TRACE METAL TRANSPORT TO THE EVERGLADES: APPORTIONING GLOBAL, REGIONAL AND LOCAL SOURCE CONTRIBUTIONS IN AEROSOLS

Joseph R. Graney,* (Department of Geological Sciences, Binghamton University,

P.O. Box 6000, Binghamton, NY, 13902-6000, USA), J. Timothy Dvonch, Gerald J.

Keeler (The University of Michigan Air Quality Laboratory, Ann Arbor, MI, 48109

-2029, USA) Robert K. Stevens and Matthew S. Landis (U.S. Environmental

Protection Agency, Research Triangle Park, NC, 27711, USA)

Temporal and spatial variation in source-receptor relations for Hg and other trace metals in aerosols were investigated in south Florida in 1995 as a part of the South Florida Atmospheric Mercury Monitoring Study (SoFAMMS). PM10 and PM2.5 samples were collected over integrated 12-hour periods concurrently at 6 sites continuously from August 6th to September 6th. Major and trace metals in the aerosols including Si, Al, Fe, K, Mn, S, Zn, Pb, Cu were measured using XRF techniques while Hg was measured using CVAFS. Elevated concentrations of crustal elements (Si, Al, Fe, Mn and K) were measured at all receptor sites following the passage of tropical storms through or near south Florida. Global scale transport of Saharan dust is the likely source of the elevated levels of crustal elements in the aerosols. Elevated concentrations of sulfur were measured at all receptor sites associated with regional flow from the northwest to the southeast, suggesting episodic transport of sulfate aerosols from the United States to south Florida. The concentrations of Hg, Zn, Cu and Pb in aerosols were much more variable on temporal and spatial scales than the crustal element and sulfur concentrations. Local point sources of trace metal emissions including municipal and medical waste incinerators as well as cement kilns were sampled during SoFAMMS and found to be major sources of anthropogenic metals including Hg, Zn, Cu and Pb to the atmosphere in south Florida. Based on transport modeling, source sampling and statistical analysis, the source of most of the Hg, Zn, Cu, and Pb in aerosols transported to the Everglades during SoFAMMS originated from local anthropogenic point sources in south Florida.