Modelling titration curves of mixed materials with variable and permanent surface charge: application

3 pages, 1 figure, 2 references. Congreso celebrado del 7-10, septiembre, 1987, Sevilla, España. EUROCLAY'87.Two well-known materials, lepidocrocite (specilic sur-face area 115 m2g-1) and montmorillonite (internal surface are a 700 m2g-1), can be useful to test the mathematical model described in the preceding communication. With thispurpose, acid and base titration curves of both minerals and of mixtures containing 80% (w/w) of lepidocrocite (sample LM) and 80% montmorillonite (sample ML) were obtained at three ionic strengths (0.01, 0.1 and 1 M NaCl). The amounts of titrant consumed by the suspensions at each pH were corrected for the amount consumed by the corresponding solution at the same pH. The resulting graphs are shown in next page. Dashed lines will be explained later.Peer reviewe

Influence of inorganic amendments on trace metal extractable contents in urban soils

2 páginas, 1 tabla y 2 referencias. Poster contributions- SO-62 presentado en el VIII International symposium on analytical methodology in the environmental field. XIII Reunión de la Sociedad española de química analítica, VIII ISAMEF/SEQA 2003. University of A Coruña October 21-24, 2003.Urban soils in medium size and big cities, have shown in many cases (Madrid et al. 2002) high contents of some trace metals, for example lead, copper, or zinc, due to traffic, industry, etc (Bullock and Gregory, 1991). The presence of these metals at high concentrations in the soils of green areas, mainly recreational areas, is a potential source of dangerous elements for human health. For that reason, the availability of these contaminant elements is an essential control parameter, because it is related to plant uptake, and to their transfer to humans via suspended dust or by direct contact, specially by small childrens. The addition of amendments to the soil is a reasonable technique to reduce the availability of trace metals. The relationship between trace metals and different inorganic amendments was studiedXunta de Galicia: Consellería de Medio Ambiente. Dirección Xeral do Centro de Desenvolvemento Sostible. Xunta de Galicia: Consellería de Innovación, de Industria e Comercio. Dirección Xeral de Investigación e Desenvolvemento. Xunta de Galicia: Consellería de Educación e Ordenación Universitaria. Dirección Xeral de Universidades. Ministerio de Ciencia y Tecnología. Dirección General de Investigación. Excma. Diputación Provincial de A Coruña. Excmo. Ayuntamiento de A Coruña REPSOL, YPF, ENDESA GENERACIÓN, SIR, ENCE, GAIRESA, UNIÓN FENOSA, TIRME.Peer reviewe

Fractionation of potentially toxic elements in urban soils from five European cities by means of a harmonised sequential extraction procedure

The revised (four-step) BCR sequential extraction procedure has been applied to fractionate the chromium, copper, iron, manganese, nickel, lead and zinc contents in urban soil samples from public-access areas in five European cities. A preliminary inter-laboratory comparison was conducted and showed that data obtained by different laboratories participating in the study were sufficiently harmonious for comparisons to be made between cities and land types (e.g. parks, roadside, riverbanks, etc.). Analyte recoveries by sequential extraction, with respect to direct aqua regia digestion, were generally acceptable (100 ± 15%). Iron, nickel and, at most sites, chromium were found mainly in association with the residual phase of the soil matrix. Copper was present in the reducible, oxidisable and residual fractions, whilst zinc was found in all four sequential extracts. Manganese was strongly associated with reducible material as, in some cities, was lead. This is of concern because high lead concentrations were present in some soils (>500 mg kg−1) and the potential exists for remobilisation under reducing conditions. As would be expected, extractable metal contents were generally highest in older, more heavily industrialised cities. Copper, lead and zinc showed marked (and often correlated) variations in concentrations between sites within the same city whereas manganese and, especially, iron, did not. No overall relationships were, however, found between analyte concentrations and land use, nor between analyte partitioning and land use

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Influence of traffic distribution on some metal contents in urban soils: "urban" and "natural" elements

In contrast with soils in agricultural areas, soils in urban areas (particularly in parks and gardens) have a direct infl uence on public health not related with production of food. This is due to the fact that it can come easily in contact with humans and be transferred to them, either as suspended dust or by direct contact. Moreover, even though they are rarely used for agronomic activities, they receive higher than normal loads of contaminants from traffi c and, in heavily industrialised cities, industrial activity.Peer reviewe

Elementos traza y nutrientes en suelos y herbáceas de parques y zonas verdes de Sevilla.

