Biodegradation Of Petroleum Hydrocarbons Research Articles

Responses of hydrochemical parameters, community structures, and microbial activities to the natural biodegradation of petroleum hydrocarbons in a groundwater–soil environment

Responses of hydrochemical parameters, bacterial community structures, and microbial activities during the natural biodegradation of hydrocarbons leaking from a crude oil pipeline at a site in northeastern China were studied using the hydrochemical method, the polymerase chain reaction amplification of 16S rDNA genes, and denaturing gradient gel electrophoresis (DGGE).The concentrations of PHs and the main physicochemical characteristics (Eh and pH) were increased gradually at longitudinal ZK1–ZK3–ZK6 section in June 2010, suggesting that the degree of biodegradation decreased gradually from the pollutant source to downstream. The electron acceptor (SO42−) participated in biodegradation process responds identical trend to the degree of biodegradation at the same section while the biodegradation reduction products (Fe2+, Mn2+, and HCO3−) respond to it in opposite trend. The concentrations of Fe2+, Mn2+, and SO42− at wells ZK1 and ZK3 indicate that sulfate-reducing biodegradation was the dominant process experienced at contaminated sites rather than iron–manganese reduction processes. The dynamic changes of hydrochemical parameters suggest that the degree of biodegradation would be intensified at the center of pollutant plume and iron–manganese reduction processes experienced earlier than sulfate-reducing biodegradation. The community diversities and microbial activities in different soil depths were responded to PHs, but the relationship is not simply linear. The community diversities and microbial activities increased significantly with rise in PH concentration of soil until about 20 mg/kg and then peaked off sharply, suggesting that community succession would be occurred in microhabitat when the PH concentration in soil exceeds 20 mg/kg. The major DGGE bands found in the soil samples were sequenced. One sequence affiliated with γ-Proteobacteria showed high similarities to uncultured bacteria which had been found in offshore oil pollution environment. These bacterial species were found to have similar petroleum degradation functions to the bacteria at the sites studied here.

Treatment of soil co-contaminated with inorganics and petroleum hydrocarbons using silica: Implications for remediation in cold regions

Successful remediation of contaminated land in cold regions is challenged by freeze-thaw cycling, slow rates of natural hydrocarbon attenuation, extreme weather and financial and logistical constraints. At sites co-contaminated with metals and petroleum hydrocarbons, microbial activity is suppressed and biodegradation of petroleum hydrocarbons is also slowed. This study assesses the performance of eight silica treatments for immobilising inorganics (Al, Cr, Fe, Ni, Cu, Zn, As, Cd and Pb) and encapsulating petroleum hydrocarbons (a winterised diesel) in co-contaminated soil at 2°C. Treatments containing orthophosphoric acid immobilised Cu, Zn, Cd and Pb, but mobilised As. The formation of hydroxypyromorphite, sodium aluminosilicates and calcium bearing minerals were observed following treatment, demonstrating the potential for successful immobilisation of inorganics using silica treatments. Silica treatments were less effective at reducing total extractable concentrations of petroleum hydrocarbons in soil, indicating that further research is required to optimise treatment performance in soil co-contaminated with inorganics and petroleum hydrocarbons.

Petroleum biodegradation capacity of bacteria and fungi isolated from petroleum-contaminated soil

We investigated the potential for petroleum hydrocarbon biodegradation by 95 bacterial and 160 fungal strains isolated from a former petrochemical plant. We tested whether soil origin, culture media type, and strain taxonomy influenced the degradation of added petroleum hydrocarbon compounds. Preliminary screening was based on two colorimetric tests using 2,6-dichlorophenolindophenol and p-iodonitrotetrazolium indicators, to assess microbial strain tolerance to crude oil. Top-performing strains in these screening assays were then assessed for their ability to mineralize a mixture of four polycyclic aromatic hydrocarbons (PAH) for 49 days, using GC-MS quantification. The aerobic activity of these candidate strains was also assessed by respirometry over the first 24 days of incubation. On average, PAH degradation by microbial isolates from soil that was lightly, moderately, and highly contaminated with petroleum was equally efficient, and the type of culture medium used did not significantly impact mean biodegradation. Phylogenetic affiliation had a strong and significant effect on PAH biodegradation. Fungal isolates belonging to the group Sordariomycetes, and bacterial isolates belonging to the groups Actinobacteria, Betaproteobacteria, and Gammaproteobacteria showed high potential for PAH degradation. Three of the strains tested by GC-MS, Rhodococcus sp., Trichoderma tomentosum, and Fusarium oxysporum, significantly degraded all four PAH compounds in the mixture compared to the control.

