Degradação microbiana de ácido cítrico em solo contaminado por chumbo

Abstract

The bioremediation studies have intensified in recent years, mainly due to the increase of areas contaminated by human activities. The low solubility of natural Pb ion in the soil, appears as a major impediment programs bioremediation. Thus the use of chelating presents as an alternative to maintain high levels of this metal in the soil solution. Thus, the present study aimed to evaluate laboratory conditions on the ability of soil microbes to decompose the citric acid used as complexing metal ions in the soil. The global activity microbial was determined by the ability of C-CO₂ soil in 0.1 M NaOH solution under a continuous flow system of air. We used a completely randomized design with three replications. Treatments were arranged in a factorial 3 x 2 x 4 + 3, corresponding to three state soil (contaminated, contaminated subjected to liming on the field and uncontaminated soil of native forest) two formulations of citric acid (pure for analysis - PA and commercial), four doses of citric acid (10, 20, 40 and 80 mmol dm-3) and three witnesses (soil situations without citric acid), split plot in reading times (4, 8, 12, 24 , 48, 96, 144, 240, 336, 432, 528, 624 and 720 h), with three replications. The soil contaminated with Pb had lower microbial activity. The largest stimuli to soil microorganisms occurred in the presence of citric acid, P.A. There was no response of soil microbes to correct the pH, when applying citric aci