ABSTRACT
The results of gross alpha and beta radioactivity measurement in water spinach samples from some districts in Ho Chi Minh City, Vietnam are presented in this paper. The measurements were performed using a low-background proportional counters LB4200 manufactured by Canberra Company, Inc. Mean concentrations of gross alpha and beta activity were found to be 1.50 ± 0.38 Bq kg-1 to 84.25 ± 8.67 Bq kg-1. In order to keep the recommended dose level, a recommended maximum intake of water spinach was proposed to be 6 kg fresh per year. The total annual committed effective dose due to natural radionuclides in water spinach samples was then found in range from 0.07 mSv y-1 to 0.82 mSv y-1. The dose from 26.32% of samples exceeds the exemption mean dose criterion of 0.3 mSv y-1 but complies with the upper dose principle of 1 mSv y-1 provided in UNSCEAR 2008 report. The estimated soil-to-plant transfer factors for gross alpha and beta for water spinach samples were also presented.
