贵州五马河流域土壤养分和重金属含量与空间分布

为给五马河流域土地资源可持续利用及生态环境保护提供参考,以五马河流域中三元村为研究对象。通过野外调查和实验分析,利用相关评价方法结合地理信息技术(geographic information system,GIS),采用反距离权重(inverse distance weighting,IDW)插值分别对土壤中养分及重金属空间分布特征、含量水平及重金属生态风险进行分析,结果表明:(1)土壤中全氮(TN)、全磷(TP)、有机质(SOM)总体含量较丰富,全钾(TK)非常缺乏。土壤养分空间分布TN和SOM含量北部高于南部,TP和TK含量南部高于北部; TN含量最低分布在西南、SOM和TK在中部、TP在东北;(2)Hg、Ni、Cu和Zn平均值高于贵州省背景值,Cd高出背景值和中国土壤污染风险筛选值,存在污染现象,Cr和As为清洁;重金属空间分布Cd、Cr、Hg、As和Zn含量北部高于南部,Ni和Cu含量南部高于北部; Zn含量最高分布在东北、Cu和Ni分布在中部少部分区域,Cd、Cr、Hg和As分布在西北;其中西北存在Cd污染,中部和西南少部分区域存在Cu污染,东北存在Zn污染;(3)部分采样点Cd、Hg已存在潜在生态风险,Cr、Ni、As、Cu和Zn为轻微潜在生态风险; 25%采样点重金属综合潜在生态危害为中度风险,其余为低风险。

Contents and Spatial Distribution of Soil Nutrients and Heavy Metal in Wuma River Basin of Guizhou

In order to provide reference for the sustainable utilization of land resources and the protection of ecological environment in the Wuma river basin, as the Sanyuan village for the research object in the wuma river basin. Through field investigation and experimental analysis, the content of nutrients and heavy metals in soil was evaluated by using some evaluation criteria, the spatial distribution of nutrients and heavy metals in soil was analyzed by Inverse Distance Weight (IDW) interpolation method, and the ecological risk assessment of heavy metals was conducted by Potential Ecological Risk Index Method. The results showed that :(1) The total contents of TN (total nitrogen), TP (total phosphorus) and SOM (organic matter) were abundant in soil, while TK (total potassium) was scarce. The high-value region of TN and SOM is mainly in the northwest, while the low-value region of TP is mainly in the northeast, with the highest content in the southwest and higher in the south of TK. (2) The overall content of Hg, Ni, Cu and Zn is higher than the background value of Guizhou province, and Cd is higher than the background value and the national soil pollution risk screening value, it exists Pollution; Cr and As are relatively clean. The heavy metals are in the northwest (Cd, As, Hg) or the Midwest (Ni and Cu), except for the high Cr region in the north and Zn in the northeast. (3) Hg in soil has reached a relatively strong potential ecological risk, Cd, Cr, Ni, As, Cu and Zn are all slight potential ecological risks, and the comprehensive potential ecological harm of 7 heavy metals is at a low risk level.