DSpace Repository :: Browsing by Author "Osisanya, W.O."

Browsing by Author "Osisanya, W.O."

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3D TIME-LAPSE GEOPHYSICAL IMAGING OF FERTILIZER-INDUCED SOIL AND GROUNDWATER CONTAMINATION IN OGHARA, DELTA STATE, NIGERIA
(Zibeline International Publishing, 2025-07) Ozobeme, A.A.; Osisanya, W.O.; Airen, O.J.; Eyankware, O.M.; Iluobe, E.O.
Fertilizer contaminants can persist in subsurface environments, making remediation efforts costly and time consuming, particularly in areas with shallow aquifers and permeable soils. This study applied time-lapse geophysical methods to assess fertilizer-related soil and groundwater pollution in agricultural regions of Oghara, Delta State, Nigeria. Eight 2-D electrical resistivity imaging (ERI) surveys were conducted, Including 16 grid-aligned lines across the Presco lowland and upland areas which were collated to form the 3 D models, along with a control line. Data were processed using RES3DINV and ZondRes3D to produce the 3-D resistivity models. Three-dimensional slices illustrated the downward migration of contaminants over time. Analysis of time-lapse data showed maximum vertical migration rates of 216.7 cm/month and horizontal rates of 750.0 cm/month at the initial site. At the second site, rates reached 122.5 cm/month vertically and 500.0 cm/month horizontally. Taking into account local hydrological and geological conditions, the contaminant plumes are projected to reach the dry sandy layer within 0.5 to 1 year.
A COMPREHENSIVE ANALYSIS OF SOIL AND WATER CONTAMINATION NEAR AUTO MECHANIC WORKSHOPS IN WARRI AND ENVIRON SOUTH-SOUTH, NIGERIA
(Zibeline International Publishing, 2023) Aladin, A.E.; Ekewenu, E.E.; Osisanya, W.O.
The pH values of soil samples collected from the topsoil to a depth of 50cm range from 5.78 to 6.64, with an average of 6.284, indicating slightly acidic soil. Water samples near auto-mechanic workshops fall below NSDWQ and WHO standards. Soil heavy metal levels mostly meet ACV and Dutch guidelines, except for Iron (Fe), Copper (Cu), Zinc (Zn), Cadmium (Cd), and Chromium (Cr). Soil contamination analysis shows a high to extreme degree of contamination, likely from the auto-mechanic workshop. Positive correlations between metal pairs suggest a common source and transport to the soil. Principal Component Analysis (PCA) of soil samples reveals Cu, Zn, Fe, Ni, and Pb as dominant metals, while Ni-Cr shows negative correlations with others. In water samples, Cu, Cd, and Co dominate, indicating a different contamination source. Soil and water samples generally meet NSDWQ and WHO standards, but Total Dissolved Solids (TDS), Electrical Conductivity (EC), and Salinity exceed these standards. Understanding these findings is crucial for managing and mitigating contamination risks near auto-mechanic workshops
Aeromagnetic Interpretation of Basement Structures and Geometry in Parts of the Middle Benue Trough, North Central, Nigeria
(Bilingual Publishing Co., 2022-11-30) Esho, O.O.; Osisanya, W.O.; Ibitoye, T.A.; Ajibade, F.Z.; Tokunbo, S.F.
The research of an analysis of aeromagnetic data collected in the middle Benue Trough in north-central Nigeria is presented. A detailed analysis of basement structures is conducted in order to identify regions with high hydrocarbon potential that is different from those discovered by earlier researchers. Aeromagnetic data were filtered by using the Butterworth and Gaussian filters, transformed by engaging the reduction to the equator technique, and subsequently enhanced. To estimate magnetic basement depths at various places throughout the basin, the Euler deconvolution depth weighting approach was used. Eleven (11) sub-basins with depths ranging from –2000 m to –8000 m were also identified by Euler’s findings. The sub-basins trend in the NE-SW direction while the average sediment thickness is found to be more than 3 km. The extracted structural features indicate areas like Kadi Blam and Kado areas in the southeastern part and Ogoja and Obudu in the southern part of the study area as regions with high structural densities. These areas coincide with the areas delineated as the sub-basins. The cross-sections generated reveal depressions caused by the action of some tectonic activities in the area. This study identified undulating basement topography believed to be due to tectonic activities as well as five areas that are possible targets for hydrocarbon exploration.
