Grant: Research Tools and Instruments

Selenium (Se) and mercury (Hg) are among the most important trace elements that bioaccumulate and magnify in aquatic food chains, posing potential health risks to predatory waterfowl and fish, as well as human populations consuming those, all across Canada, especially in the vicinity of certain types of industrial operations. Rare earth elements (REEs) are of increasing technical importance in many semiconductor and electronics applications, and find their way increasingly into the environment via landfill leachate and mining activities, which necessitates (eco)toxicological studies to determine if REEs pose risks to aquatic organisms or humans. There is evidence that in all of these processes, Se, Hg and REEs are often associated with insoluble particles or colloids (= small particles that cannot be removed by filtration), but there are currently no adequate analytical methods to quantify concentrations of particulate or colloidal Hg, Se or REEs in waters. With the requested funding, we would create a sample preparation laboratory at Wilfrid Laurier University (WLU), in which water samples are pre-treated by microwave digestion to the point where accurate quantification of particulate or colloidal Hg, Se or REEs becomes possible. The digestion happens in closed vessels to prevent losses of volatile Hg or Se compounds, and uses highly purified (by sub-boiling point distillation) acids and sample handling in particle-free environments (laminar flow hoods) to prevent sample contamination, which is necessary given the low native Se and Hg concentrations. The requested sample preparation facility would complement the newly constructed atomic mass spectrometry (ICP-MS) facility at WLU, in which the digested samples will be measured for Hg, Se or REEs. The proposed sample preparation facility (in combination with the ICP-MS facility under construction) would serve two main goals. First, it would be a state-of-the-art facility, in which analytical methods and sample preparation protocols can be developed and tested. These methods and protocols would then be transferred to the broader scientific and laboratory communities, so that they can be used widely in future studies, and thereby help generate more accurate environmental information. Second, we will subsequently use the developed methods ourselves to conduct selected crucial studies on the environmental and industrial behavior and relevance of particles and colloids containing Hg, Se or REEs, and thereby obtain a better understanding of the roles that such colloids and particles play in the environmental chemistry and toxicology of these elements.