Published on November 18, 2012
Unit 4 VCEEnvironmental Science Area of Study 1: Pollution Revision Lecture Saturday 17th November S
The Exam – 90 minutesS Starts 9.00am Monday 19th NovemberS 15 minutes reading timeS 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!)
Break down of marksS Mercury/sulfur dioxide: 15 marksS Definitions: 5 - 10 marks 52 marks/90 = about 58%S Graphs/data: 5 marksS Case study pollutant: 16 - 22 marksS Environmental Project: 17 marksS Evaluation of a project: 12 marksS Ecotourism: 9 marks
Which are not pollutants?S Milk S NoiseS Hot water S LightS Carbon dioxide S Food scrapsS Ozone S LeavesS Soil S Chocolate
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.”
Practice Question 1:Which of the following statements about pollutants istrue : 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
Practice Question 2:The following are all pollutants in theatmosphere, with one exception. Choose theexception: A. Carbon monoxide B. Nitrogen dioxide C. Nitrogen gas D. Ozone
AoS 1: Pollution and HealthS 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.
Properties: Fate: • Solid /liquid /gas •Persistence • Volatility •Elimination • Flammability Mobility: • Solubility • Transport mechanisms Impact: •Exposure •Effects onSource Organisms •Dosage and •Toxicity Environment Strategies to mitigate effects
Sources – match the termsS Point S Man-madeS Diffuse S On the moveS Fugitive S “Sneaking out” – difficult to locateS Mobile S Needs to be shaded on a map - areaS Natural S Can be pin-pointed on a mapS Anthropogenic S Environmental sources – eg. rocks
Sources – match the termsS Point S Can be pin-pointed on a mapS Diffuse S Needs to be shaded on a map - areaS Fugitive S “Sneaking out” – difficult to locateS Mobile S On the moveS Natural S Environmental sources – eg. RocksS Anthropogenic S Man-made
Point SourcesPollutants released from specific pointsthat may be collected, treated orcontrolled S domestic waste water S industrial wastes S sewage treatment effluent S chimneys releasing gaseous and particulate emissions
Practise question 3:S Mercury particles are emitted from a smokestack at an industrial plant. The smokestack is an example of aA. Point sourceB. Diffuse sourceC. Fugitive sourceD. Transport mechanism
Diffuse SourcesPollutants released from manypoints that are difficult tocollect, treat or control S Oil spills S Rubbish tip leak S Fertiliser in run-off S Pesticide spraying Sometimes a matter of scale!
Practice Question 4:Which one of the following is an example ofa diffuse source of pollution?A. highway carrying heavy trafficB. chimney stackC. sewerage pipeD. pipe discharging waste from amanufacturing plant
Point and non-point sourcesS Car exhaust pipes will be considered a point source on a small scaleS At a larger scale, many vehicles on a freeway will be mobile sources of diffuse emissions
Transport MechanismsS 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
SinksS Where does the pollutant end up? Where does it spend significant amounts of time?S Diluted in the airS Diluted in water – swamps, wetlands, lakes and oceansS Sediments in streams, rivers, estuaries, swamps etcS In the soil
Types of pollution Air pollutants Smog Water pollutants Heavy metals Endocrine disrupting chemicals S
Air pollutantsS Carbon monoxide and S Particulate matter CO2 S Pollen, dust-mites andS Nitrogen oxides (esp. other allergens NO2) S Radioactive compoundsS CFC’s S Oxides of Sulphur (esp.S Volatile Organic SO2) CompoundsS AmmoniaS Odours
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
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 pollutantsS Photochemical smog is the classic example of this.
Water pollutantsS Soluble chemicals such as fluoride, phosphates, various saltsS Sediments, contributing to turbidity (restricts light)S Oil and other volatile hydrocarbonsS Heavy metals (mercury, arsenic, cadmium etc)S Physical contaminants (litter, leaves)S Biological contaminants ( E.coli )S Can hot water be considered a pollutant?
Heavy metalsS Mercury, chromium, arsenic, cadmium, lead and manganese.S Characterised by high atomic weightS Persistent, tend to bioaccumulate and biomagnifyS 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
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
Practise question 5:S Methyl mercury can be absorbed over a long period of time if a person experiencesA. Acute toxicityB. It‟s direct effectsC. Acute absorptionD. Chronic exposure
Practise question 6:Elemental Mercury can vapourise at room temperature.This increases the likelihood ofA. Bioremediation by plant rootsB. Exposure of humans to elemental mercuryC. Waterborne transport of elemental mercuryD. High persistence of elemental mercury at a particular site.