AN IN-DEPTH STUDY OF HEAVY METALS IN SOILS AROUND SELECTED WASTE DUMPSITES IN PARTS OF SOUTHERN NIGERIA USING HEAVY METAL INDICES AND MULTIVARIATE STATISTICAL ANALYSIS
(African Journals OnLine, 2025) Osisanya, W.O.; Agbalagba, O.E.; Agho, I.O.; Eyankware, M.O.; Iduseri, O.M
A detailed study was conducted around waste dumpsite in the study area, to evaluate the levels of heavy metals in the soil. Soil samples were collected at twenty (20) different locations within waste dumpsites for the study. The heavy metals (zinc (Zn), chromium (Cr), copper (Cu), lead (Pb), cadmium (Cd), mercury (Hg), nickel (Ni), arsenic (As), and iron (Fe)) were analyzed using atomic absorption spectrometry (AAS). The resulting data was analysed using principal component analysis (PCA), Pearson correlation, and the heavy metal indices: Potential Ecological Risk (ERI), Geoaccumulation Index (Igeo), Contamination Factor (CF), and Nemerow Pollution Index (PNI). Thesoil contain the heavy metals: zinc (Zn), chromium (Cr), copper Cu, Pb, Cd, Hg, Ni, As, and Fe. Their concentrations, inorder 9.28 to 60.1 mg/kg for Zn, 4.4 to 14.39 mg/kg for Cr, 5.4 to 21.39 mg/kg for Cu, 6.07 to 17.5 mg/kg for Pb, 0.04 to 1.5 mg/kg for Cd, 0.0001 to 0.003 mg/kg for Hg, 7.28 to 20.38 mg/kg for Ni, 0.0001 to 0.003 mg/kg for As, and 1020 to 16540 mg/kg for Fe,The Igeo data indicated that all samples fell within the range of 0 to 2, implying that the sediment quality was largely unpolluted. The PNI yielded a diverse array of results within the study area, PC1 has a loading percentage of 77.8%, PC2 has a loading percentage of 44.4%, PC3 has a loading percentage of 33.3%, and PC4 has a loading percentage of 11.1%. This loading signifies the element's importance in the contribution of pollution within elements and to the soil. Further deductions from soil samples results that was compared to World Health Organization (WHO), and Department of Petroleum Resource (DPR), permissible limit suggested that all samples were below the permissible limit except for Cd, that its concentration was above WHO limit at some locations namely; DO/ 02, 03, 04, 05, 06, 08, 09, 10, 12, 13,and 18, this could be attributed to anthropogenic activities within the study area. These findings can serve as a valuable resource for those responsible for managing dumpsites, aiding in the prevention of heavy metal soil contamination.
Application of Geophysical Methods in the Determination of Pb-Zn Mineralization in Abakaliki, Parts of the Southern Benue Trough, Nigeria
(IJESKA / DergiPark, 2024-08) Ighrakpata, C.F; Osisanya, W.O.; Ajibade, F.Z
To identify Pb-Zn mineralization in the Abakaliki province, an integrated strategy was used for the objective of this study. Particularly in the Nsuba, Oputumo, Amenyi, Nsobo, and Opuitumo lodes. This investigation was conducted using two methods: the resistivity method (Dipole dipole configuration) and induced polarization (IP). The apparatus utilized for this research is the Abem Terrameter SAS 4000. There were ten (10) Dipole dipole arrays installed in the research region, with electrode spacing ranging from five to twenty meters in a NW-SE direction and a maximum spread of two hundred meters. Findings from the study suggested that mineralized zones, resistivity values ranging from 0.4 to 1354 Ω-m and chargeability values from -877 to 813 ms were found. Positive magnetic anomalies were found in areas below the ground that had unusually high chargeability and relatively low resistivity structures. This suggested that Pb-Zn minerals might be present. The mineralization, characterized as a mildly disseminated stockwork, leans towards a relatively epigenetic nature.
Application of high resolution aeromagnetic data for determination of depth to magnetic sources using source parameter imaging in Niger State, Nigeria
(Scientific Publishing House, 2025) Sunday, I. O.; Osisanya, W.O.; Saleh, A.S.; Eyankware, M.O.; Chukwusa, F.O.
