Levels Of Biodegradation Research Articles

Nanotechnology Applications in Systhesis Of Bioplastic

The plastic industry is often plagued with the inability to find an optimal balance between mechanical properties, cost of production and acceptable level of biodegradability of plastics. As a result of these problems, several methods of synthesis are sought after in a bid to produce competitive biodegradable effective materials which can be applied in various industries. This paper focuses on procedures to enhance the production of plastics; through agricultural waste and applying nanotechnology for better enhanced plastic products.

Bioaugmentation of Native Fungi, an Efficient Strategy for the Bioremediation of an Aged Industrially Polluted Soil With Heavy Hydrocarbons.

The concurrence of structurally complex petroleum-associated contaminants at relatively high concentrations, with diverse climatic conditions and textural soil characteristics, hinders conventional bioremediation processes. Recalcitrant compounds such as high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) and heavy alkanes commonly remain after standard soil bioremediation at concentrations above regulatory limits. The present study assessed the potential of native fungal bioaugmentation as a strategy to promote the bioremediation of an aged industrially polluted soil enriched with heavy hydrocarbon fractions. Microcosms assays were performed by means of biostimulation and bioaugmentation, by inoculating a defined consortium of six potentially hydrocarbonoclastic fungi belonging to the genera Penicillium, Ulocladium, Aspergillus, and Fusarium, which were isolated previously from the polluted soil. The biodegradation performance of fungal bioaugmentation was compared with soil biostimulation (water and nutrient addition) and with untreated soil as a control. Fungal bioaugmentation resulted in a higher biodegradation of total petroleum hydrocarbons (TPH) and of HMW-PAHs than with biostimulation. TPH (C14-C35) decreased by a 39.90 ± 1.99% in bioaugmented microcosms vs. a 24.17 ± 1.31% in biostimulated microcosms. As for the effect of fungal bioaugmentation on HMW-PAHs, the 5-ringed benzo(a)fluoranthene and benzo(a)pyrene were reduced by a 36% and 46%, respectively, while the 6-ringed benzoperylene decreased by a 28%, after 120 days of treatment. Biostimulated microcosm exhibited a significantly lower reduction of 5- and 6-ringed PAHs (8% and 5% respectively). Higher TPH and HMW-PAHs biodegradation levels in bioaugmented microcosms were also associated to a significant decrease in acute ecotoxicity (EC50) by Vibrio fischeri bioluminiscence inhibition assays. Molecular profiling and counting of viable hydrocarbon-degrading bacteria from soil microcosms revealed that fungal bioaugmentation promoted the growth of autochthonous active hydrocarbon-degrading bacteria. The implementation of such an approach to enhance hydrocarbon biodegradation should be considered as a novel bioremediation strategy for the treatment of the most recalcitrant and highly genotoxic hydrocarbons in aged industrially polluted soils.

Selective Removal of Toxic Ions from Water/Wastewater: Using a Novel Surfactant

Pollution of drinking water by toxic heavy-metal ions is a matter of concern worldwide. These ions occur naturally, and also from environmental spills, radioactive wastes and other industrial waste. Arsenic and lead are typical examples. A novel green surfactant, purpose designed, and environmentally friendly is shown to be extremely effective and specific for heavy metal ion removal. This is a considerable step forward on previous technologies. Surfactants have been used universally to remove organic and inorganic contaminants from water. But little selectivity has been achieved. After usage, the residual surfactants are discharged into surface waters or sewage systems. This causes environmental pollution. In this review, three surfactants from different classes (novel green surfactant, synthetic chemical surfactant and biosurfactant) are compared in terms of their efficiency in flotation, removal of different heavy-metal ions, biodegradability, and toxicity level, including their advantages and disadvantages.

