Acid Precipitation Section 12.3

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Acid PrecipitationSection 12.3

• Objectives
• Explain causes of acid precipitation.
• Explain effects of acid precipitation.

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Intro

1. Rainfall downwind
2. Acid precipitation and cars

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What Causes Acid Precipitation?

• Acid precipitation any form of precipitation
  that contains a high concentration of acids
• Caused by burning fossil fuels
• Releases oxides of sulfur and nitrogen into the
  air (SO2 and NO2)
• These gases combine with water vapor in the
  atmosphere, forming sulfuric acid and nitric acid.

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pH power of hydrogen

• Acids pH lt 7
• Bases pH gt 7
• Pure water pH 7.0
• Normal rain pH about 5.6
• Acid precipitation pH lt 5.0
• Varies by location
• Eastern Europe 4.3-4.5
• Rest of Europe 4.5-5.1
• Eastern U.S. 4.2-4.8 (Lake Ontario and Lake
  Erie 4.2)

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pH Scale
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Effects on Soil and Plants

• Drop in pH of soil (acidification)
• Acidic soil
• Some nutrients are dissolved
• Causes aluminum and other toxic metals to be
  released and absorbed by plants
• Aluminum causes root damage.

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Effects on Aquatic Ecosystems

• Change in waters pH can kill aquatic plants,
  fish, and animals.
• Acidic pH causes aluminum to leach out of soil
  and accumulate in fish gills so they cant
  exchange oxygen and salt. (Fish suffocate!)
• Acid shock sudden change in water pH due to
  excess runoff of acidic precipitation (mainly in
  Spring)

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Effects on Humans and Lifestyle

• Toxic metals released in acidic soils (aluminum,
  mercury, etc.) become part of food crops, water,
  and fish, then we ingest them.
• Possible connection between acid precipitation
  and respiratory problems in children
• Damage to fishing and forestry industries
• Can damage buildings and monuments

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Cleopatras Needle
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Challenges in Controlling Acid Precipitation

• Pollutants may be released in one geographical
  area and fall to the ground in another.
• SE Canadas acid precipitation is formed in Ohio,
  Indiana, Pennsylvania, Illinois, Missouri, West
  Virginia, and Tennessee!
• Acid precipitation falls downwind from where it
  is formed.

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International Conflict
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Know For TEST!

• Section Review (p.317) 1-3, 6