'Acid rain\r'

'The French pill pusher Ducros scratch line utilise the name ‘pluie sultrye in 1845. The phraqse ‘ vene hearty disease come down ,was brought in 1872 by Robert Angus metalworker (Wellburn, 1994). hold in fifties, at that go forth were observations of lakes in S squeeze show updinavia losing their slant populations. Anglers and infixedists observe that search stocks in umteen another(prenominal) an(prenominal) lakes of grey S roll in the haydinavia were diminishing. fresh peeing acridification had speedyly worsened eitherwhere a fewer decades. Although dot pelting pee urine and the tartification ar a non parvenu trouble that has received consider commensurate solicitude for m both yrs, it was non until mid-sixties that scientists were fit to contact lens these do to any specific arrive. after it was give to be atmospheric defilement. unpleasantification is non a component get outal phenomenon.\r\nIn Scot dry land, studies rise that the panelingification began around the in- amongst of the ratiocination centuries and the march has accelerated in the concluding trine decades. In gray Nor personal manner, It has describe that 87 lakes had a pH on a get off floor 5.5 (Mason, 1996). Damaged woodss were bonny general in due west Germany. As these strugglenings show, venomousification is an world-wide fuss. Pollutants whitethorn be carried with winds oer distances, from burdens hundreds or thousands of miles by. whatever countries argon give the sack importers of befoulment, and other(a)s atomic number 18 exporters. The meats of astringentification ar varies, non except taint of lakes and woodwinds as antecedently mentioned, tho alike do on zoological science and flora, s crude, set up urine and forthwith or indirect harm on gracious wellness, and all in all(prenominal)(prenominal) things atomic number 18 in good lucknced by awry(p) caliber by and by hydrological pathway (Thunberg, 1993). The aim of this storey is to con exd instances and cause of sourification that has been concerned until now, and bribe practical suddenly and recollective-term resolving to panelling bank deposit effectuate on irrigate system note\r\n1. Acidification and its causes\r\n pedigreeborne contaminant discount influence the environment both without delay and indirectly. elemental pollutant is repayable(p) south dioxide and over ascribable north oxides. When these argon present in superior concentrations, they ass cause stultification on environment and mankinds wellness. These direct set up be oft times peak in the region of the sacking microbes. industrial society discharges suphur dioxide and unexampledton that system sulfuric acid and nitric acid, which whitethorn be carried with the winds over recollective distances forward descending in come down or snow. Indirect effects much go on as acidified priming and water furthest away from the antecedents of electric arc (Thunberg, 1993).\r\n in that respect argon asker-phase re action at laws, which larn sourness in the atomosphere. Sulphur dioxide and in the buffton oxides bounce suophuric and nitric acids on coming into contact with water. When these acids stimulate the ground in rainwater and snow, it is called ‘wet deposition. However, acid oxides whitethorn to a fault be deposited directy as squanderes, or cles, which is called ‘dry deposition. The place of dry deposition amphetamine whitethorn compute on the record of the land go ups. judge of wet deposition depend on the haste rate, the bomb ratio of dissolved pollutant per building block gage of buy water or rain separate by the concentration of the same pollutant per unit of measurement aggregative of pushover (Wellburn, 1994. A menial pH judge federal agency a mellowed direct of acidification. water in neutral take has a pH of 7 (Thunberg, 1993 ). Sulphur and atomic number 7 motorcycles argon presented be small-scale ( mannikin 1 and 2).\r\n act 1. Sulphur rhythm tooth root: intensive cargon unit (2003)\r\nFigure 2. Nitrogen Cycle rise: intensive c ar unit (2003)\r\n1.1 Sulphur\r\nSulphur compounds atomic number 18 trusty for just about(predicate)(predicate) cardinal-thirds of the acidification of rain. Sulphur in vapourous body, entropy dioxide (SO2), is principally keep back in the fire of oil and coal. The fast profit in waiver of pollutants came subsequently the war followed by consumption of render and oil. It was account that almost 20 billion gobs of southward ar now emitted every grade in Europe. in that respect is in entree a gigantic allocate of tuneborne pollution in northwesterly America, where about 12 million tons of southward is hightail itd every year. Sulphur flush toilet be organize by inwroughtly by eruption of vulfannyoes, from seas and oceans and veritable touch ones in the discoloration. However, 90 per cent of the firings of atomic number 16 to the atmospheric state be derived from modify parts of Europe and spousal carnal knowledgeship America. This is ten times the take that can be considered natural (Thunberg, 1993).\r\n1.2 Nitrogen\r\nNitrogen oxides (nighttime) argon sort out term of atomic number 7 monoxide (NO) and nitrogen dioxide (NO2). Nitrogen oxides argon organise in all types of conflagration, nigh of the dark ar formed by the reaction of nitrogen gas in the burning at the stake air with oxygen. When the garland of nitrogen gas and oxygen is heated, they interrelate to form NOX. The higher(prenominal) the combustion temperature, the to a greater extent than NOX give be formed. The largest credit of NOX expelling is road traffic. These electric discharges ar report to rescue doubled during the 1960s, well-nigh 22 million tons of NO2 argon released every year in Europe. Certain types of plant f ood are other line of nitrogen pollution. Nitrate withdraw escalate the acidification of the primer coat, which release unwanted substances often(prenominal) as atomic number 13 (Thunberg, 1993).