Migration Of ~(137)cs In Tributaries, Lake Water And Sediment Of Lago Maggiore (italy, Switzerland)-analysis And Comparison With Lago Di Lugano And Other Lakes

摘要

This paper describes the behaviour of ~(137)Cs in Lago Maggiore and other pre-alpine lakes as a consequence of atmospheric nuclear weapons testing fallout and the fallout from the nuclear accident in Chernobyl. It presents data on the ~(137)Cs distribution in tributaries, lake water, bottom sediments and reveals the role of ~(137)Cs as a marker of the sedimentation processes. The run-off of ~(137)Cs from the watershed to the lake is described with a simple compartment model. Measurements of the activity concentration of ~(137)Cs in sediments are compared with the output of a model (diffusion-convection type) which describes the input of ~(137)Cs into and its vertical distribution within the sediment. Varying sedimentation rates (0.05-0.90 g (cm~2 y)~(-1)) in Lago Maggiore are compared with data of other authors. Sedimentation rates and total distribution coefficients (of about 10~5 L kg~(-1)) in Lago Maggiore are discussed and compared with those of Lago di Lugano, Lake Constance, and Lake Vorsee.