Many studies over the last two decades have employed the pyrrole polymerization processes, including several utilizing polypyrrole (PPY) doping with various ions and the application of these doped polypyrrole films as ion selective electrodes (ISE). This work extends these studies in two directions: 1) miniaturization of an ise for nitrate anions, based on nitrate-doped PPY films on a substrate of 7 um carbon fibers, and 2) application of these PPY(no3-) electrodes to nitrate transport experiments in an intermediate scale physical aquifer model, which is a prototype of environmental (in situ) measurements of nitrate in soils. Successful completion of this project will lead to the deployment of distributed nitrate sensor networks in complex environments, including soils, ground and surface waters.