Bishop Benjamin Thomas, Brey Richard
1Idaho State University, Health Physics Program, Campus Box 8106, Pocatello, ID 83209-8106.
Idaho State University, Health Physics Program, Campus Box 8106, Pocatello, ID 83209-8106.
Health Phys. 2018 Oct;115(4):458-464. doi: 10.1097/HP.0000000000000908.
A total of 68 sediment cores from four freshwater alpine lakes in Idaho's Sawtooth Wilderness were collected during the summer of 2017. The objectives of the study were to determine depth distributions of Cs in the cores using gamma spectrometry and to estimate the sedimentation rates of the lakes from the identified geochronological peaks linked to nuclear fallout. The Cs radioactivity above reference-area values was detected in all studied lakes. The maximum Cs concentrations measured in each lake's sediment ranged from 74.0 ± 6.09 to 255 ± 7.48 Bq kg. Factors such as elevation, latitude, and pH showed no correlation to total Cs deposition. However, the data developed during this investigation suggested that characteristics such as geological location or lake flushing patterns are important factors in the total Cs deposition observed. Three of the lakes had Cs sediment depth distributions that resembled the deposition pattern of weapons testing as a function of time. Mean sedimentation rate estimates ranged from 0.08 ± 0.3 to 0.1 ± 0.05 cm y and decreased with increasing altitude.
2017年夏季，从爱达荷州锯齿荒野的四个淡水高山湖泊中总共采集了68个沉积物岩芯。该研究的目的是使用伽马能谱法确定岩芯中铯的深度分布，并根据与核沉降相关的已识别地质年代学峰值来估算湖泊的沉积速率。在所有研究的湖泊中都检测到了高于参考区域值的铯放射性。每个湖泊沉积物中测得的最大铯浓度范围为74.0±6.09至255±7.48贝克勒尔/千克。海拔、纬度和pH值等因素与总铯沉积没有相关性。然而，本次调查得出的数据表明，地理位置或湖泊冲刷模式等特征是观察到的总铯沉积的重要因素。其中三个湖泊的铯沉积物深度分布类似于武器试验随时间的沉积模式。平均沉积速率估计范围为0.08±0.3至0.1±0.05厘米/年，并随海拔升高而降低。
