Refine
Document Type
- Doctoral thesis (7)
Has Fulltext
- yes (7)
Is part of the Bibliography
- no (7)
Language
- English (7)
Keywords
- Nigeria (7) (remove)
With the increasing consciousness of the value of wetland ecological and environmental functions and its fast rate of decline in the size of this important and rich ecosystem globally, the Niger Delta ecosystem has been reported to be undergoing tremendous change, hence the need for this research, to identify the challenges and proffer solutions. This study focuses on ascertaining if a change has occurred in the Upper Orashi Forest Reserved wetland, to know and evaluate the policies used in managing the wetland in the region and Nigeria. To ascertain the wetland change, land cover change detection was carried out using Geographic Information Systems and Remote Sensing to produce paradigm or data to detect change occurrence in the wetland area. Supervised classification of land use and land cover change was carried out using LANDSAT data from 2002, 2008, and 2019. Thereafter, the land cover transition was mapped for the period 2002 to 2019 and this was computed for the net land cover change for the period of study. The site was classified into three different classes and each class was analyzed using the land use and land cover change model formula. The result from this part shows that there is a consistent decrease in the wetland area for the period under review and in the other two identified classes, some interchangeable compositions were observed for the period of study. To validate this result, the opinion of experts and the host community is needed. Two sets of questionnaires were designed for experts and local community dwellers to sample their opinion in relation to the wetland and its management. The information collected was analyzed using Microsoft excel and the result shows that changes have occurred in the wetland of Upper Orashi Forest (decrease in size and other challenging issues with respect to policies and regulations). This study has identified critical challenging issues facing wetlands in the region or driving factors of wetland loss in the study area. Thereafter making recommendations that will help address these issues to actualize environmental sustainability and sustainable wetland in the region and Nigeria at large.
In order to integrate necessary interdisciplinary complexity, sustainability, defined targets and endpoints for reclamation progress, the objective of this research is to advance reclamation knowledge on (i) international scale and (ii) national scale, taking Nigeria as an example. On the international scale (i), a systematic reclamation threshold scale for assessing, evaluating, documenting, and monitoring reclamation progress was developed. The threshold stages begin from the initial state I0 down to degraded state D0 (depending on the type of mining). Reclamation starts with soil reconstruction R-2 up to revegetation R-1 (red zones) to reach minimum threshold R0 (amber zone). Beyond R0 are the green zones R1, R2, and R3 representing soil/abiotic condition, biological and improved threshold respectively. Adaptation of the threshold model to degraded ecosystems in national and international laws is recommended. On the national scale with Nigeria (ii), endowed with over 34 solid minerals and abundant crude oil, findings show that almost all mine sites are below the minimum threshold scale R0. The sites are adversely affected by Artisanal and Small Scale Mining (ASM), whereby, contamination and soil lithology disturbances are the state-of-the-art discussions. However, bioremediation (phytoremediation) is the most feasible remediation technique. Therefore, for the crude oil contaminated sites, this study highlights typical cogitation for large in-situ implementation and potential species for remediation. For the mineral resources, gold mining was the typical example. As a practical approach, experimental areas on an abandoned mining site (Site 1), an active mining site (Site 2) and an undisturbed vegetation site (Control) in southwestern Nigeria were mapped out to represent its mining and farming activities. On the sites, (a) the impacts of the ASM activities on the floristic association were assessed. (b) the potential of 2D Electrical Resistivity Tomography (ERT) was explored to characterize the horizontal and vertical landscape homogeneity of the mine sites, and lastly, (c) the study identified native high-accumulating plants growing on the sites that can be employed for phytoremediation. Thus, the results show that (a) the floristic association of the mine sites have been stressed and disturbed. (b) the resistivity structure of the sites shows that ASM has greatly impaired the lithological status of the sites. (c) out of the 9 considered species, Crinum jagus has the highest accumulation factor of 8.71, 37.47, 1.08 and 29.38 for Pb, Cd, Fe and Cu respectively. It is a recommendable novel plant in the tropics. However, future studies must verify its hyperaccumulator potentials, identify other high accumulating species and develop effective approaches and policies to curb ASM activities and enhance remediation in Nigeria.
