The DTPA-extractable heavy metals in tropical soils treated with lime materials
1997
Salam, A.K. (Institut Pertanian Bogor (Indonesia)) | Djuniwati S. | Sarno | Sriyani, N. | Novpriansyah, H. | Septiana, A. | Putera, H.D.
Soils are prone to pollution by heavy metals from various sources, but their capacities to immobillize heavy metals are limited. This research was intended to study the influence of some lime materials on the extractability of some heavy metals in soils. Tropical soils (Oxisols, Ultisols and Alfisols), collected from Lampung, Indonesia, were used. The soil sample (air dry, 2-mm-sieved) were spiked with standard solution containing Cu, Cd, Zn, and Mn and treated independently with lime materials CaCO3, Ca(OH)2, or CaMg(CO3)2 to bring the soils, pH about 2 units higher. The soluble heavy metal were extracted with DTPA and determined with flame AAS after an 8-week incubation at the soils field moisture capacities. The results showed that in the soils not spiked with heavy metals at all time, this significantly decreased the extractable Cu, Cd, Zn, and Mn, in a negative relation with the changes in soil pHs, increased with lime addition. The extractable heavy metals in the soils spiked with heavy metals was also clearly observed. The extractable heavy metals were generally higher in soils treated with CaMg(CO3)2 than in soils treated CaCO3 or Ca(OH)2 probably because of the effect of Mg ions in displacing the metals cations from soil adsorption surfaces. The degree of recovery of heavy metals suggested that parts of the heavy metals added were strongly adsorbed by soils. Based on the percent recovery values, the order of the soil adsorption capacities with respect to Cu, Cd, and Zn followed the order of: Alfisols Oxisols Ultisols. The soil preference toward the heavy metals generally followed the order of: Cu Cd Zn
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