Unconscious Exposure to Radiation

Abstract

When we consider the risk of radiation caused by the Fukushima Daiichi Nuclear Plant accident, we may feel the situation to be much like the formation of rain spots on a car. The dirty spots are difficult to tolerate by the owner of a brand-new car but can be accepted by a used car owner who does not clean his or her car frequently. In the course of collecting information to prepare a webpage concerning radiation risk on the Japanese Environmental Mutagen Society (JEMS) homepage following the Fukushima accident, I have learned that we have already unconsciously been exposed to an unexpected level of radiation. Therefore, our body is not like that brand-new car affected by rain spots or, in this case, radioactive contamination. We are internally exposed to ⁴⁰K radiation through the foods we eat on a daily basis, and we have already been exposed to the 1,000-10,000 times higher background of the nuclear fallout that occurred during the 1960s because of world-wide nuclear bomb experiments. It is important to know these facts to consider the excess risk derived from the Fukushima accident and thereby learn to be more cautious. Obtaining a proper answer scientifically about the health effects of low-level radiation exposure is very difficult when using available data on radiation biology. Increasing risk awareness and communication is also important together with proving the real risk of low-level radiation. Radiation risk should be considered in a relative manner by comparing it with other confounding factors, which together can be treated as a total risk. The increased risk posed by radiation exposure can be traded-off by reducing other risk factors affecting our lifestyle. The most important task for us is to transfer available scientific knowledge to the public such that the information is more understandable to help people make their own decisions on how to face radiation risk.