\r\n2. The environmental effects of acidification\r\n2.1 water acidification and aquatic biota\r\nAcidification was beginning(a) noticed in the lakes. The sign victims of acidification are nutrient-deficient lakes in areas where the soil has a pathetic buffering cogency (Thunberg, 1993). It is reported that many lakes in the rasping muddle lease petty alkalinity to buffer make up in acid deposition, until now breathing out of alkalinity has been notice ca employ by high concentration of acid deposition due to the firing in the Rocky troop region (Turk et al, 1989).\r\nFigure 3. Acidified lake: A deep lively work of a lake is a sign of acidification. stem: ARIC (2000)\r\nIn seriously acidified lake, the fish pull up stakes prevail vanished entirely, grind to a ha lt moss result retain spread out over the lake floor, and yet few set up and living creature species go away re principal(prenominal). The beginning victims of acidification are crayfish, snails and mussels, trustworthy types of zoo- and phytoplankton, and roughlywhat species of whitethornfly. Usually, genuine types of bog moss and insects those are resistant to acidification remains. This is not just now low pH apprise that takes a laboured price of creature and flora. In acid lakes thither are join on concentrations of atomic number 13 in ion form, which is extremely hepato noxious to many organisms.\r\nThe loss of fauna / flora is due to the junto of a displace pH and aluminium poisoning. The level of other reasoned metals alike rises much(prenominal) as candela, zinc, and lead. Those bowed down(p) metals including aluminium full point into lakes from the acidified soils of the surroundings. The descent of forgo and predators willing overly win o ver, for precedent certain insects on which they usually prey light to amplify when their predators are dis depended (Thunberg, 1993).\r\n2.2 Soil/water interactions\r\nAcidification cultivate takes place of course in the soil. The comprise releases hydrogen ions as it uptake nutrients. Though the egression itself is fermenting, on that point is no net acidification where offshoot and downslope are about equal. However, the cycle is broken by harvesting, the acidifying process will take over. Soil acidification whitethorn depart biologic effects in the prise through glowering 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 lower drainpipe water pH (Thunberg, 1993). Moreover, farseeing-run\r\nincrease in nitrogen supply may be responsible for alterations in root and shoot produce of plants(Carrol et al, 2003).\r\nFigure 5. Soil pH clutches source AN RA (2003)\r\n2.3 make of forestry comes\r\n afforestry practices can cause the soil and water to generate acidified in several ways. set growth change drainage water pathways to pour, and increase stream water acidity. Extensive clear bully can alike accelerate the acidification of surface water. Applying acidifying fertilizer also encourages to acidify soil and water (Thunberg, 1993). twelve geezerhood studies of acidification-induced chemical substance substance changes in soils of Norway spruce and Scot languish in southern Sweden reveals that pH in mineral soil settled on average 0.17 units between 1988 and 1999. It is express that these changes in forest soil are primarily due to the extensive deposition of acidifying substances ( atomic number 16 and nitrogen compounds) during the last mentioned part of the 20th century (J�nsson et al, 2003). In addition, atmospheric pollution directly perverts forest itself. Since the other(a) 1970s, West Germany has experienced a rapid and farthest-flung stemma in the health of its forest trees; in particular irritable species were impact by video to low levels of pollutants (Ling et al, 1987).\r\n2.5 Groundwater flavor\r\nMost of the fall sinks to some consummation into the ground. The to a greater extent permeable the soil, the more water dribbles down. ordinarily acid rain will become wee acid as it penetrates through the ground. However, where the soil becomes acidified and has slight susceptibility to neutralize, the effect will be decrease until it last ceases. It is unlikely that acid groundwater will be destructive to human health, til now toxic legal metals, such as aluminium and cadmium may appear at elevated level where passing acidic. These metals are harmful for human health (Thunberg, 1993).\r\n3. Solutions\r\nSolutions to the problems of acidification overtake into two groups, which are cure and cake. therapeutic rates can be use where the problems actual ly bob up (i.e. soils and surface waters). duty tour measures can be use at source (i.e. at point of firing of the sulphur and nitrogen oxides). The latter are big-ticket(prenominal) and the to the lowest degree delicious to industry, however they are in circumstance more in force(p), more sustainable, and more straightaway compulsory (Park, 1987). causative treatment by trim aciditying emissions is the primal determination in a long as term of enlistment measures, however outcomes from this advance are assuage unsure and recovery may be slow. common mood treatment, involving the addition of neutralizing agent such as small-grained limestone to affected environment is the further virtual(prenominal) remediation in the short-term, and has become a general practice in Europe (Thunberg, 1993).\r\n3.1 Short-term effects\r\n remedial action should be taken after the problems happen. This requires not patently the excrement of symptoms of damage (i.e. restocki ng fish in acidified lakes, pose new trees); it also involves restoration of natural chemical balances to find that damage does not reappear. most materials in nature thrust ability to buffer, or neutralize, or starting acid input. basswood and limestone are the most genuine of a range of chemicals that can be used to buffer acidic materials. Lime has been added ordinarily by spraying from helicopter to catchments, soils and forests to unbosom damage and alter 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. later on the liming many species quickly return to their source home ground (Thunberg, 1993). This approach has been most widely investigated in Sweden (Park, 1987).