东南植烟区不同类型农区大气金属元素沉降通量差异分析

Different deposition fluxes of atmospheric metals among tobacco-planting regions in southeast China

为明确我国东南烟草种植区大气金属元素沉降通量及其在不同农区间的差异,采用野外自然沉降法收集大气降尘样品,分析了Al、Cr、Mn、Fe、Ni、As、Se、Cd和Pb等9种金属元素的沉降通量,并比较各元素在一般农区、城镇周边、道路两侧和工厂周边等4种类型农区间的差异。结果表明:(1)金属元素沉降通量数值差异显著,其中Al的沉降通量在83.91~15 132.88μg·m^(-2)·d^(-1)范围内,而Se的沉降通量仅在0.05~2.68μg·m^(-2)·d^(-1)之间;沉降通量的变异系数也存在较大差异,其中以Mn、Fe和Al的变异系数较大,As和Pb的变异系数较小。(2)在4种类型农区中金属元素沉降通量排序均依次为Al>>Fe>>Mn>>Pb>其余5种元素,Cr、Ni、As、Se和Cd5种金属元素沉降通量因农区不同而存在差异;Pb沉降通量大于Cr、Ni、As、Se和Cd 5种金属元素,大气Pb沉降可能是除土壤和肥料外烟草中Pb的另一重要来源。(3)9种金属元素的平均沉降通量均以工厂周边最大,且与一般农区、城镇周边、道路两侧等3种类型农区间存在显著差异,一般农区、城镇周边、道路两侧之间金属元素沉降通量间差异均不显著。

To investigate the deposition fluxes of atmospheric metals and their differences among various southeast tobacco-planting regions,natural precipitation method was adopted to collect atmospheric deposition samples. The deposition fluxes of nine metals（Al,Cr,Mn,Fe,Ni,As,Se,Cd and Pb） and the differences of nine metals among four types of farming areas（general agricultural area,area around town,area close to roadside and area around factories） were analyzed. The results showed that：1） The deposition fluxes of nine metals were significantly different,and those of Al and Se were 83.91-15 132.88 and 0.05-2.68 μg · m^（-2）· d^（-1）,respectively. The variation coefficients of deposition fluxes of different metals also varied greatly,those of Mn,Fe and Al were higher,and those of As and Pb were lower. 2） The deposition fluxes of the nine metals from the four farming areas were in the order of Al Fe Mn Pb the other five metals（Cr,Ni,As,Se and Cd）,and the deposition fluxes of Cr,Ni,As,Se and Cd differed among the four types of farming areas. The deposition flux of Pb was higher than those of Cr,Ni,As,Se and Cd,hence atmospheric Pb deposition might be an important source of Pb in tobacco leaves in addition to soil and fertilizer. 3）The deposition fluxes of the nine metals in areas around factories were the highest and significantly differed from those in general agricultural area,areas around town and areas close to roadside,while the differences among the last three farming areas were not obvious.