Transcript Environmental Problems, Their Causes, and Sustainability

Chapter 2 – Science, Matter, Energy
and Systems
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Endeavor to discover how nature works
and to use that knowledge to make
predictions about what is likely to happen
in nature.
Science
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Science is a discipline that attempts to
describe the natural world in terms of
order.
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Biology
Chemistry
Physics
Earth Science
Inference
1.
2.
3.
To conclude from evidence or premises
To reason from circumstance; surmise: We
can infer that his motive in publishing the
diary was less than honorable
To lead to as a consequence or conclusion:
“Socrates argued that a statue inferred the
existence of a sculptor”
Scientific method
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HYPOTHESIS – proposed to
explain observed patterns
Critical experiments
Analysis and conclusions
Scientific Methods
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What is the question to be answered?
What relevant facts and data are known?
What new data should be collected?
After collection, can it be used to make a
law?
What hypothesis can be invented to explain
this? How can it become a theory?
Theory and Law
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Scientific Theory
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A hypothesis that has been supported by
multiple scientists’ experiments in multiple
locations
A Scientific Law
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a description of what we find happening in
nature over and over again in a certain way
Scientific Laws
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Law of Conservation of Matter
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Matter can be changed from one form to
another, but never created or destroyed.
Atomic Theory of Matter
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All matter is made of atoms which cannot be
destroyed, created, or subdivided.
Reasoning
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Inductive Reasoning
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Uses observations and facts to arrive at
hypotheses
All mammals breathe oxygen.
Deductive Reasoning
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Uses logic to arrive at a specific
conclusion based on a generalization
All birds have feathers, Eagles are birds,
therefore All eagles have feathers.
Frontier and Consensus Science
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Frontier Science
 Scientific
“breakthroughs” and controversial
data that has not been widely tested or accepted
 String Theory
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Consensus or Applied Science
 Consists
of data, theories, and laws that are
widely accepted by scientists considered experts
in the field involved
 Human Genome Project
Models
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Scientists use models to imitate the system.
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Mice are used to determine LD50
Chemists use structural models when
investigating a chemical
Remember the plum pudding!
Mathematical and computer models are able
to predict many outcomes
Models have Factors
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Factors represent the variables in a
scientific theory
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The factors that are involved in a theory
about why you are late to my class
your walking speed
 interference by your peers
 the distance from point A to my room
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A Good Scientist . . .
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Always makes observations.
Always questions.
Always using good scientific practices to
record and analyze data.
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Repeats trials
Uses statistics to analyze data
Uses safe and accepted practices
Uses data to support hypotheses
Experiments
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Variables are what affect processes in the
experiment.
Controlled experiments have only one variable
Experimental group gets the variable
Control group does not have the variable
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Placebo is a harmless pill that resembles the pill being
tested.
In double blind experiments, neither the patient nor the
doctors know who is the control or experiment group.
Let’s Enter the New Age of
Science
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Six Sigma (6δ) is an industry wide method
of materials and production management
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Six sigma utilizes International Standards
Organization (ISO) guidelines to effectively
manage industrial processes.
The goal of 6δ is total customer satisfaction
through lowering cost, faster and more
efficient production, and zero-defect
products.
6δ Problem Solving Strategies
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We are going to apply these principles to
the scientific process
Knowledge Based Management: taking the
questions to ask, the questions to answer
and the tools and techniques to answer
them.
Process Flow Diagram
Observation
Input
Hypothesis
Decision
Yes
No
Experiment
Process
Data
Output
Conclusion
Variables
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A variable is a source or variance in an
experiment and include independent and
dependent variables.
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Independent variable (x-axis): the variable
which is changed in an experiment.
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Dependent variable (y-axis): the variable
which is measured in an experiment.
Identifying Variables
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The 6 method of problem solving uses a
“fishbone” diagram or a cause-and-effect
diagram.
The variables are:
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Man
Machine
Measurement
- Environment
- Method
- Materials
Cause and Effect Diagram
Man
Machine Measurement
Effect
Method
Materials Environment
Measurements
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In science, data is collected through
observations and measurement.
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A measurement has
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magnitude,
units,and
some degree of uncertainty.
