The carbon sequestration capacity and climate change mitigation potentials of mangrove sediments ... more The carbon sequestration capacity and climate change mitigation potentials of mangrove sediments in eastern Niger Delta were investigated. The aim was to determine the carbon stock in the sediments as a measure of carbon sequestration. A total of 312 sediment samples were obtained from 24 sampling 100 cm deep borings at seven locations using an open-cylindrical gouge auger of 100-cm length and 5-cm diameter. The procedures for field sampling, laboratory analysis and result presentation followed protocols for forest carbon measurement, monitoring and reporting. The lithology at the site, which is a major control on the distribution of organic carbon, included peat, peaty clay, and clayey peat with pockets of sands. Sediment bulk density (SBD), organic carbon concentration (%C), were used to estimate the organic carbon stock, carbon dioxide equivalent (CO2e), and to calculate carbon sequestration rate (CSR) and sequestration potential (CSP). Mean values of SBD were 1.30 g/cm3) and 12.48 %) respectively. Similarly, carbon averaged 39.80 Mg ha–1. The total carbon stock of the study area was estimated at 199,617.36 ±55.64 Mg C, equivalent to 732,595.71 ± 55.64 Mg CO2. CSR was estimated at 4.54 g C cm–2 yr–1 while CSP of mangrove sediments was estimated at 21.56 Mg C yr–1. The result showed that 732,595.71 ± 55.64 Mg of carbon dioxide could either be removed or released to the atmosphere by the mangrove forest of Niger Delta through forest management practices and/or degradation. The study reinforces the need for the protection of mangroves against all anthropogenic-related degradation to improve carbon sequestration potential and achieve target in line with Sustainable
Development Goal 13.
Geochemical analysis of borehole soil samples for Total Petroleum Hydrocarbon (TPH), geoelectrica... more Geochemical analysis of borehole soil samples for Total Petroleum Hydrocarbon (TPH), geoelectrical imaging and geotechnical sieve analysis were used to assess the intensity and extent of hydrocarbon contamination at an ancient oil spill site near Ejama-Ebubu community in Eleme, near Port Harcourt. The subsurface sequence is generally composed of sandy clay/clayey sand to depth of over 10 m. The clayey sand consists of 24-37% fines and 63-76% sand. Soils Total Petroleum Hydrocarbon (TPH) concentrations generally decrease from a maximum of 6428 ppm at 1 m at the time of investigation to a minimum of 1508 ppm at 5 m depth within the impacted zone. These values are much higher than the Department of Petroleum Resources (DPR) background value of 50 ppm for TPH in soils of the Niger Delta, thereby establishing high level of contamination.
In this study, the chemical composition of water and soils contiguous to two abandoned coal mines... more In this study, the chemical composition of water and soils contiguous to two abandoned coal mines in southeastern Nigeria, was assessed to evaluate the impact of water flow from the mines ponds on the geoenvironment and potential for acid mine drainage (AMD). Parameters including the pH, anions and cations, and the heavy metals were measured. These were used to evaluate contamination/pollution using hybrid factors including Pollution Load Index, factors, enrichment factors, pollution load index and index of geoaccumulation. The pH range of 3.4 to 5.9 classified the water as weakly to strongly acidic, typical of AMD. The SO42– ion, which indicates pollution by mine waters, showed moderate to high concentrations. Iron, zinc lead and copper were the most abundant heavy metals. Pollution Load Index values were greater than unity which show progressive deterioration in water and sediment quality. The Enrichment Factor values of up to 1 indicated enrichment through lithogenic and anthropo...
