This lecture was presented at Melbourne Grammar School, for the Victorian Association of Environmental Education for students of VCE Environmental Science, prior to their Unit 4 exam.
Unit 4 Exam Revision Lecture - VCE Environmental Science - Area of Study 1 - Pollution
1. Unit 4 VCE
Environmental Science
Area of Study 1: Pollution
Revision Lecture
Saturday 17th November
S
2. The Exam – 90 minutes
S Starts 9.00am Monday 19th November
S 15 minutes reading time
S Section A: 20 multiple choice questions (each worth 1
mark)
S Allow 20 minutes (1 minute per mark)
S Section B: 5 short answer questions (worth 70 marks)
S Allow 70 minutes (1 minute per mark)
S Finishes (Yay!)
3. Break down of marks
S Mercury/sulfur dioxide: 15 marks
S Definitions: 5 - 10 marks
52 marks/90 = about 58%
S Graphs/data: 5 marks
S Case study pollutant: 16 - 22 marks
S Environmental Project: 17 marks
S Evaluation of a project: 12 marks
S Ecotourism: 9 marks
4. Which are not pollutants?
S Milk S Noise
S Hot water S Light
S Carbon dioxide S Food scraps
S Ozone S Leaves
S Soil S Chocolate
5. What is a pollutant?
S “The presence in or introduction into the
environment of a substance or thing that has harmful
or poisonous effects.”
S “The contamination of air, water, or soil by
substances that are harmful to living organisms.
Pollution can occur naturally, for example through
volcanic eruptions, or as the result of human
activities, such as the spilling of oil or disposal of
industrial waste.”
6. Practice Question 1:
Which of the following statements about pollutants is
true :
A. Pollutants are only harmful to humans
B. Pollutants alter the environment in a negative
way
C. Pollutants refer specifically to toxic inorganic
substances made by humans
D. Pollutants are harmful organic substances that
negatively effect plants and animals
7. Practice Question 2:
The following are all pollutants in the
atmosphere, with one exception. Choose the
exception:
A. Carbon monoxide
B. Nitrogen dioxide
C. Nitrogen gas
D. Ozone
8. AoS 1: Pollution and Health
S General characteristics of mercury and sulfur dioxide as
pollutants
S Point and diffuse sources of pollution and pollutant
sinks
S Transport mechanisms, including
persistence, mobility, bioaccumulation
S Environmental human health, health of the
environment, environmental hazards
S Exposure, dosage, chronic and acute
toxicity, allergies, specificity and synergistic action.
9. Properties: Fate:
• Solid /liquid /gas •Persistence
• Volatility •Elimination
• Flammability Mobility:
• Solubility • Transport
mechanisms
Impact:
•Exposure •Effects on
Source Organisms
•Dosage and
•Toxicity Environment
Strategies to
mitigate effects
10. Sources – match the terms
S Point S Man-made
S Diffuse S On the move
S Fugitive S “Sneaking out” – difficult to locate
S Mobile S Needs to be shaded on a map -
area
S Natural
S Can be pin-pointed on a map
S Anthropogenic
S Environmental sources – eg. rocks
11. Sources – match the terms
S Point S Can be pin-pointed on a map
S Diffuse S Needs to be shaded on a map -
area
S Fugitive
S “Sneaking out” – difficult to locate
S Mobile
S On the move
S Natural
S Environmental sources – eg. Rocks
S Anthropogenic
S Man-made
13. Point Sources
Pollutants released from specific points
that may be collected, treated or
controlled
S domestic waste water
S industrial wastes
S sewage treatment effluent
S chimneys releasing gaseous
and particulate emissions
14. Practise question 3:
S Mercury particles are emitted from a smokestack at an
industrial plant. The smokestack is an example of a
A. Point source
B. Diffuse source
C. Fugitive source
D. Transport mechanism
15. Diffuse Sources
Pollutants released from many
points that are difficult to
collect, treat or control
S Oil spills
S Rubbish tip leak
S Fertiliser in run-off
S Pesticide spraying
Sometimes a matter of
scale!
16. Practice Question 4:
Which one of the following is an example of
a diffuse source of pollution?
