典型电子拆解地两种指示生物监测重金属污染的对比研究

Comparative study of two bioindicators in the monitoring of heavy metals pollution in e-waste dismantling areas

利用ICP-MS定量测定了温岭市电子垃圾拆解地区的大灰藓及樟树叶中的12种金属元素的含量,对比分析了两种指示生物对不同金属元素的富集情况.结果显示,不同地区样品中的所有金属含量呈现污染区>对照区的趋势,其中苔藓中As、Cr、Mn、Se、V和Cd,樟树叶中Cr、Cu、Ni、Se、Sb和Cd的含量呈现重污染区>轻度污染区>对照区的趋势.拆解区中樟树叶中除Mn以外的金属总含量(所有金属含量之和)要低于苔藓.除Mn、Cr和Se以外的其它9种金属在苔藓中的含量要显著高于樟树叶中的金属含量(p<0.05),但苔藓中金属含量的标准偏差要大于樟树叶.由污染因子(pollution factor)的结果表明苔藓及树叶样品中的金属Sn、Sb及Cd的污染因子最高;另外,研究通过比较树叶样品的不同预处理过程对最终含量测定的影响,发现经超纯水清洗的树叶样品中所有金属浓度要明显低于未经清洗的样品,并且标准偏差较低,数值稳定性好.主成分分析结果表明,Co、Cr、Ni、Pb、Sn及Cd为密切相关的一类元素,主要来源于电子废弃物拆解行为,而Mn、As及Se为第二类元素,主要来源于地质因素.

12 metals （As, Co, Cr, Mn, Cu, Ni, Pb, Se, V, Sn, Sb and Cd） in Hypnum plumaeforme wils and camphor tree leaves collected from informal e-waste region in Wenling were determined by ICP-MS to compare the specialized enrichment ability of the two bioindicators. The results showed that concentrations of all metals in the polluted area were higher than those in the control area. Concentrations of As, Cr, Mn, Se, V and Cd in mosses and concentrations of Cr, Cu, Ni, So, Sb and Cd in tree leaves presented the trend： heavy polluted area〉 mild polluted area〉 control area. The total concentrations of metals in dismantling areas were lower in camphor tree leaves except Mn. The concentrations of As, Co, Cu, Ni, Pb, V, Sn, Sb and Cd were significantly higher in mosses than those in leaves （p〈0.05）. However, the standard deviation of metal concentrations in leaves were obviously lower than those in mosses. According to the calculated results, PF values of Sn, Sb and Cd were the highest in samples. In addition, the impacts on the determined concentrations conducted by different pretreatment methods were evaluated with and without rinse by ultra water. It was found that the concentrations of all metals were significantly higher in rinsed samples by ultra water, and showed better stability in these samples according to lower standard deviation. Factor and correlation analysis showed that Co, Cr, Ni, Pb, Sn and Cd were in the first group derived from e-waste processing behavior, while Mn, As and Se in the second group were more likely from crust.