深圳河流沉积物中重金属累积特征及污染评价

为了解深圳河流沉积物中重金属的污染现状和污染程度,对1996～2007年深圳河、布吉河、龙岗河和茅洲河4条河流沉积物中重金属元素(Cu、As、Cd、Cr、Hg、Pb和Zn)的含量和年际变化进行了调查和研究,并利用地累积指数和潜在的生态危害指数对其进行了综合评价。结果表明,4条河流均不同程度地受到了重金属的污染,并呈逐年增加的趋势。地累积指数和潜在的生态危害指数的研究显示,4条河流的污染程度大致为:龙岗河布吉河深圳河茅洲河,其中尤以Cu、Cd、Cr和Zn的污染程度最重。龙岗河和布吉河的污染和潜在的生态危害基本上达到了严重的程度,龙岗河多年平均地累积指数高达6.36,潜在的生态危害指数多年平均值为2333.2;而深圳河则大致为中度或者重度污染;茅洲河的污染程度最轻,其潜在的生态危害指数多年均值为274.1,除Cd和Hg处于中度和强度潜在的生态危害外,其余元素大都是轻度污染和轻度危害。

Accumulated Characteristics and Pollution Assessment of Heavy Metals in Shenzhen River Sediments,

Spatial and temporal distribution of heavy metals including Cu, As, Cd, Cr, Hg, Pb and Zn in Shenzhen River, Buji River, Longgang River and Maozhou River sediments from 1996 to 2007 were investigated and studied in order to understand heavy metal pollution and degree. Based on analysis, a comprehensive assessment on heavy metals in Shenzhen urban river sediments was presented using index of geo-accumulation and potential ecological risks index. Results showed that the four rivers were polluted by heavy metals and contents increased with the year, with the pollution degree followed the order as river of Longgang, Buji, Shenzhen and Maozhou, with the most serious polluted heavy metals as Cu, Cd, Cr and Zn. Potential ecological risks and pollution degree of Longgang and Buji were very severe, with average geo-accumulation and potential ecological risks index of Longgang as 6.36 and 2333.2 respectively. River of Shenzhen was in middle degree or severe potential ecological risks. Maozhou was under relatively well sate and most metals were under low or middle potential ecological risks except for Cd and Hg, with average geo-accumulation index as 274.1.