Beryllium-7 activity concentration in plants on the Loess Plateau, China

Abstract

The activity concentration of beryllium-7 (7Be), a naturally occurring cosmogenic radionuclide produced in the upper atmosphere, was measured in plants on the Loess plateau of China during the growing season of 2005. The 7Be mass activity concentration on July 27 ranged from 34.8 to 147.1 Bq kg−1 in herbaceous plants, from 47.6 to 116.1 Bq kg−1 in subshrubs, and from 15.7 to 56.8 Bq kg−1 in crop plants. The 7Be mass and areal activity concentrations of a mixture of herbaceous plants increased from 66.8 to 288.7 Bq kg−1 and from 0.7 to 46.5 Bq m−2, respectively, during the growing season. On an areal basis, the fraction of 7Be in plants in the soil–plant system increased from 0.4 to 8.4% during the growing season. Positive linear correlations were found between the increases of 7Be mass and areal activity concentrations in the inter-sampling intervals and the amount of precipitation.