The greatest accident in the history of nuclear power occurred on April 26th, 1986, at Chernobyl in the former Soviet Union. A massive explosion released a large inventory of radioactivity to the atmosphere to be carried widely over Europe and deposited as fallout.
Nearly 20 years later an international team of more than 100 scientists has issued a report entitled Chernobyl's Legacy: Health, Environmental and Socio-Economic Impacts (September, 2005). The group, called The Chernobyl Forum, is made up of eight specialised UN agencies including the International Atomic Energy Agency, World Health Organisation, UN Development Programme, Food and Agriculture Organisation, UN Environment Programme, UN Office for Coordination of Humanitarian Affairs, UN Scientific Committee on Effects of Atomic Radiation, and the World Bank. The governments of Belarus, Russian Federation and Ukraine, the three most affected countries, were also involved.
The report concludes that although 4,000 people could eventually die as a result of exposure to radiation from the Chernobyl accident, as of mid-2005 fewer than 60 deaths can be directly attributed to radiation from the incident. Almost all of these deaths were among highly exposed rescue workers most of whom died shortly after the accident, although others died as late as 2004.
The chairman of the Chernobyl Forum, Dr Burton Bennett, said: "This latest research can help to settle the outstanding questions about how much death, disease and economic fallout really resulted from the Chernobyl accident. This was a very serious accident, especially for the thousands of workers exposed in the early days who received very high doses of radiation and for the thousands more stricken with thyroid cancer. By and large however, we have not found profound negative health impacts to the rest of the population in surrounding areas nor have we found widespread contamination that would continue to pose a substantial threat to human health, with a few exceptional, restricted areas."
About 1,000 on-site reactor staff and emergency workers were exposed to high levels of radiation on the day of the accident and more than 200,000 emergency and recovery operation workers were exposed during 1986-1987. Some 2,200 radiation-caused deaths can be expected over the lifetime of these people. This figure rises to 4,000 when residents of the most contaminated local areas (270,000) and evacuees (116,000) are taken into account. These figures would qualify Chernobyl as a serious accident, but not a disaster.
Fifty-six deaths have been directly attributed to the accident to-date. This figure comprises 47 emergency workers most of whom died early on from acute radiation syndrome (ie, died within months from massive exposure to radiation) and nine deaths among young children who developed thyroid cancer after drinking milk contaminated with radioactive iodine.
These figures are considerably less than popular worldwide and local perception of the impact of the Chernobyl accident would suggest. Confusion over the impact of the accident arises because thousands of people in the affected areas have since died of natural causes unrelated to radiation, but a widespread expectation of ill-health and a tendency to attribute all ill-health problems to radiation have led local residents, and many observers from afar, to assume that Chernobyl-related fatalities were much higher than they were in reality.
The greatest harm was inflicted on emergency workers, many of whom displayed great heroism. In the wider region, residents who ate food contaminated with radioactive iodine in the days following the accident received relatively high doses to the thyroid gland - iodine in food concentrates in the thyroid. Children who drank milk from cows fed on contaminated grass were particularly affected and there was a high incidence of thyroid cancer in children - about 4,000 cases. Ninety-nine percent of those cases were treated successfully, but nine children died.
Most people living in contaminated areas received relatively low whole body doses, comparable to natural background levels of radiation. No evidence of decreased fertility among the affected population has been found. There is no evidence of effects on number of stillbirths, delivery complications or overall health of babies.
A modest increase in reported congenital malformations in both contaminated and uncontaminated areas of Belarus appears to be related to better reporting and not to radiation.
Ecosystems affected by Chernobyl fallout have been studied for the past 20 years. More than 200,000 square kilometres of Europe were contaminated. The extent of contamination was patchy, depending on whether it was raining when contaminated air masses passed overhead. The recent report shows that, except for the still closed, highly contaminated 30km area around the reactor, and some closed lakes and restricted forests, radiation levels have mostly returned to acceptable levels.
The report concludes that the largest public health problem resulting from the accident is "the mental health impact". Residents in the region, who were victims of a tragedy they poorly understand, continue to suffer grave anxiety and this has prevented them from restarting their lives. This "paralysing fatalism" has led to an increase in drug and alcohol use, unprotected sex and unemployment. The report recommends that the first priority should be to encourage these people to normalise their lives by providing them with realistic information about the minimal risks they face.
However the report acknowledges that about 200,000 people continue to be severely affected by the disaster in a very real way. These include poor rural dwellers who live in the few severely contaminated areas, people with thyroid cancer and people who were resettled after the accident but who never found a home or employment in their new communities. These people "need substantial material assistance to rebuild their lives".