Uncertainties on the Extension of a Polluted Zone

Data collected during the sampling of polluted sites are mainly used - through an exploratory and variographic analysis, to characterize to characterize the concentration level and the spatial variability; - at fixed support, to estimate the concentrations in order to map the pollution. Kriging gives also the standard deviation of the estimation error, making it possible to delimit the zones in which the estimation is considered to lack in precision. If a proportional effect is present the map of error standard deviation has to be corrected to take into account the increase of spatial variability with the local concentration mean.