Crude Oil Pollution Research Articles

Clarifying the murk: unveiling bacterial dynamics in response to crude oil pollution, Corexit-dispersant, and natural sunlight in the Gulf of Mexico

The 2010 Deepwater Horizon (DwH) Oil spill released an enormous volume of oil into the Gulf of Mexico (GoM), prompting the widespread use of chemical dispersants like Corexit® EC9500A. The ecological consequences of this treatment, especially when combined with natural factors such as sunlight, remain unexplored in the context of marine bacterial communities’ dynamics. To address this knowledge gap, our study employed a unique metaproteomic approach, investigating the combined effects of sunlight, crude Macondo surrogate oil, and Corexit on GoM microbiome across different mesocosms. Exposure to oil and/or Corexit caused a marked change in community composition, with a decrease in taxonomic diversity relative to controls in only 24 hours. Hydrocarbon (HC) degraders, particularly those more tolerant to Corexit and phototoxic properties of crude oil and/or Corexit, proliferated at the expense of more sensitive taxa. Solar radiation exacerbated these effects in most taxa. We demonstrated that sunlight increased the dispersant’s toxicity, impacting on community structure and functioning. These functional changes were primarily directed by oxidative stress with upregulated proteins and enzymes involved in protein turnover, general stress response, DNA replication and repair, chromosome condensation, and cell division. These factors were more abundant in chemically treated conditions, especially in the presence of Corexit compared to controls. Oil treatment significantly enhanced the relative abundance of Alteromonas, an oil-degrading Gammaproteobacteria. In combined oil-Corexit treatments, the majority of identified protein functions were assigned to Alteromonas, with strongly expressed proteins involved in membrane transport, motility, carbon and amino acid metabolism and cellular defense mechanisms. Marinomonas, one of the most active genera in dark conditions, was absent from the light treatment. Numerous metabolic pathways and HC-degrading genes provided insights into bacterial community adaptation to oil spills. Key enzymes of the glyoxylate bypass, enriched in contaminant-containing treatments, were predominantly associated with Rhodobacterales and Alteromonadales. Several proteins related to outer membrane transport, photosynthesis, and nutrient metabolisms were characterized, allowing predictions of the various treatments on biogeochemical cycles. The study also presents novel perspectives for future oil spill clean-up processes.

Microbial community response to biostimulation and bioaugmentation in crude oil-polluted sediments of the Persian Gulf

The Persian Gulf is a transit point for a lot of crude oil at the international level. The purpose of this research is to compare two methods of biostimulation and bioaugmentation for degradation of sediments contaminated with crude oil in the Persian Gulf. In this research, six types of microcosms were designed (Sediments from Khark Island). Some indicators such as: the quantity of marine bacteria, enzyme activity (Catalase, Polyphenol oxidase, Dehydrogenase), biodiversity indices and the percentage of crude oil degradation were analyzed during different days (0, 20, 40, 60, 80, 100 and 120). The results of this research showed that the highest quantity of heterotrophic and crude oil-degrading bacteria was found in the sixth microcosm (SB). This microcosm represents a combination of two methods: bioaugmentation and biostimulation (3.9 × 106 CFU g−1). Following crude oil pollution, the activity of catalase and polyphenol oxidase increased and the dehydrogenase enzyme decreased. The bioaugmentation microcosm exhibited the highest activity of enzymes among all the microcosms studied. Predominant bacteria in each microcosm belonged to: Cellulosimicrobium, Shewanella, Alcanivorax and Cobetia. The highest degradation of crude oil is related to the Stimulation-Bioaugmentation microcosm (SB). The statistical results of this research proved that there is a significant relationship between the type of method chosen for biodegradation with the sampling time and the quantity of marine bacteria. The results of this research confirm that crude oil pollution in the Persian Gulf sediments can be reduced by choosing the proper bioremediation method.

