Assessment of the mass of pollutant in a soil contaminated with chlorinated solvents.

Abstract: The scarcity of housing has led more and more developers to turn to the conversion of former industrial areas into residential areas. Brownfield redevelopment involves the cleanup of contaminated soil to eliminate any health or environmental risk. The quantification of the amount of pollutant in soil is essential to carry out an efficient remediation. It involves sampling and analyzing the soil to determine the concentration of pollutant at a finite number of locations. It is therefore necessary to assess the pollutant amount at unknown locations to estimate the pollution for the whole site. The existing methods used by the depollution actors often lead to underestimation or overestimation of the contamination possibly creating environmental, economic and legal issues. This study aims to compare different methods to assess the mass of pollutant using data from a site contaminated with chlorinated solvents. The methods comprise currently used methods (Mean 1, Mean 2), simple interpolation methods (Thiessen Polygons, Natural Neighbor, Inverse Distance Weighting) and a method based on a complete geostatistical approach (Conditional Simulations). They are compared to determine the variability of the results obtained with a specific set of data depending on the chosen method. The deterministic methods, although easy to apply, will often underestimate the mass of pollutants contained in soil whereas the geostatistical approach can give a more realistic result, but is complex to implement.