Speciation of major heavy metals in ambient fine particles collected in the atmospheres of Xuanwei, Yunan, a higher lung incidence area in China

Abstract

Xuan Wei area, Yunnan province of China, has one of the highest lung cancer mortality rates in China. Heavy metals in the aerosol are potential facts that might attribute to the cause of lung cancer, and speciation of heavy metals could play a key role in toxicity of heavy metals. Therefore, we try to reveal speciation of major heavy metals by using of synchrotron radiation techniques in this study. Mass concentration of chemical elements in ambient particles were analyzed by PIXE (Proton induced X-ray emission), and speciation of Cu was investigated by XAFS (X-ray absorption near-edge structure). Our results demonstrated that mass levels of heavy metals ranked as Fe (791.62 ng/m3) >Zn (479.49 ng/m3) >Pb(154.76 ng/m3) >Cu(28.51 ng/m3) >Co (11.79 ng/m3) >Ni (8.20 ng/m3). The Cu speciation in the different size fraction was different. Speciation of Cu in fine particles (PM0.56~0.32) is present as Cu (I), and significant amount of Cu is present as Cu (II) in the ultrafine particles (PM0.1).