Department of Geology and Mineral Sciences

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Browsing Department of Geology and Mineral Sciences by Author "Olusola Johnson Adedeji"

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    Assessment of Heavy Metals Pollution in Sediments from Ologe Lagoon, Agbara, Lagos, Nigeria
    (Journal of Geoscience and Environment Protection, 2019) Adeyemi Moyosoluwa Odunayo; Olusola Johnson Adedeji; Akpobasah Oghenemaro; Adidi Nathan Eyituoyo; Shelle Rafiu Olaniyi Dada
    This study was carried out to assess the level of heavy metals pollution in Ologe Lagoon, Agbara, Lagos, Nigeria. The Lagoon receives effluents from industries in the Agbara Industrial Estate. Cored Soft sediments were retrieved from six random sampling points within the Lagoon and labeled (S1, S2, S3, S4, S5 and S6). Subsamples of the sediments were prepared and analyzed for heavy metal concentration. The result from the heavy metal analysis of the sediments shows that average concentration of Mn, Zn, Cr, Ni, Cr, Ni, Co, Cu and Pb in the samples was 278.1 ppm, 21.7 ppm, 14.2 ppm, 6.6 ppm, 6.4 ppm, 6.4 ppm and 4.4 ppm, respectively. The correlation between the heavy metals varies from 0.71 to 0.98 shows that they have a strongly positive degree of association which suggests that they are from the same source. The geo-accumulation values for Cu in all stations ranged between (1 - 2.8 ppm) and it can be deduced that the sediments are moderately to strongly polluted. Pb varies between 1 and 2.1 suggesting that the sediments are moderately polluted. Zn exhibits strong pollution levels with a range from 2.5 and 3.5 ppm. Co is moderately polluted with 1.5 - 2.4 while Mn shows the highest level of pollution in all stations with Igeo values ranging between 4.1 and 5.8. This study showed that the Lagoon accumulates heavy metals as a result of anthropogenic activities evident in the dumping of municipal, sewage, industrial waste in the environment and domestic activities such as auto mobile transportation and mechanic repair workshop. Based on sediment quality guidelines, the Ologe Lagoon level of pollution ranged from Cu > Pb > Zn > Ni > Co > Mn > Cr > Al with Mn having the highest level of pollution.
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    Geotechnical and GIS-based environmental factors and vulnerability studies of the Okemesi landslide, Nigeria
    (Regional Sustainability, 2023) Adeyemi Moyosoluwa Odunayo; Olaniyi Patrick Imole; Olusola Johnson Adedeji; Akintan Oluwakemi Bolanle
    Landslide is a geological hazard typically associated with extreme events such as earthquakes, heavy rainfall, volcanic eruptions, changes in groundwater level, etc. This study was carried out in Okemesi-Ekiti (also known as Okemesi), Southwest Nigeria, with the purpose of using remote sensing and GIS technologies to analyze the environmental factors (grain size, direct shear strength resistance, rainfall data, wet density, surface, and slope) resulting in the occurrence of the Okemesi landslide. The study also aimed to conduct a vulnerability analysis in the study area to identify regions with a probability of landslide occurrence. The grain size analysis of the soil in the Okemesi landslide area showed that slope materials comprised 17.14% gravel, 59.31% sand, and 19.48% fines, thus the soil type could be classified as poorly graded gravely sand with a high possibility of landslide occurrence. The geomorphic characteristics of the study area was characterized by slopes ranging from 0.00 to 49.00 , while most slopes in the area were less than 8.00 . The slope aspect direction was mainly in south (157.51 –202.50 ), southwest (202.51 –247.50 ), west (247.51 –292.50 ), and north (0.00 –22.50 and 337.51 –360.00 ). The highlands were primarily bounded by the slope directions of north (0.00 –22.50 and 337.51 –360.00 ), northeast (22.51 –67.50 ), east (67.51 –112.51 ), and southeast (112.51 157.50 ), which indicated the potential direction of mass movement. The study area can be divided into three vulnerability zones: high, medium, and low, with the area percentages of 9.00%, 61.80%, and 29.20%, respectively. The analysis suggested that the Okemesi landslide was likely triggered by rainfall, which might have weakened the physical structure of slope materials. Understanding the causes and impacts of landslides is crucial for policy-makers to implement measures to mitigate landslide hazards, protect infrastructure, and prevent the loss of life in the landslide-prone regions.