3.1 Acid Deposition, Water Pollution, Fresh Drinking Water

What is Acid Deposition?• Acid deposition is any combination of airborne and

dry acidic particles and precipitation that falls to the earth

• It occurs in forms such as rain, snow, mist and fog

• Dry deposition polluting particles and gases stick to the ground via dust and smoke in the absence of precipitation

• Wet deposition is any form of precipitation that removes acids from the atmosphere and deposits them on the Earth's surface

Causes of Acid Deposition• Two main causes are natural emissions, and human

activity.

• Natural Causes: volcano emissions, lightning, and microorganisms.

• Human Causes: industrial emissions, and other man-made polluters.

Causes continued...

• Both humans and nature cause acid deposition, but man-made sources release twice as much as airborne acid.

• Two huge contributors are power plants and automobiles.

Effects of Acid Deposition

• Aquatic settings are the most clearly impacted by acid deposition because acidic precipitation falls directly into them. Both dry and wet deposition also runs off of forests, and roads, and flow into lakes, rivers, and streams

• In water, acid deposition mutates and kills fish. If the fish live, it is unsafe to eat because of all the acid

Effects continued...

• Acid rain also harms the soil that the trees are growing in by taking most of the valuable nutrients away from the soil.

• Acid rain, acid fog, and acid vapor also damage forests by damaging the surface of the leaves and needles.This makes it harder for the trees to withstand the cold and will cause the tree to die.

Technologies to reduce Acid Deposition•One device that can help reduce acid deposition is

scrubbers. Scrubbers are systems that are made to chemically remove SO2 from gases.

• If power plants were to switch to burning natural gas instead of coal, that would help reduce acid deposition as well.

• Vehicles now have a new design called catalytic converters, that help treat exhaust and remove pollutants.

Scrubber

• Water can dissolve nutrients such as nitrates and phosphates, allowing plant roots to absorb them

• Water can move against gravity, carrying nutrients up plant stems and trunks to cells throughout the plant

• Water dissolves carbon dioxide and oxygen bringing these gases to organisms in aquatic ecosystems

• Water also plays an important role in photosynthesis and cellular respiration

The Role of Water in Nutrient Cycling

Water Pollution

• Water pollution occurs when pollutants are discharged directly or indirectly into water bodies.

• It affects plants and organisms in these bodies of water. In most cases the effects is damaging not only to individual species and populations, but also the biological communities.

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