The use of urban soils, unlike the traditional agricultural use of soils in rural areas, is in most cases of a recreational and ornamental character. For that reason it is often forgotten or disregarded that urban soils have a direct influence on public health. Such urban soils receive significant inputs of pollutants from human activities, and they can enter organisms as airborne dust, by direct contact or even by ingestion. It is thus necessary to know the quality of urban soils, especially concerning pollutant concentration and availability. Urban soils of Sevilla were sampled in 154 sites, 85 of them covered by grasses. Soils were characterised and their contents in potentially toxic metals (PTM) were measured, both by aqua regia digestion (pseudo totals) and by extraction with 0.05 M EDTA (available fraction). The concentrations of PTM in the grasses were also determined. Most soils were found to be neutral, rich in lime, low organic matter contents and particle size distributions within the various loam classes. An incipient or moderate pollution in Cu, Pb and Zn is observed, particularly within the historic quarters, as well as low contents of other PTM. Concentrations of PTM in the grasses are quite comparable to those commonly found in non-polluted areas. The relationship between metal grass contents and soil concentrations is highly significant only in the case of Cd or Zn, but not for the other metals. Multivariate analysis shows that no relation exists between metals in soils and in plants in any case, but a strong association exists among the soil concentrations of Ba, Cu, Pb and Zn and that of organic matter. It is concluded that urban soils of Sevilla show an incipient to moderate pollution with PTM in some sites, particularly in areas close to the historic centre, where a periodic monitoring is recommended. Application of some non-toxic material with metal-immobilising power might be convenient to reduce metal availability.La función de los suelos urbanos frecuentemente no es la tradicional de suelos agrícolas, ya que sobre todo es estética y recreativa, por lo que suele olvidarse que estos suelos tienen una influencia directa sobre la salud de los ciudadanos, considerándose poco significativa. Sin embargo, estos suelos reciben aportaciones muy significativas de contaminantes procedentes de diversas actividades humanas, y pueden introducirse en el organismo como polvo en suspensión, por contacto directo e incluso por ingestión. Es pues necesario conocer la calidad de los suelos urbanos, especialmente el contenido y disponibilidad de contaminantes. Se escogieron 154 suelos urbanos de Sevilla, 85 de ellos cubiertos por herbáceas. Los suelos se caracterizaron y se midieron sus contenidos en metales potencialmente tóxicos (MPT) por digestión con agua regia (pseudo totales) y extracción con EDTA 0,05 M (fracción disponible). Igualmente se midieron los mismos metales en las herbáceas. La mayoría de las muestras son neutras, calizas, con materia orgánica baja y distribuciones de tamaños de partículas equilibradas. Se observa una contaminación incipiente en Cu, Pb y Zn, especialmente en el casco antiguo, y contenidos bajos de otros MPT. Los contenidos en las herbáceas son comparables a los considerados normales. La relación entre el Cd y el Zn de las plantas y de los suelos (totales o disponibles) es muy significativa, aunque no para otros metales. El análisis multivariante confirma que no existe relación entre los metales en los suelos y las plantas. Sí existe fuerte asociación entre el Cu, Pb y Zn de los suelos y la materia orgánica. La contaminación con metales en suelos de Sevilla puede considerarse como moderada o incipiente, pero conviene realizar un seguimiento en algunos puntos, en especial en jardines cercanos al casco antiguo. En tales casos se recomienda enmendar los suelos de estos puntos con sustancias inocuas inmovilizadoras de metales.Comisión Europea y la Dirección General de Investigación del Ministerio de Educación y Ciencia por la ayuda económica a los proyectos de investigación EVK4-CT-2001-00053 y CTM2005-02256, respectivamente.Peer reviewe

Metales potencialmente tóxicos en suelos urbanos de Sevilla: relaciones entre los contenidos en suelos y en herbáceas, y distribución espacial.

9 páginas, 4 tablas, 25 referencias.-- Aparece publicado en el Capítulo 2: contaminación y recuperación de suelos.-- Trabajo presentado con motivo del II congreso Ibérico de la Ciencia del Suelo que tuvo lugar en Huelva (España) del 13-17, junio, 2006, como parte de la actividad científica de la Sociedad Española de la Ciencia del Suelo (SPCS) y la Sociedade Portuguesa da Ciência do Solo (SPCS).[EN] The function of urban soils is often different from the traditional use in agricultural areas, and is often of an ornamental and recreational character. For that reason is often forgotten or disregarded as non-significant that urban soil has a direct influence on human health. However, urban soils receive significant inputs of pollutants from human activities, which can enter organisms as airborne dust, by direct contact and even through ingestion. Therefore it is necessary to check urban soil quality concerning the contents of pollutants and their availability. Urban soils of Sevilla were sampled in 154 sites, 85 of which were covered by grasses. Soils were characterized and analysed for their contents of potentially toxic metals (PTM), both by aqua regia digestion (pseudo-totals) and by extraction with 0.05 M EDTA (available fraction). Grass samples were also analysed for PTM contents.[ES] La mayoría de los suelos en áreas urbanas cumplen funciones diferentes de la tradicional en zonas rurales como medio de producción de alimentos. Son evidentes en suelos urbanos su función estética y recreativa en parques y jardines públicos y su contribución a preservar la biodiversidad. Por otra parte, en áreas urbanas el suelo tiene una influencia directa sobre la salud de los ciudadanos frecuentemente olvidada o considerada como poco significativa. Esta tendencia a minimizar la importancia de los suelos urbanos en la salud humana es, en parte, la causa de que sólo algunos países incluyan en sus normativas medioambientales límites máximos específicos en los contenidos de metales potencialmente tóxicos (MPT) para suelos de áreas residenciales y de esparcimiento, y en la mayoría de los países se establecen valores umbral o indicativos para suelos en general, sin especificar uso. Sin embargo, los suelos urbanos están expuestos a aportaciones muy significativas de contaminantes diversos procedentes del tráfico, actividades industriales, desechos, etc., y su substrato está frecuentemente mezclado con materiales antropogénicos que modifican sus propiedades (Bullock y Gregory, 1991).La celebración del II Congreso Ibérico de la Ciencia del Suelo ha sido cofinanciada por el Ministerio de Educación y Ciencia y la Unión Europea (Fondos FEDER) por medio de la Acción Complementaria CTM2006-26230-E.Peer reviewe

