Environmental Disasters and Their Impact on a Human - Coursework Example

Running Head: Environmental Disasters Environmental Disasters Inserts His/Her Inserts Grade Inserts Name 09 October 2009 Environmental disasters have a great negative impact on environment and a man. Chernobyl accident was one of the most terrible and awful disasters in human history. At 01.23 local time on 26 April 1986, the Chernobyl No. 4 reactor accelerated from a fraction of full power to 100 times full power in just 4 seconds, causing an explosive generation of steam. The details of what happened internally as a result of this surge are described in Section 3, but the explosion lifted the enormous 1000 tonne roof off the building, tipping it on to its side, and spewed burning debris over the site. Since the reactor had been in full use for well over 2 years, the core content was rich in a wide range of fission products, many of which were highly active. Two of the most important from a health point of view were iodine-131 and caesium-137 (Alexievich and Gessen 2006). That part of the material which became airborne would have risen due to the intense heat associated with the very large quantities of energy released during the explosion. Nevertheless some would be in the form of large particulates and would have fallen out under gravity to be deposited within a few kilometers of Chernobyl. This local loss makes the assessment of the total release on the first day somewhat tentative. Enormous efforts, not to mention courage, were expended to contain the release of active material to the atmosphere and to ground waters. About 5000 tonnes of boron carbide, dolomite, sand, clay and lead were dumped on top of the reactor from helicopters. As a result, by day 5 the emissions had fallen by 90%, but later rose again since the residual power of the fuel heated the debris to over 2000 °C, resulting in partial penetration of the dumped covering material. By 5 May emissions were up to a third of the level of day 1, 26 April. However, by the following day workers had managed to cool the core and emissions virtually ceased. Even so, small detectable traces were sensed in the atmosphere for at least another 3 months in Europe (Medvedev 1992). The meteorological situation during the release was fairly complex and variable with winds that carried the activity successively over almost all parts of Europe. At the time of the explosion on 26 April a ridge of high pressure was centred over northwest Russia, whose wind circulation carried the upper part of the plume away towards the Baltic and Scandinavia. Nearer the ground, the clear skies had resulted in cold ground and a temperature inversion reaching up to some 500 m. Within this stable layer there was almost a calm, but above it the winds picked up to 10 m/s and more. After sunrise, the stable layer broke down and the low-level winds increased (Mould, 2000). Two staff died immediately in the accident, either in the explosion or in the subsequent fire. Twenty-nine others died in the following few days as a result of intense β-exposure causing extensive radiation burns of the skin (Mould, 2000). Two hundred and seventy-one other people were admitted to hospital of whom 174 suffered symptoms of acute radiation syndrome, having received whole-body γ-irradiation doses between 2 and 16 gray. One hundred and thirty-five thousand people were evacuated from a zone within 30 km of Chernobyl. None of these people showed any clinical symptoms, although it is estimated that up to 1000 of them may develop cancers in the next few decades (Alexievich and Gessen 2006). Once the plume reached Scandinavia, it split into three areas. One moved away to the east across northern parts of the USSR into Japan and China. A second crossed central Norway and out into the Norwegian Sea and moved towards North America. Heavy rain on 28 April resulted in very large depositions of activity in some parts of Scandinavia. A third wave moved south-westwards in response to a transient ridge of high pressure over the North Sea. A part of this plume crossed central Europe, moved over northern Italy and southern France, and then turned north-westwards as the ridge slipped away to the NE, reaching the French north coast late on Thursday, 1 May (Mould, 2000). The disasters influenced environmental conditions and human health. The deposition of activity to the ground is the result of two main processes, termed dry deposition and wet deposition. Dry deposition covers the combined effect of sedimentation of larger particles under gravity, of impaction of particulates and aerosols on leaves, etc., and of absorption of reactive gases by the soil and vegetation (Mould, 2000).Wet deposition is linked with atmospheric water droplets and combines the effects of rain and snow as well as the impaction of wind-blown contaminated cloud or fog droplets on to vegetation when the cloud or fog extends down to the surface. The removal by rain or snow is particularly efficient; just 1 mm of rain can remove more material than can be deposited by dry deposition operating over 24 hours (Walker, 2006). Deposition may be underestimated in the more mountainous areas for two reasons: (i) the rain-gauge sites in these areas are often remote and were not read on a daily basis over the weekend; and (ii) the sites are usually in valleys and wet deposition would normally be less there than on the neighboring mountain tops. The deposition of iodine-131 was broadly similar to that of