CYCLES AND POLLUTION

Transcription

1 CYCLES AND POLLUTION

2 WATER PROPERTIES Universal Solvent: dissolves many substances Polar Molecule: the shared electrons of each water molecule are not evenly spread throughout the molecule ( + and - ends) Substances that dissolve in water have partial charges that interact with water molecules Like dissolves like

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4 ACIDS Donates hydrogen ions (H + ) to form hydronium ( H 3 O + ) ions (H 2 O + H + à H 3 O + ) Turn blue litmus paper red Conduct electricity

5 BASES Contains hydroxide ions (OH - ) or reacts with water to form hydroxide ions Bitter taste Slippery Conduct electricity Turns red litmus paper blue

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7 ph SCALE The measure of the hydronium ion (H 3 O + ) concentration in a solution Range is from 0-14 < 7 is acidic H 3 O + > OH - > 7 is basic OH - > H 3 O + 7 is neutral OH - = H 3 O +

8 NEUTRALIZATION REACTIONS A reaction between hydronium ions and hydroxide ions to form water molecules The resulting solution is more neutral than either of the reactants Strong acids and bases react to form water and salt Example: KOH + HNO 3 KNO 3 + H 2 O

9 Dissolution Solute: A substance being dissolved in a solution Solvent: The liquid that a substance is being dissolved in To help solutes dissolve in solvents Increase temperature Stir the solution Increase the surface area of the solute

10 WATER CYCLE Evaporation: Solar energy hits surface water and causes water molecules to go from l à g Transpiration: Plants lose moisture to atmosphere Condensation: Water vapor rises, cools and condenses into tiny water droplets (clouds) Precipitation: clouds cool, condense and release moisture Groundwater: Water filters into ground. Surface Water: any standing water on the surface of Earth. Oceans, lakes, rivers, etc.

11 WATER POLLUTION Pollution: the contamination of the air, water or soil Most water pollution can be traced to industrial waste, agricultural fertilizers and every day human activities: Soap Sewage Sediment Potable: safe to drink Non-potable: not safe to drink

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13 FERTILIZERS Applied to farms and lawns; washed away by rain and end up in stream, rivers, lakes or ponds Contain nitrate ions which encourage the growth of bacteria and algae

14 ARTIFICIAL EUTROPHICATION An increase in the amount of nutrients (from fertilizers carried in runoff) 1. Excess nitrates (fertilizers) released in water 2. Algal bloom 3. Algae die and fall to bottom 4. Bacteria feed on dead algae 5. Bacteria use up available oxygen in water 6. Fish and aquatic wildlife die

15 BIOMAGNIFICATION 1. Fertilizers and/or pesticides applied by agriculture and homeowners 2. Washed by rain into streams, lakes or ponds 3. Ingested by fish and aquatic wildlife 4. Passed along the food chain 5. Accumulate up the food chain

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17 DDT Pesticide that was used to control mosquitoes Ended up in runoff and was ingested by aquatic life Birds like pelicans and osprey ate fish which had ingested DDT Caused the eggs of these birds to become thin and fragile Bird population numbers dropped because young did not survive Banned from the US

18 EARTH S ATMOSPHERE Troposphere: Layer closest to Earth; where weather occurs; densest because of pressure of all other layers Stratosphere: Layer above troposphere; contains the ozone layer Mesosphere: Coldest layer Thermosphere: Warmest layer Exosphere: Outermost portion of thermosphere

19 AIR POLLUTION Comes in many forms from individual molecules to clumps of dust called particulates Combustion of fossil fuels produces the most air pollution releasing 1. Energy 2. Carbon dioxide 3. Water Vapor 4. Sulfur Oxides 5. Nitrogen oxides Natural processes, such as volcanoes and forest fires, also contribute to air pollution by releasing greenhouse gases

20 PHOTOCHEMICAL SMOG Thick, brownish haze formed when certain gases in the air react with sunlight Major sources = automobiles Burning of fossil fuels releases hydrocarbons and nitrogen oxides Nitrogen oxides react in sunlight to produce ozone the major chemical in smog Though ozone is beneficial to us in the stratosphere, it is harmful when it is in the troposphere Health effects: lung problems, asthma, breathing conditions

21 INDOOR AIR POLLUTANTS Dust Pet Hair Cigarette Smoke Perfumes/Air Fresheners Asbestos Radon Carbon Monoxide: forms when wood, coal, oil or gas are burned Colorless, odorless, and LETHAL!

22 OZONE DEPLETION Good ozone: in stratosphere, protects from UV rays Chlorofluorocarbons (CFCs) contain chlorine and fluorine CFCs react with ozone and block the cycle that absorbs ultraviolet rays CFCs are stable and remain in atmosphere for a long time Ozone recovery??? Hasn t thinned since 98 Expected to take several lifetimes

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24 CARBON CYCLE Present in atmosphere as carbon dioxide Producers take in CO 2 from atmosphere during photosynthesis. Use C from CO 2 to produce other carbon molecules (sugars, starches, cellulose and proteins) Sunlight = Energy source Consumers break down those molecules into simpler forms. Consumers release water and CO 2 as waste products. Plants produce the O 2 consumers take in. Fossil fuels contain carbon BUT they are not part of cycle unless brought to the surface through combustion.

