Early Intervention for Child with Visual Impairment

Early Intervention for Child with Visual Impairment Discuss the role of early intervention for children with visual impairments Introduction The whole area of visual impairment is a complex and difficult field. Children may either be born with a degree of visual impairment or they may acquire visual impairment at some stage after birth. Some defects may be comparatively obvious and easily detectable other may be very subtle and not obvious for some time. Visual defects may occur as a single lesion or may be part of a larger spectrum of congenital or acquired problems. They can be directly referable to the eye itself, as in the case of infantile cataracts, or may be as a result of more diffuse trauma such as cerebral palsy or perhaps a genetic error of metabolism or even infections such as meningitis. In this essay we intend to consider the role and value of early intervention together with an assessment of the value of screening which is obviously part of the same consideration. The mechanism of examination of the issue will be by means of a critical review of some of the relevant literature which has been recently published on the subject Screening There are many definitions of screening. Perhaps one of the best for our purposes comes from Wald (1) The systematic application of a test or enquiry, to identify individuals at sufficient risk to benefit from further investigation or direct preventive action, amongst persons who have not sought medical attention on account of symptoms of that disorder Screening is a common practice in many areas of the NHS. Whenever it is discussed, it is usually accompanied by prolonged discussions relating to cost-effectiveness and efficacy. With specific regard to visual impairment, screening for conditions that can produce visual impairment at an early age is utterly essential because of the development in early life of the visual processing pathways in the visual cortex (see below). (2) There is a window of opportunity for correction, which rapidly closes depending on the nature and severity of the visual impairment. Because of the dire implications for vision in later life, the cost effectiveness of such screening procedures are seldom applied in this area. This does not mean to say that considerations of efficacy are not valid (see below), but simply that it is not possible to put an appropriate value on a person’s sight. (3) Clearly the purpose of a screening programme is to try to identify those individuals who may be at risk of developing a potentially treatable condition. It is not a diagnostic service. There will usually be both false positives and false negatives. The importance of the National Screening programme is to identify those individuals who would benefit from further specialist assessment. A good place to start is the paper by Rahi (4). This study was designed to consider the efficacy of the screening programme in detecting a comparatively straightforward, although not necessarily easy to detect, lesion – the congenital and infantile cataract. The study was a cross sectional design study with an entry cohort of nearly 250 children under the age of 15 yrs. The object of the exercise was to ascertain the proportion of these children who were detected and treated at 3 months and I year of age. The significance of this study is that it highlights either the difficulty of diagnosis (or possibly the inefficiency of the system) as the results were poor by any interpretation. The paper itself is quite detailed and comprehensive, but the results that are relevant to our considerations in this essay are that only 35% of congenital cataracts were diagnosed at the routine new-born examination and only another 12% had been diagnosed by the time of the 6-8 week examination. Only 57% of the cohort had been seen and assessed by an ophthalmologist by the time they were 3 months old and a further 33% had not been examined or assessed by the time that they were one year old. The authors comment that their study showed that the prime reason for getting an assessment was because of the carer’s concerns in about 40% of all cases. We shall consider the importance of early assessment, accurate diagnosis and appropriate treatment later in this essay, but it is clear from these figures that all three of these eventualities are denied to a very substantial proportion of children and infants with possible adverse consequences for their subsequent visual acuity. In all areas of medicine, we should ideally work from a rational and verifiable evidence base. (5) Given the fact that we can point to evidence that shows that a significant proportion of children with one (at least) visual defect are not routinely detected, we should examine the evidence base for the assumption that early detection is important. For the sake of clarity we will initially confine our considerations to the circumstance of infantile cataract. We do know that infantile cataract is an important and potentially avoidable cause of visual handicap.