The Impact of Boreal Forest Disturbance on Watershed Mercury Dynamics. Rob Mackereth, Research Scientist with the Center for Northern Forest Ecosystem Research, OMNRF

Mercury is a natural element occurring in air, water and soil, but environmental levels have increased over the past century primarily due to industrial pollution at a global scale. The organic form of mercury, methylmercury (MeHg), can bioaccumulate and biomagnify in aquatic food webs posing a risk to aquatic organisms and other animals that feed on them. In Ontario, most fish consumption advisories are due to mercury contamination. Disturbances such as forest management or forest fire have been shown to influence mercury in forests and in some cases increase the levels in aquatic systems. This presentation will discuss the complex processes involved in forest mercury dynamics, review some research on the issue for northwestern Ontario and beyond and discuss efforts by MNRF to develop best management practices during forest management operations which may help to reduce the mobilization of mercury, and other metals and nutrients, stored in forest soils.