沙漠涉煤工业园及周边土壤重金属富集特征、潜在生态风险及来源解析

Enrichment characteristics, potential ecological risks and source apportionment of heavy metals in desert coal-related industrial parks and surrounding soils

关键词:  涉煤工业园  沙漠  土壤重金属  空间分布  潜在生态风险

Key words:  coal related industrial park  desert  soil heavy metal  spatial distribution  potential ecological risk

摘要:

文章以中国国家级能源化工基地的M核心园区为对象，在分析4类功能区 （工业区、荒地区、农田区、居民区）土壤重金属富集状况与分布特征的基础上，进一步对园区及其周边土壤重金属的污染特征进行测定，对潜在生态风险及来源进行评价及解析。结果显示：所测定的8种重金属元素中（Cd、Cr、 Pb、As、Cu、Zn、Ni和Mn），研究区Cd元素超标最为严重，在空间分布上，8种重金属呈现出北部高于南部、西部高于东部的趋势；4类功能区的土壤重金属含量存在显著差异，大多数土壤重金属含量整体呈居民区＞荒地区＞工业区＞农田区。其中，Cd在污染指数评价法中达到较高的污染水平。上述结果表明，沙漠涉煤工业园及其周边地区的土壤重金属已然导致了显著的生态风险，在强化监测防控的同时， 也应介入必要的治理。

Abstract:

Background, aim, and scope The ecological environment in the desert area is fragile, and industrial activities are easy to cause pollutant enrichment, resulting in higher ecological risks. In recent years, heavy metal pollution in industrial parks in desert areas has gradually drawn people’s attention. Therefore, this paper aims to evaluate the enrichment status and pollution risk of heavy metals in M Industrial Park in desert areas. In order to provide data support for the management of industrial activities in fragile ecological environment areas, such as desert areas, and provide theoretical support for the planning and management of industrial activities. Materials and methods In this paper, the core park of China’s national energy and chemical base was the research object, and the enrichment and distribution characteristics of eight kinds of soil heavy metals (Cd, Cr, Pb, As, Cu, Zn, Ni and Mn) in four functional areas (industrial area, wasteland area, farmland area and residential area). Results (1) The Cd exceeds the standard most seriously in the study area, followed by As and Cu, and the average content of the remaining elements does not reach the soil background value in Shaanxi Province. (2) In terms of spatial distribution, the eight heavy metals show a trend that the northern part is higher than the southern part, and the western part is higher than the eastern part. The heavily polluted sample sites are mainly distributed in industrial and residential areas. There are significant differences in the soil heavy metal contents of the four functional areas, with most of the soil heavy metal contents showing an overall trend of residential area＞ wasteland area＞industrial area＞farmland area. (3) The Nemero comprehensive pollution index shows that the study area reaches heavy pollution, while for single elements, Cd reaches heavy pollution and As are moderate; the results based on potential ecological risk evaluation also show that Cd reaches strong ecological risk, while the mean value of comprehensive potential ecological risk coefficient of the whole study area is 168.42, which is a slight ecological risk level, but the difference between sample points is obvious. About half of these sample sites show moderate ecological risk in terms of potential ecological risk index (RI). (4) The heavy metal pollution in the surface soil of the study area mainly comes from three sources: Cr, Ni, Cu, Mn elements are soil parent material sources, Pb and Zn elements are traffic sources, and As and Cd are industrial sources. Discussion The results indicate that there are some heavy metal elements in the study area with concentrations higher than the standard value, among which Cd exceeds the standard most severely, which is related to the unfavorable soil texture for heavy metal enrichment in desert areas. The research results indicate that the heavy metal content in most of the study area is below the standard value. Cd contamination stands out as the primary issue. Its distribution is associated with soil properties, which hinder the accumulation of heavy metals. The pollution of residential and industrial areas in different functional areas is the most serious. This is because the residential area is located in the middle of the two main traffic arteries, which is adjacent to the coal chemical enterprises in the functional division, and is greatly affected by industrial activities and traffic. In recent years, the continuous expansion of industrial parks has led to an increase in the enrichment level of heavy metals in surrounding areas. For example, the accumulation of garbage in barren areas leads to higher pollution levels, and heavy metals in the park are mainly caused by industrial activities. Conclusions Among the eight heavy metal elements measured, Cd exceeded the standard the most severely in the study area. In terms of spatial distribution, the concentrations of these 8 heavy metal elements showed a trend of being higher in the north than in the south and higher in the west than in the east. There are significant differences in soil heavy metal content among the four functional areas, with most soils having the highest overall heavy metal content in residential areas and the lowest in agricultural areas. Recommendations and perspectives The above results indicate that the soil heavy metals in the desert coal-related industrial park and its surrounding areas pose a significant ecological risk, and necessary treatment should be implemented while strengthening monitoring and prevention.