New evidences of leachate plumes detected by a geoelectric studies at a

POMPOSIELLO,C DAPEÑA C. FAVETTO A

Perugia, ITALIA

Congreso; IUGG XXIV General Assembly IAGA; 2007

IUGG

Sanitary landfilling 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 these methods. This works reports new data obtained from two landfills of different age located in Gualeguaych city, Entre Ros province, Argentina. Several geoelectric studies, horizontal profiling and vertical sounding using dipole-dipole and Shlumberger electrode configurations were done. Important conductivity anomalies have been detected below the waste disposal. The 2D model obtained within the landfill shows a first layer with a thickness of (2 - 3) m and a resistivity range from 100 to 1000 ohm-m. The second layer has a thickness of (4 5) m and a low value of resistivity (3 to 6 ohm-m), which is attributed to the contaminated zone. The third layer has a thickness of more than 10 m and a resistivity of 15 ohm-m. Below this depth is observed another conductive layer (5 ohm-m). The 2D model obtained outside the landfill boundary presents a conductive layer at the same level of the inside one and its shows that contamination exists at the border of the waste disposal. These results agree with the value of the specific conductivity determined in the monitor phreatimeters.