Table 6 Generalised properties of Utsira caprocks, based on analysis of cuttings (page 79)

Executive Summary: Carbon dioxide capture and storage (CCS) is one option for mitigating atmospheric emissions of carbon dioxide and thereby contributes in actions for stabilization of atmospheric greenhouse gas concentrations. The Bellona Foundation is striving to achieve wide implementation of carbon dioxide (CO2) capture and storage both in Norway and internationally. Bellona considers CCS as the only viable large scale option to close the gap between energy production and demand in an environmentally sound way, thereby ensuring that climate changes and acidification of the oceans due to increased CO2 concentrations in the atmosphere will be stabilised. ff

Chemical composition of a manganese nodule from the Pacific Ocean

By means of spectrographic analysis 96 samples of marine sediments were analyzed quantitatively for V, Ti, Zr, Co, Ni, Sc, Cr, and La, and semi-quantitatively for Ba and Sr. Ca has been estimated by visual comparison of spectrographic plates, and several Fe values have also been determined in the same way. Geographically 40 of these samples are from the Pacific Ocean basin, one of which is a manganese nodule, 21 from the Gulf of Mexico, 11 from Atchafalaya Bay, 8 from American Devonian to Miocene sedimentary rocks, 4 from the Mississippi Delta, 3 from the San Diego trough, 3 from off Grand Isle, 3 from Lake Pontchartrain, from Bay Rambour, 1 from Laguna Madre off the Texas coast, and 1 from the Guadalupe River, Texas. The afore-mentioned elements were sought using PdCl2 as an internal standard, after the method developed by Ahrens (1950) and his co-workers. Samples were run in duplicate, and standard deviations varied from 5 to 14 percent. Working curves, from which final values were obtained, were constructed with the use of standard granite, G1, and the standard diabase, W1, as standards. See Fairbairn and others (1951). An experiment was carried out to determine the effect of matrix change, involving CaCO3, on the spectral line intensities of the quantitatively analyzed elements. The distribution of each of the elements is discussed separately, and particular emphasis is given to oceanic "red clay", in which many elements are enriched. A general discussion is given to mineralogy of the sediments, cation exchange in its bearing on this thesis, and a brief recount of the two hypotheses of origin of oceanic "red clay". An application of the findings of this thesis to aid in the choice of the more likely hypothesis is made.

Table 1: Soil chemical properties of the analysed depth profiles in the Venice lagoon

Visual traces of iron reduction and oxidation are linked to the redox status of soils and have been used to characterise the quality of agricultural soils.We tested whether this feature could also be used to explain the spatial pattern of the natural vegetation of tidal habitats. If so, an easy assessment of the effect of rising sea level on tidal ecosystems would be possible. Our study was conducted at the salt marshes of the northern lagoon of Venice, which are strongly threatened by erosion and rising sea level and are part of the world heritage 'Venice and its lagoon'. We analysed the abundance of plant species at 255 sampling points along a land-sea gradient. In addition, we surveyed the redox morphology (presence/absence of red iron oxide mottles in the greyish topsoil horizons) of the soils and the presence of disturbances. We used indicator species analysis, correlation trees and multivariate regression trees to analyse relations between soil properties and plant species distribution. Plant species with known sensitivity to anaerobic conditions (e.g. Halimione portulacoides) were identified as indicators for oxic soils (showing iron oxide mottles within a greyish soil matrix). Plant species that tolerate a low redox potential (e.g. Spartina maritima) were identified as indicators for anoxic soils (greyish matrix without oxide mottles). Correlation trees and multivariate regression trees indicate the dominant role of the redox morphology of the soils in plant species distribution. In addition, the distance from the mainland and the presence of disturbances were identified as tree-splitting variables. The small-scale variation of oxygen availability plays a key role for the biodiversity of salt marsh ecosystems. Our results suggest that the redox morphology of salt marsh soils indicates the plant availability of oxygen. Thus, the consideration of this indicator may enable an understanding of the heterogeneity of biological processes in oxygen-limited systems and may be a sensitive and easy-to-use tool to assess human impacts on salt marsh ecosystems.

