里运河底泥重金属空间分布特征

Spatial distribution of heavy metals in sediments of Liyun River

通过对淮安市里运河底泥的采样与分析,揭示了里运河底泥中镉、砷和硫化物的沿程分布特征、垂向分布特征和横向分布特征以及这些分布特征的形成原因.结果表明:各测点镉的质量分数均超过淮安市土壤环境背景值中镉的质量分数,最大质量分数是背景值的15.73倍;砷和硫化物的质量分数呈沿程降低趋势,但引河路和造纸厂断面砷的平均质量分数超过了淮安市土壤环境背景值中砷的质量分数,砷的最大质量分数为土壤三级标准中砷质量分数的2.45倍;硫化物在引河路断面污染突出,明显高于其他3个断面底泥的硫化物质量分数;重金属在垂向分布上表现为中部的黑泥层质量分数最高;在污染河段的同一断面,河岸的重金属污染程度一般比河中要高.

Based on a sampling analysis of sediments in the Liyun River flowing through the suburb of Huai＇ an City, the longitudinal, vertical and transversal distributions of heavy metals in sediments, including cadmium, arsenic and sulfide, as well as the causes and characteristics of their distribution, were revealed. Some conclusions are drawn from the study： the quality fraction of cadmium at each monitoring point is greater than its background value in soil of Huai＇ an suburb, and the maximum at monitoring points is 15.73 times of the background value; the quality fractions of arsenic and sulfide are decreasing along the river, but the average values of arsenic at the sections of Yinhe Road and the paper plant are beyond their background values in soil; the maximum quality fraction of arsenic is 2.45 times as high as that of soil of grade-Ⅲ, and the quality fraction of sulfide at the section of Yinhe Road is much higher than that of the other three sections. The quality fractions of heavy metals in the middle of black mud layers are the highest in vertical direction, and the pollution caused by heavy metals at the riverbank is more serious than that at the center of the river at the same profile of polluted sections.