Health recovery of soil polluted with marble effluents by the inoculation of Mn-tolerant bacteria

Abstract

Marble industry is one of the pillars of modern buildings and structures but marble industry’s effluents, organic pollutants and heavy metals are affecting natural ecosystem. In present work, fourteen bacteria were isolated from the rhizo-surface soil, receiving marble industry effluent from Hattar industrial area. The soil was heavily polluted with manganese (Mn). Among isolated strains <i>Rothia</i> sp, <i>Methylobacterium</i> sp, <i>Pantoea eucrina</i> and <i>Bacillus safensis</i> were found strong phosphate solublizer, indole acetic and organic acids producers. <i>B. safensis</i> and <i>P. eucrina</i> exhibited strong tolerance at 1750 ppm and 2000 ppm of MnSO₄; and were applied alone and in consortium to naturally polluted soil collected from Hattar in a green house on maize (<i>Zea mays</i> L.). Consortium + recommended dose of fertilizers (RDF) and different concentrations of MnSO₄ improved 12-25% of plant biomass. Plants grown in naturally polluted soil of marble industry exhibited 50-60% increases in growth indices in single inoculation, and these increases were 65% in consortium application. Plants grown in naturally polluted soil exhibited 30-45% increases in physiological indices. It is inferred that Mn stressed soil may be reclaimed by the application of <i>B. safensis</i> and <i>P. eucrina</i>.