Cesium radioactivity in peripheral blood is linearly correlated to that in skeletal muscle: Analyses of cattle within the evacuation zone of the Fukushima Daiichi Nuclear Power Plant

Abstract

The accident at the Fukushima Daiichi Nuclear Power Plant (FNPP) released a large amount of radioactive substances into the environment. Furthermore, beef contaminated with radioactive cesium above the 500 Bq/kg safety standard was circulated in the food chain in 2011. Japanese consumers remain concerned about the safety of radioactively contaminated food. In our previous study, we detected a linear correlation between radioactive cesium ((137) Cs) activity in blood and muscle around 500 to 2500 Bq/kg in cattle. However, it was unclear whether the correlation was maintained at a lower radioactivity close to the current safety standard of 100 Bq/kg. In this study, we evaluated 17 cattle in the FNPP evacuation zone that had a (137) Cs blood level less than 10 Bq/kg. The results showed a linear correlation between blood (137) Cs and muscle (137) Cs (Y = 28.0X, R(2) = 0.590) at low radioactivity concentration, indicating that cesium radioactivity in the muscle can be estimated from blood radioactivity. This technique would be useful in detecting high-risk cattle before they enter the market, and will contribute to food safety.

A method for estimating radioactive cesium concentrations in cattle blood using urine samples

“…The muscle/blood ratio of radioactive cesium in cattle is approximately 20 (Fukuda et al . ; Sato et al . , ,b).…”

“…The legal limit for radioactive cesium in general foods, including beef, is 100 Bq/kg. The muscle/ blood ratio of radioactive cesium in cattle is approximately 20 (Fukuda et al 2015;Sato et al 2015Sato et al , 2016a. Assuming a ratio of 25, the radioactive cesium concentration in the blood must be lower than 4 Bq/kg, and it is desirable that it is < 2 Bq/kg.…”

“…However, the apparatus for performing the measurements is large, and cannot be easily transported. The concentration of radioactive cesium in muscles correlates well with that in blood, so the contamination level of beef can be estimated by measuring blood samples (Fukuda et al 2015). However, because the radioactive cesium levels in blood are considerably lower than in skeletal muscles, it takes a longer time to measure precisely blood samples.…”

Comparison of urine and blood as a convenient and practical sample for estimating the contamination level of live cattle with radioactive cesium

“…The M/B ratio showed large individual differences ranging from 13.2 to 34.5 with an average of 21.7. Fukuda et al (2015Fukuda et al ( , 2016 reported that the concentration of radioactive cesium in muscles is linearly correlated with that in the peripheral blood, and developed a software for estimating the contamination level of muscles from the value in blood. Fukuda et al (2015Fukuda et al ( , 2016 reported that the concentration of radioactive cesium in muscles is linearly correlated with that in the peripheral blood, and developed a software for estimating the contamination level of muscles from the value in blood.…”

“…This ratio was not dependent on the age, sex (data not shown), and the contamination level of cattle ( Figure 1), but it seemed to be high from late autumn to early spring and to be low from summer to early autumn ( Figure 2). Fukuda et al (2015Fukuda et al ( , 2016 reported that the concentration of radioactive cesium in muscles is linearly correlated with that in the peripheral blood, and developed a software for estimating the con- (Sato et al, 2015). Even if the concentration of 137 Cs in the cattle tissue were 10,000 Bq/kg, which is 100 times as high as the legal standard, the concentration of cesium as an element would increase only by 0.0031 μg/kg ( 134 Cs: 0.00021 μg/10,000 Bq).…”