An Investigation of Possible Long-Range Transport of Mercury to South Florida Using the SLAM and ORCHID Models

摘要

The objective of this study is to study the possibility of long-range transport of mercury to South Florida. Results of a three-year climatological study using the Short-range Layered Atmospheric Model (SLAM) transport model from Cumberland City, Tennessee are presented and the potential for longrange transport to Florida is discussed. Resutls indicate favorable transport from Cumberland City to Florida during the winter (Dec-Feb) and spring (Mar-May) seasons. The transport, transformation, and fate of mercury in the atmosphere has been modeled during periods of favorable transport to south Florida using the Organic Chemistry Integrated Dispersion (ORCHID) model, which contains the transport model used in the climatology study. SLAM/ORCHID results indicate that it is unlikely for Hg~0 to reach south Florida from the source. However, results do indicate that oxidation products such as HgS and Hg(OH)_2 can be formed and transported to south Florida. ORCHID results indicate that the quantity and distribution of oxidation products which are formed and transported depend on (1) the composition of the source (e.g., Hg only or Hg released as part of a NO_x/SO_x source), (2) dry deposition modeling and land use (e.g., no deposition, mixed forest, rangeland) and (3) ambient concentrations (suburban versus rural).