**6. Conclusions**

 We presented geophysical case studies conducted at MSW disposal sites in Brazil, to show the usefulness of resistivity and IP methods in characterizing these contaminated sites. The examples showed here show different types of waste disposal practice worldwide: direct disposal of wastes on the ground in geologically unfavorable and favorable conditions and proper landfills. We demonstrated that electrical methods are a powerful tool in identifying the presence of wastes in the subsurface and the boundary of the waste volume. Contamination plumes can also be detected with electrical methods, even for low contaminant concentration. Chemical analyses of groundwater are always needed to confirm contamination according to the environmental regulation. When the geophysical signature waste disposal sites are well defined and confirmed, geophysical methods can be used to monitor the temporal evolution of the contamination at the site.
