Browsing by Author "Akinyemi ML"

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    Dataset on noise level measurement in Ota metropolis, Nigeria
    (2019) Oyedepo SO; Adeyemi GA; Fayomi OS; Fagbemi OK; Solomon R; Adekeye T; Babalola OP; Akinyemi ML; Olawole OC; Joel ES; Nwanya SC
    Datasets contained in this article are noise level measurement carried out at 41 different locations in Ota metropolis, Nigeria. The noise readings were measured at a time interval of 30 min for each site considered using a precision grade sound level meter. The analysis was based on the noise descriptors LAeq, L10, L90, LD, TNI and NEI. Results from the study reflects that the highest and lowest equivalent noise levels (LAeq) were recorded at commercial areas (96 dB (A)) and residential areas (52 dB (A)), respectively, the background noise level (L90) has the highest and lowest values at commercial areas (77 dB (A)) and residential areas (44 dB (A)), respectively and the peak value (L10) has the highest value and lowest value at the commercial areas (96 dB (A)) and residential areas (56 dB (A)). Based on the WHO recommendations and standards, only 2 out of the 41 locations considered are under normally acceptable situation while the noise levels of other areas are not acceptable. Noise map developed in this study provides enough information for technical controls and interim legislation against environmental noise pollution in the metropolis. Moreover, considering the noise emission standards, planning and promoting the citizens awareness about the high noise risk could help to mitigate the effect of noise in Ota, Metropolis. The noise data in this study are useful as reference and guideline for future regulations on noise limit to be implemented for urban areas in Nigeria and developing countries at large.
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    Geo-investigation on groundwater control in some parts of Ogun state using data from Shuttle Radar Topography Mission and vertical electrical soundings
    (2020) Joel ES; Olasehinde PI; Adagunodo TA; Omeje M; Oha I; Akinyemi ML; Olawole OC
    Groundwater is a vital natural resource that plays a significant function in sustainability of living things on earth. Its exploration requires special skill for optimum exploitation. Shuttle Radar Topography Mission (SRTM)and Vertical Electrical Sounding (VES) were used to detectthe stratigraphy and subsurface structures controlling the groundwater system around Iju – Ota, Ogun State, Southwestern Nigeria. Nineteen (19) VES points were carried out where there were dense concentrations of lineaments and interconnected to establish the connection of the observed lineaments with groundwater occurrence in the study area using Schlumberger array, with electrode spacing of AB/2 varying from 180 to 320 m. The analysis of SRTM data revealedthe dominating structural NE-SW and NW-SE trends, which control aquifer structure. The geoelectrical parameters from the VES results were used to map the stratigraphic sequences in the study area. Six (6) units that comprisethe topsoil, lateritic clay, clayey sand, mudstone, sand (main aquifer), and shale or clay were identified in the study area. The aquiferous unit around Iju – Ota axis ranged from 30 to 80 m. Theextracted from the hill shaded SRTM data and the result of VES revealed that the thickness of the aquifer is as a result of interconnectivity of the lineaments observed in the SRTM data suggesting that the groundwater occurrence in the study area is chiefly controlled by these fractures.
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    Investigation of Radiation Levels in Soil Samples Collected from Selected Locations in Ogun State, Nigeria
    (2014) Usikalu MR; Akinyemi ML; Achuka JA
    Present study measured the terrestrial radiation and evaluated absorbed dose rates from primordial radionuclides 238U, 40K and 232Th in sixty soil samples collected from north, west, east and south of Ewekoro cement factory premises, Owowo village situated adjacent to the factory and Covenant University, Ogun State using the gamma ray spectrometry method. The gamma absorbed rate and annual effective dose equivalent were calculated so as to estimate the hazard index of the primordial radionuclides. Measured concentrations of radionuclides in Ewekoro cement factory soils were as follow: [232U 1.60±1.60 Bqkg−1 (east) - 2.56±0.08 Bqkg−1 (north), 232Th 44.78±1.83 Bqkg−1 (east) - 56.62±1.96 Bqkg−1 (north), 40K 261.54±12.67 Bqkg−1 (south) - 342.08±14.17 Bqkg−1 (east)] and Owowo village [232U 1.78±0.09 Bqkg−1 (east) - 2.62±0.08 Bqkg−1 (north), 232Th 50.07±1.93 Bqkg−1 (west) - 61.69±1.89 Bqkg−1 (north), 40K 244.11±13.38 Bqkg−1 (north) - 296.40±14.90 Bqkg−1 (south)]. These locations have higher concentration of all radionuclides than that of Covenant University soils, which are as follows: [232U 0.62±0.07 Bqkg−1 (south) - 1.07±0.06 Bqkg−1 (north), 232Th 30.23±1.87 Bqkg−1 (south) - 38.87±1.78 Bqkg−1 (east), 40K 243.35±12.57 Bqkg−1 (south) - 301.15±13.55 Bqkg−1 (north)]. The mean absorbed dose and annual equivalent effective dose is 40.88 nGyr-1 and 0.05 mSv respectively. The study found that the activity concentrations and radiological hazard index from samples from Ewekoro and the neighbourhood are consistently higher than those from Covenant University however; the values are less than the recommended safe levels.