Concentrations Of Crude Oil Research Articles

Bioaccumulation Potential of Cynodon dactylon Linn. in Crude Oil Contaminated Soil.

A greenhouse experiment was conducted to investigate the growth of Cynodon dactylon Linn. in soils contaminated by various concentrations of crude oil with a view to assessing its phytoremediating potential. The crude oil prepared at different concentrations of 0.0, 2.5, 5.0, 7.5, 10.0 and 12.5 (w/v) acted as contaminants on 3kg each of air-dried soil collected from the Obafemi Awolowo University Biological garden which is rich in organic matter. Each treatment was replicated 10 times in complete randomized design. Significantly (p<0.05) highest residual total petroleum hydrocarbon content (THC) uptake (39.26 ppm) was obtained in the plant at 12.5 ml contamination with the least residual total petroleum hydrocarbon content uptake (12.79 ppm) obtained at 2.5 ml contamination. With increased contamination, there was positive correlation with residual total petroleum hydrocarbon content uptake in the plants. No detectable amount of petroleum hydrocarbon content was found in the soil at the end of the experiment. The study concluded that C. dactylon plant could be effectively used in the phytoremediation of crude oil contaminated soil without addition of soil amendment.

Rheological Assessment of Oil-Xanthan Emulsions in Terms of Complex, Storage, and Loss Moduli.

This experimental assessment was carried out to study the viscoelastic performance of crude oil-xanthan emulsions employing a RheoStress RS100 rheometer. Crude oil with a concentration range of 0−75% by volume was used to prepare the oil-gum emulsions. Two xanthan gums of Sigma and Kelzan were added in the emulsions with concentration ranges of 0−104 ppm. The linear viscoelastic ranges of all the tested oil-gum emulsions were found in the range of 0.1−10 Pa. Thus, the experimental tests were completed within the linear viscoelastic range of 1 Pa. The complex modulus increased gradually and steadily with frequency and gum concentration for all the examined emulsions. The addition of crude oil into the lighter xanthan concentration of <103 ppm provided almost the same behavior as the xanthan solution, whereas the presence of crude oil within the higher xanthan concentrations significantly stimulated the measured values of the complex modulus. For lower gum concentrations of up to 1000 ppm, oil concentration displayed no effect on both the storage and loss moduli, whereas for gum concentrations higher than 1000 ppm, both moduli increased gradually with crude oil concentration.

Heamatological Changes Associated with Exposure of Catfish (Claria gariepinus) to Crude Oil

The effect of crude oil on some haematological parameters were studied in African catfish (Clarias gariepinus). A total of 30 catfish were grouped into 6 groups containing 5 catfish each. They were held for three (3) days in 5 different mixtures of crude oil polluted water (0.25%, 0.5%, 0.75%, 1%, and 1.5% v/v). Catfish in the control group were held in borehole water. At the expiration of 3 days, blood samples were collected and analysed. The red blood cell (RBC) count reduced with increasing concentration of crude oil, indicating an anaemic condition. This decrease also affected dependable factors such as packed cell volume (PCV), haemoglobin (Hb), mean corpuscular haemoglobin (MCH), and an increase in mean corpuscular haemoglobin concentration (MCHC). Furthermore, white blood cells (WBC) decreased, indicating susceptibility to stress and infection. Overall, the results indicated that exposure to crude oil has serious consequences on haematological parameters of catfish which may be attributed to the toxic components of crude oil. Keywords: Crude oil, Clarias gariepinus, RBC, PCV, Hb, MCH, MCHC, WBC

Alterations in energy metabolism, total protein, uric and nucleic acids in African sharptooth catfish (Clarias gariepinus Burchell) exposed to crude oil and fractions