Constant rate, single well pumping tests were conducted using boreholes located in four communiti... more Constant rate, single well pumping tests were conducted using boreholes located in four communities in the study area with the aim of determining the aquifer hydraulic properties using the Cooper Jacob method. Fractured shales yielded groundwater into the wells whose depths ranged from 26 to 35m while the static water level varied from 5.81 to 8.76 m. During the test, the maximum drawdown observed was between 11.89 and 21.34 m. The hydraulic conductivity values fell between 6.1 x 10-2 and 6.45 x 10-1 m3/day while transmissivity ranged from 0.49 to 4.52m2/day and specific capacity from 18.41 to 117.92 m2/day. The specific yield varied between 78.62 and 87.26 m3/day. Classification based on transmissivity values shows a very low to low yield aquifer. This correlates well with the litholog which showed fractured shales as the groundwater bearing unit supplying water into the wells. Good correlation (correlation coefficient, R2) of 0.8753 was obtained between transmissivity and specific capacity. The hydraulic coefficient and transmissivity indicate that for sustainable aquifer productivity, boreholes in the area should be installed with low horse power pump size for domestic use. Key words: Pumping test, Aquifer, Hydraulic conductivity, Transmissivity, Specific capacity
International journal of engineering science technologies, Jul 20, 2022
The Geotechnical properties of soils in Uyo town were analyzed to determine the bearing capacity ... more The Geotechnical properties of soils in Uyo town were analyzed to determine the bearing capacity and generate maps for shallow and deep foundation designs. Eleven geotechnical boreholes were drilled to a maximum depth of 20 meters each across Uyo town. Standard penetration tests and cone penetration tests were also carried out on the field. Soil samples were retrieved during the field investigation for various laboratory tests including liquid limits, plastic limit, bulk density, shear strength and particle size distribution. The general soil profile consists of silty clays, sandy clays, and sand from top to bottom. The silty clays are firm, low compressibility clays with liquid limit and plastic limit percentages between 32%-45% and 10%-45% respectively, cohesion averages of 4˚ to 12˚ and angles of internal friction between 48KN/m2-68KN/m2. Ultimate bearing capacities of this horizon range from 354.6kN/m2 to 866.7kN/m2. The sandy clays are also firm, low to intermediate plasticity clays with liquid limit and plasticity indexes of 29%-42% and 9%-15% respectively. Their cohesion averages range between 50KN/m2-65KN/m2 and angles of internal friction between 6˚-12˚. The ultimate bearing capacities of this clay range from 482.5KN/m2 to 906.2KN/m2. The sand is a poorly graded, medium dense sand with standard penetration test N-values between 8 to 23. Pile bearing capacities of the sand gave ultimate and allowable bearing capacities between 10262.9KN-11510.2KN and 4105.2KN-4604.1KN respectively. The sand substratum is a suitable termination depth for piles.
International Journal of Engineering Science Technologies
The Geotechnical properties of soils in Uyo town were analysed to determine the bearing capacity ... more The Geotechnical properties of soils in Uyo town were analysed to determine the bearing capacity and develop maps for shallow and deep foundation designs, which may serve as field models, for the planning of site investigation programmes for foundation purposes. Eleven boreholes were drilled to a maximum depth of 20 meters each across Uyo town. Standard penetration tests and cone penetration tests were also carried out on the field. Soil samples were retrieved during the field investigation for various laboratory tests including liquid limits, plastic limit, bulk density, shear strength and particle size distribution. The general soil profile consists of silty clays, sandy clays and sand from top to bottom. The silty clays are firm, low compressibility clays with liquid limit and plastic limit percentages between 32%-45% and 10%-45% respectively, cohesion averages of 4˚ to 12˚ and angles of internal friction between 48KN/m2-68KN/m2. Ultimate bearing capacities of this horizon range ...
Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analyse... more Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analysed to determine their swelling and slaking characteristics and effect on pavement construction and stability of slopes. Engineering problems reported in areas underlain by the soils include pavement failure and landslides. Results show that for the Ekenkpon shale, Liquid Limit, Plasticity Index and free swell averaged 45%, 14%, and 23% respectively compared to values for Nkporo shale which were 45%, 14%, and 17% respectively. Montmorrilonite, illite and kaolinite are major mineral components of the soils. The undrained cohesion values of 47 to 49kN/m and angle of internal friction between 3 and 4 suggest low shear strength. The slake durability index of Ekenkpon shale was 41% compared to 8% for Nkporo shale. The index properties, mineralogy and the slake durability index imply that all the shales are soil-like, have moderate expansivity and are of low shear strength. They are susceptible ...
Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria... more Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2. Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to...
Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analyse... more Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analysed to determine their swelling and slaking characteristics and effect on pavement construction and stability of slopes. Engineering problems reported in areas underlain by the soils include pavement failure and landslides. Results show that for the Ekenkpon shale, Liquid Limit, Plasticity Index and free swell averaged 45%, 14%, and 23% respectively compared to values for Nkporo shale which were 45%, 14%, and 17% respectively. Montmorrilonite, illite and kaolinite are major mineral components of the soils. The undrained cohesion values of 47 to 49kN/m 2 and angle of internal friction between 3 and 4 o suggest low shear strength. The slake durability index of Ekenkpon shale was 41% compared to 8% for Nkporo shale. The index properties, mineralogy and the slake durability index imply that all the shales are soil-like, have moderate expansivity and are of low shear strength. They are suscepti...
A natural gradient tracer test with sodium chloride as the injectate was conducted using one inje... more A natural gradient tracer test with sodium chloride as the injectate was conducted using one injection well and eleven observation wells in an oil-contaminated site in the study area. The aim was to characterize the site and to determine migration rates of the contaminants to provide information on their fate in groundwater resources in the area. The migration of the tracer was constantly monitored by sampling all the observation wells spaced 5 m from each other at 15-30 min intervals for a period of 6 days. The test soil layer is a clayey silty sand consisting of 50 % sand, 30 % silt and 20 % clay. The average static water level at the site is about 2.5 m. Gas chromatography fingerprinting showed that kerosene and diesel are the dominant fractions within the soil matrix. The arrival times of the breakthrough moments of the migrating tracer plume from two observation piezometers situated 2.0 and 7.22 m away from the injection well showed that the mean velocity in the longitudinal direction in the aquifer is 1.403 9 10 -3 ms -1 (121 m/day). The longitudinal and transverse dispersion coefficients of 2.45 9 10 -3 m 2 s -1 and 2.3 9 10 -3 m 2 s -1 were used to obtain longitudinal and transverse dispersivities of 1.78 and 1.64 m, respectively. High hydraulic conductivity denoted by the high migration rate of the tracer implies that contaminant at the site will migrate through the aquifer with relative ease. However, the significant clay fraction within the soil provides the medium for adsorption and partitioning of contaminants to the soil.
In this work, the properties of some basement rocks in Bansara area in the Nigerian sector of the... more In this work, the properties of some basement rocks in Bansara area in the Nigerian sector of the Bamenda massif which determine their suitability for the production of aggregate for construction works were assessed to evaluate their performance as pavement materials. ...
This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site... more This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site impacted by an unquantified volume of petroleum hydrocarbon where depth to groundwater level may be less than one metre during peak rainy season. Pre-remediation concentration of Total Petroleum Hydrocarbon in soils was 30,000mg/kg to 160,000mg/kg while post remediation values were below the intervention values of 5,000mg/kg, but still higher than the target values of 50mg/kg specified for the Petroleum Industry in Nigeria. Similarly, BTEX levels reduced from 5mg/kg to less than 1mg/kg in soil and from 400µg/l to ˂3µg/l in groundwater. Post-remediation Primary Aromatic Hydrocarbon concentrations reduced from 700mg/kg to 5mg/kg in soil and from 10µg/l to ˂3µg/l in groundwater. Seasonal fluctuations of the groundwater level imprinted a hydrocarbon smear of about 3-6m within the silty and sandy soil profile. The presence of the post-remediation residual contaminants at these concentrations...
This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site... more This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site impacted by an unquantified volume of petroleum hydrocarbon where depth to groundwater level may be less than one metre during peak rainy season. Pre-remediation concentration of Total Petroleum Hydrocarbon in soils was 30,000mg/kg to 160,000mg/kg while post remediation values were below the intervention values of 5,000mg/kg, but still higher than the target values of 50mg/kg specified for the Petroleum Industry in Nigeria. Similarly, BTEX levels reduced from 5mg/kg to less than 1mg/kg in soil and from 400µg/l to ˂3µg/l in groundwater. Post-remediation Primary Aromatic Hydrocarbon concentrations reduced from 700mg/kg to 5mg/kg in soil and from 10µg/l to ˂3µg/l in groundwater. Seasonal fluctuations of the groundwater level imprinted a hydrocarbon smear of about 3-6m within the silty and sandy soil profile. The presence of the post-remediation residual contaminants at these concen...
