334 POTENTIAL OF THREE LEGUME SPECIES FOR PHYTOREMEDIATION OF ARSENIC CONTAMINATED SOILS 1 Luiz E. Dias 2 , Roseli F. Melo, Jaime W. V. Mello, Juraci. A. Oliveira, and W. L. Daniels Abstract. Phytoremediation strategies utilize plants to decontaminate or immobilize soil pollutants. Among soil pollutants the metalloid arsenic (As) is the one of primary concern. Elevated soil As results from anthropogenic activities such as use of pesticides (herbicides and fungicides), use of certain fertilizers, metal mining, iron and steel production, coal combustion, and from co- production during natural gas extraction. This study evaluated the potential of pigeon pea (Cajanus cajan), wand riverhemp (Sesbania virgata), and lead tree (Leucaena leucocephala) for phytoremediation of soils polluted by As. Soil samples were placed in plastic pots, incubated with different As doses (0, 50, 100 and 200 mg dm -3 ) and then sown with seeds of these three species. Ninety days after sowing, the plants were evaluated for height, collar diameter and dry matter of young, intermediate and basal leaves, stems and roots. Arsenic concentration was determined in different aged leaves, stems and roots to establish the translocation index (TI) between plant roots and aerial plant components. The evaluated species showed distinctly different characteristics with respect to As tolerance, since the lead tree and wand riverhemp were significantly more tolerant than pigeon pea. High As levels found in wand riverhemp roots suggest the existence of an effective mechanism of accumulation and compartmentalization in order to reduce As translocation to aboveground tissues. Pigeon pea is a sensitive species and could serve as a potential bioindicator plant, whereas the other two species have potential for phytoremediation programs in As polluted areas. However, further studies are needed with longer exposure times in actual field conditions to reach definitive conclusions on the relative phytoremediation potentials on these species. Additional Key Words: remediation, decontamination, Cajanus cajan, Sesbania virgata, Leucaena leucocephala. _______________________________ 1 Paper was presented at the 2009 National Meeting of the American Society of Mining and Reclamation, Billings, MT, Revitalizing the Environment: Proven Solutions and Innovative Approaches May 30 – June 5, 2009. R.I. Barnhisel (Ed.) Published by ASMR, 3134 Montavesta Rd., Lexington, KY 40502. 2 L. E. Dias and J. W.V. Mello, Associate Professors, CNPq grant holders, Soil Dep. Universidade Federal de Viçosa – UFV, 36571-000, Viçosa-MG Brazil., R. F. Melo, Agronomist, Researcher, Agric. Res. Center of the Semi-Arid Tropics (EMBRAPA- CPATSA), P.Box 23, 56302-970- Petrolina-PE, Brazil. J. A. Oliveira, Assoc. Prof. Biology Dep., UFV; W. L. Daniels, Professor, Dep. of Crop and Soil Environmental Sciences, Virginia Tech, Blacksburg, VA 24061. Proceedings America Society of Mining and Reclamation, 2009 pp 334-347 DOI: 10.21000/JASMR09010334