In this study, laboratory-scale column tests were conducted to investigate the leachingbehaviour of alkaline paddy soils polluted by a heavy-metals. Limestone was applied asa stabilization agent. The limestone was applied under the normal and acidic conditions(pH=5.6, 4.6, and 3.6), representing an acidic rainfall situation. From the test results, it wasobserved that the heavy metals could be released at the early stage of the supply of acidicsolution even in highly alkaline soil. Especially Cd and Zn have shown abrupt or continuousleaching with the supply of acid solutions. Because normal rain is slightly acid with a pH =5.6, it was anticipated that the Cd and Zn components may be released, and it could pollutethe surrounding water systems. Therefore, the treatment using limestone could signifi cantlyreduce the leaching of heavy metals from the contaminated paddy soil. It was also expectedthat the application of limestone to the paddy soil contaminated by heavy metals could beconsidered an economical and feasible way to reduce the releasing of pollutants aroundresidences and in the ecological system.
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