In this work, the propert ies of some basement rocks in Bansara area in the Nigerian sector of th... more In this work, the propert ies of some basement rocks in Bansara area in the Nigerian sector of the Bamenda massif wh ich determine their suitability for the p roduction of aggregate for construction works were assessed to evaluate their performance as pavement materials. The rock materials evaluated were from Biotite-Granite, Gran ite-Gneiss, Schist and Greenstone rocks. The Biotite-Gran ite gave Aggregate Abrasion Value (AAV) of 22.0%, Aggregate Crushing Value (A CV) of 23.3%, Aggregate Impact Value (AIV) of 18.5% and water absorption of 0.54% while Granite-Gneiss has 27.0%, 26.1%, 22.8% and 0.73% and the Greenstone has 45.2%, 55.9%, 49.6% and 3.90% respectively. Although the Biotite-Granite and Granite-Gneiss possess the necessary criteria for use as construction aggregates, the Biotite- Gran ite is of better quality because of its exceptionally high strength value and low water absorption. The high resistance of Biotite-Granite and its low water absorption could be attributed to ...
Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria... more Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2. Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to A-2-4 subgroups of the AASHO classification. The overall implication of these composite engineering properties is that the non-lateritic soils rate as poor to fair subgrade materials.
The status of oil contaminated sites in the Niger Delta has been poorly studied; flow dynamics an... more The status of oil contaminated sites in the Niger Delta has been poorly studied; flow dynamics and fate of these hydrocarbon contaminants once released into the surface are unknown. The severity of this pollution problem depends upon the rate of migration of these organic and inorganic compounds through porous media. In this work, a model of contaminant migration patterns of non aqueous phase liquids (NAPLs) in the Niger Delta region using a small scale sodium chloride field test was designed to predict the fate and transport of contaminants. The migration pattern of the tracer was studied using the surfer software. The combination of vector grid map and the contour map layers enhanced the modelling of the magnitude and direction of groundwater flow, solute/contaminant migration. The models demonstrated that longitudinal advection was more pronounced than the transverse advection. The concentration peaks decreased progressively away from the injection well and revealed the attenuati...
The carbon sequestration capacity and climate change mitigation potentials of mangrove sediments ... more The carbon sequestration capacity and climate change mitigation potentials of mangrove sediments in eastern Niger Delta were investigated. The aim was to determine the carbon stock in the sediments as a measure of carbon sequestration. A total of 312 sediment samples were obtained from 24 sampling 100 cm deep borings at seven locations using an open-cylindrical gouge auger of 100-cm length and 5-cm diameter. The procedures for field sampling, laboratory analysis and result presentation followed protocols for forest carbon measurement, monitoring and reporting. The lithology at the site, which is a major control on the distribution of organic carbon, included peat, peaty clay, and clayey peat with pockets of sands. Sediment bulk density (SBD), organic carbon concentration (%C), were used to estimate the organic carbon stock, carbon dioxide equivalent (CO2e), and to calculate carbon sequestration rate (CSR) and sequestration potential (CSP). Mean values of SBD were 1.30 g/cm3) and 12.48 %) respectively. Similarly, carbon averaged 39.80 Mg ha–1. The total carbon stock of the study area was estimated at 199,617.36 ±55.64 Mg C, equivalent to 732,595.71 ± 55.64 Mg CO2. CSR was estimated at 4.54 g C cm–2 yr–1 while CSP of mangrove sediments was estimated at 21.56 Mg C yr–1. The result showed that 732,595.71 ± 55.64 Mg of carbon dioxide could either be removed or released to the atmosphere by the mangrove forest of Niger Delta through forest management practices and/or degradation. The study reinforces the need for the protection of mangroves against all anthropogenic-related degradation to improve carbon sequestration potential and achieve target in line with Sustainable
Development Goal 13.
Geochemical analysis of borehole soil samples for Total Petroleum Hydrocarbon (TPH), geoelectrica... more Geochemical analysis of borehole soil samples for Total Petroleum Hydrocarbon (TPH), geoelectrical imaging and geotechnical sieve analysis were used to assess the intensity and extent of hydrocarbon contamination at an ancient oil spill site near Ejama-Ebubu community in Eleme, near Port Harcourt. The subsurface sequence is generally composed of sandy clay/clayey sand to depth of over 10 m. The clayey sand consists of 24-37% fines and 63-76% sand. Soils Total Petroleum Hydrocarbon (TPH) concentrations generally decrease from a maximum of 6428 ppm at 1 m at the time of investigation to a minimum of 1508 ppm at 5 m depth within the impacted zone. These values are much higher than the Department of Petroleum Resources (DPR) background value of 50 ppm for TPH in soils of the Niger Delta, thereby establishing high level of contamination.