Water contamination by crude oil is a growing challenge and little is known about the probabilistic and non-probabilistic ecosystem and species consequences. Therefore, research aimed at understanding species survival strategy in crude oil-contaminated environments with focus on cellular metabolic alterations and dynamics is vital. This study assessed the alterations in lactate dehydrogenase (LDH), glucose (GLU), glucose-6-phosphate dehydrogenase (G-6-PDH), total protein (TP), uric and nucleic acids (UA, RNA, and DNA) in the liver, heart, kidney, blood supernatants, and muscle homogenates of African sharptooth catfish ([ASC] Clarias gariepinus) exposed to varying bonny-light crude oil concentrations to understand the underlying cause of their delayed development as well as potential health and wellbeing. Three concentrations (20, 50, and 100 mg/L) of diluted whole bonny-light crude oil (DWC), water-soluble (WSF), and water-insoluble (WIF) fractions of bonny-light crude oil were used to grow ASC for 9 weeks at room temperature. Biochemical assessments revealed significant (at p < 0.05) elevations in heart LDH (48.57 ± 4.67 to 3011.34 ± 4.67 U/L) and blood G-6-PDH activities (54.86 ± 0.00 to 128 ± 18.29 mU/mL), GLU (0.22 ± 0.01 to 0.77 ± 0.01 mg/dL), TP (5.15 ± 0.14 to 22.33 ± 0.21 g/L), UA (0.29 ± 0.05 to 10.05 ± 0.27 mg/dL), as well as liver DNA (0.38 ± 0.02 to 2.33 ± 0.09 μg/mL) and RNA (12.52 ± 0.05 to 30.44 ± 0.02 μg/mL) levels for laboratory-grown ASC in DWC, WSF, WIF, and oil-impacted Ubeji river collected ASC relative to the control. Due to greater levels of cellular metabolic alterations in oil-impacted Ubeji River collected ASC, it is evident that bonny-light contamination levels in the river is greater than 100 mg/L. In conclusion, bonny-light crude oil is toxic to ASC and induces stress response. The ecological changes caused by bonny-light crude oil contamination may ultimately affect niche functioning and the development of organs in ASC.

Phytoremediation of Crude Oil Polluted Soil Using Dried Yam Peels (Discorea sp) as a Case Study in Niger Delta Environment of Southern Nigeria

This study aimed at enhancing the remediation of crude oil polluted soil using yam peels. 2kg of the soil samples were polluted crude oil at different concentrations ranging from 5%, 10% and 15%. There were three amended and un-amended samples each labeled A-F. The amended samples were A, C and E which contained the following respectively, 5% polluted soil + 150g yam peels, 10% polluted soil + 150g of yam peels and 15% polluted soil + 150g yam peels. The un-amended samples were B, D and F which were called the control samples with 5%, 10% and 15% concentration of crude pollutant. Parameters such as soil moisture content, total organic carbon, pH and total hydrocarbon content were analyzed before and after remediation. The result showed that yam peels enhanced remediation of the soil especially in treatment A. The reduction in Total Hydrocarbon Content was highest in the 5% crude oil polluted soil sample resulting 57.4% and least at 15% polluted control sample resulting 44.2%. The higher the concentration of crude oil in the soil the lower the percentage degraded. Yam peels which are agro waste can enhance biodegradation of crude oil in polluted soil and therefore can act as remediating agent.

Bioremediation of Contaminated Soil with Crude Oil Using New Genus and Species of Bacteria

In this study, the ability of bacteria presents in soils contaminated with crude oil to degrade petroleum hydrocarbons at the study sites (Al-Fatha and AL-Qayyarah) is investigated. Ten bacterial isolates are isolated from the soils of the study area, collected from different areas of Al-Fatha near the North Refineries in Salah-Din Governorate and AL-Qayyarah Refinery in Nineveh Governorate. These bacterial isolates show uneven growth in the mineral medium prepared with crude oil. Three new bacterial genera and two species are obtained, one of which belongs to the genus Bacillus and the other to the genus Exiguobacterium. The new bacterial isolates are recorded in the National Center for Biotechnology Information (NCBI) for the first time with the following numbers:(LC596402, LC596403&amp; LC596406) for the genus (AM-I-1, AM-I- 2, and AM-I-5), respectively and (LC596404, LC596405) for the species (AM-I-3 and AM-I-4), respectively. The results show the ability of the isolates (AM-I-1, AM-I-2, AM-I-3, AM-I-4, and AM-I-5) to consume Polyaromatic Hydrocarbons (PAHs) compounds in the mineral medium prepared with crude oil with different concentrations and degrees, temperatures and pH conditions. The optimum conditions are pH 7, temperature 40°C and 2% crude oil concentration with a period of 12 days. The bacteria (AM-I-3) has outperformed the rest of the bacterial isolates with a consumption of (PAHs) compounds of 86.5%, followed by bacterial isolates and their mixture with a consumption rate of (84.42%, 78.19%, and 75.20%) (AM-I-1, AM-I-4, &amp; mix of isolates), respectively.