A comprehensive review of the Fenton-based approaches focusing on landfill leachate treatment

Landfilling is the most commonly adopted method for a large quantity of waste disposal. But, the main concern related to landfills is the generation of leachate. The leachate is high strength wastewater that is usually characterized by the presence of high molecular recalcitrant organics. Several conventional methods are adopted for leachate treatment. However, these methods are only suitable for young leachate, having high biodegradability and low toxicity levels. The mature and stabilized leachate needs advanced technologies for its effective treatment. Advanced oxidation processes (AOPs) are very suitable for such complex wastewater treatment as reported in the literature. After going through the literature survey, it can be concluded that Fenton-based approaches are effective for the treatment of various high/low strength wastewaters treatment. The applications of the Fenton-based approaches are widely adopted and well recognized due to their simplicity, cost-effectiveness, and reliability for the reduction of high chemical oxygen demand (COD) as reported in several studies. Besides, the process is relatively economical due to fewer chemical, non-sophisticated instruments, and low energy requirements. In this review, the conventional and advanced Fenton' s approaches are explained with their detailed reaction mechanisms and applications for landfill leachate treatment. The effect of influencing factors like pH, the dosage of chemicals, nature of reaction matrix, and reagent ratio on the treatment efficiencies are also emphasized. Furthermore, the discussion regarding the reduction of chemical oxygen demand (COD) and color, increase in biodegradability, removal of humic acids from leachate, combined processes, and the pre/post-treatment options are highlighted. The scope of future studies is summarized to attain sustainable solutions for restrictions associated with these methods for effective leachate treatment.

Biodegradation of low-density polyethylene (LDPE) using the mixed culture of Aspergillus carbonarius and A. fumigates

Low-density polyethylene (LDPE) possesses various applications in several industries owing to its durability, low-cost, and many mechano-thermal properties. Unfortunately, LDPE waste creates an environmental threat. The level of biodegradation of black LDPE sheets with fungi isolated from different landfills sites in Sharqiyah Governorate, Egypt, was evaluated. LDPE sheets, the only source of carbon, along with minimal salt medium were incubated on a rotary shaker at 30 °C and 120 rpm for 16 weeks. Aspergillus carbonarius MH 856457.1 and A. fumigatus MF 276893 confirmed to be good candidates for LDPE biodegradation. A mixed culture of two strains showed the excellent weight loss% of sheets as compared to single isolate. Further efforts to improve the degrading capacity through physical and chemical treatments were performed. The biodegradation was significantly stimulated by 39.1% (thermal treatment), 17.76% (HNO3 treatment), and 5.79% (Gamma-irradiation treatment). Laccases and manganese peroxidases activities were assayed. LDPE biodegradation was analyzed by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and gas chromatography–mass spectrometry (GC–MS). FTIR spectra showed the appearance of new functional groups assigned to hydrocarbon biodegradation and confirmed the role of manganese peroxidase in process. The changes in the FTIR spectra of the mixed culture biomass before and after the biodegradation (Δ73 cm−1) and the surface changes in the biodegraded LDPE (as indicated from SEM) confirmed the depolymerization of LDPE. From GC–MS analysis, the plasticizers bis(2-ethylhexyl) phthalate, Diisssctyl phthalate, 1,2-benzenedicarboxylic acid diisooctyl ester, and tributyl acetylcitrate completely biodegraded. Moreover, several antioxidants, antimicrobial, and anticancer compounds, and methyl esters of fatty acids were produced.

Analysis of Lateral Fluid Gradients From DFA Measurements and Simulation of Reservoir Fluid Mixing Processes Over Geologic Time