Units
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A number by itself means nothing! (unless
it is meant to stand along like specific
gravity)
Scientists use ppm (part per million) to
measure pollutant concentration
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concentration = mass solute per volume of
solution!!!
ppm means 1 mg per 1000mL (1 mg/L)
ppb means 1 ug/L
Accuracy Vs
Precision
Accuracy – measurement agrees with the
accepted correct value
Precision – measure of reproducibility
Adjustments
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If your data is precise, but not accurate,
simply adjust your measurement
techniques.
If your data is neither precise nor accurate,
you will need to adjust the equipment and
the procedure.
Time Delay
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Science does not always occur
instantaneously. There is often a time
delay from the introduction of a variable
until observable effects.
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Short time delay: ice on a stove = melts
quickly
Long time delay: ice in a refrigerator = melts
slowly
Name some in the environment!
Significance of Numbers
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Each number of a measurement is
significant (has meaning), including the
last digit.
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The last digit is estimated.
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Significant
Figure
Rules
All non-zero numbers (1-9) are significant.
Zeros are significant if they come between
two significant figures.
Zeros are significant to the right of the
decimal IF they follow a significant figure.
(0.0000100000)
Trailing zeros to the left of the decimal are
only significant if there is a decimal.
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Calculating With Sig Figs
When there are multiple functions,
complete all functions and determine
significant figures at the end.
The least number of decimal places or
significant figures determines the number
in the final answer.
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Adding/Subtracting: only count decimal
places.
Multiplication/Division: count significant
figures.
Example
50.222 + 34.22 x 10.00000 =
3 decimal places + (4 sig figs x 7 sig figs)
50.222 + 342.00000=
392.422
answer should have 4 sig figs with no more than 2 decimal places
That’s your final
answer
392.4
Long Division and
Multiplication
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Practice dividing and multiplying the
following by hand
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1520 ÷ 23
70 ÷ 1.35
1.2 x 1023 ÷ 2.4 x 10-3
50222 x 233
100000000 x 340000
75002 x 0.00123
Scientific Notation
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Used to express very large or very small
numbers
Multiplying and dividing factors
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multiply, add exponents
divide subtract exponents
Percentages
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A percentage is a ratio of 100
5% is 0.05 x 100
What is 3.5% of 1,999,220?
What percentage of animals is 255 out of
3420?
Dimensional Analysis
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You MUST solve all problems using this
format
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known x conversion factor = answer
If you have 2.35 kg of a sample whose
density is 1.25 g/mL, how many Liters of
sample do you have?
Chemistry Review
What does it matter?
Matter
Pure
Substances
Compound
(molecule)
Element
(atom)
Mixtures
Homogeneous
Heterogeneous
Laws of Matter
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Law of Conservation of Matter: matter is
neither created nor destroyed, it simply
changes form.
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Law of Definite Proportions: atoms come
together in small whole number ratios to
form unique chemical compounds.
States of Matter
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Solid: atoms do not move and are close
together in a fixed volume and shape.
Liquid: atoms move freely within the
shape of the container with a fixed volume.
Gas: atoms move freely far apart from
each other; no fixed volume or shape.
Atoms
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Nucleus made up of Protons (+) and
Neutrons (neutral)
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Atomic Mass Number
Electrons (-) arranged in orbitals around
the nucleus
Atomic Number: number of protons
Isotope: same number of protons, different
number of neutrons
Ions
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Ion: an atom with a charge
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Cation: positive ion
Anion: negative ion
pH: measure of -log10[H3O+]
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measure how acidic or basic (0-14 S.U.)
Physical and Chemical
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A physical property describes a chemical
using the five senses.
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Physical change involves the change in a
physical property.
A chemical property describes the relative
ability of a chemical to react.
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Chemical change results in a new compound.
Matter quality
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Measure of how useful a matter is
for humans based on availability
and concentration
Some Important elements- composition by
weight – only 8 elements make up 98.5% of
the Earth’s crust
Organic
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Organic compounds are Carbon based.
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The backbone of the compound is Carbon
with Oxygen, Hydrogen, Nitrogen, etc. at
specific locations
Organic Compounds
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with carbon
sugar, vitamins, plastics, aspirin
Inorganic compounds
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no carbon,not originating from a
living source
Earth’s crust – minerals,water
water, nitrous oxide, nitric oxide,
carbon monoxide, carbon dioxide,
sodium chloride, ammonia
Biological Matter
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Prokaryotes: unicellular, without nuclear
membrane
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Bacteria
Eukaryotes: multicelluar organisms with
cellular and nuclear membranes
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algae, fungi, animals, etc.
