CONICET | Buscador de Institutos y Recursos Humanos

Sanitary landfill is the most common way to eliminate solid urban wastes. An important problem associated to this practice is the leachate production and the related groundwater contamination. The leachate electrical conductivity is often so much higher than natural groundwater, consequently a large contrast in this property is seen which enables the plume to be detected using geoelectrical methods. This works reports new data obtained from two landfills of different age located in Gualeguaychú city, Entre Ríos province, Argentina. Several electrical resistivity tomographies show important conductivity anomalies below the waste disposal. The hydrochemical parameters computed in the most conductivity zone were useful to evaluate the present environmental conditions. Outside the landfill boundary the model presents a conductive layer at the same level of the inside one and it shows that contamination exists at the border of the waste disposal and also the presence of clay. In seven monitor phreatimeters the specific conductivity has been determined. There is a good linear correlation between the electrical conductivity of the aquifer determined from the geoelectrical model and the conductivity of the groundwater measured in the monitor phreatimeters. This indicates that the formation factor is nearly homogeneos in the aquifer. The porosity has been determined around 54% and the resistivity of the clay was estimated in 20 ohm m. Also, the total porosity with a gravimetric method in laboratory was determined on extracted material of the cover and a value of 61% was obtained.