Division of Environmental Studies and Sustainable Systems, Kentucky State University, Frankfort, Kentucky 40601-2355, USA.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2012;47(13):1955-65. doi: 10.1080/03601234.2012.676509.
The mobility of heavy metals from soil into the food chain and their subsequent bioaccumulation has increased the attention they receive as major environmental pollutants. The objectives of this investigation were to: i) study the impact of mixing native agricultural soil with municipal sewage sludge (SS) or chicken manure (CM) on yield and quality of cabbage and broccoli, ii) quantify the concentration of seven heavy metals (Cd, Cr, Mo, Cu, Zn, Pb, and Ni) in soil amended with SS or CM, and iii) determine bioavailability of heavy metals to cabbage leaves and broccoli heads at harvest. Analysis of the two soil amendments used in this investigation indicated that Cr, Ni, Cu, Zn, Mo, Cd, Pb, and organic matter content were significantly greater (P < 0.05) in premixed sewage sludge than premixed chicken manure. Total cabbage and broccoli yields obtained from SS and CM mixed soil were both greater than those obtained from no-mulch (bare) soil. Concentration of Ni in cabbage leaves of plants grown in soil amended with CM was low compared to plants grown in no-mulch soil. No significant differences were found in Cd and Pb accumulation between cabbage and broccoli. Concentrations of Ni, Cu, Zn, and Mo were greater in broccoli than cabbage. Total metals and plant available metals were also determined in the native and amended soils. Results indicated that the concentration of heavy metals in soils did not necessary reflect metals available to plants. Regardless of soil amendments, the overall bioaccumulation factor (BAF) of seven heavy metals in cabbage leaves and broccoli heads revealed that cabbage and broccoli were poor accumulators of Cr, Ni, Cu, Cd, and Pb (BAF <1), while BAF values were >1 for Zn and Mo. Elevated Ni and Mo bioaccumulation factor (BAF >1) of cabbage grown in chicken manure mixed soil is a characteristic that would be less favorable when cabbage is grown on sites having high concentrations of these two metals.
重金属从土壤向食物链中的迁移及其随后的生物累积增加了它们作为主要环境污染物的关注度。本研究的目的是：i）研究将本地农业土壤与城市污水污泥（SS）或鸡粪（CM）混合对卷心菜和西兰花产量和质量的影响，ii）量化 SS 或 CM 改良土壤中七种重金属（Cd、Cr、Mo、Cu、Zn、Pb 和 Ni）的浓度，iii）确定重金属在收获时对卷心菜叶片和西兰花头部的生物可利用性。对本研究中使用的两种土壤改良剂的分析表明，Cr、Ni、Cu、Zn、Mo、Cd、Pb 和有机质含量在预混合污水污泥中显著高于预混合鸡粪（P < 0.05）。从 SS 和 CM 混合土壤中获得的总卷心菜和西兰花产量均大于无覆盖（裸露）土壤的产量。与在无覆盖土壤中生长的植物相比，在 CM 改良土壤中生长的植物的卷心菜叶片中 Ni 浓度较低。在卷心菜和西兰花之间，Cd 和 Pb 的积累没有发现显著差异。在西兰花中，Ni、Cu、Zn 和 Mo 的浓度高于卷心菜。还在原生和改良土壤中测定了总金属和植物可利用金属。结果表明，土壤中重金属的浓度不一定反映植物可用的金属。无论土壤改良剂如何，七种重金属在卷心菜叶片和西兰花头部中的总体生物累积因子（BAF）表明，卷心菜和西兰花对 Cr、Ni、Cu、Cd 和 Pb 的累积能力较差（BAF <1），而 Zn 和 Mo 的 BAF 值大于 1。在鸡粪混合土壤中生长的卷心菜中 Ni 和 Mo 的生物累积因子（BAF >1）升高是一个特征，当在这些两种金属浓度较高的地点种植卷心菜时，这将不太有利。