Source Parameter Imaging (SPI) is a pivotal geophysical technique, particularly in aeromagnetism, for delineating subsurface geological structures through the analysis of magnetic anomalies. This study applies SPI to high-resolution aeromagnetic data over Baro and its surrounding areas in Niger State, Nigeria, to estimate the depth to magnetic sources. The research emphasizes the characterization of magnetic sources in terms of depth, geometry, dip, and susceptibility contrast. Data processing techniques, including regional field removal, residual anomaly mapping, and reduction to the magnetic equator, were employed to enhance data accuracy and interpretability. The findings reveal significant variations in sedimentary thickness, suggesting potential hydrocarbon reservoirs, particularly in the northern region, characterized by deeper basins. This study underscores the necessity of further exploration, integrating advanced seismic studies and drilling, to assess the hydrocarbon potential accurately. The SPI-derived insights provide a valuable framework for strategic hydrocarbon exploration in Nigeria's interior basins, contributing to the nation's energy security and economic growth.
Assessing Environmental Impact and Socioeconomic Consequences of Oil and Gas Spillage on Soil in Warri, Southern Nigeria
(European Centre for Research Training and Development UK, 2023) Shaibu, B.O.; Osisanya, W.O.; Amoyedo, A.A.; Akpeji, B.H.
The Niger Delta terrain is often prone to environmental degradation resulting from oil and gas spillage. This research aims to assess the environmental impact of oil and gas spillage on the soil of Warri, Southern Nigeria, by utilizing physicochemical properties, statistical analysis, and socioeconomic information to evaluate the impact of heavy metals in the study area. A total of six (6) soil samples were collected and examined with the aid of an atomic absorption spectrometer (AAS) using a procedure that adheres to World Health Organization (WHO) standards. Concentration levels of Sodium (Na), Potassium (K), Calcium (Ca), Magnesium (Mg), Exchangeable Acidity (EA), Exchangeable Cation Exchange Capacity (ECEC), Total Petroleum Hydrocarbons (TPH), Zinc (Zn), Copper (Cu), Iron (Fe), Cadmium (Cd), and Lead (Pb) were analyzed and found to range from (21.1-74.98) ppm, (23.46-105.57) ppm, (1281442) ppm, (58.80-341.60) ppm, (0.25-13.50) ppm, (11.51-14.78) ppm, (11.30-226.34) mg/kg, (98.26 122.60) mg/kg, (10.10-18.43) mg/kg, (321.86-994.04) mg/kg, (0.26-0.50) mg/kg, (0.4-1.15) mg/kg, respectively. The research revealed that the soil pH ranged from highly acidic to slightly acidic, which can negatively affect nutrient availability and plant growth. The research also highlighted the detrimental impact of oil spillage on the health, livelihood, amenities, and socioeconomic state of affected communities. Agricultural produce, crop yield, and livestock production were negatively affected due to poor soil fertility and damage to water bodies. Basic amenities were polluted, leading to abandonment and contamination of drinking water. The social environment of these communities experienced setbacks in occupation, income, and education. The findings provide valuable insights into soil characteristics and contamination levels and also show that regular soil quality monitoring and assessment are essential to detect any degradation in soil quality in the examined area.
Assessment of Aquifer-Protective Capacity of Orire Estate in Akure, Ondo State, Nigeria
(University of Port Harcourt, 2024-10-31) Olatunji-Adeniyi, O.; Ayua, K.J.; Osisanya, W.O.
