The evidence of dose response effects after radiation effects in embryos and fetuses exposed to Chernobyl fallout

Full text: Questions about the safety of applying the current radiation risk model of the ICRP to the internal exposures of unborn human life rose after observations of excess infant leukemia (0-1 years age-group) following contamination by low doses from the Chernobyl accidents 1986 in five different countries (Busby, 2009). Current legal frameworks for radiation exposure limits based on the risk models of ICRP present a safe threshold dose range for up to 100 mSv for radiogenic effects from in utero exposure. Data from cumulative absorbed doses to the fetus from Belarus. Germany, Greece, Scotland and Wales, however, suggest that in addition to increased risks for leukemias also significant effects on fetal loss, malformations and infant death as well as Down's syndrome indicate that the basic assumptions for the models are incomplete, referring only to experiences of A-bomb-survivors (Busby, C., Lengfelder, E., Pflugbeil, S., Schmitz-Feuerhake, 2009). Epidemiological data on birth cohorts from Greece, Germany and the United Kingdom before and after 1986 show significantly increased leukaemia risks for those born during the defined peak exposure at low doses compared with effect from higher doses which suggests different effects on the induction of DNA-repair. This may explain the inconsistencies of the results on reproductive effects which led to criticism and denial of Chernobyl findings in this realm. The possibility that physical dosimetric models have underestimated the effective exposure as an explanation is supported by biological dosimetry carried out in the contaminated regions. Since cohorts had been chosen specifically on the basis of exposure to internal radionuclides, the assumptions about effects after in utero exposure are based on significant errors (up to 160-fold according to Busby, 2009) in the conventional modelling for such internal fetal exposures and need to be revised. (authors)