Effects of the Chernobyl disaster

The Chernobyl disaster triggered the release of substantial amounts of radiation into the atmosphere in the form of both particulate and gaseous radioisotopes. It is the most significant unintentional release of radiation into the environment to date. It has been suggested that the radioactive contamination caused by the Chernobyl disaster greatly exceeded that of the atomic bombing of Hiroshima and Nagasaki in 1945. However, the work of the Scientific Committee on Problems of the Environment (SCOPE) suggests that the two events cannot be directly compared, with a number suggesting that one was x times larger than the other; the isotopes released at Chernobyl tended to be longer-lived than those released by a bomb detonation, producing radioactivity curves that vary in shape as well as size.

Dose to the general public within 30 km of the plant

The inhalation dose (internal dose) for the public (during the time between the accident occurring and their evacuation from the area) in what is now the 30 km evacuation zone around the plant has been estimated (based ground deposition of caesium-137) to be between 3 and 150 mSv {between a 1 in 6666.67 and a 1 in 133.33 chance of a fatal cancer, assuming the ICRP risk factor of a 5% of a fatal cancer per Sv of exposure} for adults (depending on the distance from the reactor and the day of evacuation) and for one year old children a dose estimate of between 10 and 700 mSv {between a 1 in 2000 and a 1 in 28.57 chance of fatal cancer} has been made. Thyroid doses for adults were between 20 and 1000 mSv, while for the one year old infants these were higher at 20 to 6000 mSv. For those who left at an early stage in the accident the internal dose due to inhalation was 8 to 13 times higher than the external dose due to gamma / beta emitters. For those who remained until later (day 10 or later) the inhalation dose was 50 to 70% higher than the dose due to external exposure. The majority of the dose was due to Iodine-131 (circa 40%), tellurium and rubidium isotopes (circa 20 to 30% for Rb and Te).

The ingestion doses in this same group of people have also been estimated using the caesium activity per unit of area, isotope ratios, average day of evacuation, intake rate of milk and green vegetables and what is known about the transfer of radioactivity via plants/animals to humans. For adults the dose has been estimated to be between 3 and 180 mSv while for the one year old infants a dose of between 20 and 1300 mSv has been estimated. Again the majority of the dose was due to Iodine-131 and the external dose was much smaller than the internal dose due to the radioactivity in the diet.

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 drifted not only over Russia, Belarus and Ukraine, but also over the European part of Turkey, Greece, Moldova, Romania, Bulgaria, Lithuania, Finland, Denmark, Norway, Sweden, Austria, Hungary, Czechoslovakia, Yugoslavia, Poland, Estonia, Switzerland, Germany, Italy, Ireland, France (including Corsica), Canada 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 kinds of food (mushrooms in particular) were prohibited in Italy because of radioactivity, the French authorities took no 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). 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 EBq (depending on source) of radioactive contamination released from the reactor. An additional 10 individuals have already died of cancer as a result of the disaster.

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 — 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.

Workers and liquidators

Soviet badge awarded to 600,000+ 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. Estimates of the number of "liquidators" 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 fallout plenty of the very short-lived isotopes are present while the activity in used power reactor fuel tends have a medium to long half-life. 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). A sevenfold increase in DNA mutations has been identified in liquidators' children conceived after the accident, when compared to their siblings conceived before. However, the effect diminishes sharply with time.

Evacuation

Map showing Caesium-137 contamination in the Chernobyl area as of 1996

Soviet authorities started evacuating people from the area around Chernobyl only on the second day after the disaster (after 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 cesium-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.

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 as 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.

Plant and animal health

An exhibit at the Ukrainian National Chernobyl Museum. Mutations in both humans and other animals may have increased as a result of the disaster.

