Dr. McLagan was an outstanding graduate student of our DPES Ph.D. program. He is the recipient of the (highly prestigious) Governor General’s Gold Medal and the initiator and founder of the DESC colloquium. Dr. McLagan’s Ph.D. research, co-supervised by Professors Frank Wania and Carl Mitchel, focused on the development and rigorous testing of a highly novel, passive (non-electrical) sampler for mercury in the air. His research carried a relatively undeveloped idea into a fully functional product that is now being used across the world. Dr. McLagan has an impressive record of academic achievements with a much greater number of exceptional quality journal articles than is the norm for the discipline, a commercialization agreement with a private company for an invention developed in his thesis work, tangible impact on current global mercury pollution policy and numerous important contributions to graduate student life at the University of Toronto. Dr. McLagan was extremely productive throughout his graduate work, achieving a spot in a class of his own. In addition to over 45 conference presentations (25 as presenting author and several invited!), he has 20 peer-reviewed papers in top-tier journals. He was recently an NSERC Postdoctoral Fellow at the Technical University of Braunschweig (Braunschweig, Germany) and an Assistant Professor for graduate studies at the University of Toronto. Currently, Dr. McLagan is an Assistant Professor and works in the FEWA Lab – Fire, Earth, Water, and Air: Contaminant Biogeochemistry Lab at Queen’s University.

Title of talk: 

A toxic legacy: Utilising polluted sites for mercury biogeochemical cycling assays. 

Abstract: 

Until Minamata disease, which caused >2000 deaths in the 1950s and 1960s (Minamata, Japan), was directly linked to mercury (Hg) pollution, use and emissions of Hg from production (mining and energy) and industrial processing were unregulated. Facilities such as these are commonplace around the world and Hg pollution from these sites has a lasting impact on human and environmental health. In 2019, I published a study that showed approximately 80 – 150 kg·yr­‑1 is emitted into the atmosphere alone from a former Hg mine in central Italy. While assessments of environmental emissions of Hg from legacy polluted sites and the effects of these emissions on local populations and ecosystems are of critical importance, these sites also provide the opportunity to study intricate details of the Hg biogeochemical cycle without constraints of analytical detection limits that can affect studies in background regions. Hg stable isotopes are a powerful analytical tool that provides unparalleled degree of detail on Hg sources and processes that control the transport, exchange, and fate of Hg in the environment. However, they are once such analytical system that becomes increasingly challenging as Hg concentrations in target matrices decrease. I will use this seminar to describe how I have been able to apply a multi-analysis approach led by Hg stable isotopes to improve our understanding of Hg biogeochemical cycling across environmental compartments in and around Hg polluted sites. This work involves studies tracking Hg emissions from industrial sources and then tracking its transport, transformation, and fate in coupled soil-groundwater systems, streams, atmosphere, and trees as well as exchanges between these systems. Ultimately, this work has direct applicability to the Minamata Convention on Mercury that highlights the importance of understanding “the environmental cycle … of mercury and mercury compounds in a range of ecosystems”.