High pressure micromechanical force method to assess the non-plugging potential of crude oils and the detection of asphaltene-hydrate mixed agglomerates

A hydrate prevention strategy taking advantage of crude oil that exhibit hydrate non-plugging tendency is a viable option in oilfield production conditions, or during transient operations. For that reason, it is important to accurately evaluate crude oils for their potential as non-plugging oils in a small-scale apparatus, such as a High-Pressure Micromechanical Force (HP-MMF) system, before continuing to large-scale testing. HP-MMF is an interfacial method that has been applied to measure gas hydrate interparticle cohesive force to gain insight into the hydrate agglomeration tendencies of crude oils. Herein, methane/ethane hydrate cohesive force measurements in the presence of small concentrations of crude oil were performed in the HP-MMF. Direct observations from the HP-MMF revealed, for the first time, the appearance of asphaltene precipitates that interact with the gas hydrate particles to produce an asphaltene-hydrate mixed agglomerate. A new HP-MMF method has been developed that enables representative sampling and evaluation of the effect of crude oil samples on the cohesive force between two gas hydrate particles in the HP-MMF. The method has been tested with two crude oils, where lower cohesive force results are demonstrated by the presence of small concentrations (<5 vol% in model oil) of Crude A and C compared to the baseline system of pure model oil. Hence, indicating the presence of natural anti-agglomerants (AAs) that contribute to the non-plugging behavior of these crude oils. These studies show that the HP-MMF is a convenient tool to assess the non-plugging potential of crude oils at realistic (high pressure, low temperature) conditions, requiring only small oil sample volumes. The HP-MMF method developed in this work is demonstrated to be a unique tool that can be utilized for the detection of asphaltene-hydrate mixed agglomerates. These new findings provide important insights for asphaltene precipitation in the presence of gas hydrates, that can create catastrophic agglomeration in the flowlines.

Evaluation of the molybdenum isotope system as a petroleum tracer: The Phosphoria petroleum system, western U.S.A.

The molybdenum (Mo) isotope composition of organic-rich mudrocks is used to infer paleo-ocean redox conditions but the potential of this isotope system as a petroleum tracer is uncertain. In this study, we measured the Mo isotope compositions of crude oils, asphaltene separates, and organic-rich source mudrocks (Meade Peak Member and Retort Member of the Permian Phosphoria Formation) for the Phosphoria petroleum system, western U.S.A. Crude oils from the Bighorn Basin have Mo concentrations of 0.01–0.39 μg/g that are significantly lower than Mo concentrations of 10–443 μg/g for the organic-rich mudrocks (2.4–16.6 wt% total organic carbon; TOC), suggesting inefficient transfer of Mo from source rock kerogen to oils. Asphaltene Mo concentrations are elevated (1.0–3.2 μg/g), indicating that asphaltene is an important host of Mo in the Phosphoria crude oils. However, statistically insignificant correlation between crude oil and asphaltene Mo concentrations as well as differences between the δ98Mo of some crude oils and their asphaltene separates (Δ98Moasphaltene–crude oil between −0.5‰ and +0.1‰) suggests other important hosts for Mo in the non-asphaltene fraction of the Phosphoria oils. The overall range of δ98Mo for fifteen Phosphoria crude oils and six asphaltene separates is 0.5–1.7‰ and 0.8–1.5‰, respectively. Crude oils unaltered by reservoir processes (biodegradation, water washing, thermochemical sulfate reduction) have δ98Mo of 1.1–1.4‰ whereas crude oils mildly affected by biodegradation and/or water washing span a wider range of δ98Mo (1.0–1.7‰). Five crude oils altered by thermochemical sulfate reduction (TSR), as indicated by higher δ34S, have lower δ98Mo (0.5–0.9‰), suggesting that TSR decreases the δ98Mo of crude oils via redox reactions and/or the introduction of external fluids containing isotopically light Mo into the oil reservoir. Biodegradation may cause variable δ98Mo in crude oils via kinetic isotope effects, microbial processes, or the recapture of isotopically distinctive Mo released from biodegraded oils elsewhere. A statistically significant inverse correlation between δ98Mo and δ34S for non-TSR altered oils may reflect a decrease in the δ98Mo of crude oils with increasing thermal maturity, perhaps associated with de-metalation reactions and/or formation of new organo-metal compounds. The δ98Mo of the unaltered crude oils falls within the range of δ98Mo for the Mo- and TOC-rich source rocks of the Retort and Meade Peake Members (1.0–2.0‰), suggesting the Mo isotope system has potential as an oil – source rock tracer. This application will have the most success in petroleum systems whose source rock(s) exhibit a narrow range of distinctive δ98Mo. Our study shows the Mo isotope system has promise as a petroleum tracer and potentially could be useful for studies on petroleum contamination in the environment.