Downhole fluid analysis (DFA) is one pillar of reservoir fluid geodynamics (RFG). DFA measurements provide both vertical and lateral fluid gradient data. These gradients, especially the asphaltene gradient derived from accurate optical density (OD) measurements, are critical in thermodynamic analysis to assess equilibration level and identify RFG processes. Recently, an RFG study was conducted using DFA and laboratory data from an oil field in the Norwegian North Sea. Fluid OD gradients show equilibrated asphaltenes in most of the reservoir, with a lateral variation of 20%. This indicates connectivity, which is confirmed by three years of production data. Two outliers are off the asphaltene equilibrium curve implying isolated sections, one each on the extreme east and west flank. Their asphaltene fraction varies by a factor of six. Such a difference reveals that different charge fluids entered the reservoir, and the equilibrated asphaltenes are the result of an after-charge mixing process. Meanwhile, different gas-oil contacts (GOCs) exist in the reservoir, indicating a lateral solution-gas gradient. Geochemistry analysis shows the same level of mild biodegradation in all the fluid samples, including those from two isolated sections. This means that biodegraded oil spills into the whole reservoir with little or no in-reservoir biodegradation. Furthermore, lateral asphaltene gradients at different times after charge have been preserved; it was a factor of six in asphaltenes content initially and is now 20% in the present day. This unique data set provides a valuable constraint to simulate reservoir fluid after-charge mixing processes to present day, aiming to investigate the factors impacting the evolution of lateral composition gradients in geologic time in a connected reservoir. Numerical simulations were performed over geologic time in reservoirs filled by oil with a lateral density gradient, which imitates the lateral compositional gradients in the gas-oil ratio (GOR) and asphaltenes measured in the above oil field. Simulations show that this lateral gradient creates lateral differential pressures and causes a countercurrent fluid flow forming a convection cell. In reservoirs with realistic vertical-to-horizontal aspect ratios, such fluid flows are not rapid, and lateral gradients can be partially retained in moderate geologic times. Additionally, diffusion was included in the simulation. The reservoir model was initialized with two GOCs producing subtle lateral GOR and density gradients. The simulated mixing process transports gas from higher GOR regions to lower GOR regions and reduces the GOC difference. However, the flux of solution gas transport is small. Consequently, we conclude that lateral GOR and asphaltene gradients can persist for moderate geologic time, which is consistent with observation from the field.

Recycling Sprout-Growing Mediums in Urban Areas as Compost and New Growing Mediums

Used sprout-growing mediums (SGMs) are nutrient-rich biomass characterised by high lignocellulosic content and low levels of natural biodegradability, producing waste, commonly in urban areas. Accumulation of used SGMs has caused severe environmental pollution in sprout production areas. To reduce waste volume at the source, this study proposed several methods for effectively reusing SGMs in urban areas: producing compost (M1), creating new mediums for growing sprouts (M2), and creating new mediums for growing hydroponic vegetables (M3). First M1, a mixture of used SGM, peanut stalks, urea fertiliser and BIMA microbial product (C: N ratio of 30: 1) was thermophilically composted for 63 d. Then, its chemical and biological properties were analysed. For M2, a mixture of sun-dried used SGM and mung bean sprout husks was crushed and then incubated with the BIMA microbial product for 21 d. For M3, the used SGM was mixed with lime powder and incubated for 7 d before being dried. The products obtained after treating the used SGM demonstrated almost neutral pH reactions (6.37 for M1; 6.31 for M2; 7.52 for M3 - a weakly alkaline reaction). The nutrient content of M1 demonstrated the most organic matter content (OM, 58.44 %), total nitrogen (T-N, 1.77 %), total phosphorus (T-P2O5, 1.62 %), and total potassium (T-K2O, 4.01 %) with a C: N ratio of 15. The M2 medium contained 58.70 % OM, 1.16 % T-N, 0.86 % T-P2O5, and 0.98 % T-K2O, with a C: N ratio of 23. The M3 medium included 72.07 % OM, 0.54 % T-N, 0.55 % T-P2O5, and 0.58 % T-K2O, with a C: N ratio of 63. The heavy metal content (Cu, Zn, Pb, Cd, As) for all products was within the permitted limits. There were no pathogenic microorganisms such as E. coli, Salmonella spp. found in any of the products. Based on the phytotoxicity test, M1 was confirmed to be mature, and M2 could be used to grow sprouts. Lettuce planted in M3 according to the hydroponic method was safe and of good quality. The SGM treatment methods evaluated are accessible and could be applied widely in sprout production locations, especially in urban areas.

