title: Electro-migration of nitrate in sandy soil.
abstract: Migration of nitrate to groundwater has become a serious threat in many agricultural areas. This paper presents the results of experimental laboratory tests studying the nitrate gradient developed in response to an electrical potential. Two systems were tested; the first had no flow (closed system) and the second had flow opposite to the direction of the electrical current. A solution of sodium nitrate in sandy soil was used in both systems. The tests showed that the electro-kinetic process effectively concentrated and retained nitrate close to the anode. The movement of NO(3)(-) through the soil column was significantly influenced by the development of a pH gradient. Statistical analysis was performed to determine best-fit equations relating the nitrate gradient to the electrical input and pH gradient. A simple one-dimensional finite difference model was used to predict the pH gradient developed during the electro-kinetic process. The experimental measurements closely agreed with the predicted spatial and temporal distribution of the nitrate gradient for both closed and open system configurations.
authors.affiliation: National Water Research Center, Cairo, Egypt.
authors.forename: N
authors.initials: N
authors.lastname: Eid
authors.forename: W
authors.initials: W
authors.lastname: Elshorbagy
authors.forename: D
authors.initials: D
authors.lastname: Larson
authors.forename: D
authors.initials: D
authors.lastname: Slack
mesh_terms: D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009566:Nitrates / Q000493:pharmacokinetics*; D012989:Soil Pollutants / Q000493:pharmacokinetics*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*
chemical_list: D009566:Nitrates; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical