John Spoelstra

Research Scientist - Groundwater Quality
Environment and Climate Change Canada

Current research and/or projects

Contributing to Environment Canada’s mandate to ensure aquatic ecosystems are conserved and protected

  • Sources and fate of nutrients in groundwater and surface water
  • Use of artificial sweeteners to detect wastewater in the environment
  • Impacts of land management on water quality
  • Development and application of stable isotope tools for biogeochemistry research
  • Groundwater quality issues of the Great Lakes Basin

Education and awards

Ph.D. Earth Sciences, University of Waterloo, 2004

Hon. B.Sc. University of Waterloo, 1996

Key publications

Spoelstra, J., N.D. Senger, S.L. Schiff. (In press) Artificial sweeteners reveal septic system effluent in rural groundwater.  Journal of Environmental Quality. doi: 10.2134/jeq2017.06.0233.

Roy, J.W., J. Spoelstra, W.D. Robertson, W. Klemt, S.L. Schiff. (In press) Contribution of phosphorus to Georgian Bay from groundwater of a coastal beach town with decommissioned septic systems. Journal of Great Lakes Research. doi: 10.1016/j.jglr.2017.09.001.

Snider, D.M., J.W. Roy, W.D. Robertson, D.I. Garda, J. Spoelstra. (2017) Concentrations of artificial sweeteners and their ratios with nutrients in septic system wastewater. Groundwater Monitoring & Remediation 37(3): 94-102. doi:10.1111/gwmr.12229.

Snider, D.M., C. Wagner-Riddle, J. Spoelstra. (2017) Stable isotopes reveal rapid cycling of soil nitrogen after manure application.  Journal of Environmental Quality 46: 261-271. doi:10.2134/jeq2016.07.0253.

Van Stempvoort, D.R., J. Spoelstra, N.D. Senger, S.J. Brown, R. Post, J. Struger. (2016) Glyphosate residues in rural groundwater, Nottawasaga River Watershed, Ontario, Canada. Pest Management Science 72: 1862-1872. doi:10.1002/ps.4218.

Robertson, W.D., D.R. Van Stempvoort, J. Spoelstra, S.J. Brown, and S.L. Schiff. (2016) Degradation of sucralose in groundwater and implications for age dating contaminated groundwater. Water Research 88: 653-660. doi:10.1016/j.watres.2015.10.051.

Robertson, W.D., D.R. Van Stempvoort, J.W. Roy, S.J. Brown, J. Spoelstra, S.L. Schiff, D.R. Rudolph, S. Danielescu, and G. Graham. (2016) Use of an artificial sweetener to identify sources of groundwater nitrate contamination. Groundwater, 54: 579-587. doi:10.1111/gwat.12399.

Snider, D.M., K.A. Thompson, C. Wagner-Riddle, J. Spoelstra, and K.E. Dunfield. (2015) Molecular techniques and stable isotope ratios at natural abundance give complementary inferences about N2O production pathways in an agricultural soil following a rainfall event. Soil Biology & Biochemistry 88: 197-213. doi:10.1016/j.soilbio.2015.05.021.

Snider, D.M., J.J. Venkiteswaran, S.L. Schiff, and J. Spoelstra. (2015) From the ground up: nitrous oxide sources are constrained by stable isotope values. PLoS ONE 10(3): e0118954. doi:10.1371/journal.pone.0118954.

Li, L., J. Spoelstra, W.D. Robertson, S.L. Schiff, and R.J. Elgood. (2014) Nitrous oxide as an indicator of nitrogen transformation in a septic system plume. Journal of Hydrology 519: 1882–1894.

Spoelstra, J., S.L. Schiff, and S.J. Brown. (2013) Artificial sweeteners in a large Canadian river reflect human consumption in the watershed. PLoS ONE 8(12): e82706. doi:10.1371/journal.pone.0082706.

Spoelstra, J., S.L. Schiff, R.G. Semkin, D.S. Jeffries and R.J. Elgood. 2010. Nitrate attenuation in a small temperate wetland following forest harvest. Forest Ecology and Management 259: 2333-2341.

Spoelstra, J., S.L. Schiff, P.W. Hazlett, D.S. Jeffries and R.G. Semkin. 2007. The isotopic composition of nitrate produced from nitrification in a hardwood forest floor. Geochimica et Cosmochimica Acta. 71: 3757-3771.

Schiff, S.L., J. Spoelstra, R.G. Semkin and D.S. Jeffries. 2005. Drought induced pulses of SO42- from a Canadian Shield wetland: Use of δ34S and δ18O in SO42- to determine sources of S. Applied Geochemistry. 20: 691-700.

Spoelstra, J., S.L. Schiff, R. Elgood, R.G. Semkin, and D.S. Jeffries. 2001. Tracing the sources of exported nitrate in the Turkey Lakes Watershed using 15N/14N and 18O/16O isotopic ratios. Ecosystems. 4:536-544.