THE ROLE OF FUNGI IN THE TREATMENT OF HYDROCARBON WASTE

This study aims to clarify the importance fungi, in treating soil pollution with hydrocarbon residues. The soil's physiological, physical, chemical properties, and biological diversity, are affected by the long-term existence of crude oil. The study showed that the fungi's natural presence or addition to the soil would change and decrease the concentrations of polycyclic hydrocarbons according to the different concentrations of crude oil. The most important isolates of hydrocarbon decomposers belong to Aspergillus spp and Penicillium spp.

Kinetics of Arab Light Crude Oil Degradation by Pseudomonas and Bacillus Strains

The biodegradation of crude oil is a consequence of the presence of a specific enzymatic system in the microorganisms selected: the alkane hydroxylase (AlkH). The enzymatic biodegradation has been described since 1994, when the enzyme was first isolated from P. putida (formerly P. oleovorans), but the kinetics of microbial degradation has been weakly considered. We studied and described in this work the kinetics of Arab Light biodegradation, a light crude oil used for gasoline production (46.4% C7–C12 n-alkanes), using two oleophilic strains (Bacillus licheniformis and Pseudomonas putida). Alkanes were extracted from aqueous solutions in the bioreactors by dichloromethane, with a high ratio aqueous:organic volumes (1:0.2 mL) for the amplification of the GC n-alkane signals, and GC spectra were monitored in time over 40 days. Petroleum emulsions were visualized using optical microscopy as a result of biosurfactant segregation, which is necessary for the enzymatic biodegradation of oil by microorganisms. Kinetic analysis in biodegradation of Arab Light (total petroleum hydrocarbons, TPH) exhibits first-order kinetics with 0.098 d−1 and 0.082 d−1 as kinetic coefficients for 8.6 g/L initial crude oil concentration (30 °C), which results in degradation rates of 843 mg/Ld and 705 mg/Ld in B. licheniformis and P. putida, respectively. These results can be applied for oil spill bioremediation, using these microorganisms with the objective of removing contamination by petroleum alkanes.

Application of 15N tracing and bioinformatics for estimating microbial-mediated nitrogen cycle processes in oil-contaminated soils

Crude oil pollution can profoundly alter the nitrogen (N) cycle in the soil. Here, a 30-day incubation with 15N tracer approach was performed to assess the impacts of crude oil concentrations (medium: 10,000 mg kg−1; heavy: 50,000 mg kg−1) on soil N cycling based on a numerical model. Results showed that crude oil pollution significantly increased the gross N-transformation rates, but the rates of oxidation of recalcitrant organic N, the immbolization of NO3− and the adsorption of NH4+ changed differently as a function of hydrocarbon concentrations. There was no significant difference of the oxidation rate of recalcitrant organic N between the medium and heavy oil-contaminated soils (medium: 0.1149 mmol N kg−1 d−1; heavy: 0.1299 mmol N kg−1 d−1), but the rates of NO3− immobilization (0.1135 mmol N kg−1 d−1) and NH4+ adsorption were the highest (0.1148 mmol N kg−1 d−1) in the moderately oil-contaminated soils than those in the heavy polluted soil (0.0849 mmol N kg−1 d−1 and 0.0034 mmol N kg−1 d−1, respectively). The NO3− immobilization rate was 2.5-fold higher than its reduction rate, indicating that NO3− immobilization played a more important role during the process of NO3− transformation. Microbial community structure analysis indicated that phyla of Actinobacteria and Ascomycota respectively promoted the immobilization of NO3− to recalcitrant organic N and the reduction of NO3− to NH4+. The genus of Aspergillus was related to net NH4+ production, and the genera of Penicillium and Acremonium were responsible for oxidation of recalcitrant organic N to NO3−.

