Metals Mobility and Uptake of Chinese Mustard at Different Levels of Soil Contamination

Abstract

Mobility of metal as Cd, Zn, Cu, Pb and Cr were studied to determine effect of spiked concentration on metals fractions using sequential extraction procudure to identify metal in five forms, i.e., water soluble, exchangeable fraction, carbonate bound, oxide bound, organic bound and crystal lattice or interlayer and their relationship to metal uptake of Chinese mustard. Experiment had performed with sandy loam texture, high OM and slightly acid soil. Pot soils were spiked with single element metals at 3 concentrations; 1) no spiked 2) low level with regard to allowable level and 3) high level with regard to the severe contaminated land. The result showed that the response of metals on spiked concentration related to their affinity to soil components such as cadmium and zinc in oxide fraction, copper in organic fraction, lead and chromium in crystal lattice and organic fraction. Effect of spiked concentration of cadmium, zinc and copper clearly explicited on exchangeable and carbonate fraction but not significant in lead and chromium. Concentration releationship of cadmium and zince exhibited L-curve, while, copper exhibited S-curve. The releationships between the exchangeable fraction in soil and concentration in plant was significant correlated in cadmium, zinc and copper case, but carbonate fraction was significant correlated in cadmium and zinc case. The study provide the evident supported the applicable of exchangeable fraction on mobility and bioavailability of five metals in soil and conclude that metal fraction provide a better indicator for metal mobility and bioavailability than total metal content.