Abstract
Removal techniques of heavy metals in contaminated soil are sometimes unfeasible because of high cost and/or low efficiency on a large scale, and thus the immobilization process of metals in soils using soil amendments has been gaining prominence as an alternative solution, which aims at suppressing uptake of toxic metals to crops. We focused on the potential of organic matter as an aid in heavy metal-immobilization, and assessed the availability of cow manure and methane fermentation digestive liquid (hereafter, CM and LM respectively) for establishment of safe farming by carrying out batch tests covering Cu, Cd and Pb. The results from the experiments showed that CM had high immobilization effect, especially for Cu, available forms decreased by approximately 90%. However, it was found that the immobilization effect on Cd was less than that on the others and that the mobility of Cd was enhanced under coexistence of other metals, which suggested that the immobilization manner in a dune sand was significantly different among metals as well as environmental conditions. Besides, although the availability of LM was lower than CM, the analysis of speciation indicated that LM also had the potential to reduce phytoavailability of metals.