Evaluation of biosurfactant production by Sporosarcina halophila and its application in crude oil remediation

Background: Biosurfactants are valuable microbial products that have significant applications in various industries. The advantages of these compounds are biodegradability, low toxicity, activity in difficult environmental conditions, and the ability to produce oil residues and compounds from the surface of seawater and soils contaminated with oil compounds. The aim of this study was to evaluate the ability of biosurfactants production by Sporosarcina halophila. Methods: For this purpose, to detect the production of biosurfactant by Sporosarcina halophila, quantitative and qualitative screening methods such as hemolysis, oil spreading test and emulsification index test were used. Finally, different concentrations of crude oil in the bacterial growth medium were used to see that this strain can decompose crude oil using biosurfactant production to continue its growth or not. Results: The results showed that this strain is able to produce biosurfactants in oil hemolysis and spreading test with emulsifying activity of more than 30%, indicating that this strain is a suitable strain for biosurfactant production. Also, this strain could grow in the presence of crude oil in its medium as only carbon resource by biosurfactant production. Conclusion: This study showed that the metabolites derived from Sporosarcina halophila strain have emulsifying properties and can be considered as a potent strain in the production of biosurfactants. Also, it was concluded that these biosurfactants are applicable for many different industrial or environmental fields such as bioremediation of crude oil from soil or water by Sporosarcina halophila strain.

Effective bioremediation of petroleum-contaminated saline soil using halotolerant Bacillus strains isolated from the Persian Gulf.

A consortium isolated from the Persian Gulf is evaluated for its ability to bioremediate petroleum-contaminated soils. The soil sample was collected from oil fields of South Western Iran. The crude oil concentrations were set to 1000-10,000 mg/kg, and the sodium chlorideconcentration was set to 0.5%, 1%, 1.5%, 2%, and 2.5%. Operational parameters including volume (2-20 ml) and soil moisture (25%, 50%, and 100%) were studied consecutively according to one factor at the time of experimental design. A total number of eight different isolates capable of degrading crude oil were isolated from hydrocarbon-contaminated sites (KL1-KL8). The removal efficiency of Total petroleom hydrocarbons (TPH) with an initial concentration of 1000 mg/kg for numbers of bacterial cells per gram soil of 2, 10, and 20 CFU/g was 20.9%, 45%, and 60%, respectively. The removal efficiency of TPHs (initial concentration of 1000 mg/kg) at the end of fifth week for salinity amounts of 0.5%, 1%, 1.5%, 2%, and 2.5% was 10.87%, 22.4%, 25.7%, 68.6%, and 60.5%, respectively. The TPHs biodegradation efficiencies at different soil/water ratios of 25%, 50%, and 100% (slurry) were 12%, 28.7%, and 60.8%, respectively. In sunflowers, there was no statistically significant difference in seed germination for different levels of soil pollution (p > 0.05). The results of the current work suggest that this process is a viable and efficient method for remediating contaminated sites. To enhance the removal results in real soil, a scale-up study should also be conducted.

Surface modified basalt membrane as a photothermal material for improved oily wastewater solar evaporation

ABSTRACT Oily wastewater is produced from many processes in petrochemical, food, pharmaceutical, mining, and metal industries. Proper management of oily wastewater discharges is required to mitigate their environmental impacts. Basalt fabric has been reported as being uniquely suitable for oily wastewater purification via solar evaporation due to its robust structure and surface chemistry. In this study, an efficient, low-cost, and scalable 3D photothermal evaporator was prepared by surface modification of basalt fabric with TiO2 nanoparticles for oily wastewater treatment and solar steam generation. The basalt membrane was coated with two types of TiO2 (Degussa P25 and nitrogen-doped TiO2) to enhance its hydrophilicity and photocatalytic properties important for fouling control. The basalt membranes were then tested for their impacts on water evaporation under various salinities and concentrations of gasoline constituents and crude oil. In pure water, the modified membrane system achieved an evaporation rate of 1.65 kg‧m−2‧h−1 under 1 sun irradiation, which is higher than the theoretical value of 1.47 kg‧m−2‧h−1 due to the 3D nature of the structure capable of harvesting energy from the environment. Crude oil significantly decreased the evaporation rate of the unmodified basalt membrane. However, the coating of TiO2 nanoparticles was found to ameliorate the fouling effect by increasing the membrane evaporation efficiency from 0.75 kg‧m−2‧h−1 to 1.42 kg‧m−2‧h−1 in a 2.0 g/L oily water composition. This technology is promising as a new approach to manage oily wastewater storage tanks and evaporation ponds in industry in addition to improving the efficiency of resource recovery.

