PARENT SESSION

MA7 Global Atmospheric Transport
201 Oregon Ballroom
8:00 AM - 12:00 PM, Monday

() The BETR-World model: fate and transport of three mercury species in the global environment.

Toose, L¹, Mackay, D¹, ¹ Trent University, Peterborough, ON, Canada

ABSTRACT- The BETR-World mass balance model uses a set of 25 geographically explicit, linked regions to describe the global fate of both single- and multi-species chemicals. This model has been successfully applied to describe the global fate and transport of a single-species chemical, -HCH. Addressed here is an application to mercury. Mercury is a contaminant of particular concern because of its persistence, potential for long-range atmospheric transport and toxicity. Each of these fate and effect processes involve different, inter-converting, mercury species. The task of addressing several inter-converting species at once may be accomplished by assuming fast conversion rates between species, therefore constant species proportions in each compartment. The traditional single-species fugacity modeling approach utilized by the BETR-World model has been modified by a novel method which uses "multipliers" derived from the constant species proportions. The fate and transport of elemental, divalent and methylated species of mercury can then be described simultaneously. This method allows insight to be gained regarding the long-range transport pathways of mercury and other potentially toxic compounds, their precursors and degradation products to relatively pristine environments. The model can be used to assess the relative efficiency of transport of mercury from various source regions to specified receptor regions, such as the Arctic. In addition, the potential exists to describe a global mercury mass balance.

Key words: mercury, long-range transport, global model, arctic