IB Environmental Systems and Societies/Acid deposition

Topic 5.8: Acid Deposition

Key Vocabulary:

-Acid Deposition: The accumulation of acids or acidic compounds on the surface of the Earth, in lakes or streams, or on objects or vegetation near the Earth’s surface, as a result of their separation from the atmosphere. -Dry Deposition: Emitted from industrial complexes, vehicles and urban areas. -Wet Deposition: Acids that dissolve in cloud droplets, (rain, snow, mist, and hail) that reach the ground. -Acid Rain: rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions, can have harmful effects on plants and infrastructure.

Assessment Statements:

-5.8.1: Outline the chemistry leading to the formation of acidified precipitations *refer to Figure 5.14 on the back* -5.8.2: Describe three possible effects of acid deposition on soil, water, and living organisms. * (1) increased levels of dissolved metals such as copper, aluminum, zinc, and lead. (2) breaks down lipids in the foliage and damages membranes which can lead to plant death. (3) an impoverished (poor) species structure. -5.8.3: Explain why the effect of acid deposition is regional rather than global. *Acid deposition is regional rather than globally because it is predominantly focused in a certain area. Such as in the 1980s and 1990s it affected Sweden, eastern North America, Germany, Belgium, and Norway amongst others. -5.8.4: Describe and evaluate pollution management strategies for acid deposition. *burn less fossil fuel (this requires a government initiative in order to switch to nuclear or Hydro-power) *allow decomposition of plants to return nutrients to the soil and offset the acidification process. *burn coal in presence of crushed limestone in order to reduce the acidification process *switch to low sulfur fuel (oil/gas plus high-grade coal)

Causes of Acidification:

-Human Activities - Acidification is largely related to human activity. Many countries produce the pollutants and they may be deposited many hundreds of kilometers from their point of origin. However, there are variations within areas receiving acid rain. Some storms produce more acid rain than usual; lime-rich soils and rocks are better able to absorb and neutralize the acidity. -Natural Sources/Causes - Bog moss secretes acid, heathers increase soil acidity and conifer plantations acidify soils. Litter from conifers is acidic and not easily broken down – the Sitka spruce is non-native to Britain and specialized decomposing bacteria are absent. This leads to the accumulation of an acid humus layer in the soil. -Volcanoes are also important sources of sulfur dioxide and nitrogen dioxide. For example, before the eruption of the Soufriere volcano in 1995, Montserrat had some of the finest cloud forest in the Caribbean.