The amount and thickness of clay layers and surrounding organic elements have a direct impact on how well an aquifer protects itself. Thus, the purpose of this work was to evaluate Orire Estate's ability to preserve the aquifer in Akure, Ondo State, Nigeria, using a geophysical survey that used the Vertical Electrical Sounding (VES) and Very Low Frequency (VLF) Electromagnetic Technique. Throughout the course of the survey, seven traverses of various lengths were established, and VLF-EM measurements were made every five meters along the four main profiles. Thirteen vertical electrical soundings were also performed, with electrode spacings varying from one to one hundred meters. Computer-assisted modeling and partial curve matching approaches were used in the interpretation of the data. Four subsurface geological units were identified by the analysis: topsoil, worn layer, fractured basement, and fresh basement. The topsoil layer, with a thickness ranging from 0.9 to 1.5 meters, exhibited resistivity values between 57.0 and 198.4 Ω-m. The worn layer varied in thickness from 2.6 to 17 meters, with resistivity values from 87.0 to 978.7 Ω-m. The fractured basement layer's thickness ranged from 7.8 to 23.7 meters, showing resistivity values between 311 and 3041.8 Ω-m, while the fresh basement layer demonstrated resistivity values ranging from 1423.1 to 3790.57 Ω-m with infinite thickness. The presence of zones with poor aquifer-protective capacity throughout the study area indicates a heightened vulnerability to contamination from leachates and other pollutants. The subsurface conditions suggest an abundance of unconsolidated sand with limited clay, which prolongs the residence time of percolating pollutants and diminishes the necessary impediment to fluid movement for effective filtration.
Assessment of heavy metal pollution on groundwater quality in the Niger Delta Region of Nigeria
(Springer Nature, 2023-11-21) Eyankware, M.O.; Akakuru, O.C.; Osisanya, W.O.; Umayah, S.O.; Ukor, K.P.
Heavy metal (HM) pollution in groundwater poses a significant environmental threat to the Niger Delta region of Nigeria, principally because of the activities of oil companies within the locality. The current study considered it necessary to measure the HM level in the groundwater of this location. 18 groundwater samples were collected and tested for physical parameters (pH, EC, TDS), as well as heavy metals (Cr, Cu, Zn, Co, Fe, Mn, B, Ni, and Cd). Results from the principal component analysis (PCA) analysis reveal the influence of heavy metals on groundwater chemistry. The correlation matrix results showed that there exists a weak and positive correlation among elements, revealing that heavy metals in water with a low pH tend to be more toxic, as they become more soluble and bioavailable. HM pollution assessment results revealed that the values were considered low, with values ranging from 0 to 0.33 with an average value of 0.07. Metal pollution index (MPI) results showed that the groundwater sample was very pure. Nemerow Pollution Index (PNI) results revealed that the groundwater samples were heavily polluted. Results from the modified degree of contamination (MCd), showed that the majority of the samples had a very low degree of contamination. The pollution load index (PLI) results indicated that the entire samples were polluted. Quantification of contamination (QoC) results showed a geogenic impact on the samples. Based on the findings, monitoring groundwater quality and using appropriate treatment technologies to purify the water before consumption are recommended
Critical Evaluation of Crude Oil and Sediments from Selected Areas of the Niger Delta.
(International Journal of Earth Sciences Knowledge and Applications, 2026-08-03) Onoriode, D.A.; Ibe, K. A.; Osisanya, W.O.; Saleh, A.S.
Understanding the occurrence, composition, and distribution of aliphatic hydrocarbons (AHCs) is crucial for assessing anthropogenic contributions and identifying the sources of AHCs in the environment. Therefore, this study focused on analyzing the concentrations, distribution patterns, and compositional characteristics of AHCs present in crude oil and sediments from the Udu, Ethiope East, and Ughelli North Local Government Areas. A total of nine crude oil samples and ten sediment samples were gathered from the research area. The concentrations of AHCs in these samples were quantified using gas chromatography with a Flame Ionization Detector (GC-FID) following extraction with a hexane/dichloromethane mixture and subsequent purification using a silica gel/alumina packed column. Analysis of the molecular indices indicated that the AHCs present in the sediments originated from marine biogenic, terrestrial biogenic, and petrogenic sources, whereas the hydrocarbons in the crude oil were derived exclusively from marine and terrestrial biogenic sources.
DELINEATION OF GROUNDWATER POTENTIAL USING ELECTRICAL RESISTIVITY IMAGING TECHNIQUES AT IBULE AKURE, SOUTHWESTERN NIGERIA
(Zibeline International Publishing, 2024) Adeniyi, A.E.; Osisanya, W.O.; Eyankware, M.O.
