Application of Resistivity-ip to Mapping of Groundwater Contamination and Buried Waste

Combined resistivity and IP investigation is a powerful tool for mapping contaminant leakage as well as delineating the extent of contaminated ground and buried waste. Resistivity investigation is well established for detection and mapping of contaminated ground and groundwater. Low resistive zones around contaminated industrial sites and landfills correlate with high ion contents in groundwater due to leachate migration. A common problem is that the extent and composition of the buried waste is unknown due to poor or lacking documentation. Resistivity investigation alone can often not delineate the waste due to large variations in resistivity as a result of variation in water content. Time-domain induced polarisation (IP) can be used to measure the chargeability of the ground together with resistivity in a time and cost efficient way. Since buried waste commonly produces strong IP effects the chargeability can be used for delineating the waste. In this paper two field examples illustrate the use of this combined concept.