INTERNATIONAL PROGRAM ON THE HEALTH-EFFECTS OF THE CHERNOBYL ACCIDENT

The International Program on the Health Effects of the Chernobyl Accid ent (IPHECA) was established by the World Health Organization (WHO) in 1991. Currently, the technical part of IPHECA consists of five projec ts addressing the following areas of priority health problems or needs : thyroid, hematology, brain damage in utero, epidemiological registry and oral health, Important findings are: 1) a significant increase of thyroid cancer in children in Belarus and Ukraine since 1989, and in Russia since 1992 though not so pronounced. A relationship between det ected thyroid cancers and radiation exposure is yet to be established, 2) no increase yet in the incidence of hemoblastoses in the three Sta tes, 3) no relationship established between mental retardation and rad iation exposure in utero in 4,500 children investigated. The importanc e of dosimetry and biological indicators of radiation damage has been recognized by IPHECA. Several methods of biological and physical dosim etry are being employed using instrumentation provided by IPHECA. Some preliminary results indicate: 1) unstable aberrations can indicate an integral exposure but it is heavily biased to recent exposures, 2) wh en comparing healthy persons and patients with hematological diseases in contaminated areas, there is a higher ratio of total aberrations co mpared to their background and that the level of stable is lower than unstable aberrations, and 3) by applying electron spin resonance (ESR) it has been shown that the individual distribution of doses approache s a log-normal one, especially for adults, and that a peak shift towar ds higher doses is noticeable for children.