Arsenic speciation in edible alga samples by microwave-assisted extraction and high performance liquid chromatography coupled to atomic fluorescence spectrometry

Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126 μg g−1. Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography–ultraviolet photo-oxidation–hydride generation atomic–fluorescence spectrometry (HPLC–(UV)–HG–AFS) developed methods, using both anion and cation exchange chromatography. Glycerol and phosphate sugars were found in all alga samples analyzed, at concentrations between 0.11 and 22 μg g−1, whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 μg g−1). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) (<0.9 μg g−1) and generally high arsenate (As(V)) concentrations (up to 77 μg g−1) were found in most of the algae studied. The results obtained are of interest to highlight the need to perform speciation analysis and to introduce appropriate legislation to limit toxic arsenic species content in these food products.

Estudios de especiación de arsénico y acumulación de metales en muestras de interés medioambiental : Arsenic speciation and metal accumulation studies in environmental samples

Se ha estudiado la determinación de especies de arsénico y de contenidos totales de arsénico y metales pesados, específicamente cadmio, cromo, cobre, níquel, plomo y cinc, en muestras de interés medioambiental por su elevada capacidad acumuladora de metales, concretamente algas marinas comestibles y plantas terrestres procedentes de suelos contaminados por la actividad minera. La determinación de contenidos totales se ha llevado a cabo mediante espectrometría de emisión atómica con plasma de acoplamiento inductivo (ICP‐AES), así como por espectrometría de fluorescencia atómica con generación de hidruros (HG‐AFS), para bajos contenidos de arsénico. Las muestras fueron mineralizadas en medio ácido y calentamiento en horno de microondas. Los métodos fueron validados a través de su aplicación a materiales de referencia de matriz similar a la de las muestras, certificados en contenidos totales de los elementos seleccionados. Los resultados obtenidos mostraron su elevada capacidad de bioabsorción, especialmente en relación a los elevados contenidos de arsénico encontrados en algunas especies de algas pardas (Phaeophytas). En las plantas, se calcularon los factores de translocación, acumulación y biodisponibilidad de los elementos estudiados, permitiendo identificar a la especie Corrigiola telephiifolia como posible acumuladora de plomo e hiperacumuladora de arsénico. La determinación de especies de arsénico hidrosolubles en las muestras objeto de estudio, se llevó a cabo por cromatografía líquida de alta eficacia (HPLC) acoplado a ICP‐AES, HG‐ICP‐AES y HG‐AFS, incluyendo una etapa previa de foto‐oxidación. Los métodos desarrollados, mediante intercambio aniónico y catiónico, permitieron la diferenciación de hasta once especies de arsénico. Para el análisis de las muestras, fue necesaria la optimización de métodos de extracción, seleccionándose la extracción asistida por microondas (MAE) con agua desionizada. Asimismo, se realizaron estudios de estabilidad de arsénico total y de las especies hidrosolubles presentes en las algas, tanto sobre la muestra sólida como en sus extractos acuosos, evaluando las condiciones de almacenamiento adecuadas. En el caso de las plantas, la aplicación del diseño factorial de experimentos permitió optimizar el método de extracción y diferenciar entre las especies de arsénico presentes en forma de iones sencillos de mayor movilidad y el arsénico más fuertemente enlazado a componentes estructurales. Los resultados obtenidos permitieron identificar la presencia de arseniato (As(V)) y arsenito (As(III)) en las plantas, así como de ácido monometilarsónico (MMA) y óxido de trimetilarsina (TMAO) en algunas especies. En la mayoría de las algas se encontraron especies tóxicas, tanto mayoritarias (arseniato) como minoritarias (ácido dimetilarsínico (DMA)), así como hasta cuatro arsenoazúcares. Los resultados obtenidos y su estudio a través de la legislación vigente, mostraron la necesidad de desarrollar una reglamentación específica para el control de este tipo de alimentos. La determinación de especies de arsénico liposolubles en las muestras de algas se llevó a cabo mediante HPLC, en modo fase inversa, acoplado a espectrometría