为了解茶区大气降尘物中的重金属状况,以浙江省某市为例,分别收集了城市、工矿、公路、农居点附近和清洁区等不同区域茶叶叶面降尘,采用激光粒径分析仪测定了叶面降尘的粒径分布,应用ICP-AES测定了叶面降尘中的重金属含量,并探讨了茶区叶面降尘中重金属的可能来源。结果表明,茶区叶面降尘中颗粒物粒径集中分布在100 µm以下,粒径累积曲线呈正态单峰分布;平均粒径大小：清洁区<农居点附近<城市附近<公路附近<工矿附近。茶区叶面降尘中Cd、Pb、Ni、Cu、Zn和Hg有明显的富集,其质量分数范围分别为1.76~11.34、87~648、36~154、133~476、165~1121、0.36~4.23 mg/kg。不同茶区叶面降尘中重金属含量差异显著,多数重金属元素的含量以工矿附近茶园降尘中的最高,其次为城市和公路附近,清洁区的最低。研究认为,茶区降尘中Cd、Pb、Cu、Zn和Hg主要来源于人为污染,而Cr、Co、Ni、Al、Fe和Mn主要为自然起源。

To understand the concentrations of heavy metals in foliar dust in tea production areas, tea foliar dust samples were collected from five different tea production areas, including nearby urban, nearby mining, nearby highway, nearby village and a clean area without any pollution source. Size distribution of the dust samples was determined with a laser particle sizer, and total concentrations of heavy metals in the samples were determined with ICP-AES. The possible sources of the heavy metals in the dust were also discussed. It was found that the particulate size was distributed symmetrically with a range less than 1 mm. More than 76.52% of the dust was below 100 µm. Mean size of the dust increased in the sequence of a clean area < nearby village < nearby urban < nearby highway < nearby mining. Cd, Pb, Ni, Cu, Zn, and Hg were significantly enriched in the tea foliar dust, and concentrations of the metals ranged from 1.76 to 11.34 mg/kg for Cd, 87 to 648 mg/kg for Pb, 36 to154 mg/kg for Ni, 133 to 476 mg/kg for Cu, 165 to 1121 mg/kg for Zn, and 0.36 to 4.23 mg/kg for Hg, respectively. The concentrations varied with sampling areas, and were highest in the nearby mining, and lowest in the clean area. Both correlation analysis and principal component analysis suggested that Cd, Pb, Cu, Zn, and Hg in the dust were originated from industrial pollution, vehicle emission, and other anthropogenic sources, and Cr, Co, Ni, Al, Fe, and Mn could be attributed to natural sources.