Source Attribution for Mercury Deposition to the Great Lakes Region in the Context of Global Change

Abstract:

Mercury contamination in the Great Lakes region has important implications for human and wildlife health therein. Atmospheric deposition serves as an important pathway for mercury entering into the lakes and mercury originating from sources outside North America also contributes to part of the total mercury deposited to the Great Lakes. Understanding the source apportionment of mercury deposition to the Great Lakes region is critical for policy making. We investigate the present day source attribution of mercury deposition to the Great Lakes region as well as the perturbations driven by various factors in the context of global change (such as the changes in biomass burning emissions, anthropogenic emissions and land use/land cover) using the GEOS-Chem global model. We will quantify the relative contribution of different emission sources (e.g., anthropogenic vs natural) and different regions (e.g., domestic vs intercontinental-transport) to mercury deposition in the Great Lakes region. In addition, we will conduct sensitivity tests to evaluate the model’s sensitivity to processes such as atmospheric redox reactions and how it affects the source attribution.