5 research outputs found
Geo-investigation on groundwater control in some parts of Ogun state using data from Shuttle Radar Topography Mission and vertical electrical soundings
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
Spatial Distribution of Gamma Dose Rates in the Marine Environment of Unumherin Community in Niger Delta, South-South, Nigeria
This work investigates the radioactivity distribution of coastal polluted areas of
Unumherin Community in Niger Delta, Nigeria. The measurement of the outdoor dose rate of
the polluted coastlines was carried out using calibrated hand-held gamma detector, (RS-125
Gamma-Spec). The spatial distribution of gamma dose rate indicates the hotspot at location 4
with a value of 100 nGy/h. Maximum and minimum values of the absorbed dose-rate was
observed in location 4 with the value of 100 nGyℎ−1 and location 15 with the value of 2
nGyℎ−1, respectively. This is an indicative that the risk of ionizing radiation exposures is
much higher for location 4 than other locations. This higher value of 100 nGyℎ−1 is far more
than the recommended limit of 59.00 and 84.00 nGyℎ−1 provided by UNSCEAR, 2000. The
community requires much more radiological monitoring for the safety of human and
ecosystem
Radioactivity distributions and biohazard assessment of coastal marine environments of niger-delta, Nigeria
ABSTRACTThe Unumherin community in Nigeria’s Niger Delta is home to coastal marine polluted zones, and this research examines the radioactivity distributions and biohazard in the coastal environment. The activity concentrations of 40K, 238U, 232Th, as well as the outdoor dose rate of contaminated coastlines were measured using a calibrated RS-125 Gamma-Spec and a NaI(Tl) gamma-detector. The laboratory examination of sediments, water, and fish from the same coastal region – Clarias gariepinus Pseudotropheus elongated Oreochromis niloticus and Stromateus fiatola – was combined with the in-situ observations of gamma dose rates. With a value of [Formula: see text], the hotspot at site 4 is shown by the geographic distribution of gamma dose rates. The findings showed that the activities of the primordial radionuclides varied, with average values for the sediments and water exceeding suggested limits. Similarly, the corresponding mean hazard indices mostly exceeds the allowable limits. The species specificity of the fish species accounts for the variation in the mean concentrations of 40K, 238U and 232Th. C. gariepinus, having accumulated higher concentrations of 40K and 238U, may be the first to elicit health hazards in the future if pollution continues unmonitored. Hence, continuous monitoring of the aquatic environment alongside is highly recommended