The investigation of the Dry Deposition of Mercury and Other Compounds to Natural Water Surfaces is a cooperative research project between the U.S. Environmental Protection Agency, the University of Michigan's Air Quality Laboratory, the Illnois Institute of Technology and Canegie-Mellon University. The principal objective of project is the investigation of the dry deposition of mercury and other semi-volatile organic compounds to the Great Lakes and other natural water bodies, comparing directly measured deposition of these compounds with model calculations. The estimation of the dry deposition of mercury and other SOCs is not trivial, given that the currently available techniques for directly measuring dry deposition cannot be used for mercury and other SOC's because of interferences with grease surfaces typically used for such measurements and due to contamination. Further, the use of current dry deposition models to investigate the deposition of these compounds is unsatisfactory, given the incomplete knowledge of how the dry deposition processes involving mercury and other SOCs differ from other compounds.
The intial thrust of this project has aimed to address the critical need for the development and standardization of measurement and analysis techniques for metals, atmospheric mercury and other SOCs for process studies. The development of these methods is critical to our ability to understand the phase distribution of atmospheric mercury and the impact that this phase distribution has on the depostion of this critical pollutant to terrestrial and aquatic ecosystems. These methods have undergone initial testing and refinement through the performance of several field campaigns in the Great Waters basin. A two-week field study is scheduled for early September 1996 to complete the testing of the developed methods.