In most studies on flood risk in Nigeria, priority is given to urban flood risk than rural flood risk. Smallholder farmers who mostly inhabit rural areas and flood plains are known to be at great risk of flooding, but to date, there have been no studies on the impacts they experience and how they cope with these impacts.
To establish the existence of significant change in precipitation in the study area, statistical analysis of precipitation data was conducted using linear regression and non-parametric Mann Kendall test. Landsat satellite images for 1986, 2003 and 2016 were obtained from the United States Geological Survey’s (USGS) website and used to collect and analyze data related to land use.
To determine flood risk in the context of land use change, the HEC-HMS model version 3.5 was used. Land use maps corresponding to 1986, 2003, and 2016 LULC conditions were analysed and prepared for the calculation of CN values using Soil Conservation Service (SCS-CN) method. CN map was prepared by integrating the maps of hydrologic soil groups and land use in ArcGIS software.
Based on selected morphological parameters, a flood risk map was developed for the study area. The morphologic flood risk showed that most parts of the basin face moderate flood risk. Higher runoff values were observed under 2016 LULC conditions mainly due to intense deforestation relative to those of 1986 and 2003. The results indicated that runoff and peak discharge are significantly affected by deforestation instead of changes in the rainfall pattern. Flood inundation maps of the study area were prepared for the flood events of 2012 and 2015. Maximum depth for the 2012 and 2015 flood events was calculated as 10.58m and 7.39m, respectively.
The socioeconomic aspects of the research were conducted using household survey method. Using snowball sampling techniques, 400 flood-affected households were selected. The results show that the adaptive capacity of smallholder farmers in the study area remains very low and hampered by several factors such as poverty and weakened social networks. The synopsis of the examined variables leads to the following conclusion: Instead of climatic factors – as one indicator of vulnerability – it is social inequality and poverty in the region as well as the structural economic differences between various groups that mainly drives vulnerability in the study area.
The existence of large deposit of crude oil in the Nigerian Niger-Delta accords the region a strategic position in the country’s economy. However, activities associated with the oil and gas industry have resulted in extensive and in some instances indelible damages on the ecosystems. The destructive effect of hydrocarbon on bionetwork necessitated this study that aimed at evaluating the potential of adopting microbial and biosurfactant technology as tools for bioremediation. The research involved gas chromatography monitoring of hydrocarbon degradation in polluted soil, microbiological/molecular identification of hydrocarbon degraders and the evaluation of biosurfactant production by indigenous bacteria. The performance of four treatments involving; co-treatment with mixed bacterial consortium and close-to-nature surfactants (Bioversal QF and Bioversal UK), treatments with mixed bacteria culture, single bacteria culture and treatment with close-to-nature surfactants only were evaluated for the mineralization of hydrocarbons contained in 500g of 2% crude oil contaminated soil supplemented with Na2HPO4*2H2O, KH2PO4 and NH4Cl as nutrient sources over a period of 20 weeks. Six indigenous biosurfactant producing and/or hydrocarbon degrading bacteria strains were isolated namely: Pseudomonas aeruginosa, Bacillus sp, Achromobacter sp, Stenotrophonas sp, Lysinibacillus sp. and Delftia sp. Molecular characterization of sequenced polymerase chain reaction products of these cultured bacteria using Nucleotide Basic Local Alignment Search Tool confirmed close relationships ranging from 98.83% to 100% with those on the NCBI databank. Co-treatment with mixed bacteria culture and Bioversal UK/Bioversal QF yielded synergetic impact that enhanced 73.35% and 71.52% degradation of total petroleum hydrocarbon respectively. Treatments with close-to-nature surfactants and with mix bacterial culture recorded 53.61% and 54.58%. The use of single bacteria strains resulted in the mineralization of 46% - 62.26% total petroleum hydrocarbon while their use as a consortium yielded 54%. Liquid chromatography-Mass spectrometry assessment of extracellular polymeric substances produced by cultured bacteria strains indicated the presence of rhamnolipids (L-rhamnosyl-3-hydroxydecanoyl-3-hydroxydecanoic acid with a mass of 504.654 Da) and lipopeptides (2-(Hydroxymethyl) phenyl 6-O-palmitoyl-β-D-glucopyranoside with a mass of 524.687 Da). Extracellular polymeric substances produced yielded emulsion index ranging from 70.70% to 75% and 39% to 65% with crude oil and heptane respectively. EPS yields ranging from 1.34 g/ml to 1.5 g/ml were recorded.
