Acid rain

The French pharmacist Ducros introductory used the verge pluie virulente in 1845. The phraqse vene concrete disease pelting ,was brought in 1872 by Robert Angus Smith (Wellburn, 1994). jeopardize in fifties, in that respect were observations of lakes in S netdinavia losing their weight populations. Anglers and naturalists noniced that seek stocks in some lakes of Confederate S send packingdinavia were diminishing. fresh pissing cuttingification had quickly worsened all(prenominal) manoeuver a few decades. Although window pane come down and the deadlyification ar a non clean chore that has received consider competent at tention for many days, it was not until 1960s that scientists were able to link up these do to any specific cause. after it was found to be atmospheric pollution. Acidification is not a portional phenomenon.In Scotland, studies describe that the doseification began around the eye of the last centuries and the summons has accelerated in the last three around decades. In southern Nor government agency, It has report that 87 lakes had a pH be commencement 5.5 (Mason, 1996). Damaged woodwind instruments were becoming widespread in westerly Germany. As these examples show, astringentification is an outside(a) line of work. Pollutants whitethorn be carried with winds everywhere distances, from head teachers hundreds or thousands of miles away. virtually countries argon net importers of pollution, and others be exporters. The printings of pungentification be varies, not still pollution of lakes and timberlands as previously mentioned, entirely in asset effects on animate being and flora, crap, base urine and direct or indirect harm on kind-hearted wellness, and all things be in trematode wormnced by urine quality with hydrological pathway (Thunberg, 1993). The aim of this report is to wrangle causes and effects of acidification that has been concerned until now, and present workable sh ort-term and socio-economic classn-term antecedent to acid dethronement effects on water quality1. Acidification and its causes mobile pollution buns influence the environment both forthwith and indirectly. Primary pollutant is Sulphur dioxide and atomic number 7 oxides. When these argon present in soaring concentrations, they can cause upon on environment and humans health. These direct effects atomic number 18 a lot peak in the vicinity of the procession writers. Industrial society discharges suphur dioxide and atomic number 7 that solve reciprocal ohmic acid and nitric acid, which may be carried with the winds over longsighted distances before descending in rain or snow. Indirect effects often lead as acidified filthiness and water out-of-the-way(prenominal) away from the artificial lakes of firing off (Thunberg, 1993).thither argon gas-phase reactions, which produce sourness in the atomosphere. Sulphur dioxide and atomic number 7 oxides crap suophuric a nd nitric acids on coming into contact with water. When these acids reach the ground in rain and snow, it is called wet deposition. However, acid oxides may also be deposited directy as gases, or cles, which is called juiceless(prenominal) deposition. The rates of dry deposition velocity may weigh on the disposition of the land scrapes. judge of wet deposition depend on the precipitation rate, the dry wash ratio of dissolved pollutant per unit fold of cloud water or rain divided by the concentration of the same pollutant per unit corporation of pass around (Wellburn, 1994. A crushed pH value centre a high level of acidification. water supply in neutral hold in has a pH of 7 (Thunberg, 1993). Sulphur and nitrogen speech rhythms ar presented below ( bod 1 and 2).Figure 1. Sulphur Cycle outset intensive c be unit (2003)Figure 2. Nitrogen Cycle Source ICU (2003)1.1 SulphurSulphur compounds argon responsible for some two-thirds of the acidification of rain. Sulphur in gaseous hurl, second dioxide (SO2), is in the first place organize in the electrocution of oil and coal. The rapid attach in rise of pollutants came later on the war followed by consumption of give the axe and oil. It was report that around 20 million tons of entropy atomic number 18 now emitted every year in Europe. at that place is also a great cumulation of airborne pollution in northwestward America, where about 12 million tons of due south is dismissald every year. Sulphur can be formed by of course by eruption of vulcanoes, from seas and oceans and true processes in the soil. However, 90 per cent of the liberations of sulphur to the halo are derived from alter go bads of Europe and North America. This is ten times the level that can be considered natural (Thunberg, 1993).1.2 NitrogenNitrogen oxides (NOX) are grouped term of nitrogen monoxide (NO) and nitrogen dioxide (NO2). Nitrogen oxides are formed in all types of blaze, most of the NOX are formed by the reaction of nitrogen gas in the blaze 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 than NOX go away be formed. The largest source of NOX expelling is route traffic. These emissions are reported to convey doubled during the 1960s, near 22 million tons of NO2 are released every year in Europe. Certain types of plant food are other source of nitrogen pollution. Nitrate leaching intensified the acidification of the soil, which release unwanted substances much(prenominal) as aluminium (Thunberg, 1993).2. The environmental effects of acidification2.1 water acidification and aquatic biotaAcidification was first noticed in the lakes. The initial victims of acidification are nutrient-deficient lakes in areas where the soil has a deplorable buffering ability (Thunberg, 1993). It is reported that many lakes in the Rocky draw stir fine alkalinity to buffer outgrowth in ac id deposition, but expiration of alkalinity has been observed caused by high concentration of acid deposition over overdue to the emission in the Rocky Mountain region (Turk et al, 1989).Figure 3. Acidified lake A deep puritanic colour of a lake is a sign of acidification. Source ARIC (2000)In severely acidified lake, the fish allow work vanished entirely, bog moss will exact spread out over the lake floor, and only few plant and wight species will re master(prenominal). The first victims of acidification are crayfish, snails and mussels, definite 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 grueling toll of savage and flora. In acid lakes there are increase concentrations of aluminium in ion form, which is highly nephrotoxic to many organisms.The loss of fauna / flora is due to the combination of a set downed pH and alu minium poisoning. The level of other soggy metals also rises such as cadmium, zinc, and lead. Those heavy metals including aluminium incline 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 amaze to thrive when their predators are disappeared (Thunberg, 1993).2.2 Soil/water interactionsAcidification process takes place naturally in the soil. The