Ability of Cytisus scoparius for phytoremediation of soils from a Pb/Zn mine: Assessment of metal bioavailability and bioaccumulation.

Abandoned mining areas are an environmental concern for aquatic and terrestrial ecosystems due to their unfavourable soil properties and high levels of potentially toxic elements. Despite this, some plant species may grow spontaneously and colonise these areas; being suitable in many cases for restoration practices, since they may accumulate metals in their tissues. This study aims to assess the effectiveness of 14 chemical soil extractants to predict the bioavailability of toxic elements (Cd, Pb and Zn) in soils from the abandoned Pb/Zn mine of Rubiais (NW Spain), based on root and shoot metal contents in Cytisus scoparius (L.) Link, which grows spontaneously in this area. Afterwards, its potential for phytoremediation activities was assessed. Mine soils showed high contents Cd (1.77-14.38 mg kg-1), Pb (850-2137 mg kg-1) and Zn (1754-12090 mg kg-1). Cytisus scoparius grows in spite of these high metal contents; accumulating Zn and Pb in its roots, Zn in the aerial part and excluding mostly Cd from its tissues. None of the extractants used to determine the bioavailable content of Pb allow predicting its availability for C. scoparius. However, LMWOA was the most effective extractant to determine the bioavailability of Cd and Zn for this species. Besides, NH4NO3 and Ca(NO3)2 are also good indicators for Zn bioavailability. The analysis of bioconcentration and translocation factors suggest that C. scoparius behaves like a Zn accumulator plant, whereas alternatively, it behaves like a Pb phytostabiliser and as a Cd excluder species. Thus, C. scoparius can be used as a species for mine soil restoration, decreasing the mobility of metals and preventing their dispersion to another ecosystem compartments.

Cistus monspeliensis L. as a potential species for rehabilitation of soils with multielemental contamination under Mediterranean conditions.

The Iberian Pyrite Belt (IPB; SW of the Iberian Peninsula) is one of the most important volcanogenic massive sulphide ore deposits in the world. Cistus monspeliensis L. is a native woody shrub that grows spontaneously in non-contaminated soils as well as in soils with multielemental contamination from the IPB. In this study, different ecophysiological parameters of C. monspeliensis growing in soils with different levels of metal(loid)s were evaluated to assess the potential of this species for revegetation of degraded areas. Composite samples of plants and rhizosphere soils were sampled in São Domingos and Lousal mines and in a reference area without soil contamination (Pomarão, Portugal) (Portuguese sector of IPB). Classical characterisation of the soils and quantification of their total and available metal(loid) concentrations were done. Multielemental concentration was determined in plants (shoots and roots). Ecophysiological parameters were also determined in shoots: concentrations of pigments (chlorophylls, anthocyanins and carotenoids), antioxidants (glutathione and ascorbate) and hydrogen peroxide as well as activities of several antioxidative enzymes. Although mining soils present high total concentrations of potentially hazardous elements, their available fractions were low and similar among studied areas. Soil pH as well as concentrations of extractable P, total concentrations of As, Cd and Ni and concentrations of Cu, Cr, Ni, Pb and Sb in the soil available fraction differentiate the studied areas. Only concentrations of Cd, Pb and Sb in roots and shoots were explained by the concentrations of the same elements in the soil available fraction. Although the majority of elements were translocated from roots to shoots, the shoots concentrations were below the toxic values for domestic animals and only As, Mn and Zn reached phytotoxic concentrations. Ecophysiological parameters were similar independently of the studied area. Due to its adaptability, tolerance and standard plant features, C. monspeliensis is a good choice for rehabilitation of soils with multielemental contamination under similar climatic characteristics.

Pb pollution in soils from a trap shooting range and the phytoremediation ability of Agrostis capillaris L.

Pb pollution caused by shooting sport activities is a serious environmental problem that has increased considerably in recent decades. The aims of this study were firstly to analyze Pb pollution in soils from a trap shooting range abandoned in 1999, secondly to study the effectiveness of different extractants [CaCl2, DTPA, NH4OAc, low molecular weight organic acids (LMWOA), and bidistilled water (BDW)] in order to determine Pb bioavailability in these soils, and finally to evaluate the phytoremediation ability of spontaneous vegetation (Agrostis capillaris L.). To this end, 13 soils from an old trap shooting range (Galicia, NW Spain) were studied. It was found that Pb levels in the soils were higher than 100 mg kg(-1), exceeding the generic reference levels, and three of these samples even exceeded the USEPA threshold level (400 mg kg(-1)). In general, the reagent that best represents Pb bioavailability and has the greatest extraction efficiency was CaCl2, followed by DTPA, NH4OAc, LMWOA, and BDW. A. capillaris Pb contents ranged between 9.82 and 1107.42 mg kg(-1) (root) and between 6.43 and 135.23 mg kg(-1) (shoot). Pb accumulation in roots, as well as the presence of secondary mineral phases of metallic Pb in the adjacent soil, showed the phytostabilization properties of A. capillaris.

Validation of TOF-SIMS and FE-SEM/EDS Techniques Combined with Sorption and Desorption Experiments to Check Competitive and Individual Pb2+ and Cd2+ Association with Components of B Soil Horizons.

