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Science 9

Science 9. Aim: How do we determine water and air quality. Agenda. Science Sizzler Water Quality notes Homework worksheets Next class. Dissolved Oxygen. Essential for the health of aquatic life The level of dissolved oxygen in water depends on: Temperature

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Science 9

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  1. Science 9 Aim: How do we determine water and air quality

  2. Agenda • Science Sizzler • Water Quality notes • Homework worksheets • Next class

  3. Dissolved Oxygen • Essential for the health of aquatic life • The level of dissolved oxygen in water depends on: • Temperature • Turbulence due to wind, or speed of moving water • Amount of photosynthesis by plants and algae in water • The number of organisms using up the oxygen. • 5 milligrams per litre (5ppm) of dissolved oxygen will support most organisms that live in lakes and streams.

  4. Phosphorous and Nitrogen • An increase in P and N can lead to a decrease in dissolved oxygen. • High concentrations of P and N can lead to some problems. • Cause increased growth of algae and green plants. • Bacteria increase, using up O in the water.

  5. Pesticides • Mixing of different pesticides in bodies of water may form a much more toxic or poisonous substance. • Toxicity describes how poisonous a substance is. • Most pesticides used today are designed to break down after a certain time passes.

  6. Measuring Toxins • Toxins are substances that produce serious health problems or death when introduced into an organism. • Measurement used to compare toxins is called LD50, where LD stands for lethal dose, and 50 stands for 50%. • LD50 is the amount of substance that causes 50% of a group of test animals to die.

  7. Heavy Metals • Heavy metals have a density of 5 g/cm2or more. • This means that they are five or more times heavier or denser than water. (Cu, Pb, Zn, Hg, Cd, and Ni) • These metals occur naturally. • Found in a lot of everyday items. (batteries, tires, gas, paints, pipes, thermometers, and fertilizer.)

  8. Monitoring Air Quality What is our air made of?  Nitrogen (78%), Oxygen (21%), Argon (less than 1%)  Trace amounts of CO2, Hydrogen, and Neon

  9. Monitoring Air Quality Irritated throat and stinging eyes may indicate poor air quality

  10. Monitoring Air Quality Determining Air Quality: 1) Measuring the level of pollutants in the air 2) Estimating the amount of emissions from potential pollution sources

  11. Monitoring Air Quality Major Air Pollutants  SO2 = Sulpher dioxide  NOx = nitrogen oxides CO = Carbon Monoxide  O3 = ozone (ground level)

  12. Monitoring Air Quality SULFUR DIOXIDE (SO2)  forms when sulfur combines with oxygen  major source = industrial processes (ex. Oil & Gas)  forms smog and acid rain  can result in throat and lung problems and irritated eyes

  13. Monitoring Air Quality DEALING WITH SULFUR DIOXIDE (SO2) Many industrial plants use “scrubbers” to reduce SO2emissions These scrubbers use LIMESTONE (calcium carbonate) to convert the pollutant to produce GYPSUM – a useful material in manufacturing (“GypRock” or drywall)

  14. Monitoring Air Quality NITROGEN OXIDES (NOX)  NOX = Means mixture of NO and NO2  Form from the combustion in vehicles and industrial processes  Can affect respiratory system and eyes

  15. Monitoring Air Quality CARBON MONOXIDE (CO) • “The Silent Killer” = colourless and odorless • If there isn’t enough oxygen available during combustion, carbon monoxide forms instead of carbon dioxide • Sources can include: vehicles, natural gas, burning wood, industrial processes  Can cause headaches, sleepiness, brain damage and death

  16. Monitoring Air Quality OZONE (O3) Ozone in the upper atmosphere protects the Earth’s surface from harmful ultraviolet light BUT on ground level, ozone is a harmful pollutant

  17. Monitoring Air Quality GROUND-LEVEL OZONE (O3) • Odorless and colorless gas • Forms from reactions between oxygen, nitrogen oxides and compounds called volatile organic compounds (VOCs) in the presence of sunlight • Sources: fuel combustion and industrial processes

  18. Monitoring Air Quality GROUND-LEVEL OZONE (O3) • A major issues in the summertime in large cities • Very harmful to lungs, especially for “at-risk people” (elderly, children, people with lung diseases)

  19. Is Carbon Dioxide a Pollutant?? No, because it is naturally present in the air (many organisms exhale CO2 into the air)

  20. BUT… The amount of CO2 is increasing in our atmosphere, which is cause for great concern

  21. Why are CO2 levels increasing? Since the Industrial Revolution, CO2 levels in the atmosphere have been rising  burning of fossil fuels  exhaust from vehicles  any combustion reaction

  22. The Increase of CO2 and the GREENHOUSE EFFECT The Earth is like a Greenhouse: The atmosphere lets the sunlight in and traps some of the energy inside while letting some energy back out

  23. GREENHOUSE EFFECT Some gases in our atmosphere act like the glass of a greenhouse – trapping the sun’s energy in. This keeps the Earth at temperatures that allow life to exist.

