Acid Precipitation

Sitting in your room late at night, you listen to the gentle pittter-patter of the rain on your window. Ahh, so soothing and relaxing. Have you ever really wondered what the rain is really made of? Is that just water or is it acid slowly streaming down out there? That rain you hear just might be acid rain, it could change the way you live your life.

The commonly used terms "acid rain" and "acid precipitation" describe specific forms of a type of pollution described generally as "acid deposition." Harmful gases that rise into the air mix with cloud moisture, sunlight, and oxidants. There they chemically combine into dilute sulfuric and nitric acids, which fall back to the earth. This is acid deposition. The major contributing pollutants are sulfur dioxide and nitrogen oxide (Morgan, 5).

"Acid rain" is basically rainwater with a pH level lower than 5.6 (Morgan, 3). The term pH means "potential hydrogen". When a substance has a pH level of 7, it is completely neutral with the same number of hydroxyl and hydrogen ions (Pringle, 6). Acidity in the atmosphere can be changed by many natural things. When a volcano erupts, sulfur dioxide is spewed out. Droughts produce unusually dry soil conditions allowing dust particles to be carried upward into the air, neutralizing the acids that may be present at the time (Pringle, 4). Acid Rain can come in concentrations sometimes more acidic than lemon juice. These pollutants reach the earth in rain, snow, hail, sleet, or fog. The rain at the beginning of a shower is usually more acidic than the rain that follows. Dry acidic particles can also fall from the atmosphere. Because wind can carry gases and moisture for hundreds of miles, even areas far away from the source bear the effects of acid deposition (Durham, 10). There are of course, many things that we as humans do everyday to promote and support the continuation of acid rain. Not intentionally, of course.

When the fossil fuel, (i.e. coal) is used, the sulfur in it mixes with Oxygen in the air to form sulfur dioxide. The sulfur dioxide is eventually turned into acid over a matter of days. Coal-fired power plants are the single greatest cause of acid rain in the United States. They account for two-thirds of all sulfur dioxide emissions in the US (Pringle 16; Morgan 75). In the mid-1980's, the United states alone discharged about 26 million tons of sulfur dioxide (Bennet). For decades, the highest source for sulfur dioxide emissions was the huge Inco, Limited, a copper and nickel smelter in Sudbury Ontario. Each year the Sudbury plant gave off 1% of the entire world's sulfur dioxide emissions, including both natural and human sources (Morgan, 24).

At a staggering 1,250 ft, "Superstack" is almost as tall as the Empire State Building. Its main purpose was to act as a giant chimney to take all toxins higher into the atmosphere so that we humans would not have to breathe them. The air quality around the smelter was much better and plant life started growing back. The problem was, the sulfur dioxide was then blown whichever the winds happened to be going. Most of the time those winds to the sulfur dioxide across state borders and into Canada (Morgan, 27) Scientists then used satellite photography to trace the weather patterns back to where the sulfur dioxide originated. The acid falling back down to earth, whether it is in dry or wet form has drastic consequences for many.

A rainstorm occurs in a forest. The summer rains wash the leaves of the branches and fall to the forest floor below. Some of the water is absorbed into the soil while other water run-off enters nearby streams, rivers, or lakes. When acid rain is absorbed into the ground, it slowly poisons the tree by being absorbed through the roots. Acidic rainwater also dissolves the nutrients and minerals that the plants need from the soil. When acid rain is frequent, leaves tend to lose their protective waxy coating. After a leaf loses it's protective, waxy coating, it becomes more susceptible to diseases. By damaging the leaves, the plant can not produce enough food energy for it to remain healthy. Trees no longer grow as fast as they did before. Leaves and pines needles turn brown and fall off when they are supposed to be green in color (Phamornsuwana).

Not only plants are effected by acid rain. Animals are as well. Animals in an aquatic biome suffer more extreme consequences than that of any other biome. The simplest way to show the amount of damage would be in the following record/chart. Diary of Death for aquatic life:

pH 6.5 The growth rate of brook trout slows and lake trout begin to have trouble reproducing. Clams and snails become scarce. Acid-tolerant organisms, such as certain rotifers and filamentous green algae, start to increase.

pH 6 Brook and rainbow trout populations start to decline. Smallmouth bass and spotted salamanders have trouble reproducing, as do several kinds of mayflies. Several species of clams and snails are wiped out.

pH 5.8 Tiny crustaceans called copepods die out, and some kinds of crayfish have trouble re-growing their hard exoskeletons after they molt.

pH 5.5 Rainbow trout and some smallmouth bass population are becoming extinct. Other trout, shiners, walleyes pike, and roach fail to reproduce and their numbers drop. Leeches and mayfly larvae disappear.

pH 5.4 The reproduction of most crayfish is impaired.

pH 5 All but one species of crayfish are dead. As are the brook trout, walleyed pike, and bullfrogs. Thick mats of green and blue-green algae cover the lake bottom. Some insects in crease because few fish are left to prey on them or because they live on the water surface. These include water boatmen and water striders.

pH 4.8 The number of leopard frogs declines, along with populations of rooted underwater pondweeds.

pH 4.5 Mayflies and stoneflies have all died out.

pH 4.3 Pumpkinseed sunfish population declines and northern pike have completely disappeared.

pH 4.2 The common toad dies out. It lives on land but must lay its eggs in ponds and lakes.

pH 4 The spring peeper, another amphibian the produces in ponds and marshes begins to die out. All aquatic plants except those that are acid tolerant are dead or in decline.

pH 3.5 Virtually all clams, snails, frogs, fish, and crayfish are missing from these acidic waters.