Migration and translocation of topically applied copper, lead, zinc, cadmium and nickel in soil profiles during accelerated leaching

The partitioning technique for soil trace metal analysis was thoroughly reviewed. Several alternative extractants for each soil metal fraction were selected and tested for their selectivity which was evaluated by a specially designed selectivity index. A six-step partitioning procedure including an independent sulfide fraction extraction was proposed and the sulfide fraction was extracted by a solution of 6.0 % peroxide in 4.0N nitric acid. The partitioning procedure was employed in soil column leaching experiments; so as to study the migration and the translocation of copper, cadmium, lead, zinc, and nickel in soils and the factors affecting these processes. The results showed that the trace metal vertical migration was limited to a upper layer of few centimeters and was related to the readily available fraction. The mobility order of the five metals studied was: Ni = Zn = Cd > Cu = Pb. The amount of the readily available metals decreased throughout the entire leaching period. Among all factors affecting the soil trace metal behavior, soil microorganism population density was an important one. The metals appeared to be more mobile in the sterilized soil columns than in the unsterilized columns. A qualitative model was proposed to describe the migration and the translocation processes