Application of Microbial Degradation Technology in Oil Pollution Control

Oil pollution is still a problem that is very difficult to control. To this end, this study investigates the application effect of microbial degradation technology in oil pollution control. First, the degradation microbial strains and substrates were determined according to the type of microorganisms. Then, ultraviolet spectrophotometry was used to determine the concentration of crude oil in the culture medium. After that, the authors designed the flow chart of crude oil standard curve, extracted organic phase, determined the residual oil composition in the culture medium, and calculated the degradation rate of mixed bacteria to crude oil. By studying the degradation mechanism of aerobic bacteria, anaerobic bacteria, and fungi, the degradation products were confirmed and the treatment of oil pollution on the water surface was carried out. It can be seen from the experimental results that the microbial degradation technology is effective in solving the problem of oil pollution.

Bioremediation Potential of Selected Rhizosphere Fungi of Tridax Procumbens Linn. and Chromolaena odorata (L.) R.M. King &amp; H. Rob

Co-metabolism between plants and rhizosphere microbes is the mainstay of rhizoremediation of contaminated soils. The aim of the current study was to isolate and screen selected rhizosphere micro-fungi of two Asteraceae (Tridax procumbens and Chromolaena odorata) collected from the wild in University of Lagos, Akoka, Lagos State for bioremediation potential. Rhizosphere fungi were isolated, identified and evaluated for crude oil myco-remediation. The inhibitory effect of different concentrations of crude oil on mycelial growth of the most abundant fungi was determined with poisoned plate assay method. The most abundant and recurring fungi around C. odorata and T. procumbens were determined using the serial dilution and plating methods. Analysis of the rhizosphere soil of T. procumbens and C. odorata showed they were sandy loam type. C. odorata soil had higher moisture, organic carbon, and acid content than T. procumbens. Aspergillus flavus and Trichoderma harzianum were the most abundant and recurring fungi in C. odorata and T. procumbens, respectively. Thirty-nine micro-fungi belonging to twenty genera were isolated from the test plants’ rhizosphere. A. flavus and T. harzianum tolerated 2.50 to 10.00% crude oil contamination assessed with their mycelial growth inhibition reducing with time. A. flavus and T. harzianum caused a 68.45% and 86.71% reduction of crude oil contamination respectively, in a time dependent manner. The filamentous fungi ~A. flavus and T. harzianum can potentially be used to simultaneously ameliorate crude oil contaminated soils in conjunction with C. odorata and T. procumbens, respectively in the innovative technology termed rhizoremediation.

Capability of the Microalga Scenedesmus dimorphus for Biodegradation of Crude Oil Components: Biological Responses and Catabolic Intermediates

AbstractThe capability of Scenedesmus dimorphus for biodegradation of crude oil components is evaluated using biological and biochemical techniques. After exposure of the algal cells to different concentrations of crude oil for 21 day, growth parameters such as cell number as well as fresh and dry weights have increased at low concentrations of crude oil (up to 0.04%) in comparison with control samples. However, growth criteria have decreased in response to the increase in crude oil concentration (0.08%–1%). Similar trends are observed in the content of chlorophylls, carotenoids, flavonoids, anthocyanins, and phenols. Crude oil treatment induces the production of H2O2 and thiobarbituric acid reacting substances. Moreover, enhancing crude oil concentration results in increasing activities of superoxide dismutase, polyphenol oxidase, peroxidase, and lipoxygenase. In comparison, the activities of catalase, ascorbate peroxidase, and phenylalanine ammonia lyase increase at low concentrations (up to 0.02%) and then decrease. Using gas chromatography–mass spectrometry analysis several biodegradation intermediate compounds are recognized in the culture media over treatment time. Altogether, S. dimorphus shows considerable potential for biodegradation of crude oil components particularly at concentrations lower than 0.08%. Thus, this microalga can be used as a competent phytoplankton in removal of crude oil from contaminated water supplies.

