Friday, December 13, 2019
Acid Rain Free Essays
Acid rain is a rain or any other form of precipitation that is unusually acidic, i. e. elevated levels of hydrogen ions (low pH). We will write a custom essay sample on Acid Rain or any similar topic only for you Order Now It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxides which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcanic eruptions. The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn, who remarked upon the poor condition of the Arundel marbles. Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides to the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England. Though acidic rain was discovered in 1852, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. [6] The term ââ¬Å"acid rainâ⬠was coined in 1872 by Robert Angus Smith. 7] Canadian Harold Harvey was among the first to research a ââ¬Å"deadâ⬠lake. Public awareness of acid rain in the U. S increased in the 1970s after The New York Times promulgated reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects demonstrated to result from it. Occasional pH readings in rain and fog water of well below 2. 4 have been reported in industrialized areas. Industrial acid rain is a substantial problem in China and Russia and areas down-wind from them. These areas all burn sulfur-containing coal to generate heat and electricity. The problem of acid rain not only has increased with population and industrial growth, but has become more widespread. The use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation. [13][14] Often deposition occurs a considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition (simply because of their higher rainfall). An example of this effect is the low pH of rain (compared to the local emissions) which falls in Scandinavia. How to cite Acid Rain, Essay examples Acid rain Free Essays string(33) " highly toxic to many organisms\." The French chemist Ducros first used the term ââ¬Ëpluie acideââ¬â¢ in 1845. The phraqse ââ¬Ëacid rainââ¬â¢ ,was brought in 1872 by Robert Angus Smith (Wellburn, 1994). Back in fifties, there were observations of lakes in Scandinavia losing their fish populations. We will write a custom essay sample on Acid rain or any similar topic only for you Order Now Anglers and naturalists noticed that fish stocks in many lakes of southern Scandinavia were diminishing. Freshwater acidification had rapidly worsened over a few decades. Although acid rain and the acidification are a not new problem that has received considerable attention for many years, it was not until 1960s that scientists were able to link these effects to any specific cause. Later it was found to be atmospheric pollution. Acidification is not a regional phenomenon. In Scotland, studies show that the acidification began around the middle of the last centuries and the process has accelerated in the last three decades. In southern Norway, It has reported that 87 lakes had a pH below 5.5 (Mason, 1996). Damaged forests were becoming widespread in West Germany. As these examples show, acidification is an international problem. Pollutants may be carried with winds over distances, from points hundreds or thousands of miles away. Some countries are net importers of pollution, and others are exporters. The effects of acidification are varies, not only pollution of lakes and forests as previously mentioned, but also effects on fauna and flora, soil, groundwater and direct or indirect harm on human health, and all things are influenced by water quality through hydrological pathway (Thunberg, 1993). The aim of this report is to discuss causes and effects of acidification that has been concerned until now, and present possible short-term and long-term soluti on to acid deposition effects on water quality 1. Acidification and its causes Airborne pollution can influence the environment both directly and indirectly. Primary pollutant is Sulphur dioxide and nitrogen oxides. When these are present in high concentrations, they can cause damage on environment and humanââ¬â¢s health. These direct effects are often peak in the vicinity of the emission sources. Industrial society discharges suphur dioxide and nitrogen that form sulphuric acid and nitric acid, which may be carried with the winds over long distances before descending in rain or snow. Indirect effects often occur as acidified soil and water far away from the sources of emission (Thunberg, 1993). There are gas-phase reactions, which produce acidity in the atomosphere. Sulphur dioxide and nitrogen oxides form suophuric and nitric acids on coming into contact with water. When these acids reach the ground in rain and snow, it is called ââ¬Ëwet depositionââ¬â¢. However, acid oxides may also be deposited directy as gases, or cles, which is called ââ¬Ëdry depositionââ¬â¢. The rates of dry deposition velocity may depend on the nature of the land surfaces. Rates of wet deposition depend on the precipitation rate, the washout ratio of dissolved pollutant per unit