MEASUREMENT OF ACTIVITY CONCENTRATIONS OF NATURAL RADIONUCLIDES IN THE TOP SOIL OF UNIVERSITY OF AGRICULTURE, ABEOKUTA, (UNAAB) FARMS

The natural radioactivity levels in the soils of University of Agriculture Abeokuta farms were measured.        20 soil samples were collected to a depth of about 10cm in twelve different farmlands within UNAAB        community.    The   average  activity  concentrations  obtained  for  the  three  radionuclides  were        520.13±32.06 Bq/kg for 40K, 33.66±23.27 Bq/kg for238U and 49.83±15.61 Bq/kg for232Th, respectively.        The distributions of these radionuclides were found to be uneven. The value of Uranium-238 was the        same at locations 4 and 16 but not detectable at locations 9 and 11, respectively. The average values        of the absorbed dose rates in air of each radionuclides were found to be 21.84 nGy/hr for 40K, 14.99        nGy/hr   for  238U   and   33.19   nGy/hr   for  232Th.   The   baseline   average   outdoor   annual   effective   dose        equivalent in UNAAB farms due to the radioactivity concentrations was found to be 86.92±28.37mSv/        yr. This value can be taken as representing the baseline values of natural radioactivity as no artificial        radionuclide was detected at any of the locations visited.&nbsp

MEASUREMENT OF RADIATION DOSE IN SELECTED CEMENT STORES IN ABEOKUTA, OGUN STATE, USING GM SURVEY METER

Measurements were carried out using a Geiger Muller Survey Meter and a Global Positioning System (GPS) to find  the outdoor absorbed dose rates in selected cement stores in Abeokuta, Ogun State, Nigeria. The outdoor  absorbed dose rates  (control sites 10m away from cement depot) ranged from 400 nGy/hr) (Sapon) to 740 nGy/hr (Adatan) with the mean 554.7 ± 0.08 nGy/hr  and the indoor absorbed dose rate (store) ranged from 740 nGy/hr  (Lafenwa1&2) to 1240 nGy/hr (Isale-Ake) with the mean 909.3 ± 16 nGy/hr. The corresponding annual effective dose rates for the control sites ranged from 1.13 mSv/yr (sapon) to 2.09 mSv/yr (Adatan) with the mean 1.57 ± 0.32  mSv/yr, while it ranged from 2.45 mSv/yr (Lafenwa1&2) to 4.11 mSv/yr (Isale ake) for the cement depots  with the mean 3.01 ± 0.52 mSv/yr. It has been revealed from this study that cement may enhance exposure to radiation, since the value of the absorbed dose rates in the stores are higher than thoseof the control sites. The values for the annual effective dose calculated are higher than 1mSv/yr. &nbsp

ABSORBED DOSE RATES ABOVE SOILS AND ROCK OUTCROPS IN SELECTED AREAS OF ABEOKUTA, NIGERIA

Outdoor absorbed dose rates were measured in selected areas of Abeokuta in Nigeria; some with rock outcrops and others with soil overburden. Measurements were carried out using a Geiger Muller Survey Meter and a Global Positioning System (GPS). Result shows absorbed dose rates ranged from 1.0 x 103 to 1.3 x 103 nGy/hr among the rock outcrop areas and from 0.6 x 103 to 0.8 x 103 nGy/hr among the soil -covered areas. The average absorbed dose rate was 1180 ±3 nGy/hr for the rock outcrop areas and 689 ±3 nGy/hr for the soil -covered areas and assuming 0.4 occupancy factor, the corresponding average annual effective dose rates were calculated to be 2.89 ± 0.01 mSv/yr for the rock outcrop areas and 1.69 ± 0.01 mSv/yr for the soil –covered areas based on occupancy factor of 0.4. The mean annual effective dose rates for both the rock outcrop and soil covered areas were  found to be higher than 1mSv/yr, the recommended dose limit for the public.     &nbsp

IMPLEMENTATION OF THE ROOT BISECTION COMPUTATIONAL PHYSICS METHOD FOR THE DETERMINATION OF ROOTS OF NON-LINEAR EQUATIONS USING JAVA

