Vertical distribution of 137Cs and plutonium in Lake Taihu and Dianchi sediment cores: loss of radionuclides in shallow, eutrophic lakes

Plutonium and 137 Cs deposited in lacustrine sediments have been used for dating and radionuclide source identification. In order to determine if the radionuclides can be applied to chronogram in shallow lakes with disturbances, we investigated the vertical distribution profiles and loss ratio of plutonium isotopes and 137 Cs in sediment cores from Lakes Taihu and Dianchi. We obtained that the inventory of 239+240 Pu and 137 Cs were lower than those for global fallout for the corresponding latitude and the loss ratios of 137 Cs in Lake Taihu was 96%, evident that the loss of 137 Cs inventory led to invalid chronological time scales.