Application of near infrared spectroscopy in sub-surface monitoring of petroleum contaminants in laboratory-prepared soils

ABSTRACT This study was conducted to determine the suitability of near-infrared (NIR) spectroscopy for subsurface monitoring of crude oil contaminants in different soil types under different moisture conditions. Calibration tests, carried out in both wet and dry soils, with crude oil contents 5–30% indicate an inverse relationship between spectra and oil content with R2 values ≥0.98 for dry soil mixtures. A derived index termed “Oil Index” was generated by calculating a spectral ratio between the main oil peak in the NIR region and a spectrally inactive part of the spectrum within the visible region. It was used in a series of experiments designed to test whether NIR probes could yield useful information about the movement of oil through different soils. Synthetic crude oil was dropped into a series of soil samples of different particle size distribution and moisture content. Analyses of the 3D distribution of values of the Oil Index demonstrate that it is possible to estimate and map synthetic crude oil concentration in the subsurface of the soil samples. Results showed that while the Oil Index provided a reasonable estimation for oil concentration in dry samples, this was not the case for wet samples, although the Index was useful in understanding the pattern of movement of oil contaminant in wet soils. The work indicates that this technique may enhance field investigation of oil contamination, providing an accurate in-field technique.

Sound Productivity of Spiny Lobster Panulirus homarus (Linnaeus, 1758) due to Crude Oil Contamination

Anthropogenic activities have the potential to put pressure on the marine environment. Crude oil was one of the pressure that give rise to any response of the aquatic organism, such as sound. This study aimed to analyze the sound productivity of spiny lobster Panulirus homarus (Linnaeus, 1758) in waters contaminated with crude oil. Observation of lobster sound was carried out on a laboratory scale using the passive acoustic method. A hydrophone and Closed Circuit Television (CCTV) camera coupled with a decoder and personal computer used to record the movements and sounds of P. homarus during the treatment of crude oil at concentrations 1; 5; 10 and 100 mgL-1. The result showed that crude oil contamination in water was impacted the sound productivity of P. homarus. In the low concentration of crude oil (1 - 5 mgL-1), P. homarus was responded with more sound produced. Afterwar, until concentration off 10 mgL-1, the response of P homarus showed different between individuals. In the 100 mgL-1 concentration, the sound productivity of all P. homarus was decreased. Based on this study, we concluded that the sound of P. homarus has the potential as an indicator of water pollution.Keywords: Panulirus houmarus, crude oil, fish sound

Kinetic modeling and half-life study on bioremediation of crude oil dispersed by palm bunch enhanced stimulant

The work focused on the kinetic modeling and half-life study of the bioremediation of crude oil dispersed by palm bunch enhanced stimulant. In this study, three bioremediation processes, namely; palm bunch enhanced stimulant (PES) stimulation, modified crude oil dispersant (MCD) stimulation and natural attenuated stimulation (NAS), were carried out at various petroleum hydrocarbon concentrations in polluted water media. Bacterial culture, isolations, and identification were carried out to isolate and identify the bacterial involved in the bioremediation. The process kinetics and half-life were investigated. Characterization of PES showed that PES has an appreciable quantity of potassium, phosphate, nitrate, sulphate and calcium required for cell growth and development. Bacillus pumilus, Micrococcus roseus, Micrococcus luteus, and Pseudomonas putida were the bacteria isolated from the culture. The optimum bio-stimulation efficiency of PES occurred on day 6, with BE values of 93.23%. The degradation rate constants for the PES enhanced bioremediation process decreased as the crude oil initial concentration increased from 100 to 300 mg/L. The result showed that the degradation rate constants for PES stimulated remediation were 0.11, 0.04 and 0.03 at 100, 200 and 300 mg/L of crude oil, respectively. The MCD stimulated remediation showed degradation rate constants of 0.04, 0.03 and 0.018, at crude oil concentrations of 100, 200, and 300 mg/L, respectively. The trend was the same for NAS. The longest half-life for 100 mg/L of crude oil was achieved after 79.67 days during the NAS stimulation. The results obtained from this report showed tremendous improvement to the degradation of crude oil due to the presence of PES. The degradation process was adequately described by the first order kinetic model and showed the effectiveness of PES in the remediation process. Therefore, the data obtained in this study could be applied in the design of a bioremediation system for potential application to remediation of crude oil polluted water.