潮汐作用对通江湖泊重金属镉的三相分布特征影响

为研究不同水动力扰动下金山湖重金属的三相迁移转换机制,采用环形水槽模拟湖内水流过程,进行重金属迁移模拟试验,并利用二维水流、悬浮物、重金属耦合水环境数学模型分区模拟金山湖一个全日潮镉迁移过程。结果表明:中高扰动强度下,水深越小,沉积物起悬强度越大;水深一定时,扰动强度增加,沉积态镉与溶解态镉均呈现下降趋势,悬浮吸附态镉则呈现上升趋势;低扰动强度时,镉的三相交换规律不明显,但沉积态镉较为稳定。在每个湖区内部,三态浓度大致呈两波峰两波谷趋势;从全湖来看,沉积态镉与溶解态镉变化趋势相近,且与悬浮态镉变化趋势相反。研究成果对于进一步揭示通江湖泊重金属迁移运输机制具有参考价值。

Tidal Effect on the Distribution of Heavy Metal Cadmium of Three Phases in River-connected Lake

In an attempt to study the three-phase transformation of heavy metal cadmium (Cr) in Jinshan Lake under different hydrodynamic disturbances, the transformation of Cr in Jinshan Lake during a diurnal tide is simulated using an annular sink which simulates lake water flow coupled with hydroenvironment mathematical model. Results show that under medium and high disturbances, the intensity of incipient suspension grows with the increase of water depth. At a given water depth, as the intensity of disturbance grows, deposited Cr and dissolved Cr both present a decreasing trend, while suspended Cr increases. Under low disturbance, however, the rule of Cr transformation among three phases is not obvious, with deposited Cr staying stable. In addition, in different partitions of lake, the concentration of Cr of different phases presents two peaks and two valleys; in holistic sense, the change trend of deposited Cr is similar to that of dissolved Cr, opposite to that of suspended Cr.