Population growth and heightened water demand in the study area, exacerbated by insufficient surface and groundwater resources, lead to severe water shortages, particularly during the dry season. In response, our study in Atibioke Street, Aule Road, Ibulesoro, Akure, Ondo State, employed Horizontal Profiling (HP) and Vertical Electrical Sounding (VES) with electrical resistivity methods. Conducted across three traverses at 5m intervals, with probing levels from 1 to 5, the Combined HP and VES generated 2-D pseudosections, highlighting features and conducive layers for groundwater accumulation. Using Schlumberger configuration with electrode spacings from 1 to 100 m, three Vertical Electrical Soundings classified subsurface layers into Topsoil, Weathered Layer, and Fresh Bedrock within the basement complex terrain. The study emphasized the significance of electrical resistivity in assessing groundwater potential, with recommendations highlighting the unsuitability of VES 1 and VES 2 for exploitation, while VES 3 exhibited favorable conditions. Overall groundwater potential was rated as medium, emphasizing the need for alternative water supply solutions. VES 3 was recommended for well drilling based on promising characteristics, concluding with a suggestion to use these findings as a reference for future geophysical investigations.
Depiction of Aquifer Potential and Vulnerability Mapping: A Case Study of Delta North, Southern Part of Nigeria, Using Geophysical Approach
(Discovery Scientific Society, 2025) Eyankware, M.O.; Osisanya, W.O.; Akakuru, O.C.; Odesa, G.E.; Okanigbuan, P.N.; Ukor, K.P.; Oghenevovwero, E.E.; Chukwusa, F.O.
In order to identify the aquifers, characterize their geometric properties, and determine their susceptibility to contamination by surface contaminants, a detailed hydrogeophysical investigation of the aquifers of the study area was conducted. The study area was subjected to fifteen (15) vertical electrical soundings (VES) with a Schlumberger array configuration with a maximum electrode separation of 200 m. Curve matching methods and iterative computer modeling were combined to process the VES data. Parameters estimated are aquifer thickness, longitudinal conductance (S), transverse unit resistance (Tr), average longitudinal resistance (ρL), aquifer conductivity (ῼ−1), hydraulic conductivity (K), and transmissivity (T), and their corresponding estimated values, which vary across the study area, range from 1.63 to 103.83 m, 0.02 to 0.05, 0 to 122169.9 ohms, 0 to 3406.4, 0.000037 to 0.001126, 0.0538 to1.13x1023m2/day, 0 to 1.85x1023m2/day, respectively. Deductions from S. revealed that the study area is prone to contamination from the study. Further findings from groundwater modeling, hydraulic conductivity, and transmissivity suggested that the southwestern part of the study area showed more groundwater prospects when compared to other parts of the study area. Within the study, it was observed that curve Q is the most dominant curve within the study area.
DIGITISATIZATION OF WELL CORELLATION AND PETROPHYSICAL ANALYSIS OF “OKPELLA” FIELD, NIGER DELTA
(Zibeline International Publishing, 2024) Oyanameh, O.E.; Ayuk, M.A.; Fagbemigun, T.S.; Osisanya, W.O.; Onoghoro, B.B.
The oil and gas industry is continuously evolving, with a growing emphasis on digital transformation to enhance exploration and production processes. This paper presents a detailed study on the digitization of well correlation and petrophysical analysis in the "Okpella" Field, located in the prolific Niger Delta basin. The Okpella Field represents a significant hydrocarbon reservoir with complex geological and petrophysical characteristics, making it an ideal case study for the implementation of advanced digitization techniques. This research presents the results of log suit analysis from the “OKPELLA” field, Niger Delta. The study aimed at locating the hydrocarbon potential of lithological units encountered during the drilling of the “OKPELLA” field. The primary objectives of this research are to improve well correlation accuracy, optimize reservoir characterization, and enhance reservoir management in the Okpella Field. To achieve the general objective, suites of wire-line logs from the “OKPELLA” field were used for the research. Based on wire-line logs, two types of lithology were identified, which include sand and shale. Five sand bodies are marked as reservoirs, and they are denoted as R1, R2, R3, R4, and R5. The sand bodies were identified with their tops and bases at a depth interval of 4880 m to 6050 m. Computed petrophysical parameters for the five reservoir zones gave an average total porosity of 8% to 28%, with low permeability in the range of 0.56 D to 0.95 D. The high permeability indicates that the reservoir sand bodies are permeable. The fluid type defined in the reservoir zones is hydrocarbon, with a high saturation greater than 75%, which indicates that the proportion of void space occupied by hydrocarbon is high, consequently low water saturation and production. Summarily, the good porosity, high permeability, and low water saturation obtained via petrophysical analysis of the “OKPELLA” field indicate that the quality of hydrocarbon within the five (5) reservoirs found in the field of study is prolific and of commercial use.