mass of cloud water or rain divided by the concentration of the same pollutant per unit mass of air (Wellburn, 1994. A low pH value means a high level of acidification. Water in neutral condition has a pH of 7 (Thunberg, 1993). Sulphur and Nitrogen Cycles are presented below (Figure 1 and 2). Figure 1. Sulphur Cycle Source: ICU (2003) Figure 2. Nitrogen Cycle Source: ICU (2003) 1.1 Sulphur Sulphur compounds are responsible for about two-thirds of the acidification of rain. Sulphur in gaseous form, sulphur dioxide (SO2), is mainly formed in the combustion of oil and coal. The rapid increase in emission of pollutants came after the war followed by consumption of fuel and oil. It was reported that approximately 20 million tons of sulphur are now emitted every year in Europe. There is also a great deal of airborne pollution in North America, where about 12 million tons of sulphur is released every year. Sulphur can be formed by naturally by eruption of vulcanoes, from seas and oceans and certain processes in the soil. However, 90 per cent of the emissions of sulphur to the atmosphere are derived from industrialised parts of Europe and North America. This is ten times the level that can be considered natural (Thunberg, 1993). 1.2 Nitrogen Nitrogen oxides (NOX) are grouped term of nitrogen monoxide (NO) and nitrogen dioxide (NO2). Nitrogen oxides are formed in all types of combustion, most of the NOX are formed by the reaction of nitrogen gas in the combustion air with oxygen. When the mixture of nitrogen gas and oxygen is heated, they interrelate to form NOX. The higher the combustion temperature, the more NOX will be formed. The largest source of NOX emission is road traffic. These emissions are reported to have doubled during the 1960s, approximately 22 million tons of NO2 are released every year in Europe. Certain types of fertilizer are another source of nitrogen pollution. Nitrate leaching intensified the acidification of the soil, which release unwanted substances such as aluminium (Thunberg, 1993). 2. The environmental effects of acidification 2.1 water acidification and aquatic biota Acidification was first noticed in the lakes. The initial victims of acidification are nutrient-deficient lakes in areas where the soil has a poor buffering ability (Thunberg, 1993). It is reported that many lakes in the Rocky Mountain have little alkalinity to buffer increase in acid deposition, however loss of alkalinity has been observed caused by high concentration of acid deposition due to the emission in the Rocky Mountain region (Turk et al, 1989). Figure 3. Acidified lake: A deep blue colour of a lake is a sign of acidification. Source: ARIC (2000) In severely acidified lake, the fish will have vanished entirely, bog moss will have spread out over the lake floor, and only few plant and animal species will remain. The first victims of acidification are crayfish, snails and mussels, certain types of zoo- and phytoplankton, and some species of mayfly. Usually, certain types of bog moss and insects those are resistant to acidification remains. This is not only low pH value that takes a heavy toll of fauna and flora. In acid lakes there are increased concentrations of aluminium in ion form, which is highly toxic to many organisms. You read "Acid rain" in category "Papers" The loss of fauna / flora is due to the combination of a lowered pH and aluminium poisoning. The level of other heavy metals also rises such as cadmium, zinc, and lead. Those heavy metals including aluminium flow into lakes from the acidified soils of the surroundings. The relationship of prey and predators will also change, for instance certain insects on which they usually prey begin to thrive when their predators are disappeared (Thunberg, 1993). 2.2 Soil/water interactions Acidification process takes place naturally in the soil. The plant releases hydrogen ions as it uptake nutrients. Though the growth itself is acidifying, there is no net acidification where growth and decay are about equal. However, the cycle is broken by harvesting, the acidifying process will take over. Soil acidification may have biological effects in the respects through lowering of the pH value, an increase in the levels of aluminium and other toxic compounds and a loss of plant nutrients due to increased leaching, consequently may lower drainage water pH (Thunberg, 1993). Moreover, Long-term increase in nitrogen supply may be responsible for alterations in root and shoot growth of plants(Carrol et al, 2003). Figure 5. Soil pH range source ANRA (2003) 2.3 Effects of forestry practices Forestry practices can cause the soil and water to become acidified in several ways. Forest growth change drainage water pathways to stream, and increase stream water acidity. Extensive clear cutting can also accelerate the acidification of surface water. Applying acidifying fertilizer also helps to acidify soil and water (Thunberg, 1993). Twelve years studies of acidification-induced chemical changes in soils of Norway spruce and Scot pine in southern Sweden reveals that pH in mineral soil decreased on average 0.17 units between 1988 and 1999. It is said that these changes in forest soil are mainly due to the extensive deposition of acidifying substances (sulphur and nitrogen compounds) during the latter part of the 20th century (Jà ¯Ã ¿Ã ½nsson et al, 2003). In addition, atmospheric pollution directly damages forest itself. Since the early 1970s, West Germany has experienced a rapid and widespread decline in the health of its forest trees; especially sensitive species were affec ted by exposure to low levels of pollutants (Ling et al, 1987). 