A superhydrophilic/air superoleophobic sponge based on low-temperature vacuum evaporation deposition modification for saving marine crude oil pollution and leakage

Oil pollution and crude oil leakage in the ocean have severely impacted marine ecology. The emergence of super-wetting materials provides a new approach to addressing the issue of oil leakage. Chemical vapor deposition, which can be applied to prepare super-wetting materials, is a method that can modify uniformly and enhance the stability of the material, while mostly needing to be performed at high temperatures. In this study, melamine sponge (MS) was preliminarily modified by low-temperature vacuum evaporation deposition (LTVED) of hydrolyzed γ-mercaptopropyl triethoxy silane (KH580). The nano-silica and FS-50 were stepwise coated on the MS skeleton by a simple immersion-drying process. A superhydrophilic/air superoleophobic sponge (MS-KCSiF) as obtained with water contact angle of nearly 0° and crude oil contact angle of approximately 154° in the air, which can retain the wetting properties after immersion in different chemical solutions, ultraviolet irradiation aging, and mechanical destruction like cutting, twisting, bending, and pressing. Its efficiency for high-viscosity crude oil-seawater mixtures was maintained at over 96 % after 20 cycles. Empowered with the shape of mortise and tenon joint structure, MS-KCSiF can scoop up spilled crude oil from the sea surface. This strategy provides a new idea for the construction of super-wetting materials and oil spill collection.

Investigation of strength and durability performance of concrete with varying crude oil waste ratios

The influence of crude oil (CRO) pollution on concrete compressive strength and durability performance is evaluated in this work. Due to CRO contamination on its compositions, concrete exposed to oil-prone areas may lead to considerable changes in its properties. Experimental work has been conducted, and several cubes of concrete with varying ratios of CRO pollution were treated to study the impact of pollution on the mechanical characteristics of the concrete. The current research methodology consists of preparing contaminants by mixing CRO in different ratios with fine aggregates and mixing it with other raw materials to produce polluted concrete. Twelve CRO ratios (0, 1, 2, 2.5, 3, 4, 5, 6, 10, 15, 20, and 25%) were utilized to test typical concrete slump, compressive, and tensile strength. Then, the same concrete procedure and testing were repeated by utilizing 2% CRO in the case of reactive powder concrete. The chemical test was also utilized to identify the changes in concrete composition for the three samples (standard concrete without CRO, standard concrete with 2% CRO, and reactive powder concrete sample). The experimental tests illustrated that a ratio of 2% of CRO in standard concrete improves compressive and tensile strength, while utilizing the same ratio in reactive powder concrete reduces strength. On the other hand, utilizing 2% CRO illustrates that the internal sulfate amount has been increased for both normal and reactive powder concrete compared with normal concrete samples without CRO, which refers to a reduction in concrete durability.

Beyond the spill: the hidden effects of crude oil pollutants on fish behaviour

Beyond the spill: the hidden effects of crude oil pollutants on fish behaviour

Systematic Intrinsic Biodegradation Studies of Crude Oil Contaminated Soil of Bdere Community in South-South, Nigeria

Crude oil pollution is a perennial environmental menace that has bedevilled the South-South ecosystem of Nigeria. This study was aimed at using gas chromatography-mass spectrometry (GC-MS) technique to investigate the biodegradation capabilities of nine bacterial cultures on crude oil residues in Bdere area in South-South, Nigeria. These microorganisms include Pseudomonas aeruginosa, Bacillus subtilis, Bacillus cereus, Micrococcus spp, Pseudomonas putida, Clostridium spp, Bacillus spp, Streptococcus spp, and Serratia spp. The results from the microbial-degraded samples were compared with an abiotic control. The findings reveal that the total petroleum hydrocarbon (TPH) in the microbial-treated samples was significantly attenuated compared to the control, confirming the microrganism's ability to degrade crude oil components. The primary degradation pathway involved biological oxidation of the aliphatic hydrocarbons, transforming them to primary alcohols, aldehydes, and fatty acid derivatives. Degradation was also observed across a wide range of short and long-chain alkanes, aromatic hydrocarbons, and polycyclic aromatic hydrocarbons (PAHs). However, some resistant compounds persisted, and certain degradation products inhibited the rate of further biodegradation. The generation of new metabolites and intermediates confirmed the effective microbial remediation. These findings expand our understanding of microbial degradation of hydrocarbons, offering potential strategies for environmental remediation of oil-contaminated sites.

