Effects of other metals on cadmium uptake by sugarcane

Abstract

Effect of other metals (Cu, Fe, Mn, Pb and Zn ) and soil properties (pH, organic matter (OM) and oxidation-reduction potential (ORP)) on bioavailable cadmium uptake to sugarcane grown in contaminated area nearby the zinc mine deposit, Mae Sot, Tak province, was investigated. Soil and sugarcane samples (root, bagasse and juice) were collected to characterize the bioavailable fraction by comparing weakly bound fraction with the total metal content using ICP-OES spectrometer. Acid digestion (US EPA, Method 3052) and the first-two steps of BCR sequential extraction proposed by the Standards, Measurements and Testing Programme (SM&M) had been applied for determination of total metals and available metals, respectively. Studied soil samples showed a wide range of physicochemical properties: pH (5.79 to 8.07); OM (0.52 to 4.16 g/kg soil); ORP (-291.1 to 347.9). Of the elements studies, cadmium has a highest mobility since it presents the highest content in the first fraction (BCR1) followed by Mn, Zn, Pb, Cu and Fe, respectively. The concentration of all metals was high in root rather than juice and bagasse of sugarcane. This may imply that metals were absorbed, accumulated, and retained by the roots rather than translocated through shoot. Principal Component Analysis (PCA) together with correlation analysis showed supporting results to each other, implying that some interactions and/or relations existed among these metals (Cd, Pb and Zn) in both available and total forms. In addition, total Cd accumulated in 10 months sugarcane samples were analyzed for whole parts (root, underground stem, bagasse, juice, top and leave) and the result agrees with the first part that available Cd and available Zn in soil exhibits the correlation coefficient (r) = 0.473* and 0.431* at significant level 0.05, respectively.