de masas con plasma de acoplamiento inductivo (ICP‐MS) y con ionización por electrospray (ESI‐MS), permitiendo la elucidación estructural de estos compuestos a través de la determinación de sus masas moleculares. Para ello, fue necesaria la puesta a punto de métodos extracción y purificación de los extractos. La metodología desarrollada permitió identificar hasta catorce especies de arsénico liposolubles en las algas, tres de ellas correspondientes a hidrocarburos que contienen arsénico, y once a arsenofosfolípidos, además de dos especies desconocidas. Las masas moleculares de las especies identificadas fueron confirmadas mediante cromatografía de gases acoplada a espectrometría de masas (GC‐MS) y espectrometría de masas de alta resolución (HR‐MS). ABSTRACT The determination of arsenic species and total arsenic and heavy metal contents (cadmium, chromium, cooper, nickel, lead and zinc) in environmental samples, with high metal accumulator capacity, has been studied. The samples studied were edible marine algae and terrestrial plants from soils polluted by mining activities. The determination of total element contents was performed by inductively coupled plasma atomic emission spectrometry (ICP‐AES), as well as by hydride generation atomic fluorescence spectrometry (HG‐AFS) for low arsenic contents. The samples studied were digested in an acidic medium by heating in a microwave oven. The digestion methods were validated against reference materials, with matrix similar to sample matrix and certified in total contents of the elements studied. The results showed the high biosorption capacity of the samples studied, especially regarding the high arsenic contents in some species of brown algae (Phaeophyta division). In terrestrial plants, the translocation, accumulation and bioavailability factors of the elements studied were calculated. Thus, the plant species Corrigiola telephiifolia was identified as possible lead accumulator and arsenic hyperaccumulator. The determination of water‐soluble arsenic species in the samples studied was carried out by high performance liquid chromatography (HPLC) coupled to ICP‐AES, HG‐ICP‐AES and HG‐AFS, including a prior photo‐oxidation step. The chromatographic methods developed, by anion and cation exchange, allowed us to differentiate up to eleven arsenic species. The sample analysis required the optimization of extraction methods, choosing the microwave assisted extraction (MAE) with deionized water. On the other hand, the stability of total arsenic and water‐soluble arsenic species in algae, both in the solid samples and in the water extracts, was studied, assessing the suitable storage conditions. In the case of plant samples, the application of a multivariate experimental design allowed us to optimize the extraction method and differentiate between the arsenic species present as simple ions of higher mobility and the arsenic more strongly bound to structural components. The presence of arsenite (As(III)) and arsenate (As(V)) was identified in plant samples, as well as monomethylarsonic acid (MMA) and trimethylarsine oxide (TMAO) in some cases. Regarding algae, toxic arsenic species were found in most of them, both As(V) and dimethylarsinic acid (DMA), as well as up to four arsenosugars. These results were discussed according to the current legislation, showing the need to develop specific regulations to control this kind of food products. The determination of lipid‐soluble arsenic species in alga samples was performed by reversed‐phase HPLC coupled to inductively coupled plasma and electrospray mass spectrometry (ICP‐MS and ESI‐MS), in order to establish the structure of these compounds by determining the corresponding molecular masses. For this purpose, it was necessary to develop an extraction method, as well as a clean‐up method of the extracts. The method developed permitted the identification of fourteen lipid‐soluble arsenic compounds in algae, corresponding to three arsenic‐hydrocarbons and eleven arsenosugarphospholipids, as well as two unknown compounds. Accurate mass measurements of the identified compounds were performed by gas chromatography coupled to mass spectrometry (GC‐MS) and high resolution mass spectrometry (HR‐MS).

Effects of sheep and horse manure and pine bark amendments on metal distribution and chemical properties of contaminated mine soils.

