Microbial and physicochemical properties of ground water of Ilaro, South-West, Nigeria

The present study was carried out to determine the microbial quality and physicochemical properties of ground water in Ilaro, a semi-urban settlement. Plate count agar (PCA), MacConkey broth and eosin methylene blue agar (EMB) were used in the microbial analysis. The results showed that the most probable number (MPN) ranges from 0 – 50 per 100 ml while the total viable count (TVC) ranged from 0.07 x 10² – 4.12 x 10² cfu ml-1. Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis, Escherichia coli,Enterobacter aerugenosa and Micrococcus luteus were isolated. The physicochemical properties measured using their respective meters showed that the water was acidic. It was concluded that treatment before consumption is necessary to avoid borne diseases

Model prediction and climatology of aerosol optical depth (τ550) and angstrom exponent (α470-660) over three aerosol robotic network stations in Sub-Saharan Africa using moderate resolution imaging spectroradiometer data

The spatial and temporal variations of aerosol optical depth at 550 nm (τ550) and Angstrom exponent derived from 470 and 660 nm (α470-660) over Nairobi (NAI), Skukuza (SKU) and Ilorin (ILO) Aerosol Robotic Network (AERONET) stations in sub-Saharan Africa, as recorded by Moderate Resolution Imaging Spectroradiometer (MODIS) satellites for fifteen years (2000-2015), were examined in relation to their climatologies and prediction. The MODIS measurements of τ550 and α470-660 from aqua (MYD04) and terra (MOD04) satellites were used in this study. Retrievals of τ550 for both satellites were validated with AERONET τ550 for the same period. The validation results showed that they compare favourably over the three stations, but MOD04 performed better than MYD04 data in NAI and ILO for τ550. This shows that the τ550 of NAI and ILO are best captured using the MOD04 data while that of SKU is best with MYD04. It was also discovered that MODIS underestimated AERONET τ550 data over NAI and SKU. The most polluted station is ILO while the least polluted one is NAI. Similarly, the station with the highest concentration of absorbing aerosols is NAI and the least was observed in ILO. The aerosol climatology shows that the most polluted months in NAI, SKU and ILO are October, June and March respectively. On the other hand, February, November and March has the highest amount of scattering aerosols in the atmosphere for NAI, SKU and ILO respectively. The highest amount of absorbing aerosols was found, respectively, in the months of June, June and August. The generated time series (TS) models are all good, though a general underestimation of the parameters by the models was also observed. Keywords: Aerosol optical depth, Angstrom exponent, MODIS, Time series, sub-Saharan Afric

First Principles Investigation of the Influence of Varied Cr Atom on Band Structure and Magnetic Moment of Rutile SnO2

Authors: Funmilayo  Ayedun, Etido P. Inyang  and Efiong A. Ibanga Received 18 November 2020/Accepted 24 December 2020 The electronic and magnetic properties of SnO2 doped with various compositions of chromium atoms are reported. Studies on magnetic property of CrxSn1-xO2 compounds features possible room temperature ferromagnetism which increased nonlinearly as Sn atom is replaced with Cr atom, at x = 0.25( 1.9976 ), x =  0.50 ( 3.9309 ), x = 0.75( 5.8831 ) and x = 1.00 (7.821 ). The magnetic moment and bandgap energy of undiluted SnO2 were compared at x = 0. The addition of Cr atom into SnO2 enhanced the shift from pure binary nonmetallic system to ternary metallic compound. The direct energy gaps decrease from x = 0 to 0.5, and increase from x = 0.75 to 1.0

ASSESSMENT OF POLLUTION HAZARDS OF GROUNDWATER RESOURCE IN ABEOKUTA NORTH LOCAL GOVERNMENT AREA, OGUN STATE, SOUTHWESTERN NIGERIA

Pollution of wells and borehole water, either from point or non-point sources, has become a matter of health concern both in urban and rural areas. Groundwater is tapped for domestic uses through the con-struction of hand dug wells and boreholes. However, while providing an alternative to the public water supply sources; most of the boreholes are often located too close to possible contamination sources. Various land use and human activities such as solid waste landfills, cemetery and animal wastes, among others can result in ground water contamination. In an open or buried dumping solid waste or sanitary landfill, the organic and inorganic by-products resulting from the decomposition of wastes are leached out by the infiltration of rainfall. A release of leachate to the surrounding soil without proper collection and treatment could contaminate groundwater resources. Many of the wells and boreholes in the study area were found to be indiscriminately located and scattered among such impairing lands/features. This study was therefore aimed at assessing the pollution hazards and vulnerability of groundwater resource in Abe-okuta North Local Government Area (LGA) by sampling some boreholes from selected locations in the area. Water samples were collected and analyzed for water quality parameters using standard proce-dures. The parameters determined were Turbidity, Temperature, Electrical Conductivity (EC), pH, Total Dissolved Solids (TDS) Total Suspended Solids (TSS), Total Solids (TS), Total hardness, cations {Potassium (K), Sodium (Na), Calcium (Ca), Magnesium (Mg), Manganese (Mn), iron (Fe)}, anions {Chloride (Cl-), Nitrate (NO3-), Sulphate (SO42-), Phosphate (PO43-)}, and heavy metals {lead (Pb2+), Zinc (Zn2+), Copper (Cu2+)}. Results were subjected to statistical evaluations using SPSS 18.0 for descriptive statistics and Analysis of Variance (ANOVA). It was observed that the elemental parameters in the bore-holes sampled have mean values of the concentrations of Fe2+, Na+, Cl- , SO42-, Pb2+, Mn2+, Cu2+ and Zn2+ higher during the wet season relative to dry season. For the physico-chemical parameters, it was equally observed that parameters such as EC, TDS, TS, TSS were higher during the wet season than dry season while turbidity, temperature, pH and total hardness were higher during dry season than in the wet season. Water quality parameters such as Fe2+, Pb2+, NO3-, and EC have mean values greater than World Health Organization and NESREA maximum permissible standards for drinking water. Elevated values of these parameters are of great concern to public health when the water from these boreholes is consumed without treatment by people. It is recommended that well and borehole waters in this area be adequately treated before consumption using advanced inorganic removal techniques such as Nano-filtration and Reverse Osmosis to safeguard human health in the study area.Keywords: Boreholes, pollution, water quality, public health, physico-chemica

Häufigkeit von und Mortalität bei Hochbaueinstürzen

Der Beitrag befasst sich mit der Bestimmung der Einsturzhäufigkeiten von Hochbauten bzw. Gebäuden für verschiedene Länder und Regionen. Zunächst werden entweder direkte Angaben des Gebäudebestands verwendet oder Gebäudebestände über Ersatzparameter abgeschätzt. Die Einsturzereignisse wurden aus der Tagespresse oder aus der Literatur entnommen. Neben der Berechnung der Einsturzhäufigkeiten werden auch die Mortalitäten durch Gebäudeeinstürze bestimmt. Dazu wurden wiederum Angaben aus der Tagespresse oder Literatur verwendet. Außerdem erfolgt eine kurze Diskussion der Ursachen der Gebäudeeinstürze. Für Industrieländer ergibt sich eine mittlere jährliche Einsturzhäufigkeit von 2,4 × 10–7 pro Jahr und für Entwicklungsländer von 4,7 × 10–6 pro Jahr. Die mittlere Mortalität liegt bei 9,8 × 10–8 für die Industrieländer und 1,5 × 10–6 pro Jahr für die Entwicklungsländer. Die Ursachen von Gebäudeeinstürzen liegen in den Entwicklungsländern – und damit bei der überwiegenden Anzahl der Einstürze – in der ungenügenden Qualifikation der Beteiligten