理想点法在太原盆地土壤重金属污染等级评价中的应用

根据重金属元素污染等级评价标准，利用理想点法对太原盆地土壤重金属进行了污染等级评价。评价采用2种方式，一种是将分级标准中的参考值列入评价标准，作为污染等级最大的一级标准处理；另一种是不考虑参考值，仅考虑分级标准中一级～五级的评价标准值。用方式一进行评价得到的结果使太原盆地整体污染情况均有削弱，而方式二能较好地区分开各区污染程度高低，更能够具体地反映污染的实际情况，不容易造成污染信息的损失。评价结果表明，污染程度较低的点集中在边远山区，污染程度较高的点集中分布在汾河流域。从城市分布方面来看，太原市、榆次市、汾阳—孝义一带污染较为严重，太谷、祁县次之，清徐、交城、文水、平遥的土壤环境相对清洁。

THE APPLICATION OF THE IDEAL POINT METHOD TO THE GRADE EVALUATION OF HEAVY METAL POLLUTION IN SOILS OF TAIYUAN BASIN

According to the grade evaluation criteria of heavy metal pollution, the authors carried out the pollution grade evaluation for soil heavy metals in Taiyuan basin using the ideal point method. Two means were chosen for the evaluation: one includes the reference value of the grade standard in the evaluation criteria as the biggest level of the pollution grade, and the other only considers the 1st ~ 5th level of the evaluation standard value, with no consideration given to the reference value. It is shown that the first means weakens the whole pollution situation of Taiyuan basin, whereas the second means can separate pollution degrees of various areas preferably and reflect the pollution situation specifically, thus fairly satisfactorily preserving the pollution information. The evaluation results indicate that the points of relatively low pollution degrees are concentrated in mountain areas, while the points of rather high pollution degrees are distributed along the Fenhe River valley. As for urban pollution, Taiyuan, Yuci and Fenyang-Xiaoyi areas are subjected to rather heavy pollution, Taigu and Qixian possess the second place, and the soil environment of Qingxu, Jiaocheng, Wenshui and Pingyao is comparatively clean.