The accelerated enzymatic biodegradation and COD removal of petroleum hydrocarbons in the SCR using active bacterial biomass capable of in-situ generating peroxidase and biosurfactants

The enzyme-accelerated biodegradation of total petroleum hydrocarbons (TPH) was investigated in a sequencing continuous-inflow reactor (SCR) at different operational parameters of H2O2/TPH ratio, initial TPH concentration and hydraulic retention time (HRT). The optimum H2O2/TPH mass ratio was determined to be 0.35 at which the complete TPH removal of inlet TPH concentrations up to 4g/L at HRT of 24h, corresponding to the loading rate of 4kgTPH/m3.d, was attained. The average COD removal efficiency at this loading rate was 96.7%. With increasing the inlet TPH concentration from 1 to 2.5g/L, the biomass bacterial activity as dehydrogenase activity (DHA) increased from 7.5 to 27.1μgTF/gbiomass.d and remained almost unchanged with further increase of TPH concentration. The peroxidase activity (PA) remained high between 382 and 410U/gbiomass. In addition, the complete removal of 1g/L TPH (88.7% COD removal) was observed at HRT of as small as 4h (corresponding to the loading rate of 6kgTPH/m3.d) under optimum H2O2/TPH mass ratio. With the decrease of HRT from 24h to 4h at the constant TPH concentration of 1g/L the value of DHA remained between 24.4 and 28.4μgTF/gbiomass.d while the PA value increased from 287.9 to 394.4U/gbiomass. Total production of biosurfactants was 131mg/L (38mg/L rhamnolipid and 93mg/L surfactin) when the SCR was operated at TPH loading rate of 6kg/m3.d.Finally, the enhanced enzymatic biodegradation of TPH by using diverse microbial consortia capable of in-situ production of peroxidase and biosurfactant generation in the SCR is a very efficient and promising technique for accelerated biodegradation and COD removal of petroleum hydrocarbons.

Effects of Freeze–Thaw Phenomena on Controlled Nutrient Release: Application to Bioremediation

Cold region soils are often devoid of sufficient nutrients essential for timely bioremediation of petroleum hydrocarbon contaminants. While materials that release nutrients in a controlled manner have been shown to stimulate biodegradation over extended time periods, the physical and chemical response of these materials to repetitive freeze–thaw stresses typical of cold regions remains poorly understood. This study reports the performance of four controlled release materials in water (Osmocote™, Nutricote™, Polyon™, Zeopro™) exposed to freeze–thaw cycling or control temperature of 4°C. Additionally Zeopro™‐activated carbon mixtures are investigated for application to permeable reactive barriers. Osmocote™ experienced higher nutrient release under control conditions compared with samples exposed to freeze–thaw after 20 days. Nutrient release from Nutricote™ and Polyon™ was similar under freeze–thaw and control conditions. Zeopro™ delivered low nutrient concentrations into solution in both freeze–thaw and control samples with calcium phosphate dissolution accelerated in the presence of activated carbon. Osmocote™, Nutricote™ and Polyon™ revealed strong resistance to breakdown under freeze–thaw. Zeopro™ experienced only partial disintegration, while significant break‐up of activated carbon occurred under freeze–thaw. A physical and chemical understanding of the response of multiple fertilisers can guide the selection of materials for biostimulation and biodegradation of petroleum hydrocarbons in environments exposed to freeze–thaw cycling.

Exploring the potential of halophilic bacteria from oil terminal environments for biosurfactant production and hydrocarbon degradation under high-salinity conditions

The wastewater from oil production can be exceptionally saline and contain a complex mixture of hydrocarbons, many of which are highly toxic. This study aimed to identify and characterize 141 halophilic bacteria isolated from production water and activated sludge from Marine Terminal Almirante Barroso (Brazil) and evaluate their potential for biosurfactant production and biodegradation of distinct petroleum hydrocarbons. Sequencing and phylogenetic analysis of the 16S rRNA gene revealed that the halophilic bacteria retrieved are distributed among 20 genera and four phyla (Proteobacteria, Firmicutes, Actinobacteria and Flavobacteria). RAPD fingerprinting was used to differentiate isolates at the infra-specific level, revealing 79 different genetic profiles. GC-MS analysis carried out with eight strains confirmed their ability to efficiently degrade alkanes and aromatic compounds under halophilic conditions, with preference for aromatic degradation. Eleven strains showed significant ability for reduction of the surface tension (from 72 to 40 mN/m) and for emulsification (up to 71%) of four different types of oils (mineral, soybean, diesel and kerosene). Results gathered in this study demonstrate a high taxonomic and genetic diversity of the halophilic bacterial strains isolated from the oil terminal samples and an outstanding potential for further use in biotechnological processes such as biosurfactant production or bioremediation.

