Chernobyl disaster effects
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- This article is about the effects of the Chernobyl disaster, for the main article on the disaster see: Chernobyl disaster
The Chernobyl disaster triggered the release of substantial amounts of radiation into the atmosphere in the form of both particle and gaseous radioisotopes, and is the most significant unintentional release of radiation into the environment to date. The International Atomic Energy Agency (IAEA) alleges that, while the Chernobyl disaster released as much as 400 times the radioactive contamination of the Hiroshima bomb, it was 100 to 1,000 times less than the contamination caused by atmospheric nuclear weapons testing in the mid-20th century. The effects of this release of radioisotopes are the subject of substantial study, and the full effect of the radiation will not be understood for some time. Ukraine, Belarus and Russia were affected by the radioactive contamination due to the radioactive cloud, as were Germany, Norway, Sweden, Austria, Italy, France and the United Kingdom. Due to the sensitive nature of nuclear-related issues, it has been difficult for the public to appreciate the full extent of the catastrophe. Scientific studies are incomplete in part because of political concerns (for example, in Belarus, Yuri Bandazhevsky, a scientist criticizing the official research being conducted into the Chernobyl disaster was jailed for four years).
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[edit] Short-term health effects and immediate results
The explosion at the power station and subsequent fires inside the remains of the reactor provoked a radioactive cloud which flew over Russia, Belarus and Ukraine, as well as Germany, Norway, Sweden, Romania, Austria, Italy, France and the United Kingdom (UK). In fact, the initial evidence in other countries that a major exhaust of radioactive material had occurred came not from Soviet sources, but from Sweden, where on April 27 workers at the Forsmark Nuclear Power Plant (approximately 1100 km from the Chernobyl site) were found to have radioactive particles on their clothes. It was Sweden's search for the source of radioactivity, after they had determined there was no leak at the Swedish plant, that led to the first hint of a serious nuclear problem in the Western Soviet Union. In France, the government then claimed that the radioactive cloud had stopped at the Italian border. Therefore, while some kind of food were prohibited in Italy because of radioactivity (in particular mushrooms), the French authorities didn't take any such measures, in an attempt to appease the population's fears (See below).
Contamination from the Chernobyl disaster was not evenly spread across the surrounding countryside, but scattered irregularly depending on weather conditions. Reports from Soviet and Western scientists indicate that Belarus received about 60% of the contamination that fell on the former Soviet Union. A large area in Russia south of Bryansk was also contaminated, as were parts of northwestern Ukraine.
203 people were hospitalized immediately, of whom 31 died (28 of them died from acute radiation exposure).[citation needed] Most of these were fire and rescue workers trying to bring the disaster under control, who were not fully aware of how dangerous the radiation exposure (from the smoke) was (for a discussion of the more important isotopes in fallout see fission products). 135,000 people were evacuated from the area, including 50,000 from the nearby town of Pripyat, Ukraine. Health officials have predicted that over the next 70 years there will be a 2% increase in cancer rates in much of the population which was exposed to the 5-12 (depending on source) EBq of radioactive contamination released from the reactor. An additional 10 individuals have already died of cancer as a result of the disaster.[citation needed]
Soviet scientists reported that the Chernobyl Unit 4 reactor contained about 180-190 metric tons of uranium dioxide fuel and fission products. Estimates of the amount of this material that escaped range from 5 to 30 percent, but some liquidators, who have actually been inside the sarcophagus and the reactor shell itself — e.g. Mr. Usatenko and Dr. Karpan[citation needed] — state that not more than 5-10% of the fuel remains inside; indeed, photographs of the reactor shell show that it is completely empty. Because of the intense heat of the fire, much of the ejected fuel was lofted high into the atmosphere (with no containment building to stop it), where it spread.
[edit] Workers and liquidators
The workers involved in the recovery and cleanup after the disaster, called "liquidators", received high doses of radiation. In most cases, these workers were not equipped with individual dosimeters to measure the amount of radiation received, so experts can only estimate their doses. Even where dosimeters were used, dosimetric procedures varied. Some workers are thought to have been given more accurate estimated doses than others. According to Soviet estimates, between 300,000 and 600,000 people were involved in the cleanup of the 30 km evacuation zone around the reactor, but many of them entered the zone two years after the disaster.[1] Estimates of the number of "liquidators"—workers brought into the area for disaster management and recovery work—vary; the World Health Organization, for example, puts the figure at about 800,000; Russia lists as liquidators some people who did not work in contaminated areas. In the first year after the disaster, the number of cleanup workers in the zone was estimated to be 211,000, and these workers received an estimated average dose of 165 millisieverts (16.5 rem). The plume of radioactive debris has been said to be equal to the contamination of 400 Hiroshima bombs. This is correct, but misleading. The main effect of the bomb was the direct radiation from the gamma blast. Compared to that, the contamination was only a minor addition. Furthermore the comparison to bomb fallout is very misleading, as an atomic bomb has a very different isotope signature to a power reactor. In bomb fall out plenty of the very shortlived isotopes are present while the activity in used power reactor fuel tends have a medium to long halflife. The time required for the dose rate to decline by a factor of 10 in an area covered with fallout from an atomic bomb which has detonated an hour ago is much shorter than the time required for the same reduction in dose rate due to chernobyl fallout (one hour after the reactor suffered the steam explosion).