Advancement in programming and language development has made possible improved efficiency and accuracy in solving numerical problems and hence the numerical computation of physical problems as used in Computational Physics. Hitherto, languages such as Basic, Fortran, C, among others, have commonly been employed in solving numerical problems. In this work, Java, a modern object oriented language was deployed in solving some physical problems, specifically, determination of roots of non-linear equations using the Root-Bisection Method. A comparison between results obtained showed faster convergence and greater accuracy using Java than as obtained using Fortran.     &nbsp

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¤

COMPARISON OF ACTIVITY CONCENTRATIONS OF NATURAL RADIONUCLIDES IN SOILS COLLECTED AT DIFFERENT DEPTHS OF SELECTED HAND-DUG WELLS IN ABEOKUTA

This study was aimed at measuring and comparing the activity concentration of soil samples collected from some selected hand – dug wells with their corresponding depths of collection in Abeokuta metropolis. Total of twenty (20) soil samples were collected from hand-dug wells in five sites (Obada, Adigbe, Kuto, Olorunsogo, and Obantoko) within Abeokuta with four (4) soil samples from each hand-dug well at the surface, (0.0m) through to 2.25m depth. Gamma ray spectroscopy with High Purity Germanium (HPGe) detector was used for the measurements. The average activity concentrations obtained for the three natural radionuclides 226Ra, 232Th and 40K in Bq/Kg are 34.31 ± 2.01, 128.73 ± 4.41 and 152.31 ± 2.59 respectively at depth 0.00 m (surface), 23.00 ± 1.61, 68.39 ± 3.24 and 191.08 ± 3.11 respectively at depth 0.75 m, 31.52 ± 2.21, 145.37± 4.95 and 375.56 ± 5.50 respectively at 1.50 m and lastly 28.57±1.70, 95.61 ± 3.71 and 181.10 ± 3.94 respectively at 2.25 m depth. The world average activity concentrations for 226Ra, 232Th and 40K are given to be 35 Bqkg-1, 30 Bqkg-1 and 400 Bqkg-1 respectively (UNSCEAR 2000). 232Th showed  higher average values than the world’s average while averages of 226Ra and 40K were lower but most of the activity concentration values obtained in some of the locations are higher than the world’s average values, especially 226Raand 232Th in the soil samples.

Investigation and Comparison of Heat Generated by Coloured Metallic Plates in Response to the Emissive and Absobtion Power of the Surfaces of the Coloured Plate

A colour test was carried out to determine the rates of absorption and emission of infrared radiation by coloured hollowed metallic plates which result in increase in temprature of the holllowed plates at maximum radiation of 750 Wm-2 at Abeokuta 7.198305 and Longitude 3.439533 during the month of March 2013. Five hollow metallic plates of different paint colours (black, green, red, blue and white) were exposed to sunlight simultaneously and the temperature generated in each plate was recorded using a data logger. A wooden box that was divided into five cavities was constructed and lagged with wood shavings to provide insulation and the five coloured hollowed metallic plates of dimension d=4h were inserted in it. The choice dimension d=4h is to minimise shading of the inside of the plate (d is the diameter of each of the plates and h is the height) the top of the plates were covered with a 5 mm thick glass. The top cover plates were securely laid tightly to both the wooden box and the tip of the plates to prevent heat loss to the surrounding and also from crossing from one plate to another.  This arraignment is similar to that of a flat plate collector and calorimeter experiment. The centre of each of the plate was connected to five probes of a data logger and the temperature of changes inside the plates are logged and recorded

MODELLING OF 226Ra ACTIVITY CONCENTRATIONS ALONG OGUN RIVER, SOUTH WESTERN NIGERIA

This work was aimed at generating a model using least square approximation technique to predict values of activity concentrations of 226Ra in any location along Ogun river in Nigeria using experimental data. Sediment samples were collected in thirty two locations along the river of about 400 km in length. NaI(Tl) gamma-ray spectrometer system was used to obtain activity concentrations of 226Ra.The aver-age value of activity concentration of 226Ra in the sediment samples from the upper region through the middle to the lower region of the river was found to be 12.65 ± 3.48 Bq/kg, having values ranging from 5.57 ± 2.36 Bq/kg (at Ekerin) to 20.40 ± 4.52 Bq/kg (at Sokori). From this work, it was observed that the generated model and experimental data could be used to predict values of activity concentrations of 226Ra in any location along the river once the latitude and longitude (position) are known. Statistical tests on the model also showed that there were no significant differences between the experimental and predicted data of 226Ra and that 98.70% of the experimental data were predicted by the model

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