Residual pollution and vegetation distribution in amended soils 20 years after a pyrite mine tailings spill (Aznalcóllar, Spain).

The present work assesses the residual pollution in the Guadiamar Green Corridor (SW, Spain) after a long-term aging process (18 years) since the accident of the Aznalcóllar pyrite mine. We have focused on the study of trace elements (Cu, Zn, Cd, As and Pb) in soils, their fractionation and the transference to the surrounding vegetation. The residual polluted areas are characterized by scattered plots with absence of vegetation, presenting high concentrations of trace elements, acidic pH and low organic carbon content. Surrounding these polluted plots, two vegetation gradient belts are clearly identified by changes in plant cover and richness. The inhibition of plant growth in the bare soils is related to the highest mobility of soluble and exchangeable Cu, Zn and Cd forms, which significantly decrease with the distance to the polluted plots. Plant richness and cover show differences between belts; bioaccumulation of trace elements in plants also differs, with a preferential accumulation in roots. Despite the low bioavailability of As and Pb in soils, bioaccumulation factors in plants for these elements are significantly higher in belt 1 in relation to belt 2. High Cu and Cd potential toxic concentrations in aerial parts of vegetation are found, posing a risk for livestock and a potential entrance to the food-chain. On the other hand, Lamarckia aurea (L.) Moench (in belt1) and Trifolium campestre Schreb. (in belt2) were the most dominant species in severely polluted soils. Elevated concentrations of trace elements in the vegetation growing in the area indicate plant adaptation mechanisms to live in these severely polluted soils, which can be used as a good bioindicator of pollution in similar polluted areas.

Evaluation of remediation techniques in soils affected by residual contamination with heavy metals and arsenic.

Residual soil pollution from the Aznalcóllar mine spill is still a problem in some parts of the affected area, today converted in the Guadiamar Green Corridor. Dispersed spots of polluted soils, identified by the absence of vegetation, are characterized by soil acid pH and high concentrations of As, Pb, Cu and Zn. Ex situ remediation techniques were performed with unrecovered soil samples. Landfarming, Composting and Biopiles techniques were tested in order to immobilize pollutants, to improve soil properties and to promote vegetation recovery. The effectiveness of these techniques was assessed by toxicity bioassays: Lactuca sativa L. root elongation test, Vibrio fischeri bioluminescence reduction test, soil induced respiration test, and Eisenia andrei survival and metal bioaccumulation tests. Landfarming and Composting were not effective techniques, mainly due to the poor improvement of soil properties which maintained high soluble concentrations of Zn and Cu after treatments. Biopile technique, using adjacent recovered soils in the area, was the most effective action in the reduction of soil toxicity; the improvement of soil properties and the reduction in pollutants solubility were key to improve the response of the tested organisms. Therefore, the mixture of recovered soils with polluted soils in the areas affected by residual contamination is considered a more suitable technique to reduce the residual pollution and to promote the complete soil recovery in the Guadiamar Green Corridor.

Acción del maleato de perhexilina sobre la curva de disociación de la hemoglobina en pacientes coronarios / Action of the perhexiline maleate on the dissociation curve of the hemoglobin in coronary patients

La desviación hacia la derecha de la curva de disociación de la hemoglobina (CDO) aumenta la liberación de O2 a los tejidos y podría ser un mecanismo útil en la cardiopatía isquémica. Algunos fármacos, como el propranotol, son capaces de producir este efecto. Con objeto de comprobar si el maleato de perhexilina tuviera alguna acción sobre la CDO, se estudiaron once enfermos coronarios tratados con 100-200 mg/día (media, 163). Se analizó la P50 y los niveles de 2,3 DPG antes de comenzar el tratamiento, a las cuatro horas y a los ocho días del inicio del mismo. La P50 pasó de 25,65 + ou - 0,97 mmHg (-x + ou - SD) a 25,93 + ou - 0,99 y a 26,07 + ou - 1,004. Por su parte, el 2,3 DPG aumentó de 14,35 + ou - 1,6 micromoles/g Hb a 14,67 + ou - 1,58 y 14,81 + ou - 1,39. Estas variaciones no fueron estadisticamente significativas. Se concluye que el maleato de perhexilina, con las pautas aqui empleadas, no altera de modo significativo la COD; existe sin embargo cierta tendencia al aumento progresivo y paralelo de P50 y 2,3 DPG que, para hacerse más evidentes, podrían requerir mayores dosis de la droga, más tiempo de tratamiento o un número de pacientes superior

Acción del maleato de perhexilina sobre la curva de disociación de la hemoglobina en pacientes coronarios / Action of the perhexiline maleate on the dissociation curve of the hemoglobin in coronary patients

La desviación hacia la derecha de la curva de disociación de la hemoglobina (CDO) aumenta la liberación de O2 a los tejidos y podría ser un mecanismo útil en la cardiopatía isquémica. Algunos fármacos, como el propranotol, son capaces de producir este efecto. Con objeto de comprobar si el maleato de perhexilina tuviera alguna acción sobre la CDO, se estudiaron once enfermos coronarios tratados con 100-200 mg/día (media, 163). Se analizó la P50 y los niveles de 2,3 DPG antes de comenzar el tratamiento, a las cuatro horas y a los ocho días del inicio del mismo. La P50 pasó de 25,65 + ou - 0,97 mmHg (-x + ou - SD) a 25,93 + ou - 0,99 y a 26,07 + ou - 1,004. Por su parte, el 2,3 DPG aumentó de 14,35 + ou - 1,6 micromoles/g Hb a 14,67 + ou - 1,58 y 14,81 + ou - 1,39. Estas variaciones no fueron estadisticamente significativas. Se concluye que el maleato de perhexilina, con las pautas aqui empleadas, no altera de modo significativo la COD; existe sin embargo cierta tendencia al aumento progresivo y paralelo de P50 y 2,3 DPG que, para hacerse más evidentes, podrían requerir mayores dosis de la droga, más tiempo de tratamiento o un número de pacientes superior (AU)

Pulmonary function and tissue oxygenation studies during anesthetic induction with etomidate.

The modifications of pulmonary function and peripheral oxygenation arising during anesthetic induction with Etomidate were studied in 36 unpremedicated patients programmed for elective surgery. The evaluation was carried out through measurement of ventilatory parameters and of the blood gases and oxygen saturation in arterial and mixed venous blood, calculation of the cardiac output, and derivation of data of peripheral oxygenation. A global reduction of the minute volume was observed with a minimal effect on the blood-gas values. The arterial blood oxygenation was reduced during the anesthesia time due to increased alveolo-arterial oxygen gradients and to increased intrapulmonary shunt. The tissular oxygenation data evidenced no significant alterations.

The influence of carboxyhaemoglobin on the oxygen-binding capacity of blood. A comparison of manometric (Van Slyke) and optical (Co-Oximeter) measurements.

Oxygen content measurements determined optically by the Co-Oximeter correlated closely with those obtained using the manometric technique of Van Slyke. In those samples with a high content of carbon monoxide, the agreement between the two methods could be improved, by taking into consideration the concentration of carboxyhaemoglobin (COHb), since this plays no part in oxygen transport. The calculated values of the oxygen-binding capacity varied widely, with mean values less than the theoretical figure of 1.39 ml O2/g Hb. This difference was greater in those samples with a higher content of COHb. When the amount of haemoglobin combined with COHb was taken into consideration the mean corrected values approximated to the theoretical value of 1.39, thus supporting this as the mean value for the oxygen-binding capacity of haemoglobin, although the large individual variability persisted.