Natural radioactivity level in beach sand along the coast of Xiamen Island, China

The activity concentration of 40K, 232Th and 226Ra was determined in beach sand samples collected from Xiamen Island, China using gamma ray spectrometry. The activity concentrations of 40K, 232Th and 226Ra in the beach sand range from 197.4 to 487.6, 6.5 to 41.4 and 7.9 to 25.7 Bq kg−1 with the mean of 401.0, 11.3 and 14.1 Bq kg−1, respectively, which are lower than the averages of Chinese soil and world soil. The radium equivalent activity values in all beach sand samples are lower than the recommended limit of 370 Bq kg−1. The external hazard index values are less than unity. The outdoor air absorbed dose rate and the corresponding annual effective dose rate of beach sand investigated are lower than the worldwide average.