Influence of humic acid on biodegradation of petroleum hydrocarbons in oil-contaminated soils

ABSTRACTThis study evaluated the use of humic acid (HA) to enhance biodegradation of petroleum hydrocarbons in a soil contaminated with diesel oil at an initial total petroleum hydrocarbons (TPH) concentration of 5000 mg kg−1 soil (0.5%). The HA was characterized using Fourier transform infrared (FTIR) spectroscopy. Six pans of 0.5% diesel oil-contaminated soil were prepared—three pans were supplemented with three rates of HA (10, 20, and 30g HA kg−1 soil) and urea, one pan was supplemented with only urea, another pan was without any amendment (control), and the sixth pan was supplemented with a diesel-oil-contaminated soil that was steam-sterilized (nonbiologically active soil) . These pans were used to investigate the effects of HA on the biodegradation of TPHs and the population of hydrocarbon-utilizing bacteria (HUB) by measuring residual concentration of TPH and microbial count, respectively, during a 75-day incubation experiment. At the end of the incubation, the lowest reduction in TPH concentration was observed in the sterilized soil. The TPH in HA amended pans had reduced from 55.55 to 80.70%, while other biologically active soils recorded reductions between 21.39 and 32.59%. The pan containing only nutrient recorded lower concentration of TPH (32.59%) compared to the control (21.39%). The HA-amended pans also recorded highest count of HUB that ranged between 3.6 × 106 and 11.5 × 106 cfu g−1. The pan containing only urea recorded HUB count of 5.9 × 106 cfu g−1, while the control had HUB count of 2.2 × 106 cfu g−1. The results of this study showed that HAs enhanced biodegradation of petroleum hydrocarbons and also stimulated the proliferation of soil bacteria.

Effects of bioaugmentation on sorption and desorption of benzene, 1,3,5-trimethylbenzene and naphthalene in freshly-spiked and historically-contaminated sediments

This work investigated the frequently observed “rebounds” of contaminants of concern in groundwater systems. Specifically, influences of bioaugmented microorganisms on the sorption and desorption of representative petroleum constituents [benzene, 1,3,5-trimethylbenzene and naphthalene (BTN)] were studied in freshly-spiked and historically–contaminated sediments. Capable microorganisms were enriched and supplemented to contaminated sediments to enhance biodegradation of petroleum hydrocarbons. In freshly-spiked sediments, when petroleum-degrading microorganisms were added, concentrations of dissolved petroleum constituents appeared to increase initially, and 12.4, 14.0 and 20.0 mg/kg of benzene, 1,3,5-trimethylbenzene and naphthalene, respectively desorbed from the sediments into the water phase. In the historically-contaminated sediments, the augmentation of petroleum-degrading microorganisms led to the desorption of 0.023–0.059, 0009–0.016, and 1.731–2.763 mg/L of previously sequestrated BTN into the water phase, and also triggered the desorption of 0.051–0.223, −0.133–2.630, and 2.324–1.200 mg/kg of previously sequestrated BTN as the methanol extraction quantity. The mechanisms of the enhanced desorption at the presence of microbes remain to be determined; however, we presumed that microbially produced constituents such as biosurfactants and cell mass could have attributed to the partition of petroleum compounds from the sediments. Findings from this study may partially explain “rebounds” of certain petroleum constituents into the groundwater during in situ bioremediation practice, although such immediate rebounds sometimes are weak, and the desorbed constituents can be eventually biodegraded under proper biogeochemical conditions.