2.5 Groundwater quality Most of the precipitation sinks to some extent into the ground. The more permeable the soil, the more water dribbles down. Normally acid rain will become less acid as it penetrates through the ground. However, where the soil becomes acidified and has less ability to neutralize, the effect will be decrease until it finally ceases. It is unlikely that acid groundwater will be harmful to human health, however toxic heavy metals, such as aluminium and cadmium may appear at elevated level where highly acidic. These metals are harmful for human health (Thunberg, 1993). 3. Solutions Solutions to the problems of acidification fall into two groups, which are cure and prevention. Remedial measures can be applied where the problems actually arise (i.e. soils and surface waters). Preventive measures can be applied at source (i.e. at point of emission of the sulphur and nitrogen oxides). The latter are expensive and the least acceptable to industry, however they are in fact more effective, more sustainable, and more immediately required (Park, 1987). Causal treatment by reducing aciditying emissions is the primary goal in a long-term as preventive measures, however outcomes from this approach are still uncertain and recovery may be slow. Indicative treatment, involving the addition of neutralizing agent such as powdered limestone to affected environment is the only realistic remedy in the short-term, and has become a widespread practice in Europe (Thunberg, 1993). 3.1 Short-term solutions Remedial action should be taken after the problems happen. This requires not simply the elimination of symptoms of damage (i.e. restocking fish in acidified lakes, planting new trees); it also involves restoration of natural chemical balances to ensure that damage does not reappear. Some materials in nature have ability to buffer, or neutralize, or offset acid input. Lime and limestone are the most accepted of a range of chemicals that can be used to buffer acidic materials. Lime has been added normally by spraying from helicopter to catchments, soils and forests to alleviate damage and improve conditions for environment (Park, 1987). With regard to the lakes and streams, this raises pH value of the water and decrease in the levels of heavy metals. After the liming many species quickly return to their former habitat (Thunberg, 1993). This approach has been most widely investigated in Sweden (Park, 1987). This measure had been made in UK as well. Stream chemistry and biological effect was monitored for 10 years after the catchments of three acidified Welsh streams at Llyn Brianne were limed in 1987/88. This monitoring reveals that chemistry in treated streams changed significantly as mean annual pH increased from 5-5.1 before liming to 6.1-6.2; mean annual aluminium concentrations decreased from 0.15-0.18 to 0.05-0.11 mg L-1, and calcium concentrations increased from 0.8-2.0 to 2.4-4.5 mg L-1. The abundance of Acid-sensive taxa in limed streams increased after treatment. Liming has also been used as a means of restoring acidified soils. This improves the productivity of croplands and forests. However, liming can cause negative impacts on stream, such as fine CaCO3 deposited on the stream banthos. In addition, liming is an expensive ââ¬Ëcureââ¬â¢ measure. Sweden spent approximately $10 million from 1980-1983 for liming. Moreover, it is not practical for many lakes and rives, for some streams it is no help at all. There is uncertainty in relation to the effect of liming in a long run. Many studies have undertaken for the effects of post liming over short timescales, yet little has known about the long-term effects. At least 10 years monitoring is recommended (Bradley et al, 2002). Liming is a interim measures that provide biological defence, however it does not attack the root caused of the problems. It has been said that ââ¬Ëa sort of artificial respiration for dead lakes and streamsââ¬â¢. Therefore, real effective measures are long-term prevention deliberate through a sustained policy, rather than cure. 3.2 Long-term solutions The only way to solve the problem of acidification in the long run is to reduce emissions of pollutants. The central point of the political debate over acid rain is the need to reduce rainfall acidity by controlling emission of SO2 and NOX at source, mainly from power stations and vehicles: Reducing