Grant: Discovery Grants Program - Individual

Mercury (Hg) is a toxic contaminant that accumulates in ecosystems, affecting the health of organisms and ultimately human health. While there is a wealth of research examining Hg cycling in freshwater and open marine ecosystems, the processes controlling Hg accumulation in more complex near-shore chemical transition zones such as estuaries are not well known. Estuaries are key sites of both ecological and economic productivity around the world, with high biodiversity value and highly populated and industrialized catchments. River estuaries are the largest source of Hg to coastal areas, but their changing physical and chemical dynamics make them challenging systems for predicting pollutant fate. The long-term vision of my research program is to quantify the fundamental variables controlling two critical processes: (I) Hg removal and retention in estuaries; and (II) Hg bioaccumulation in estuaries. Specifically, I will address a key knowledge gap regarding the role of suspended particulate matter (SPM) in Hg fate in estuarine ecosystems, and their influence on Hg photoreactions and accumulation. My research group is uniquely equipped to quantify mercury speciation and interactions with SPM. There is a need for better predictions of Hg retention, Hg removal, and MeHg bioavailability to help identify Hg-sensitive areas in estuarine ecosystems, and to mitigate Hg exposure to food webs. This research will also provide a better understanding of the sensitivity of ecosystems to Hg inputs and will facilitate the identification and management of estuarine areas at risk of Hg contamination. My proposed research program will provide the necessary tools for predicting these Hg-sensitive areas, such that food-web impacts can be mitigated. Despite increased regulation, global emissions of Hg are increasing, and Hg will continue to affect organisms in sensitive ecosystems worldwide. My research program is essential to understanding the primary factors controlling mercury retention and bioaccumulation in estuarine ecosystems. This work has significance for Canada and internationally, as estuarine ecosystems are central to our global environment, economy, and culture. The results will aid the implementation of national Hg policy (i.e., the UNEP global Hg treaty) and the development of risk management strategies for industrially impacted estuaries, such as those associated with hydroelectric facilities. This work is critical to the health of Canadian ecosystems, with direct impacts to populations that rely on these ecosystems.