Bioremediation of heavily hydrocarbon-contaminated drilling wastes by composting

Oil-based drilling cuttings comprise a large and hazardous waste stream generated by oil and gas wells drilling operations. Oil-based cuttings are muddy materials with high contents of salts and hydrocarbons. Composting strategies have shown to be effective in the biodegradation of petroleum hydrocarbons, and it offers numerous advantages in comparison with other bioremediation methods. In order to assess the effectiveness of drilling cuttings bioremediation by composting with food and garden wastes, an experiment was conducted in 60-L reactors for 151 days. Four treatments were carried out: only oil-based cuttings, two proportions (in a volume basis) of organic wastes to drilling cuttings (33 and 75 %) and only organic wastes (as a traditional composting reference), with pine-tree woodchips as bulking agent. High degradation percentages of total hydrocarbons (≈82 %), n-alkanes (≈96 %) and the 16 USEPA-listed polycyclic aromatic hydrocarbons (≈93 %) were reached in the treatment with 75 % of organic wastes, and applying 33 % of organic wastes was not more effective than not applying organic wastes for the drilling cuttings hydrocarbons biodegradation. Furthermore, in the treatment with 75 % of organic wastes, alkanes half-life and polycyclic aromatic hydrocarbons half-life were about 10 times and four times lower, respectively, than those in the treatment with 33 % of organic wastes. Possibly, lower hydrocarbons and salts initial concentrations (i.e., lower toxicity), higher microbial counts, adequate nutrient proportions and water content supported a high biological activity with a consequent elevated biodegradation rate in the treatment with 75 % of organic wastes.

Geochemistry of Dissolved Organic Matter in a Spatially Highly Resolved Groundwater Petroleum Hydrocarbon Plume Cross-Section.

At numerous groundwater sites worldwide, natural dissolved organic matter (DOM) is quantitatively complemented with petroleum hydrocarbons. To date, research has been focused almost exclusively on the contaminants, but detailed insights of the interaction of contaminant biodegradation, dominant redox processes, and interactions with natural DOM are missing. This study linked on-site high resolution spatial sampling of groundwater with high resolution molecular characterization of DOM and its relation to groundwater geochemistry across a petroleum hydrocarbon plume cross-section. Electrospray- and atmospheric pressure photoionization (ESI, APPI) ultrahigh resolution mass spectrometry (FT-ICR-MS) revealed a strong interaction between DOM and reactive sulfur species linked to microbial sulfate reduction, i.e., the key redox process involved in contaminant biodegradation. Excitation emission matrix (EEM) fluorescence spectroscopy in combination with Parallel Factor Analysis (PARAFAC) modeling attributed DOM samples to specific contamination traits. Nuclear magnetic resonance (NMR) spectroscopy evaluated the aromatic compounds and their degradation products in samples influenced by the petroleum contamination and its biodegradation. Our orthogonal high resolution analytical approach enabled a comprehensive molecular level understanding of the DOM with respect to in situ petroleum hydrocarbon biodegradation and microbial sulfate reduction. The role of natural DOM as potential cosubstrate and detoxification reactant may improve future bioremediation strategies.

The performance of ammonium exchanged zeolite for the biodegradation of petroleum hydrocarbons migrating in soil water

Nitrogen deficiency has been identified as the main inhibiting factor for biodegradation of petroleum hydrocarbons in low nutrient environments. This study examines the performance of ammonium exchanged zeolite to enhance biodegradation of petroleum hydrocarbons migrating in soil water within laboratory scale flow cells. Biofilm formation and biodegradation were accelerated by the exchange of cations in soil water with ammonium in the pores of the exchanged zeolite when compared with natural zeolite flow cells. These results have implications for sequenced permeable reactive barrier design and the longevity of media performance within such barriers at petroleum hydrocarbon contaminated sites deficient in essential soil nutrients.

The peroxidase-mediated biodegradation of petroleum hydrocarbons in a H2O2-induced SBR using in-situ production of peroxidase: Biodegradation experiments and bacterial identification

A bacterial peroxidase-mediated oxidizing process was developed for biodegrading total petroleum hydrocarbons (TPH) in a sequencing batch reactor (SBR). Almost complete biodegradation (>99%) of high TPH concentrations (4g/L) was attained in the bioreactor with a low amount (0.6mM) of H2O2 at a reaction time of 22h. A specific TPH biodegradation rate as high as 44.3mgTPH/gbiomass×h was obtained with this process. The reaction times required for complete biodegradation of TPH concentrations of 1, 2, 3, and 4g/L were 21, 22, 28, and 30h, respectively. The catalytic activity of hydrocarbon catalyzing peroxidase was determined to be 1.48U/mL biomass. The biodegradation of TPH in seawater was similar to that in fresh media (no salt). A mixture of bacteria capable of peroxidase synthesis and hydrocarbon biodegradation including Pseudomonas spp. and Bacillus spp. were identified in the bioreactor. The GC/MS analysis of the effluent indicated that all classes of hydrocarbons could be well-degraded in the H2O2-induced SBR. Accordingly, the peroxidase-mediated process is a promising method for efficiently biodegrading concentrated TPH-laden saline wastewater.