25 Photosynthesis & Respiration Photosynthesis: Plants take in carbon dioxide and water to produce oxygen and glucose CO 2 + H 2 O à C 6 H 12 O 6 + O 2 Respiration: Both plants and animals respire; they take in glucose and oxygen to produce carbon dioxide and water C 6 H 12 O 6 + O 2 à CO 2 + H 2 O

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27 HUMAN ACTIVITIES AFFECT THE CARBON CYCLE Burning of fossil fuels Deforestation Overpopulation Cattle Production

28 Factors in the Environment Biotic Factors: Living things that shape an ecosystem Plants, animals Abiotic Factors: Nonliving things that shape an ecosystem Temperature, oxygen

29 NITROGEN CYCLE In atmosphere as N 2 called free nitrogen N 2 cannot be utilized by most organisms Nitrogen Fixation: process of changing N 2 gas into a usable form. Done by bacteria called nitrogen fixing bacteria. Nitrogen can also be fixed by lightning! Bacteria live in soil and in the root nodules of certain plants called legumes. Examples: clover, alfalfa, beans, peas, peanuts.

30 NITROGEN CYCLE Decomposers break down compounds in animal waste and in bodies of dead organisms Return the nitrogen back to the soil Denitrification: denitrifying bacteria can eventually break down the nitrogen compounds completely (return Nitrogen back into atmosphere)

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32 GREENHOUSE EFFECT Greenhouse gases in the atmosphere allow sunlight to reach Earth s surface but prevent the heat (infrared radiation) from escaping back into space Without it Earth would be much colder Greenhouse gases Water Vapor Carbon Dioxide Methane Other Gases

33 GLOBAL WARMING An increase in Earth s temperature due to an increase in greenhouse gases Since the 1800s CO 2 has increased, by 2020 it will be 2x it present level Due to the combustion of fossil fuels

34 EFFECTS OF GLOBAL WARMING Ice caps/glaciers melting Sea levels rise More severe storms Change in climate patterns

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36 LAND POLLUTION Trash Lead Hazardous chemicals Landfills Open dumps

37 LAND USE Agriculture Business Development Mining

38 THE 3 R S Reduce create less waste. Example: Composting Reuse find another use Recycle reclaim raw materials to create new products Biodegradable substance that can be broken down and recycled by bacteria and other decomposers (naturally).

39 HOW CAN YOU HELP?? Government Regulations Alternative Energy Sources Conserve Energy Carpool Conserve Water

40 WHAT IS A BROWNFIELD SITE? Many plots of land in this country have had a previous use, and are occasionally referred to as a brownfield sites. Some of these brownfield sites have been contaminated in the past by industries such as: gasworks tanneries chemical works landfills former mining sites asp&h=259&w=173&sz=10&hl=en&start=15&tbnid=0718QbMNVdFIIM:&tbnh=112&tbnw=75&prev=

41 WHAT IS A BROWNFIELD SITE? Beneath the tarp in the photo is soil contaminated by dioxin and PCBs Superfund sites are those Brownfield sites identified by EPA to be cleaned up by law: Comprehensive Environmental Response, Compensation, and Liability Act

42 WHAT IS A BROWNFIELD SITE? Many Brownfield sites are located in cities that were once large industrial areas. Now these cities are running out of land and need to reclaim these sites and make them safe for people to live. Just south of Detroit

43 WHAT CAN BE DONE? Locate contaminated land Inspect potentially contaminated land Determine who is responsible for the contamination & cleanup

44 WHAT CAN BE DONE? Declare land contaminated Make sure cleanup takes place Consider wildlife that has occupied brownfield sites Keep a registry of contaminated sites impact_assessment.html&h=258&w=430&sz=56&hl=en&start=5&tbnid=yc2- pklppezyqm:&tbnh=76&tbnw=126&prev=

45 LOCATE & INSPECT CONTAMINATED SITE Brownfield sites are identified by several methods: Review historical use of the site Collection of subsurface soil samples Check contamination of buildings or other structures on the site

46 IDENTIFICATION OF RESPONSIBLE PARTY Environmental Forensics has the potential to prove who is to pay for the cleanup

47 STEPS IN REMEDIATION Reduce an immediate hazard Analyze the contamination Determine how the hazard has affected the population around the site Identify how the site will be fixed keeping in mind resources available and how it will be used Remediation and/or confinement then takes place Monitor and/or restrict use of the site if necessary

48 ANALYZE THE CONTAMINATION Complicated Task because it involves: A variety of soil types Ground and surface water A variety of contaminants and how they change over time Compilation of a 3-D map of the site History of site use

49 WHAT CAN BE DONE?

50 WHAT CAN BE DONE? Hazardous wastes from Brownfield sites can be incinerated The problem -- Production of heavy metal emissions such as Hg, As, and Pb Organic pollutants such as dioxin

51 CLEANUP Depending on how and where hazardous substances are dispersed, you may need to use an intrusive collection method (pumping, stripping, removing, or excavating) to consolidate environmentally contaminated material for treatment or disposal These types of operations will usually result in the highest chemical exposure to employees, and require the most physical activity, equipment, and planning.

52 YOUR BROWNFIELDS ASSIGNMENT Find the registry of Brownfield sites Report the site name, location, acreage, and past use Based on the past use you reported, determine a possible contaminant Research that contaminant does it typically pollute soil, air or water? Determine what you would do if you were to be in charge of cleanup. Where might you suggest testing? Be specific! Try using Google Earth to determine what else is in the area that could be contaminated too. How could the contaminant have affected wildlife or humans in the area?