Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). The soil contamination intensity of a compound is governed by the concentration in the SOM (Com), i.e., the effective contamination level, rather than by the concentration in whole soil (Cs). This SOM-based index is considered timely needed for a evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites.

Soil organic/mineral matter;partition;adsorption;effective contamination level