Macromolecules
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Macromolecules are very large molecules
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proteins
amino acids
DNA
Genes are collections of nucleotides in a
strand of DNA which express physical
characteristics; all genes together form a
Chromosome
Energy
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capacity to do work and transfer heat
Kinetic Energy -energy in action
electromagnetic radiation, heat,
temperature
Potential energy - stored energy that is
potentially available
Energy sources
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97% solar
without it earth’s temperature 240 C
1% - non commercial(wood, dung,
crops) + commercial ( burning
mineral resources)
Energy quality
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Measure of
how useful an
energy source
is in terms of
concentration
and ability to
perform useful
work
Electromagnetic Radiation
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Electromagnetic Radiation is a selfpropagating wave that moves through
space or matter.
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Electric and Magnetic components
It has properties of waves.
Electromagnetic radiation
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different wave lengths shorter – high
energy, disrupts cells with long term
exposure
Use….radioisotopes
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Estimate age of rocks and fossils
Tracers in pollution detection and
medicine
Genetic control of insects
1st Law of Energy or 1st Law of
Thermodynamics
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in all physical and chemical
changes energy is neither created
or destroyed
energy input always equal to
energy output
2nd Law of Energy or 2nd Law of
Thermodynamics
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when energy is changed from one
form to another some of the useful
energy is always degraded to
lower quality, more dispersed, less
useful energy(heat)
Nuclear Material
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An atom will release energy as
electromagnetic radiation in order to
become stable.
A stable nucleus has at least as many or
more neutrons as protons.
Atoms with a mass #209 or greater are
never stable.
Nuclear Changes
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nuclei of certain isotopes spontaneously change
(radioisotopes) or made to change into one or
more different isotopes
Alpha particles – fast moving (2
protons+2neutrons); Beta particles – high speed
electrons ; Gamma particles - high energy
electromagnetic radiation
radioactive decay, nuclear fission, nuclear
fusion
Nuclear Fission
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Nuclear fission is the process of splitting
atoms.
Fissile isotopes are isotopes of an element
that can be split through fission.
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Only certain isotopes of certain elements are
fissile. For example, one isotope of uranium,
235U, is fissile, while another isotope, 238U, is
not.
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certain isotopes
(uranium 235) split
apart into lighter
nuclei when struck
by neutrons
chain reaction
releases energy
needs critical mass
of fissionable
nuclei
Nuclear Fission
Nuclear fusion
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two isotopes (hydrogen) forced together at
extremely high temperatures (100 million
C)
uncontrolled nuclear fusion thermonuclear
weapons
Nuclear Fusion
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Nuclear fusion is the joining of two atomic
nuclei. It occurs in stars all over the universe,
including our Sun, and is what provides the
warmth and light we receive.
1H + 1H  2H + positron (ß+) + neutrino (v)
2H + 1H 3He + gamma ray (y)
3He + 3He  4He + 1H + 1H
Decay
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Radioactive decay is when unstable
isotopes emit particles.
There are three main types of radiation:
* Alpha radiation
* Beta radiation
* Gamma radiation
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Half Life
The rate of radioactive decay is related to the
energy change that accompanies the
transformation, but it is not a direct
relationship.
The rate of radioactive emissions of a
radioactive nuclide is directly proportional to
the amount of radioactive material present.
The rate of decay of a radioactive nuclide is
measured by its half-life.
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The half-life of a radioactive substance is
the time it takes for half of an initial
amount of the substance to decay.
The half-live is independent of chemical
activity, external pressure, and temperature.
Half-Life Formula
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T = half life
t = total time elapsed
Fraction remaining = 1/2 (t/T)
Number of half-life periods = t / T
Uranium
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Uranium is the principle element used in nuclear
reactors and in certain types of atomic bombs.
The specific isotope used is 235U.
235U + 1 neutron  2 neutrons + 92Kr + 142Ba +
ENERGY
235U + 1 neutron  2 neutrons + 92Sr + 140Xe +
ENERGY
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Chain Reaction
When the atom is split, 1 additional
neutron is released. If more 235U is
present, those 2 neutrons can cause 2 more
atoms to split. Each of those atoms releases
1 more neutron bringing the total neutrons
to 4.
