Assessment of single extraction methods for the prediction of bioavailability of metals to Brassica juncea L. Czern. (var. Vaibhav) grown on tannery waste contaminated soil.

Various single extractant (DTPA, EDTA, NH(4)NO(3), CaCl(2), and NaNO(3)) was used to evaluate the bioavailability of heavy metals from tannery wastewater contaminated soil and translocation of metals to the plant of Brassica juncea L. Czern. (var. Vaibhav). The extraction capacity of the metals was found in the order: EDTA>DTPA>NH(4)NO(3)>CaCl(2)>NaNO(3). Cluster analysis between different extractants showed close relationship between DTPA, CaCl(2), NH(4)NO(3) except EDTA and NaNO(3), which showed dispersed relationship. Principal components analysis (PCA) applied to metals extracted with EDTA showed different grouping of metals (i) Na, Co, Pb, Ni and (ii) K, Mn, Zn, Cr, in the loading plot which showed similar availability from contaminated soil. PCA applied on metals accumulation data in the plants also exhibited different grouping of variables (i) Cu, Co, Ni, Cd and (ii) Mn, Zn, Pb, Fe showed almost similar accumulation pattern in the plants. The data displayed positive loading for Mn and negative loading for Cr with PC(2). Cd and Zn have shown high loadings in PC(1) and PC(2), respectively. The translocation of most of the tested metals (Pb, Mn, Cd, Ni, Fe) in the shoot of the plant was found better except Cr, Cu, Co and K. The correlation analysis between different extractable metals and metal accumulation in the shoot of the plant showed significant positive correlation with Pb and Cr. Overall, extraction capacity and cluster analysis augmented that EDTA was found suitable extractant for tannery wastewater contaminated soil to B. juncea.