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Topic 4.0 – Transport of Materials in the Environment

Topic 4.0 – Transport of Materials in the Environment. I. Transport of Materials. A. Transport in Air. Chemical is released. Dispersion (particles scatter in air). Deposition of chemical in soil or water. I. Transport of Materials. A. Transport in Air Factors affecting distribution:

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Topic 4.0 – Transport of Materials in the Environment

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  1. Topic 4.0 – Transport of Materials in the Environment

  2. I. Transport of Materials A. Transport in Air Chemical is released Dispersion (particles scatter in air) Deposition of chemical in soil or water

  3. I. Transport of Materials A. Transport in Air • Factors affecting distribution: • Wind – direction and distance of travel • Precipitation – will deposit chemical where rain/snow occurs

  4. Where is the healthiest place to live around: Fort McMurray? Sherwood Park? Grande Prairie? Calgary? INFO : Particulates can land 30 – 300 miles away from the source! Does this change your answer?

  5. Does this information change your answer?

  6. I. Transport of Materials B. Transport in Surface Water • Surface water – fast moving water (streams, rivers) or standing water (sloughs, lakes) • Solutions that dissolve easy travel far in surface water

  7. Which will carry a toxin further? Where will it be more concentrated?

  8. I. Transport of Materials C. Transport in Groundwater Groundwater – water beneath the surface layer of soil • Slower movement of water than surface • How packed the soil is dictates how fast water flows through this region (usually downwards) • Packed soil = pores which are not connected = slow water movement • Permeable soil – has pores which are connected and allows quick water movement

  9. I. Transport of Materials C. Transport in Groundwater • Gravel – high porosity (permeability) - allows water to flow through quickly • Sandy soil – has med-high porosity- • Clay – low porosity – little water movement

  10. I. Transport of Materials D. Transport in Soil • Leachate – water which has dissolved chemicals in the soil and carries to the groundwater • This can contaminate our ground water and drinking water sources • Aquifier – a source of ground water that has been naturally filtered but can contain toxins due to leaching

  11. I. Transport of Materials • D. Transport in Soil Common Sources and Contaminants

  12. II. Changing Chemical Concentrations Five mains ways of reducing chemical concentrations: • Dispersion – particles spread out from where they were released • Dilution – adding water or air to a chemical/toxin to reduce the concentration

  13. 3) Biodegredation– using living organisms to break down substances Ex. Bacteria, fungi, earthworms >anaerobic – when bacteria degrade without oxygen -in landfill sites >aerobic – when bacteria require oxygen to break down toxins • To speed up biodegredation: • Warm temperatures • Planting plants • Use bioreactors • Lots of oxygen

  14. II. Changing Chemical Concentrations • Phytoremediation “phyto” means plants “remediation” means cure • Using plants to clean the soil of metals or toxins (they absorb the toxins) • Photolysis “photo” means light; “lysis” means break • Using the sun to break down compounds Ex. Plastics Ex. NO2 can form O3

  15. Introduction Qs. • What are the 5 methods of reducing toxin concentration? • Why do we want to reduce the concentration of toxins? • How can we dilute a toxin? • What is phytoremediation? • Would clay or gravel-soil remove more toxins? Why? • What are the conditions that affect how far an emission is deposited on the ground?

  16. Which is a better method of garbage disposal? Why? Sanitary landfill or incinerator?

  17. Waste and Toxin management • Sanitary landfill – landfill with a clay base and plastic liner to prevent leachate from entering our water table • Is covered daily with dirt to avoid scavengers and litter movement • Is “flared off” – the anaerobic biodegradation produces methane, so it is piped to surface and burned off • Incinerator – burning of waste to break down toxic compounds ; can contribute to air pollution

  18. Waste and Toxin management Wastewater management • Sewage – waste water from home • Septic tank – underground container where bacteria break down materials before released to soil • Sewage treatment plant – treats wastes before re-entering environment • Effluent – treated wastewater which is released to river or lakes

  19. Storm sewers – leads directly to river when sewers are overfilled • Contain gas, oil, etc from street

  20. Wrap-Up Notes • persistent vs. non-persistent • Persistent – toxins that remain in the environment for long periods of time • Point source vs. non-point source • Point source – source of pollution is from one identifiable source Ex. Sewage effluent pipe • Non-point source – exact location of source of pollution is not identifiable Ex. Smokestacks release air pollutants that travel 100’s of km in any direction

  21. Wrap-Up Notes • NIMBY – not in my back yard • Where citizens do not support development due to it being too close to their community. • Examples: • Electrical powerlines • Landfills • Chemical plants

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