Estimation of Dietary Intake of Radionuclides and Effectiveness of Regulation after the Fukushima Accident and in Virtual Nuclear Power Plant Accident Scenarios

Abstract

Evaluation of radiation exposure from diet is necessary under the assumption of a virtual accident as a part of emergency preparedness. Here, we developed a model with complete consideration of the regional food trade using deposition data simulated by a transport model, and estimated the dietary intake of radionuclides and the effectiveness of regulation (e.g., restrictions on the distribution of foods) after the Fukushima accident and in virtual accident scenarios. We also evaluated the dilution factors (i.e., ratios of contaminated foods to consumed foods) and cost-effectiveness of regulation as basic information for setting regulatory values. The doses estimated under actual emission conditions were generally consistent with those observed in food-duplicate and market-basket surveys within a factor of three. Regulation of restricted food distribution resulted in reductions in the doses of 54–65% in the nearest large city to the nuclear power plant. The dilution factors under actual emission conditions were 4.4% for radioiodine and 2.7% for radiocesium, which are ~20 times lower than those used in the Japanese provisional regulation values after the Fukushima accident. Strict regulation worsened the cost-effectiveness for both radionuclides. This study highlights the significance and utility of the developed model for a risk analysis of emergency preparedness and regulation.

Public Health Preparedness for and Response to Nuclear Disasters: An Editorial

“…Two studies, Uchiyama et al and Murakami et al, added evidence on internal radiation dose assessment for the inhalation of radio-iodine and/or ingestion of radio-cesium. The authors emphasized that by taking into account adequate exposure scenarios, internal dose assessment based on environmental monitoring or survey data could yield good reliability, equivalent to the methods using direct measurement, such as anthropogammametry [ 11 , 12 ]. Murakami et al also proposed a greater use of their assessment approaches and methodologies in a range of food regulatory measures for a future nuclear disaster.…”