26 April 2006 marks the 20th anniversary of the Chernobyl accident. On this occasion, the World Health Organization (WHO), within the UN Chernobyl Forum initiative, convened an Expert Group to evaluate the health impacts of Chernobyl. This paper summarises the findings relating to cancer. A dramatic increase in the incidence of thyroid cancer has been observed among those exposed to radioactive iodines in childhood and adolescence in the most contaminated territories. Iodine deficiency may have increased the risk of developing thyroid cancer following exposure to radioactive iodines, while prolonged stable iodine supplementation in the years after exposure may reduce this risk. Although increases in rates of other cancers have been reported, much of these increases appear to be due to other factors, including improvements in registration, reporting and diagnosis. Studies are few, however, and have methodological limitations. Further, because most radiation-related solid cancers continue to occur decades after exposure and because only 20 years have passed since the accident, it is too early to evaluate the full radiological impact of the accident. Apart from the large increase in thyroid cancer incidence in young people, there are at present no clearly demonstrated radiation-related increases in cancer risk. This should not, however, be interpreted to mean that no increase has in fact occurred: based on the experience of other populations exposed to ionising radiation, a small increase in the relative risk of cancer is expected, even at the low to moderate doses received. Although it is expected that epidemiological studies will have difficulty identifying such a risk, it may nevertheless translate into a substantial number of radiation-related cancer cases in the future, given the very large number of individuals exposed.

Several United Nations organizations sought to dispel the uncertainties and controversy that still exist concerning the effects of the Chernobyl accident. A Chernobyl Forum of international expertise was established to reach consensus on the environmental consequences and health effects attributable to radiation exposure arising from the accident. This review is a synopsis of the subgroup that examined the radiological effects to nonhuman biota within the 30-km Exclusion Zone. The response of biota to Chernobyl irradiation was a complex interaction among radiation dose, dose rate, temporal and spatial variation, varying radiation sensitivities of the different taxons, and indirect effects from other events. The radiation-induced effects to plants and animals within the 30-km Exclusion Zone around Chernobyl can be framed in three broad time periods relative to the accident: an intense exposure period during the first 30 d following the accident of 26 April 1986; a second phase that extended through the first year of exposure during which time the short-lived radionuclides decayed and longer-lived radionuclides were transported to different components of the environment by physical, chemical and biological processes; and the third and continuing long-term phase of chronic exposure with dose rates<1% of the initial values. The doses accumulated, and the observed effects on plants, soil invertebrates, terrestrial vertebrates and fish are summarized for each time period. Physiological and genetic effects on biota, as well as the indirect effects on wildlife of removing humans from the Chernobyl area, are placed in context of what was known about radioecological effects prior to the accident.

An enzyme catalyzing the synthesis of adenosine diphosphate (ADP) glucose from adenosine triphosphate (ATP) and -glucose 1-phosphate has been partially purified from Escherichia coli B. It was found that ADP glucose pyrophosphorylase activity could be stimulated by a number of glycolytic intermediates.

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