Autori: LÃCÃTUŞU Anca-Rovena, Diana COCÂRÞÃ, Radu LÃCÃTUŞU
Editorial: ISSN 1842-4090 , Carpathian Journal of Earth and Environmental Sciences, 8(1), p.59 - 70 , 2013.
The paper presents the results of bioremediation experiment conducted in order to determine the effectiveness of this method for the decontamination of a soil historically contaminated with heavy metals and artificially controlled with two of the most aggressive group of organic pollutants: hydrocarbons from crude petroleum and polychlorinated biphenyls from transformer oil. The experiment followed how a heavy metals polluted soil respond to innoculation with heterotrophyc bacteria selected for their ability to metabolize the petroleum hydrocarbons and / or polychlorinated biphenyls, the effects exerted by heavy metal pollution on soil capacity to initiate and supports its own decontamination mechanisms. To implement full-scale bioremediation, the soil from Copşa Micã, historically contaminated with heavy metals, after it has been excavated was transported and disposed on a waterproofed platform in 0.2 m thickness layers, which were controlled contaminated with crude oil and transformers oil, resulting four experimental variants to whom technological elements of the bioremediation process were applied. Monitoring soil quality parameters: pH, organic carbon content, total nitrogen, C/N ratio, mobile phosphorus and potassium contents and the soil loading degree with inorganic pollutants, heavy metals (Zn, Cu, Fe, Mn , Pb, Ni, Cr, Cu, Cd) and organic: total petroleum hydrocarbons (THP) and polychlorinated-biphenyls (PCBs) was performed at 1 month, 3, 5 and 10 months after controlled pollution application. The data obtained have been interpreted dynamically, and comparisons were made between the four experimental variants. Biodegradation efficiency analysis of the two categories of pollutants (TPH and PCBs) applied to soil by controlled pollution, shows that ex situ bioremediation method is definitely favorable for hydrocarbons polluted soil remediation. The data obtained until 10 months from when controlled pollution of soil it was carried out, although representing a favorable method for bioremediation even in the case polychlorinated-biphenyls pollution are not yet defining and conclusive. Well known molecular recalcitrance of these compounds prevents the attack of microorganisms and their inherent toxicity affects the adaptability and multiplication of microorganisms with the ability to break-down the phenolic nuclei, and initiate biodegradation.
Cuvinte cheie: ex situ bioremediation, soil, heavy metals, petroleum hydrocarbons, polychlorinated biphenyls