Innovative multifaceted approaches for tracing the sources and fate of nutrients and contaminants in watersheds

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Nitrogen (N) and phosphorus (P) containing compounds have the potential to induce major water quality degradations affecting drinking water quality and may cause eutrophication of continental water bodies. N and P in agricultural fertilizers, in urban runoff and wastewater effluents, and from industrial point sources cause increasing nutrient releases into surface water and groundwater bodies. Tracing the sources, the transport and the fate of N and P compounds in watersheds remains a major challenge. The objective of this 5-year research program is to develop an innovative tracer approach that combines novel isotope fingerprinting tools with more established chemical and isotopic approaches, water age-dating methods, and leading-edge microbiological and metagenomic techniques. Based on a thorough inventory of isotopic fingerprints of P and N sources relevant in the investigated watersheds, the scientific approach used in this research program will be comprised of a combination of aqueous geochemistry and novel and established isotopic tracer techniques to determine the predominant sources affecting nutrient loading of surface water and groundwater systems. In addition, my research team will advance our capabilities to unravel the biogeochemical reactions that affect the occurrence and persistence of these nutrients in the investigated aquatic systems. This will be achieved by conducting laboratory experiments and bioreactor microcosm studies, controlled nutrient tracing in artificial streams and an experimental wastewater treatment plant, and watershed-wide studies accessing surface water and groundwater bodies in Western Canada. Leading-edge techniques such as metagenomics, RNA and protein sequencing, as well as other microbiological approaches will be used to obtain complementary evidence for identifying the predominant processes and the key microorganisms involved in controlling the fate of nutrients and the persistence of contaminants in the investigated aquatic systems. Furthermore, water age-dating techniques will be employed to gain insights about water transit times in the investigated aquatic systems. The innovative combination of these approaches is expected to yield a much improved understanding of sources and timelines involved in nutrient and contaminant loading of aquatic systems, and will result in novel insights into the predominant processes and approximate reaction rates leading to biodegradation of nutrients and contaminants in surface water and groundwater systems. The obtained knowledge will be essential for developing future water management strategies for safeguarding or remediating of aquatic systems in Canada and elsewhere.