Lead-210 and plutonium fallout in Taiwan as recorded at a subalpine lake
Journal
Journal of Southeast Asian Earth Sciences
Journal Volume
14
Journal Issue
5
Pages
373-376
Date Issued
1996
Author(s)
Abstract
A sediment core collected from the Sun Moon Lake in middle Taiwan was investigated for 210Pb and 239,240Pu. Based on the decrease of excess 210Pb with depth, the mean sedimentation rate in the lake during the past half century is about 0.9 cm yr-1, which is unequivocally supported by the appearance of the 1963 plutonium fallout maximum at 26-28 cm. The short-term sedimentation rate is one order of magnitude greater than 14C-based long-term sedimentation rates in the lake reported previously. This may be attributed to the deterioration of soil conservation associated with the construction of a dam five decades ago. Total downcore inventories of excess 210Pb and 239,240Pu are 54.5 dpm cm-2 and 0.21 dpm cm-2, respectively. This 210Pb inventory requires a flux of 1.7 dpm cm-2 yr-1 at steady state, which is similar to 210Pb fluxes observed at other sites in the western Pacific rim. The inventory of 239,240Pu is in excellent agreement with documented cumulative 239,240Pu from global fallout (0.96 ± 0.07 mCi km-2) at the 20-3°N latitudinal band. Our data suggest that the Sun Moon Lake is an ideal setting for monitoring atmospheric fallout and environmental changes in this region. © 1997 Elsevier Science Ltd. All rights reserved.
Type
journal article