Potencial de espécies vegetais para fitorremediação de um solo contaminado por arsênio

• Autor(a) principal: Melo, Roseli Freire de
• Data de Publicação: 2006
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1590
• topic: Arsenato; Fitoextração; Fitoestabilização; Arsenic; Phytoextraction; Phytoremediation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

Arsenic is found in the nature associated with ores from silver, gold, antimonium, cobalt and nickel. Intoxication and death in thousands persons caused by arsenic were related in different countries of the word. In Brazil there is high concentrations areas of this metalloid at Quadrilátero Ferrífero of Minas Gerais State, at delta of Amazonas river and Santana in Amapá State, among others. Considering the impact that arsenic may cause on the environment it is very important to set techniques to remediate arsenic high content areas. This work had the aim to evaluate the potential of different species of legumes herbaceous - velvetbean (Stizolobium aterrimum Piper & Tracy), jack bean (Canavalia ensiformis (L.)) and crotalaria (Crotalária spectabilis Roth.), of foragers herbaceous - townsville stylo (Stylosanthes humilis), forage peanuts (Arachis pintoi), oat (Avena strigosa Schreb), and ryegrass (Lolium multiflorum Lam.), of legumes shrubs - jack bean (Cajanus cajan L.), sesbania (Sesbania virgata Cav.), leucena (Leucaena leucocephala Lam. (De Witt)), and eucalyptus species - Eucaliptus grandis Hill, E. cloeziana (F. Muell), E. urophylla (S.T. Black), Corymbia citriodora (Hill & Johnson) (Eucalyptus citriodora Hook) to phytoremediation programs of arsenic contaminated areas. Samples of Red-Yellow Latossol were incubated with different doses of As: 0; 50; 100 and 200 mg dm-3 to herbaceous and shrubs species and 0,0; 50; 100; 200 e 400 mg dm-3 to eucalyptus species. These doses resulted in 0,0; 12,9; 26,8; 58,7 e 128,8 mg dm-3 of available arsenic by Mehlich-3, respectively. Sodium arsenate (Na2HAsO4+7H2O) was the As source used for all experiments. After the incubation time herbaceous and shrubs species were seeded and to eucalyptus species the seedlings transplantated two months of seedling. The macro and micronutrients fertilizations were done after the seeded or transplantation. After sixty five days to herbaceous and 90 days to shrubs and eucalyptus species of seeding and transplantation, plants were evaluated to height, diameter and root and shoot biomass. Arsenic content in young, intermediated, and old leaves, steam and roots, and As-translocation index were determined. By regression analysis we estimated the values of soil critical available arsenic (TC) that reduced 50% of biomass production. Species showed different behavior to arsenic tolerance: velvetbean, sesbania, leucena, ryegrass and E. grandis did not show As-toxic morphologic symptoms, as injuries in leaves, and showed higher soil TC values than others species. High As content in roots from these species suggests the action of different mechanisms of accumulation and translocation of As in the shoot tissues. Jack bean, jack bean, oat forager and E. cloeziana showed injuries in bottom leaves when exposed to the higher dose of As, showing potential as bioindicators plants of arsenic-contaminated soils. On the other hand, species as velvetbean, ryegrass, forage peanuts, townsville stylo and E. urophylla showed high Astolerance with potential to arsenic-phytostabilization plants. E. grandis, crotalária e Corymbia citriodora showed potential to be used as As-phytoextraction plants. Nevertheless, more conclusive works, in field conditions and more exposition time, to set the potential of these species must be done.