沉积物重金属污染评价方法对比——以上海崇明东滩为例

Comparison of the Evaluation Methods of Heavy Metal Sediment Pollution——Take Chongming Dongtan as an Example

对崇明东滩表层样中重金属Hg、Cu、Cd、Pb、Zn的含量进行了分析,并利用地累积指数法、综合污染评价法和潜在生态危害指数法对崇明东滩的污染状况进行了分析。地累积指数法和潜在生态危害指数法的评价结果显示,崇明东滩基本保持了自然状态,仅有个别站位的Hg、Pb元素有轻微污染;综合污染评价法的评价结果显示,崇明东滩的污染全部达到了警戒水平,单因子评价中,Cd对综合污染指数的贡献最高,说明研究区Cd污染较为严重。三种评价方法相比较,地累积指数法比较简单;综合污染评价法兼顾到污染指数最大值对土壤环境质量影响,强调了最大综合污染指数,与其他方法相比,其综合指数常常偏高;而潜在生态危害指数法加入了对环境和人类健康有重要影响的毒性系数,有一定的实际意义。三种方法各有优缺点。

The contents of heavy metals of the Dongtan surface samples such as Hg, Cu, Cd, Pb, Zn are analyzed, and three evaluation methods such as the cumulative index, integrated pollution evaluation and potential ecological risk index are used to evaluate the ponuted situation of Chongming Dongtan. The result of the cumulative index and the potential ecological risk index show that Dongtan is basically remaining a natural condition, only a few stations get a slight ponution of Hg and Pb; The result of integrated pollution assessment shows that the pollution of Chongming Dongtan reaches the alert level, and in the single factor evaluation, Cd contribution rate is the largest to the integrated pollution index, which indicates that the Cd pollution is more serious. Compared with the evaluation methods above, the cumulative index method is relatively simple, the integrated pollution evaluation method takes into account the maximum impact on soil quality, and emphasizing the most comprehensive pollution index with other methods, and the composite index is often high. The potential ecological risk index considers the toxic factor which has important influence on the environment and human health, so it has some practical significance. Each of three methods has its own advantages and disadvantages.