Total Gaseous Mercury Measurements in Florida: The Fams Project (1992–1994)

Abstract

Measurements of Total Gaseous Mercury (TGM) in the atmosphere are being conducted as part of the Florida Atmospheric Mercury Study (FAMS). FAMS is a multi-year study focusing on the atmospheric transport and deposition of Hg and other trace metals at several locations in central and south Florida. A major component of this study, which this paper addresses, involves determining regional TGM concentrations and seasonal variability patterns at the various collection sites. Occasional problems were encountered in the collection efficiency of TGM on Au. The reason for this interference was not identified, but it was dramatically reduced by heating the collection columns to 80 °C. Atmospheric Hg samples are currently being collected using Au-coated silica sand traps from atop 48 ft. aluminum sampling towers using an unattended and automated sampling and data recording system. We currently have approximately a two year record of TGM, beginning in the summer of 1992, for the Lake Barco Site, located in central Florida approximately 30 miles east of Gainesville, FL. The records at the south Florida sites are shorter, ranging from one month at Andytown to 16 months at both Fort Myers and Fakahatchee Strand. Average TGM concentrations (ng/m³) for 3 to 6 day integrated samples at the various sites are: Lake Barco, 1.59 ± 0.58 (n=78); Fort Myers, 1.59 ± 0.40 (n=42), Fakahatchee Strand, 1.42 ± 0.41 (n=30); Tamiami Trail 1.46 ± 0.80 (n=27); Everglades National Park 3.11 ± 1.52 (n=13); and Andy Town, 1.78 ± 0.62 (n=3). The mean Hg concentration for all the sites is 1.64 ± 0.76 ng/m³ (n = 191).