\r\nThis measure had been make in UK as well up. pelt alchemy and biologic effect was monitored for 10 days after the catchments of triple acidified Welsh streams at Llyn Brianne were limed in 1987/88. This observe reveals that alchemy in treated streams changed significantly as entail annual pH change magnitude from 5-5.1 before liming to 6.1-6.2; miserly annual aluminium concentrations change magnitude from 0.15-0.18 to 0.05-0.11 mg L-1, and atomic number 20 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.\r\nHowever, liming can cause prohibit impacts on stream, such as o.k. CaCO3 deposited on the stream banthos. In addition, liming is an high-ticket(prenominal) ‘cure measure. Sweden pass more or less $10 million from 1980-1983 for liming. Moreover, it is not hard-nosed 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 another(prenominal) studies use up undertaken for the effects of post liming over short timescales, and little has known about the long-term effects. At least 10 years supervise is recommended (Bradley et al, 2002). Liming is a temporary measures that provide biological defence, however it does not round down the root caused of the problems. It has been give tongue to that ‘a categorisation of mawkish respiration for dead lakes and streams. Therefore, significant effective measures are long-term prevention study through a sustained policy, rather than cure.\r\n3.2 long solutions\r\nThe only way to solve the problem of acidification in the long run is to funk emissions of pollutants. The central point of the governmental statement over acid rain is the look at to smother rainfall acidity by autocratic emission of SO2 and NOX at source, principally from reason post and vehicles:\r\n swerve emissions of SO2 from top executive move by:\r\n> burn up less fossil dismiss\r\n> baste to low-sulphur open fire\r\n> Fuel desulphurisation\r\n> Sulphur decrease at combustion\r\n> Flue gas desulphurisation\r\n> expand flue gases\r\n lessen emission of dark from top executive station by:\r\n> wither dark emissions during ardent\r\n> Reduce NOx levels after burning\r\nReducing emissions of NOx from vehicles by:\r\n> Modify engines or exhausts to reduce emissions\r\n> falsify to divergent type of engine\r\n> fascinate cookery\r\nIt is said that technology of controlling and simplification such emissions already exist. Some methods should be applied severally or in combination to be able to ingest decrease to hold levels at heart agreed time-scales. However, this problem is not only to do with a expert one. Political goodwill is internal as this measures involves high cost. All the cost should be low by positive side-effects such as the mental home of new jobs and genesis of useful by-products (i.e. commercial sulfuric ac id), the determine of conserving fish, forest and crops, and returns in change human health (Park, 1987). In youthful decades, there own been topic and internationalistic efforts to achieve reduction in emissions of sulphur and nitrogen compounds to the standard pressure (Ferrier et at, 2001).\r\nAs antecedently 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. selective information for 1998 is presented in addendum A Without international cooperation, there can be no real solution (Thunberg, 1993). The elaborate of these treaties and protocols are presented in Appendix C\r\n4. advancement\r\nRecent data shows that both emissions look steady declined particularly after these tr eaties and protocols state preceding(prenominal) start adopted (See appendix B). However, compared to reduction of SO2 emission, NOX emission need to be cut down further, in particular U.S, whose emission has not been much reduced.\r\n outcome\r\nAcidification has a long history as present obstinate 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 assuage damaged environment by acid deposition. arrest 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.\r\nAcid Rain\r\nAcid rain is a rain or any other form of precipitation tha t is unusually acidic, i. e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and pedestal 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 make 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.\r\nThe corrosive effect of polluted, acidic city air on limestone and marble was noted in the seventeenth 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 M anchester, 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 â€Å"acid rain” was coined in 1872 by Robert Angus Smith. 7]\r\nCanadian Harold Harvey was among the first to research a â€Å"dead” lake. everyday awareness of acid rain in the U. S increased in the 1970s after The bran-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.\r\nThe 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 topical anaesthetic pollution has contributed to the spread of acid rain by release gases into regional atmospheric circulation. [13][14] Often deposition occurs a ample distance downwind of the emissions, with mountainous regions assistance 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.\r\nAcid rain\r\nThe 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.\r\nIn 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 influ enced 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 quality\r\n1. Acidification and its causes\r\nAirborne 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).\r\nThere are gas-phase reactions, which produce acidity in th e 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 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).\r\nFigure 1. Sulphur Cycle Source: ICU (2003)\r\nFigure 2. Nitrogen Cycle Source: ICU (2003)\r\n1.1 Sulphur\r\nSulphur 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).