A. highway carrying heavy traffic
B. chimney stack
C. sewerage pipe
D. pipe discharging waste from a
manufacturing plant
17. Point and non-point sources
S Car exhaust pipes will
be considered a point
source on a small scale
S At a larger scale, many
vehicles on a freeway
will be mobile sources
of diffuse emissions
18. Transport Mechanisms
S By air/wind (usually gaseous, liquid droplets or small
particulates)
S By water (dissolves in precipitation, usually
soluble, also heavy metals, sometimes volatile
hydrocarbons – vaporises easily)
S By soil (erosion by wind or water can move soil-
borne pollutants, as can heavy machinery and other
anthropogenic activities)
S By organisms – bacteria, plants and animals
19. Sinks
S Where does the pollutant end up? Where does it spend
significant amounts of time?
S Diluted in the air
S Diluted in water – swamps, wetlands, lakes and oceans
S Sediments in streams, rivers, estuaries, swamps etc
S In the soil
20. Types of pollution
Air pollutants
Smog
Water pollutants
Heavy metals
Endocrine disrupting chemicals
S
21. Air pollutants
S Carbon monoxide and S Particulate matter
CO2
S Pollen, dust-mites and
S Nitrogen oxides (esp. other allergens
NO2)
S Radioactive compounds
S CFC’s
S Oxides of Sulphur (esp.
S Volatile Organic SO2)
Compounds
S Ammonia
S Odours
22. Smog – VOC‟s, NOx, O3 &
particulates
S A combination of
pollutants and weather
conditions can result in
photo-chemical smog
S Can cause asthma &
allergies
S Synergistic effects
23. What is synergy?
S When the effect of both pollutants together is greater than
the sum of the effects of each pollutant by itself.
S When 1 + 1 = 3 !
S Includes each pollutant acting on their own AND any
reactions between the pollutants
S Photochemical smog is the classic example of this.
24. Water pollutants
S Soluble chemicals such as fluoride, phosphates, various
salts
S Sediments, contributing to turbidity (restricts light)
S Oil and other volatile hydrocarbons
S Heavy metals (mercury, arsenic, cadmium etc)
S Physical contaminants (litter, leaves)
S Biological contaminants ( E.coli )
S Can hot water be considered a pollutant?
25. Heavy metals
S Mercury, chromium, arsenic, cadmium, lead and
manganese.
S Characterised by high atomic weight
S Persistent, tend to bioaccumulate and biomagnify
S Allergic reactions (e.g., beryllium, chromium)
S Neurotoxicity – affects nervous system (e.g. mercury &
lead)
S Nephrotoxicity – affects kidneys (e.g. mercuric chloride)
S Cancer
26. Types of Mercury
Elemental mercury Inorganic mercury Organic mercury
Silver in color, stable, Water soluble salts (eg. Methyl mercury is fat
liquid at room Mercuric chloride) soluble (and therefor
temperature, fat-soluble insoluble in water),but
and bioaccumulates. Inorganic mercury is found in waterways and
converted to methyl bioaccumulates.
Vapourises easily and mercury by bacteria.
can be absorbed
dermally.
“Students needed to understand the different forms of mercury
and the characteristics of each” Examiners report, 2009
27. Practise question 5:
S Methyl mercury can be absorbed over a long period of
time if a person experiences
A. Acute toxicity
B. It‟s direct effects
C. Acute absorption
D. Chronic exposure
28. Practise question 6:
Elemental Mercury can vapourise at room temperature.
This increases the likelihood of
A. Bioremediation by plant roots
B. Exposure of humans to elemental mercury
C. Waterborne transport of elemental mercury
D. High persistence of elemental mercury at a particular
site.
29. Practise question 7:
S Which one of the following forms of mercury is most likely
to be involved in bioaccumulation, with the correct
reason?
A. Methyl mercury, as it is soluble in fat
B. Elemental mercury, as it is persistent
C. Methyl mercury, as it is soluble in water
D. Oxides of mercury, as they are soluble in water
30. Case study of a pollutant
Characteristics of a specific pollutant including:
S Physical and chemical characteristics
S Sources, transport mechanisms and sinks
S Does it bioaccumulate or biomagnify?
