Comparative effects of several cyclodextrins on the extraction of PAHs from an aged contaminated soil

7 páginas.-- 3 figuras.-- 2 tablas.-- 52 referencias.-- Supplementary dataThe objective of the present study was to characterise the polycyclic aromatic hydrocarbons (PAHs) content of an aged contaminated soil and to propose remediation techniques using cyclodextrins (CDs). Four CDs solutions were tested as soil decontamination tool and proved more efficient in extracting PAHs than when an aqueous solution was used; especially two chemically modified CDs resulted in higher extraction percentages than natural β-CD. The highest extraction percentages were obtained for 3-ring PAHs, because of the appropriate size and shape of these compounds relative to those of the hydrophobic cavities of the CDs studied. A detailed mechanistic interpretation of the chemical modification of CDs on the extraction of the different PAHs has been performed, and connected with the role that the different hydrophobicities of the PAHs play in the extraction behaviour observed for the 16 PAHs, limiting their accessibility and the remaining risk of those PAHs not extractable by CDs. © 2013 Elsevier Ltd. All rights reserved.The authors thank to Dr. J.R. Gallego from the Universidad de Oviedo for providing the contaminated soil sample. Support from projects CTM2006-04626 and CTM2009-07335, Spanish Ministry of Science and Innovation (co-funded by Fondo Europeo de Desarrollo Regional, FEDER), are greatly appreciated. M.A. Sánchez-Trujillo acknowledges a research contract from CSIC (JAEPre 0800763) cofinanced by Fondo Social Europeo (FSE).Peer Reviewe

Decontamination of polycyclic aromatic hydrocarbons and nonylphenol from sewage sludge using hydroxypropyl-β-cyclodextrin and evaluation of the toxicity of leachates

11 páginas.-- 2 tablas.-- 3 figuras.-- 61 referenciasA decontamination technique based in cyclodextrin extraction has been developed to eliminate nonylphenol (NP) and 16 polycyclic aromatic hydrocarbons (PAHs; the US Environmental Protection Agency priority pollutants list) from sewage sludge. In a first step, PAHs and NP were characterised in six sludges to determine contamination levels according to limit values proposed by the European Union Sludge Directive draft. There were few variations in the total PAHs content with levels of 1.88 to 3.05 mg kg-1. Three-ring PAHs predominated, but fluoranthene and pyrene were also present. None of the sludge exceeded the PAHs limit proposed by the European Union's draft Directive. On the contrary, NP content in four of the six sludges was over the recommended limits of 50 mg kg-1 for NP ethoxylates. With the aim of obtaining NP values below the concentration limits proposed to use the sewage sludge as agricultural amendments, a preliminary study using hydroxypropyl-β-cyclodextrin (HPBCD) extractions as a decontamination technique was carried out. About 90 % of NP content was removed with only one extraction with HPBCD, whereas after three sequential extractions using an aqueous solution without HPBCD, the NP extraction percentage was less than 1 %. Simultaneously, PAHs extraction percentages obtained with HPBCD were also much higher than when aqueous solution was used, especially in the case of two- and three-ring PAHs. Finally, the potential environmental hazard of HPBCD leachates to aquatic organisms (Daphnia magna) was tested. These results indicate that the treatment of sewage sludge with cyclodextrin could allow their safe use as fertiliser in agriculture. © 2013 Springer-Verlag Berlin Heidelberg.Support from projects CTM2006-04626 and CTM2009-07335, Spanish Ministry of Science and Innovation (cofunded by Fondo Europeo de Desarrollo Regional, FEDER), are greatly appreciated. M.A. Sánchez-Trujillo acknowledges a research contract from Consejo Superior de Investigaciones Científicas (CSIC, JAEPre 0800763) cofinanced by Fondo Social Europeo (FSE).Peer Reviewe

Paleoecología y cultura material en el complejo tumular prehistórico de Castillejo del Bonete (Terrinches, Ciudad Real)

Castillejo del Bonete es un complejo tumular situado en el borde meridional de la Meseta Ibérica, ocupado en fechas calcolíticas y de la Edad del Bronce, vinculado a la Cultura de las Motillas. Materiales arqueológicos muy diversos han sido recuperados asociados a las arquitecturas del lugar (túmulos, corredores, potentes muros, etc.). Se presenta un avance de la investigación paleoecológica sobre las colecciones de carbón, polen y microvertebrados. Además se presentan cuentas de piedra y madera, colgantes de concha, material lítico, la colección cerámica, nuevas metalografías e industria metálica y botones de marfil. El conjunto de estas evidencias arqueológicas pone de manifiesto la celebración ritual de banquetes y ofrendas durante la Prehistoria Reciente en una cueva monumentalizada mediante túmulos en el interior de la Península Ibérica

