GEOELECTRIC PARAMETERS AND ELEMENTAL COMPOSITIONS OF THE TOP SOIL OF CAMP AREA, ABEOKUTA, SOUTH WESTERN NIGERIA

Vertical Electrical Sounding (VES) and elemental composition surveys were carried out at twenty-two (22) sites atª¤? Camp Area, Alabata Road, Abeokuta, Southwestern Nigeria. This was with a view to determining depth to water«¤??bearing zones and extent of soil contamination thereby saving residents not just the pain of recurrent losses incurred for investing in dry wells, but also not to invest in contaminated waters. The study area is underlain by associated rock suites which includes pegmatite and quartz veins. Field data obtained was modeled and interpreted to obtain the geophysical parameters of the area and delineate the groundwater potential zones. Soil samples were also collected at the 22 VES points, at depths of 10 cm and 100 cm; the Global Positioning Satellite (GPS) equipment was used to obtain the geographical position of each sample point. Determination of the elemental composition of soil samples collected at the 10 cm and 100 cm depths was made using Atomic Absorption Spectrophotometer. Two heavy metals (Pb, and Cr), five major elements (K, Ca, N, P and Mg) and five trace elements (Zn, Mn, Cu, Al and Fe) were detected. It was observed that the values, representing the amount of the heavy metals, the major elements, and the trace elements were far less, mostly insignificant, at the 100 cm depth representing about the interface between the first and second layers in majority of the VES stations sampled, than at the 10 cm depth, representing the topsoil of the first layer. The implication of this is that the elements are not strictly domiciled within the area studied but may be due to runoffs as the area slopes down. Moreover, going by the values at the 100 cm depth, the elements may not be capable of percolating into the underground water zones in the area of study, and thus might not have contaminated the underground water. Thus, at the current level, the underground water can be adjudged safe for human consumption.ª¤

Caractérisation physico-chimique et évaluation du risque d’eutrophisation du lac Nokoué (Bénin)

L’ étude, menée sur deux (2) ans (2006 et 2007) , a permis de faire le bilan hydrologique du lac Nokoué et de connaitre la qualité physico-chimique des eaux du lac en vue d’offrir les éléments de base pour une modélisation écologique future du système. Les données historiques observées au niveau des stations de Bonou et de Sô – Ava, de même que des mesures ponctuelles des débits à l’ADCP des tributaires à leurs entrées dans le lac, ont été exploitées pour réaliser ce bilan hydrologique. Les saisons (saison sèche et période de hautes eaux) ont été prises en compte dans cette évaluation. Les résultats du bilan hydrologique montrent que le débit moyen d’eau douce reçu par le lac en période de hautes eaux (Août à Octobre) est de 216 m3/s essentiellement apporté par le fleuve Ouémé, le plus long fleuve du Bénin qui traverse le pays du nord au sud. Cette valeur tombe à 49m3/s en saison sèche avec 86% du débit apporté par la Sô. En saison sèche, la Sô à Ganvié a le taux le plus important de charge organique (53% de DBO). Pour le phosphore en saison sèche le plus fort taux est obtenu au niveau du fleuve Ouémé à Totchè (42%). En période de hautes eaux (Août à Octobre) il est observé un effet de dilution des apports. En terme de charges nutritives apportées par les systèmes d’assainissement, les résultats obtenus sont pour Cotonou et Calavi 360 kg/j –P et 840 kg/j – N et pour Ganvié 150 kg/j - P et 700 kg/j –N; les apports des « Acadjas » donnent 2,3 – 2,9 kg/j P et 29 – 36 kg/j N. Les principaux résultats obtenus pour la caractérisation physico – chimique se présentent comme suit :- une intrusion saline est très remarquable en saison sèche, ainsi à Ganvié on passe de 0 g/L en période de hautes eaux à 2,5 g/L en saison sèche ; le pH moyen varie ente 6,6 et 7,5 pour les eaux du fond du lac et entre 6,9 et 7,8 pour les eaux de surface du lac. Le pH varie très peu entre le fond du lac et la surface du lac ; l’évaluation du risque d’eutrophisation à partir de l’outil de diagnostic d’Ifremer, classe la quasi-totalité des eaux dans la zone rouge (i.e mauvaise). Les valeurs des nutriments azotés et phosphorés sont largement supérieures aux valeurs limites indiquées par le système de classification de l’Organisation de Coopération et Développement Economique (OCDE). Les eaux du lac sont eutrophes. Cette eutrophisation se manifeste par la prolifération des jacinthes d’eau. On note une évolution saisonnière du système. Du point de vue des facteurs de contrôle des jacinthes d’eau, il ressort que les nutriments contrôlent le développement des jacinthes lorsque la salinité n’inhibe plus la croissance des jacinthes, c’est-à-dire de juillet à janvier.Mots clés: Bilan hydrologique, lac Nokoué, charges polluantes, eutrophisation, jacinthe d’eau, intrusion salin