Mine soils usually contain large levels of heavy metals and poor fertility conditions which limit their reclamation and the application of phyto-remediation technologies. Two organic waste materials (pine bark compost and sheep and horse manure compost), with different pHs and varying degrees of humification and nutrient contents, were applied as amendments to assess their effects on copper (Cu) and zinc (Zn) bioavailability and on fertility conditions of mine soils. Soil samples collected from two abandoned mining areas near Madrid (Spain) were mixed with 0, 30 and 60 t ha?1 of the organic amendments. The concentrations of metals among the different mineral and organic fractions of soil were determined by several extraction procedures to study the metal distribution in the solid phase of the soil affected by the organic amendments. The results showed that the manure amendment increased the soil pH and the cation exchange capacity and enhanced the nutrient levels of these soils. The pine bark amendment decreased the soil pH and did not significantly change the nutrient status of soil. Soil pH, organic matter content and its degree of humification, which were altered by the amendments, were the main factors affecting Cu fractionation. Zn fractionation was mainly affected by soil pH. The addition of manure not only improved soil fertility, but also decreased metal bioavailability resulting in a reduction of metal toxicity. Conversely, pine bark amendment increased metal ioavailability. The use of sheep and horse manure could be a cost-effective practice for the restoration of contaminated mine soils.

Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar

The effect of biochar on the soil carbon mineral- ization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on physicochemical properties and CO2 emissions of a sandy loam soil. For this purpose, soil was amended with three different biochars (BI, BII and BIII) at a rate of 8 wt % and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coef- ficients (r 2 ) greater than 0.97. Results show a negative prim- ing effect in the soil after addition of BI and a positive prim- ing effect in the case of soil amended with BII and BIII. These results can be related to different biochar properties such as carbon content, carbon aromaticity, volatile matter, fixed carbon, easily oxidized organic carbon or metal and phenolic substance content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

Capacidad y comportamiento de la adsorción de fenol en caolines naturales y modificados

En la actualidad las industrias químicas, farmacéuticas y clínicas, originan contaminantes en aguas superficiales, aguas subterráneas y suelos de nuestro país, como es el caso del fenol, contaminante orgánico común y altamente dañino para los organismos, incluso a bajas concentraciones. Existen en el mercado diferentes metodologías para minimizar la contaminación pero muchos de estos procesos tienen un alto coste, generación de contaminantes, etc. La adsorción de contaminantes por medio de arcillas es un método ampliamente utilizado, encontrándose eficaz y económico. Pero la dificultad de adsorber un contaminante orgánico como el fenol motiva la creación de un material llamado organoarcillas. Las organoarcillas son arcillas modificadas con un surfactante, a su vez, los surfactantes son moléculas orgánicas que confieren a la superficie de la arcilla carga catiónica en lugar de aniónica, haciendo más fácil la adsorción de fenol. Para esta tesis se ha elegido el caolín como material adsorbente, fácilmente disponible y relativamente de bajo coste. Se ha trabajado con: arenas de caolín, material directo de la extracción, y caolín lavado, originado del proceso de lavado de las arenas de caolín. Ambos grupos se diferencian fundamentalmente por su contenido en cuarzo, ampliamente mayor en las arenas de caolín. Con el objetivo de desarrollar un material a partir del caolín y arenas de éste con capacidad de retención de contaminates, en concreto, fenol, se procedió a modificar los materiales de partida mediante tratamientos térmicos, mecánicos y/o químicos, dando lugar a compuestos con mayor superficie química reactiva. Para ello se sometió el caolín y las arenas caoliníferas a temperaturas de 750ºC durante 3h, a moliendas hasta alcanzar su amorfización, y/o a activaciones con HCl 6M o con NaOH 5M durante 3h a 90ºC. En total se obtuvieron 18 muestras, en las que se estudiaron las características físico-químicas, mineralógicas y morfológicas de cada una de ellas con el fin de caracterizarlas después de haber sufrido los tratamientos y/o activaciones químicas. Los cambios producidos fueron estudiados mediante pH, capacidad de intercambio catiónico (CEC), capacidad de adsorción de agua (WCU y CWC), distribución de tamaño de partícula (PSD), área de superficie específica (SBET), difracción de rayos X (XRD), espectroscopía infrarroja por transformada de Fourier (FTIR), métodos térmicos (TG, DTG y DTA), y microscopía electrónica de transmisión y barrido (SEM y TEM). Además se analizó los cambios producidos por los tratamientos en función de las pérdidas de Al y Si que acontece en las 18 muestras. Los resultados para los materiales derivados de la arenas caoliníferas fueron similares a los obtenidos para los caolines lavados, la diferencia radica en la cantidad de contenido de caolinita en los diferente grupos de muestras. Apoyándonos en las técnicas de caracterización se puede observar que los tratamientos térmico y molienda produce materiales amorfos, este cambio en la estructura inicial sumado a las activaciones ácida y alcalina dan lugar a pérdidas de Si y Al, ocasionando que sus propiedades físico-químicas, mineralógicas y morfológicas se vean alteradas. Un fuerte aumento es observado en las áreas superficiales y en la CEC en determinadas muestras, además entre los cambios producidos se encuentra la producción de diferentes zeolitas en porcentajes distintos con el tratamiento alcalino. Para la obtención de las organoarcillas, las 18 muestras se sometieron a la surfactación con hexadeciltrimetil amonio (HDTMA) 20 mM durante 24h a 60ºC, esta concentración de tensioactivo fue más alta que la CEC de cada muestra. Los camext bios anteriormente producidos por los tratamientos y activaciones, afectan de forma diferente en la adsorción de HDTMA, variando por tanto la adsorción del surfactante en la superficie de las muestras. Se determinó el tensioactivo en superficie por FTIR, además se realizó un análisis de componentes principales (PCA) para examinar la dependencia entre las relaciones Si/Al de las muestras en la capacidad de adsorción de tensioactivo, y para el estudio de la adsorción de HDTMA en las muestras se realizaron además del análisis termogravimétrico, aproximaciones con los modelos de Freundllich y Langmuir. Se persigue conocer las diferentes formas y maneras que tiene el tensioactivo de fijarse en la superficie de las muestras. En las organoarcillas resultantes se cuantificó el fenol adsorbido cuando éstas fueron puestas en contacto con diferentes concentraciones de fenol: 50, 500, 1000, 2000, y 2500 mg/l durante 24h. El contaminante sorbido se calculó por medio de cromatografía de gases, y se realizaron aproximaciones con los modelos de Freundllich y Langmuir. El comportamiento de adsorción de fenol en arcillas orgánicas es regido por las características de las muestras. De forma general se puede decir que las muestras de caolines lavados tienen más capacidad de adsorción de fenol que las muestras de arenas de caolín y que la activación alcalina ha proporcionado una mejora en la adsorción de fenol en los dos grupos. En consecuencia se han obtenido materiales adsorbentes heterogéneos y por tanto, con propiedades diferentes. Se ha evaluado el comportamiento global de las arenas de caolín por un lado y del caolín lavado por otro. Las arenas de caolín presentan altos niveles de cuarzo y su uso para ciertos tipos de industrias no son recomendados en ocasiones por el alto costo que el proceso de limpieza y purificación implicaría. Por ello es importante reseñar en este proyecto las aplicaciones que ofrecen algunas muestras de este grupo. Los ensayos acontecidos en esta tesis han dado lugar a las siguientes publicaciones: • Pérdida de Al y Si en caolines modificados térmica- o mecánicamente y activados por tratamientos químicos. A. G. San Cristóbal, C Vizcayno, R. Castelló. Macla 9, 113-114. (2008). • Acid activation of mechanically and thermally modfied kaolins. A. G. San Cristóbal, R. Castelló, M. A. Martín Luengo, C Vizcayno. Mater. Res. Bull. 44 (2009) 2103-2111. • Zeolites prepared from calcined and mechanically