The Research On Speciation And Pollution Of Heavy Metals In TSP Of Changsha

The TSP samlpes being sampled in summer and autumn respectively of Changsha by the TH-150C middle volume total suspended particulates (TSP) samplers were used to analyse the particulate concentrations by the weight method and the speciation analysis of heavy metal element of TSP were carried out using the BCR and Tessier speciation method. The results show that the atmospheric particulate pollution is serious hvaing a average concentration value of 220.7±42μg/m3, more than the national secondary standard (200μg/m3), but none of the four sampling sites exceeding the national thirdary standard (300μg/m3). The concentration of TSP is in the order of:Jinkai>Kaifu> Gaokai> MaPoling and that of heavy metals is:Zn> Pb> Cu> Mn> Cd. The total concentration of heavy metals in different spots is in the order of:Jinkai> Ma Poling> Gaokai> Kaifu, showing that the concentration of TSP has little relationship with that of heavy metal. In four sites, the speciation of heavy metals is similar, but in content is quite different. Pollution factor calculation results show that the metal migration size:Cd> Cu> Zn> Mn> Pb; factor analysis results show that the five kinds of heavy metals are from human activities and in the three main factors causing the total rate of 85%. Air particle pollution is more serious in autumn of Changsha and the concentration of TSP exceeds the average concentration of atmospheric environmental quality standard 2 (200μg/m3) at Yuhua District and the railway station, but none of the three sampling points over the average concentration of thirdary standard; and particles have high content of heavy metals, the concentrations of Zn and Pb were larger than those of Cu and Cd, with the average concentration of Zn was 2.528μg/m3, Pb was 2.347μg/m3, Cu was 0.187μg/m3 and Cd was 0.002μg/m3.According to the results of chemical speciation analysis, Cu has the highest content of bioavailable state while Zn, Pb, Cd have lower levels of bioavailable state, and except Pb and Zn of the railway station, all of these are over 50%. The order of comparative mobility and bioavailability of heavy metals is: Cu>Cd>Zn>Pb. It is also analyzed the microstructure of TSP by scanning electron microscope and its supporting spectrum analyzer. Research shows that:silicon aluminum acid salt particles are the main ingredients coming from the source of coal dust and the process of soil particle emission. The TSP major come from dust, fly ash and mineral particles such as gypsum, and the number of TSP of fine grain number is more than the number of coarse and more irregular shape having two or more mineral composition.