福州市公园灰尘磁学特征及其环境意义

以福州市公园灰尘为研究对象,对其进行了磁学参数特征研究,结果表明,福州市公园灰尘χ、χfd%、SIRM、S-ratio、SIRM/χ平均值分别为269.80×10-8m3/kg、0.73、6175.07×10-5(A?m2)/kg、0.91、30.82A/m.综合分析发现,福州市公园灰尘磁性矿物含量较高,部分样品的主要磁性矿物为铁磁性矿物,部分样品为反铁磁性矿物,且Day图反映了其磁性矿物粒径主要以单畴(SD)和假单畴(PSD)为主,这些均受控于交通、城市建设等人类活动的干扰、由西向东倾斜的地形条件和夏季台风的滞留效应的影响;福州市二环内外受不同的城市化过程中人类活动、土地利用格局、季风等影响,其磁学参数特征所表征的环境意义不同;福州市公园灰尘磁学特征(χ、χfd%、IRM及其组合参数、磁滞回线)可以作为福州市城市污染物监测的一种重要的替代指标.

Magnetic properties of dust in Fuzhou parks and their environmental significance

To effectively monitor environmental pollution in Fuzhou city, magnetic properties of dust from different parks were detected. Results show that the mean value of χ, χ_fd%、SIRM、S-ratio and SIRM/χ were 269.80×10^-8 m³/kg, 0.73, 6175.07×10^-5(A×m²)/kg, 0.91 and 30.82A/m, respectively. The primary magnetic minerals of dust samples were identified to be ferromagnetic minerals (magnetite and maghemite), even hematite was found in some samples, in the single domain (SD) and pseudo-single domain (PSD) grain size in Day-plot. Magnetic concentration and grain sizes of dust in Fuzhou parks were controlled by anthropogenic activities, e.g. traffic and city construction, landform and typhoon, especially the area around second ring road. Results demonstrate that details measurements of magnetic properties can serve as an efficient complementary tool for monitoring environmental pollution in Fuzhou.