A Comparative Study On The Distribution Of Heavy Metals And Their Deposition Fluxes In Qingdao Area

Total Suspended Particle (TSP) and Particulate Matter with aerodynamic diameter less than 10μm (PM₁0) aerosol samples were collected at Mont Baguan and High-Tech Park in Qingdao coastal region from March 2001 to May 2002, especially during spring dust-storm period. Deposited particles were also directly collected with surrogate surfaces for the estimation of total deposition fluxes. The concentrations of six metals including Al, Fe, Mn, Cu, Pb and Zn were determined by means of ICP-AES. The temporal and spatial variations were discussed. Sources of metals were identified by calculating the enrichment factors relative to Al (EF_Al) and by correlation analysis. The deposition fluxes and velocities were estimated.The results showed that the concentrations of crustal elements (Al and Fe) in eastern area (High-Tech Park) were higher than in western area (Mont Baguan), while the concentrations of anthropogenic elements (Pb, Cd and Cu) showed a reversed pattern. The average drydeposition fluxes were determined to be 15.4mg.m^-2.m^-2.a^-1, 2.4 mg.m^-2.a^-1 , 3.6 mg.m^-2.a-1, 832 mg.m^-2.a^-1 and 2021 mg.m^-2.a^-1 for Pb, Cd, Cu, Fe and Al, respectively. These values are obviously higher than the corresponding wet deposition fluxes, especially for crustal elements. The result suggests that, in Qingdao coastal area, dry deposition of aerosols is an important pathway for the input of trace metals as well, if not more, especially during the dust-storm period.Enrichment factors (EFs) and other statistics methods were used to discuss the different sources of these metals in aerosol. The result shows that the EF_Al of Fe, Mn in PM₁0 are approximately 1, indicating these two elements were mainly supplied by wind-dust with very limited contribution from local anthropogenic source, the EF_Al of Zn, Pb, Cd and Cu are much higher than 1, these elevated EF_Al values suggest their anthropogenic nature of these heavy metals. However, it seems that the origin of Cu is not the same with Pb and Cd as indicated bythe correlation analysis, while Zn is most influenced by local specific pollution sources.The concentrations of PMio ranged froml3.80 to 306.46 //g-irf3 in 12 samples. Compared with TSP, the elements Cu, Pb, Zn are more easily distributed on PMio fraction. The correlation analysis of PMjo indicated that Al, Fe and Mn are mainly originated from crust and wind-dust, and the concentrations of Cu, Pb and Zn in PMio are predominated by anthropogenic sources, with Pb and Zn having similar anthropogenic origin.Based on the concentration measurement and the deposition velocities suggested by GESAMP, the deposition fluxes of the six metals were estimated. They are compared with the model-estimated dry deposition velocities and the direct measurement (total minus wet deposition).A new catalyzed photometric method was developed for the determination of iron, and the condition of determination has been discussed. It is demonstrated that the method is simple and convenient, yet feasible.