Trace gas composition in landfill gas at Danish landfills receiving low-organic waste

In 1997, the landfilling of biodegradable waste was banned in Denmark, and currently Danish landfills receive mostly non-combustible waste with a low-organic content. This study aimed to investigate trace gas composition in landfill gas (LFG) at modern Danish landfills. Landfill gas samples were taken from waste cells containing shredder, mixed and aged waste from four Danish landfills. The highest trace gas concentrations were found in shredder waste cells (average concentration of 103 mg m−3), which were comparable with conventional municipal solid waste landfills receiving organic waste. Aliphatic hydrocarbons and aromatics were dominant in the shredder waste cells, most likely released through direct volatilisation from disposed waste products. Abundant oxygenated compounds were found in the shredder waste cell in one of the landfills, thereby indicating a higher level of organic fraction biodegradation. Benzene, toluene, ethylbenzene and xylenes (BTEXs) were measured in high concentrations in all shredder waste cells, contributing to more than 75% of total aromatics. Considerably lower concentrations of trace gases were measured in the mixed and aged waste cells, which were dominated by hydrogen sulphide and several aliphatic hydrocarbons. A constant concentration ratio was established between aliphatic hydrocarbons together with aromatics and methane in shredder waste cells, which was then used in an LFG generation model to estimate trace gas production. The production rates of BTEXs from two landfills were estimated at 272 and 73 kg yr−1 in 2020, which were not considered to pose a significant risk to the environment or to human health.

Investigation on the biodegradation levels of super heavy oils by parameter-striping method and refined Manco scale: a case study from the Chepaizi Uplift of Junggar Basin

The Carboniferous volcanic reservoir in the Chepaizi Uplift became an exploration hot target in recent years for its substantial amount of oils discovered. However, most of the Carboniferous heavy oils were biodegraded to PM7 or higher with orders of magnitude variation in oil viscosities. Two oil groups (I and II) exactly corresponding to the western and eastern Chepaizi Uplift were distinguished according to their source diagnose. Furthermore, three oil families (II1, II2 and II3), with the biodegradation level of PM7, PM8–8+, PM9+, respectively, were classified based on molecular compositions and parameter-stripping method of strongly bioresistant parameters. Allowing for this extremely high biodegradation case, more biodegradation refractory compound class were added to establish a refined Manco scale to quantitatively evaluate the biodegradation extent. Refined Manco number (RMN2) positively correlated with the oil density, NSO contents, and absolute concentrations of diasteranes and gammacerane, negatively correlated with the absolute concentrations of diahopane, summed tricyclic terpanes and pentacyclic terpanes. This refined scale showed higher resolution than the PM one to differentiate the biodegradation extent of Carboniferous heavy oils from the Chepaizi Uplift, especially those with same PM values but different oil viscosities.

Increasing the biodegradability of epoxy materials by means of vegetable oils and their oxygenated derivatives

Recycling of epoxy resin products is an urgent problem due to the microbiological resistance of such polymers. In this work, we aimed to increase the biodegradability of epoxy materials under the action of soil microorganisms and mycelial fungi. The modification of epoxy materials was carried out using soybean oil, rubber tree oil and their oxygenated derivatives, as well as a mixture of soybean oil and oleic acid. According to the obtained results, the introduction of a material based on unmodified epoxy resin into a soil leads to a 2.2-fold decrease in the respiratory activity of the soil microbiocenosis compared to untreated soil samples. This proves that epoxy-diane resins or hardeners (aminophenol) inhibit soil microbiocenosis. In comparison with the action of unmodified epoxy resins, the epoxy resins treated with vegetable oils and their oxygenated derivatives caused an increase in the respiratory activity of soil microbiocenosis, thus indicating the biodegradability of the materials under study. The decrease in the content of carboxylic acids in the composition of rubber tree oil after its epoxidation, which was confirmed by a decrease in the acid value, led to a slight decrease in the respiratory activity of soil microbiocenosis. For the same reason, the carbonation of vegetable oils had a similar effect. An improved biodegradation profile of epoxy materials following their modification was also confirmed by assessing their fungal resistance in terms of the number of the Tricho-derma fungi. It was concluded that vegetable oils and their oxygenated derivatives increase the biodegradability of epoxy materials. Among all the studied compositions, the epoxy materials modified with rubber tree oil and a mixture of soybean oil and oleic acid demonstrated the highest level of biodegradability.