A large swath of pine forest killed by acute radiation was named the Red Forest. The dead pines were bulldozed and buried. Livestock were removed during the human evacuations. Elsewhere in Europe, levels of radiation were examined in various natural foodstocks. In both Sweden and Finland, fish in deep freshwater lakes were banned for resale and landowners were advised not to consume certain types. Information regarding physical deformities in the plant and animal populations in the areas affected by radioactive fallout require capture and DNA testing of individuals to determine if abnormalities are the result of natural mutation, radiation poisoning, or exposure to other contaminants in the environment such as pesticides, industrial waste, or agricultural run-off.

Suggested long-range effects

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Graph of Down syndrome cases in Belarus

• Down syndrome (trisomy 21). In West Berlin, Germany, prevalence of Down syndrome (trisomy 21) peaked 9 months following the main fallout.[ 11, 12] Between 1980 and 1986, the birth prevalence of Down syndrome was quite stable (i.e., 1.35–1.59 per 1,000 live births [27–31 cases]). In 1987, 46 cases were diagnosed (prevalence = 2.11 per 1,000 live births). Most of the excess resulted from a cluster of 12 cases among children born in January 1987. The prevalence of Down syndrome in 1988 was 1.77, and in 1989, it reached pre-Chernobyl values. The authors noted that the isolated geographical position of West Berlin prior to reunification, the free genetic counseling, and complete coverage of the population through one central cytogenetic laboratory support completeness of case ascertainment; in addition, constant culture preparation and analysis protocols ensure a high quality of data.
• Chromosomal aberrations. Reports of structural chromosome aberrations in people exposed to fallout in Belarus and other parts of the former Soviet Union, Austria, and Germany argue against a simple dose-response relationship between degree of exposure and incidence of aberrations. These findings are relevant because a close relationship exists between chromosome changes and congenital malformations. Inasmuch as some types of aberrations are almost specific for ionizing radiation, researchers use aberrations to assess exposure dose. On the basis of current coefficients, however, one cannot assume that calculation of individual exposure doses resulting from fallout would not induce measurable rates of chromosome aberrations.
• Neural tube defects (NTDs) in Turkey. During the embryonic phase of fetal development, the neural tube differentiates into the brain and spinal cord (i.e., collectively forming the central nervous system). Chemical or physical interactions with this process can cause NTDs. Common features of this class of malformations are more or less extended fissures, often accompanied by consecutive dislocation of central nervous system (CNS) tissue. NTDs include spina bifida occulta and aperta, encephalocele, and—in the extreme case—anencephaly. The first evidence in support of a possible association between CNS malformations and fallout from Chernobyl was published by Akar et al.. in 1988. The Mustafakemalpasa State Hospital, Bursa region, covers a population of approximately 90,000. Investigators have documented the prevalence of malformations since 1983. The prevalence of NTDs was 1.7 to 9.2 per 1,000 births, but during the first 6 months of 1987 increased to 20 per 1,000 (12 cases). The excess was most pronounced for the subgroup of anencephalics, in which prevalence increased 5-fold (i.e., 10 per 1,000 [6 cases]). In the consecutive months that followed (i.e., July–December 1987), the prevalence decreased again (1.3 per 1,000 for all NTDs, 0.6 per 1,000 for anencephaly), and it reached pre-Chernobyl levels during the first half of 1988 (all NTDs: 0.6 per 1,000; anencephaly: 0.2 per 1,000). This initial report was supported by several similar findings in observational studies from different regions of Turkey.

Long-term health effects

Science and politics: the problem of epidemiological studies

An abandoned village near Prypiat, close to Chernobyl

The issue of long-term effects of the 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 may have affected scientific studies. In Belarus, Yury 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, was imprisoned from 2001 to 2005. Bandazhevsky and some human rights groups allege his imprisonment was a reprisal for his publication of reports critical of the official research being conducted into the Chernobyl incident.

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.

Caesium 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 next several generations. Note that caesium is not mobile in most soils because it binds to the clay minerals. 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.

25 years after the catastrophe

Twenty five 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 369 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 carnivorous 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".