emissions of SO2 from power stations by: Burn less fossil fuel Switch to low-sulphur fuel Fuel desulphurisation Sulphur reduction at combustion Flue gas desulphurisation Disperse flue gases Reducing emission of NOx from power stations by: Reduce NOx emissions during burning Reduce NOx levels after burning Reducing emissions of NOx from vehicles by: Modify engines or exhausts to reduce emissions Change to different type of engine Transport planning It is said that technology of controlling and reducing such emissions already exist. Some methods should be applied separately or in combination to be able to bring reduction to agreed levels within agreed time-scales. However, this problem is not only to do with a technical one. Political goodwill is essential as this measures involves high cost. All the cost should be offset by positive side-effects such as the creation of new jobs and generation of useful by-products (i.e. commercial sulphuric acid), the values of conserving fish, forest and crops, and benefits in improved human health (Park, 1987). In recent decades, there have been national and international efforts to achieve reduction in emissions of sulphur and nitrogen compounds to the atmosphere (Ferrier et at, 2001). As previously mentioned, emissions of sulphur and Nitrogen are carried by air and deposited as gases and aerosols and dissolved in rainwater, in areas far from their sources. The quality of air is very much influenced by emissions in others, so it will benefit little for any country alone to reduce emissions. This is called transboundary Import-Export Budgets. Data for 1998 is presented in Appendix A Without international cooperation, there can be no real solution (Thunberg, 1993). The details of these treaties and protocols are presented in Appendix C 4. Improvement Recent data shows that both emissions seem steadily declined particularly after these treaties and protocols noted above have adopted (See appendix B). However, compared to reduction of SO2 emission, NOX emission need to be reduced further, especially U.S, whose emission has not been much reduced. Conclusion Acidification has a long history as posing adverse impacts on various ecosystems and human health. The main sources of pollution are SO2 and NOX. These pollutants are naturally exist, however recent increases of these pollutants are caused by human-induced factors, such as power generation and transportation. Remedial measures have been taken to abate damaged environment by acid deposition. Preventive measures have been adopted for preventing further damages. In attempts to make steadily progress for both redemption and prevention for solution of acidification for water quality, use of combination of short-term and long-term solution will be recommended. How to cite Acid rain, Papers Acid Rain Free Essays Rain is very important for life. All living things need water to live, even people. Rain brings us the water we need. We will write a custom essay sample on Acid Rain or any similar topic only for you Order Now But in many places in the world even where you live, rain has become a menace. Because of pollution in the air, acid gases from factories, cars and homes, the rain is becoming dangerous for the life of every living creature. This rain is known as ââ¬Ëacid rainââ¬â¢. Acid gases are produced when fossil fuels like coal and oil are burned in power stations, factories and in our own homes. Most of these acid gases are blown into the sky, and when they mix with the clouds it can cause rain ââ¬â or snow, sleet, fog, mist or hail ââ¬â to become more acidic. The opposites of acid are alkalis; for example, toothpaste and baking powder are both alkalis. Strong alkalis can also be dangerous, such as ammonia and bleach. Lemon juice, vinegar and cola are all acidic. Rain is naturally acidic, but acid gases make it even more acidic, sometimes as acid as lemon! Nature can also produce acid gases, such as volcanoes. When they erupt, the smoke that comes out of the crater is also full of acid gases. Air pollution can be carried over long distances. When acid gases are released, they go high up in the sky, and then they are pushed by strong winds towards other countries. The acid rain in Sweden is caused by air pollution in Britain and other countries of Europe. The pollution produced in Britain ends up mostly in Scandinavia ââ¬â countries in northern Europe including Sweden, Norway and Denmark. In the USA, the winds blow the air pollution to certain areas in Canada. When rain is acidic, it affects what it falls on: trees, lakes, buildings and farmland. Sometimes rain is not very acidic and does not cause a lot of problems, but when it is acidic, it can be very harmful to the environment. Acid rain can have terrible effects on a forest. The acid takes away important minerals from the leaves and the soil. Minerals are like vitamins for trees and plants. Without them, trees and plants cannot grow properly. They lose their leaves and become very weak. They are no