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Modeling of Electromagnetic Soundings to Detect Groundwater Contamination by Intensive Livestock Farming
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics, Sep 2015, Volume 2015, p.1 - 5
Abstract
The feedlots, farms for feeding animals in corrals, are spreading at Buenos Aires Province, Argentina. It is important to evaluate the contamination by mineralization of organic matter. Geophysical exploratory methods give an important tool for monitoring groundwater and soil quality. The objective of this work was to perform electromagnetic soundings and to do a modeling of these data by an inversion procedure for different frequencies at a corral of a feedlot and the surroundings. The survey was repeated the following year. Bellow the corral, the unsaturated zone has lower resistivity (between 8 and 17 ohm m, more conductive) than the test zone. The second year, the test zone showed greater range of values for resistivity (up to 54 ohm m) but the layers bellow the corral showed an important decrease of resistivity. Groundwater samples were taken along four years. An increase of water conductivity was found at the lower well along the time.
The EMI modelling allowed characterizing the distribution of resistivity bellow the corral and the background, reaching the groundwater, detecting an increase of salinity bellow the corral which may be mainly due to leaching of nitrates.