珠江口磨刀门水域溶解态Cd、Pb分布的潮流变化特征

Tidal variation in the distributions of dissolved Cd and Pb in the Modaomen Channel of the Pearl River Estuary

潮流引起的水动力变化,对河口水体中重金属的迁移转化行为具有重要的作用。于2011年9月进行了两个航次的断面与定点连续调查,研究了潮流变化特别是咸潮入侵对磨刀门Cd、Pb分布的影响。结果表明,小潮期间从河端到海端溶解态Cd浓度显著升高,水柱Cd浓度发生分层现象,大潮期间Cd的分布形式主要受海水稀释作用的影响;磨刀门溶解态Pb大潮、小潮的断面分布特征较为复杂,与Cd分布特征存在较大差异。小潮定点连续调查期间,Cd分层明显,Pb的分层则不显著;大潮定点连续调查期间,受到强咸潮的作用,Cd、Pb分布主要受物理稀释作用的影响。

Tides can cause changes in hydrodynamics and have great influence on the fate of heavy metals in estuary. The distributions of dissolved Cd and Pb in the Modaomen Channel were investigated in September 2011. During neap tide, Cd concentration increased from river end member to sea end member; Cd stratification was also found. The fate of Cd was subjected to dilution by sea water of low Cd concentration during spring tide. There were large differences of sectional distribution characteristics between Cd and Pb. The sectional distribution of Pb was complicated. During the neap tide anchor survey, Cd stratification was obvious. During the spring tide anchor survey when strong salt-water intrusion occurred, the fates of Cd and Pb were mainly decided by physical dilution of sea water.