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

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.