(6) The resultant stimulus deprivation of the optic tract and visual cortex (7) caused by the inability of the retina to receive normal images, because of the distortion caused by the cataract, produces various degrees of amblyopia.(8) There is a substantial body of evidence to show that in order to optimise the eventual outcome, particularly with the denser forms of cataract, that corrective surgery needs to ideally have been carried out before the age of three months.(9) Because of the developmental importance of the early visual stimulus it is reasonable to assume that the earlier that corrective treatment can be implemented, the better the result is likely to be (10) Although we have initially considered the impact of early screening for the condition of infantile cataract, it follows that other conditions can equally well be screened with the same rationale for early treatment. If we accept that early treatment is the â€Å"gold standard† in childhood visual impairment (11), then it is possible to predict some populations of high risk births that will clearly need increased surveillance. Many of the genetic disorders which can cause visual impairment can be predicted (at least in statistical terms) and the children specifically assessed at birth (12) The majority of the papers examined with regard to infantile cataract are of the same opinion that early treatment is vital to secure any hope of reasonable visual acuity. The evidence base for some other conditions of visual impairment is nowhere near as clear, and in some places, frankly contradictory. If we consider the implications for other conditions of visual impairment in childhood we should consider the paper by Clarke MP (13) which specifically considers the efficacy of treatment of a unilateral visual impairment in the 3-5 yr. old age range. This is particularly relevant to our considerations here because the trial itself was well constructed and has a meaningful outcome. In broad terms, nearly 200 children who were identified as having a degree of unilateral visual impairment were allocated into two groups. One group had â€Å"appropriate treatment† the other had no treatment. The authors note that all children had treatment after the six month observation period. the children who received â€Å"full treatment† with glasses universally had better visual acuity than those who did not receive treatment. Interestingly, the mean treatment effect between the two groups was only one line on the Snellen chart. The degree of improvement was proportional to the degree of original impairment. The specific conclusions of this particular study are worth quoting verbatim:- Treatment is worth while in children with the poorest acuity, but in children with mild (6/9 to 6/12) unilateral acuity loss there was little benefit. Delay in treatment until the age of 5 did not seem to influence effectiveness. It is worth considering these conclusions in more detail as they have distinct relevance to the need for early intervention. The authors point out that there is a tendency for amblyopia to undergo a degree of spontaneous improvement which is consistent with the results of another trial (14). It is also fair to point out that other trials do not concur. Simons K (15) suggest that untreated amblyopia will deteriorate with time. The authors feel that, on balance, they recommend the continued wearing of glasses until the age of 7, even if the visual acuity returns to normal before this time, to prevent the development of refractory amblyopia. (16) When the authors compared the results of their study with children from districts who did not receive pre-school screening, the follow up study showed that deferring their treatment did not limit their potential for improvement and, very significantly, it nearly halved the number of children that needed to wear eye patches at all. (17) On the basis of this evidence the authors felt able to conclude that it is the acuity at presentation rather than the chronological age of the child, that is the most important determinant of eventual outcome. This is consistent with a similar study by Hardman-Lea SJ (18) They actually quantified this by stating that:- Children with a moderate acuity loss of 6/18 or worse showed a clear cut response to treatment, which itself arguably justifies screening to identify and treat these children. In contrast, children with mild acuity loss, who represent over half those identified with unilateral acuity impairment at screening in this and other studies, received little benefit from either treatment. This level of impairment, though often excluded from studies, is still commonly treated in routine clinical practice. We argue that children with 6/9 in only one eye should no longer constitute screen