Ecology, Environment and Conservation Paper

SUITABILITY OF EXTRACTANTS FOR PREDICTING AVAILABILITY OF CADMIUM IN INCEPTISOL, ALFISOL AND VERTISOL

Asha Sahu, S.K. Singh Nisha Sahu and M.C. Manna

Abstract

Heavy metals are potentially toxic to human life and the environment. Various extraction procedures were Employed for measuring extractable concentrations of potential toxic elements in soil. In a greenhouse pot experiment, three taxonomically different soil orders viz. Typic Ustochrepts (alluvial soil), Typic Rhodustalfs (red soil) and Entic Chromusterts (karail soil) with pH ranging from 5.7 to 8.2 were used. These soils were artificially spiked with different Cd levels (0, 5, 10, 25, 50 and 100 mg Cd kg-1). After one month of incubation, extractability of Cd in soils was compared by six extractants: DTPA, AB-DTPA, Mehlich 1, Mehlich III, 0.1 N HCl and CH3COOH to predict Cd bioavailability in soils. African marigold (Tagetes erecta L.) was used as test species. Suitability of these extractants in relation to plant tissue concentration and uptake of Cd were also investigated. Extractability of Cd in soils varied depending on extractants used. It was found that 0.1 N HCl extracted the largest portion of Cd irrespective of soil types. Correlation study of Cd content in soil extracted by different extractants with plant tissue concentration and uptake revealed that best extractant was AB DTPA in Typic Ustochrepts, Mehlich 1 in Typic Rhodustalfs and CH3COOH in Entic Chromusterts.