Total Diet Study to Assess Radioactive Cs and 40K Levels in the Japanese Population before and after the Fukushima Daiichi Nuclear Power Plant Accident.

Hiroshi Terada,Ikuyo Iijima,Hideo Sugiyama,Kimio Isomura,Sadaaki Miyake

doi:10.3390/ijerph17218131

Abstract

We conducted a total diet study (TDS) of 137Cs, 134Cs, and 40K to assess their average dietary exposure levels in a Japanese adult population before and after the Fukushima Daiichi nuclear power plant (FDNPP) accident. Nineteen market baskets were evaluated in 2006–2011. In each basket, a TDS sample comprising tap water and 160–170 food items, which were combined into 13 groups, were collected for analysis by gamma-ray spectrometry. From 2006 to 2010, the 137Cs activity concentration in the “fish and shellfish” group was 0.099 Bq/kg, representing the highest value obtained, whereas the total committed effective dose (CED) of radiocesium isotopes (137Cs + 134Cs) was 0.69 μSv. In 2011, “milk and dairy products” from Sendai City had a Cs activity concentration of 12 Bq/kg, representing the highest values among all food groups studied. However, the annual CED of radioactive Cs in Fukushima City was 17 μSv after the FDNPP accident, which is 60-fold lower than the maximum permissible dose of 1 mSv/year. The mean CED obtained for 40K was 180 μSv, which is comparable to the global average. Our results reveal the average dietary exposure of 137Cs, 134Cs, and 40K, which can aid in estimating the radiological safety of foods.

Highlights

To ensure food safety, it is essential to assess the exposure levels to toxic substances in food.Currently, there are three approaches for estimating the dietary intake of such substances: total diet study (TDS), duplicate portion study (DPS), and selective study of individual foodstuffs
Cesium-137 was the only anthropogenic radionuclide observed in these samples, as 134 Cs, which was released from the Chernobyl disaster, was not detected at all
The present study provides an estimate of the average dietary exposure of 137 Cs, 134 Cs, and 40 K for adults in Japan

Summary

Introduction

It is essential to assess the exposure levels to toxic substances in food. There are three approaches for estimating the dietary intake of such substances: total diet study (TDS), duplicate portion study (DPS), and selective study of individual foodstuffs. A TDS, referred to as a market basket study, has an advantage over the two alternatives in terms of its accuracy. TDS takes into account the effect of kitchen preparation on the levels of toxic substances in food, and provides information on which food groups are the main sources of contamination [1]. Organization of the United Nations (FAO) and the World Health Organization (WHO) since the. According to a survey carried out in 2015 by Health Canada, in cooperation with the WHO, approximately 53 countries around the world perform TDS analyses [2]

Methods

Results

Conclusion