Extraction chimique des métaux lourds des argiles de la décharge finale d’Agoè-Nyivé au Togo

A sufficiently thick layer of clay, continuous and homogeneous under a deposit of waste constitutes a barrier preventing pollution of the water table if the leachates are well drained on its surface and then properly treated.Since the exploitation of the landfill of Agoè-Nyivé (Lomé), very few studies have been carried out on the state of pollution, especially of heavy metals, of the base layer of the clay-filled landfill.The objective of this work, is to evaluate the content of heavy metals (Pb, Cd, Ni, Cu and Zn) in the base layer samples of the final discharge Agoè-Nyivé and evaluate their potential migration to the depths.The qualitative analysis of the clay samples through X-ray diffraction shows the existence of quartz, carbonate and kaolinite with varying proportions from one sample to another. Complementary analysis of the infrared spectroscopy shows spectra that reveal the presence of a kaolinite with bands observed in the vibrational region of the hydroxyls located at 3698, 3652 and 3622 cm-1.The heavy metal contents in the clay samples show that lead and nickel have a strong propensity to bind respectively to the reducible and residual fraction. On the other hand, cadmium has an almost equal distribution in the four fractions while zinc is more present in the exchangeable and acid-soluble fraction with percentages ranging from 18.75 to 76.67 %.The strong presence of heavy metals found in soil fractions where they can be easily mobilized shows the risk of their migration to the depths.Une couche d’argile suffisamment épaisse, continue et homogène sous un dépôt de déchets constitue une barrière empêchant la pollution de la nappe phréatique si les lixiviats sont bien drainés à sa surface puis correctement traités. Depuis l’exploitation de la décharge d’Agoè-Nyivé (Lomé), très peu d’études, ont été réalisées sur l’état de pollution notamment en métaux lourds de la couche de base de la décharge composée d’argile.L’objectif de ce travail est d’évaluer la teneur de certains métaux (Pb, Cd, Ni, Cu et Zn) dans les échantillons de couches de base de la décharge finale d’Agoè-Nyivé afin d’évaluer leur potentielle migration vers la nappe.L’analyse qualitative des échantillons d’argile à travers la diffraction des rayons X, montre l’existence de quartz, de carbonates et de kaolinite avec des proportions variables d’un échantillon à l'autre. Une analyse complémentaire notamment la spectroscopie infrarouge montre la présence d’une kaolinite avec des bandes observées dans la région de vibration des hydroxyles situées à 3698, 3652 et 3622 cm-1.Les teneurs en métaux lourds analysées après extractions sélectives montrent que le plomb et le nickel ont une forte propension à se lier respectivement à la fraction réductible et résiduelle. Par contre, le cadmium a une répartition quasi-égale dans les quatre fractions alors que le zinc est plus présent dans la fraction échangeable et acido-soluble avec des pourcentages variant de 18,75 à 76,67 %.La forte présence des métaux lourds constatée dans les fractions de sol où ils peuvent être facilement mobilisables montre le risque de leur migration vers les profondeurs

Dissolution mechanism studies of rock phosphates of hahotoé-kpogamé (Togo) by the natural humic substances.

International audienceIn the framework of natural phosphate of Hahotoé-Kpogamé (Togo) valorization, a conductimetric study of kinetics of the attack by organics and mineral acids is undertaken at different pH. The mechanisms of complexation of calcium by two humic acids, one extracted in a soil (AHSB) and second in compost (AHC) was carried out. Monitoring of rock dissolution has realised by P2O5 measurement in filtrates, using colorimetric method. The complexation of two humic acids of different origins with the ions Ca2+ by conductimetric and potentiometric methods were carried out. According to the results obtained, importance of rock dissolution depends to solution's acidity whatever the acid origin (organic or mineral). Nonetheless, for humics acids solutions, phosphate dissolution continues in slightly acidic and alkaline solutions. The method of neutralization of the acids humic by the soda based on the derivative of the curve potentiometric made it possible to characterize and to compare the forces of the various acid functions organic materials of different origins has to complex the metal cation

Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

Aims The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation. Methods and results Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (inhospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, prehospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin. Conclusion The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality