某废弃铅冶炼企业周边土壤和蔬菜的铅含量及分布特征

为了解并掌握废弃铅冶炼企业对周边环境的影响程度及范围,在湖北某废弃铅冶炼企业周边按照扇形布点法采集表层土壤样品102个、蔬菜样品69个,分别采用石墨炉原子吸收分光光度法和电感耦合等离子体原子发射光谱法检测样品铅含量,分析土壤环境和蔬菜样品铅含量的空间分布。结果表明,废弃铅冶炼企业周边土壤铅含量的几何均数为39.8 mg·kg~(-1),高于湖北省土壤背景值(26.7 mg·kg~(-1))。土壤铅的地质累积指数平均值为0.09,其中,36.4%的土壤采样点地质累积指数大于0。距离废弃铅冶炼企业500、1 000 m和1 500 m采样点的地质累积指数平均值分别为2.11、0.61和0.33,而2 000 m及其以外土壤铅的地质累积指数平均值均小于0。白菜、萝卜和葱铅含量的超标率分别为24.0%、36.0%和6.3%,其内梅罗综合指数分别为8.12、4.38和1.26。废弃铅冶炼企业周边土壤和蔬菜在500 m范围内污染最为严重,土壤在500~2 000 m之间呈轻度或中度污染;白菜、萝卜和葱受到铅污染的最大影响距离分别在500~1 000、1 000~1 500 m和500~1 000 m之间,其分别呈现重度、重度和轻度污染,且在企业周边呈现明显的污染和富集特征。

Lead Contents and Distribution Characteristics of Soils and Vegetables Around an Abandoned Lead Smeltery

In order to disclose the degree and scope of lead pollution of the abandoned lead smeltery, 102 surface soil samples and 69 vegeta-bles samples were collected by using the method of fan-shaped sampling points around an abandoned lead smeltery in Hubei Province. The lead contents of soils and vegetables were detected by graphite furnace atomic absorption spectrometry and inductively coupled plasma atom-ic emission spectrometry, respectively, and the lead spatial distribution was analyzed. The results showed that the geometric mean of lead con-tents in soils around the abandoned lead smeltery was 39.8 mg·kg-1 and exceeded the soil background value of Hubei Province(26.7 mg·kg-1). The mean value of geo-accumulation indexes of lead contents in soil was 0.09, and 36.4%of them exceeded zero. The geo-accumulation in-dexes of sampling distance of 500, 1 000 m and 1 500 m from the smeltery were 2.11, 0.61 and 0.33, respectively, while the values of sam-pling distances of more than 2 000 m were all less than zero. 24.0%、36.0%and 6.3%of the lead contents exceeded the standard value of limited standards of contaminants in vagetables for cabbage, radish and green onion samples, respectively. The soils and vegetables around the abandonded lead smeltery within 500 m were contaminated seriously. The degree of lead pollution in soils was mild or moderate within 500 m to 2 000 m, and the maximum scope in cabbage, radish and green onion was polluted within 500~1 000, 1 000~1 500 m and 500~1 000 m, respectively. Lead pollution in vegetables around the abandonded lead smeltery presented obvious characteristics of high pol-lution and enrichment.