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Letter to the Editor.

Letter to the Editor of the European Journal of Soil Science as a reaction to the Russell Review by Phillipe Baveye “Bypass and hyperbole in soil research: worrisome practices critically reviewed through examples” and to his follow‐up Invited Opinion paper “Bypass and hyperbole in soil research: a personal view on plausible causes and possible remedies” and the subsequent Letter to the Editor by Johan Bouma “Soil challenges beyond publication issues”

La baja biodisponibilidad del hexaclorociclohexano (HCH) afecta a la efectividad de procesos de biorremediación de suelos contaminados por HCH. Para aumentar la solubilidad aparente del HCH y potenciar su biodisponibilidad, se estudió el efecto de la acción micelar de una gran variedad de líquidos iónicos con actividad surfactante (i.e. Surface-Active Ionic Liquids o SAILs) y surfactantes convencionales sobre la solubilidad de HCH. Se prepararon disoluciones de SAILs/surfactantes y HCH (a una concentración ca. 10 veces su límite de solubilidad) utilizando dos concentraciones distintas de SAILs/surfactantes (siempre >CMC). Los resultados varían según el isómero de HCH, el SAIL/surfactante y la concentración utilizada. De forma adicional, se estudió la ecotoxicidad de los SAILs/surfactantes en dos especies vegetales. Este estudio demuestra la potencialidad de los SAILs y surfactantes para su aplicación en biorremediación de suelos contaminados por HCH y propone varios SAILs para futuras investigaciones., The low bioavailability of hexachlorocyclohexane (HCH) affects the effectiveness of bioremediation processes of HCH-contaminated soils. The effect of the micellar action of a variety of surfactant-active ionic liquids (i.e. SAILs) and conventional surfactants on the apparent solubility of HCH and its bioavailability was studied. Solutions of SAILs/surfactants and HCH (at a concentration ca. 10 times its solubility limit) were prepared using two different concentrations of SAILs/surfactants (always >CMC). The results varied according to the HCH isomer, the SAIL/surfactant and the concentration used. Additionally, the ecotoxicity of SAILs/surfactants was studied in two plant species. This study demonstrates the potential of SAILs and surfactants for their application in bioremediation of HCH-contaminated soils and proposes several SAILs for future research.

The application of an effective and sensitive analytical method to determine soil contaminants is a crucial step in the monitoring and remediation processes. In the present work, we optimized the analysis of volatile organic compounds (VFOC) commonly present in fuel: oxygenates (FO-MTBE and ETBE-) and monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene (BTEX). Headspace (HS) and headspace-solid phase microextraction (HS-SPME) were optimized in water samples, and validated for contaminated soils, using artificially spiked soils. Contaminants were identified and quantified by gas chromatography coupled to mass spectrometry (GC/MS). Matrix effect correction with surrogate standards resulted essential when analyzing soil samples, especially when the sample exerted a strong sorption on the contaminants., A aplicação de um método analítico eficaz e sensível para determinar contaminantes orgânicos do solo e da água é um passo essencial durante os processos de monitorização e recuperação ambiental. No presente trabalho optimizou-se a análise de alguns compostos orgânicos voláteis que surgem, usualmente, nos combustíveis: compostos oxigenados (FO-MTBE e ETBE-) e hidrocarbonetos monoaromáticos tais como benzeno, tolueno, etilbenzeno e xileno (BTEX). As metodologias de extracção headspace (HS) e microextracção em fase sólida em modo headspace (HS-SPME) foram otimizadas em amostras de água e validadas para amostras de diferentes solos contaminados artificialmente. Os contaminantes orgânicos foram identificados e quantificados por cromatografia gasosa associada a espectrometria de massa (GC/MS). A correção do efeito da matriz com padrões surrogate foi essencial para a análise das amostras de solo, especialmente em solos que apresentavam uma forte adsorção dos contaminantes., La aplicación de metodologías analíticas sensibles y efectivas para la determinación de los contaminantes del suelo es una etapa crucial para la realización de experimentos de monitorización y remediación. En el presente trabajo, se optimizó el análisis de compuestos orgánicos volátiles (VFOC) comúnmente presentes en combustibles: incluyendo compuestos oxigenados (FO-MTBE y ETBE-) y hidrocarburos monoaromáticos, tales como benceno, tolueno, etilbenceno y xileno (BTEX). Los métodos de extracción en headspace (HS) y microextracción en fase sólida en headspace (HS-SPME) fueron optimizados para aguas contaminadas y después validadas para suelos, utilizando muestras contaminadas de forma artificial. La corrección del efecto matriz con estándares tipo surrogate fue esencial para el análisis de muestras de suelos, especialmente para aquellas que ejercían una fuerte adsorción sobre los contaminantes.