[edit] Evacuation
Soviet authorities started evacuating people from the area around Chernobyl only on the second day after the disaster (within 36 hours). By May 1986, about a month later, all those living within a 30 km (18 mile) radius of the plant—about 116,000 people—had been relocated. This area is often referred to as the zone of alienation. However, radiation affected the area in a much wider scale than this 30 km radius.
According to reports from Soviet scientists, 28,000 km² (10,800 mi²) were contaminated by caesium-137 to levels greater than 185 kBq/m². Roughly 830,000 people lived in this area. About 10,500 km ² (4,000 mi²) were contaminated by caesium-137 to levels greater than 555 kBq/m². Of this total, roughly 7,000 km² (2,700 mi²) lie in Belarus, 2,000 km² (800 mi²) in the Russian Federation and 1,500 km² (580 mi²) in Ukraine. About 250,000 people lived in this area. These reported data were corroborated by the International Chernobyl Project.
[edit] Civilians
Some children in the contaminated areas were exposed to high radiation doses of up to 50 grays (Gy) because of an intake of radioactive iodine-131, a relatively short-lived isotope with a half-life of 8 days, from contaminated milk produced locally. Several studies have found that the incidence of thyroid cancer among children in Belarus, Ukraine and Russia has risen sharply. The IAEA notes "1800 documented cases of thyroid cancer in children who were between 0 and 14 years of age when the disaster occurred, which is far higher than normal", but fails to note the expected rate. The childhood thyroid cancers that have appeared are of a large and aggressive type but, if detected early, can be treated. Treatment entails surgery followed by iodine-131 therapy for any metastases. To date, such treatment appears to have been successful in the vast majority of cases.
Late in 1995, the World Health Organisation (WHO) linked nearly 700 cases of thyroid cancer among children and adolescents to the Chernobyl disaster, and among these some 10 deaths are attributed to radiation. However, the rapid increase in thyroid cancers detected suggests that some of it at least is an artifact of the screening process. Typical latency time of radiation-induced thyroid cancer is about 10 years, but the increase in childhood thyroid cancers in some regions was observed as early as 1987. Presumably either the increase is unrelated to the disaster or the mechanisms behind it are not well understood.
So far, no increase in leukemia is discernible, but this is expected to be evident in the next few years along with a greater, though not statistically discernible, incidence of other cancers. There has been no substantiated increase attributable to Chernobyl in congenital abnormalities, adverse pregnancy outcomes or any other radiation-induced disease in the general population, either in the contaminated areas or further afield.[citation needed]
One man had reported that after the meltdown, he woke up in the middle of the night, got out bed, and to his shock, the skin of his legs "fell off as if they were stockings". He then began to bleed rapidly where the skin had fallen off.
[edit] Long-term health effects
[edit] Science and politics: the problem of epidemiological studies
The issue of long-term effects of Chernobyl disaster on civilians is very controversial. The number of people whose lives were affected by the disaster is enormous. Over 300,000 people were resettled because of the disaster; millions lived and continue to live in the contaminated area. On the other hand, most of those affected received relatively low doses of radiation; there is little evidence of increased mortality, cancers or birth defects among them; and when such evidence is present, existence of a causal link to radioactive contamination is uncertain.
An increased incidence of thyroid cancer among children in areas of Belarus, Ukraine and Russia affected by the Chernobyl disaster has been firmly established as a result of screening programs and, in the case of Belarus, an established cancer registry. The findings of most epidemiological studies must be considered interim, say experts, as analysis of the health effects of the disaster is an ongoing process.
