Many a times solution to geoenvironmental problems necessitates advanced characterization of soil. These characterization results serve as inputs for mathematical modelling, parameterization of certain soil related functions, verification or validation of some phenomenon, field investigation, physical modelling of soil behaviour, indirect estimation of properties etc. While the list of such advanced soil characterization is exhaustive due to the recent developments in electronics and instrumentation, only some of the important and common advanced characterizations for geoenvironmental problem are discussed in the following.

5.1 Soil contaminant analysis
            A wide variety of instruments are available for analyzing the concentration of organic and inorganic contaminants present in the soil. In most of these methods, the contaminant present in the soil need to be first brought into solution form by using suitable methods. The contaminated soil is washed using water or suitable extractants in single, multiple or sequential steps (ASTM D 3974; Reddy and Chintamreddy 2001; Dean 2003; Maturi et al. 2008). Another process for extracting soil contaminants into solution form is by acid digestion method (Method 3050B, EPA). The contaminant in solution form is then analyzed using the appropriate method for contaminant analysis such as atomic absorption spectrometer (AAS), inductively coupled plasma mass spectrometer (ICP MS), ion chromatograph, gas chromatograph, flame photometer, UV visible spectrophotometer. The choice of contaminant analysis methodology would depend upon the type of contaminant and whether single or multiple contaminants need to be analysed. The accuracy of all these methods would depend upon the precise calibration performed by the user. In the process of calibration, instrument parameter is correlated to the contaminant concentration using standard contaminant solution of known concentration. Further, for a solution of unknown concentration, instrument parameter is measured and the concentration determined using the calibration equation.