failures and do not justify treatment, even with glasses. Rather disturbingly the trial threw up one (probably statistical) anomaly:- The glasses group with moderate initial acuity, in whom patching treatment was deferred, showed no overall gain in acuity at post-trial follow up. While this is probably a random effect, it raises the question whether prior refractive correction might in some way limit the effectiveness of subsequent patching. Clearly this cannot be regarded as based on firm evidence, but raises the spectre that early treatment may actually be detrimental. If we consider a more technically sophisticated study (19) Weiss A et al 2004) that looked at visually evoked potentials (VERs) in amblyopic children and compared the ages of instigation of treatment (patching) and the detectable effects on the VERs. This is an extremely complex paper but careful weighing and critical analysis of the results shows that, as far as amblyopic children are concerned, the critical window for demonstrating and exploiting cortical neuronal plasticity extends up to the age of ten.( also 20). Although this paper specifically does not comment on the fact, an earlier paper by the same author (21) points to the fact that the plasticity, and therefore adaptability, progressively diminishes from about the age of five onwards The PEDI Group (22) complicate the findings further with their contention that treating amblyopic children in the 3-7 yr. age range did not produce significantly different clinical outcomes when compared to an older age range Screening, in general terms, has been overhauled by the National Screening Committee (23) which has sought to apply the classic Wilson Junger (24) criteria to all aspects of NHS screening. Within the recommendations of this body, various specialist organisations have produced their own guidelines. In the UK, the need for early visual impairment screening is recognised. Clearly this is different from being done efficiently in all cases. The most authoritative guidance that is currently available in this country is that which is based on the recommendations of the two national working parties who produced a joint report. The Royal Colleges of Ophthalmologists and Paediatrics and Child Health (25) The current recommendations include an inspection of the eyes together with an evaluation of the red reflex at birth and then a fuller assessment which would include an examination for the presence of squint and visual behaviour generally at about 6-8 weeks. (26) Later on in childhood there are other specified screening procedures which are designed to detect abnormalities such as strabismus, abnormalities of colour vision and reduced visual acuity although an examination of the literature would suggest that the pick up rate is surprisingly small (27). This particular author suggests this is mainly because the vast majority of cases are brought to the attention of the primary healthcare teams by the carers before screening is carried out. In this essay we have conducted a brief overview of some of the relevant literature in the field of early detection of visual impairment. The results are disappointingly confusing. Some areas appear to have a fairly clear cut and universal agreement, others seem to produce well constructed studies that offer seemingly mutually exclusive results. (28). The area of the infantile or congenital cataract appears to be one of those areas where there is fairly universal agreement that early treatment is beneficial, but the biggest stumbling block appears to be the comparative inability to pick up or detect the abnormality in a clinical screening setting. Although we have not presented firm evidence, as it is not directly relevant to our discussions, there is also the problem that surgical intervention, although obviously helpful in terms of preserving vision, may actually have a down side that iatrogenic glaucoma is a possibility in later life. (10) The converse situation appears to apply to the amblyopic patient, or the patient with strabismus. We have presented evidence that appears to be frankly contradictory. Although it appears easier to detect these abnormalities in the older child there is considerable disparity in opinion about whether early treatment is either beneficial, or in the case of one of the papers presented, even helpful. It is clearly difficult to form an opinion with any sort of firm evidence base in these circumstances. Although it is reassuring to read a paper and find that the authors call for â€Å"more research to be done† in that particular area, it does not help those practitioners currently working in the clinical field, to come to a firm view on whether early treatment is either indicated, useful or even necessary in these particular circumstances. References Wald NJ. Guidance on terminology. J Med Screen 1994;1:76. Barnes GR, Hess RF, Dumoulin SO, Achtman RL, Pike GB. The cortical deficit in humans with strabismic amblyopia. J Physiol. 