A Study on Reduction and Transport of Cr(VI) in Two-dimensional Soils with Root Systems

This paper presents reduction effect and evaluation of Cr(VI)-contaminated soil by two kinds of plants on various initial concentration on laboratory testing. In this experiment, we prepared semi-two-dimensional experimental apparatus which could evaluate movement of water and pollutant and growth of plants two-dimensionally. Simulated polluted soil mixed with K 2 Cr 2 O 7 powder as pollutant homogeneously and compacted. Selected plants were komatsuna ( Brassica rapa var. perviridis ) and sunflower ( Helianthus annuus ). Effect of reduction was confirmed by checking water content, pH, standard oxidation-reduction potential Eh, water soluble Cr(VI) of soil separated in 10 cm depth and 5-7.5 cm width respectively with changing time. Cr(VI) in plant body was also investigated at the end of test. 1) The higher initial concentration of Cr(VI), the lower root length density which describes root length in unit weight of soil for both of plant. 2) For komatsuna, reduction rate of Cr(VI) in the soil was ranged between 16-48 %. For sunflower, reduction rate of Cr(VI) in the soil is ranged between 27-45 %. It differed from initial concentration of Cr(VI).