The chain reaction will continue until all
the 235U fuel is spent. This is roughly what
happens in an atomic bomb. It is called a
runaway nuclear reaction.
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Positron is a positive electron
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e+
Gamma rays are electromagnetic radiation
with a lot of power
Feedback Loops
A feedback
loop
occurs when an output
of a system is fed back
as an input
Two kinds of feedback
loops
Positive
 Negative
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Positive Feedback
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A feedback loop in which output of one
type acts as input that moves the system in
the same direction. The input and output
drive the system further toward one
extreme or another.
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Positive feedback will result in exponential
(unlimited) growth.
Positive feedback is BAD
Positive feedback loop
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Exponential growth of population –
more individuals lead to increased
number of births
Negative Feedback
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A feedback loop in which the output of one
type acts as input that moves the system in
the opposite direction. The input and
output essentially neutralize each other’s
effects and stabilizes the system.
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A thermostat in a room controls and
maintains the temperature.
Negative feedback is GOOD
Negative feedback loop
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Temperature regulation in humans –
increased temperature leads to decrease in
temperature by sweating
High Throughput
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A high throughput economy is one that has
a high output.
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The economy is boosted by a one-way flow
of matter/energy
Generates a large amount of waste and
pollution
Energy output is low quality
Low Throughput
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A Low Throughput economy is one that
has a balance of input and output.
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Generates little waste
Maximizes energy efficiency
Not an economic leader but a environmental
leader
Recycling and Reuse
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A Recycling and Reuse economy mimics
nature by recycling and re-using matter and
energy.
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an environmentally sustainable economy
Pollutants
Tying the themes together.
Pollutants
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Remember the definition of pollution?
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The presence of chemicals at high enough
levels to threaten the health of humans and
other organisms.
The EPA uses a vague definition of
pollutant to define environmental “hazard”
There are 5 types of pollution that we will
focus on.
Persistent
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Persistent pollutants are those that can be
detected in the environment for a very long
time.
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Bioaccumulative chemicals that cannot be
removed from the body of fish or other
animals are stored in fatty tissue; other
organisms store the chemicals in their cell
wall or other cellular structures.
Rachel Carson highlighted DDT.
Degradable
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A degradable pollutant is one that is
broken down completely in the
environment or reduced to an acceptable
level.
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Just because a pollutant breaks down, the
products may be just as harmful!!!
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DDT degrades into DDE and DDD
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Dicholorodiphenyltrichloroethylene (DDT)
Dichlorodiphenyldichloroethylene (DDE)
Dichlorodiphenyldiphenyldichloroethane (DDD)
Biodegradable
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A biodegradable pollutant is one that can
be broken down or neutralized by a living
organism.
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The basis of a septic system is for bacteria to
ingest waste including paper products.
Biodegradable waste can take as few as
several hours or as many as several years to
degrade.
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Still fills up a landfill or a septic system though!
Slowly Degradable
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A pollutant that is slowly degradable takes
as long as several decades to breakdown.
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Some biodegradable plastics such as grocery
bags or food wrap, diapers, etc.
Cotton and other organic materials sold as
consumable products.
Non-biodegradable
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Non-biodegradable refers to those
pollutants that cannot be broken down by
natural processes.
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There are some chemical degradation
processes available.
These wastes are filling up landfills and waste
processing plants.
Environmental Science has
limitations……………….
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Cannot prove anything absolutely
Cannot be totally free of bias
Use of statistical tools
Huge number of interacting variables
Complex systems
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Time lags – change in a system leads to other
changes after a delay – lung cancer
Resistance to change – built in resistance –
political, economic
Synergy-when two or more processes interact
so that the combined effect is greater
Chaos – unpredictable behavior in a
system
Synergy and Chaos
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Synergy occurs when two or more processes
interact so the combined effect is greater
than the sum of the separate effects
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Grapefruit and Statins
Chaos occurs in a system when there is no
pattern and it never repeats itself
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Noise versus Music
Implications for the environment –
High waste society
Implications for the environment –
Low waste society
Gaia Hypothesis (1970)
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James Lovelock and Lynn
Marguilis