Document Type : Research Paper
Authors
Department of soil science, Faculty of agriculture, Bu-Ali Sina University, Hamedan, Iran
Abstract
Phytoremediation, a relatively new and an environmentally friendly technology, is the use of plants for the removal of pollutants from contaminated soils. A greenhouse pot experiment was conducted to evaluate the heavy metal (lead, zinc and copper) accumulation of Zea mays, Helianthus annuus, Cannabis sativa and Brassica napus. Plants were grown in two soils; one from Ahangaran Lead-Zinc Mine, and the other from an agricultural soil. The shoot and root dry weight, heavy metal concentrations in shoot and root, translocation factor (TF), Enrichment factor (EF) and heavy metal fractions were measured. The distribution of different lead and zinc fractions were revealed the following order: residual > carbonate > organic > exchangeable. However, for copper the order was as residual > organic > carbonate > exchangeable. The minimum lead concentration (25.50 mg kg-1) was observed in Z. mays shoot tissue and the maximum (301.30 mg kg-1) in C. sativa shoot tissue. Lead TF ranged from 0.72 to 0.96 and decreased in the following order: H. annus > C. sativa > B. napus > Z. mays. Zinc TF changed from 0.70 to 0.99 and as H. annus > Z. mays> C. sativa > B. napus, and copper TF turned from 0.49 to 1.83 and as H. annus > C. sativa > B. napus > Z. mays. The EF value of lead varied from 0.24 for Z. mays to 0.48 for C. sativa, from 0.75 for Z. mays to 1.01 for H. annus regarding to zinc, and the copper EF value ranged from 0.39 for C. sativa to 1.42 in H. annus. Although H. annus and C. sativa accumulated lead more than Z. mays and B. napus, none of the plants was hyperaccumulator for lead, zinc or copper.
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