Fallout 137Cs signals as chrono-markers in Chinese lake sediment cores

• DOI: 10.1016/j.scitotenv.2025.178528
• Publication Date: 2025-01-17T19:49:20Z
• Authors: Yanan Huang; Elena Chamizo; Rafael García-Ten...; Xiaoming Sun
• Keywords: 137Cs; Sedimentation rate; Sediment; Chinese lakes; Chronology

Peer reviewed<br/>This work was supported by the international postdoctoral exchange fellowship program of Guangdong Province (20210616) and Doctoral Scientific Startup Fund from Nanning Normal University (602021239517).<br/>This study comprehensively investigated the 137Cs signal in 294 sediment core samples from 132 lakes including reservoir and Gobi catchment in China. First, three 137Cs chrono-markers were observed: the 1963 peak corresponding to the maximum deposition of radioactive debris from global fallout, and two local sub-peaks corresponding to the time of the nuclear tests at Chinese Lop Nor site with a maximum in 1976, and to the Chernobyl accident in 1986. Second, the spatial distribution of sedimentation rates based on the 1963 137Cs chrono-marker in Chinese lake sediment cores was studied. It was observed that it does not usually exceed 1 cm a-1 (∼95 %). Although the formation of 137Cs peak does not matter if the lake is closed or not, sedimentation rate is related to it over time. The distribution pattern of sedimentation rates is basically consistent with the area segmented by the 400 mm precipitation contour line in China. Based on the current data (n = 18, R2 = 0.863), a significant linear correlation was observed between sedimentation rates and 137Cs inventories in Lake Qinghai, the largest lake in China. This study provides reference data that supports future research on lake sediment cores in China.<br/>