Evaluation of Chelating Agents as Heavy Metals Extractants in Agricultural Soils under Threat of Contamination
Kocialkowski W. Z., Diatta J. B., Grzebisz W.
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Department of Agricultural Chemistry, Wojska Polskiego 71 F, 60-625, Poznan, Poland
Pol. J. Environ. Stud. 1999;8(3):149–154
Four chelating agents: HEDTA, EDTA, EGTA, and NTA added to 1M NH4OAc were compared in order to assess their ability for heavy metals extraction. NH4OAc alone revealed the lowest efficiency of metals extraction than the remaining chelate enriched extractants for extracting Cu, Zn, Mn, and Pb. Among chelating agents such as EDTA and EDTA, solutions of NH4OAc+EDTA and NH4OAc+HEDTA were the most effective extractants. The percentage share of extracted Cu, Zn, Mn and Pb varied from 32% to 42% of their total content, irrespective of the added chelating agents and for NH4OAc from 13% to 20% for all metals. Minimizing the direct influence of the parameters set (i. e. extractant concentration, pH, soil/extractant ratio, extraction time) one may suggest that the slight differentiation in the amounts of extracted metals is probably a matter of chelating agent feature. Correlations between amounts of all extracted metals and soil properties were relatively low, irrespective of the extractant used. This state may be explained by a prevailing anthropogenic origin of these metals (mainly Cu and Pb) in studied soils.