Grant: Research Tools and Instruments - Category 1 (<$150,000)

Human inputs of Nitrogen (N) to aquatic systems far exceed natural sources mainly due to agricultural fertilizer application, wastewater discharge and waste generated by livestock. The result of these human activities is elevated levels of ammonium (NH4+), nitrate (NO3-) and nitrous oxide (N2O) in both surface water and groundwater. Anthropogenic addition of excess bio-available N ultimately threatens aquatic ecosystem health and the security and quality of drinking water supplies. Population and water use in the Grand River watershed is expected to grow by 60% by 2031. Currently, more than $500 million in changes are being made to the two largest urban WWTPs (Kitchener & Waterloo) to allow dewatering of sludge and to increase in-plant nitrification where NH4+ is converted to to NO3- before discharge. Although the toxicity of NH4+ to aquatic organisms will be reduced, increases in NO3- in the river are expected to exceed the drinking water limit, particularly in winter. This is a critical problem for the many communities in the lower Grand River basin who use the river as their sole source of drinking water. Separating the role of agricultural and WWTP input of NO3- is instrumental to ensuring ecosystem health and providing for science-based management decisions. Isotopic analysis of NO3-, NH4+ and N2O can be used to distinguish different anthropogenic sources as well as their transformation N moves through the aquatic system.A laser N2O isotope analyser will permit the analysis of stable isotopes (15N/14N and 18O/16O) of N2O-, NO3-, NO2- and NH4+. The equipment will be immediately and heavily used by graduate and undergraduate students in scientific research on nutrient cycling. Data will be used in process based predictive modelling that will provide water managers with improved tools for ensuring drinking water quality and to promote overall aquatic ecosystem health.