Epidemiological studies have been hampered in the former Soviet Union by a lack of funds, an infrastructure with little or no experience in chronic disease epidemiology, poor communication facilities and an immediate public health problem with many dimensions. Emphasis has been placed on screening rather than on well-designed epidemiological studies. International efforts to organize epidemiological studies have been slowed by some of the same factors, especially the lack of a suitable scientific infrastructure. Furthermore, the political nature of nuclear energy has heavily affected scientific studies. In Belarus, Yuri Bandazhevsky, a scientist who questioned the official estimates of Chernobyl's consequences and the relevancy of the official maximum limit of 1,000 Bq/kg, has been victim of political repression. He was imprisoned from 2001 to 2005, following his publication of reports critical of the official research being conducted into the Chernobyl incident. Almost all scientists knowledgeable in nuclear-related fields are funded by governmental agencies belonging to the military-industrial complex and the nuclear lobby (in France, to the Commissariat à l'Énergie Atomique (CEA - Atomic Energy Commissariat) and to the EDF electric power company). In France, the authorities thus claimed during years that the radioactive cloud had amazingly stopped at the Italian border. These claims were questioned by independent researchers such as the Commission de recherche et d'information indépendantes sur la radioactivité (CRIIRAD - Commission of Research and Independent Information on Radioactivity). Thus, public and democratic information about this catastrophe has led some to create independent research centers such as the CRIIRAD or the IPPNW, able to conduct scientific investigations without being tied to the nuclear lobby. As with AIDS,[citation needed] science has stopped being ideologically neutral and it has become obvious to most analysts[citation needed] that it carries on political objectives. The September 2005 IAEA report, made in cooperation with the Russian Federation, Belarus and Ukraine, is, according to its critics, an example of such a lack of public information.
The activities undertaken by Belarus and Ukraine in response to the disaster—remediation of the environment, evacuation and resettlement, development of uncontaminated food sources and food distribution channels, and public health measures—have overburdened the governments of those countries. International agencies and foreign governments have provided extensive logistic and humanitarian assistance. In addition, the work of the European Commission and World Health Organization in strengthening the epidemiological research infrastructure in Russia, Ukraine and Belarus is laying the basis for major advances in these countries' ability to carry out epidemiological studies of all kinds.
[edit] Cesium radioisotopes
- Further information: Fission products
Immediately after the disaster, the main health concern involved radioactive iodine, with a half-life of eight days. Today, there is concern about contamination of the soil with strontium-90 and caesium-137, which have half-lives of about 30 years. The highest levels of caesium-137 are found in the surface layers of the soil where they are absorbed by plants, insects and mushrooms, entering the local food supply. Some scientists fear that radioactivity will affect the local population for the several next generations. Note that cesium is not mobile in most soils because it binds to the clay minerals.[1][2][3] Recent tests (ca. 1997) have shown that caesium-137 levels in trees of the area are continuing to rise. There is some evidence that contamination is migrating into underground aquifers and closed bodies of water such as lakes and ponds (2001, Germenchuk). The main source of elimination is predicted to be natural decay of caesium-137 to stable barium-137, since runoff by rain and groundwater has been demonstrated to be negligible.
[edit] Food restrictions
Twenty years after the catastrophe, restriction orders remain in place in the production, transportation and consumption of food contaminated by Chernobyl fallout. In the UK, they remain in place on 374 farms covering 750 km² and 200,000 sheep. In parts of Sweden and Finland, restrictions are in place on stock animals, including reindeer, in natural and near-natural environments. "In certain regions of Germany, Austria, Italy, Sweden, Finland, Lithuania and Poland, wild game (including boar and deer), wild mushrooms, berries and carnivore fish from lakes reach levels of several thousand Bq per kg of caesium-137", while "in Germany, caesium-137 levels in wild boar muscle reached 40,000 Bq/kg. The average level is 6,800 Bq/kg, more than ten times the EU limit of 600 Bq/kg", according to the TORCH 2006 report. The European Commission has stated that "The restrictions on certain foodstuffs from certain Member States must therefore continue to be maintained for many years to come".[2]
As of 2006, sheep farmed in some areas of the UK are still subject to inspection which may lead to them being prohibited from entering the human food chain because of contamination arising from the accident:
