.. . These particles collect on the leaves of the tree, and studies have shown that when these particles contain acid they can cause damage to the leaves. The leaves are the part of the tree that help make food, hence any damage to the leaves will result in harm to the health of the entire tree. Coniferous trees are vulnerable to the harmful effects of acid rain as well.
The tree’s needles are designed to nourish the tree after they fall to the ground. Each needle houses whole colonies of microscopic bacteria and algae that help the tree change nitrogen into food at the roots. Acid rain will often burn away this material, thereby reducing adequate food supply, and weakening the tree’s health. After the damage has been done to leaves and needles, acid rain harms the trees even more through the soil. Soil has a level of acid.
Acid in the soil can do damage to the trees by releasing aluminum, which, once in contact with acid, becomes highly poisonous to forests. The aluminum will enter the tree’s hairlike roots, choking them, and when these become clogged, the upper branches are no longer nourished. Even though there may be plenty of moisture in the soil, the tree can die of thirst. Scientists have discovered that the aluminum content in soil has tripled since the 1960s.3 Acid rain also kills important organisms on the forest floor. The process of decomposition is interrupted as the acid kills many of the bacteria and fungi that live on the forest floor. At a pH level of 4.0, the earthworm dies, further damaging the decomposition process.
Without earthworms and bacteria to decompose the debris consisting of animal and bird droppings, twigs and dead leaves, the materials continue to build on the forest floor. When debris builds up, seedlings from the trees are not able to survive, because they can not work their way down to the soil to root. This causes the forest to slowly disappear, as older trees die, and the forest will not be able to rejuvenate itself. Acid rain is hardest on trees high up in mountains, because it is often covered in mist or fog, literally bathing the trees in an acidic atmosphere. Trees also suffer because of changes in the soil.
Acid rains leach metals (draw metals out of mud and rocks) in the soil, and the trees in turn intake these harmful metals through their roots. Figure 1-2 shows the damage that acid rain can to do a forest Human Health It is known that the earth contains many metals that are potentially dangerous to humans, such as lead, mercury, and aluminum. Most of the time these metals are harmless because they are in the soil, bonded to other elements. The problem occurs when acid detaches these metals from the rocks and soils, and can be carried deep into the ground and make their way to underground streams. These streams eventually connect to our water sources. Medical researchers have found these metals can be dangerous, and on rare occasion, is even fatal.
Aluminum has been found to kill people who have kidney problems, and can also collect in brain tissue. Some scientists even suspect that aluminum deposits on the brain cause Alzheimer’s disease. (A disease that results in memory loss, nervous system problems, and death. Acid rain is known to irritate the whole respiratory system, beginning with mucous membranes in the nose and throat, all the way to tissue in the lungs. Consequently, acid rain has an increased effect on people with respiratory problems. The U.S.
Council on Environmental Quality estimates health-related problems due to acid precipitation cost the United States $2 billion per year.4 In August 1987, over one hundred people were treated for eye, throat, and mouth irritation when 1.8 metric tonnes of highly toxic sulfur dioxide gas leaked from an Inco plant near Sudbury, Ontario. Even Fig 1-2 This picture shows how a coniferous forest has been virtually destroyed. Acid rain is blamed for the destruction of terrestrial ecosystems around the world. without accidents, the sulfur dioxide regularly emitted from Inco smokestacks has been linked to chronic bronchitis in Inco employees.5 Drinking Water Acid rain damages drinking water in various ways. Thus far, amounts of metals in drinking water have been minimal, however the fact that metals even leak into the water is troubling to scientists.
Since metals remain in the body once ingested, over time, small amounts accumulate into large quantities, and it has yet to be concluded how large an amount will prove to be harmful to humans. Acid rain causes damage by loosening metals off metal water pipes. Modern plumbing uses plastic tubing, but older systems have copper pipes. The copper pipes are held together by a mixture of tin and lead. Lead is known to be extremely dangerous to humans, even in small amounts, and will cause damage to the brain and nervous system.
A study that was done in Ontario found that water sitting in plumbing pipes for ten days contained hazardous levels of copper and lead. This discovery could be a widespread danger, since often people will go on vacation and not shut off the plumbing, allowing water to sit and absorb these dangerous metals. Acid rain can also dissolve the reinforcements that occur around large water pipes. In some parts of the United States, asbestos is used to reinforce the cement bases that hold water pipes. Asbestos is not dangerous when bound to the cement, but is highly dangerous when separated, and has been linked to cancer and other serious diseases.
