黑臭水体底泥重金属生态风险评价与污染源解析

Ecological Risk Assessment and Source Apportionment of Heavy Metals in Sediments of a Black-odorous River

我国黑臭水体数量较多,亟待治理,对黑臭水体底泥中重金属开展生态风险评价和溯源分析是黑臭水体整治的重要保障。因此,以靖江某黑臭水体为例,对底泥重金属开展生态风险评价,并将多变量统计分析和正定矩阵因子分析法(PMF)联合应用于底泥重金属源解析。结果表明,该河道底泥中Pb、Zn、Cu、Hg和Cd累积程度较高,已呈现低度及以上污染水平,特别是Pb、Hg、Cd已存在生态风险,需要特别关注。多变量统计分析结果表明,河道底泥中的重金属累积同时受到以土壤母质和岩石风化为代表的自然源及以工业和交通为代表的人为源影响,其中人为源是底泥中重金属的主要来源。PMF分析结果表明,铅盐企业排放和交通源对底泥中的Pb贡献率分别为44.65%和45.31%,大气沉降和生活污水对底泥中的Hg贡献率分别为35.92%和44.73%。对比2种分析结果可以发现,对于累积程度及生态风险较高的重金属(Pb、Hg、Cd)元素,多变量统计方法和PMF方法在来源解析上具有较高的一致性。

There exist a number of black-odorous water bodies in China,which need to be treated urgently.Source apportionment to heavy metals in sediments is an important guarantee for the remediation of black-odorous rivers.Therefore,this study took a black-odorous river in Jingjiang of Jiangsu Province as an example to conduct ecological risk assessment and source apportionment of heavy metals in sediments,using multivariate statistical analysis and positive definite matrix factor analysis(PMF).The results show that the contents of Pb,Zn,Cu,Hg and Cd in the sediments were accumulated to moderate pollution level,especially for Pb,Hg and Cd,which had heavily ecological risks and should be highly concerned.Multivariate statistical analysis results indicate that the accumulation of heavy metals in sediments was originated from both natural sources represented by soil parent and rock weathering and anthropogenic sources represented by industrial discharge and traffic emission.The anthropogenic source was the main contributor to the accumulation of heavy metals in sediments.PMF results demonstrate the discharge of lead salt enterprise and traffic emission contributed 44.65%and 45.31%to the content of Pb in sediments,respectively;and atmospheric deposition and domestic sewage contributed 35.92%and 44.73%to the content of Hg in sediments.It shows that the multivariate statistical analysis result is relatively consistent with the PMF analysis result.