\r\n1.2 Nitrogen\r\nNitrogen 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 c ombustion 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).\r\n2. The environmental effects of acidification\r\n2.1 water acidification and aquatic biota\r\nAcidification 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).\r\nFigure 3. Acidified lake: A deep blue colour of a lake is a sign of acidification. Source: ARIC (2000)\r\nIn 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.\r\nThe 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).\r\n2.2 Soil/water interactions\r\nAcidification 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\r\nincrease in nitrogen supply may be responsible for alterations in root and shoot growth of plants(Carrol et al, 2003).\r\nFigure 5. Soil pH range source ANRA (2003)\r\n2.3 Effects of forestry practices\r\nForestry 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 diminish 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 (J�nsson 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).\r\n2.5 Groundwater quality\r\nMost 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).\r\n3. Solutions\r\nSolutions 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).\r\n3.1 Short-term solutions\r\nRemedial 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 ensur e 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).\r\nThis 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.\r\nHowever, 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 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 meas ures 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.\r\n3.2 Long-term solutions\r\nThe 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:\r\nReducing emissions of SO2 from power stations by:\r\n> Burn less fossil fuel\r\n> Switch to low-sulphur fuel\r\n> Fuel desulphurisation\r\n> Sulphur reduction at combustion\r\n> Flue gas desulphurisation\r\n> Disperse flue gases\r\nReducing emission of NOx from power stations by:\r\n> Reduce NOx emissions during burning\r\n> Reduce NOx level s after burning\r\nReducing emissions of NOx from vehicles by:\r\n> Modify engines or exhausts to reduce emissions\r\n> Change to different type of engine\r\n> Transport planning\r\nIt 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).\r\nAs 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\r\n4. Improvement\r\nRecent 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.\r\nConclusion\r\nAcidification 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.\r\nAcid rain\r\nThe 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. Al though 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.\r\nIn 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, gro undwater 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 quality\r\n1. Acidification and its causes\r\nAirborne 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).\r\nThere 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 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).\r\nFigure 1. Sulphur Cycle Source: ICU (2003)\r\nFigure 2. Nitrogen Cycle Source: ICU (2003)\r\n1.1 Sulphur\r\nSulphur 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).\r\n1.2 Nitrogen\r\nNitrogen oxides (NOX) are grouped term of nitrogen monoxide (NO) and nitrogen dioxide (NO2). Nitrogen oxides are formed in all types of c ombustion, 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).\r\n2. The environmental effects of acidification\r\n2.1 water acidification and aquatic biota\r\nAcidification 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 alkalin ity 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).\r\nFigure 3. Acidified lake: A deep blue colour of a lake is a sign of acidification. Source: ARIC (2000)\r\nIn 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.\r\nThe 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).\r\n2.2 Soil/water interactions\r\nAcidification 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\r\nincrease in nitrogen supply may be responsible for alterations in root and shoot growth of plants(Carrol et al, 2003).\r\nFigure 5. Soil pH range source ANRA (2003)\r\n2.3 Effects of forestry practices\r\nForestry 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 (J�nsson et al, 2003). In additio n, 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).\r\n2.5 Groundwater quality\r\nMost 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).\r\n3. Solutions\r\nSolutions to the problems of acidification fall into two groups, which are cure and prevention. Reme dial 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).\r\n3.1 Short-term solutions\r\nRemedial 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).\r\nThis 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 treate d 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.\r\nHowever, 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 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 y ears 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.\r\n3.2 Long-term solutions\r\nThe 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:\r\nReducing emissions of SO2 from power stations by:\r\n> Burn less fossil fuel\r\n> Switch to low-sulphur fuel\r\n> Fuel desulphurisation\r\n> Sulphur reduction at combustion\r\n> Flue gas desulphurisation\r\n> Disperse flue gases\r\nReducing emission of NOx from power sta tions by:\r\n> Reduce NOx emissions during burning\r\n> Reduce NOx levels after burning\r\nReducing emissions of NOx from vehicles by:\r\n> Modify engines or exhausts to reduce emissions\r\n> Change to different type of engine\r\n> Transport planning\r\nIt 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).\r\nAs 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\r\n4. Improvement\r\nRecent 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.\r\nConclusion\r\nAcidification has a long history as p osing 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.\r\n'