In this study, the chemical composition of water and soils contiguous to two abandoned coal mines... more In this study, the chemical composition of water and soils contiguous to two abandoned coal mines in southeastern Nigeria, was assessed to evaluate the impact of water flow from the mines ponds on the geoenvironment and potential for acid mine drainage (AMD). Parameters including the pH, anions and cations, and the heavy metals were measured. These were used to evaluate contamination/pollution using hybrid factors including Pollution Load Index, factors, enrichment factors, pollution load index and index of geoaccumulation. The pH range of 3.4 to 5.9 classified the water as weakly to strongly acidic, typical of AMD. The SO42– ion, which indicates pollution by mine waters, showed moderate to high concentrations. Iron, zinc lead and copper were the most abundant heavy metals. Pollution Load Index values were greater than unity which show progressive deterioration in water and sediment quality. The Enrichment Factor values of up to 1 indicated enrichment through lithogenic and anthropo...
Constant rate, single well pumping tests were conducted using boreholes located in four communiti... more Constant rate, single well pumping tests were conducted using boreholes located in four communities in the study area with the aim of determining the aquifer hydraulic properties using the Cooper Jacob method. Fractured shales yielded groundwater into the wells whose depths ranged from 26 to 35m while the static water level varied from 5.81 to 8.76 m. During the test, the maximum drawdown observed was between 11.89 and 21.34 m. The hydraulic conductivity values fell between 6.1 x 10-2 and 6.45 x 10-1 m3/day while transmissivity ranged from 0.49 to 4.52m2/day and specific capacity from 18.41 to 117.92 m2/day. The specific yield varied between 78.62 and 87.26 m3/day. Classification based on transmissivity values shows a very low to low yield aquifer. This correlates well with the litholog which showed fractured shales as the groundwater bearing unit supplying water into the wells. Good correlation (correlation coefficient, R2) of 0.8753 was obtained between transmissivity and specific capacity. The hydraulic coefficient and transmissivity indicate that for sustainable aquifer productivity, boreholes in the area should be installed with low horse power pump size for domestic use. Key words: Pumping test, Aquifer, Hydraulic conductivity, Transmissivity, Specific capacity
International journal of engineering science technologies, Jul 20, 2022
The Geotechnical properties of soils in Uyo town were analyzed to determine the bearing capacity ... more The Geotechnical properties of soils in Uyo town were analyzed to determine the bearing capacity and generate maps for shallow and deep foundation designs. Eleven geotechnical boreholes were drilled to a maximum depth of 20 meters each across Uyo town. Standard penetration tests and cone penetration tests were also carried out on the field. Soil samples were retrieved during the field investigation for various laboratory tests including liquid limits, plastic limit, bulk density, shear strength and particle size distribution. The general soil profile consists of silty clays, sandy clays, and sand from top to bottom. The silty clays are firm, low compressibility clays with liquid limit and plastic limit percentages between 32%-45% and 10%-45% respectively, cohesion averages of 4˚ to 12˚ and angles of internal friction between 48KN/m2-68KN/m2. Ultimate bearing capacities of this horizon range from 354.6kN/m2 to 866.7kN/m2. The sandy clays are also firm, low to intermediate plasticity clays with liquid limit and plasticity indexes of 29%-42% and 9%-15% respectively. Their cohesion averages range between 50KN/m2-65KN/m2 and angles of internal friction between 6˚-12˚. The ultimate bearing capacities of this clay range from 482.5KN/m2 to 906.2KN/m2. The sand is a poorly graded, medium dense sand with standard penetration test N-values between 8 to 23. Pile bearing capacities of the sand gave ultimate and allowable bearing capacities between 10262.9KN-11510.2KN and 4105.2KN-4604.1KN respectively. The sand substratum is a suitable termination depth for piles.
