Studies of spatial variabilities of airborne metals across four different land-use types

Abstract

The concentrations of seven metals (Fe, Pb, Mn, Ni, Cd, Cu, and Cr) associated with the total suspended particles (TSPs) were analyzed regularly from the four sampling sites of different land-use types within the boundary of Won Ju city, Korea during 1991 through 1995. The mean concentration data for the four sites selected to represent grassland, residential, commercial, and industrial areas fell in a relatively broad range of: 1440-2240 (Fe), 88-326 (Pb), 2-4 (Cd), 8-21 (Cr), 194-469 (Cu), 32-95 (Mn), and 15-26 (Ni) ng m(-3). The data, when compared across the different study sites, generally exhibited systematic trends in accordance with the site-selection scheme; most metals exhibited increase in their concentration levels across grassland through industrial site. Examinations of data also indicated the possibility that spatial factors play complicated roles on both long- and short-term distribution of metals. From all four sites studied, several metals (e.g., Fe, Pb, Mn, Ni, and Cd) consistently showed their seasonal trends characteristic of high winter/spring values. In addition, the analysis of long-term distribution trends indicated that the concentrations of many metals dropped steadily at four sites (e.g., Fe, Pb, and Mn). When these metal data were compared among different sites (land-use types), significant correlations were seen frequently for such metals as Fe, Pb, Cd, and Cr. Investigations of inter-metal relationships indicated that strong correlations were more abundant from such metal pairs as Fe-Pb, Pb-Mn, and Mn-Fe. In addition, the cases for such strong correlations were seen more abundantly from grassland (and residential) than industrial (and commercial) site. Factor analysis was also conducted to distinguish source processes affecting metal distributions in the study area. Results of this analysis suggest that the metal distributions of the individual sites may be affected most significantly by distinctive source processes of their own.