My first question is , What is Acid Rain? You hear about it all the time in the news and it is very important to the earths ecosystem. In simple terms, acid rain is rain that is more acidic than normal. All objects in nature have a certain level of acicicity but acid rain has too much acid in it. Acid rain is a complicated problem, caused by air pollution. Acid rain’s spread and damage involves weather, chemistry, soil, and the life cycles of plants and animals on the land and from acid rain in the water.
Acidity is measured using a pH scale, with the number 7 being neutral. Therefore, a body with a pH value of less than 7 is acidic. On the other hand, a value greater than 7 is basic. The pH of 5.6 has been used as the baseline in identifying acid rain, although this value is controversial, therefore, acid ran is any rainfall that has an acidity level above what is expected in non-polluted rainfall. Any precipitation that has a pH value of less than 5.6 is considered to be acid precipitation.
Readings of pH 2.4–as acidic as vinegar–were recorded during storms in New England. During one particularly acid summer storm, rain falling on a lime-green automobile leached away the yellow in the green paint, leaving blue raindrop shaped spots on the car.
Scientists have found that pollution in the air from the burning of fossil fuels is the main cause of acid rain. The major chemicals in air that help to create acid rain are sulfur dioxide, known as (SO2), and nitrogen oxides, known as (NOx). Acid rain is formed high in the clouds where sulfur dioxide and nitrogen oxides react with water, oxygen, and oxidants. This lethal mixture creates a mild solution of sulfuric acid and nitric acid. Sunlight often increases the speed at which the reaction occur. Rainwater, snow, fog, and other forms of precipitation containing these new solutions of sulfuric and nitric acids fall to earth as acid rain.
Acid rain does not make up all of the acidity that falls back to earth from pollutants. Only half of the acidity in the air falls back to earth through dry deposition as gases and dry particles. The wind blows and then these acidic grains are blown onto buildings, cars, homes, and trees. In some cases, these particles can eat away the objects which they land on. Dry deposited gases are sometimes washed from trees and other surfaces by rainstorms. When this occurs, the runoff water adds the new acids to the acid rain, making a more acidic combination than the falling rain by itself.
One of the main causes of acid rain is the sulfur dioxide. Sulfur dioxide is one of the main ingredients which make up the deadly combination that forms acid rain. Some of the natural sources that emit this gas are rotting vegetation, volcanoes, plankton, rotting animals and sea spray. However, the burning of fossil fuels, such as coal and oil, do not help the situation and are largely to blame for approximately half of the emissions of this gas in the world.
Water moves through living plants, animal, streams, lakes, and oceans in the hydrologic cycle. In that cycle, water evaporates from the land and sea into the atmosphere. Water in the atmosphere then condenses to form clouds. Clouds release the water back to the earth as rain, snow, or fog. When water droplets form and fall to the earth, they pick up particles and chemicals that float in the air. Even clean, unpolluted air has some particles such as dust or pollen. Clean air also contains naturally occurring gases such as carbon dioxide. The interaction between the water droplets and the carbon dioxide in the atmosphere gives rain a pH of 5.6, making even clean rain slightly acidic. Other natural sources of acids and bases in the atmosphere may lower or raise the pH of unpolluted rain. However, when rain contains pollutants, especially sulfur dioxide and nitrogen oxides, the rain water can become very acidic.
This problem is a problem of natures balance being tampered with. If not polluted, normal precipitation would react with chemicals that are derived from bedrock in the air, soil, lakes, and streams and this rain would be neutralized. Since the precipitation is highly acidic, these natural buffering chemicals will be destroyed. When this occurs, the natural buffering effect does not occur, and nature wont keep its balance
Acid rain has been a big problem for a long time. Research on acid rain is just starting to make progress. In the past, little was known about the causes and effects of acid rain.
Lakes, rivers, oceans, and other aquatic ecosystems are largely affected by acid rain. The reason why acid rain has such a large affect on aquatic ecosystems is because there as so many routes in which acidic chemicals can enter the water. Chemical substances enter the water in different ways. Some of the ways acidic chemicals enter waterways are as dry particles. These chemicals can also get into the water in forms such as rain, hail, dew, fog and snow. Another way that acids enter the lakes is called spring acid shock. An example of spring acid shock is when snow melts in the spring rapidly as a result of a sudden temperature change.
The acids in the snow are then put into the soil. The melted snow in return runs off to smaller water sources, and gradually make their way into the larger water ecosystems. This causes a sudden drastic change in the pH level. The aquatic ecosystem doesnt have time to adjust to the drastic change. This is also very dangerous because in the springtime many aquatic species are reproducing. Some of these species lay their eggs in the water to hatch. The sudden pH change can cause serious deformities in their young or even kill off the whole species since the young spend a lot of their crucial primary life cycle in the water.
