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ACID DEPOSITION PowerPoint Presentation
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ACID DEPOSITION

ACID DEPOSITION

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ACID DEPOSITION

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  1. ACID DEPOSITION • the wet or dry deposition of acid • “Acid rain” 1. Acid rain refers to all types of precipitation--rain, snow, sleet, hail, fog--that is acidic in nature 2. precipitation that is polluted by sulphur dioxide (SO2) and nitrogen oxides (NOX)

  2. Link to the Fossil Fuels • Combustion of fossil fuels • sulphur is harmful in excessive amounts • Much of Europe and North America are suffering from sulphur deposition that exceeds critical loads as a result of the large amounts of such compounds generated by human activity • http://imgur.com/a/CnXGL

  3. Key concepts: • The amount of CO2 in the atmosphere is increasing Currently 30% higher than since last 650,000 years Mauna Loa , Hawaii (13,677 ft = 4169 m)

  4. Reactions to convert to acid take place in ~2 days - travel 1000 miles Down wind - Acid rain Dry Dep. vs Wet Dep. Dry Deposition 50 % of total Can react with plants - strip nutrients Tree dieback Acid Deposition

  5. Acid Rain and Trees

  6. Forests affected by Acid Rain Northeast US Canada Northern Europe Asia

  7. Acid Rain and Buildings Many buildings are made of concrete and or stone These compounds act as bases and react with acid The building technically “weathers” very fast, or Non technically “crumbles”

  8. Europe The US Capitol

  9. Acid Rain Damage to Buildings and Cultural Monuments • In urban areas, acid deposition is rapidly deteriorating buildings, sculptures, paintings, metal, glass, paper, leather, textiles and rubber • European officials say that "ancient buildings and sculptures in a number of cities have weathered more during the last 20 years than in the preceding 2,000" (Green Issues, pg. 16). • Sandstone, limestone and marble are the easiest victims of sulphur dioxide because they contain calcium, and when the two react they form gypsum which washes away easily with rainfall. • Paper and textiles are also damaged by SO2 and NOx pollution because paper absorbs these gases and become more and more brittle as they absorb more pollutant. "About 5% of the British Library’s collections are thought to be seriously damaged by sulphur-contaminated air" (Green Issues, pg. 16) • Bridges are corroding at a faster rate • in 1967,the bridge over the Ohio River collapsed killing 46 people-the reason was corrosion due to acid rain • 70,000 bridges across the country are classified as structurally deficient

  10. How atmospheric acids form 1. S + O2-->SO2 and N + O2-->NO2 and CO2 2. In the atmosphere, sulphur dioxide reacts with oxygen to produce sulphur trioxide gas: 2SO2 + O2-->2SO2 3. Some of this sulphur trioxide dissolves into water droplets in the atmosphere to produce tiny beads of sulphuric acid i. SO3+ H2O-->H2SO4 ii. NO3 + H20 –> H2NO4 iii. CO2 + H20  H2CO3

  11. What causes the problem • Public power generation. These are, in general, large plants burning fossil fuel to generate electricity. • Commercial, Institutional, Residential Combustion Plant • Industrial Combustion Plant and Processes with Combustion - pulp mills, metal smelters (when metal sulfide ores such as lead sulfide are roasted or smelted to convert the metal ore to free metal), refineries, heating boilers. • Extraction and Distribution of Fossil Fuels • Road Transport • Natural Sources - volcanic eruptions, oxidation of sulfur-containing by-products of decomposition of organic matter

  12. Other hazards of Sulphur pollution: Sulphurous smogs 1. Produced by high output of SO2, converted to acids on contact with atmospheric moisture. Very prevalent in Europe and North American cities during first part of 20th Century 2. London. 4-10th December 1952: Cold, high-pressure conditions trapped coal smoke in foggy air. Output of smoke increased by cold. Sulphuric acid droplets resulted in pH estimated as 1.4 to 1.9: as acidic as car battery acid. Visibility reduced to 5m at times. Smog lasted for 5 days, eventually extending over 50km radius. Approx. 4,000 people died as result of inhaling pollution, mainly old and sick and those with chest problems.

  13. Donora, USA: October 1948: industrial town of 14,000, with zinc smelter, steel mill, and sulphuric acid plant, all of which introduced sulphuric acid into atmosphere. Anticyclonic conditions trapped emissions, which continued to be produced. Air became highly acidic, with sickening smell of sulphur. Over five day period, over half of population suffered ill effects, and 22 died

  14. Effects on Ecosphere 1. Terrestrial Ecosystems i. Acid rain damages the protective waxy coating of leaves and allows acids to diffuse into them ii. interrupts the evaporation of water and gas exchange so that the plant no longer can breathe iii. This stops the plant's conversion of nutrients and water into a form useful for plant growth and affects crop yields. (1) acid precipitation destroys, overall, $1.3 billion annually in the eastern part of the nation (2) $1.75 billion yearly in forest damage, $8.3 billion in crop damage in the Ohio River basin alone by about the year 2000 2. $40 million in health costs in the State of Minnesota