As of 2009, 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 sheep. Since 1986, the areas covered by restrictions have dramatically decreased and now cover 369 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.

369 farms and 190,000 sheep are still affected, a reduction of 95% since 1986, when 9,700 farms and 4,225,000 sheep were under restriction across the United Kingdom.

In Norway, the Sami people were affected by contaminated food (the reindeer had been contaminated by eating lichen, which are very sensitive to radioactivity).

Effect on the natural world

File:Red forest.jpg

The major plume of radiation released by the Chernobyl Nuclear Accident was carried directly over what is now called the Red Forest. Radioactive particles settled on trees, killing areas of pine forest.

Earth Observing-1 image of the reactor and surrounding area in April of 2009.

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, 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 because of 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.

In recent years there have been many reports suggesting the zone may be a fertile habitat for wildlife. For example in the 1996 BBC Horizon documentary 'Inside Chernobyl's Sarcophagus', birds are seen flying in and out of large holes in the structure itself. Other casual observations suggest biodiversity around the massive radiation spill has increased due to the removal of human influence (see the first hand account of the wildlife preserve). Storks, wolves, beavers, and eagles have been reported in the area.

Barn swallows sampled between 1991 and 2006 both in the Chernobyl exclusion zone had more physical abnormalities than control sparrows sampled elsewhere in Europe. Abnormal barn swallows mated with lower frequency, causing the percentage of abnormal swallows to decrease over time. This demonstrated the selective pressure against the abnormalities was faster than the effects of radiation that created the abnormalities. "This was a big surprise to us," Dr. Mousseau said. "We had no idea of the impact."

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). 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. The Chernobyl area has not received very much biological study, although studies that have been done suggest that apparently healthy populations may be sink instead of source populations; in other words, that the apparently healthy populations are not contributing to the survival of species.

Using robots, researchers have actually retrieved samples of highly melanized black fungus from the walls of the reactor core itself. It has been shown that certain species of fungus, such as Cryptococcus neoformans and Cladosporium, can actually thrive in a radioactive environment, growing better than non-melanized variants, implying that they use melanin to harness the energy of ionizing radiation from the reactor.

The Chernobyl Forum report and criticisms

In September 2005, a comprehensive report was published 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. This report titled: "Chernobyl's legacy: Health, Environmental and Socio-Economic Impacts", authored by about 100 recognized experts from many countries, put the total predicted number of deaths due to the disaster around 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 4000 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. For full coverage see the IAEA Focus Page.

The methodology of the Chernobyl Forum report has been disputed by some advocacy organizations opposed to nuclear energy, such as Greenpeace and the International Physicians for Prevention of Nuclear Warfare (IPPNW), as well as some individuals such as Elisabeth Cardis of the International Agency for Research on Cancer, Dr. Michel Fernex, retired medical doctor from the WHO and campaigner Dr. Christopher Busby (Green Audit, LLRC). 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)

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.

Another study claims possible heightened mortality in Sweden.

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,". Though it should be noted that Greenpeace is decidedly anti-nuclear power in its stance.

According to the Union Chernobyl, the main organization of liquidators, 10% of the 600,000 liquidators are now dead, and 165,000 disabled.

According to a April 2006 report by the International Physicians for Prevention of Nuclear Warfare (IPPNW), entitled "Health Effects of Chernobyl - 20 years after the reactor catastrophe", 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.

Controversy over human health effects

The majority of premature deaths caused by Chernobyl are expected to be the result of cancers and other diseases induced by radiation in the decades after the event. This will be the result of a large population (some studies have considered the entire population of Europe) exposed to relatively low doses of radiation increasing the risk of cancer across that population. It will be impossible to attribute specific deaths to Chernobyl, and many estimates indicate that the rate of excess deaths will be so small as to be statistically undetectable, even if the ultimate number of extra premature deaths is large. Furthermore, interpretations of the current health state of exposed populations vary. Therefore, estimates of the ultimate human impact of the disaster have relied on numerical models of the effects of radiation on health. Furthermore, the effects of low-level radiation on human health are not well understood, and so the models used, notably the linear no threshold model, are open to question.