Efecto de la adición de algunos minerales sobre la disponibilidad de metales pesados en suelos

4 páginas, 2 tablas, 5 referencias.-- Publicado en el Capítulo IV: Contaminación y Medio Ambiente.-- Trabajo presentado a la XVII Reunión Científica de la Sociedad Española de Arcillas, celebrada en Elche (Alicante) y Castellón, del 27-29 de noviembre de 2002.La adición a los suelos de diversos materiales capaces de "fijar" metales a través de diferentes reacciones químicas es uno de los métodos más aceptados para corregir situaciones de contaminación de suelos con metales pesados (Brown, 1997; Mench et al., 1998). Enmiendas orgánicas que forman complejos muy estables con los iones metálicos; sustancias capaces de elevar el pH del medio favoreciendo la insolubilización de metales en forma de hidróxidos o carbonatos; óxidos poco solubles capaces de adsorber específicamente diversos iones; o minerales que retienen cationes por intercambio iónico, son algunos de los ejemplos más estudiados a este respecto. En la mayoría de los casos es de esperar que actúen en el sentido de disminuir la disponibilidad de los metales presentes en el suelo. Sin embargo, el comportamiento de un mineral que se considere a priori un potencial "fijador" de metales debe estudiarse con detalle antes de su uso con este propósito, ya que es probable que su eficacia dependa del tipo de suelo, del metal que se pretende fijar, y de las características particulares del mineral elegido. En este trabajo se ha estudiado la acción de tres materiales, una zeolita en forma ácida, un óxido de hierro y un óxido de manganeso, al mezclarse con suelos de varios orígenes con contenidos relativamente altos en diversos metales, sobre la fracción de dichos metales soluble en varios extractantes. La extracción con solución de EDT A es una forma ampliamente admitida de simular la disponibilidad de metales en suelos, y la cantidad disuelta por digestión en aqua regia (algunas veces llamada "quasi total") es a su vez una estimación del contenido en metales con significación medioambiental. Se excluyen así las formas muy fuertemente inmovilizadas en estructuras cristalinas particularmente estables.Peer reviewe

Charge properties of mixtures of minerals with variable and constant surface-charge

Surface charge of mixtures of lepidocrocite and illite determined by adsorption of potential-determining and electrolyte ions is studied as a function of pH and NaCl concentration. Deviations between results obtained by both methods were a function of the illite content of the mixtures, and can be mainly attributed to coatings of hydroxyaluminium complexes on the constant charge surfaces of the clay mineral, which can react with H+ ions or release exchange sites by precipitation of well-formed hydroxides. These coatings of aluminium complexes can cause H+ consumptions similar to those due to lepidocrocite.Peer Reviewe

Use of C-18 reverse-phase cartridges for estimation of metal complexation by a residue from olive oil industry

Formation of complexes between Cu and organic polymers present in olive mill wastewater (OMW) is shown to be a cause of metal solubilization by the residue, using C-18 reverse-phase cartridges (RPC) for separating the complexed metal. Nearly 100% of the metal released from a polluted river sediment by OMW solutions is retained by the cartridges. The proportion of Cu retained by the cartridges is somewhat lower (50-80%), if the OMW solution initially contains Cu. About 70-80% of Cu released by OMW from a soil column previously loaded with high doses of metal is also retained by the cartridges. Incomplete Cu retentions are not thought to be due to a lack of efficiency of RPC in immobilizing Cu complexes, but to the formation of an equilibrium between free and complexed forms of the metal.The Dirección General de Investigación Científica y Técnica (Spain), part of Project no. PB92-0052.Peer Reviewe