Landfill Soil Characterization by Hyperspectral Imaging

The development of innovative, low cost and reliable landfill soil characterization and monitoring strategies represent the main target when control actions have to be applied to follow the interaction of waste dumps with the environment. Soil analysis is usually performed in two steps: i) “in-situ” sampling and ii) laboratory analysis. This approach is expensive and does not allow to reach, for the intrinsic limits (high costs) linked to direct sampling and polluting elements detection, an immediate and detailed knowledge of an area, especially when large regions have to be investigated. Numerical strategies are thus applied to perform the modeling of the collected data. These models are usually difficult to handle both for the intrinsic variability characterizing the media (soils) and for the high level of interactions between polluting agents, soil characteristics (organic matter content, size class distribution of the inorganic fraction, composition, etc.) and environmental conditions (temperature, humidity, presence of vegetation, human activities, etc.). Starting from previous researches, addressed to evaluate the potentialities of hyperspectral imaging approach in agricultural soil characterization, this study was addressed to evaluate the possibility to utilize this technique to perform a monitoring of bentonite clay strata level of contamination, due to the presence of leakage fluids, when such a material is utilized as bottom liner in landfill. The study shows as a correlation can be established between clay spectral response and its level of contamination.