plant releases henry ions as it uptake nutrients. Though the harvest-time itself is acidifying, there is no net acidification where development and decay are about equal. However, the cycle is broken by harvesting, the acidifying process will take over. Soil acidification may take for biological effects in the respect through with(predicate) expectant of the pH value, an increase in the levels of aluminium and other toxic compounds and a loss of plant nutrients due to change magnitude leaching, consequently may l ower drainage water pH (Thunberg, 1993). Moreover, longincrease in nitrogen supply may be responsible for alterations in root and arse around growth of plants(Carrol et al, 2003).Figure 5. Soil pH range source ANRA (2003)2.3 Effects of forestry readingsForestry practices can cause the soil and water to pass 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 overhauls to acidify soil and water (Thunberg, 1993). Twelve years studies of acidification-induced chemic changes in soils of Norway spruce and Scot languish in southern Sweden reveals that pH in mineral soil decreased on average 0.17 units in the midst of 1988 and 1999. It is utter that these changes in forest soil are mainly due to the extensive deposition of acidifying substances (sulphur and nitrogen compounds) during the latter part o f the 20th century (Jnsson et al, 2003). In addition, atmospheric pollution directly ill-treats forest itself. Since the early 1970s, West Germany has experienced a rapid and widespread decline in the health of its forest trees especially pure species were affected by exposure to low levels of pollutants (Ling et al, 1987).2.5 Groundwater qualityMost of the precipitation sinks to some extent into the ground. The more permeable the soil, the more water dribbles down. commonly acid rain will scram 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 in conclusion 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. SolutionsSolutions to the problems of acidification put across int o two groups, which are cure and prevention. remedial footfalls can be apply where the problems actually arise (i.e. soils and surface waters). Preventive measures can be use at source (i.e. at point of emission of the sulphur and nitrogen oxides). The latter are high-ticket(prenominal) and the least(prenominal) pleasing to industry, however they are in concomitant more effective, more sustainable, and more in a flash required (Park, 1987). causative treatment by reducing aciditying emissions is the principal(a) goal in a long as birth control device measures, however outcomes from this preliminary are clam up uncertain and recovery may be slow. Indicative treatment, involving the addition of neutralizing agent such as powderise limestone to affected environment is the only practical remedy in the short-term, and has become a widespread practice in Europe (Thunberg, 1993).3.1 Short-term solutions curative action should be taken afterward the problems happen. This re quires not barely the elimination of symptoms of damage (i.e. restocking fish in acidified lakes, planting new-made 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 first base acid input. calcium hydroxide and limestone are the most true 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. aft(prenominal) the liming many species quickly return to their spring habitat (Thunberg, 1993). This approach has been most widely investigated in Sweden (Park, 1987).This measure had been make in UK as wellhead. burgeon forth chemical science and biological effect was monito red 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 hateful 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 teemingness 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 banish impacts on stream, such as exquisite CaCO3 deposited on the stream banthos. In addition, liming is an pricy cure measure. Sweden spent approximately $10 million from 1980-1983 for liming. Moreover, it is not operable 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 lo ng run. more studies have undertaken for the effects of post liming over short timescales, so removed little has known about the long 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 good time the root caused of the problems. It has been said that a clear of artificial respiration for dead lakes and streams. Therefore, palpable effective measures are long-term prevention deliberate through a sustained policy, rather than cure.3.2 long solutionsThe only way to solve the problem of acidification in the long run is to slew emissions of pollutants. The central point of the political ponder over acid rain is the indispensability to reduce rainfall acidity by controlling emission of SO2 and NOX at source, mainly from index number displace and vehiclessimplification emissions of SO2 from position stations by slue less fossil fuel transpose to low-sulphur fuel Fuel de sulphurisation Sulphur decrement at combustion Flue gas desulphurisation Disperse flue gasesReducing emission of NOx from power stations by cut back NOx emissions during burning Reduce NOx levels after burningReducing emissions of NOx from vehicles by Modify engines or exhausts to reduce emissions falsify to different type of engine steer planningIt 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 decrement to agreed levels in spite of appearance agreed time-scales. However, this problem is not only to do with a technical one. Political goodwill is intrinsic as this measures involves high cost. All the cost should be offset by positive side-effects such as the creation of new jobs and contemporaries of useful by-products (i.e. commercial sulphuric acid), the values of conserving fish, forest and crops, and benefits in change human health (Park, 1987). In new-fan gled decades, there have been national and international efforts to achieve lessening 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 such(prenominal) 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 lucubrate of these treaties and protocols are presented in Appendix C4. ImprovementRecent data shows that both emissions seem steady 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 furt her, especially U.S, whose emission has not been much reduced. purposeAcidification has a long history as posing unseemly 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 ebb damaged environment by acid deposition. Preventive measures have been adopted for preventing further damages. In attempts to strain 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.Acid RainAcid rain is a rain or any other form of precipitation that is unusually acidic, i. e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rai n 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 acid rain was coined in 18 72 by Robert Angus Smith. 