In Situ Measurement and Analysis of ¹³⁷Cs and Other γ-emitting Radionuclides in Soil of Changbai Mountain by HPGe Spectrometer

Changbai Mountain, which is the highest mountain located on the eastern edge of Eurasia, was set up as the first National Nature Reserve. Due to little interferences of human activities, the soil of the Changbai Mountain could reflect the artifical nuclides of ¹³⁷Cs deposited on the ground from global atmospheric nuclear tests and Chernobyl nuclear accident. To investigate the distribution pattern of ¹³⁷Cs in Changbai Mountain soil after years of decay and migration, in situ γ-ray spectrometer was applied to measure the γ-emitting radionuclides in soil of the desert regions, tundra regions, birch forest regions and conifer forest regions of northern slope, southern slope and western slope. The results show that the contents of ²³⁸U and ²³²Th maintain a relative high level in the region covered by volcanic ash. The maximum values reach 112 Bq/kg and 154 Bq/kg for ²³⁸U and ²³²Th, respectively. The activity concentration of ¹³⁷Cs maintains a relative high level in the flat and lush vegetative terrain. The maximum value of activity concentration is up to 1.07×10⁴ Bq/m².