modified kaolins. A comparative study. A. G San Cristóbal, R. Castelló, M. A. Martín Luengo, C Vizcayno. Applied Clay Science 49 (2010) 239-246. • Study comparative of the sorption of HDTMA on natural and modified kaolin. A. G San Cristóbal, R. Castelló, J. M. Castillejo, C Vizcayno. Aceptada en Clays and Clay minerals. • Capacity of modified kaolin sand and washed kaolin to adsorb phenol. A. G San Cristóbal, R. Castelló, C Vizcayno. Envío a revista sujeto a la publicación del artículo anterior. ABSTRACT Today’s chemical, pharmaceutical and clinical industries generate pollutants that affect the soils and surface and ground waters of our country. Among these, phenol is a common organic pollutant that is extremely harmful to living organisms, even at low concentrations. Several protocols exist to minimize the effects of pollutants, but most are costly procedures or even generate other pollutants. The adsorption of hazardous materials onto clays is perhaps the most used, efficient and cost-saving method available. However, organic compounds such as phenol are difficult to adsorb and this has led to the development of materials known as organoclays, which are much better at remediating organic compounds. Organoclays are clays that have been modified using a surfactant. In turn, surfactants are organic molecules that confer a cationic rather than anionic charge to the clay surface, improving it’s capacity to adsorb phenol. For this doctorate project, kaolin was selected as an adsorbent material for the removal of phenol given its easy sourcing and relatively low cost. The materials investigated were kaolin sand, a directly extracted material, and washed kaolin, which is the byproduct of the kaolin sand washing process. The main difference between the materials is their quartz content, which is much higher in the kaolin sands. To generate a product from kaolin or kaolin sand capable of retaining organic pollutants such as phenol, both materials were subjected to several heat, chemical and/or mechanical treatments to give rise to compounds with a greater reactive surface area. To this end the two starting materials underwent heating at 750ºC for 3 h, grinding to the point of amorphization and/or activation with HCl 6M or NaOH 5M for 3 h at 90ºC. These treatments gave rise to 18 processed samples, which were characterized in terms of their morphological, mineralogical, and physical-chemical properties. The behaviour of these new materials was examined in terms of their pH, cation exchange capacity (CEC), water adsorption capacity (WCU and WCC), particle size distribution (PSD), specific surface area (SBET), and their X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermal (DTG, DTA) and scanning and transmission electron microscopy (SEM and TEM) properties. The changes conferred by the different treatments were also examined in terms of Al and Si losses. Results for the materials derived from kaolin sands and washed kaolin were similar, with differences attributable to the kaolinite contents of the samples. The treatments heat and grinding produced amorphous materials, which when subjected to acid or alkali activation gave rise to Si and Al losses. This in turn led to a change in physico- chemical, mineralogical and morphological properties. Some samples showed a highly increased surface area and CEC. Further, among the changes produced, alkali treatment led to the generation of zeolites in different proportions depending on the sample. To produce the organoclays, the 18 samples were surfacted with hexadecyltrimethylammonium (HDTMA) 20 mM for 24 h at 60ºC. This surfactant concentration is higher than the CEC of each sample. The amount of HDTMA adsorbed onto the surface of each sample determined by FTIR varied according to treatment. A principle components analysis (PCA) was performed to examine correlations between sample Si/Al ratios and surfactant adsorption capacity. In addition, to explore HDTMA adsorption by the samples, DTG and DTA data were fitted to Freundllich and Langmuir models. The mechanisms of surfactant attachment to the sample surface were also addressed. The amount of phenol adsorbed by the resultant organoclays was determined when exposed to different phenol concentrations: 50, 500, 1000, 2000, and 2500 mg/l for 24 h. The quantity of adsorbed pollutant was estimated by gas chromatography and the data fitted to the models of Freundllich and Langmuir. Results indicate that the phenol adsorption capacity of the surfacted samples is dependent on the sample’s characteristics. In general, the washed kaolin samples showed a greater phenol adsorption capacity than the kaolon sands and alkali activation improved this capacity in the two types of sample. In conclusion, the treatments used gave rise to adsorbent materials with varying properties. Kaolin sands showed high quartz levels and their use in some industries is not recommended due to the costs involved in their washing and purification. The applications suggested by the data obtained for some of the kaolin sand samples indicate the added value of this industrial by-product. The results of this research project have led to the following publications: • Pérdida de Al y Si en caolines modificados térmica- o mecánicamente y activados por tratamientos químicos. A. G. San Cristóbal, C Vizcayno, R. Castelló. Macla 9, 113-114. (2008). • Acid activation of mechanically and thermally modfied kaolins. A. G. San Cristóbal, R. Castelló, M. A. Martín Luengo, C Vizcayno. Mater. Res. Bull. 44 (2009) 2103-2111. • Zeolites prepared from calcined and mechanically modified kaolins. A comparative study. A. G. San Cristóbal, R. Castelló, M. A. Martín Luengo, C Vizcayno. Applied Clay Science 49 (2010) 239-246. • Study comparative of the sorption of HDTMA on natural and modified kaolin. A. G. San Cristóbal, R. Castelló, J. M. Castillejo, C Vizcayno Accepted in Clays and Clay minerals. • Capacity of modified kaolin sand and washed kaolin to adsorb phenol. A. G San Cristóbal, R. Castelló, C Vizcayno. Shipment postponed, subject to the publication of the previous article.

