Remediation Technologies for Organochlorine-Contaminated Sites in Developing Countries

Bezama, Alberto; Navia, Rodrigo; Mendoza, Gonzalo; Barra, Ricardo

doi:10.1007/978-0-387-73163-6_1

Cited by 3 publications

(3 citation statements)

References 76 publications

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“…In this respect, maize stalks might be really valuable [14,15]. The reduced PCB bioavailability stemming from their high tendency to become adsorbed to organic matter colloids [16] has been shown to be partially counteracted by the use of synthetic [17] or biogenic [18,19] mobilizing agents (MAs).…”

Section: Introductionmentioning

confidence: 99%

Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

et al. 2012

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BackgroundSeveral species belonging to the ecological group of white-rot basidiomycetes are able to bring about the remediation of matrices contaminated by a large variety of anthropic organic pollutants. Among them, polychlorobiphenyls (PCBs) are characterized by a high recalcitrance due to both their low bioavailability and the inability of natural microbial communities to degrade them at significant rates and extents. Objective of this study was to assess the impact of a maize stalk-immobilized Lentinus tigrinus CBS 577.79 inoculant combined with soybean oil (SO), as a possible PCB-mobilizing agent, on the bioremediation and resident microbiota of an actual Aroclor 1260 historically contaminated soil under unsaturated solid-phase conditions.ResultsBest overall PCB depletions (33.6 ± 0.3%) and dechlorination (23.2 ± 1.3%) were found after 60 d incubation in the absence of SO where, however, the fungus appeared to exert adverse effects on both the growth of biphenyl- and chlorobenzoate-degrading bacteria and the abundance of genes coding for both biphenyl dioxygenase (bph) and catechol-2,3-dioxygenase. A significant (P < 0.001) linear inverse relationship between depletion yields and degree of chlorination was observed in both augmented and control microcosms in the absence of SO; conversely, this negative correlation was not evident in SO-amended microcosms where the additive inhibited the biodegradation of low chlorinated congeners. The presence of SO, in fact, resulted in lower abundances of both biphenyl-degrading bacteria and bph.ConclusionsThe PCB depletion extents obtained in the presence of L. tigrinus are by far higher than those reported in other remediation studies conducted under unsaturated solid phase conditions on actual site soils historically contaminated by Aroclor 1260. These results suggest that the bioaugmentation strategy with the maize stalk-immobilized mycelium of this species might be promising in the reclamation of PCB-contaminated soils. The addition of SO to matrices contaminated by technical PCB mixtures, such as Aroclor 1242 and Delor 103 and characterized by a large preponderance of low chlorinated congeners, might not be advisable.

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Section: Introductionmentioning

confidence: 99%

Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

et al. 2012

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“…An additional design concept to reduce the amount of washing solution for the remediation project is the implementation of an adsorption step to clean the spent washing solution from PCBs and therefore making it suitable for reuse (Bezama et al, 2008). A further step to consider is the implementation of thermal desorption of the washed soils, coupled with condensation of the generated gases, thus recovering n-hexane and reducing the hazardous level of the resulting waste.…”

Section: Discussionmentioning

confidence: 99%

“…In a previous study, Bezama et al (2008) presented a theoretical management concept for the remediation of soils contaminated with chlorinated hydrocarbons based on soil washing. A critical aspect of the concept is the selection of an appropriate washing solution, especially when dealing with organic pollutants.…”

Section: Introductionmentioning

confidence: 99%

Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil

et al. 2013

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The goal of this work was to evaluate a washing process that uses organic solutions for polychlorinated biphenyl (PCB)-contaminated soil, and includes an ultrasound pre-treatment step to reduce operational times and organic solvent losses. In a preliminary trial, the suitability of 10 washing solutions of different polarities were tested, from which three n-hexane-based solutions were selected for further evaluation. A second set of experiments was designed using a three-level Taguchi L27 orthogonal array to model the desorption processes of seven different PCB congeners in terms of the variability of their PCB concentration levels, polarity of the washing solution, sonication time, the ratio washing solution/soil, number of extraction steps and total washing time. Linear models were developed for the desorption processes of all congeners. These models provide a good fit with the results obtained. Moreover, statistically significant outcomes were achieved from the analysis of variance tests carried out. It was determined that sonication time and ratio of washing solution/soil were the most influential process parameters. For this reason they were studied in a third set of experiments, constructed as a full factorial design. The process was eventually optimized, achieving desorption rates of more than 90% for all congeners, thus obtaining concentrations lower than 5 ppb in all cases. The use of an ultrasound-assisted soil washing process for PCB-contaminated soils that uses organic solvents seems therefore to be a viable option, especially with the incorporation of an extra step in the sonication process relating to temperature control, which is intended to prevent the loss of the lighter congeners.

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Biological Aspects Involved in the Degradation of Organic Pollutants

Díez

2010

J. Soil Sci. Plant Nutr.

135

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Worldwide use of pesticide has increased dramatically during the last two decades. As a consequence, pesticide residues and their transformation products are frequently found in groundwater and surface waters. This review summarizes information about polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), some chlorophenols; it mainly empathizes on pesticides, their incorporation into the environment, microorganisms involved in their degradation and, some physicochemical aspects of pesticides behavior in soils. Details about residues of pesticides in groundwater and superficial water found in some foreign countries and in Chile are reported, as well. The fungal degradation of organic pollutants (xenobiotics) is considered as an effective method to remove these pollutants from the environment by a process which is currently known as bioremediation. Therefore, the degradation of pesticides by soil microorganisms with particular attention to white-rot fungi is also addressed. Finally, a simple and effective system (biobed) to minimize environmental contamination from pesticide manipulation, especially when filling the spraying equipment, a typical point source of contamination, is presented here.

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Remediation Technologies for Organochlorine-Contaminated Sites in Developing Countries

Cited by 3 publications

References 76 publications

Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil

Biological Aspects Involved in the Degradation of Organic Pollutants

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