RESUMO
In México, uncontrolled landfills or open-dumps are regularly used as "sanitary landfills". Interactions between landfills/open-dumps and shallow unconfined aquifers have been widely documented. Therefore, evidence showing the occurrence of aquifer contamination may encourage Mexican decision makers to enforce environmental regulations. Traditional methods such as chemical analysis of groundwater, hydrological descriptions, and geophysical studies including vertical electrical sounding (VES) and ground penetrating radar (GPR) were used for the identification and delineation of a contaminant plume in a shallow aquifer. The Guadalupe Victoria landfill located in Mexicali is used as a model study site. This landfill has a shallow aquifer of approximately 1m deep and constituted by silty sandy soil that may favor the transport of landfill leachate. Geophysical studies show a landfill leachate contaminant plume that extends for 20 and 40 m from the SE and NW edges of the landfill, respectively. However, the zone of the leachate's influence stretches for approximately 80 m on both sides of the landfill. Geochemical data corroborates the effects of landfill leachate on groundwater.