S Environmental health effects (hazardous
quantities)
S Human health effects (direct and indirect –
dosage)
S Strategies that reduce the risk of pollutants
affecting human health and the environment
31. What is your case study?
S Phosphorus
S Oxides of nitrogen
S Fluoride
S Lead
S Arsenic
32. Physical & chemical
characteristics
Mercury Sulphur dioxide
S Very heavy metal, liquid at S Colourless gas, denser than
room temp. air at room temp.
S Silver-white, odourless S Strong, suffocating odour
S Non-flammable
S Dissolves in fats &
oils, insoluble in water S SO2 + O2 SO3
S Methyl mercury is also S SO3 + H2O H2SO3
insoluble in water
S Acts synergistically with
S Forms alloys with other smog
metals
33. Natural sources
Mercury Sulphur dioxide
S Rocks and ores S Geothermal activity
S Evaporates from S Natural decay of
soils vegetation on
land, in wetlands
S Volcanic activity
and oceans
34. Anthropogenic sources
Mercury Sulphur dioxide
S Burning of fossil fuels S Burning of fossil fuels
S Precious metal mining S Wood pulping & paper
manufacture
S Compact fluorescent
globes S Metal refining and
smelting
S Felt & hat making
35. Transport mechanisms
Mercury Sulphur dioxide
S From fossil fuel stations and S From vehicles and industrial
mining sites, mercury may sites, pollutants like sulphur
be carried by wind and dioxide may be carried by
wind primarily in the
rainfall moving over and direction of the prevailing
through the ground. wind.
S Sediments are deposited in S As it moves it may react with
lakes, rivers, wetlands, coas oxygen and then water
tal waters resulting in sulphuric acid
which falls to the ground
S Plants and animals absorb with acid rain burning plants
and ingest the pollutant and (our food) and acidifying our
it ends up in the food chain water
36. Persistence & Sinks
Mercury Sulphur dioxide
S Highly persistent S Low/medium
persistence
S Exposure via ingestion
S Exposure via inhalation
S Bioaccumulates
S Wetlands, lakes,
S Sinks are sediments oceans
and organisms S Absorbed by soils and
plants
37. Human health effects
Mercury Sulphur dioxide
S Eating fish or shellfish which have S Combines with oxygen and
been exposed to mercury - Drinking water vapour to form sulfuric
water or eating foods that contain acid and has synergistic effects
traces of mercury - Being exposed in smog with oxides of nitrogen.
to mercury from dental work and Strong, acrid odour and can
medical treatments - Breathing cause respiratory
contaminated air - Working at, or problems, especially in people
living near, factories where mercury with impaired lung function
is produced or used, such as fossil (asthmatics, babies and the
fuel plants or cement elderly).
manufacturers.
http://www.abc.net.au/news/2012-
08-25/the-bitter-dispute-over-the-
toxic-legacy-of/4222392
38. Human Health Effects
Mercury Sulphur dioxide
S Fat soluble, so can impair brain S 10-50 ppm causes eye, nose
function and cause neurological and throat irritation, choking
damage. and coughing.
S At higher levels, causes
S Irritability, tremors and „mad-
inflammation of the respiratory
hatter‟ syndrome tract, wheezing and lung
damage.
S Water soluble compounds
cause kidney damage. S Most severe impacts on infants,
the elderly and people with
respiratory problems such as
allergies and asthma.
39. Environmental health effects
Mercury Sulphur dioxide
S Bioaccumulates in S Combines with oxygen and
organisms, especially methyl- water vapour to form sulfuric
mercury, as it is found in water acid, which results in acid rain.
and absorbed by aquatic This can cause decreased pH
organisms. As it builds up in the (acidification) of waterways,
food chain, (biomagnifies) plant death and therefor impact
organisms higher up are more aquatic food chains.
affected.
40. Practise question 8:
S Mercury can be particularly hazardous to human and
animal health because of bioaccumulation.
Bioaccumulation
A. Is caused by excessive exposure to mercury in the air
B. Occurs because the person or animal is allergic to
mercury
C. Is due to synergism between mercury and another
pollutant in the ecosystem
D. Occurs because the rate of intake exceeds the rate at
which the body can remove it.
