珠江口表层沉积物铜铅锌镉的分布与评价

根据2002年5月和8月珠江口生态环境调查的数据,对沉积物中重金属元素Cu,Pb,Zn,Cd的质量分数与分布进行了分析讨论。结果表明,珠江口沉积物Cu,Pb,Zn,Cd的平均质量分数分别是43 8,48 9,153 3,0 82mg kg,变化范围分别是22 5～66 7,28 1～85 3,68 5～255 5,0 02～4 10mg kg。受水动力条件及冲淤特性的影响,8月份表层沉积物中Cu,Pb,Zn,Cd的质量分数高于5月份。珠江口表层沉积物中Cu,Pb,Zn,Cd质量分数平面分布趋势基本相似,呈现西部高于东部趋势,淇澳岛附近质量分数最高、大屿山附近质量分数最低。断面分布显示,调查区域上游断面沉积物中Cu,Pb,Zn,Cd的质量分数高于下游断面的质量分数,表明上游沉积物中4种元素主要源自河流的输入。季节差异也呈现上游的质量分数大于下游的质量分数。生态危害的评价结果表明,Cu,Pb,Zn的潜在生态危害轻微,Cd的危害性高于Cu,Pb,Zn。 

The Concentration Distribution and Assessment of Cu,Pb,Zn and Cd in Surface Sediments from Pearl River Estuary

The concentrations and distribution of heavy metal Cu,Pb,Zn and Cd in surface sediments from Pearl River estuary were analyzed,according to the eco-environmental survey data collected in May and August,2002.It was shown that the average concentrations of Cu,Pb,Zn and Cd in surface sediments from Pearl River estuary were 43.8,48.9,153.3 and 0.82 mg/kg respectively,with the range 22.5～66.7,28.1～85.3,68.5～255.5 and 0.02～4.10 mg/kg respectively.Affected by the water dynamic and flush/silt in Pearl River estuary,the concentrations of Cu, Pb,Zn and Cd in surface sediments in August were higher than those in May.The horizontal distributions of Cu,Pb,Zn and Cd in surface sediments from Pearl River estuary were very similar,with the highest concentrations near Qi’ao Island and lowest concentrations near Dayushan Mountain.The section distribution showed that the concentrations of Cu,Pb,Zn and Cd in the surface sediments from upper estuary section were higher than those of downriver section,and it is indicated that the four kinds of heavy metal in the surface sediments from upper estuary originated in the river input.The seasonal difference also showed that the heavy metal concentrations in the sediments from upper estuary were higher than those of downriver region.The ecological risk assessment results showed that the potential risks of Cu,Pb and Zn were slight and the risk of Cd is higher than those of others.