IRAS 21391+5802: The Molecular Outflow and its Exciting Source

We present centimeter and millimeter observations of gas and dust around IRAS 21391+5802, an intermediate-mass source embedded in the core of IC 1396N. Continuum observations from 3.6 cm to 1.2 mm are used to study the embedded objects and overall distribution of the dust, while molecular line observations of CO, CS, and CH3OH are used to probe the structure and chemistry of the outflows in the region. The continuum emission at centimeter and millimeter wavelengths has been resolved into three sources separated about 15 arcsec from each other, and with one of them, BIMA 2, associated with IRAS 21391+5802. The dust emission around this source shows a very extended envelope, which accounts for most of the circumstellar mass of 5.1 Msun. This source is powering a strong molecular outflow, elongated in the E--W direction, which presents a complex structure and kinematics. While at high outflow velocities the outflow is clearly bipolar, at low outflow velocities the blueshifted and redshifted emission are highly overlapping, and the strongest emission shows a V-shaped morphology. The outflow as traced by CS and CH3OH exhibits two well differentiated and clumpy lobes, with two prominent northern blueshifted and redshifted clumps. The curved shape of the clumps and the spectral shape at these positions are consistent with shocked material. In addition, CS and CH3OH are strongly enhanced toward these positions with respect to typical quiescent material abundances in other star-forming regions.Comment: 41 pages, including 11 figures, accepted for publication in ApJ (July 1); available at http://www.am.ub.es/~robert/Papers.html#las

Prise en charge communautaire des maladies de l’enfance à Madagascar : de l’espoir au dysfonctionnement

En 2014, l’UNICEF avec le Ministère de la santé publique (MINSAP) a procédé au renforcement du programme de prise en charge des maladies de l’enfance au niveau communautaire. Bien que le programme soit efficace en ce sens qu’il contribue à l’augmentation du nombre d’enfants traités et diagnostiqués, la qualité de la prise en charge n’est pas satisfaisante (42,6% des agents de santé communautaires effectuent encore des erreurs). L’objectif de cet article est d’identifier les causes de ce dysfonctionnement

Public health implications of endocrine disrupting chemicals in drinking water and aquatic food resources in Nigeria: A state-of-the-science review

This state-of-the-science review is aimed at identifying the sources, occurrence, and concentrations of EDCs, including potential public health risks associated with drinking water and aquatic food resources from Nigerian inland waters. A total of 6024 articles from scientific databases (PubMed, Scopus, Web of science, ScienceDirect, Google Scholar, and African Journals Online) were identified, out of which, 103 eligible articles were selected for this study. Eleven (11) classes of EDCs (OCPs, PCBs, PBDEs, PAHs, BPA, OTs, PEs, PCs, PPCPs, sterols and n-alkanes) were identified from drinking waters, river sediments and aquatic food species from Nigerian rivers, showing that OCPs were the most studied and reported EDCs. Analytical methods used were HPLC, LC-MS/MS, GC-FID, GC-ECD and GC–MS with all EDCs identified to originate from anthropogenic sources. Carcinogenic, mutagenic, and teratogenic effects were the highest (54.4 %) toxicological effects identified, while reproductive/endocrine disruptive effects (15.2 %) and obesogenic effects (4.3 %) were the least identified toxicological effects. The targeted hazard quotient (THQ) and cancer risk (CR) were generally highest in children, compared to the adult populations, indicating age-specific toxicity. PEs produced the highest THQ (330.3) and CR (1.2) for all the EDCs in drinking water for the children population, suggesting enhanced vulnerability of this population group, compared to the adult population. Due to associated public health, wildlife and environmental risk of EDCs and their increasing concentrations in drinking water and food fish species from Nigerian inland waters, there is an urgent need for focused and strategic interventions, sensitization and policy formulation/implementation towards public health and aquatic food safety in Nigeria.publishedVersio