The application of an effective and sensitive analytical method to determine soil contaminants is a crucial step in monitoring and remediation processes. In the present work, we optimized the analysis of volatile organic compounds (VFOC) commonly present in fuel: oxygenates (FO-MTBE and ETBE-) and monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene and xylene (BTEX). Headspace (HS) and headspace-solid phase microextraction (HS-SPME) were optimized in water samples, and validated for contaminated soils, using artificially spiked soils. Contaminants were identified and quantified by gas chromatography coupled to mass spectrometry (GC/MS). Matrix effect correction with surrogate standards resulted essential when analyzing soil samples, especially when the sample exerted a strong sorption on the contaminants, La aplicación de metodologías analíticas sensibles y efectivas para la determinación de los contaminantes del suelo es una etapa crucial para la realización de experimentos de monitorización y remediación. En el presente trabajo, se optimizó el análisis de compuestos orgánicos volátiles (VFOC) comúnmente presentes en combustibles: incluyendo compuestos oxigenados (FO-MTBE y ETBE-) e hidrocarburos monoaromáticos, tales como benceno, tolueno, etilbenceno y xileno (BTEX). Los métodos de extracción en headspace (HS) y microextracción en fase sólida en headspace (HS-SPME) fueron optimizados para aguas contaminadas y después validadas para suelos, utilizando muestras contaminadas de forma artificial. La corrección del efecto matriz con estándares tipo surrogate fue esencial para el análisis de muestras de suelos, especialmente para aquellas que ejercían una fuerte adsorción sobre los contaminantes, A aplicação de um método analítico eficaz e sensível para determinar contaminantes orgânicos do solo e da água é um passo essencial durante os processos de monitorização e recuperação ambiental. No presente trabalho optimizou-se a análise de alguns compostos orgânicos voláteis que surgem, usualmente, nos combustíveis: compostos oxigenados (FOMTBE e ETBE-) e hidrocarbonetos monoaromáticos tais como benzeno, tolueno, etilbenzeno e xileno (BTEX). As metodologias de extracção headspace (HS) e microextracção em fase sólida em modo headspace (HS-SPME) foram otimizadas em amostras de água e validadas para amostras de diferentes solos contaminados artificialmente. Os contaminantes orgânicos foram identificados e quantificados por cromatografia gasosa associada a espectrometria de massa (GC/MS). A correção do efeito da matriz com padrões surrogate foi essencial para a análise das amostras de solo, especialmente em solos que apresentavam uma forte adsorção dos contaminantes

Soil contamination with fuel derived organic compounds is a problem principally caused by emissions and residues from the petrochemical industry, traffic accidents, and accidental leaks in pipelines or in underground fuel storage tanks. Soils contaminated with fuels have a high environmental risk, since they can contaminate other environmental compartments, with the inherent risks for human health and for the environment. Sorption to soil particles, volatilization, leaching, degradation (chemical, photochemical and biological oxidation), plant translocation, etc., are the principal processes that will influence on the final fate of soil contaminants in the environment. In order to interpret, evaluate the risks and make decisions about the effects of fuel compounds and assure and adequate protection of the environment, it is very important to understand the toxicology, analytics and the behaviour and fate in the environment. Within this context, the present doctoral thesis has the following objectives: Development of analytical methods for volatile compounds (MTBE, ETBE and BTEX) and diesel range organics (DRO) in soil and water. Application of those methods to the characterization of a site contaminated with hydrocarbons. Study of the dynamics of petroleum contaminants in the soil-plant-water-air system through sorption and leaching experiments and a experiment with root exudates, to study the effect of plants on contaminant mobility through soils. Characterization of gasoline and diesel phytotoxicity, with crop plants bioassays. At last, application of a phytoremediation procedure with Lupinus luteus growing on the A and B horizons of a Cambisol contaminated with diesel (1%, w/w), with the inoculation of best plant growth promoting and degrader bacteria, with the best results from previous experiment. The experiments carried out in this thesis, allowed to obtain a wide knowledge of the behaviour of those contaminants in the soil system, and to predict their final f