longer strong enough to fight against illnesses and frost. They become very ill and can even die. Some soils are alkaline, when acid rain falls on them the acid becomes neutral. Plants and trees living on these soils are not in any big dangerâ⬠¦ Acid rain has a terrible effect on water life. Even if the acid rain does not fall straight into the lake, for example, it may enter from rivers and streams. Some of the life in the lake such as fish and plants may end up dying, because they cannot survive in acidic lakes. Thousands of lakes in Scandinavia have no more life in them. They have received so much acid rain for so many years, because of the winds pushing the acid gases, which nothing can survive. You can recognise a lake dead from acid rain by its clean and crystal clear water. But they look clean because there is very little living in them anymore. Tiny plants and animals are mostly unable to surviveâ⬠¦ Particulates ââ¬â very small particles of debris found in some of the air pollution ââ¬â are one of the main causes of health problems. In towns and cities, these are released mainly by diesel engines from cars and trucks. When we breathe in air pollution, these very fine particulates can easily enter our body, where they can cause breathing problems, and over time even cause cancer. Water we drink from taps can be contaminated by acid rain, which can damage the brainâ⬠¦ Acid rain can also ruin buildings because the acid eats into metal and stone. It also damages stained glass and plastics. Some types of building materials are softer than others, and it is the softer ones which are most affected by acid rain. Sandstone and limestone are examples of stone which are fairly soft and are damaged easily. Granite is an example of a harder stone that can resist the effects of acid rain. In many places in the world, ancient and famous buildings and monuments are affected by acid rain. For example, the Statue of Liberty in New York, USA, has had to be restored because of acid rain damage. Buildings are naturally eroded by rain, wind, frost and the sun, but when acidic gases are present, it speeds up the erosion. How to cite Acid Rain, Essay examples Acid Rain Free Essays We all live on the planet that provides us everything; we do not go anywhere else for anything. We get all we need on Earth. It might sound odd but its true and we take it for granted. We will write a custom essay sample on Acid Rain or any similar topic only for you Order Now In certain cultures, the Earth is called Mother Earth. We have been around for millions of years and we have been using the resources of our planet for our survival, from the last hundred odd years, we have started exploiting the resources of our planet more actively to make our lives comfortable. We basically use energy resources, but isnââ¬â¢t that all we need to survive? Energy is the key to survival, as humans. We need food for energizing our bodies and we need shelter to save us from the wrath of nature. However, in the last century we have been using the natureââ¬â¢s resources basically for our development and energy needs. We use coal, water, oil, land, forests and the sea for our energy needs. We also use renewable resources like wind and solar energy. Moreover, in big dams across the world we recycle water, the three gorges dam being made in china is an example of humans winning over nature, with its 2-mile long wall that stops the river Yangtze, Chinese hope to get around 24000 Mwt of energy from 26 turbines. However, they have moved around a million people from over 600 sq km of area that is going to be submerged once the dam gets operational in 2009. Projects as big as the Three Gorges dam may have happened only now but for decades, we have been doing great things to show our strength against nature. All this show of strength has only made us exploit nature and we are not habilitating nature the way we are exploiting it. Climate change along with Acid rain is the reality of our developed world. Climate change occurs due to the excess heat that the industrialized world produces while acid rain occurs due to sulfur and nitrogen based residuals that are produced from industrial processes. When sulfur dioxide and nitrogen oxides are emitted into the atmosphere, they mix with the moisture to form clouds and when it rains, the sulfur and the nitrogen come down as rain. The reason for acid rain is the increased pollution but primarily the use of coal. Across the world, we use coal widely to produce electricity. The residuals are then emitted into the atmosphere through long and high chimneys that save the low-lying air over the city to carry that pollution. However, the same residual is in the layers above and is blown away to different areas. That is why acid rain usually does not affect the areas where it is produced; at times, it affects areas that are hundreds of kilometers away from the site of the pollution. How to cite Acid Rain, Papers
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.