淡水湖泊沉积物污染评价方法比较--以北大港水库为例

Comparison of evaluation methods of the freshwater lake sediment pollution:A case study of Beidagang reservoir

为了比较沉积物污染的3种典型评价方法,对北大港水库内的11个采样点进行表层沉积物采样,并测定了样品的全盐量、有机质、全磷和全氮指标。根据测定得出的数据分别利用单因子指数法、内梅罗综合指数法和模糊数学综合评价法对沉积物污染状况进行评价,结果表明:水库中心的S1、S2和S3点为中度或重度污染,其余位于库周的采样点为未污染或轻度污染,总体上库心的沉积物污染比库周严重。结合北大港水库实例,比较3种评价方法的评价结果,得出结论:单因子指数法计算简便,但评价结果偏高;内梅罗综合指数法考虑了沉积物污染评价的综合性,但忽略了评价指标的权重影响;模糊数学综合评价法利用熵值赋权的方法确定指标权重,客观性与综合性较强,评价结果更接近实际情况。

In order to compare the three typical methods of evaluating the sediment pollution, samples of top sediment were collected from eleven sites of Beidagang Reservoir, and indicators of total salt content, organic matter content and the concentrations of total phosphorus and total nitrogen were monitored. Three typical methods including single factor index evaluation method, Nemerow comprehensive index evalua- tion method and fuzzy mathematic comprehensive evaluation method were used to evaluate the status of pollution respectively. The results indicated that the S1, $2 and $3 sites located in the center of the res- ervoir were moderate or severe polluted and the rest of the sites on the edge of the reservoir were non - polluted or lightly polluted. The pollution of sediment in the center was more serious than that on the edge of the reservoir. Taking the Beidagang reservoir as an example, the comparison of the three methods indicates that the single factor index evaluation method was convenient to evaluate but the results are relatively high; the Nemerow comprehensive index evaluation method was a comprehensive method, but it ignored the impacts of the weight of the evaluation indices; the fuzzy mathematic comprehensive evaluation method was an objective and comprehensive method, it calculated the weighting of the index based on the entropy weighting method, and the result was closer to the actual status.