Reducing radiation exposure using commonly available objects.

Objectives: One and a half years have passed since the Fukushima Daiichi nuclear power plant disaster. The environmental radiation dose rate was not critical, but an existing exposure situation has been identified in a large part of Fukushima Prefecture. Although people continue to live and work in the contaminated area, they are not provided with sufficient information to reduce their exposure to radiation by themselves. In this study, we attempt to evaluate the efficiency of radiation shielding by using everyday items widely available to people.

Methods: NaI scintillation and Geiger-Müller survey meters were used to measure the radiation dose of (1) contaminated soil and (2) soil covered with commonly available items.

Results: In the soil at a depth of 10 cm from the surface, the radiation dose rate decreased from 3.36 to 0.65 μSv/h, and the count rate decreased from 3,120 to 352 cpm. Both the radiation dose rate and count rate reduced when the soil was covered with everyday items, such as a magazine more than 20 mm thick, a polystyrene foam board, and a wooden board of the same thickness.

Conclusions: To protect residents from unnecessary radiation exposure in the existing exposure situation, covering contaminated soil with a wooden board or a magazine, either of them 20 mm thick, is useful to reduce the radiation dose.