From theory to the complex geospatial ground-truth of contaminated soils

Characterization and subsequent reclamation of contaminated sites require detailed knowledge of the geospatialdistribution of contamination. In Italy, a potentially contaminated site is an area where the concentration of one ormore contaminants in soils is above land-use legal limits (CSC according to Italian law 152/06). Four main phaseshave to be followed to assess contamination and then reclamation: 1) preliminary conceptual model, 2) characterizationplan, 3) site specific risk analysis (by Risk-net software) setting the contamination threshold concentration(CSR), 4) assessment of contamination and therefore reclamation action by comparison between CSC and CSR.The geospatial distribution of contaminants is considered in the characterization plan. It is mandatory to sample atleast three samples for each surveyed point (one sample in the 0 to 1 m depth, one sample in the capillary fringezone and one in between). There aren't clear indications on the sampling strategy and spatial density. Accordingto Italian law (D.M. 471/99), it is usual to identify 5 to 15 sampling points for areas of 1 to 5 hectares.In this work we attempt to answer the question: "After more than a decade from the introduction of law 152/06 andconsidering the progress of scientific knowledge, are these soil sampling criteria suitable for assessing the spatialand volumetric distribution of site contamination?".