2001;533:281–297 National Screening Committee. First report of the National Screening Committee. Health Departments of the United Kingdom, 1998. (4) Jugnoo S Rahi and Carol Dezateux National cross sectional study of detection of congenital and infantile cataract in the United Kingdom: role of childhood screening and surveillance BMJ, Feb 1999; 318: 362 365 (5) Berwick D 2005 Broadening the view of evidence-based medicine Qual. Saf. Health Care, Oct 2005; 14: 315 316. (6) Foster A, Gilbert C. Epidemiology of visual impairment in children. In: Taylor D, ed. Paediatric ophthalmology. 2nd ed. London: Blackwell Science, 1997:3-12. (7) Taylor D. Congenital cataract: the history, the nature and the practice. The Doyne lecture. Eye 1998; 12: 9-36 (8) Campos E. Amblyopia. Surv Ophthalmol 1995; 40: 23-39 (9) Lloyd IC, Dowler JGF, Kriss A, Speedwell L, Thompson DA, Russell-Eggitt I, et al. Modulation of amblyopic therapy following early surgery for unilateral congenital cataracts. Br J Ophthalmol 1995; 79: 802-806 (10) M Vishwanath, R Cheong-Leen, D Taylor, I Russell-Eggitt, and J Rahi Is early surgery for congenital cataract a risk factor for glaucoma? Br. J. Ophthalmol., July 1, 2004; 88(7): 905 910. (11) Barrett BT et al. 2004 B. T. Barrett, A. Bradley, and P. V. McGraw Understanding the Neural Basis of Amblyopia Neuroscientist, April 1, 2004; 10(2): 106 117. (12) Committee on Practice and Ambulatory Medicine Section on Ophthalmology. Eye examination and vision screening in infants, children and young adults. Pediatrics 1996; 98: 153-157 (13) M P Clarke, C M Wright, S Hrisos, J D Anderson, J Henderson, and S R Richardson Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening BMJ, Nov 2003; 327: 1251 ; (14) Hard AL, Williams P, Sjostrand J. Do we have optimal screening limits in Sweden for vision testing at the age of 4 years? Acta Ophthalmol Scand 1995;73: 483-5 (15) Simons K, Preslan M. Natural history of amblyopia untreated due to lack of compliance. Br J Ophthalmol 1999;83: 582-7. (16) Kutschke P, Scott W, Keech R. Anisometropic amblyopia. Ophthalmology 1999: 258-63 (17) World Health Organization. Elimination of avoidable visual disability due to refractive errors. Geneva: WHO, 2000. (18) Hardman-Lea SJ, Loades J, Rubinstein MP. The sensitive period for anisometropic amblyopia. Eye 1989;3: 783-90 (19) AH. Weiss and J. P. Kelly Spatial-Frequency-Dependent Changes in Cortical Activation before and after Patching in Amblyopic Children Invest. Ophthalmol. Vis. Sci., October 1, 2004; 45(10): 3531 3537. (20) Barnes G, Hess R, Dumoulin S, Achtman R, Pike G. The cortical deficit in humans with strabismic amblyopia. J Physiol 2001;533: 281-97. (21) Weiss AH. Unilateral high myopia: optical components, associated factors, and visual outcomes. Br J Ophthalmol. 2003;87:1025–1031. (22) PEDI Group 2002 Pediatric Eye Disease Investigator Group. The clinical profile of moderate amblyopia in children younger than 7 years. Arch Ophthalmol. 2002;120:281–287. (23) National Screening Committee. First report of the National Screening Committee. Health Departments of the United Kingdom, 1998. (24) Wilson JMG, Jungner G. Principles and practice of screening for disease. Geneva: World Health Organisation, 1968. (25) Royal Colleges 1994 Royal College of Ophthalmologists and British Paediatric Association. Ophthalmic services for children. Report of joint working party. London: RCO, BPA , 1994. (26) Hall DM. Health for all children. 3rd ed. Report of the third joint working party on child health surveillance. Oxford: Oxford University Press , 1996. (27) Snowdon SK, Stewart-Brown SL. Preschool vision screening. Health Technol Assess 1997;1:i-83. (28) Clare Gilbert and Haroon Awan Blindness in children BMJ, Oct 2003; 327: 760 – 761 18.11.05 PDG Word count 3,010

Local or National Issue

In this essay, an attempt will be made to assess the important issue: ‘America’s dependence on foreign oil’.   In the context of steeply rising oil prices, it is important that the American government devises strategy to reduce its dependence on foreign oil. The USA is one of most developed countries in the world and it has been using large amount of oil resources. There has been increase in the demand for oil from the American citizens. Oil is essential for the economic progress of any nation in the modern world. However, America is not self-sufficient in the oil production. This would mean that it needs to import huge quantity of oil from the foreign countries particularly the Islamic countries in the Middle East. At the same time the American president has declared a ‘war on terror’ particularly on the Islamic terrorists. The Islamic terrorists have not taken this declaration lightly and this is proved by their continued attack on the American embassies and people all over the world. The Islamic countries possess huge reserves of oil. The lack of huge oil reserve is the main limitation of the American economy. This limitation has been utilized by the anti American terrorist groups.   