舟山群岛潮间带表层沉积物中重金属污染现状及潜在生态风险评价

摘要

对舟山群岛潮间带表层沉积物中重金属质量比进行了测定,采用单因数指数法和生态风险指数法评价潮间带沉积物中重金属的污染现状及其对环境的潜在生态危害程度.结果表明,Cu,Pb,Cd,Zn,Hg,As的平均质量比分别为27.8 mg/kg,21.8 mg/kg,0.137 mg/kg,83.2mg/kg,0.051 mg/kg,10.8 mg/kg.单因子指数评价结果显示,研究区域内重金属污染现状整体表现为中等污染水平.生态风险指数评价结果表明,区域内重金属的潜在生态风险整体表现为轻微生态危害.其中,Cu,Pb,Zn,As的生态危害轻微；Cd主要表现为轻微生态危害,部分潮间带断面达到中等生态危害等级；Hg主要表现为中等生态危害等级.各种元素对区域环境的潜在生态风险危害的大小顺序为Hg＞Cd＞As＞Cu＞Pb＞Zn.Hg是区域内首要的潜在生态风险因子,Cd次之.%The concentrations of heavy metals in surface sediments in intertidal zone of Zhoushan Islands are analyzed and the heavy metal pollution and its potential ecological risk are evaluated by means of single factor index and potential ecological risk index. The results show that the average concentrations of Cu, Pb,Cd,Zn,Hg and As are 27. 8 mg/kg, 21. 8 mg/kg, 0. 137 mg/kg, 83. 2 mg/kg, 0. 051 mg/kg and 10. 8 mg/kg respectively. The single factor indices and the assessment on potential ecological risk degree have respectively indicated that in the survey area the heavy metal pollution status belongs mainly to a moderate pollution degree and the ecological risk of heavy metals is slight as a whole, with the ecological risk of Cu, Pb, Zn and As being slighter. Cd shows mainly slight ecological risk, but at some monitoring stations its ecological risk reaches to a moderate degree, Hg shows a moderate ecological risk mainly. The potential risk of heavy metals to the regional environment is in the order of Hg>Cd>As>Cu>Pb>Zn, with Hg being the chief risk factor and followed by Cd.