International Journal of Engineering Science Technologies
The Geotechnical properties of soils in Uyo town were analysed to determine the bearing capacity ... more The Geotechnical properties of soils in Uyo town were analysed to determine the bearing capacity and develop maps for shallow and deep foundation designs, which may serve as field models, for the planning of site investigation programmes for foundation purposes. Eleven boreholes were drilled to a maximum depth of 20 meters each across Uyo town. Standard penetration tests and cone penetration tests were also carried out on the field. Soil samples were retrieved during the field investigation for various laboratory tests including liquid limits, plastic limit, bulk density, shear strength and particle size distribution. The general soil profile consists of silty clays, sandy clays and sand from top to bottom. The silty clays are firm, low compressibility clays with liquid limit and plastic limit percentages between 32%-45% and 10%-45% respectively, cohesion averages of 4˚ to 12˚ and angles of internal friction between 48KN/m2-68KN/m2. Ultimate bearing capacities of this horizon range ...
Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analyse... more Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analysed to determine their swelling and slaking characteristics and effect on pavement construction and stability of slopes. Engineering problems reported in areas underlain by the soils include pavement failure and landslides. Results show that for the Ekenkpon shale, Liquid Limit, Plasticity Index and free swell averaged 45%, 14%, and 23% respectively compared to values for Nkporo shale which were 45%, 14%, and 17% respectively. Montmorrilonite, illite and kaolinite are major mineral components of the soils. The undrained cohesion values of 47 to 49kN/m and angle of internal friction between 3 and 4 suggest low shear strength. The slake durability index of Ekenkpon shale was 41% compared to 8% for Nkporo shale. The index properties, mineralogy and the slake durability index imply that all the shales are soil-like, have moderate expansivity and are of low shear strength. They are susceptible ...
Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria... more Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2. Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to...
Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analyse... more Samples of Ekenkpon and Nkporo shales from the Calabar Flank in southeastern Nigeria were analysed to determine their swelling and slaking characteristics and effect on pavement construction and stability of slopes. Engineering problems reported in areas underlain by the soils include pavement failure and landslides. Results show that for the Ekenkpon shale, Liquid Limit, Plasticity Index and free swell averaged 45%, 14%, and 23% respectively compared to values for Nkporo shale which were 45%, 14%, and 17% respectively. Montmorrilonite, illite and kaolinite are major mineral components of the soils. The undrained cohesion values of 47 to 49kN/m 2 and angle of internal friction between 3 and 4 o suggest low shear strength. The slake durability index of Ekenkpon shale was 41% compared to 8% for Nkporo shale. The index properties, mineralogy and the slake durability index imply that all the shales are soil-like, have moderate expansivity and are of low shear strength. They are suscepti...
A natural gradient tracer test with sodium chloride as the injectate was conducted using one inje... more A natural gradient tracer test with sodium chloride as the injectate was conducted using one injection well and eleven observation wells in an oil-contaminated site in the study area. The aim was to characterize the site and to determine migration rates of the contaminants to provide information on their fate in groundwater resources in the area. The migration of the tracer was constantly monitored by sampling all the observation wells spaced 5 m from each other at 15-30 min intervals for a period of 6 days. The test soil layer is a clayey silty sand consisting of 50 % sand, 30 % silt and 20 % clay. The average static water level at the site is about 2.5 m. Gas chromatography fingerprinting showed that kerosene and diesel are the dominant fractions within the soil matrix. The arrival times of the breakthrough moments of the migrating tracer plume from two observation piezometers situated 2.0 and 7.22 m away from the injection well showed that the mean velocity in the longitudinal direction in the aquifer is 1.403 9 10 -3 ms -1 (121 m/day). The longitudinal and transverse dispersion coefficients of 2.45 9 10 -3 m 2 s -1 and 2.3 9 10 -3 m 2 s -1 were used to obtain longitudinal and transverse dispersivities of 1.78 and 1.64 m, respectively. High hydraulic conductivity denoted by the high migration rate of the tracer implies that contaminant at the site will migrate through the aquifer with relative ease. However, the significant clay fraction within the soil provides the medium for adsorption and partitioning of contaminants to the soil.
In this work, the properties of some basement rocks in Bansara area in the Nigerian sector of the... more In this work, the properties of some basement rocks in Bansara area in the Nigerian sector of the Bamenda massif which determine their suitability for the production of aggregate for construction works were assessed to evaluate their performance as pavement materials. ...