ENHANCING THE ENGINEERING PROPERTIES OF LATERITIC SOILS USING ANTHILLS, SPECIFICALLY MOLD SOILS, IN CERTAIN PARTS OF THE BENIN METROPOLITAN CITY IN SOUTHERN NIGERIA
(Zibeline International Publishing, 2023) Andre-Obayanju, O.; Ese, A.A.; Osisanya, W.O.
The study was carried out in Ovia North-East local government area of Edo state. The study area is located between latitudes of 6°24'16.116''N and longitudes of 5°37'26.205″E to 5°36'16.8''E in Ovia North-East local government area. A total of three (3) soil samples were collected from an Anthill (Mold soil) mix with Lateritic soil at 0%, 3% and 6%. The following geotechnical analyses (the Particle size analysis, Specific Gravity, Atterberg Limits, Compaction Test and Triaxial Tests) was carried on the Mold soil samples mixed with lateritic soil to evaluate their suitability for road construction. The analyses revealed that approximately 10% of the soil composition consists of fine sand grains, while the majority, accounting for 90%, is characterized as medium to coarse grained. The particle size distribution analysis of the Mold soil indicated that the percentage of fines is below 35%, classifying it as coarse-grained according to the American Association of State and Highway Transport Officials (AASHTO). The Mold soil exhibited weight retention of 47.26 grams. The Specific Gravity ranged from 2.34 to 2.51, Liquid Limit varied from 51.80% to 63.05%, Plastic Limit ranged from 26.70% to 29.39%, Plasticity Index ranged from 25.10% to 33.52%, and Shear strength spanned from 26.748 to 50.066 kN/m². The results of the Compaction Test indicated that the Maximum Dry Density (MDD) ranged from 1.54 to 1.61 g/cm³, and the Optimum Moisture Content ranged from 14.45% to 13.93% for Mold soils mixed with lateritic soil at 0%, 3%, and 6%, respectively. The study results demonstrate that the incorporation of Mold soil enhances the geotechnical properties of the soil, while the Anthill proves to be a beneficial additive for improving lateritic soil in road construction. Furthermore, the Mold soil sample, when mixed with lateritic soil, meets the specifications set by the Federal Ministry of Works and Housing, specifically maintaining a percentage of ≤ 18% for sub-base and base materials. This finding underscores the suitability of the soil for road construction purposes.
Evaluation of Residual Geo-mechanical Characteristics of Rocks from Akure, Ado Ekiti and Ikare-Akoko Quarries in Southwest Nigeria
(University of Port Harcourt, 2025) Oluwadero, T.A.; Osisanya, W.O.; Ajibade, F.Z.
The objective of this paper is to evaluate the Residual Geo-mechanical Characteristics of Rocks from Akure, Ado-Ekiti and Ikare-Akoko Quarries in Southwest Nigeria using appropriate standard techniques. Data obtained show that residual ultimate compressive strength (UCS) values under in-situ circumstances were, in order, 70.56 MPa, 72.9 MPa, and 76.27 MPa. It was shown that when the concentrations of acid and base in the immersion solution increased, the samples' UCS decreased. Compared to samples with coarser grains, those with finer grains (as determined by the microstructure analysis) retained a comparatively higher UCS value even after being submerged in an acidic and alkaline medium. The samples that were soaked in 0.75M, 1.5M, and 3.0M of acid and base showed varying degrees of deterioration during the second wetting cycle in the water medium, despite not being detected to be damaged during the first cycle. However, the durability was found to decrease much more when the medium was turned acidic and alkaline.
Geochemical Assessment of Bottom Sediments of Water Bodies at Crude Oil Exploration Station in Delta State, Nigeria.
(Discovery Nature, 2025) Abolodje, O.D.; Ibe, K.A.; Osisanya, W.O.; Ibitoye, T.A.; Saleh, A.S.