The American government has been importing huge amount of oil from the foreign countries and in the process it has been paying huge amount of dollars to the Islamic countries. One can suggest that this dependence of America on foreign oil has encouraged the Islamic terrorist activities as they obtain the American dollars directly or indirectly through the sale of oil to America. This would imply that the American government has been paying to the terrorist groups to indulge in anti-American activities. For example, it is well known that Osama bin Laden obtained financial support from contributions from the Islamic nations. This has limited the ability of the American government to fight against terrorism. The American dependence on foreign oil also has affected the American economy particularly due to the great increase in the price of oil. The oil producing nations enjoy monopoly over the oil production and sale. They can control the oil price and its supply. This has reduced the autonomy of America in world politics. The American government needs to avoid the repetition of the terrorist attacks on the American nation. For this, Americans need to enjoy energy self-sufficiency. (Gal, 2004) The government and the people can contribute to the oil self-sufficiency by reducing oil consumption. The government needs to encourage the scientists to develop alternative energy resources. For example, recently the scientists have found that oil can be replaced by energy resources such as electricity, ethanol, bio-diesel, hydrogen fuel and such other alternative fuels. Already, a few cars which can use alternative fuels have been produced by the American car manufacturers. The government needs to encourage the consumers to use such alternative fuels in their cars in order to improve the financial strength of the country. This would also reduce the financial strength of the Islamic terrorist organizations as they mostly depend on the American dollars in the form of oil exports to America. The government should introduce legislations to provide incentive to alternative fuel producers and consumers so that in all the provinces of the USA people would become aware of the need to save precious American dollar in order to fight the war against terror. By introducing such alternative fuels in the cars, it is possible to save huge amount of dollars which otherwise would have been spent for the purpose of purchasing oil from the foreign countries. Alternative fuel production plants also would lead to improved economic condition of America. This shows that the American government needs to establish oil independence. Bibliography Luft, Gal. (October 2004). Ending America’s Dependence on Middle East Oil. The Middle East Forum Protecting American Interests. Retrieved 31 March 2006 from   

Fresh Water Essay

1. Introduction Fresh water is an indispensable resource for human livelihood, agricultural irrigation and economic development (Brooks, 2007). However, due to the rapid population growth and the limited reserves, increasing regions have faced serious scarcity of fresh water (Williamson, 2010). Saudi Arabia is one of the driest countries in the world (CIA, 2011). According to World Bank (2011), the world average fresh water consumption is nearly 7000m ³/year/person, while the water resource per capita in Saudi Arabia is less than 1200m ³/year/person. In order to satisfy the demand for water, Saudi Arabia currently supplies fresh water via deep drilling of fossil groundwater (UNESCO, 2009). Nevertheless, society increasingly recognises that those water resources are non-renewable and are liable to be reduced by the overexploited boreholes and wells. Thus Saudi Arabia needs to find alternative and sustainable methods to solve these issues. Since there is abundant sea water around Saudi Arabia, large-scale desalination could be the ideal solution to water scarcity. However, the expensive cost and the detrimental influence on the environment might limit the scale and sustainability of this method. Due to the cheap cost and the minor environmental damage, wastewater reuse is regarded as another potential solution. However, it seems to have a low social acceptance. Therefore, this report will compare the feasibility of desalination and water reuse in terms of cost, social acceptance and environmental impacts, thereby exploring the most suitable method to deal with the scarcity of water in Saudi Arabia. 