Guidelines of natural zeolites characterization for acid mine drainage treatment. Case study Guayaquil, Ecuador

Zeolites constitute one of the less common groups of tectosilicates. Zeoli1es with pores between -2 to 10 A in their structures have strong sorption capacity and are widely used in industrial and municipal operations to eliminate toxic substances. One of the major environmental problems in the mining activity is the treating of acid mine drainage. In this context, it is very important to search alternatives to manage this challenge. One feasible alternative is using zeolitic tuffs. The results of the physical-chemical characterization of zeolitic tuffs are the c1ue lo continue or not with deeper analysis and tests 01 acid mine drainage treatments. The guidelines to reach this purpose are the main goal of this work. Zeolite 1uff samples (named as XB_01 and XB_02) studied in this work were laken rn the Late Cretaceous Coastal Cayo Arch Ecuador, specifically in the Guaraguao River, showing the most important characteristics of heulandite zeolitic tuffs. X-ray powder diffraction (XRD) tests were developed in order to confirm that the samples belong to the heulandite-type zeoli1ic tuffs. Additionally, Thermogravimetric analysis (TG), Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and X-ray fluorescence (XRF) of the samples was necessary in order to define the Si/Al ratio and the main mineralogical phases. The XB_01 sample shows a higher ratio Si/Al than XB_02 sample. The cation exchange capacity est was the fundamental step to define the potentiality of the zeolite to use in acid mine drainage treatment Three methodologies were employed to determine the cation exchange capacity. The Cuban standard 626 and the ammonium exchange methodologies reflect results more consistent with each other. This is the starting point to continue with deeper studies such as breakthrough curves for heavy metal ions found in acid mine waters.

Gβ5 prevents the RGS7-Gαo interaction through binding to a distinct Gγ-like domain found in RGS7 and other RGS proteins

The G protein β subunit Gβ5 deviates significantly from the other four members of Gβ-subunit family in amino acid sequence and subcellular localization. To detect the protein targets of Gβ5 in vivo, we have isolated a native Gβ5 protein complex from the retinal cytosolic fraction and identified the protein tightly associated with Gβ5 as the regulator of G protein signaling (RGS) protein, RGS7. Here we show that complexes of Gβ5 with RGS proteins can be formed in vitro from the recombinant proteins. The reconstituted Gβ5-RGS dimers are similar to the native retinal complex in their behavior on gel-filtration and cation-exchange chromatographies and can be immunoprecipitated with either anti-Gβ5 or anti-RGS7 antibodies. The specific Gβ5-RGS7 interaction is determined by a distinct domain in RGS that has a striking homology to Gγ subunits. Deletion of this domain prevents the RGS7-Gβ5 binding, although the interaction with Gα is retained. Substitution of the Gγ-like domain of RGS7 with a portion of Gγ1 changes its binding specificity from Gβ5 to Gβ1. The interaction of Gβ5 with RGS7 blocked the binding of RGS7 to the Gα subunit Gαo, indicating that Gβ5 is a specific RGS inhibitor.

Characterization of Two Novel Type I Ribosome-Inactivating Proteins from the Storage Roots of the Andean Crop Mirabilis expansa1