Understanding the occurrence, composition, and distribution patterns of aliphatic hydrocarbons (AHCs) are crucial signals for identifying the anthropogenic contributions and sources of AHCs present in the environment. Therefore, this study focused on analyzing the concentrations, distribution pattern, compositional patterns, and sources of AHCs found in crude oil and sediments collected from the Udu, Ethiope East, and Ughelli North Local Government Areas. A total of nine (09) crude oil samples and ten (10) sediment samples were obtained from the designated study area. The analysis of AHC concentrations in these identification was performed by gas chromatography with Flame Ionization Detector (GC-FID) using hexane/dichloromethane mixture and further purification in a column filled with silica gel and alumina. The AHC in the crude oil samples were observed to be between 450 and 43657 mg/kg, with an average of 2859.11+7884.68mg/kg. The sediment samples on the other hand contained concentrations of AHC that varied between 10.8 and 470mg/kg with a mean concentration of 102.74 +2.85 mg/kg. The UNEP guideline limit of AHCs in sediments is 10 mg/kg, yet they were greater than those. The AHCs of the crude in the Ethiope East Local Government Area were detected to be 3071 +53.3mg/kg. Udu Local Government Area on the other hand reported concentrations of 14999 +/-314.3 and 155027 +/-291.7mg/kg. AHCs of the Ughelli North Local Government Area were 1149±69.7, 21686±3352.8, 14099±147.7, 450±17.3, 1114±19.6, and 43657±2185.3 mg/kg. Regarding sediment, the AHCs recorded were 12.7±0.3 and 18.8±0.6 mg/kg for Ethiope East Local Government Area, while Udu Local Government Area presents recorded values of 17. The results of the ANOVA reveal a significant difference (p<0.05) in the levels of AHCs found in both crude oil and sediment samples. Furthermore, the regression analysis indicates a minimal or nonexistent correlation between AHC concentrations in crude oil and those in sediment. Notably, the predominant hydrocarbons (MH) identified in the samples of crude oil and sediment were characterized by even carbon numbers, including C8, C16, C18, C32, C34, C36, and C38.
Geochemical implications of hydrocarbon exploitation on the soil around the crude oil‑producing area of Uzere, Niger Delta region, Nigeria
(Springer, 2025-11) Ibitoye, A.T.; Osisanya, W.O.; Imasuen, I.O.
The crude oil sector in Nigeria continues to be a significant source of income and foreign currency. H0wever, operations related to oil exploration and production have the potential to seriously alter the environment, having an impact on ecosystems, water bodies, and human life. In many cases, pollution indices are viewed as a useful instrument for thoroughly evaluating contamination levels. Additionally, they may have a significant impact when evaluating soil quality and the forecast of long-term ecosystem viability, in the case of farmlands in particular. Atomic absorption spectrometry (AAS) was used to examine the heavy metal contents. Potential ecological risk index, geoaccumulation index, Nemerow pollution, pollution load index, contamination index (CI), and metal pollution index were the seven indicators employed in the study. The concentration of heavy metals such as manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), chromium (Cr), and arsenic (As) ranges from 11.9 to 184.1, 920 to 8870, 1.1 to 9.9, 9.7 to 60.4, 0.001 to 0.001, 2.4 to 34.7, 2.2 to 11.5, and 0.001 to 0.001 mg/kg, respectively. The correlation matrix showed that there were positive correlations between Mn and Ni, Fe and Cu, Zn, Pb, Cr, Cu and Cr, Zn and Pb, Cr, and Pb and Cr, while a negative correlation exists between Cu and Ar. PCA showed that 75% of the samples in PC1 have loadings; in PC2, 50% of the parameters have loadings; in PC3, 25% of the parameters have loadings; and in PC4, 12.5% of the entire parameter has loadings. Findings from the aforementioned indices revealed that the analyzed soil samples are polluted.
