Ameliorants to immobilize Cd in rice paddy soils contaminated by abandoned metal mines in Korea.
The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg⁻¹) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils.
Department of Biological Environment, Kangwon National University, Chuncheon, Korea.
Yong Sik
YS
Ok
Sung-Chul
SC
Kim
Dong-Kuk
DK
Kim
Jeffrey G
JG
Skousen
Jin-Soo
JS
Lee
Young-Wook
YW
Cheong
Su-Jung
SJ
Kim
Jae E
JE
Yang
D002104:Cadmium / Q000032:analysis / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007501:Iron / Q000737:chemistry; D008906:Mining; D012275:Oryza; D010087:Oxides / Q000737:chemistry; D056910:Republic of Korea; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*
D017610:Calcium Compounds; D010087:Oxides; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; C016538:lime; D007501:Iron