2. Background Saudi Arabia is located in the Middle East, bordering the Persian Gulf and the Red Sea (CIA, 2011). It is famous for the abundant reserves of oil and gas. However, the fresh water resources in Saudi Arabia are very limited. According to World Bank (2011), there is no one river and lake with perennial water throughout this country. Furthermore, due to the influence of the subtropical climate, the annual precipitation is only about 100 mm and the climate is hot and dry (ibid.). Additionally, rapid population growth has caused higher increase of demand for water (Abderrahman, 2000). Shortages of water have constrained the development of agriculture and economy (Williamson, 2010). Since the underground water is estimated to be able to supply for 320 years, the underground water is still the principal source of water at present (UNESCO, 2009: 100). However, with the increasing awareness of defects of this method, the focus of the future development of water provision has shifted to other sustainable water technologies. In order to deal with fresh water shortages, desalination has received enormous investments. According to Abu-Arabi (2007), in 2004 the number of desalination industries reached 30 and they can supply 1.1 billion cubic metres of fresh water per year. Wastewater reuse is regarded as another future means of water provision. According to Bashitialshaaer et al (2009), in 2009 there were 33 wastewater treatment plants with a capacity of 748 billion cubic metres per year. 3. Requirements Cost should be the principal consideration of water provision because an expensive cost might limit the scale of application of methods. This also includes the cost of energy consumption. Social acceptance plays a significant role in the development of water supply technologies. If the water cannot be accepted by society, it will lead to very little consumption. Environment has a profound influence on human beings. In order to prevent water supply technology undermining the environment, its impacts on the environment should be considered. 4. Presentation of options 4.1 Desalination Desalination is â€Å"a specific treatment process to take minerals from saline water to purify for drinking water and irrigation† (Al-Sahlawi, 1999). Sometimes this process is used to take salinity and other pollutants from wastewater. The general method of desalination is reverse osmosis or multi-stage flash distillation (Lone Star Chapter of the Sierra Club, 2008). 4.2 Water Reuse Water reuse means treating wastewater to a specific quality, and then using treated or reclaimed water from one application for another application (McKenzie, 2005; Asano, 2006). The resources for wastewater reuse are various; according to Asano (2006), they could be domestic wastewater, industrial sewage, municipal sewage or agricultural wastewater. 5. Comparison of Options 5.1 Cost Although the cost of desalination has decreased dramatically in the past three decades, it is still expensive to use in large scale. Alghariani (2003) points out that the expenditure of desalination consists of initial investment for equipment, running costs (including staff and maintenance), as well as chemicals or specialised parts. At present, according to the Third World Water Assessment Report (UNESCO, 2009: 155), the average cost of desalination is between $0.60/m ³ and $0.80/m ³. Moreover, Owens and Brunsdale (2000, cited in Alghariani, 2003: 5) claim that the cost of desalination in Florida can even be less than $0.55/m ³, which is one-tenth of the cost price in 1979. However, as Wright (2009) points out, this cost is still higher than other water supply technologies. Apart from expenditure, desalination is generally considered a high-cost process due to the enormous energy consumption (Abu-Arabi, 2007). Nevertheless, this does not seem to be a problem for Saudi Arabia. According to the CIA (2010), the proven oil and gas reserves in Saudi Arabia are respectively the first and fifth in the world. As Abu-Arabi (2007) points out, in Saudi Arabia the annual solar energy received by each square kilometre of land is equivalent to 1.5 million barrels of crude oil. Abundant energy may lead to a low price. Nevertheless, oil is non-renewable and oil reserves are estimated to last less than one century (World Energy Council, 2010), so the consumption of energy should be taken into account as a considerable cost. Moreover, the treatment of the waste gas generated by desalination also increases the cost (Al-Sahlawi, 1999). The cost of water reuse is influenced by various factors such as treatment level, intended reuse options, location of treatment, wastewater collection and transportation. According to Qadir et al (2009), the average cost of recycling water is approximately $1.79 per cubic metre. However, compared to desalination, wastewater reuse has the advantage of cost. Fryer (2010) demonstrates that the relative marginal cost of seawater desalination is higher than water recycling, and amounts to up to $2000 per acre-foot. The water recycling represented a general fluctuation pattern between approximately $300 and $1000 per acre-foot (Fryer, 2010). Even so, water recycling appears cheaper than desalination. 