下曼来铁矿区周边土壤重金属污染分析与评价

Analysis and Evaluation of Heavy Metal Pollution in Soil around Xiamanlai Iron Ore Area

为探究下曼来露天的铁矿开采对周边土壤的影响,本文对采矿区周边进行了不同距离、不同方位的采样研究,共采集64处表层土壤样品,对其重金属含量进行测定。采用成图法、单因子指数法和内梅洛综合指数法对测得数据进行分析。采用成图法分析重金属来源和分布情况,采用单因子指数法分别对土壤重金属元素距矿区中心的不同方位和距离进行污染指数评价,采用内梅罗综合指数法对该地的重金属污染进行综合分析,得到综合污染评价。结果表明:重金属污染元素主要由Zn、Pb元素组成。其中,Pb的污染范围最广,污染程度较大。Cu元素分布与山体高度、降雨量相关。Zn元素分布与采矿区的距离和气候相关。Co元素含量分布与采矿活动相关。Ni元素分布与矿区活动和植被覆盖相关。Cr、Pb元素因矿区活动而在一定范围内富集。按内梅罗综合指数法评价,根据距离划分,其中800 m范围内皆为轻度污染。根据方位划分,各方向皆为轻度污染。

In order to investigate the impact of iron ore mining on the surrounding soils in the Xiamanlai open pit, this paper collected sampling research at different distances and orientations around the mining area. A total of 64 surface soil samples were collected and their heavy metal contents were determined. The measured data were analyzed by the mapping method, the single-factor index method and the Nemelo composite index method. The mapping method was used to ana-lyze the sources and distribution of heavy metals. The single-factor index method was used to evaluate the pollution index of soil heavy metal elements at different orientations and distances from the center of the mine, respectively. The comprehensive pollution evaluation was obtained by the comprehensive analysis of the heavy metal pollution at the site using the Nemero comprehensive index method. The results showed that the heavy metal pollution elements mainly consisted of Zn and Pb elements. Among them, Pb has the widest pollution range and the greater pollution degree. The distribution of Cu elements is related to the height of the mountain and rainfall. The distribution of Zn elements is related to the distance of the mining area and the climate. The distribution of Co elements is related to the mining activities. The distribution of Ni elements is related to the mining activities and the vegetation cover. The Cr and Pb elements are enriched in a certain range due to the mining activities. According to the evaluation of the Nemero composite index method, according to the division of distance, all of them are lightly polluted within 800 m. According to the division of orientation, all directions are lightly polluted.