论文部分内容阅读
After the phase-out of leaded gasoline,coal burning is considered as the major source of lead(Pb)in the atmosphere and power plants are one of the major consumers of coal.Hence,to quantify the emission of Pb in the atmosphere and to estimate the present atmospheric Pb isotopic signature,elemental concentration of lead(Pb)and its isotopes were measured in coal,fly ash,bottom ash,limestone and gypsum from different power plants in Guizhou Province,China.The Pb concentration varied between 1 ?g/g and 83 ?g/g.The lowest concentration was measured in the limestone and gypsum and the highest concentration were observed in the fly ash from all of these power plants,with bottom ash showing Pb concentration between 20-30 ?g/g.The 206Pb/207Pb isotope ratios in showed wide ranges from 1.18 – 1.26 for coal,1.19 – 1.43 for bottom ash,1.19 – 1.42 for fly ash and 1.21 – 1.35 for limestone and gypsum.For isotopic ratios,208Pb/204Pb,207Pb/204Pb and 206Pb/204Pb,narrow ranges were observed with average value of 39.20±0.18,15.74±0.09 and 19.87±1.28,respectively.Unlike the isotopic signature of leaded gasoline which was fairly consistent with global isotopic signatures,the wide ranges of 206Pb/207Pb(1.18 – 1.42)may suggest that the isotopic composition of the atmospheric aerosols at present could be in-homogenous in terms of local,regional and global signature depending on the source areas,wind movement and atmospheric mixing process.