Plutonium isotopes in the Qinling Mountains of China

In order to study the effect of air masses on the distribution of artificial radionuclides on both sides of the mountain range, Pu and 137 Cs in forest soils of the Qinling Mountains in Shaanxi Province were determined for the first time. The 239+240 Pu and 137 Cs activity concentrations ranged from 0.001 ± 0.001 to 0.501 ± 0.031 Bq/kg and 0.27 ± 0.06 to 7.82 ± 0.34 Bq/kg, respectively. The 240 Pu/ 239 Pu atom ratios in samples ranged from 0.160 ± 0.024 to 0.218 ± 0.037 with an average value of 0.188 ± 0.014, indicated that Pu isotopes from the Qinling Mountains mainly came from global fallout. The results of this research add the 239+240 Pu activity concentrations and 240 Pu/ 239 Pu atom ratio of the Qinling Mountains, the atmospheric circulation in the Qinling Mountains did not significantly affect the Pu content. Also, it provides significant data on the radioactivity of Chinese soils.