Change of Cadmium Availability by Soil Amendments in the Paddy Soils.

Heavy metals from abandoned mine can be released in adjacent agricultural field by runoff and leaching after rainfall. Introduced heavy metals are accumulated in crops and eventually have adverse effect on human health. Therefore, increased attention has been made to remediate heavy metal contaminated agricultural field in Korea. The main purpose of this research was to evaluate reduction of bio-available heavy metals with lime treatment in the paddy soils. Cadmium contaminated soil (11.06 mg kg^-1) was treated with varied amount of lime (1~5%) for 7 days and fractionation analysis (adsorbed, carbonate, reducible, organic, residuals) was conducted. The result of fractionation analysis showed that about 67~77% of adsorbed fraction of cadmium (4.34 mg kg^-1 of initial concentration) was decreased and 59~69% of carbonate fraction (1.76 mg kg^-1 of initial concentration) was increased depending on mixed lime amount after 7 days. Also, reducible fraction of cadmium (3.74 mg kg^-1 of initial concentration) was increased 32~42% compared to control. The rest of fraction, organic and residuals was fairly constant. This result indicated that bio-available fraction of cadmium was converted to non-bioavailable fraction with lime treatment. Since bio-available fraction of cadmium is decreased with lime treatment, the possibility of cadmium transfer from soil to crop will also be decreased.