桂林市菜地土壤和蔬菜铅含量调查与污染评价

从桂林市采集566个蔬菜样品以及相对应的160个菜地土壤样品,同时还采集了背景土壤样品32个,测试其w(Pb),结合GIS制图和数理统计,对土壤铅空间分布特征、土壤和蔬菜中Pb的含量与富集特征进行了分析. 结果表明:桂林市土壤w(Pb)空间差异大,呈西南低、东部和北部高的特点；桂林市菜地土壤w(Pb)的范围、算术平均值和几何平均值分别为10.14～249.00、43.80和38.62 mg/kg,与背景土壤相比,菜地土壤铅积累显著(P为0.001). 蔬菜(以鲜质量计)中w(Pb)范围、中值和几何平均值分别为0.001～1.425、0.050和0.042 mg/kg,综合超标率为6.71%；叶菜类蔬菜w(Pb)显著高于根茎类和瓜果类,甘蓝、萝卜、西红柿和豆类的抗铅污染能力最强,而辣椒和茼蒿的抗铅污染能力则较差；桂林市居民人均通过蔬菜消费摄入铅的量为13.0 μg/d,不存在明显的健康风险. 

Lead Concentrations and Contamination Assessment in Vegetables and Soils in Guilin

A total of 566 vegetable samples and 160 corresponding soil samples, as well as 32 background soil samples, were collected from Guilin to analyze Pb concentrations and their spatial distribution and accumulation characteristics in soils and vegetables. GIS mapping and mathematical statistical techniques were utilized. The results show that there was a large difference in the spatial distribution of lead levels in soils in Guilin. Pb contents in soils in the southeastern part of the city were lower than those in the eastern and northern parts. Soil Pb concentrations ranged from 10.14 to 249.00 mg/kg, with arithmetic and geometric means of 43.80 and 38.62 mg/kg, respectively. Compared with the Pb concentrations in the background soils, there was a significant accumulation of lead in soils where the vegetables were grown. The concentrations of Pb in the edible plant portions ranged (with fresh mass) from 0.001 to 1.425 mg/kg, with median and geometric means of 0.050 and 0.042 mg/kg, respectively. Pb concentrations in 6.71% of the samples were higher than the tolerance limit for lead in the safety requirements for non-environmental pollution in Vegetables. Pb concentrations in the leafy vegetables was significantly higher than that in the melons. Round chili and Chrysanthemum coronariumhad the highest BCFs, while Pb BCFs in cabbage (Brassica oleracea), radishes, tomatoes and beans were relatively lower. The average absorption rate of Pb from vegetables was 13.0 μg/d for people of Guilin, which will not cause significant health risk to the local residents.