关键词: 叶面降尘, 茶区, 颗粒组成, 重金属

Abstract: 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.

Key words: foliar dust, tea production area, particulate composition, heavy metals