Sulfuric acid in water can affect the fish in the water in two ways: directly and indirectly. Sulfuric acid directly interferes with the fish’s ability to take in salt, oxygen and nutrients crucial for daily life. Osmoregulation is the process of maintaining the delicate balance of salts and minerals in their tissues. For freshwater fish, maintaining osmoregulation is key in their survival. Acid molecules, which are a result of acid rain in the water, cause mucus to form in the fishs gills. This in return prevents the fish from absorbing oxygen. If the fish are unable to absorb oxygen, the consequence could be the eventual suffocation of fish and the low pH could throw off the balance of salts in the fish tissue.
Salt levels such, as the calcium (Ca+2), levels of some fish cannot be maintained due to pH change. This can results in poor reproduction. The fishs eggs produced would be damaged, they could either be too brittle or too weak. The decreased Ca+2 levels also result in weak spines and deformities. Acid Rain is very tragic when it come to the life of fish, but when nitrogen-containing fertilizers are washed off into the lakes, the nitrogen stimulates the growth of algae, which logically would mean an increase in oxygen production, thus benefiting the fish. This can be beneficial, but because of increased deaths in the fish population due to acid rain, the decomposition process uses up a lot of the oxygen, which leaves less for the surviving fish to take in.
Indirectly, sulfuric acid releases heavy metals present in soils to be dissociated and released. For example, aluminum (Al+2) is harmless as part of a compound, but because acid rain causes Al+2 to be released into the soils and gradually into the lakes, it becomes lethal to the health of the fish in the lakes on its life forms.
Some of the pH level effects are ; At pH level six basic forms of food die off for fish. The food sources cannot survive at this pH level. At a pH level of 5.5 there are more deformed adult fish due to lack of nutrients. The fish cannot reproduce. The young have difficulty staying alive, and eventually the older fish will die of suffocation. At pH level 5.0 the whole fish population will die off. At pH level 4.0 all life forms will die.
Fish, being one of the most important members of the food chain, provide nourishment for other creators. Since acid rain is affecting fish, this makes it dangerous for other creators including humans to eat the fish. Other sea dwellers such as amphibians are also affected by acid ran. The amphibian embryos have membranes that are too tough because of the acids, such that they are unable to break through at the proper time. So, they continue to grow, only to have deformed spines.
The affects on water forms are the greatest and most tragic of all of the things that acid rain affects. Acid rain affects all that eat seafood or any other water dwelling life form.
Another things impacted by acid rain are forests and soil. When acid rain falls onto the earth’s surface it causes a lot of damage. The soil is robbed of some vital things. Aluminum that is always present in the soil is freed, and the toxic element is absorbed by the roots of trees. The trees in turn are starved and deprived of vital nutrients such as calcium and magnesium. Sulfuric acid returns to earth. When the sulfuric acid returns, it clogs up the stomata in the leaves, stopping photosynthesis. In addition, severe frosts may also further aggravate this situation. With sulfur dioxide, ammonia and ozone present in the air, the frost-hardiness of trees are reduced. Ammonia mixes with sulfur dioxide and forms ammonium sulfate. This product forms on the surface of the trees. When ammonium sulfate reaches the soils, it reacts to form both sulfuric and nitric acid. Such conditions also stimulate the growth of fungi and pests like the ambrosia beetle. When trees are under such stress, they release chemicals such as terpenes which attract the ambrosia beetle.
Acid rain also affects the atmosphere. The affects on the atmosphere are mostly due to dry deposition that was mentioned earlier. The floating particles can contribute to haze, which affects visibility. This makes navigation especially hard for air pilots. The acid haze also inhibits the flow of sunlight from the sun to the earth and back.
Acid rain also affects architecture. Architecture is affected by both dry precipitation and wet precipitation. When these particles land on building they eat into the concrete eventually destroying them. This is a potential danger because the infrastructure of the buildings can be destroyed, thus hurting people occupying the building
Acid Rain also has a direct affect on you and I. The SO2 and NO2 emissions give rise to respiratory problems such as asthma, dry coughs, headaches, eye, nose and throat irritations. The indirect affect of acid rain are on the food that we eat. Acid rain is absorbed in fruits, and in the tissues of animals. Although these toxic metals do not directly affect the animals, they have serious affects on humans when they are being consumed.
Acid rain is a huge problem which affects every person living in the world in some sort of way. Acid rain is a problem that can be reduced but not stopped completely due to the needs of our modern society. Some ways that we could help to reduce acid rain is by recycling, carpooling, and reducing. Acid rain is a problem that can be controlled but it is up to the people of earth to control the problem.
1. Heij, G.J. and J.W. Erisman (Editors). Acid Rain Research: Do we have enough answers? New York: Elsevier, 1995.
2.Comptons New Media Encyclopedia 1996
3. White, James C. (Editor). Acid Rain: The Relationship between Sources and Receptors. New York: Elsevier, 1988.
4.FAQ on Acid Rain(http://ns.doe.ca/aeb/ssd/acid/acidFAQ.html)