典型医药企业聚集区土壤重金属污染特征及成因分析

Characteristics and causes of soil heavy metal pollution in typical pharmaceutical enterprise gathering areas

为探究湖北省某地典型医药化工企业腾退地块土壤污染状况及对周边环境介质的影响并量化土壤重金属的来源贡献,系统采集地块内及其农田影响区的土壤样品592个、水稻样品23个、河流沉积物样品11个,测定了As、Cd、Cu、Pb、Hg、Ni等重金属含量,分别运用地累积指数法、生态风险评估法、土壤污染风险评价法分析了地块内及其周边农田土壤重金属的污染特征,并探究了土壤重金属来源.结果表明,医药企业地块内土壤中重金属含量均值显著高于周边农田土壤,土壤重金属As地累计指数最高,是地块内土壤生态风险的主要污染元素,最大污染深度达4.5 m.地块周边农田土壤重金属As、Cd、Pb、Hg超过标准筛选值,水稻重金属含量未超食品安全标准限值.地块内重金属主要来源于历史生产企业生产活动,地块内地表径流对其周边河流水质造成了影响,河流作为周边农田的灌溉水,长期的灌溉活动和可能的淤泥回填已经对农田土壤环境安全产生了威胁.医药企业聚集区及其影响区的重金属源汇关系应得到重视,相关部门应针对不同介质和区域的污染现状加强重金属的污染防治和风险管理,并对企业聚集区腾退地块土壤污染进行源头管控.

The purpose of this paper is to investigate the status of soil pollution and its impact on the surrounding environmental media in a typical pharmaceutical and chemical enterprise vacated site in Hubei Province and to quantify the source contribution of soil heavy metals.In this paper,592 soil samples,23 rice samples and 11 river sediment samples were systematically collected from the plot and its farmland impact area,and the heavy metal contents of As,Cd,Cu,Pb,Hg and Ni were determined.This paper analyzed the pollution characteristics of soil heavy metals in the plot and its surrounding farmland and explored the sources of soil heavy metals by using the ground accumulation index method,ecological risk assessment method and soil pollution risk evaluation method,respectively.The results showed that the average value of heavy metal content in the soil of the pharmaceutical enterprise plot was significantly higher than that of the surrounding farmland soil.The cumulative index of soil heavy metal As land was the highest.It is the main contaminant element of soil ecological risk in the plot.The maximum contamination depth reached 4.5 m.The heavy metals As,Cd,Pb and Hg in the farmland soil around the plot exceeded the standard screening values.The heavy metal content of rice did not exceed the limit of food safety standards.The heavy metals within the plot mainly originated from the production activities of historical production enterprises.Surface runoff within the parcel has impacted the water quality of its surrounding rivers.Water as the irrigation water of the surrounding farmland,the long-term irrigation activities and possible silt backfill have threatened the soil environmental safety of the farmland.The source-sink relationship of heavy metals in the pharmaceutical enterprises gathering area and its influence area should be paid attention.Relevant departments should strengthen the pollution prevention and risk management of heavy metals for different media and pollution status of the region.Relevant departments should also control the source of soil pollution in the vacated land of the enterprise gathering area.