caesium-137 except for the higher additional dry deposition component, being roughly double in overall magnitude in the wet areas and down to about 400 Bq/m2 in the dry areas where dry deposition dominated (Walker, 2006). In various parts of Europe, analyses of the levels of activity in drinking water, milk, vegetables and meat revealed levels approaching or above national emergency levels in one or more species. Consequently governments imposed restrictions on the sale or use of these species, often causing hardship and loss of revenue to the farmers concerned (Alexievich and Gessen 2006). Beyond 100 km from Chernobyl, the effects of the additional uptake of radioactivity into the human population are likely to be so small that they will be impossible to detect even by the most careful of medical surveys over the next few decades. This simple truth was largely ignored by the media and has led to considerable anxiety and exaggerated fear of the nuclear industry(Mould, 2000). On the other hand, some deaths may well result, although how these should be interpreted is a matter of some debate: for example, many may occur in old people nearing the end of their lives anyway. This is not intended to sound callous: any death is a tragedy to the people concerned; but it is intended to put the problem in perspective (Walker, 2006). It is possible to say that the disaster could have been avoided if the country and the government paid more attention to its nuclear power stations and responded to risk situations on a timely manner. It is known that the power station authorities had reported serious problems and risks before the accident but the state neglected all of the reports. In general, the Soviet reports on the Chernobyl accident gave little information about the stations Emergency Arrangements or whether these had been implemented. Representatives from the USSR were on the Senior Advisory Group of specialists in the IAEA who produced the safety guides for these arrangements(Mould, 2000). The consequences of the accident were so severe that it was beyond the capability of the station management and personnel resources. Little was done to control the situation until the arrival of massive national government assistance. Public concern and political pressures suggest that a senior government minister should be appointed to manage the emergency arrangements in the event of a major release of activity to the environment which might involve the short term evacuation of the public in the vicinity of the NPS and lead to restrictions on food, milk and water supplies and the extensive clean-up operations following the accident. This may involve the cooperation and control of a number of government departments together with national and local agencies (Walker, 2006). Notification of nuclear accidents, whether from NPS (nuclear power stations) or other nuclear installations, especially those resulting in the release of radioactivity to the environment, should be immediately notified not only to the national regulatory authorities, but also to the international advisory authorities. This will enable those countries likely to be affected by the activity released to take appropriate countermeasures so as to reduce the consequences of such an event. Emergency exercises should be more realistically planned, especially with respect to the simulation of plant damage and real time scales extending overnight. Reactor simulators, where these are available on NPS, should be used to portray the postulated accident situation to which the operators would be required to respond (Walker, 2006). In sum, the accident at the Chernobyl No. 4 reactor was undoubtedly the most serious single international environmental pollution incident that has occurred in the world to date, although it could be argued that the continuous emission of acidic gases from fossil fuel combustion and other sources constitutes a greater overall international environmental problem. Above all, the political divisions between East and West, resulting in the absence of any participation by Eastern Bloc countries in international liability compensation arrangements (in themselves currently inadequate), and the confusions over differing national foodstuff intervention standards prevented effective resolution of the secondary and longer term consequences of the accident. The conclusion of the early notification and mutual assistance agreements of the IAEA is an obvious advance on the pre-existing situation, and it is likely that the international dispersion monitoring and modelling system is now more developed as a result of the increased attention devoted to it. However, many of the international agreements necessary for an effective incident control and response system are still wanting nearly two years after the accident at Chernobyl. It remains a fact that even if these were to be put into place in the near future, the efficacy of international arrangements for nuclear incidents would only be established when tested by occurrence of a real world incident. References Alexievich, S., Gessen,K. (2006). Voices from Chernobyl: The Oral History of a Nuclear Disaster. Picador. Medvedev, Z. A. (1992). The Legacy of Chernobyl. W.W. Norton & Co.. Mould, R.F. (2000). Chernobyl Record: The Definitive History of the Chernobyl Catastrophe. Taylor & Francis; 1 edition. Walker, S. J. (2006). Three Mile Island: A Nuclear Crisis in Historical Perspective. University of California Press; 1 edition. Read More