Acid rain has a pH around 4, whereas the pH of natural waters
containing living organisms is 6.5 to 8.5.
Natural
waters with a pH below 4 cannot sustain life.
–It
accumulates in rivers and lakes. The increased acidity of the water can affect
the growth and reproduction of aquatic organisms such as fish and pond
weed. The acidified water can react with the calcium carbonate in snails
shells, leading to weakened shells and less protection from damage.
–It
accumulates in the soil. The increased acidity of the soil can kill trees and
prevent seedlings from germinating.
Increased acidity of
lakes and rivers can be neutralized by adding limestone (see
Metals: Extraction for more).
It is too expensive to
remove sulfur from oil and coal prior to its use.
Therefore,
the SO2 is removed from fuel upon combustion.