渭干河-库车河绿洲土壤重金属分布特征与生态风险评价

发布时间：2018-11-08 12:50

【摘要】：随着工业发展和城市化进程的加剧,农用化学物质种类和数量不断增加,导致土壤受到不同程度的重金属污染,农田土壤重金属污染尤为严重。该文以新疆最典型的荒漠绿洲渭库绿洲为研究区,采集土壤样本57个,测定出土壤样本中砷(As)、汞(Hg)、铅(Pb)、铬(Cr)、锌(Zn)和铜(Cu)6种元素的含量,分别采用地统计空间分析法、地积累指数法(I_(geo))和潜在生态风险指数(RI)等方法,对研究区土壤重金属污染和潜在生态风险程度做出科学评价,并采用多因子分析方法对重金属的来源进行了讨论。1)研究区Hg、As、Cu、Cr、Pb和Zn 6种土壤重金属平均质量分数分别为2.41、0、37.64、25.25、39.78、15.01 mg/kg,平均含量均未超过国家二级标准,其中Pb的平均含量超过了新疆土壤重金属背景值,存在一定程度的重金属积累;2)由地积累指数法(I_(geo))和潜在生态风险指数(RI)分析得出,研究区土壤重金属的I_(geo)均值As(-4.59)Hg(-3.62)Cu(-1.92)Cr(-1.44)Zn(0.59)Pb(0.73),RI均值为22.26,整体上属于无污染水平,说明研究区域土壤重金属环境质量总体优良;3)通过综合相关性分析、主成分分析和聚类分析,研究区重金属的来源可以分为两类,Cu、Zn、Cr和Pb来源于成土母质等自然背景和人类农业生产活动;As和Hg来源于研究区域地形地貌、水文环境等自然背景。4)分析研究区域综合生态风险指数RI可知,研究区整体处于无污染水平,但各分区RI指数存在差异,其中西北部(NW)和东北部(NE)分区RI值相对较高,最高值出现在东北部(NE)分区上。该研究提出的分析方法能快速、客观反映绿洲土壤重金属污染特征以及来源,可为绿洲土壤环境质量评价和管理提供依科学依据。
[Abstract]:With the development of industry and the process of urbanization, the kinds and quantities of agricultural chemicals are increasing, which results in the soil being polluted by heavy metals to varying degrees, especially the heavy metal pollution in farmland soil. In this paper, 57 soil samples were collected from Weiku oasis, the most typical desert oasis in Xinjiang, and the contents of six elements of arsenic, (As), mercury, lead, chromium, (Cr), zinc, (Zn) and copper (Cu) in soil samples were determined. The soil heavy metal pollution and potential ecological risk degree in the study area were evaluated by the methods of geostatistical spatial analysis, land accumulation index (I _ (geo) and potential ecological risk index (RI), respectively. The sources of heavy metals were discussed by multifactor analysis. 1) the average mass fraction of heavy metals in six soils of Hg,As,Cu,Cr,Pb and Zn were 2.41%, 37.64%, 25.25% and 39.78 mg/kg, respectively. The average content of Pb was not higher than that of the national secondary standard, and the average content of Pb exceeded the background value of heavy metals in Xinjiang, and there was a certain degree of accumulation of heavy metals. 2) based on the analysis of land accumulation index (I _ (geo) and potential ecological risk index (RI), The I _ (geo) mean As (-4.59) Hg (-3.62) Cu (-1.92) Cr (-1.44) Zn (0.59) Pb (0.73), RI) of soil heavy metals in the study area was 22.26. The results showed that the environmental quality of heavy metals in soil of the study area was excellent in general. 3) through comprehensive correlation analysis, principal component analysis and cluster analysis, the sources of heavy metals in the study area can be divided into two categories: Cu,Zn,Cr and Pb derived from natural background such as soil-forming parent material and human agricultural production activities; As and Hg come from the natural background of regional topography and hydrological environment. 4) the comprehensive ecological risk index RI shows that the whole area is in the level of no pollution, but there are differences in RI index among different regions. The values of RI in the northwest (NW) and the northeast (NE) are relatively high, and the highest RI values are found in the northeastern (NE). The analytical method proposed in this study can reflect the characteristics and sources of heavy metal pollution in oasis soil objectively and provide scientific basis for the evaluation and management of soil environmental quality in oasis.
【作者单位】：新疆大学资源与环境科学学院;新疆大学绿洲生态教育部重点实验室;新疆智慧城市与环境建模普通高校重点实验室;
【基金】：国家自然科学基金项目(41361016,40901163,41761077) 新疆大学博士启动基金(BS120116,No.XY110117) 新疆维吾尔科技厅基金(2014KL005,2013711014)
【分类号】：X53;X826

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