Geophysical aspects of abandoned landfill geomorphological and material properties macro-characterization

Landfills (dumps) are places where the end of the life cycle of products can be found - useful material is dumped away from the sight creating contaminant flows around. Another problem is huge unexplored potential of resources recycling - we have limited knowledge also on useful elements and materials that are buried. The solution to overcome the limitations that provide remote sensing and traditional geodesy, proximal sensing techniques could be used. “Near surface geophysics” with operation at or just below the soil surface, significantly may contribute to give answers that traditionally are solved only after excavation. Geophysical methods are various, those can be active (i.e. create its own signal) or passive (i.e. register an existing signal); invasive (by inserting devices into the soil) or non-destructive. Some of these methods are static (e.g. a sequence of inserted electrodes), others can be used in a mobile way (e.g. pulled by a quad-bike). In general, their depth of exploration can vary from a few decimetres to some tens of metres. Thus in range of wide geophysical methodology spectrum almost all methods might be of use for unknown dump exploration depending on circumstances. In this paper, the aim is to macro-characterize anthropogenic geomorphological forms for contouring of old buried dumps by use of magnetometry, and geoelectric research methods to provide knowledge on approximate content of the dump. Protonmagnetometer was used in Eastern Latvia to determine unseen on surface dumpsite, buried in forest; induced polarisation and electric resistivity research was done in Southern Sweden for the macro-content analysis of dump hills composed of glass industry residuals and construction waste mixture. Geophysical surveying was performed to support site investigation with respect to landfill-related environmental problems, to enhance the opportunity for contouring of location of material mass and initially evaluate its physical properties. Results have shown good potential of geophysical surveying to spatially characterize landfill masses (location and dimensions) and to identify the internal structure of a landfill site, which already provides valuable information to estimate the landfill mining (material recovery) potential of landfills.