Many health officials worry that loose asbestos will find it’s way to the city’s water when acid rain comes in contact with the cement. Effects On Man Made Structures Scientists are becoming increasingly concerned with acid rain’s destruction of the ‘built environment’. There are objects in our built environment that are irreplaceable. Historic landmarks and statues, old cathedrals and temples, paintings and sculpture – all are part of the built environment and are slowly being damaged. Some of these objects are practical, making life easier, safer or more comfortable. Many factors determine how much damage acid rain will do, including the amount of rain, the location, and direction of wind.
All influence the amount of corrosion done. Areas that have a large amount fog or humidity tend to suffer more than dry areas, which is why many steel bridges located over water get rusted and corroded by acid. When metal is decayed, it cannot take the same amount of stress of weight as when it was originally created. Acid rain has been blamed in several collapses of bridges around the world. Acid rain corrodes the steel track used on railroads, thus the tracks must be constantly checked.
Metal in air planes can also be eaten away by acid rain. The United States Air Force spends more that $1 billion every year to repair or replace damaged parts.6 A study done in Sweden showed that metal rusts four times faster in areas that receive a lot of acid rain. This figure is staggering, and yet, metal is not the only material damaged by acid rain. Houses and buildings made of brick and stone are affected as well. Acid rain can dissolve the mortar, which is used in cement to hold bricks together. When the mortar is worn away, the bricks crumble more easily, because they shift and cannot stay intact against the heavy weight of the bricks pressuring from above.
The corrosive effects of acid rain are particularly obvious on limestone, because it is composed of calcium carbonate, which is highly reactive with acid rain. Tombstones made of marble (which is metamorphosed or heated limestone) have been badly damaged, while older tombstones made of slate remain intact. Famous buildings such as the Taj Mahal, The United States Capitol building and the Lincoln Memorial in Washington, are all being continually damaged by acid rain. Statues made of bronze and copper are particularly susceptible to corrosion. These statues turn green naturally, and this covering, called a patina, acts as a protective shield against the elements.
Acid rain eats away at the patina, and where the acid dissolves the green covering, it leaves a streaky black coat. This process ruins statues throughout the world. How Does Acid Rain Affect the Economy? Canada/American Relations Canada is particularly susceptible to the effects of acid rain. Its geographical location places it directly in the path of a large amount of U.S. emission, and the granite bedrock of the Canadian Shield has a poor buffering quality.
(A buffer is a material that can chemically weaken acid soil and is less harmful to the environment, such as lime or baking soda.) The lack of such a quality renders Eastern Canada highly vulnerable to damage due to United States pollution. Canada suffers more from acid rain than the United States does, even though much of the pollution originates in the United States. Acid rain costs Canadians hundreds of millions of dollars every year. To try and decrease the large amounts of money the pollution is costing tax payers, Canada has passed laws to force its electrical companies to cut down on harmful emissions. However, no matter what laws are passed in Canada, it is not possible to stop U.S. power plants from sending acid in its direction.
Figure 1-3 displays amounts of emissions created by the United States and Canada. The Gavin power plant is an excellent example of how the United States sends tonnes of acid to Canada every year. Every hour, this power plant burns 600 tonnes of coal. The higher the smokestack, the further the dangerous gases will travel, and the Gavin smokestack is 1 103 feet tall.7 Obviously, The Gavin can not be solely blamed for the pollution, but it is power plants such as these that have caused trouble between the two countries. It is estimated that about 50% of the sulfate deposited in Canada derived from American sources.8 Sixty of the largest plants and thus largest polluters are located in the Ohio Valley, a short distance away from vulnerable Canadian land. In 1980, Canada and the United States signed a Memorandum of Intent, an agreement that both countries would make acid rain control a priority.
They both promised to focus on developing ideas to cut down the amount of sulfur dioxide and nitrogen oxide emissions being pumped into the air. In the past, Canada has presented devastatingly large figures to the United States, in an attempt to have them change laws and regulations regarding pollution. Unfortunately, the attempts thus far have been unsuccessful, as the US government requests more testing and studies instead of altering laws. In the recent past, the negotiations between Canada and United States representatives have been hardly reminiscent of efforts put forth by Canadian officials. Many U.S. politicians still qualify acid rain as a ‘minor’ problem, and it is treated as such, according to Raymond Robinson, chairman of the Canadian Environmental Assembly.