Sampling Model for Contaminated Bulk Soil Masses

The determination of the contaminant concentration in excavated and stockpiled bulk soil masses is of great importance in soil remediation practice. Both risk analysis and remediation planning are based upon a concentration determination which should be as exact as possible. The sampling of bulk soil masses must be distinguished from the sampling of standing soils and is easier, because the soil is more or less completely mixed due to excavation and heaping. Neese and Breiter [1] have recently reviewed the current understanding and practical experience with the sampling of contaminated soil. Up to now no national or international standards governing sampling from contaminated bulk masses exist which are based upon scientific principles. For that reason much research must be done. Practical experience shows that sampling errors frequently reach several hundred percent. Therefore an obvious contradiction exists between sampling precision and the precision of the subsequent instrumental analysis. A scientifically founded sampling is based upon a sampling model which provides information about the sampling error as a function of both the number of samples taken and the sample masses. Similar models for mineral raw materials have been developed in the past [2, 3], but they do not account for the specific conditions present in contaminated soils. In this paper principles of sampling based upon a simplified model are presented.