GEOTECHNICAL ASSESSMENT AND FOUNDATION DESIGN RECOMMENDATIONS FOR THE PROPOSED ENGINEERING STRUCTURE: A CASE STUDY OF WARRI- SOUTH LOCAL GOVERNMENT AREA, DELTA STATE
(Zibeline International Publishing, 2024) Aladin, A.E; Osisanya, W.O.; Komolafe, N.P; Korode, A.I
The research offers an evaluation of the geotechnical index properties of the sub-soil at the proposed building site in Agbassa Community, Warri South Local Government Area of Delta State, Nigeria. Four boreholes were drilled at the site, each reaching a depth of 10.0 meters. The study area, which spans 100m x 100m, was thoroughly investigated through both field studies and laboratory testing. The results reveal that the sub-soil consists of 3 meters of high plasticity clay with high moisture content, overlain by 4 to 5 meters of silty sand that transitions to fine to coarse sand down to a depth of 10 meters. The sand's textural composition indicates a coefficient of uniformity ranging from 2.01 to 2.04. According to the Unified Soil Classification System, the sand is classified as SM (Silty Sand). The grain size, according to British Standard Sieve Sizes, ranges from 0.06mm to 10mm, showing that the sand is uniformly graded. Further laboratory tests classified the soil as Silty Sand (SM) and the clay as CH under the Unified Soil Classification System. Analysis of geotechnical parameters such as Kv, Cv, Mv, and pressure-depth relationships indicates that the sub-soil is highly compressible with low porosity. The ultimate bearing capacity of the soil ranges from 257.9kN/m² to 341.58 kN/m², with allowable bearing pressures between 85.97kN/m² and 113.86kN/m². Based on these findings, it is recommended to use a long strip foundation for the proposed structure, as it is both adequate and economical. The scope of the work included drilling four boreholes, collecting samples, and assessing the soil's suitability for the intended construction project.
GROUNDWATER FLOW DIRECTION EVALUATION FOR FLOOD AND CONTAMINATION CONTROL IN OSUBI, SOUTHERN NIGERIA
(Zibeline International Publishing, 2023) Onifade, Y.S.; Osisanya, W.O.
The determination of groundwater flow direction is essential in flood and groundwater contamination control. This study aimed at determining the groundwater flow direction in the study area to infer possible areas of further spread of contaminants and identify areas that might be prone to flooding shortly. Fifty (50) hand-dug wells were sampled with the aid of a long tape (200/60m) and a global positioning system (GPS) to determine their hydraulic heads, while topography and groundwater flow direction maps of the study area were generated using surfer 13 and groundwater modeling software, respectively. The result revealed that the hydraulic heads and static water level (SWL) values range from 0.63-27.15 m and 1.15–4.88 m, respectively, while the elevation values range from 5–30 m. The study area is characterized by undulating and relatively flat terrain in different parts of the area, while the groundwater flow direction depicts a nonuniform directional flow of groundwater in the study area. This suggests that the groundwater contamination discovered in the area might soon spread to contaminate their nearby environs if not promptly and urgently controlled. It is hereby recommended that every anthropogenic activity, such as abattoirs, mechanic workshops, dumpsites, etc., that can increase the rate of groundwater contamination in the study area be restricted to the north-eastern, eastern, and southeastern parts due to their low hydraulic heads.
GROUNDWATER FLOW DIRECTION EVALUATION FOR FLOOD AND CONTAMINATION CONTROL IN OSUBI, SOUTHERN NIGERIA
(Big Data in Water Resources Engineering, 2023) Onifade, Y.S.; Osisanya, W.O.
The determination of groundwater flow direction is essential in flood and groundwater contamination control. This study aimed at determining the groundwater flow direction in the study area to infer possible areas of further spread of contaminants and identify areas that might be prone to flooding shortly. Fifty (50) hand-dug wells were sampled with the aid of a long tape (200/60m) and a global positioning system (GPS) to determine their hydraulic heads, while topography and groundwater flow direction maps of the study area were generated using surfer 13 and groundwater modeling software, respectively. The result revealed that the hydraulic heads and static water level (SWL) values range from 0.63-27.15 m and 1.15–4.88 m, respectively, while the elevation values range from 5–30 m. The study area is characterized by undulating and relatively flat terrain in different parts of the area, while the groundwater flow direction depicts a nonuniform directional flow of groundwater in the study area. This suggests that the groundwater contamination discovered in the area might soon spread to contaminate their nearby environs if not promptly and urgently controlled. It is hereby recommended that every anthropogenic activity, such as abattoirs, mechanic workshops, dumpsites, etc., that can increase the rate of groundwater contamination in the study area be restricted to the north-eastern, eastern, and southeastern parts due to their low hydraulic heads.

Browsing by Author "Osisanya, W.O."

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