The molecular-level speciation of arsenic has been determined in a soil profile in the Massif Central near Auzon, France that was impacted by As-based pesticides by combining conventional techniques (XRD, selective chemical extractions) with X-ray absorption spectroscopy (XAS). The arsenic concentration is very high at the top (>7000 mg kg(-1)) and decreases rapidly downward to a few hundreds of milligrams per kilogram. A thin layer of schultenite (PbHAsO4), a lead arsenate commonly used as an insecticide until the middle of the 20th century, was found at 10 cm depth. Despite the occurrence of this As-bearing mineral, oxalate extraction indicated that more than 65% of the arsenic was released upon dissolution of amorphous iron oxides, suggesting a major association of arsenic with these phases within the soil profile. Since oxalate extraction cannot unambiguously distinguish among the various chemical forms of arsenic, these results were confirmed by a direct in situ determination of arsenic speciation using XAS analysis. XANES data indicate that arsenic occurs mainly as As(V) along the soil profile except for the topsoil sample where a minor amount (7%) of As(III) was detected. EXAFS spectra of soil samples were fit by linear combinations of model compounds spectra and by a shell-by-shell method. These procedures clearly confirmed that As(V) is mainly (at least 80 wt %) associated with amorphous Fe(III) oxides as coprecipitates within the soil profile. If any, the proportion of schultenite, which was evidenced by XRD in a separate thin white layer, does not account for more than 10 wt % of arsenic in soil samples. This study emphasizes the importance of iron oxides in restricting arsenic dispersal within soils following dissolution of primary As-bearing solids manufactured for use as pesticides and released into the soils.

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Other critical problems, that impact on infrastructure and industry are climate change, global warming and greenhouse emissions, all interrelated phenomena.This chapter presents important aspects of corrosion in industrial infrastructure, its causes, impacts, control, protection and prevention methods. Materials in industryMetallic materials play a key role in the development of a country and its sustained growth in the context of the global economy. Table 1 shows a classification and the properties of dif-

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La creciente actividad industrial de extracción del aceite de palma africana (Elaeis guineensis Jacq.) en el Ecuador ha provocado la generación de elevados volúmenes de residuos de raquis, los cuales actualmente son dispuestos a cielo abierto en las plantaciones de este vegetal. Por tal motivo, el objetivo de la propuesta doctoral es obtener materiales compuestos a partir de matrices termoplásticas y desechos lignocelulósicos derivados de la producción industrial de aceite de palma africana en Ecuador. Como etapa inicial se ha realizado la recolección y molienda de los desechos de fibra. Una vez determinado el comportamiento granulométrico de la fibra molida se procedió a la caracterización de la composición fisicoquímica y al análisis por espectrometría infrarroja con transformadas de Fourier. Los resultados muestran comportamiento granulométrico independiente de la ubicación de la fibra en el raquis y mayor porcentaje de retenido a una abertura de malla de 0,42 mm. La espectrofotometría infrarroja evidencia la presencia de bandas características de la celulosa, hemicelulosa y lignina de similar intensidad en cualquier fracción peduncular del residuo.

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