Comparison of different radionuclide dating models for estimating the ages of sediments from Lakes Shinji-ko and Nakaumi, Japan

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Understanding the history and processes of sediment accumulation in lakes and estuaries is fundamental for evaluating environmental changes in water bodies. This study presents the spatial distribution of excess ²¹⁰Pb ( ²¹⁰Pb_ex ) and ¹³⁷Cs concentrations (activities) in sediment cores from 41 sites in Lake Shinji-ko and seven sites in Lake Nakaumi, which together form the largest brackish water body in Japan. These data provide significant information on sediment age, essential for paleoenvironmental research and lake conservation. ²¹⁰Pb_ex and ¹³⁷Cs can provide very effective estimates of sediment ages over the past 100 years; however, their improper use or interpretation may result in incorrect age estimates. We review this problem by comparing various dating models, using data collected from the two lakes and evaluating their potential for sediment dating. The ey requirement for accurate sediment dating is to examine the depth distribution of ²¹⁰Pb_ex before selecting the dating model. Additional recommendations for the effective dating of sediments are provided.