - Effluent is now percolated through
marsh or lagoon to remove any nitrates and
phosphates that remain (plants growing here will use
these compounds).
Ground Water
- Water, which filters down through soil and fills the spaces
between particles of rock and soil and the cracks and fractures in
underlying rock - moves towards rivers, lakes, or the sea.
- Water can move between 15 meters per year, to a few
centimeters per century.
Aquifers
- An area where permeable material can produce useful amounts of
water when a well is drilled into them - water naturally filters
through soil. Contamination can easily result from toxic herbicides,
pesticides, and solvents in industry and agriculture.
Hazardous Wastes
- Any discarded material that contains substances that are known to
be poisonous, toxic, corrosive, flammable, or explosive.
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Assignment:
page 245 "A Survey of
Household Hazardous Wastes"
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Lesson 8: Waste Management – The 4 R's
1. Reduce - use products that have less packaging.
Ex. bulk foods
2. Reuse - use over again or for new purposes.
Ex. pop bottles
3. Recycle - collect, break it down and rebuild into
other products
Ex. aluminum cans
4. Recover - reclaim either waste material or
energy.
Ex. Burn waste materials and use the energy
recovered and convert
it to electrical energy.
Cons
Recycling does incur costs for transporting,
handling, sorting, cleaning, and storing.
Pros
Recycling paper requires 58% less water and
produces 74% less air pollution
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***Conserves energy and resources***
Assignment 8: p. 252 #1-5 (copy question)
p. 253 – key terms
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Lesson 9: Landfill Construction and Design Solid Waste Disposal
Incineration -
reduces volume to approximately 5% and the ash is disposed of in landfill.
However, gases produced contribute to air pollution.
Sanitary Landfill Sites
- To avoid possibility of any toxic wastes entering the water
supply by seeping into the ground water they use clay and/or plastic liner on the bottom.
 Landfill must be monitored to make sure these is no leaching
Household things that leach:
 Cadmium from old fridges
 Lead from paints
 Mercury from electrical equipment
- Anaerobic conditions created by burying organic waste results in the production of
carbon dioxide and methane. – methane gas will filter up to the surface, which creates the
possibility of explosion. Many landfills pipe the methane to the surface and burn or ‘flare
off' the gas in a controlled manner
Secure Landfills - are used to dispose of hazardous and toxic wastes.
Contents are enclosed by thick plastic liner and two or more layers of clay. A gravel bed
between the clay layers collects any leachate.

Leachate - the liquid that results when wastes decompose and rainwater filters down
through the landfill, is collected and sent to waste water-treatment centres.

Bioremediation - method of using living organisms to reduce hazardous substances
to less noxious forms.

Bioreactors - tanks containing bacteria species that can attack and break down
some of the more persistent and toxic wastes.
Assignment 9: p. 253 #1- 6, 10, 11
p. 259 #1-8 (copy question)
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Lesson 10: Review
Unit 3 Review
Pages 258 - 259 # 1-8, 10-12, 14-22 (in class and homework)
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Lesson 14:
Review Pages26O- 261 #23,25,27-38
Quiz Topics 4-6
Unit 3 Test
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