Effect of applying municipal solid waste on accumulation of heavy metals in soil and rice plant in two years  Oryza sativa L.'

In order to study the effect of municipal solid waste application with or without chemical fertilizer on the concentration of heavy metals in soil and rice plant, an experiment was conducted with randomized complete block design in three replications and fourteen treatments in Research Station of Sari Agricultural and Natural Resources University in 2009 and 2010. The treatments included control treatment, chemical fertilizer, 15, 30 and 45 ton/ha municipal solid waste compost and chemical fertilizer at three levels (25, 50 and 75 percent). Results indicated that applying compost for two years showed no significant effect on any of the available heavy metals in soil. However, significant increases were observed for Lead (Pb2) in root, and Pb2, Cd2, Nicle and Cobalt in shoot and Cadmium (Cd2) in grain. Meanwhile, the highest amount of heavy metals was concentrated in 45 t/ha of municipal solid waste 75 percent chemical fertilizer treatment. Thus, using municipal solid waste compost, the amount of the heavy metals increased in soil and rice plant but their concentrations were below their toxicity limit.