Sorption and desorption experiments were performed by the batch method on the B horizons of five natural soils: Umbric Cambisol, Endoleptic Luvisol, Mollic Umbrisol, Dystric Umbrisol, and Dystric Fluvisol. Individual and competitive sorption and desorption capacity and hysteresis were determined. The results showed that Pb2+ was sorbed and retained in a greater quantity than Cd2+ and that the hysteresis of the first was greater than that of the second. The most influential characteristics of the sorption and retention of Pb2+ were pH, ECEC, Fe and Mn oxides and clay contents. For Cd2+ they were mainly pH and, to a lesser extent, Mn oxides and clay content. The combined use of TOF-SIMS, FE-SEM/EDS and sorption and desorption analyses was suitable for achieving a better understanding of the interaction between soil components and the two heavy metals. They show the preferential association of Pb2+ with vermiculite, chlorite, Fe and Mn oxides, and of Cd2+ with the same components, although to a much lesser extent and intensity. This was due to the latter's higher mobility as it competed unfavourably with the Pb2+ sorption sites. TOF-SIMS and FE-SEM/EDS techniques confirmed the results of the sorption experiments, and also provided valuable information on whether the soil components (individually or in association) retain Cd2+ and/or Pb2+; this could help to propose effective measures for the remediation of contaminated soils.

Competitive sorption and desorption of trace elements by Tunisian Aridisols Calcorthids.

The sorption and retention processes play an important role in determining the bioavaibility and fate of trace elements in soils. Sorption and desorption of Pb(2+), Zn(2+), Ni(2+), Cu(2+), and Co(2+) in three Tunisian Aridisols Calcorthids (AR1, AR2, and AR3) were studied using batch experiments. Sorption and retention capacities were determined by means of K r parameter and they were related to soil properties. The results showed that in all studied soils, K r values for Pb(2+) and Cu(2+) were higher than those of Zn(2+), Ni(2+), and Co(2+) indicating that soils have higher affinity for the first ones. The high sorption and retention capacity of the three studied soils is ascribed to their alkaline pH and their high carbonates contents favoring the precipitation of these elements. Moreover, bivariate correlation analysis showed that sorption and retention of the studied cations was also strongly correlated with clay fraction and Fe oxides contents. All soils show high sorption irreversibility of Pb(2+), Zn(2+), Ni(2+), Cu(2+), and Co(2+). The soils with highest sorption capacity show also the highest irreversibility.

Identifying sources of Pb pollution in urban soils by means of MC-ICP-MS and TOF-SIMS.

Lead pollution was evaluated in 17 urban soils from parks and gardens in the city of Vigo (NW Spain). The Pb isotope ratios ((207)Pb/(206)Pb, (208)Pb/(204)Pb, (206)Pb/(204)Pb and (208)Pb/(206)Pb) were determined after being measured by MC-ICP-MS. The association of the isotopes ((204)Pb, (206)Pb, (207)Pb and (208)Pb) with the different components of the soil was studied using TOF-SIMS. The isotopic ranges obtained for the samples were between 1.116 and 1.203 ((206)Pb/(207)Pb), 2.044-2.143 ((208)Pb/(206)Pb), 37.206-38.608 ((208)Pb/(204)Pb), 15.5482-15.6569 ((207)Pb/(204)Pb) and 17.357-18.826 ((206)Pb/(204)Pb). The application of the three-end-member model indicates that the Pb derived from petrol is the main source of Pb in the soils (43.51% on average), followed by natural or geogenic Pb (39.12%) and industrial emissions (17.37%). The emissions derived from coal combustion do not appear to influence the content of Pb in the soil. TOF-SIMS images show that the Pb mainly interacts with organic matter. This technique contributes to the understanding of the association of anthropogenic Pb with the components of the soil, as well as the particle size of these associations, thus allowing the possible sources of Pb to be identified.

Copper distribution in surface and subsurface soil horizons.

The horizons of four natural soils were treated with Cu(2+) in an acid medium to study the retention capacity of Cu. The possible mineralogical changes arising because of the treatment were also studied. The soil properties and characteristics with the greatest influence on the metal retention and its distribution among the different soil fractions were determined. Crystalline phases of each horizon were determined by X-ray diffraction (XDR). The morphology, structural distribution and particle chemical composition of soil samples were investigated using field emission scanning electron microscopy. Cu distribution in the different geochemical phases of the soil was studied using a sequential extraction. The treatment led to an increase in the amorphous phases and the formation of new crystalline phases, such as rouaite (Cu2(NO3)(OH)3) and nitratine (NaNO3). Cu was also found superficially sorbed on amorphous hydroxy compounds of Fe that interact with albite, muscovite and gibbsite, and also on spherical and curved particles of aluminium clays. The largest amount of Cu retained was in an exchangeable form, and the smallest amount associated with the crystalline Fe oxides and residual fraction. In the surface horizons, the predominant Cu retention process is complexation in organomineral associations, while in the subsurface horizons it is adsorption.

Enrichment of marsh soils with heavy metals by effect of anthropic pollution.