41. Practise question 9:
S Bioaccumulation of mercury is most likely to occur in
A. Aquatic organisms
B. Animals high up in the food chain
C. Sediment in lakes containing mercury
D. Animals that are low in fat, and so are unable to store
the mercury, which is fat soluble.
42. Management strategies
Mercury Sulphur dioxide
S Minimise use in extracting S Use low-sulphur coal
& smelting
S Change extraction process
S Replace with alternatives
S Reduce fugitive emissions
S Reduce fugitive
emissions S Control devices
(scrubbers, tall
S Pollution control devices?
stacks, acid-plants)
43. Endocrine disrupting
chemicals
S “emerging issues in human health”
S Endocrine disruptors are chemicals that
interfere with endocrine (or hormone
system) in animals, including humans.
S Can cause cancerous tumours, birth
defects, and other developmental
disorders.
S Pesticides (such as DDT), PCB‟s,
Bisphenol A (BPA), Polybrominated
diphenyl ethers (PBDE)Pthalates and
44. Section B: Short answer
S A power station fuelled by coal can produce sulfur
dioxide, leading to the formation of acid rain.
S Describe why a power station can generate SO2 (2
marks)
S List 4 characteristics of Sulfur dioxide (2 marks)
S Describe the effect on human health of exposure to high
concentrations of SO2 (2 marks)
S 2 + 2 + 2 + 2 + 2 = 10 marks 10/90 = 11% of exam
45. Section B: Short answer
S Describe the processes involved in the formation of acid
rain due to the emissions of SO2 from the chimney of a
power station, including the likely transport mechanisms.
(2 marks)
S Describe two methods by which the power station owners
could reduce the sulfur dioxide produced by their station.
(2 marks)
46. Samples are taken at
each of locations A, B, C
and D.
Each sample is tested for
three pollutants I, II, and
III.
47. Pollutant I Pollutant II Pollutant III
Site A Low Low Low
(water)
Site B Low High Medium
(water)
Site C Medium Medium Medium
(air)
Site D High High High
(air)
What evidence is there that the pollutants are coming from the factory?
Which pollutant is most likely to be sulphur dioxide and mercury? Explain.
What pollutant could III be. Explain.
48. Human Health Effects
Methods of exposure
Pathways of pollutants
Dosage
Toxicity and LD50
S
49. Exposure : Dosage : the Toxicity : a
How much of a amount of a measure of the
pollutant an chemical influenced
by harm a
organism is exposed absorbed per substance can
to over a specific unit body cause an
period of time. weight. organism.
influences
Ingestion influenced
by
Inhalation Respiration rate
Hazard concentration
Dermal Frequency of exposure
absorption Length of exposure
Properties of the chemical Impact
Body size
Allergies
50. Methods of Exposure
S “Routes of entry”
S Ingestion - Via mouth to digestive system (usually
liquids and solids in food)
S Inhalation - Via nose & mouth to respiratory
system (usually gases, droplets or small
particulates)
S Absorption – Via skin (dermally – usually liquids
or gases)
51.
52. Measuring pollutants
S Grams (or mg) per unit volume (air or water)
S For example, g/litre or mg/litre or g/m3
S Gases measured in ppm or ppb
S Emissions can also be measured per unit time (eg.
g/min)
S Check for SALT on your graphs
(Scale, Axes, Labels, Title)
53.
54. Practise question 10:
S The mass of mercury contained in a 350g sample of soil
collected from a distance of 600m from the plant chimney
would be closest to:
A. 80 mg
B. 280 mg
C. 350 mg
D. 600 mg
55.
56. Practise question 11:
S What percentage of measurements were within the
government‟s target concentration (less than 0.012ppm)
for the pollutant gas?
A. 14%
B. 33%
C. 67%
D. 100%
57. Practise question 12:
S Angie spent different periods at each location making her
measurements. Which of the following represents her
greatest exposure to the pollutant gas?
A. 2 minutes at 6 km south
B. 3 minutes at 1 km south
C. 4 minutes at 1 km north
D. 5 minutes at 8 km north
58. Pathways of pollutants
S Risk to organisms and the environment depends upon
how the pollutant is transported through the
environment.
S Particles or compounds that can be dispersed by air /
wind currents are likely to be inhaled, absorbed
through dermal contact and ingested.
