上海市苏州河支流——桃浦河底泥重金属的污染特征

POLLUTION CHARACTERISTICS OF HEAVY METALS INTHE SEDIMENT OF THE TAOPU CREEK——BRANCH OFTHE SUZHOU CREEK IN SHANGHAI

对桃浦河底泥15个柱样(75个样品)测试分析了8种金属元素.结果表明,这些金属元素的平均含量都比较高,超标顺序为Zn＞Cu＞Cd＞Hg＞Pb＞As＞Ni＞Cr,均高于苏州河的浓度.除As、Hg与其他元素的相关性较小外,Pb、Cd、Cu、Zn、Ni、Cr等之间均具有较为显著的相关性,相关系数介于0.616～0.890间.沿河各段重金属污染程度不同,上游和下游污染最严重.底泥金属的垂直分布与其底质沉积特征相对应.这在底泥疏浚时应具体考虑.

The Suzhou Creek is very important for Shanghai's economic. The water was first polluted seriously 80 years ago. In order to clear the water thoroughly,it is essential to improve the water quality of its branches. The Taopu Creek is one of the major polluted branches of the Suzhou Creek in the north bank, and its pollution load affects directly the water quality of the Suzhou Creek. Heavy metal is a kind of specific pollutant and can cumulate with time. The present investigation is aimed to understand the pollution characteristics of the heavy metals in the sediment of the Taopu Creek. A device for sampling the sediment is used and the location of the total sampling sites in the Taopu Creek is given in Fig. 1. For 15 sampling-columns (75 samples) of the sediment in Taopu Creek, 8 metal elements are tested and analyzed. The results shown in Fig. 2 reveal that the average contents of these metals are very high, i. e. the content of As is as high as 186. 5 mg/kg,Cu 1 807. 7 mg/kg,Pb 462. 1 mg/kg,Cd 13. 85 mg/kg,Zn 3 901. 5 mg/kg,Ni 312. 8 mg/kg,Cr 191. 6 mg/kg. The heavy metal contents in the sediment of the Taopu Creek and those different standard values are listed in Table 1. The order of exceeding standard value is,Zn>Cu>Cd>Hg >Pb>As>Ni>Cr. Their contents are higher than those of the Suzhou Creek. The heavy metals Pb.Cd, Cu,Zn,Ni and Cr have remarkable relativity with each other except for As and Hg and correlative coefficient are between 0. 616 and 0. 890 (see Table 2). The polluted degree of different watercourse of the Taop-u Creek is different, the upriver and backward position being the most serious. In vertical, the distribution of heavy metals is corresponding to the sedimentary characteristics in the sediment.