The impact of urbanization on the quality of drinking water sources is a challenge in many developing countries. In this research, the main source of drinking water was quantified, quality baseline defined, and a thematic decision support management tool developed to protect the quality using Aba, Nigeria. Data from primary and secondary sources were obtained from desktop search, empirical instruments, satellite data, hydrogeological investigations and water quality assessment. Geoscientific and statistical tools were used to analyse the landform, characterize the land use, and create management tools to protect the water source.
The results revealed that groundwater is the main source of water for both domestic and industrial uses. An average water consumption per capita rate of 35.9 l/day was estimated, which is low compared to the WHO recommendation. The landform and land-use analyses revealed that the area is low-lying, poorly drained, and the urban land-use is the fastest-growing class growing averagely at 0.6% /annum between 1986 to 2017. Some of the urban land-use practices that harm the quality of the groundwater were identified and mapped in a contamination hotspot map.
The results of the twenty-one quality indicators in the groundwater showed that the pH was acidic (3.7-5.6), total dissolved solids (TDS) ranged between 6.5 mg/l-364 mg/l. The mean concentrations of the remaining indicators were within the WHO limits for drinking water quality. But, the EC, TDS, chloride and nitrate revealed significant differences when tube-wells between densely and sparse built-up areas are compared. Again, four dominant water types were identified in groundwater. The Na-HCO3 water type was dominant mostly in the sparse built-up area and it is assumed as the background groundwater facies in the area. Whereas Mg, Ca-Cl, Na-Cl and Ca-HCO3 water types were predominant in the densely built-up area. The bacteriological assessments of drinking water from natural and alternative (i.e. beverages and packaged water) sources revealed the presence of E. Coli and Coliform bacteria in some samples of the natural water.
The groundwater quality distribution and vulnerability assessment maps were developed based on water quality index, and DRASTIC methodologies, respectively. The quality distribution map showed that > 98% of the area has a “suitable“ rating. While the vulnerability assessment map found that the groundwater has a “medium” baseline vulnerability covering about 80%. The differences in the results were due to some observed poor urban land-use practices in the area. Finally, a thematic decision support tool that delineates priority monitoring zones and suggests possible source protected areas tailored for the area was developed. This tool is cost-effective in protecting the groundwater quality and can be applied to other developing urban areas with similar physiological conditions.
The Nigerian government has commenced the development of minimum energy performance standards (MEPS) as part of measures to achieve the energy and emissions savings target established in Nigeria’s Nationally Determined Contribution (NDC) to the Paris Agreement. It is expected that the implementation of MEPS will also help to address the challenges of unreliability of electricity supply and facilitate the desired energy-efficient appliance market transformation. The MEPS currently covers the three most energy-consuming electrical products in households (lighting, refrigerators, and air conditioners). This research relied on data collected from the survey of 384 households in the case study area of Enugu to study the policy impacts of the current MEPS and identify the potential for its improvement. The research also, empirically, investigated policy and institutional barriers against appliance energy efficiency improvement in the country. Three different policy scenarios were conceptualized to model the policy impacts of current MEPS: a scenario assuming no MEPS or a business-as-usual (BAU) scenario, a policy scenario (PS) that considers the current MEPS, and an aggressive policy scenario (APS) that assumes the scaling up of the current MEPS to more stringent levels. The policy analysis modeling system (PAMS) was adopted to study the impacts of MEPS considering a policy implementation period of 2019 through 2030. The United Nations’ integrated policy framework was also adopted as evaluation criteria to identify policy gaps in the existing policy measures and the identification of possible policy overlaps was conducted using content analysis. Based on the results, the implementation of the current standards would reduce annual residential electricity demand in the surveyed households by 37% compared to BAU. National-level policy impacts show that the implementation of more stringent MEPS would contribute about 11.3% of the national emissions reduction target reached in Nigeria’s NDC. The research also finds out that key policy instruments (such as financial incentives) are still in their planning stages. Furthermore, the result from the content analysis reveals that the assigned institutional roles for the advancement of end-use energy efficiency are in some cases, not based on the statutory mandates of the respective institutions which create room for possible overlaps. To close the existing energy efficiency gaps and achieve effective energy-efficient appliance market transformation, the research underscores the need for a large-scale appliance market assessment to understand current baseline efficiency levels which will guide future policy designs and ensure that MEPS remain effective. The research also recommends key possible frameworks that can guide the design and implementation of financial incentive instruments to make energy-efficient investments more attractive.