S Compounds that dissolve in and are dispersed by
water are likely to be ingested, absorbed through
dermal contact but are less likely to be inhaled by
terrestrial organisms.
S Compounds that are fat soluble are likely to
biomagnify and therefore pass through the food web
59. Dosage
The dosage someone receives will depend on the:
S Rate of respiration/ingestion/absorption
S Length of exposure
S Frequency of exposure
S Concentration of pollutant
S Physical, chemical and biological properties of the
pollutant
http://www.biology.arizona.edu/chh/problem_sets/toxicology/t
oxicology.html
66. Section B: Case study
S Name a pollutant you have studied this year
S Describe a precise geographical location where you would find
this pollutant (2 marks)
S Explain how the concentration of this pollutant is measured -
equipment and units (2 marks)
S Consider the life cycle of this pollutant, naming it‟s source
(point or diffuse?), transport mechanism and major sink
S (2 + 2 + 3 + 2 = 9 marks)
67. Section B: Case study
S Identify a specific human or animal population affected by
this pollutant , including method of exposure. (2 marks)
S State the dosage of the pollutant required to cause
significant harm to an individual of the population. (2
marks)
S Describe a strategy that has been used to reduce the
pollutant or the impact on human or animal health. (2
marks)
68. Section B: Case study
S Evaluate the effectiveness of this strategy using
evidence. (3 marks)
TOTAL for your case study
2 + 2 + 3 + 2 + 2 + 2 + 2 + 3 = 18 marks/90
20% of the exam
69.
70. Monitoring is not a strategy!
S Monitoring or measuring the pollutant is NOT a strategy
that reduces emissions or exposure
S Research, by itself, cannot reduce emissions or
exposure
S Education, by itself cannot reduce emissions or
exposure
S These actions may be part of a plan to reduce human
and environmental health but when asked for a strategy
to reduce impact you need to discuss the ACTIONS
that control emissions at their source and/or reduce
71. Exam Preparation
Preparing yourself
Materials you should take
Using your reading time
Writing time begins
Marks are a guide to answers
S
72. Preparing yourself
S get enough rest and sleep
S eat sensibly, don't skip meals or try to fill up on snacks -
active brains need a balanced diet
S check on the starting time and allow plenty of time to get
to your examination centre
S check that you have everything you need - make yourself
a list
73. Materials you should take
S one or two highlighters - you can use these to highlight 'action
words' that guide you in how to answer each question, key
information and data in each question or questions that you
know you may want to come back to during your 5 minutes
checking time
S clear (transparent) ruler
S two pencils (with extra lead or a sharpener)
S eraser
S scientific calculator (either with new batteries or a back up
scientific calculator)
74. Using your reading time
S One strategy that works for many students during the 15
minutes of reading time is to:
S Spend the first minute or two simply 'flicking through' the
examination paper to gain a snapshot of the length of the
paper, layout of questions, occurrence of figures such as
graphs, tables and drawings.
S Check all pages and questions are present as described on
the front cover of the examination booklet
75. Using your reading time
S Follow this up with scanning each question very
briefly to determine its focus; for example, is the
question related to Pollution or Applied
Environmental Science and ask yourself whether
the question requires a definition, analysis of
data, evaluation with evidence or is another type of
question. (This may only require 6-8 seconds per
question, and sometimes less.) It is not necessary at
this stage to begin solving for the answers but simply
allow your brain to begin processing the
information.
76. Writing time begins…
S Once writing time begins, try to stay calm. You will have
90 minutes to complete the exam. You might like to start
with a question that you feel is straightforward. Use your
highlighter to identify the 'action words' (such
as name/nominate, describe, explain, outline,
evaluate, justify)
S Don‟t list or describe more examples than asked for in a
particular question - if you think of a better quality
response than you first wrote, clearly identify (by
highlighting, underlining or circling) the examples you
wish the examiner to assess.
77. Marks are a guide to
answers
S Check how many marks each question is worth – 3 marks
means three key points.
S If you find yourself writing much more than the lines and
space provide for in a particular question, then it is possible
that you are writing too much and you should consider
using dot points. It is important that you allow yourself
sufficient time. Attempt all questions, even if you are not
entirely confident of your answers - examiners cannot
award marks to empty spaces.