Microbial diversity and oil biodegradation potential of northern Barents Sea sediments

The Arctic, an essential ecosystem on Earth, is subject to pronounced anthropogenic pressures, most notable being the climate change and risks of crude oil pollution. As crucial elements of Arctic environments, benthic microbiomes are involved in climate-relevant biogeochemical cycles and hold the potential to remediate upcoming contamination. Yet, the Arctic benthic microbiomes are among the least explored biomes on the planet. Here we combined geochemical analyses, incubation experiments, and microbial community profiling to detail the biogeography and biodegradation potential of Arctic sedimentary microbiomes in the northern Barents Sea. The results revealed a predominance of bacterial and archaea phyla typically found in the deep marine biosphere, such as Chloroflexi, Atribacteria, and Bathyarcheaota. The topmost benthic communities were spatially structured by sedimentary organic carbon, lacking a clear distinction among geographic regions. With increasing sediment depth, the community structure exhibited stratigraphic variability that could be correlated to redox geochemistry of sediments. The benthic microbiomes harbored multiple taxa capable of oxidizing hydrocarbons using aerobic and anaerobic pathways. Incubation of surface sediments with crude oil led to proliferation of several genera from the so-called rare biosphere. These include Alkalimarinus and Halioglobus, previously unrecognized as hydrocarbon-degrading genera, both harboring the full genetic potential for aerobic alkane oxidation. These findings increase our understanding of the taxonomic inventory and functional potential of unstudied benthic microbiomes in the Arctic.

Effects of natural and prolonged crude oil pollution on soil enzyme activities

In this study the effects of natural and long-term oil pollution levels (H: high, M: moderate and L: low) on the activity of lipase, β-glucosidase, urease, phosphatase, and dehydrogenase were analyzed. For this purpose, 120 oil-contaminated soil samples were collected from four locations located in oil-rich region of the west of Iran (Kermanshah province, Iran). After determining the physicochemical characteristics of soils, microbial counting and enzyme activities were measured. To determine the total bacterial population and bacteria involved in crude oil decomposition, bacterial counting was done in NA and CFMM culture media, respectively, which had a direct relationship with the increase in crude oil content. The average percentage of crude oil measured by Soxhlet method was 4.03%, 9.95% and 22.50% respectively for L, M and H levels. The results showed that the bacterial population increased with the increase of the contamination intensity. All the studied enzymes, except urease, had the highest activity in heavily polluted soils (H soil), and their lowest activity was observed in lightly polluted soils (L soils). Location 1 had the highest bacterial population as well as the highest activity of dehydrogenase (52.13 μg TPFg−1 h−1), acid phosphatase (35.86 μg PNPg−1 h−1), alkaline phosphatase (78.13 μg PNPg−1 h−1), lipase (92.58 μ MLA g−1 h−1) and β-glucosidase (21.67 μg PNPg−1 h−1) enzymes. In the soil samples of location 4, which had the lowest number of bacteria, the highest activity of urease enzyme (592.36 μg NH4g−1 h−1) was obtained. Principal components analysis (PCA) was also performed and 67% of the cumulative of the samples could be explained by the first two components (biochemical and physical). The findings of this research showed that natural and prolonged crude oil pollution caused the selection of oil-resistant microbial communities, and therefore we saw their positive response to the presence of oil compounds and increased enzyme activity other than urease activity.

Hydrophobic modified melamine sponge for highly effective remediation of crude oil in water and soil

Crude oil pollution in water and soil has resulted in considerable environmental damage. The utilization of hydrophobic and oleophilic sponge materials for the treatment of crude oil pollution has garnered significant interest, owing to their excellent selective adsorption performance. In this paper, superhydrophobic and superoleophilic sponges (SMF) are prepared by a simple silane hydrolysis-thermal curing method, which is low-cost, environmentally friendly, large-scale preparation, acid and alkali-resistant, and mechanically stable. They can be used for the remediation of oil pollutants in water and soil simultaneously, and show high efficiency, excellent stability, and biosafety. Under appropriate circumstances, SMF is capable of adsorbing up to 82.7 g/g of crude oil in water and eliminating over 70.0 % of crude oil in soil, while exhibiting exceptional recycling performance. Notably, this study introduces a novel technique that alters soil viscosity by controlling soil water content, in conjunction with SMF, for the removal of crude oil in soil. Consequently, SMF shows great promise for practical application in the remediation of oil pollutants in both water and soil.