Scientific data and results have to be accurate, precise and reliable and are subject to ever increasing scrutiny by regulators in industry, the environment and medicine, in validation and also in research and development. Given our numerous environmental problems, the need for accurate, precise and reliable results can not be overemphasized in environmental pollution control. In the light of this analytical environmentalists believe that there is need for a hierarchical scheme of methods to be used in environmental assessment studies. In this research the state and role of analytical instruments in environmental pollution control in Nigeria were studied with a focus on the state of the Nigerian environmental pollution control laboratories. A theoretical background of this work gives an overview of the state of the art of the environment globally and that of Nigeria. This work has established that, because mankind have put thousands of chemical substances to use in this century, there are many chemicals that have found their way into the natural environment in large quantities. Because of the nature of the environmental problems mankind is facing now, many researchers and manufacturers are dedicated to using and providing quality new and reliable instrumentation methods to ensure a healthy environment in our world. A brief study of Nigeria as the country of research is made to establish the background of possible problems. From the facts gathered in the literature Nigeria has the economic tools that it needs to put a good environmental management scheme in place, which includes good standards, laws, regulations and good analytical laboratories for compliance and monitoring. However the research has established that these economic tools are not effectively used in the management of environmental pollution control, especially monitoring of environmental pollutants. The research was undertaken by visiting four analytical laboratories involved in environmental pollution control in Nigeria, and three organizations that are the main environmental regulatory bodies in Nigeria. The analytical laboratories visited are those of Nigerian National Petroleum Corporation (NNPC) Kaduna, Ashaka cement factory, regional laboratory of the Federal Ministry of Water Resources Gombe, and the National Reference laboratory Lagos. In these laboratories and the organizations, results were collected in the laboratories, interviews were carried out and analytical instruments available were documented. It was discovered that, in these laboratories many standard analytical instruments needed for quality environmental pollution control and monitoring are lacking. Comparison of results generated in these laboratories with some from developed countries, revealed that many parameters measured in laboratories in developed countries are not measured in the research laboratories. The results obtained in these laboratories met Nigeria’ maximum limits in some cases, but exceeded it in many cases. It is the position of this work that the gap between the environmental analytical instruments found in literature and developed countries, and that found in Nigeria is very large and calls for concern. The environmental regulatory bodies in Nigeria have many laws, rules, regulations and standards for environmental pollution control. These regulations, standards, laws and rules were compared with what is obtained in other countries of the world, especially developed countries and found to be lacking in many areas. The way and manner the analytical methods are stated in the Nigerian regulations and standards are way below the developed countries standard. This research concludes that the regulations and standards have big influence on the kind of environmental analytical instruments found in the environmental analytical laboratories in Nigeria. The final conclusion this study has reached is that analytical methods, equipments, and standards on ground in Nigeria are not sufficient for the purpose of good environmental pollution control and monitoring. The situations as regards analytical instruments, analytical methods, standards and guidelines used in environmental pollution control in Nigeria do not favourably compare to international situations. It is therefore recommended that the need for validity and reliability in data collection, analysis, guidelines, standards and use of data in environmental pollution control needs to be addressed by the Nigerian Government if monitoring of the Millennium Development Goals and environmental pollution control in general is to be effective.