Anoxic biodegradation of petroleum hydrocarbons in saline media using denitrifier biogranules

The total petroleum hydrocarbons (TPH) biodegradation was examined using biogranules at different initial TPH concentration and contact time under anoxic condition in saline media. The circular compact biogranules having the average diameter between 2 and 3mm were composed of a dense population of Bacillus spp. capable of biodegrading TPH under anoxic condition in saline media were formed in first step of the study. The biogranules could biodegrade over 99% of the TPH at initial concentration up to 2g/L at the contact time of 22h under anoxic condition in saline media. The maximum TPH biodegradation rate of 2.6 gTPH/gbiomass.d could be obtained at initial TPH concentration of 10g/L. Accordingly, the anoxic biogranulation is a possible and promising technique for high-rate biodegradation of petroleum hydrocarbons in saline media.

Ozone enhances biodegradability of heavy hydrocarbons in soil

The molecular complexity and the low solubility of petroleum hydrocarbon residuals in weathered soil hinder bioremediation as a clean-up strategy. Pretreatment with advanced oxidation, such as with ozone gas (O3), is a means to transform recalcitrant organics to more biodegradable forms. The efficacy of gas-phase ozone for enhancing the biodegradability of heavy residual petroleum hydrocarbons in weathered soil was tested. Ozonating soil containing ∼1% (w/w) residual petroleum hydrocarbons with a dose of 6 kg ozone/kg initial total petroleum hydrocarbons (TPHs) achieved nearly 50% TPH reduction, simultaneous with a >20-fold increase in soluble chemical oxygen demand, but with a ≤12% loss of total organic carbon. TPH molecules were converted to partly oxidised products, ten of which were identified as n-monocarboxylic acids, which were readily biodegraded, and ozonation resulted in a fourfold increase in 5-d biochemical oxygen demand (BOD5). BOD5 results after ozonation were the same with or without a microbial seed, which suggests that bioaugmentation is likely not necessary after ozonation. Deoxyribonucleic acid sequencing over the time course of the BOD5 tests showed increased diversity and changes in predominant genera, both of which underscore that ozonation made the heavy hydrocarbons readily biodegradable for soil bacteria.

Changes in Bacterial Populations During Bioremediation of Soil Contaminated with Petroleum Hydrocarbons

Using an indoor microcosm assay, we analyzed the biodegradation of total petroleum hydrocarbons (TPHs) by autochthonous bacterial populations in mining soil in the presence of a surfactant (Tween 80). The kinetic behavior of TPH biodegradation involved fast and slow stages. Initially, heterotrophic and hydrocarbonoclastic bacteria increased in abundance by an order of magnitude, but both groups decreased to close to their initial population sizes by the end of experiment. The most efficient final biodegradation (61.5 %) was achieved using soil with 0.5 % added surfactant. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) were used to analyze changes in the bacterial community structure. During the fast biodegradation phase, bacterial species richness as indicated by DGGE profiles was reduced after long periods of TPH biodegradation with exposure to Tween 80. The distribution of families was modified, but no particular pattern could be identified. The main bacterial genera were Acinetobacter, Pedomicrobium, Halomonas, Rhizobium, Cryobacterium, Pseudomonas, Lysobacter, Thermomonas, and Stenotrophomonas. Acinetobacter exhibited the highest species richness and was the most abundant and persistent genus, followed by Pedomicrobium and Rhizobium. Decreasing TPH biodegradation can be attributed to a reduction in the microbial population and the disappearance of most of the initial bacterial genera. The correlation between TPH biodegradation and microbial population dynamics helps explain long bioremediation times and can facilitate actions for increasing bioremediation efficiency.

