鄱阳湖水系重金属元素地球化学特征及入湖通量

Geochemical Characteristic and Fluxes of Heavy Metals in Water System of the Poyang Lake

江西省多目标区域地球化学调查显示,鄱阳湖流域河流两岸土壤(河漫滩沉积物)中存在明显的重金属异常带。为揭示河流两岸河漫滩沉积物(土壤)中重金属元素的来源、输送通量及其沉积历史,分别于丰水期和枯水期系统采集了鄱阳湖流域赣江、信江、饶河、抚河、修水及鄱阳湖湖水、悬浮物等样品,分析As、Cd、Pb等元素含量。研究表明:As、Pb、Cu、Zn等元素在研究区河流中的含量普遍较高,不同时期河水中的元素含量有较大的差异;各重金属元素在研究区河流迁移形式有很大的差别,As和Cd主要以离子态形式迁移,但Cd悬浮态迁移形式所占比例也很大;Pb、Zn、Cu和Ni主要以悬浮态形式迁移;重金属在河流水体和悬浮物两相中的分配受水体pH值、温度和悬浮物浓度等因素影响,不同的元素受这些因素的影响程度有很大的差别;按各支流输送通量,赣江和信江对湖区重金属元素输入通量的贡献最大,是鄱阳湖Cd等重金属元素的最主要来源。

In this study, heavy metal pollution condition of Poyang Lake was investigated. During rainy and arid seasons, river water and suspended matters samples from the Poyang Lake area were collected and analyzed. In the studying rivers, the concentration of As, Pb, Cu, Zn and other elements were relatively high, whereas Cd was low. The levels of heavy metal showed significant difference between rainy and arid seasons. For the individual elements, Pb, Zn, Cu and Ni were transported mostly in the form of the suspended matters, while As was moved in the dissolved form mostly. Nevertheless, Cd was in both dissolved and suspended forms in all the samples. It is found that the distribution of heavy metal in solidliquid was affected by pH, temperature in water and concentration of suspended solids. However, the influence was different among elements. It is also found that the main input of heavy metal pollution in Poyang Lake was originated from Ganjiang and Xinjiang.