Fluctuation of Cadmium Load on a Tide‐Influenced Waterfront Lake in the Middle‐Lower Reaches of the Yangtze River

Abstract

The Inner Lake, a typical waterfront lake located in the middle‐lower reaches of the Yangtze River, is selected as the research area in this paper. Through field measurements and laboratory experiments, spatial distribution characteristics of the heavy metal cadmium (Cd) contents were revealed, and the release rate‐flow disturbance curve in sediment of the Inner Lake was formed. The mathematical models of the migration and transformation of Cd were built and calibrated. With the models, the fluctuation characteristics of Cd pollution load were quantitatively assessed in different time scales, as in typical years (1998, 2001, and 2004) and in typical tidal cycles of dry seasons and flood seasons. The results showed that: there was a positive correlation between the release rate of Cd and flow disturbance intensity. Influenced by the hydrologic regime of the Yangtze River, the Cd pollution load was higher in high‐water years than that in common‐water years and low‐water years, and was higher in flood seasons than that in dry seasons. Influenced by the tide of the Yangtze River, the Cd pollution load increased during ebb tide and reduced during the rising tide.