Acid Deposition

Acid Deposition Air pollution is one of several interacting stresses that can damage, weaken, or kill trees and pollute surface and groundwater. Acid deposition consists of rain, snow, dust, or gas with a pH lower than 5.6. As of 2010, the most acidic rain falling in the US has a pH of about 4.3

Emissions SO 2 NO x Acid deposition H2O2H2O2 O3O3 Others Direct damage to leaves & bark Reduced photo- synthesis and growth Susceptibility to drought, extreme cold, insects, mosses, & disease organisms Soil acidification Tree death Leaching of soil nutrients Release of toxic metal ions Root damage Reduced nutrient & water uptake Acids Lake Groundwater PANs

Acid Deposition Sulfur dioxides, nitrogen oxides, and particulates can react in the atmosphere to produce acidic chemicals that can travel long distances before returning to the earth’s surface. Tall smokestacks reduce local air pollution but can increase regional air pollution.

Acid Deposition Two main contributors to acid deposition Sulfur Dioxide (SO 2 ) Nitrogen Oxides (NO x ) * 66% of all sulfur dioxides and 25% of all nitrogen oxides comes from electric power generation that produces energy by burning fossil fuels.

Acid Deposition Acidic water flows over and through the ground which affects a variety of plants and animals Dry deposition refers to acidic gases and particles. About half of the acidity in the atmosphere falls back to earth through dry deposition. The wind blows these acidic particles and gases onto/into buildings, cars, homes, and trees

Acid Deposition Acidic water dissolves the nutrients and helpful minerals in the soil It washes nutrients away before plants can use them to grow Acid rain also causes the release of substances, such as aluminum, that are toxic to plants

Acid Deposition Acid rain does not usually kill trees directly Weakens trees Damages leaves Limits nutrients available Toxic substances are slowly released from the soil. Germany Mongolia South Carolina

Acid Deposition Acid Deposition can release aluminum from lake sediments which, in turn, adversely affects the gills of fish. Generally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch. At lower pH levels, some adult fish die. Chronic stress leads to lower body weight and smaller size Some acid lakes have no fish.

Acid Deposition During the 1970’s and 1980’s, many lakes in Canada and the Northeastern U.S. lost all of their fish due to lowered pH levels

Acid Deposition

pH measurements in relation to major coal-burning and industrial plants.

Acid Deposition

Antiquities can be destroyed by acid deposition

Acid Deposition Lime (calcium carbonate) can be deposited into a lake to increase the pH

Hubbard Brook Experimental Forest

ACID DEPOSITION Acid deposition contributes to chronic respiratory disease and can leach toxic metals (such as lead and mercury) from soils and rocks into acidic lakes used as sources for drinking water.

Solutions Acid Deposition PreventionCleanup Reduce air pollution by improving energy efficiency Add lime to neutralize acidified lakes Reduce coal use Add phosphate fertilizer to neutralize acidified lakes Increase natural gas use Increase use of renewable energy resources Burn low-sulfur coal Remove SO 2 particulates & NO x from smokestack gases Remove NO x from motor vehicular exhaust Tax emissions of SO 2