"Some of this radioactivity, predominantly radiocaesium-137, was deposited on certain upland areas of the UK, where sheep-farming is the primary land-use. Due to the particular chemical and physical properties of the peaty soil types present in these upland areas, the radiocaesium is still able to pass easily from soil to grass and hence accumulate in sheep. A maximum limit of 1,000 becquerels per kilogramme (Bq/kg) of radiocaesium is applied to sheep meat affected by the accident to protect consumers. This limit was introduced in the UK in 1986, based on advice from the European Commission's Article 31 group of experts. Under power provided under the Food and Environment Protection Act 1985 (FEPA), Emergency Orders have been used since 1986 to impose restrictions on the movement and sale of sheep exceeding the limit in certain parts of Cumbria, North Wales, Scotland and Northern Ireland... When the Emergency Orders were introduced in 1986, the Restricted Areas were large, covering almost 9,000 farms, and over 4 million sheeps. Since 1986, the areas covered by restrictions have dramatically decreased and now cover 374 farms, or part farms, and around 200,000 sheep. This represents a reduction of over 95% since 1986, with only limited areas of Cumbria, South Western Scotland and North Wales, covered by restrictions.[3]
In Norway, the Sami people were affected by contaminated food (the reindeer had been contaminated by eating lichen, which are very sensitive to radioactivity).[4]
[edit] Effect on the natural world
According to reports from Soviet scientists at the First International Conference on the Biological and Radiological Aspects of the Chernobyl Accident (September 1990), fallout levels in the 10 km zone around the plant were as high as 4.81 GBq/m². The so-called "Red Forest" of pine trees [4][5], previously known as Worm Wood Forest and located immediately behind the reactor complex, lay within the 10 km zone and was killed off by heavy radioactive fallout. The forest is so named because in the days following the disaster the trees appeared to have a deep red hue as they died due to extremely heavy radioactive fallout. In the post-disaster cleanup operations, a majority of the 4 km² forest was bulldozed and buried. The site of the Red Forest remains one of the most contaminated areas in the world. However, it has proved to be an astonishingly fertile habitat for many endangered species. In marked contrast to the human cost, the evacuation of the area surrounding the plant has indeed created a lush and unique wildlife refuge. In the 1996 BBC Horizon documentary 'Inside Chernobyl's Sarcophagus', birds are seen flying in and out of large holes in the structure itself. It is unknown whether fallout contamination will have any long-term adverse effect on the flora and fauna of the region, as plants and animals have significantly different and varying radiologic tolerance compared with humans. Some birds are reported with stunted tail feathers (which interferes with breeding). However, it seems that the biodiversity around the massive radiation spill has increased due to the removal of human influence (see the first hand account of the wildlife preserve below). Storks, wolves, beavers, and eagles have been reported in the area. There are reports of mutations in some plants in the area, leading to unsubstantiated tales of a "forest of wonders" containing many strangely mutated plants. Specifically, some trees have weirdly twisted branches that do not reach for the sky.[5]
[edit] The September 2005 IAEA report and criticisms
In September 2005, a controversed report by the Chernobyl Forum, comprising a number of agencies including the International Atomic Energy Agency (IAEA), the World Health Organization (WHO), United Nations bodies and the Governments of Belarus, the Russian Federation and Ukraine, put the total predicted number of deaths due to the disaster at 4,000 (of which 2,200 deaths are expected to be in the ranks of 200,000 liquidators). This predicted death toll includes the 47 workers who died of acute radiation syndrome as a direct result of radiation from the disaster, nine children who died from thyroid cancer and an estimated 3,940 people who could die from cancer as a result of exposure to radiation. The report also stated that, apart from a 30 kilometre area around the site and a few restricted lakes and forests, radiation levels had returned to acceptable levels.[6][7]
The methodology of the Chernobyl Forum report has been disputed by Greenpeace, the International Physicians for Prevention of Nuclear Warfare (IPPNW), and Elisabeth Cardis of the International Agency for Research on Cancer [8]. The main criticism has been with regard to the restriction of the Forum's study to Belarus, Ukraine and Russia. Furthermore, it only studied the case of 200,000 people involved in the cleanup, and the 400,000 most directly affected by the released radiation. German Green Party Member of the European Parliament Rebecca Harms, commissioned a report on Chernobyl in 2006 (TORCH ,The Other Report on Chernobyl). The 2006 TORCH report claimed that:
"In terms of their surface areas, Belarus (22% of its land area) and Austria (13%) were most affected by higher levels of contamination. Other countries were seriously affected; for example, more than 5% of Ukraine, Finland and Sweden were contaminated to high levels (> 40,000 Bq/m2 caesium-137). More than 80% of Moldova, the European part of Turkey, Slovenia, Switzerland, Austria and the Slovak Republic were contaminated to lower levels (> 4,000 Bq/m2 caesium-137). And 44% of Germany and 34% of the UK were similarly affected." (See map of radioactive distribution of Caesium-137 in Europe)[2]
While the IAEA/WHO and UNSCEAR considered areas with exposure greater than 40,000 Bq/m2, the TORCH report also included areas contaminated with more than 4,000 Bq/m2 of Cs-137.
