The use of 2D electrical tomography to assess pollution in slurry ponds of the Murcia region, SE Spain

A large quantity of pig slurry is produced in the Murcia Province, raising serious environmental concern. Monitoring the evolution of the slurry ponds with time in the subsoil is a prime requirement for environmental safety. Our aim was to determine the temporary effects of pig slurry ponds on the subsoil in the Murcia Province to establish the degree of slurry pond infiltration in semi-arid climates. A non-destructive, geophysical, 2D electrical tomography technique was used to: 1) monitor the vertical movement of pig slurry into the subsoil and 2) determine the possible depth of this movement. The results of our studies showed that the method works well. Areas affected by pig slurries have, indeed, developed environmental problems over time. The method identified the lithological layers with sufficient resolution in order to study the possible pollution of the soils by the slurry, including salts. The method is also capable of monitoring seasonal changes and the timedependent behaviour of the polluting plume within different subsoils in the ponds. © 2009 European Association of Geoscientists & Engineers.