Seleção de espécies para fitorremediação de Bário sob condição de alagamento

Abstract

Increased exploratory activity and intensive oil and gas has greatly increased use of BaSO4 barium sulphate and therefore the amount of barium salt used as a densifying agent in oil well drilling mud, which in case of leakage, can affect environment. Given this paradigm, this study aimed to present and select plant species that have tolerance and ability to fitorremediar flooded environments contaminated with barium (Ba). The experiment was conducted in a factorial 10x6, represented by 10 species/varieties grown under five increasing levels of barium chloride BaCl2, but the zero dose (control), with three repetitions, totaling 180 experimental units, in a completely randomized design - DIC. The experiment lasted four months between april and august 2013. Ten species/varieties were pre-selected: two varieties of Oryza sativa (IRGA 424 and BRS. Tropical); Eleocharis interstincta; Brachiaria arrecta; Paspalum conspersum; Cyperus cf. papyrus, Nepholepsis cf. rivulares, Eleocharis acutangula 2, Eleocharis acutangula 1 and Typha domingensis. These were cultivated in pots containing 13 kg of soil and kept under flooded condition. During the phytoremediation test were performed biometric, physiological and chemical evaluations, including a quantification of Ba2+ extracted and accumulated in shoot and roots. Species that have excelled in the production of biomass in roots and shoots were C. cf. papyrus, T. domingensis and E. acutangula 1. Regarding the concentration of Ba mg g-1 , the P. conspersum and T. domingensis showing the highest levels. The Ba accumulation in shoots was higher in C. cf. papyrus, followed by T. domingensis, while the roots were markedly higher in T. domingensis. Generally the species most fitoacumularam Ba, were T. domingensis, C. cf. papyrus and E. acutangula 1. The different stages photochemical reported results heterogenic enough, but T. domingensis demonstrated considerable physiological resourcefulness. The species that showed increased tolerance and ability to extract and accumulate barium was T. domingensis. The C. cf. papyrus reported the largest fitoacumulação capacity in the shoot. The N. cf. rivularis showed high sensitivity the conditions employed in this test phytoremediation. T. domingensis presented the best xvi physiological parameters, presenting the most resistant species the conditions of flooding and barium toxicity, among species / varieties evaluated.