90Sr in Chinese tea of typical regions: activity concentration and hygienic evaluation

Objective To investigate the activity concentration of ⁹⁰Sr in tea produced in Chinese typical regions, enrich the baseline data for ⁹⁰Sr level in Chinese tea, and evaluate possible exposure doses to people. Methods Samples were carbonized, ashed, digested and leached, and then extraction chromatography method was used to separate ⁹⁰Sr and ⁹⁰Y. After preparation of sample source, radioactivity of ⁹⁰Y was measured using low-level α/β counter. Results Twenty six kinds of tea produced in 16 typical regions from 26 cities of 16 provinces were collected in 2016, and their ⁹⁰Sr activity concentrations were analyzed using the separation method of di(2-ethylhexyl) phosphate (HDEHP) extraction chromatography. The results revealed that the activity concentrations in 26 kinds of tea samples ranged from 0.28 to 3.78 Bq/kg, and contributed possible exposure doses of 0.44×10^-2- 6.00×10^-2 μSv to each people. Conclusions These doses were far less than the ICRP annual dose limit of 1 mSv for the public, suggesting less impact on people''s health.