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 fatB. Elemental mercury, as it is persistentC. Methyl mercury, as it is soluble in waterD. Oxides of mercury, as they are soluble in water
Case study of a pollutantCharacteristics 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
What is your case study?S PhosphorusS Oxides of nitrogenS FluorideS LeadS Arsenic
Physical & chemical characteristics Mercury Sulphur dioxideS 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-flammableS Dissolves in fats & oils, insoluble in water S SO2 + O2 SO3S Methyl mercury is also S SO3 + H2O H2SO3 insoluble in water S Acts synergistically withS Forms alloys with other smog metals
Natural sources Mercury Sulphur dioxideS Rocks and ores S Geothermal activityS Evaporates from S Natural decay of soils vegetation on land, in wetlandsS Volcanic activity and oceans
Anthropogenic sources Mercury Sulphur dioxideS Burning of fossil fuels S Burning of fossil fuelsS Precious metal mining S Wood pulping & paper manufactureS Compact fluorescent globes S Metal refining and smeltingS Felt & hat making
Transport mechanisms Mercury Sulphur dioxideS 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 groundS 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
Persistence & Sinks Mercury Sulphur dioxideS Highly persistent S Low/medium persistenceS Exposure via ingestion S Exposure via inhalationS Bioaccumulates S Wetlands, lakes,S Sinks are sediments oceans and organisms S Absorbed by soils and plants
Human health effects Mercury Sulphur dioxideS 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
Human Health Effects Mercury Sulphur dioxideS 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, causesS 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.
Environmental health effects Mercury Sulphur dioxideS 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.
Practise question 8:S Mercury can be particularly hazardous to human and animal health because of bioaccumulation. BioaccumulationA. Is caused by excessive exposure to mercury in the airB. Occurs because the person or animal is allergic to mercuryC. Is due to synergism between mercury and another pollutant in the ecosystemD. Occurs because the rate of intake exceeds the rate at which the body can remove it.
Practise question 9:S Bioaccumulation of mercury is most likely to occur inA. Aquatic organismsB. Animals high up in the food chainC. Sediment in lakes containing mercuryD. Animals that are low in fat, and so are unable to store the mercury, which is fat soluble.
Management strategies Mercury Sulphur dioxideS Minimise use in extracting S Use low-sulphur coal & smelting S Change extraction processS Replace with alternatives S Reduce fugitive emissionsS Reduce fugitive emissions S Control devices (scrubbers, tallS Pollution control devices? stacks, acid-plants)
Endocrine disrupting chemicalsS “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
Section B: Short answerS 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
Section B: Short answerS 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)
Samples are taken ateach of locations A, B, Cand D.Each sample is tested forthree pollutants I, II, andIII.
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.
Human Health Effects Methods of exposure Pathways of pollutants Dosage Toxicity and LD50 S
Exposure : Dosage : the Toxicity : aHow much of a amount of a measure of thepollutant an chemical influenced by harm aorganism is exposed absorbed per substance canto over a specific unit body cause anperiod 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
Methods of ExposureS “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)
Measuring pollutantsS Grams (or mg) per unit volume (air or water)S For example, g/litre or mg/litre or g/m3S Gases measured in ppm or ppbS Emissions can also be measured per unit time (eg. g/min)S Check for SALT on your graphs (Scale, Axes, Labels, Title)
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 mgB. 280 mgC. 350 mgD. 600 mg
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%
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 southB. 3 minutes at 1 km southC. 4 minutes at 1 km northD. 5 minutes at 8 km north
Pathways of pollutantsS 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
DosageThe dosage someone receives will depend on the:S Rate of respiration/ingestion/absorptionS Length of exposureS Frequency of exposureS Concentration of pollutantS Physical, chemical and biological properties of the pollutanthttp://www.biology.arizona.edu/chh/problem_sets/toxicology/toxicology.html
ToxicityWhich pollutant is more harmful?S LD50 of 60mgS LD50 of 35mgS LD50 of 10mgS LD50 of 5mg
Environmental health effects Acid rain Acidification Eutrophication Bioaccumulation & Biomagnification S
Acid rain http://www.abc.net.au/science/artichttp://en.wikipedia.org/wiki/Acid_rain les/2010/06/28/2938845.htm
Bioaccumulation & Biomagnification
Section B: Case studyS Name a pollutant you have studied this yearS 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 sinkS (2 + 2 + 3 + 2 = 9 marks)
Section B: Case studyS 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)
Section B: Case studyS Evaluate the effectiveness of this strategy using evidence. (3 marks)TOTAL for your case study2 + 2 + 3 + 2 + 2 + 2 + 2 + 3 = 18 marks/9020% of the exam
Monitoring is not a strategy!S Monitoring or measuring the pollutant is NOT a strategy that reduces emissions or exposureS Research, by itself, cannot reduce emissions or exposureS Education, by itself cannot reduce emissions or exposureS 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
Exam Preparation Preparing yourself Materials you should take Using your reading time Writing time beginsMarks are a guide to answers S
Preparing yourselfS get enough rest and sleepS eat sensibly, dont skip meals or try to fill up on snacks - active brains need a balanced dietS check on the starting time and allow plenty of time to get to your examination centreS check that you have everything you need - make yourself a list
Materials you should takeS 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 timeS clear (transparent) rulerS two pencils (with extra lead or a sharpener)S eraserS scientific calculator (either with new batteries or a back up scientific calculator)
Using your reading timeS 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
Using your reading timeS 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.
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.
Marks are a guide to answersS 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.
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