Application of rotating coiled columns to the fractionation of soil particles and to the sequential extraction of heavy-metal species from silty, dusty, and sandy fractions

A complex procedure has been developed for evaluating the degree of soil contamination. Rotating coiled columns (RCCs) were used for both the fractionation of soil samples by their grain-size composition and the sequential extraction of heavy-metal species from silty, dusty, and sandy fractions. During the extraction of heavy-metal species, the soil fraction to be analyzed was retained in the column as a stationary phase, while aqueous solutions of extracting agents (mineral salts, acids, and complexine, compounds) were sequentially pumped through the heterogeneous sample. The sequential extraction of element species from various soil fractions was carried out in the dynamic mode favorable to more complete extraction of metals. The use of RCCs allows the extraction of various heavy-metal species from soils to be performed in accordance with their grain-size composition. The process of the extraction of metal species can be automated, and in this case the losses of sample components are reduced to a minimum.