90Sr in teeth of cattle abandoned in evacuation zone: Record of pollution from the Fukushima-Daiichi Nuclear Power Plant accident

Abstract

Here we determined the 90Sr concentrations in the teeth of cattle abandoned in the evacuation area of the Fukushima-Daiichi Nuclear Power Plant (FNPP) accident. 90Sr activity concentrations in the teeth varied from 6–831 mBq (g Ca)−1 and exhibited a positive relationship with the degree of radioactive contamination that the cattle experienced. Even within an individual animal, the specific activity of 90Sr (Bq (g Sr)−1) varied depending on the development stage of the teeth during the FNPP accident: teeth that were early in development exhibited high 90Sr specific activities, while teeth that were late in development exhibited low specific activities. These findings demonstrate that 90Sr is incorporated into the teeth during tooth development; thus, tooth 90Sr activity concentrations reflect environmental 90Sr levels during tooth formation. Assessment of 90Sr in teeth could provide useful information about internal exposure to 90Sr radiation and allow for the measurement of time-course changes in the degree of environmental 90Sr pollution.

Incorporation and Accumulation of Strontium-90 in the Hard Tissue of Animals and Their Relationship with Strontium-90 Pollution in the Environment

“…Figure 5.2 shows the relationship between 90 Sr activity concentration in hard tissues (teeth and mandibular bones) of cattle and in soil from the ex-evacuation zone (Okuma Town and Kawauchi Village) after the FNPP accident. Activity concentrations of 90 Sr in the teeth were 150-830 mBq/g Ca (ratio of 90 Sr radioactivity to Ca weight in the tooth) (average, 470 mBq/g Ca) for Okuma Town and 100-310 mBq/g Ca (average, 170 mBq/g Ca) for Kawauchi Village [17]. The deposited amount of 90 Sr in soil was 94-1500 Bq/m 2 (average, 740 Bq/m 2 ) for Okuma Town and 39-380 Bq/m 2 (average, 200 Bq/m 2 ) for Kawauchi Village [9].…”

“…We previously reported activity concentration and specific activity of 90 Sr in the teeth of cattle stayed in the ex-evacuation zone (Fig. 5.1) of the FNPP accident [17]. Because of chemical similarity between Sr and calcium (Ca), the teeth incorporate Sr during their formation period (calcification period) and retain it until they fall out or are worn down.…”

“…5.2b). Metabolic turnover rates (modeling and remodeling) of the mandibular bone in the cattle are not well- Sr activity concentration in the teeth were obtained from our previous report [17]. Data of 90 Sr activity concentration in soil were obtained from Japanese government reports [9,18].…”

Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

“…The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. We have established an archive system composed of livestock and wild animals within a 20 km radius from FDNPP, that is, the ex-evacuation zone of the FDNPP accident [1][2][3][4][5][6][7][8][9][10][11][12][13]. This system provides critical information for the understanding of environmental pollution, biodistribution, radionuclide metabolism, dose evaluation, and the biological effects of internal and external exposure to radiation caused by nuclear disasters.…”

Estimation of concentration of radionuclides in skeletal muscle from blood, based on the data from abandoned animals in Fukushima

“…Although our sperm data is negative, the data presentation of no abnormality would be an important milestone to study the risk evaluation of human safety. Furthermore, we detected the existence of 90 Sr in teeth tissue of cattle, indicating the scientific evidence that 90 Sr was also released from the FNPP accident (Koarai et al., 2016). Our research group showed the existence of double‐strand break DNA damage in lymphocyte cells derived from the abandoned cattle, which were detected by the immune‐staining of gamma‐H2AX foci (Nakamura et al., 2017).…”