Potential biodegradation of crude petroleum oil by newly isolated halotolerant microbial strains from polluted Red Sea area

Two microbial isolates from oil polluted Red Sea water in Egypt, designated as RS-Y1 and RS-F3, were found capable of degrading Belayim mix (BX) crude oil. Strains RS-Y1 and RS-F3 were assigned to the genera Lipomyces tetrasporus and Paecilomyces variotii based on their morphological and physiological characteristics. Both isolates were compared for the biodegradation of crude petroleum-oil hydrocarbons in basal salt medium supplemented with 5% (w/v) of BX-crude oil. Gas chromatography profile showed that the biodegradation of total petroleum hydrocarbons (TPHs) inoculated with L. tetrasporus (68.3%) and P. variotii (58.15%) along with their consortium (66%) significantly reduced TPHs levels as compared to the control after 30days. L. tetrasporus (44.5%) was more effective than P. variotii strain (32.89%) in reducing the unresolved complex mixtures (UCM) content from the medium. Both isolates exhibited a strong growth over a wide range of salinity (5–45g/L NaCl).

Humic Compounds in Treatment of Oil Contaminated Environments

The study considers main areas of use of humic substances — main matrix of organic matter in soil and water — in environment protection technologies. Humic compounds are proved to be the most widely used in bio- and phytoremediation of oil contaminated soils as the boosters of microorganism vitality and plant growth, as well as the improvers (ameliorants) of crude oil- and oil product contaminated soils promoting biodegradation of petroleum hydrocarbons. But the variety of raw material sources and humate production methods leading to high variability of properties, and absence of scientific approaches to their use result in contradictory appraisals of their performance. The conclusion is made to necessitate systematic research on processes of decontamination of petroleum hydrocarbons by humic substances and to develop for the selection criteria of humic substances to be used in cleaning technologies.

A quantum cascade laser infrared spectrometer for CO2 stable isotope analysis: Field implementation at a hydrocarbon contaminated site under bio-remediation

Real-time methods to monitor stable isotope ratios of CO2 are needed to identify biogeochemical origins of CO2 emissions from the soil–air interface. An isotope ratio infra-red spectrometer (IRIS) has been developed to measure CO2 mixing ratio with δ13C isotopic signature, in addition to mixing ratios of other greenhouse gases (CH4, N2O). The original aspects of the instrument as well as its precision and accuracy for the determination of the isotopic signature δ13C of CO2 are discussed. A first application to biodegradation of hydrocarbons is presented, tested on a hydrocarbon contaminated site under aerobic bio-treatment. CO2 flux measurements using closed chamber method is combined with the determination of the isotopic signature δ13C of the CO2 emission to propose a non-intrusive method to monitor in situ biodegradation of hydrocarbons. In the contaminated area, high CO2 emissions have been measured with an isotopic signature δ13C suggesting that CO2 comes from petroleum hydrocarbon biodegradation. This first field implementation shows that rapid and accurate measurement of isotopic signature of CO2 emissions is particularly useful in assessing the contribution of contaminant degradation to the measured CO2 efflux and is promising as a monitoring tool for aerobic bio-treatment.

Fate and reactions of methane during biodegradation in an aquifer contaminated with petroleum hydrocarbons in Northeast China

Biodegradation is well known as the most effective and important process in monitored natural attenuation (MNA). Previous studies at a crude oil spill site in Northeast China have documented the progress of oil biodegradation by analyzing geochemical indicators. However, without evidence about the behavior of methane (CH4), methanogenesis was only speculated to be occurring at the source area of the site. In this study, CH4 content, radiocarbon, and stable carbon isotopes of CH4 were analyzed to confirm the occurrence of methanogenesis during the biodegradation of petroleum hydrocarbons (PHCs) and to infer the fate of CH4. The results show that CH4 concentrations were higher in the pollution source than in the intermediate zone and in the fringes of the pollution plume, and they decreased gradually along the groundwater flow path. The 13C of CH4 and CO2 in the groundwater were in the ranges of the groundwater in other sites. However, in the pollution plume, the 13C of CH4 was more depleted than those in other places and the δ13C of CH4 was increasing in the groundwater flow direction. Confirmed by the presence of δ13C of dissolved inorganic carbon (DIC) and 13C Rayleigh fractionation modeling during CH4 reactions, we found that the PHC methanogenesis mainly occurred in the pollution source, while methane oxidation occurred along the downgradient of the plume. Percentage of modern carbon (pMC) data confirms that approximately 29% of the CO2 found in pollution source groundwater is derived from petroleum sources.

Biodegradation of Total Petroleum Hydrocarbon by a Consortium of Cyanobacteria Isolated from Crude Oil Polluted Brackish Waters of Bodo Creeks in Ogoniland, Rivers State

Biodegradation of Total Petroleum Hydrocarbon by a Consortium of Cyanobacteria Isolated from Crude Oil Polluted Brackish Waters of Bodo Creeks in Ogoniland, Rivers State