The impact of waste disposal on marsh soils was assessed in topsoil samples collected at eight randomly selected points in the salt marsh in Ramallosa (Pontevedra, Spain) at 4-month intervals for 2 years. Polluted soil samples were characterized in physico-chemical terms and their heavy metal contents determined by comparison with control, unpolluted samples. The results revealed a marked effect of waste discharges on the soils in the area, which have low contents in heavy metals under normal environmental conditions. In fact, the studied soils were found to contain substantial amounts of total and DTPA-extractable Cd, Cu, Pb and Zn. Based on the relationship of the redox potential with the DTPA-extractable Cd, Cu, Pb, and Zn contents of the soils, strongly reductive conditions raised the total contents in these elements by effect of their remaining in the soils as precipitated sulphides. Such contents, however, decreased as oxidative conditions gradually prevailed. The contents in DTPA-extractable metals increased with increasing Eh through the release of the metals in ionic form to the soil solution under oxidative conditions. The contents in heavy metals concentrating in the polluted soils were several times higher than those in the control soils (viz. 2 vs. 6 for Cd, 4 vs. 6 for Cu, 4 vs. 20 for Pb, and 2 vs. 15 for Zn, all in mgkg(-1)). This can be expected to influence the amounts of available heavy metals present in the soils, and hence the environmental quality of the area, in the near future. Based on its geoaccumulation index (Class >/=3 for Cd and Cu, and 1-4 for Pb and Zn), the Ramallosa marsh is highly polluted with Cd and moderately to highly polluted with Cu, Pb and Zn. The enrichment factors obtained confirm that the salt marsh is highly polluted (especially with Cd) as the primary result of anthropic activity.

Degradation of fuel oil in salt marsh soils affected by the Prestige oil spill.

We assessed natural degradation of fuel oil in three marshes from Galicia (Spain) affected by the Prestige oil spill (Baldaio, Barizo, and Muxía). Soil samples collected from polluted and unpolluted areas on four different dates were used to determine total petroleum hydrocarbon content and fuel-oil components. Natural degradation was monitored by analysing changes in the proportion of saturated hydrocarbons, aromatics, asphaltenes and resins in the soils, and also by evaluating the degree of depletion of saturated hydrocarbons on each sampling date. We additionally assessed the phytoremediation potential of Lolium perenne, L., Convolvulus arvensis L. and Raphanus raphanistrum L. All marsh soils exhibited natural degradation of saturated and aromatic hydrocarbons to between 85 and 95% in most cases. In contrast, asphaltenes and resins were degraded to a lesser extent (viz. 64-76% in Barizo 1, Muxía and Traba; 39-44% in Baldaio; and only 12% in Barizo 2, where flooding by the river continues to introduce balls of fuel oil into the soil). Monitoring analyses revealed natural degradation to be dependent on the thickness of the pollutant layer. Field plots sown with L. perenne L. exhibited no significant differences in fuel-oil degradation from untreated plots.

Industrial impact on marsh soils at the Bahia Blanca Ria, Argentina.

The Bahia Blanca Estuary is located in southern Buenos Aires province, Argentina. The area is linked to a petrochemical industrial complex, whose raw materials and final products contaminate the surrounding areas via atmospheric pollution and effluents, which are dumped in the estuary waters. To establish the effects of the industrial waste disposal on the nearest coastal soils, 17 samples were taken at different distances from the loading dock and the outfall pipes of the industrial complex. Later, the physicochemical characteristics of the soil samples, their hydrocarbon contents, sulfides, sulfates, Zn, Cu, and Pb were analyzed and a comparison was made to control samples, which were not affected by the industrial outfall. Hydrocarbons, Zn, Cu, and Pb contents were found at levels that modified the physical and chemical characteristics of the soils. The resistance to penetration shows that the thinner the film of water that surrounds the particles or aggregates, the smaller the migration of organic micelle, which settle on the surface of the contact material. This is demonstrated by the degree of cohesion reached by the particles and the strong influence on the index of hydrophobicity. The high porosity shows that the continuity of the porous space of the soil matrix is impeded by the presence of pollutants, which generate areas that are highly limiting to water flow. The oxidation-reduction potential and the low concentrations of soluble forms of Cu and Pb compared with their concentrations precipitated as sulfides confirm the action of the pollutants.

Proyecto del manual de normas y procedimientos en la atención inmediata del paciente pediatrico con traumatismo craneoencefálico / Project of manual of norms and the procedures in the immediate attention of the pediatric patient with craneoencefalico traumatismo

Contenido: Introducción. Planteamiento del problema. Justificación. Objetivos. Antecedentes del problema. Marco teórico. Historia de la neurocirugia. Marco conceptual. Aspectos estadisticos. Mecanismo de producción de los traumatismos craneoencefalicos. Mecanismo de la lesión. Fisiopatología. Diferencia entre niños y adultos. Diferencias fisiológicas. Diferencia del desarrollo. Clasificación. Tratamiento. Rol de la enfermera en la asistencia inmediata del paciente pediatrico con tec. Proyecto del manual de normas y procedimientos. Hipótesis. Diseño metodológico. Conclusiónes. Recomendaciónes