Assessment of Biostimulation and Bioaugmentation on Crude Oil-Polluted Sediments Microbial Community of Persian Gulf: A Microcosm Simulation Study

The Persian Gulf is a transit point for a lot of crude oil at the international level. The purpose of this research is to compare two methods of biostimulation and bioaugmentation for degradation of sediments contaminated with crude oil in the Persian Gulf. In this research, six types of microcosms were designed (sediments of Khark Island). Some indicators, such as the quantity of marine bacteria, enzyme activity (catalase, polyphenol oxidase, and dehydrogenase), biodiversity indices, and the percentage of crude oil degradation were analyzed during different days (0, 20, 40, 60, 80, 100 and 120). The results of this research showed that the highest quantity of heterotrophic and crude oil-degrading bacteria to the sixth microcosm (stimulation–bioaugmentation), a combination of two methods bioaugmentation and biostimulation (3.9 × 106 CFU g−1). After crude oil pollution, the activity of catalase and polyphenol oxidase increased, and the dehydrogenase enzyme decreased. Bioaugmentation microcosm has the highest activity of enzymes among all studied microcosms. Predominant bacteria in each microcosm belonged to Cellulosimicrobium, Shewanella, Alcanivorax, and Cobetia. The highest degradation of crude oil is related to the stimulation–bioaugmentation microcosm. The statistical results of this research proved that there is a significant relationship between the type of method chosen for biodegradation with the sampling time and the quantity of marine bacteria. The results of this research confirm that crude oil pollution in the Persian Gulf sediments can be reduced by choosing the proper bioremediation method.

New insights of crude oil biodegradation construction by microbial consortium B10: Responded substrates, genomics, biodegradation mechanism and pathways

Crude oil pollution caused by production and living demands has existed for decades, which adverse to ecological security and human health. Microbial degradation of crude oil is a green and effective remediation method. This study is intended to develop a microbial consortium based on the commonness and differences of key genes and response substrates of the strains to efficiently degrade crude oil. Four crude oil-contaminated soil dwelling bacteria, CO1, CO2, CO6 and CO7, were isolated whose crude oil degradation and emulsification performance were evaluated. Subsequently, revealing their genomic characteristics and response substrates, the key genes of CO1 were mapped to genes alkB, hcaD; CO2 were located at genes andAd, andAc; CO6 were mapped to genes ladA, alkM, pcaH, benB-xylY and CO7 were located at gene cypd-E. Consortium of Ochrobactrum.sp, Pseudomonas aeruginosa and Bacillus.sp were selected as microbial consortium B10. Compared with single strain, the crude oil removal efficiency of B10 via RSM method optimizing is up to 51.58 % in 6 days, where the C11-C18 removal rate is up to 78.51 %. Besides, the biodegradation rates of C26-C29 and C33-35 increased by 36.20 % and 30.51 %, respectively. The possible metabolic pathways of crude oil were proposed, including aldehyde bond (H-C=O) and ketone bond (C-O-C) hydrodehydration, ring opening of cyclic ether, C-C bond oxidation of benzene ring and ring-opening hydrolysis of gentisic acid reactions. Altogether, this study provides a new insight into high-performance microbial consortia construction in crude oil biodegradation.

Integrated approach for efficient crude oil bioremediation: Bacterial consortium development, mathematical modelling and scalable bioprocess design

Crude oil pollution has a significant impact on the surrounding ecosystem, making its remediation an urgent necessity due to the waste discharge and seepage from petroleum industries. To address this issue, we developed an efficient bacterial consortium from strains isolated from petroleum refinery waste. These strains were identified as genera Pseudomonas, Ochrobactrum, Alcaligenes, and Bacillus, specifically chosen for their ability to biodegrade crude oil. Through the optimization of process parameters, we enhanced the biodegradation efficiency of the bacterial consortium. Furthermore, the scalability of the biodegradation process was established in 6L batch bioreactor, which featured a total TPH removal of 80.10 %. The independently obtained substrate inhibition data and bioreactor batch kinetics data were utilized to develop a batch mathematical-model. The mathematical model accurately simulated batch bioreactor kinetics and was further extrapolated to design a fed-batch nutrient feeding strategy. Implementing this strategy, based on the model, led to a higher TPH removal rate of 86.86 % in a constant feed batch-fed-batch approach, as validated through experimental implementation. Validation of the biodegradation process was confirmed through Gas Chromatography-Mass Spectrometry (GC–MS) analysis of degraded samples, which confirmed the biodegradation of petroleum hydrocarbons. The increased rates of oil biodegradation achieved through our developed consortium and advanced bioprocess offer a promising solution for the effective clean-up of oily pollutants present in petroleum wastewater and oil spillage scenarios.