This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site... more This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site impacted by an unquantified volume of petroleum hydrocarbon where depth to groundwater level may be less than one metre during peak rainy season. Pre-remediation concentration of Total Petroleum Hydrocarbon in soils was 30,000mg/kg to 160,000mg/kg while post remediation values were below the intervention values of 5,000mg/kg, but still higher than the target values of 50mg/kg specified for the Petroleum Industry in Nigeria. Similarly, BTEX levels reduced from 5mg/kg to less than 1mg/kg in soil and from 400µg/l to ˂3µg/l in groundwater. Post-remediation Primary Aromatic Hydrocarbon concentrations reduced from 700mg/kg to 5mg/kg in soil and from 10µg/l to ˂3µg/l in groundwater. Seasonal fluctuations of the groundwater level imprinted a hydrocarbon smear of about 3-6m within the silty and sandy soil profile. The presence of the post-remediation residual contaminants at these concentrations...
This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site... more This work evaluated existing and potential adverse impacts in a remediated hydrocarbon spill site impacted by an unquantified volume of petroleum hydrocarbon where depth to groundwater level may be less than one metre during peak rainy season. Pre-remediation concentration of Total Petroleum Hydrocarbon in soils was 30,000mg/kg to 160,000mg/kg while post remediation values were below the intervention values of 5,000mg/kg, but still higher than the target values of 50mg/kg specified for the Petroleum Industry in Nigeria. Similarly, BTEX levels reduced from 5mg/kg to less than 1mg/kg in soil and from 400µg/l to ˂3µg/l in groundwater. Post-remediation Primary Aromatic Hydrocarbon concentrations reduced from 700mg/kg to 5mg/kg in soil and from 10µg/l to ˂3µg/l in groundwater. Seasonal fluctuations of the groundwater level imprinted a hydrocarbon smear of about 3-6m within the silty and sandy soil profile. The presence of the post-remediation residual contaminants at these concen...
In this work, the propert ies of some basement rocks in Bansara area in the Nigerian sector of th... more In this work, the propert ies of some basement rocks in Bansara area in the Nigerian sector of the Bamenda massif wh ich determine their suitability for the p roduction of aggregate for construction works were assessed to evaluate their performance as pavement materials. The rock materials evaluated were from Biotite-Granite, Gran ite-Gneiss, Schist and Greenstone rocks. The Biotite-Gran ite gave Aggregate Abrasion Value (AAV) of 22.0%, Aggregate Crushing Value (A CV) of 23.3%, Aggregate Impact Value (AIV) of 18.5% and water absorption of 0.54% while Granite-Gneiss has 27.0%, 26.1%, 22.8% and 0.73% and the Greenstone has 45.2%, 55.9%, 49.6% and 3.90% respectively. Although the Biotite-Granite and Granite-Gneiss possess the necessary criteria for use as construction aggregates, the Biotite- Gran ite is of better quality because of its exceptionally high strength value and low water absorption. The high resistance of Biotite-Granite and its low water absorption could be attributed to ...
Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria... more Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2. Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to A-2-4 subgroups of the AASHO classification. The overall implication of these composite engineering properties is that the non-lateritic soils rate as poor to fair subgrade materials.
The status of oil contaminated sites in the Niger Delta has been poorly studied; flow dynamics an... more The status of oil contaminated sites in the Niger Delta has been poorly studied; flow dynamics and fate of these hydrocarbon contaminants once released into the surface are unknown. The severity of this pollution problem depends upon the rate of migration of these organic and inorganic compounds through porous media. In this work, a model of contaminant migration patterns of non aqueous phase liquids (NAPLs) in the Niger Delta region using a small scale sodium chloride field test was designed to predict the fate and transport of contaminants. The migration pattern of the tracer was studied using the surfer software. The combination of vector grid map and the contour map layers enhanced the modelling of the magnitude and direction of groundwater flow, solute/contaminant migration. The models demonstrated that longitudinal advection was more pronounced than the transverse advection. The concentration peaks decreased progressively away from the injection well and revealed the attenuati...
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Papers by Akaha Tse
Development Goal 13.
Development Goal 13.