Reducing Cd in contaminated soil by low cost materials from waste-agri

Abstract

    The study was conducted with purpose of accumulation evaluation of Cd in vegetables and the immobilization ability of available Cd in contaminated soil by compost straw and biochar. Contaminated soil with total Cd content of 5.013 ppm, available Cd content of 0.048 ppm was mixed with biochar and compost straw by proportions including 1.25%, 2.5%, 5% (w:w). The control formular (CF) is Cd contaminated soil without treatment materials. Experimental results show that vegetables can absorb up to 47.91% of available Cd. The accumulation of Cd in vegetables is in the order: roots > old leaves > young leaves. In addition, Cd content in leaf stems is lower from 1.44 - 1.51 times than roots, and Cd content old leaves is higher from 1.19 - 1.23 times than young leaves. The results of available Cd treatment by composted straw decrease from 1.63 - 3.99 times compared to the CF. Biochar with available Cd treatment efficiency is higher from 1.3 - 2.55 times than the compost straw at the same rate, and available Cd content reduces from 2.12 - 10.19 times compared to the CF. In which, the ratio of biochar 5% can contribute to optimal control with reducing 97.49% of available Cd