  24. These gases are called GREENHOUSE GASES and include:  Water Vapour, CO2, Methane and NOx

  25. Human activities, such as burning of fossil fuels, contribute to an enhanced greenhouse effect Keeps more of sun’s energy (and warmth) in the atmosphere

  26. Impacts of a Warming Earth • Increased Temperatures • More Violent Storms • Flooding of Coastal Areas • Melting of Glaciers and Ice Caps • Potential Increase of Disease Spread

  27. The Ozone Layer Although ground-level ozone (O3) is considered a pollutant and can be very harmful, ozone in our atmosphere is essential This ozone is found 15-50km above the Earth’s surface

  28. The Ozone Layer The ozone layer, high up in our atmosphere, absorbs dangerous Ultraviolet light from the sun

  29. The Ozone Layer Over the years, the ozone layer has become thinner – allowing more UV light in.

  30. The Ozone Layer Scientists have discovered that the thinning of Ozone is due to our use of chemicals called CHLOROFLUOROCARBONS (CFCs)

  31. The Ozone Layer What are CHLOROFLUOROCARBONS (CFCs)?  Chemicals used in many applications, including: refrigerators and aerosol cans  The UV light breaks down CFCs into chlorine molecules, which destroy ozone  Many countries have recognized the danger of CFC use and have reduced their usage

  32. Transport of Chemicals in our Environment Many pollutants end up far from where they are produced… how do they spread?

  33. Transport of Chemicals in our Environment Transport of Substances in the Air:  3 Stages: 1) Release of the Chemical at the Source 2) Dispersion of the Chemical in the atmosphere 3) Deposition of the Chemical in Soil or Water

  34. Transport of Chemicals in our Environment Factors that Impact Air Transport of Chemicals  Presence of Wind  Wind Speed  Rain (chemical will be brought down to soil/water closer to where they originated)

  35. Transport of Materials in Groundwater Chemicals soak into Soil (zone near the surface)  the spaces between soil grains contain water and air As chemicals move deeper, it enters Groundwater  the spaces between soil grains contain water only SOIL GROUNDWATER

  36. Transport of Materials in Groundwater The highest point of groundwater is called the WATERTABLE SOIL GROUNDWATER Figure 3.3 (Pg 239)

  37. Transport of Materials in Groundwater Once chemicals reach the groundwater, they have the potential to become quickly concentrated and disperse …but relatively slowly. Groundwater can move 1 metre per year to 1 metre per day (much slower than rivers/streams)

  38. Movement of Groundwater: Pores = tiny spaces between soil grains

  39. Movement of Groundwater: Pores = tiny spaces between soil grains • Tightly Packed Soil = the pores aren’t connected and water cannot move easily • Permeable Soil = pores are interconnected, water can flow and pollutants can travel more

  40. Transport of Chemicals in Surface Water Substances that enter surface water can either:  Dissolve and… … disperse quickly … may be carried a long way  Not Dissolve and… … attach to soil grains and sink to the bottom … become concentrated near the source

  41. Transport of Chemicals in Soil What does water do when it hits the soil? • some evaporates • some runs onto the street or into a stream • some soaks into soil and is taken up by plants • some soaks into soil and moves downward = dissolving chemicals and bringing them down with it (“LEACHATE”)

  42. Transport of Chemicals in Soil Chemicals in the soil can be absorbed by organic materials… slowing the chemicals movement. & Hazardous Materials can a be changed in the soil by chemical reactions (ex. acids being neutralized)

  43. Techniques that Affect Chemical Concentrations in our Environment Dispersion • Scattering of a substance away from its source Dilution • Reduces the concentration of a pollutant by mixing the substance with large quantities of air or water Fast-Flowing Water Can Do Both Of These (but not always a good enough job)

  44. How does nature use living organisms to help clean the environment?

  45. BIODEGRADATION • Breakdown of materials by organisms such as earthworms, bacteria, and fungi By breaking up organic substances, including many pollutants, decomposers help return usable nutrients to the soil Bioplastics, designed to degrade into an ecofriendly mix of water, carbon dioxide, and biomass.

  46. BIODEGRADATION • Many micro-organisms (ex. bacteria) use existing organic compounds for food Some bacteria can… … do this only in environments with oxygen = this is referred to as AEROBIC BIODEGRADATION …function in environments without oxygen… this is referred to as ANAEROBIC BIODEGRADATION

  47. Factors affecting Biodegradation • Temperature, moisture, pH, oxygen supply, and available nutrients. • Phytoremediation • A technique used to reduce harmeful chemicals in soil or groundwater using green plants. • Photolysis • The breakdown of substances from exposure to sunlight.

  48. Hazardous chemicals affect living things Biomagnification: The increase in concentration of a chemical or element as it moves up the food chain Ex. Mercury Bacteria Algae  Invertebrates  Fish  Humans or other meat eating organisms. If you collect enough mercury in your system it could make you sick.

  49. Oil Spills impact on environment • Crude oil is a mixture of many chemicals. • Floating algae killed • Decrease in dissolved oxygen killing some organisms. • Loss of foods, and toxic effects. • Physical deformations in some organisms if not killed outright. • Oily feathers and fur made organisms susceptible to cold weather. • Reduced commercial fishing done by companies.

  50. Hazardous Household Chemicals Many products we use to maintain our houses, cars, and yards have the potential to harm our environment. These Include: Cleaners Hygiene Products Pet-Care Products Paint Pesticides Automotive Fluids

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