BEIR VII or seventh Biological Effects of Ionizing Radiation report on “Health Risks from Exposure to Low Levels of Ionizing Radiation
Washington, DC July 30, 2005 | The National Academies of Science released an over 700-page report yesterday on the risks from ionizing radiation. The BEIR VII or seventh Biological Effects of Ionizing Radiation report on “Health Risks from Exposure to Low Levels of Ionizing Radiation” reconfirmed the previous knowledge that there is no safe level of exposure to radiation—that even very low doses can cause cancer. Risks from low dose radiation are equal or greater than previously thought. The committee reviewed some additional ways that radiation causes damage to cells.
Among the reports conclusions are:
There is no safe level or threshold of ionizing radiation exposure.
Even exposure to background radiation causes some cancers. Additional exposures cause additional risks.
Radiation causes other health effects such as heart disease and stroke, and further study is needed to predict the doses that result in these non-cancer health effects.
It is possible that children born to parents that have been exposed to radiation could be affected by those exposures.
The “bystander effect” is an additional, newly recognized method by which radiation injures cells that were not directly hit but are in the vicinity of those that were. “Genomic instability” can be caused by exposure to low doses of radiation and according to the report “might contribute significantly to radiation cancer risk.” These new mechanisms for radiation damage were not included in the risk estimates reported by the BEIR VII report, but were recommended for further study.
The Linear-No-Threshold model (LNT) for predicting health effects from radiation (dose-response) is retained, meaning that every exposure causes some risk and that risks are generally proportional to dose. The Dose and Dose-Rate Effectiveness Factor or DDREF which had been suggested in the 1990 BEIR V report to be applied at low doses, has been reduced from 2 to 1.5. That means the projected number of health effects at low doses are greater than previously thought...