5.2 Social acceptance While both options can generate safe water, desalination seems to have higher social acceptance. Sloane (2009) investigated the acceptance of desalination and water reuse at Nourieh Palms. As shown in Table 2, in all areas but particularly drinking water, the approval rate for desalination is higher than water reuse. This reflects that more people trust the quality of water which is generated by desalination. Source: Sloane (2009: 128) For most uses, reclaimed water tends to have lower social acceptance than desalination. There are various reasons why people do not trust reclaimed water. First, most people do not understand the difference between treated and untreated water (McKenzie, 2005). Secondly, they are often concerned about the type of wastewater, treatment levels and the availability of information (Qadir, 2009). There are particular concerns with the wastewater produced by the petroleum industry, brought to the surface when drilling oil. This kind of wastewater is difficult to treat due to the high content of oil (Asatekin and Mayes, 2009). Therefore, though reclaimed water undergoes a very thorough treatment process which makes it entirely safe to drink, the public are reluctant to drink treated sewage. However, it is not impossible that people will accept drinking such treated sewage. For example, Singapore has successfully used reclaimed water, a product named NEWater, to supply drinking water (Tortajada, 2006). This reflects that treated wastewater could become widely accepted through public education. 5.3 Influence on environment There are some environmental disadvantages of desalination. Since Saudi Arabia is rich in oil and gas, clean energy such as solar energy tends to be used less than fossil energy (Al-Sahlawi, 1999). The overuse of fossil energy may cause serious environmental pollution. For instance, oil might generate large quantities of carbon dioxide, which is the main factor leading to global warming (Al-Aza, 2005). Furthermore, the gas emissions from oil could undermine the ozone layer and cause acid rain (ibid.). In addition to environmental pollution caused by fossil energy, brine discharge is another serious problem. After desalination, the brines generally have a higher concentration of salt, nearly twice that of natural seawater (Tsiourtis, 2002). The brines are generally discharged back to the same place where the seawater comes from. This might lead to increased concentration of salt in the sea, which is a potential threat to aquatics. In contrast with the desalination, wastewater reuse is regarded as an eco-friendly way to supply fresh water. Recycling water can maximise the use of rainfall and other current water resources so that the limited underground water resources can be conserved (Miller, 2005). In the meantime, decreased energy consumption could reduce the pollution caused by the use of fossil energy (Ghermandi et al, 2007). Therefore, recycled water is a sustainable and eco-friendly method to supply good quality fresh water. 6. Conclusion From the information given above, the following conclusions can be drawn: 1) Both desalination and wastewater reuse are feasible water supply technologies. 2) The cost of desalination has decreased dramatically, but is still far more than water reuse. Desalination requires more capital and energy. 3) Reclaimed water has low public acceptance, especially for drinking water. 4) Desalination could undermine the environment, while water reuse is eco-friendly. 7. Recommendation Considering the cost and the impact on the environment, wastewater reuse is recommended to be used as the main water supply technology. Although the public acceptance of recycled water is lower than desalination, the example of Singapore has proven that reclaimed water could be accepted in daily life. Desalination is a costly water supply technology. Furthermore, it needs a vast amount of energy. Even if Saudi Arabia has abundant oil and gas reserves, as these resources are non-renewable, desalination is not suitable for sustainable water supply. Additionally, it has detrimental influences upon the environment. Therefore, Saudi Arabia should improve the ratio of wastewater reuse in the whole fresh water supply system. 8. References Abderrahman, W. (2000). Urban Water Management in Developing Arid Countries. Water Resources Development 16 (1) pp7-20. Abu-Arabi, M. (2007). Status and Prospects for Solar Desalination in the Mena Region. In Rizzuti, L., Ettouney, H., and Cipollina, A. (eds.) Solar Desalination for the 21st Century: A Review of Modern Technologies and Researches on Desalination Coupled to Renewable Energies (pp163-178). Dordrecht: Springer. Al-Aza, M. (2005). Oil Pollution and Its Environmental Impact in the Arabian Gulf Region. Boston: Elsevier. Alghariani, S. (2003). Water Transfer Versus Desalination in North Africa: Sustainability and Cost Comparison. London: School of Oriental and African Studies. Al-Sahlawi, M. (1999). Seawater Desalination in Saudi Arabia: Economic Review and Demand Projections. Desalination (123) pp143-147. Asano, T. (2006). Water Reuse: Issues, Technologies and Applications. New York: McGraw Hill. Asatekin, A. And Mayes, A. (2009). Oil Industry Wastewater Treatment with Fouling Resistant Membranes Containing Amphiphilic Comb Copolymers. Evrion. Sci. Technol. 