Post Reclamation Evaluation of Residual Hydrocarbons in Crude Oil Contaminated Soil Using Gas Chromatographic Techniques and Plant Growth Indices

The present study was undertaken to evaluate the post-reclamation of crude oil-contaminated soil using gas chromatographic technique and plant growth indices. Enrichment techniques, turbidometric test, plasmid curing test, classical identification method, gas chromatographic flame ionization detection technique and plant growth indices were carried out using standard procedures. The results indicated that 22 of the isolates were observed to have high pollutant degrading potentials (A600nm > 0.3) due to their crude oil utilization ability. The results also indicated that isolates which were able to degrade crude oil belonged to genera Bacillus, Pseudomanas sp., Ochrobacterium sp. and Enterobacter sp. Moreso, the remediation percentages recorded were 98 %, 80 %, 21 % and 98 %, 78 % and 22 % for the respective crude oil pollution (3 %, 5 % and 10 %) for soil inoculated plasmid borne bacteria whereas soil inoculated with plasmid cured bacterial cultures had 65 %, 52 %, 11 % and 65 %, 50 % and 20 % degradation of the same concentration of the total petroleum hydrocarbon after 60 days for both Phaseolus vulgaris and Glycine max plant seeds, respectively. The remediation percentages in the uninoculated controls include 3 %, 5 %, 10 % and 12 %, 9 % and 5 % across the pollutions for both plant seeds. A significant (P < 0.05) increase in the growth parameters of the leguminous plants like percentage germination, mean plant shoot length, mean plant root length, plant fresh weight and number of root nodules were seen more in the soil microcosms inoculated with plasmid-borne bacteria than microcosm inoculated with culture of plasmid cured bacteria across all crude oil dilutions. Crude oil had a dose-dependent negative effect on the mean bacterial counts of each of the polluted soil containing the two different plants. Thus, the study clearly suggests that the selected hydrocarbon bacterial degraders could be effectively exploited in the remediation of crude oil-polluted sites.

Maize cob (Zea mays) as natural biomass sorbent for crude oil biosorptive removal from contaminated seawater: Taguchi process optimization and biosorptive removal mechanism.

Crude oil pollution poses a serious threat to the aquatic environment. Hence, there is an increasing interest in developing an efficient cleaner process technique for oil spill cleanup via agricultural biomass waste-organic sorbent utilization. This work evaluated the effects of independent biosorptive removal at three varying levels (initial concentration of crude oil (Z1, 7.8-15.6 g/L), seawater-oil temperature (Z2, 25-45 °C), sorbent dose (Z3, 1-3 g), and sorbent particle size diameter (Z4, 1.18-4.72 mm)) on the biosorptive removal efficiency and biosorptive capacity performance of maize cob sorbent for crude oil biosorptive removal from seawater. Experiments were designed based on Taguchi orthogonal array experimental design (L9(34)) to study the effects and process optimization. The results revealed that the maize cob sorbent's crude oil biosorptive removal efficiency is related to Z1, Z3, and Z4, while the biosorptive capacity is related to Z1 and Z3. The optimum biosorptive removal efficiency and the biosorptive capacity values were 96.53% and 12.64 g/g, respectively, achieved at optimum factors of Z1 (7.8 g/L), Z3 (3 g), and Z4 (1.18 mm), as well as at Z1 (15.6 g) and Z3 (1 g). The isotherm and kinetic data, respectively, followed the Langmuir isotherms and the pseudo-second-order kinetics with a maximum monolayer biosorptive capacity of 23.31 g g-1. The mechanism of biosorptive crude oil removal was by physical sorption and film diffusion control. Therefore, the maize cob represents an inexpensive and effective natural sorbent for oil spill removal from water bodies.

Blood Plasma Concentration of Heavy Metals in Under Five Children in Niger Delta, Nigeria

