夏尔西里自然保护区土壤重金属相关性分析及污染风险评价

Risk Evaluation and Correlation Analysis of Soil Heavy Metal Contamination in Xiaerxili Nature Reserve

为了探明夏尔西里自然保护区土壤重金属污染状况及相关性,沿山路蛇形布点采样,根据实地采样数据和试验数据,通过单因子污染指数分析法和潜在生态危害评价法,分别对夏尔西里自然保护区土壤重金属污染状况进行评价分析。结果表明:夏尔西里自然保护区重金属含量超过《土壤环境质量标准(GB15618—1995)》中一级土壤评价标准,Ni,Cr处于清洁状态;土壤中Pb,Zn,Co,Cu超标率分别为65%,50%,60%,85%;土壤中Hg,As超标率分别为90%,100%;8种重金属元素潜在生态危害系数顺序为:Hg>As>Cu>Pb>Co>Ni>Cr>Zn;Zn与Ni、Cu与Pb、Co与Cu的相关性达到显著性水平;Zn与Pb、Cr与Ni、Co与Pb、Co与Zn的相关性达到极显著性水平,元素有较高的同源性,重金属元素含量主要与成土母质有关,人为干扰对重金属元素含量影响较小,Hg,As元素与其他重金属元素相关性低或无相关性。

To explore the status and correlation of soil heavy metal contamination in Xiaerxili nature reserve, the stationing and sampling were carried out in this research following an S-line along the mountain road. Based on field sample data and experimental data, the heavy metal contamination of soil in Xiaerxili nature reserve was evaluated and analyzed through single factor contamination index method and potential ecological risk index method. The result showed that extractable metal contents in Xiaerxili nature reserve exceeded the first-level evaluation standard according to soil environment quality standard （GB15618--1995）. The exceeding standard ratios of Ni, Cr were zero; the exceeding standard ratios of Pb, Zn, Co, Cu were 65%, 50%, 60% and 85%, respectively; the exceeding ratios of Hg and As were 90% and 100%, respectively. The order of potential ecological risk index of the above 8 heavy metal elements is Hg〉As〉Cu〉Pb〉Co〉Ni〉 Cr〉Zn,among which the following pairs of elements were positively correlated： Zn--Ni, Cu Pb, Co--Cu （tested at the 0.05 significant level） ;Zn--Pb, Cr--Ni, Co--Pb, Co--Zn （tested at 0.05 significant level）. These elements shared high homology. Extractable metal contents were mainly connected with the parent material with relatively small human disturbance. There was low or no correlation between Hg and As for any other elements.