43 (12) pp. 4487-4492. Bashitialshaaer, R., Persson, K., and Larsson, M. (2009). Estimated Future Production of Desalinated Seawater in the MENA Countries and Consequences for the Recipients. Dubai: IDA World Congress. Brooks, D. (2007). Fresh Water in the Middle East and North Africa. In Lipchin, C., Pallant, E., Saranga, D. And Amster, A. (eds.) Water Resources Management and Security in the Middle East (pp. 33-64). Dordrecht: Springer. CIA (2011). Saudi Arabia. Retrieved 5 April 2011 from https://www.cia.gov/library/publications/the-world-factbook/geos/sa.html Fryer J. (2010). An Investigation of the Marginal Cost of Seawater Desalination in California. Retrieved 5 April 2011 from http://r4rd.org/wp-content/uploads/2009/07/Cost_of_Seawater_Desalination__Final_3-18-09.pdf Ghermandi, A., Bixio, D. And Thoeye, C. (2007). The Role of Free Water Constructed Wetlands As Polishing Step in Municipal Wastewater Reclamation and Reuse. Science of the Total Environment. 380 (1-3) pp. 247-258. Lone Star Chapter of the Sierra Club (2008). Desalination: Is It Worth the Salt?. Retrieved 5 April 2011 from http://texas.sierraclub.org/press/Desalination.pdf McKenzie, C. (2005). Wastewater Reuse Conserves Water and Protects Waterways. On Tap Winter 44 (4) pp46-51. Miller, G. (2005). Integrated Concepts in Water Reuse: Managing Global Water Needs. Desalination 187 (1-3) pp. 65-75. Tsiourtis, N. (2002). Desalination and the Environment. Desalination. 141 (3) pp. 223-236. UNESCO (2009). The United Nations World Water Development Report, 3: Water in a Changing World. Paris and London: Earthscan. Qadir, M., Bahri, A., Sato, T., and Al-Karadsheh, E. (2009). Wastewater Production, Treatment and Irrigation in the Middle East and North Africa. Biomedical and Life Science 24 (1-2) pp37-51. Sloane, T. (2009). Water Provision: A Comparative Analysis. London: Sage. Tortajada, C. (2006). Water Management in Singapore. International Journal of Water Resources Development (22) pp. 227-240. Williamson, F. (2010). Water Management: Traditional and Alternative Approaches. International Resource Management. 15(2) pp. 227-231. World Bank (2011). Saudi Arabia. Retrieved 5 April 2011 from http://data.worldbank.org/country/saudi-arabia World Energy Council (2010). Issues. Retrieved 5 April 2011 from http://worldenergy.org/Issues Wright, G. (2009). The Economic Feasibility of Desalination for Water Supply to Arid Regions. Global Water Issues 13 (2) pp202-206.

The Effects Of Kerosene On The Modern Society - 1859 Words

In today’s modern society fuel is used by a large percentage of the population whether it is for transport, electricity generation or industrial and domestic use. A fuel is a combustible substance that is capable of releasing energy. Many of the fuels used today release copious amounts of harmful gases into the environment and are obtained from sources that will take millions of years to replenish and because of this a new fuel is needed to replace petrol. Kerosene is an oil distillate commonly used as a fuel or solvent. It can be extracted from coal, oil shale and wood however is primarily obtained from refined petroleum. Kerosene was once the most used fuel for lighting before the introduction of electricity. In terms of environmental effects, kerosene produces fewer fumes than other fossil fumes. Despite this, it does emit some poisonous gases including nitrogen dioxide, sulphur dioxide and carbon monoxide, all of which are capable of causing damage to the body if breathed in. Alternatively ethanol could be used as a replacement for kerosene for use in a jet engine. The use of ethanol as opposed to kerosene would reduce carbon dioxide emissions, provided that a renewable energy source was used to produce crops and to distil fermented ethanol. In addition to this ethanol is a renewable source unlike kerosene thereby eliminating the concern of this source running out. Also the presence of oxygen in the ethanol molecule means that combustion is almost always complete.Show MoreRelatedEssay Indian Culture in A Stench of Kerosene1436 Words   |  6 PagesComment on what view of Indian culture is portrayed in A Stench of Kerosene giving your own personal response. A Stench of Kerosene , authored by the pen of Amrita Pritam, is a tale of suffering and injustice in the rural areas of India. The author tries to relate the life of a young Indian wife to the reader in such a way that it leaves them feeling pity and remorse for her. 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