Environmental stressors such as pollution are major sources of heavy metal toxicity in humans. Biomonitoring studies are necessary for quantifying the body burden of these metals (As, Cd, Cr, Pb, Hg) of toxicological concern and their health effects especially for communities consistently exposed to crude oil pollution. This study investigated the level of heavy metals in the blood plasma of under-five children living in crude oil-polluted and non-crude oil-polluted environments in the Niger Delta, Nigeria. This cross-sectional study was conducted in 3 crude oil polluted communities in Gokana, Rivers State (B. Derek, K. Dere, Bomu) and 3 non-crude oil exploration communities in Ideato North LGA of Imo State (Umukegwu, Umuezeaga, Owerre-Akokwa) assigned as control; both States are in Niger Delta region of Nigeria. Ethical approval was obtained from the University of Port Harcourt Ethical Committee. A total of 78 children were recruited from Gokana (male =17, female= 22) and Ideato (Male=15, female=24) using multi-clustered sampling method. Standard methods of heavy metal analysis using atomic absorption spectrophotometer were used to analyze the samples. From the results, the concentration of Cr and Cd in the blood plasma of Gokana male was 2.81mg/kg and 3.19mg/kg while Ideato male was 0.497mg/kg of Cr and Cd was not detected. Gokana female was 1.22mg/kg for Cr and 0.92mg/kg for Cd. It was concluded that under-5 children living in crude oil-polluted communities of the Niger Delta region of Nigeria have high positive levels of heavy metals (Cr, Cd and AS). Health effect of the exposures is advised considering the sensitivity of the study population

Blood Plasma Concentration of Polycyclic Aromatic Hydrocarbons in Under Five Children in Niger Delta, Nigeria

PAHs are known carcinogens associated with immune system suppression, skin irritation, allergic reactions, respiratory problems, mutagenic issues and are generally toxic to humans. In this study, we assessed the presence and proportions of PAHs in the blood plasma of under-five children living in crude oil-polluted environment in Ogoniland, Niger Delta region of Nigeria. Communities resident in close proximity to crude oil exploration sites are constantly faced with environmental, socio-economic and health consequences of crude oil pollution. People can be exposed to PAHs through multiple routes including inhalation, ingestion and dermal contact. Ethical clearance for this study was obtained from the Ethics Committee, University of Port Harcourt. A total of 78 children were recruited from Gokana (male =17, female= 22) and Ideato (Male=15, female=24) using multi-clustered sampling method. Standard procedures were observed in this study. Results obtained were compared with under five children living in non-oil polluted environments within the Niger Delta province. The overall average PAHs was 0.331±0.383 mg/kg for Gokana males and 0.058±0.057mg/kg for Ideato males; overall average PAHs was 0.514±0.373 mg/kg for Gokana females and 0.100±0.049 mg/kg for Ideato female; overall average PAHs was 0.423±0.383 mg/kg Gokana and 0.081±0.057 mg/kg for Ideato. Under-five children in Ogoniland showed positive blood plasma PAHs higher than the comparison group in Ideato. However, carcinogenic PAHs were below levels of concern in the study population. The male gender showed higher positive PAHs than the female gender. Further studies on inflammation, stress factors and overall health status are recommended considering the vulnerability of the study population.

Studies on the ecological succession of microorganisms during bioremediation of hyper-toxic crude oil polluted soil using five amendments

Dangerous impact of crude oil in the environment is a common knowledge and its spillage has been controlled using both chemical and biological methods. Bioremediation however, is most advocated because of its environmental friendliness and sustainability. The present study sought to identify and monitor successions, and diversity of microorganisms elicited by five amendments in the bioremediation of hypertoxic crude oil pollution. Five amendment patterns which incorporated 200 g each of saw dust, wood chip, compost, N.P.K. fertilizer and poultry droppings; were used to stimulate biodegradation in 50% crude oil contaminated soil, and their respective microbial counts and microbial successions were monitored over a period of eight months. Statistical analyses were conducted using SPSS version 21 software. Poultry droppings amendment had the highest significant (p<0.05) bacterial and fungal counts. Bacillus subtilis, Stenotrophomas maltophilia and Pseudomonas aeruginosa were the predominant bacteria observed during the microbial succession studies across the amendment microcosms, while Aspergillus flavus, Penicillium citrinnum and Fusarium solani were the predominant fungal isolates. It was observed that the hyper-toxic concentration of the crude oil impacted the diversity and succession of the microbes across all the amendments used when compared to the control sample.

Effect of Crude Oil Pollution on Artisanal Fishing in Asari- Toru, Akuku-Toru and Degema Local Government Areas of Rivers State, Nigeria

This study analyzed the effect of crude oil production on artisanal fishing in selected local government areas of Rivers State. Purposive and random sampling technique were used in selecting respondents for the study. The sample size for the study was made up of 90 artisanal fishing folks. Data were elicited from fishing folks with a structured questionnaire which were administered to the respondents. Percentage, mean, costs and returns and multiple regression were used for the analyses of data. The result showed that the mean age of respondents was 40 years, while the mean house hold size was 6 persons. The result also showed that majority of the respondents had primary education and that most respondents had no access to credit facilities to enable them purchase fishing equipment for their operations. Also, majority (66.7%) were members of cooperative society while majority (71%) reported incidence of oil spillage in the study area. The regression analysis also revealed that the output of individual fishing households is significantly influenced by variables, namely, capital, labour, operating costs, fishing experience and oil spill. There is the need for policies that could compel oil companies to minimize oil spill in the farmers’ fishing environment.