Given these factors, several different studies of Chernobyl's health effects have come up with substantially different conclusions and are the subject of considerable scientific and political controversy. The following section presents some of the major studies on this topic.

New York Academy of Sciences publication

Chernobyl: Consequences of the Catastrophe for People and the Environment is an English translation of the 2007 Russian publication Chernobyl. It was published online in 2009 by the New York Academy of Sciences in their Annals of the New York Academy of Sciences. It presents an analysis of scientific literature and concludes that medical records between 1986, the year of the accident, and 2004 reflect 985,000 deaths as a result of the radioactivity released. The authors suggest that most of the deaths were in Russia, Belarus and Ukraine, but others were spread through the many other countries the radiation from Chernobyl struck. The literature analysis draws on over 1,000 published titles and over 5,000 internet and printed publications discussing the consequences of the Chernobyl disaster. The authors contend that those publications and papers were written by leading Eastern European authorities and have largely been downplayed or ignored by the IAEA and UNSCEAR. Author Alexy V. Yablokov was also one of the general editors on the Greenpeace commissioned report also criticizing the Chernobyl Forum finds published one year prior to the Russian language version of this report.

The Chernobyl Forum report

In September 2005, a draft summary report by the Chernobyl Forum, comprising a number of UN agencies including the International Atomic Energy Agency (IAEA), the World Health Organization (WHO), the United Nations Development Programme (UNDP), other UN bodies and the Governments of Belarus, the Russian Federation and Ukraine, put the total predicted number of deaths due to the accident at 4000. This death toll predicted by the WHO included the 47 workers who died of acute radiation syndrome as a direct result of radiation from the disaster and nine children who died from thyroid cancer, in the estimated 4000 excess cancer deaths expected among the 600,000 with the highest levels of exposure. The full version of the WHO health effects report adopted by the UN, published in April 2006, included the prediction of 5000 additional fatalities from significantly contaminated areas in Belarus, Russia and Ukraine and predicted that, in total, 9000 will die from cancer among the 6.9 million most-exposed Soviet citizens. This report is not free of controversy, and has been accused of trying to minimize the consequences of the accident.

The TORCH report

Main article: TORCH report

In 2006 German Green Party Member of the European Parliament Rebecca Harms commissioned two UK scientists for an alternate report (TORCH, The Other Report on CHernobyl) in response to the UN report. The report included areas not covered by the Chernobyl forum report, and also lower radiation doses. It predicted about 30,000 to 60,000 excess cancer deaths and warned that predictions of excess cancer deaths strongly depend on the risk factor used, and urged more research stating that large uncertainties made it difficult to properly assess the full scale of the disaster.

Greenpeace

Demonstration on Chernobyl day near WHO in Geneva

Greenpeace claimed contradictions in the Chernobyl Forum reports, quoting a 1998 WHO study referenced in the 2005 report, which projected 212 dead from 72,000 liquidators. In its report, Greenpeace suggested there will be 270,000 cases of cancer attributable to Chernobyl fallout, and that 93,000 of these will probably be fatal, but state in their report that "The most recently published figures indicate that in Belarus, Russia and Ukraine alone the accident could have resulted in an estimated 200,000 additional deaths in the period between 1990 and 2004." Blake Lee-Harwood, campaigns director at Greenpeace, believes that cancer was likely to be the cause of less than half of the final fatalities and that "intestinal problems, heart and circulation problems, respiratory problems, endocrine problems, and particularly effects on the immune system," will also cause fatalities. However, concern has been expressed about the methods used in compiling the Greenpeace report.