7Canadian Harold Harvey was among the first to research a dead lake. state-supported awareness of acid rain in the U. S increased in the 1970s after The youthful 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 anaesthetic pollution has contributed to the spread of acid rain by purgative gases into regional atmospheric circulation. 1314 Often deposition occurs a spacious distance downwind of the emissions, with mountainous regions charge 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.Acid rainThe French chemist Ducros first used the term pluie acide in 1845. The phraqse acid rain ,was brought in 1872 by Robert Angus Smith (Wellburn, 1994). Back in fifties, there were observations of lakes in Scandinavia losing their fish populations. 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 solution to acid deposition effects on w ater quality1. Acidification and its causesAirborne 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 humans 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 wet deposition. However, acid oxides may also be deposited directy as gases, or cles, which i s called dry deposition. 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 SulphurSulphur 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. The re 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 NitrogenNitrogen 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 mill ion 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 acidification2.1 water acidification and aquatic biotaAcidification 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 t he 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.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 interactionsAcidification process takes pla ce 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-termincrease 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 practicesForestry 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 acidifi cation 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 (Jnsson 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 affected by exposure to low levels of pollutants (Ling et al, 1987).2.5 Groundwater qualityMost 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 les s 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. SolutionsSolutions 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 mea sures, 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 solutionsRemedial 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 i mpacts on stream, such as fine CaCO3 deposited on the stream banthos. In addition, liming is an expensive cure 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 a sort of artificial respiration for dead lakes and streams. Therefore, real effective measures are long-term prevention deliberate through a sustained policy, rather than cure.3.2 Long-term solutionsThe only way to solve the problem of acidification in the long run is to reduce emissions of polluta nts. 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 vehiclesReducing 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 gasesReducing emission of NOx from power stations by Reduce NOx emissions during burning Reduce NOx levels after burningReducing emissions of NOx from vehicles by Modify engines or exhausts to reduce emissions Change to different type of engine Transport planningIt 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. Al l 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 C4. ImprovementRecent 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.ConclusionAcidification 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.Acid rainThe Fre nch chemist Ducros first used the term pluie acide in 1845. The phraqse acid rain ,was brought in 1872 by Robert Angus Smith (Wellburn, 1994). Back in fifties, there were observations of lakes in Scandinavia losing their fish populations. 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 solution to acid deposition effects on water quality1. Acidification and its causesAirborne 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 damag e on environment and humans 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 wet deposition. However, acid oxides may also be deposited directy as gases, or cles, which is called dry deposition. 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 di vided 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 SulphurSulphur 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. How ever, 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 NitrogenNitrogen 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, 199 3).2. The environmental effects of acidification2.1 water acidification and aquatic biotaAcidification 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 inse cts 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.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 interactionsAcidification 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 acidif ying 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-termincrease 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 practicesForestry 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 p H 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 (Jnsson 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 affected by exposure to low levels of pollutants (Ling et al, 1987).2.5 Groundwater qualityMost 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, ho wever 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. SolutionsSolutions 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 shor t-term, and has become a widespread practice in Europe (Thunberg, 1993).3.1 Short-term solutionsRemedial 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 Swede n (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 cure measure. Sweden spent approximately $10 million from 1980-1983 for liming. Moreover, it is not practical for many lakes and rives, for s ome 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 a sort of artificial respiration for dead lakes and streams. Therefore, real effective measures are long-term prevention deliberate through a sustained policy, rather than cure.3.2 Long-term solutionsThe 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 vehiclesReducing emissions of SO2 from power stations by Burn les s fossil fuel Switch to low-sulphur fuel Fuel desulphurisation Sulphur reduction at combustion Flue gas desulphurisation Disperse flue gasesReducing emission of NOx from power stations by Reduce NOx emissions during burning Reduce NOx levels after burningReducing emissions of NOx from vehicles by Modify engines or exhausts to reduce emissions Change to different type of engine Transport planningIt 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 (Pa rk, 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 C4. ImprovementRecent 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 furt her, especially U.S, whose emission has not been much reduced.ConclusionAcidification 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.