Geotechnical Stabilization Potential of Cement Admixed with Rice Husk Ash on the Crude Oil Polluted Laterite Soil: A Case Study of Ebendo, Delta State, Nigeria

Crude oil pollution of the environment is one of the greatest concerns to Nigeria’s oil-rich Niger Delta and most oil producing regions of the world, with far-reaching effects on the ecosystems. In this study, the influence of oil pollution on geotechnical properties of laterite soil and possibility of stabilization with rice husk ash (RHA) and ordinary Portland cement (OPC) were investigated. Soil sample categorized as A-2-6 and CL was artificially contaminated with 0, 2, 4, 6, 8, and 10% crude oil. The consistency limits, specific gravity (SG), Compaction, Uniaxial compressive strength (UCS) and California Bearing Ratio (CBR) tests were carried out on both uncontaminated and contaminated soil samples. The 10% contaminated specimen was further stabilized with admixture of OPC and RHA using different percentages (0-10%) by mass of soil. A significant decrease in SG, maximum dry density (MDD), CBR and UCS was revealed but with an increase in consistency limits and optimum moisture content (OMC) as the volume of crude oil increased from 0 to 10%. However, stabilization of the contaminated soil with OPC and RHA improved the soaked CBR and UCS. The addition of OPC (0-10%) enhanced the UCS and CBR of the 10% polluted soil from 25-119 kN/m2 and 2-18.3%, respectively, while the treatment with RHA increased the UCS and CBR values from 25-60 kN/m2 and 2-4.4%. The results of research clearly show that oil contamination had considerable influence on soil properties but addition of 10% RHA or 8% OPC can be adopted to restore and enhance the geotechnical properties of the polluted laterite soil.

Phycoremediation of crude oil polluted water from selected water sources in Ogoniland, Rivers State, Nigeria.

Crude oil exploitation in the Niger Delta, particularly in Ogoniland, brought environmental devastation occasioned by petroleum pollution, as farmlands and water sources were destroyed. This study was designed to remediate crude oil contaminated water obtained from water sources in Ogoniland using two green algal species. Thirty water samples were collected from eight different water sources. The samples were analysed for total petroleum hydrocarbon (TPH) using gas chromatography/flame ionization detector (GC/FID). Algal samples were collected from Ogba River and at wetland in Military Hospital Benin, Edo State, Nigeria. The algal samples were identified, screened, optimized and grown in Bold basal medium. Results obtained from the determination of TPH showed that the infiltrated pond (Exc) sample site had the highest concentration among all the sites sampled with 198.8329 μg/L, R2 with 134.1296 μg/L, R1 with 108.9394 μg/L, R3 with 105.8011 μg/L, R4 with 98.442 8 μg/L, the hand-dug wells (Wll) had 9.6586 μg/L while the borehole (Bhl) had the lowest with 1.8310 μg/L. It was deduced that pollution of water sources was principally because of pollutants washed from the soil environment into the open surface water sources via run-off rather than through the seepage from the underground aquifers, incriminating illegal oil mining and artisanal refining. Results obtained from the analysis of algal growth medium indicated that the two algal species were able to absorb the hydrocarbon contaminants, albeit at different rates, corresponding with the algal growth rate. Analysis of algal biomass after 4 weeks of remediation showed that from the initial 10.27 μg/20 mL added to the growth medium, the highest TPH mean value of 0.490 μg/20 mL was extracted from Ulothrix zonata (F.Weber & Mohr) Kützing biomass grown in Exc compared to 0.344 μg/20 mL of TPH extracted from Chlorella sorokiniana Shihira & R.W.Krauss grown in the same sample site. Also, Ulothrix zonata had higher TPH yield 0.023 μg/20 mL in Bhl compared to Chlorella sorokiniana 0.021 μg/20 mL of TPH from the same water source. This result indicated Ulothrix zonata had superior TPH phycoremediation ability to Chlorella sorokiniana. While the present study calls for deployment of the algal species for field trial, it is strongly recommended that crude oil pollution should be discouraged.