The April 2006 IPPNW report

According to an April 2006 report by the German affiliate of the International Physicians for Prevention of Nuclear Warfare (IPPNW), entitled "Health Effects of Chernobyl", more than 10,000 people are today affected by thyroid cancer and 50,000 cases are expected. The report projected tens of thousands dead among the liquidators. In Europe, it alleges that 10,000 deformities have been observed in newborns because of Chernobyl's radioactive discharge, with 5000 deaths among newborn children. They also claimed that several hundreds of thousands of the people who worked on the site after the accident are now sick because of radiation, and tens of thousands are dead.

The 2011 UNSCEAR report

The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) produced a report [1] drastically different to many appreciations of the effects previously produced. The report concludes that 134 staff and emergency workers suffered acute radiation syndrome and of those 28 died of the condition. Many of the survivors suffered skin conditions and radiation induced cataracts, and 19 have since died, but not usually of conditions associated with radiation exposure. Of the several hundred thousand liquidators, apart from indications of increased leukaemia risk, there is no other evidence of health effects. In the general public, the only effect with 'persuasive evidence' is a substantial fraction of the 6,000 cases of thyroid cancer in adolescents observed in the affacted areas. By 2005, 15 cases had proved fatal.

The total deaths reliably attributable to the radiation produced by the accident therefore stands at 62 by the estimate of UNSCEAR.

The report concludes that 'the vast majority of the population need not live in fear of serious health consequences from the Chernobyl accident'.

Other studies and claims

• The Ukrainian Health Minister claimed in 2006 that more than 2.4 million Ukrainians, including 428,000 children, suffer from health problems related to the catastrophe. Psychological after-effects, as the 2006 UN report pointed out, have also had adverse effects on internally displaced persons.
• In a recently published study scientists from Forschungszentrum Jülich, Germany, published the “Korma-Report” with data of radiological long-term measurements that were performed between 1998 and 2007 in a region in Belarus that was affected by the Chernobyl accident. The internal radiation exposure of the inhabitants in a village in Korma County/Belarus caused by the existing radioactive contamination has experienced a significant decrease from a very high level. The external exposure, however, reveals a different picture. Although an overall decrease was observed, the organic constituents of the soil show an increase in contamination. This increase was not observed in soils from cultivated land or gardens. According to the Korma Report the internal dose will decrease to less than 0.2 mSv/a in 2011 and to below 0.1 mSv/a in 2020. Despite this, the cumulative dose will remain significantly higher than “normal” values due to external exposure. Resettlement may even be possible in former prohibited areas provided that people comply with appropriate dietary rules.
• Another study alleged heightened mortality in Sweden.
• According to the Union Chernobyl, the main organization of liquidators, 10% of the 600,000 liquidators are now dead, and 165,000 disabled.
• One study reports increased levels of birth defects in Germany and Finland in the wake of the accident.
• A change in the human sex ratio at birth in several European countries has been linked to Chernobyl fallout.

• In the Czech Republic, thyroid cancer has increased significantly after Chernobyl.

• A report from the European Committee on Radiation Risk (a body sponsored by the European Green Party) claims that the World Health Organization, together with most other international and national health bodies, has marginalized or ignored, perhaps purposely, the terrible consequences of the Chernobyl fallout to protect the vested interests of the nuclear industry.
• The Abstract of the April 2006 International Agency for Research on Cancer report Estimates of the cancer burden in Europe from radioactive fallout from the Chernobyl accident stated "It is unlikely that the cancer burden from the largest radiological accident to date could be detected by monitoring national cancer statistics. Indeed, results of analyses of time trends in cancer incidence and mortality in Europe do not, at present, indicate any increase in cancer rates – other than of thyroid cancer in the most contaminated regions – that can be clearly attributed to radiation from the Chernobyl accident." However, while undetectable, they estimate, based on the linear no threshold model of cancer effects, that 16,000 excess cancer deaths could be expected from the effects of the Chernobyl accident up to 2065. Their estimates have very wide 95% confidence intervals from 6,700 deaths to 38,000.