Recuperación de suelos contaminados mediante el uso de ciclodextrinas

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Comparative mineralisation of pyrene in a spiked and aged soil by a pyrene-degrading bacterium isolated from a pahs-contaminated soil and effect of the presence of cyclodextrin

Póster 79, en la Sesión: Biodegradation and toxicity of POPs.-- Simposio celebrado del 24-28, junio, 2012, en Praga, República Checa.A pyrene-degrading bacterial strain E2BCU-2008-S8.3 was isolated from an aged PAHscontaminated soil from the North of Spain. The strain was identified as Achromobacter sp. by 16S rDNA gene sequence analysis technique. To screen for the ability of this bacterium to mineralise pyrene, the strain was cultured in a Tryptic Soy Broth medium diluted 20 times, inoculated at 24°C and exposed in triplicate to 166 Bq g-1 of soil of 14C-pyrene. In adition, 0.5 mg of nonradiolabeled pyrene was added to each culture.Peer reviewe

Recuperación de suelos contaminados mediante el uso de ciclodextrinas.

Actualmente, la contaminación de suelos, aguas sub- terráneas y aguas superficiales por compuestos hi- drófobos es una preocupación importante en todo el mundo. Muchos de estos compuestos son una ame- naza para la salud humana y para el medio ambiente. El suelo es el principal sumidero de la mayoría de es- tos contaminantes orgánicos. La contaminación del suelo puede ser causada por accidentes industriales (fugas y derrames subterráneos) y actividades antro- pogénicas (tratamientos agroquímicos, forestales e in- cendios agrícolas y combustibles) originando una contaminación a largo plazo en el medio ambiente (Wong et al., 2009).Peer Reviewe

Recovery of polycyclic anthracene and pyrene from spicked and aged soils by using hydroxipropyl-beta-cyclodextrin

Polycyclic aromatic hydrocarbons (PAHs) are considerd to be prority pollutants in the environment and are of major concern due to their recalcitrance and strong mutagenic/carcinogenic properties. It has been observed that as soil-pollutant contact time increases, pollutant bioavailability and extractability decreases. This phenomenon has been termed "ageing". Cyclodextrins (CDs) appeared as prormising complexing agents to mobilize hydrophobic aromatic pollutints in soils while minimizing environmental impact. In this work we examined the potential of HPBCD to enhance the extraction of the PAHs Pyrene (PYR) and Anthracene (ANT) from spicked and aged soils.Peer reviewe

Recovery of polycyclic aromatic hidrocarbons from spiked and aged soils by using hydroxypropil-β- cyclodextrin (HPBCD)

Assessment of the hazard of toxic chemicals in soil are made without concern the possibility that bioavailablity may change with the lime. Aging refers to the increased contact time between a chemical and soil particles, which can allow a compound to become more strongly associated with soil components over time.Peer reviewe

Effect of contact time and the use of hydroxypropyl-β-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils

11 páginas.-- 4 figuras.-- 4 tablas.-- 60 referencias.-- 3 archivos docx (1 figura y 2 tablas) de material suplementario.Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils were carried out and correlated to their removal from aged contaminated soils using aqueous solutions in the absence and in the presence of hydroxypropyl-β-cyclodextrin (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged contaminated soils due to its initial adsorption onto the mineral and amorphous soil organic matter (SOM) domains, sites of lower binding energy from which, due to its small size, it could spread towards the condensed SOM as the contact time increased. Therefore, FLU will not be easily desorbed from aged contaminated soils due to physical entrapment mechanisms, even when using HPBCD as extractant, presenting FLU low risks to the environment. On the contrary, FLT was extracted from aged soils in the presence of HPBCD in solutions to a much greater extent than in its absence. Due to its more hydrophobic character FLT sorption in soils was relatively quicker, remaining more or less fixed on hydrophobic sites of the organic matter (OM) with different energies, and therefore the amount of FLT extracted was almost constant for different ageing times. During extraction experiments, the influence of the OM quality of the soils was also highlighted because an inverse proportionality between OM content of soil and extractability of sorbed FLT was observed. It was concluded that soils with lower OM content that had more diagenetically processed OM could block the extraction of FLT more effectively than soils with higher OM content that are less humified. This indicates the need to use not only adsorption-desorption data in contaminant fate and transport models, but also extraction studies in aged contaminated soils and other complementary analytical approaches when assessing soil contamination-related risks.Financial support for project CTM2009-07335 from Spanish Ministry of Science and Innovation (cofounded by Fondo Europeo de Desarrollo Regional, FEDER), is greatly appreciated. M.A. Sánchez-Trujillo acknowledges a research contract from CSIC (JAEPre 0800763) cofinanced by Fondo Social Europeo (FSE).Peer Reviewe