Two novel type I ribosome-inactivating proteins (RIPs) were found in the storage roots of Mirabilis expansa, an underutilized Andean root crop. The two RIPs, named ME1 and ME2, were purified to homogeneity by ammonium sulfate precipitation, cation-exchange perfusion chromatography, and C4 reverse-phase chromatography. The two proteins were found to be similar in size (27 and 27.5 kD) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their isoelectric points were determined to be greater than pH 10.0. Amino acid N-terminal sequencing revealed that both ME1 and ME2 had conserved residues characteristic of RIPs. Amino acid composition and western-blot analysis further suggested a structural similarity between ME1 and ME2. ME2 showed high similarity to the Mirabilis jalapa antiviral protein, a type I RIP. Depurination of yeast 26S rRNA by ME1 and ME2 demonstrated their ribosome-inactivating activity. Because these two proteins were isolated from roots, their antimicrobial activity was tested against root-rot microorganisms, among others. ME1 and ME2 were active against several fungi, including Pythium irregulare, Fusarium oxysporum solani, Alternaria solani, Trichoderma reesei, and Trichoderma harzianum, and an additive antifungal effect of ME1 and ME2 was observed. Antibacterial activity of both ME1 and ME2 was observed against Pseudomonas syringae, Agrobacterium tumefaciens, Agrobacterium radiobacter, and others.

La roca magica: Uses of natural zeolites in agriculture and industry

For nearly 200 years since their discovery in 1756, geologists considered the zeolite minerals to occur as fairly large crystals in the vugs and cavities of basalts and other traprock formations. Here, they were prized by mineral collectors, but their small abundance and polymineralic nature defied commercial exploitation. As the synthetic zeolite (molecular sieve) business began to take hold in the late 1950s, huge beds of zeolite-rich sediments, formed by the alteration of volcanic ash (glass) in lake and marine waters, were discovered in the western United States and elsewhere in the world. These beds were found to contain as much as 95% of a single zeolite; they were generally flat-lying and easily mined by surface methods. The properties of these low-cost natural materials mimicked those of many of their synthetic counterparts, and considerable effort has made since that time to develop applications for them based on their unique adsorption, cation-exchange, dehydration–rehydration, and catalytic properties. Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units. From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future.

Manganese oxide minerals: Crystal structures and economic and environmental significance

Manganese oxide minerals have been used for thousands of years—by the ancients for pigments and to clarify glass, and today as ores of Mn metal, catalysts, and battery material. More than 30 Mn oxide minerals occur in a wide variety of geological settings. They are major components of Mn nodules that pave huge areas of the ocean floor and bottoms of many fresh-water lakes. Mn oxide minerals are ubiquitous in soils and sediments and participate in a variety of chemical reactions that affect groundwater and bulk soil composition. Their typical occurrence as fine-grained mixtures makes it difficult to study their atomic structures and crystal chemistries. In recent years, however, investigations using transmission electron microscopy and powder x-ray and neutron diffraction methods have provided important new insights into the structures and properties of these materials. The crystal structures for todorokite and birnessite, two of the more common Mn oxide minerals in terrestrial deposits and ocean nodules, were determined by using powder x-ray diffraction data and the Rietveld refinement method. Because of the large tunnels in todorokite and related structures there is considerable interest in the use of these materials and synthetic analogues as catalysts and cation exchange agents. Birnessite-group minerals have layer structures and readily undergo oxidation reduction and cation-exchange reactions and play a major role in controlling groundwater chemistry.

Detection of Ca2+-Dependent Transglutaminase Activity in Root and Leaf Tissue of Monocotyledonous and Dicotyledonous Plants

Protein extracted from root and leaf tissue of the dicotyledonous plants pea (Pisum sativum) and broad bean (Vicia faba) and the monocotyledonous plants wheat (Triticum aestivum) and barley (Hordeum vulgare) were shown to catalyze the incorporation of biotin-labeled cadaverine into microtiter-plate-bound N′,N′-dimethylcasein and the cross-linking of biotin-labeled casein to microtiter-plate-bound casein in a Ca2+-dependent manner. The cross-linking of biotinylated casein and the incorporation of biotin-labeled cadaverine into N′,N′-dimethylcasein were time-dependent reactions with a pH optimum of 7.9. Transglutaminase activity was shown to increase over a 2-week growth period in both the roots and leaves of pea. The product of transglutaminase's protein-cross-linking activity, ε-(γ-glutamyl)-lysine isodipeptide, was detected in root and shoot protein from pea, broad bean, wheat, and barley by cation-exchange chromatography. The presence of the isodipeptide was confirmed by reversed-phase chromatography. Hydrolysis of the isodipeptide after cation-exchange chromatography confirmed the presence of glutamate and lysine.