  15. Aquatic Ecosystems i. Aquatic plants grow best between pH 7.0 and 9.2 ii. As acidity increases submerged aquatic plants decrease and deprive waterfowl of their basic food source. iii. At pH 6, freshwater shrimp cannot survive. iv. At pH 5.5, bottom-dwelling bacterial decomposers begin to die and leave undecomposed leaf litter and other organic debris to collect on the bottom...water becomes malnourished v. This deprives plankton--tiny creatures that form the base of the aquatic food chain--of food, so that they too disappear vi. Below a pH of about 4.5, all fish die. vii. Most of the frogs and insects also die when the water reaches pH 4.5.

  16. Key concepts: • 2. The chemistry of the ocean is dependent on the chemistry of the atmosphere

  17. Key concepts: • 3. Water becomes more acidic the more CO2it contains. CO2 reacts with H20 to produce: bicarbonate (HCO3) hydrogen (H): makes ocean more acidic

  18. Key concepts: 4. Increased ocean acidity affects marine organisms’ abilities to make and keep their hard parts. Hard parts = calcium carbonate (CaCO3) shells, skeletons, etc.

  19. Key concepts: 4. Increased ocean acidity affects marine organisms’ abilities to make and keep their hard parts. Hard parts = calcium carbonate (CaCO3) shells, skeletons, etc. • Many marine organisms have CaCO3 hard parts • They use their ATP (energy) to make their hard parts using calcium (Ca) and carbonate (CO3) they get from the sea water

  20. Key concepts: 4. Increased ocean acidity affects marine organisms’ abilities to make and keep their hard parts. Hard parts = calcium carbonate (CaCO3) shells, skeletons, etc. • Many marine organisms have CaCO3 hard parts • They use their ATP (energy) to make their hard parts using calcium (Ca) and carbonate (CO3) they get from the sea water • BUT, hydrogen also naturally reacts with CO3

  21. Key concepts: 4. Increased ocean acidity affects marine organisms’ abilities to make and keep their hard parts. Hard parts = calcium carbonate (CaCO3) shells, skeletons, etc. • Many marine organisms have CaCO3 hard parts • They use their ATP (energy) to make their hard parts using calcium (Ca) and carbonate (CO3) they get from the sea water • BUT, hydrogen also naturally reacts with CO3 • The more acidic the ocean, the more CO3 reacts with hydrogen, and the LESS CO3 left for marine organisms to convert into their hard parts

  22. Key concepts: 4. Increased ocean acidity affects marine organisms’ abilities to make and keep their hard parts. Hard parts = calcium carbonate (CaCO3) shells, skeletons, etc. • Many marine organisms have CaCO3 hard parts • They use their ATP (energy) to make their hard parts using calcium (Ca) and carbonate (CO3) they get from the sea water • BUT, hydrogen also naturally reacts with CO3 • The more acidic the ocean, the more CO3 reacts with hydrogen, and the LESS CO3 left for marine organisms to convert into their hard parts • “Battle” for carbonate! • Organisms must use more energy or make less hard part material • Existing hard parts dissolve (chemical reaction goes “the wrong way”)

  23. Ocean acidification: Impacts on individual marine organisms • Thinner, smaller and weaker shells in shellfish • Especially larval stages, which already have thin shells Mussels Mussel larva Normal Really acidic Acidic Gaylord et al. 2011

  24. Ocean acidification: Impacts on individual marine organisms • Reduced hearing ability in anemone fish (clown fish) larvae • Deformed morphology of CaCO3 fish ear bones (otoliths)? • Disruption of acid-base balance in neuro-sensory system? • Fitness effect: lower survival due to higher predation. Normal Acidic Simpson et al. 2011

  25. Ocean acidification: Impacts on individual marine organisms • Non-calcifying marine algae: Increased photosynthesis and growth • Lower pH means more dissolved CO2 for photosynthesis to fuel growth • Fitness effect: higher survival and pop’n growth Photosynthesis Growth Chen & Durbin 1994 Lots Little Lots Little Amount of dissolved carbon

  26. Ocean acidification: Impacts on ecological communities • Tropical Oceans Predictions: • Corals will become increasingly rare • Algae will become more abundant • Because coral reefs support so many animals, biodiversity will decline Hoegh-Guldberg et al. 2007

  27. Could this cause coral extinctions? • A distinct possibility if ocean acidification continues High coral growth Earth’s two most recent mass extinction events Both associated with high CO2 levels First modern corals Million years ago Present Veron 2008

  28. Borrowed Heavily From: http://oceanacidification.msi.ucsb.edu/resources/educators/CrowWhite_OA_Lecture.ppt/view