• The application of the linear no threshold model to predict deaths from low levels of exposure to radiation was disputed in a BBC (British Broadcasting Corporation) Horizon documentary, broadcast on July 13, 2006. It offered statistical evidence to suggest that there is an exposure threshold of about 200 millisieverts, below which there is no increase in radiation-induced disease. Indeed it went further, reporting research from Professor Ron Chesser of Texas Tech University, which suggests that low exposures to radiation can have a protective effect. The program interviewed scientists who believe that the increase in thyroid cancer in the immediate area of the explosion had been over-recorded, and predicted that the estimates for widespread deaths in the long term would be proved wrong. It noted the view of the World Health Organization scientist Dr Mike Rapacholi that, while most cancers can take decades to manifest, leukemia manifests within a decade or so: none of the previously expected peak of leukemia deaths has been found, and none is now expected. Identifying the need to balance the "fear response" in the public's reaction to radiation, the program quoted Dr Peter Boyle, director of the IARC: "Tobacco smoking will cause several thousand times more cancers in the [European] population."
• Professor Wade Allison of Oxford University (a lecturer in medical physics and particle physics) gave a talk on ionising radiation Nov 24, 2006 in which he gave an approximate figure of 81 cancer deaths from Chernobyl (excluding 28 cases from acute radiation exposure and the thyroid cancer deaths which he regards as "avoidable"). In a closely reasoned argument using statistics from therapeutic radiation, exposure to elevated natural radiation (the presence of radon gas in homes) and the diseases of Hiroshima and Nagasaki survivors he demonstrated that the linear no-threshold model should not be applied to low-level exposure in humans, as it ignores the well-known natural repair mechanisms of the body.
• A photographic essay by photojournalist Paul Fusco documents the legacy of the meltdown on local children

French legal action

Since March 2001, 400 lawsuits have been filed in France against "X" (the French equivalent of John Doe, an unknown person or company) by the French Association of Thyroid-affected People, including 200 in April 2006. These persons are affected by thyroid cancer or goitres, and have filed lawsuits alleging that the French government, at the time led by Prime Minister Jacques Chirac, had not adequately informed the population of the risks linked to the Chernobyl radioactive fallout. The complaint contrasts the health protection measures put in place in nearby countries (warning against consumption of green vegetables or milk by children and pregnant women) with the relatively high contamination suffered by the east of France and Corsica. Although the 2006 study by the French Institute of Radioprotection and Nuclear Safety said that no clear link could be found between Chernobyl and the increase of thyroid cancers in France, it also stated that papillary thyroid cancer had tripled in the following years.

Comparisons to other radioactivity releases

Main article: Chernobyl compared to other radioactivity releases

See also

• Bellesrad
• Chernobyl Children's Project (UK)
• Chernobyl disaster
• Chernobyl compared to other radioactivity releases
• Chernobyl Heart
• Chernobyl in the popular consciousness
• Chernobyl Shelter Fund
• Chernobyl Children's Project International
• Deaths due to the Chernobyl disaster
• Acute radiation syndrome
• Ionizing radiation
• Fission products, a more complete description of the radioactive byproducts of nuclear reactors
• Liquidator (Chernobyl)
• List of Chernobyl-related articles
• Nuclear and radiation accidents
• Nuclear power debate
• Radiophobia
• Red Forest
• Three Mile Island accident
• Three Mile Island accident health effects
• Yury Bandazhevsky, a Belarusian scientist imprisoned from 2001 to 2005 after his publication of a report critical of the official investigation on the consequences of the Chernobyl disaster

External links

• Animated map of radioactive cloud, French IRSN (official Institut de Radioprotection et de Sûreté Nucléaire — Institute of Radioprotection and Nuclear Safety) "Les leçons de Tchernobyl". IRSN. Retrieved 2009-12-07.
• Chernobyl animals worse affected than thought: study