Gao, Yuan2017-11-272017-11-272016-05https://hdl.handle.net/11299/191290University of Minnesota M.S. thesis. May 2016. Major: Environmental Health. Advisor: Matt Simcik. 1 computer file (PDF); vii, 47 pages + 1 supplementary table.Nitrate (NO3-) is a reactive nitrogen compound and can be utilized by living organisms. Industrial nitrogen fixation methods have greatly increased the production of reactive nitrogen and ultimately increased concentration of nitrate in natural waters. In natural streams, nitrate is recognized as a pollutant that can lead to some serious health issue for humans. Therefore, knowing the nitrate concentration in streams is critical to the environment and human health. Nitrate is not a major ion in natural waters. It would be very helpful if nitrate concentration could be estimated from other frequently measured parameters of stream, allowing ones to predict the nitrate concentration from other, more easily measure parameters. The largest data set of ionic composition of streams that has ever been compiled was used to examine the relationships among nitrate concentrations, major ion concentrations, and two bulk measurements of ionic content, ionic strength and specific conductance.enionic strengthnitratespecific conductancewater chemistryThesis or Dissertation