甘肃省白银市中心区土壤环境质量评价

甘肃省白银市是中国重要的有色金属基地之一，是干旱地区受重金属污染的典型地区，土壤具有污灌的历史．为弄清该地区土壤中重金属污染的程度和空间分布，文章根据野外调查采样与室内分析，选取重金属镉、铅、镍、铜、锌５种元素的有效态含量作评价参数，采用模糊聚类与模式识别方法，进行土壤环境质量评价．评价结果将全区划分为三类：清洁类；轻污染类；严重污染类，指出各类型的污染特征，为控制污染、改善环境质量提供科学依据．

Assessment on the Soil Environmental Quality in the Central District of Baiyin City,Gansu Province

The city of Baiyin is located in the northwestern part of Aoess Plateati.It belongs to the semi-arid region. It is one Of the important nonferous mining and smelting industrcal bases in China, It is alsoatypical district where soil has been polluted by heavy metal, and agricultural land has been irrigatedwith industrial and living wastewater for more than a decade. In order to make a thorough investigation of heavy metal polluting degree and its space range,thepaper applies the soil environmental critical levels as the evaluating standards,chooses the available con-tent of five heavv metal clements(Cd,Pb,Ni ,Cu ,Zn)as evaluating factors in the light of the results ofoutdoor investigation and indoor analysis, and uses the method of fuzzy cluster and model distinguish tomake an assessment on the soil environmental quality,and divide the soil environmental quality intothree classes:1)unpolluted; 2)light polluted;3) heavy polluted,At last,the paper make a discussion ofthe assessment.