The TORCH 2006 report "estimated that more than half the iodine-131 from Chernobyl [which increases the risk of thyroid cancer] was deposited outside the former Soviet Union. Possible increases in thyroid cancer have been reported in the Czech Republic and the UK, but more research is needed to evaluate thyroid cancer incidences in Western Europe". It predicted about 30,000 to 60,000 excess cancer deaths, 7 to 15 Times greater than the figure of 4,000 in the IAEA press release; warned that predictions of excess cancer deaths strongly depend on the risk factor used; and predicted excess cases of thyroid cancer range between 18,000 and 66,000 in Belarus alone depending on the risk projection model.[9]
Another study claims possible heightened mortality in Sweden. [10].
Greenpeace quoted a 1998 WHO study, which counted 212 dead from only 72,000 liquidators. The environmental NGO estimated a total death toll of 93,000 but cite in their report that “The most recently published figures indicate that in Belarus, Russia and the Ukraine alone the disaster could have resulted in an estimated 200,000 additional deaths in the period between 1990 and 2004.” In its report, Greenpeace suggested there will be 270,000 cases of cancer alone attributable to Chernobyl fallout, and that 93,000 of these will probably be fatal (compare with the IAEA 2005 report which claimed that "99% of thyroid cancers wouldn't be lethal". Blake Lee-Harwood, campaigns director at Greenpeace, declared that cancer was likely to be the cause of less than half of the final fatalities; "intestinal problems, heart and circulation problems, respiratory problems, endocrine problems, and particularly effects on the immune system," are also concerns. Lee-Harwood alleged that the nuclear industry had a "vested interest in playing down Chernobyl because it's an embarrassment to them". Responding to these criticisms, the WHO spokesman Gregory Hartl explained that "the Greenpeace report is looking at all of Europe, whereas our report looks at only the most affected areas of the three most affected countries,".[11]
According to the Union Chernobyl, the main organization of liquidators, 10% of the 600,000 liquidators are now dead, and 165,000 disabled.[12]
According to a April 2006 report by the International Physicians for Prevention of Nuclear Warfare (IPPNW), entitled "Chernobyl's consequences on health", more than 10,000 people are today affected by thyroid cancer and 50,000 cases are expected. In Europe, the IPPNW claims that 10,000 deformities have been observed in newborns because of Chernobyl's radioactive discharge, with 5,000 deaths among newborn children. They also claim that several hundreds of thousands of the people who worked on the site after the disaster are now sick because of radiation, and tens of thousands are dead.[12]
[edit] Comparisons to other radioactivity releases
[edit] References
- ^ Chapter IV: Dose estimates, Nuclear Energy Agency, 2002
- ^ a b TORCH report executive summary. European Greens and UK scientists Ian Fairlie PhD and David Sumner (April 2006). Retrieved on April 21, 2006.
- ^ Post-Chernobyl Monitoring and Controls Survey Report. UK Food Standards Agency. Retrieved on April 19, 2006.
- ^ "Chernobyl fallout: internal doses to the Norwegian population and the effect of dietary advice", Strand P, Selnaes TD, Boe E, Harbitz O, Andersson-Sorlie A., National Institute of Radiation Hygiene, Osteras, Norway
- ^ "Wildlife defies Chernobyl radiation", BBC News, April 20, 2006.
- ^ IAEA Report. In Focus: Chernobyl. Retrieved on March 29, 2006.
- ^ For full coverage see the IAEA Focus Page<ref></ref> and joint IAEA/WHO/UNDP press release Chernobyl: The True Scale of the Accident, IAEA/WHO/UNDP, September 5, 2005 (pdf file)
- ^ "Special Report: Counting the dead", 'Nature', April 19, 2006. Retrieved on April 21, 2006.
- ^ TORCH report executive summary, op.cit., p.4
- ^ Chernobyl 'caused Sweden cancers', BBC News, November 20, 2004
- ^ "Greenpeace rejects Chernobyl toll", BBC News, April 18, 2006.
- ^ a b (French) "Selon un rapport indépendant, les chiffres de l'ONU sur les victimes de Tchernobyl ont été sous-estimés (According to an independent report, UN numbers on Chernobyl's victims has been underestimated)", Le Monde, April 7, 2006. and see also "'On n’a pas fini d’entendre parler de Tchernobyl', interview with Angelika Claussen, head of the German section of the IPPNW", Arte, April 13, 2006.
[edit] See also
- Yuri Bandazhevsky, a Belarussian scientist imprisoned from 2001 to 2005 after his publication of a report critical of the official investigation on the consequences of the Chernobyl disaster
- Nuclear and radiation accidents
- Chernobyl disaster
- Acute radiation syndrome
- Ionizing radiation
- Fission products, a more complete description of the radioactive byproducts of nuclear reactors
- Radiophobia
- Bellesrad
- Red Forest
- Three Mile Island accident
