通过实地调查取样和室内分析,研究铜陵矿区周边菜地土壤中重金属(Cu、Zn、Pb、Cd)向两种蔬菜(萝卜和辣椒)可食部分的转移特征。运用5种单一提取剂DTPA、EDTA、HCl、NH4NO3和NH4OAc研究了土壤中重金属的生物有效性,并结合土壤化学性质运用多元逐步线性回归进行对比分析。结果表明,NH4NO3提取态Zn和Cd以及NH4OAc提取态Zn均可以较好地反映重金属的生物有效性;土壤样品中P的含量对Zn和Cu析出有显著影响;与果实类蔬菜相比,根类蔬菜可食部分具有更强的富集重金属能力。土壤-蔬菜间重金属转移系数(TF)均随土壤中重金属含量增加而减小,且TF与土壤提取态金属含量间能建立显著模型,因此用TF来预测蔬菜中金属含量是一种可选的方法。
Soil heavy metal pollution threatens human health mainly via food chain. We investigated the transfer characteristics of heavy metals( Cu, Zn, Pb, Cd) from soils to the edible parts of two vegetable species grown in the vicinity of Tongling mining area, China. Plants and corresponding surface soil samples were collected. Five extraction procedures (DTPA, EDTA, HCl, NHgNO3 and NH4OAc ) were used to measure the bioavailability of soil heavy metals. Stepwise multiple linear regression analysis was used to correlate heavy metal concentrations in soils and plants. It showed that soil Zn extracted by NH4O3 and NH4OAc and soil Cd by NH4NO3 had good correlation with metal concentrations in the edible parts of the vegetables. Soil Pb extracted by all five extractants had no significant correlation with plant Pb concentrations. Soil phosphorus showed a determinant variable in the estimation of extractable Zn and Cu. Root vegetables showed higher accumulation of all metals than fruit vegetables in their edible parts. For all the metals studied, the correlation between the transfer factor(TF) values and extractable metal concentrations in the corresponding soils could be well described by power or exponential models. Therefore, these models may be used to estimate heavy metal accumulation in vegetables.