Thallium concentrations, sources and ecological risk in the surface sediments of the Yangtze Estuary and its adjacent east China marginal sea: A baseline study

摘要

The distribution characteristics, sources and ecological risk of thallium (T1) in the surface sediments of Yangtze Estuary and its adjacent sea were studied. Tl concentrations ranged from 0.369 to 1.197 mu g g(-1) with an average of 0.674 mu g g(-1), which was slightly higher than the corresponding background values. Ti concentrations were relatively high in sediments of the south bank of Chongming Island and the Hangzhou Bay mouth, and gradually decreased from inner shelf to outer seas. The variation trend of Tl concentrations was controlled by sediment characteristics, hydrodynamic conditions and sources together. The sediment flux of Ti in the study area was 428.6 t/yr. The Yangtze River, the Yellow River and atmospheric inputs of Tl accounted for 52.7%, 10.5%, and 0.15% of the total sediment flux, respectively. The result of potential ecological index indicated that T1 in surface sediments of the study area had no threat to the ecological environment.