Low Levels of Radiation Pose Threat to Health
Ionizing radiation, such as from x- and gamma rays, is both naturally occurring and man-made. Some of its sources include radon gas, nuclear fallout and medical x-ray scans. The BEIR VII report addresses the effects of a low dose or minimal exposure to ionizing radiation.
BEIR VII updates and revises the BEIR V report, which was released in 1990. It incorporates new data from cellular level studies and population monitoring. The BEIR committee continued to reject the theory supported by many in the nuclear industry that low doses of radiation are insignificant and possibly beneficial. The latest BEIR report concludes that a linear no threshold model is the most appropriate for risk assessment. This model assumes that risk increases along with exposure and asserts that any amount of radiation exposure, no matter how small, produces an increased risk of cancer.
The BEIR VII report found the risk of cancer to be greater for women and children. Among women, the cancer risk for solid tumors, such as in the lung and breast, is almost double that of men. The cancer mortality risk in women is more than 35 percent higher. Among children, the risk is greater than for adults and increases for younger children. For example, female infants have double the risk of their male counterparts.
While the report found no direct evidence that exposed parents could transmit mutations to their children, it did find evidence of such mutations among animals. The report concludes that there is no reason to believe humans would be immune. It also linked non-cancer effects, such as heart disease and stroke, to high dose exposure, although more research is needed before a connection can be made to low dose exposure.
The findings of the BEIR VII report differ from those previously used for determining the federal regulations for radiation exposure. It shows the average risk to the population to be 10 to 15 percent greater than the reference value now used.
Dr. Arjun Makhijani, president of the Institute for Energy and Environmental Research, corresponded with the BEIR committee during the review process. In response to the release, Dr. Makhijani said, "The BEIR VII report has done the public a great service by putting the [official approval] of the [National Academies of Sciences] on solid research that has long indicated much greater risks for women and children. Now it is up to the [EPA] to change the framework of regulation from averages of men and women to those who are most at risk."
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