ИССЛЕДОВАНИЕ ДЕСТРУКТИВНОГО ВОЗДЕЙСТВИЯ ШТАММОВ МИКРОМИЦЕТОВ, ВЫДЕЛЕННЫХ В КЛИМАТИЧЕСКИХ УСЛОВИЯХ РЕСПУБЛИКИ КУБА, НА ПЛЕНОЧНЫЕ ПОЛИМЕРНЫЕ МАТЕРИАЛЫ

A laboratory study for biodegradation of polymer film materials (high-density and low-density polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride) under the action of mircomycete strains isolated under conditions of the island of Cuba was carried out. The maximum growth of micromycetes was observed in case of PVC samples. The minimum level of biodegradation for PVC films revealed at the mould resistance test (28 days) was confirmed by the results of tensile testing.

Overview on Bioconversion of Domestic Wastewater Sewage Sludge into Green Energy: Biogas and Hydrogen

Municipal wastewater treatment plants generate large amounts of sludge after a set of unit processes. The sewage sludge is an important resource for energy production because of its high level of biodegradability. Sewage sludges are generally made of non-toxic and biodegradable organic compounds mixed with a small fraction of non-toxic and toxic inorganic compounds having a very low biodegradability. The large fraction of biodegradable matter constitutes a pool for green/clean energy to be used for industrial and domestic applications. The generated energy can also be used in the wastewater treatment plant. Currently, fossil fuels are leading the energy world, however, they are being depleted and are considered to be among the main causes contributing to climate change and global warming. Domestic sewage sludge can be converted sustainably into bio-hydrogen and bio- methane. This conversion is achievable through anaerobic digestion, combustion, pyrolysis and gasification. With regard to the last three conversion processes, the organic and inorganic toxic compounds are eliminated. Production of biogas from sewage sludge is being undertaken worldwide on small, medium, and large scales. However, hydrogen production from sludge is still developing. There is an existence of substantial knowledge in this field, the production of hydrogen and biogas from sewage sludge is gaining interest. This study analyses various possibilities of sewage sludge conversion into clean energy. The analysis focuses on the technology strengths, weaknesses and gaps to be improved in future studies.

Biodegradation of Phenol by Bacillus simplex: Characterization and Kinetics Study

Phenol is one of the main pollutants that have a serious impact on the environment and can even be very critical to human health. The biodegradation of phenol can be considered an increasingly important pollution control process. In this study, the degradation of phenol by Bacillus simplex was investigated for the first time under different growth conditions. Six different initial concentrations of phenol were used as the primary substrate. Culture conditions had an important effect on these cells' ability to biodegrade phenol. The best growth of this organism and its highest biodegradation level of phenol were noticed at pH 7, temperature 28 °C, and periods of 36 and 96 h, respectively. The GC-MS analysis of the bacterial culture sample revealed that further degradation of the catechol by 1,2-dioxygenase produce a cis, cis-mucconic acid via ortho-pathway and/or by 2,3-dioxygenase into 2-hydroxymucconic semialdehyde via meta-pathway. The highest biodegradation rate was perceived at 700 mg/L initial phenol concentration. Approximately 90% of the phenol (700 mg / L) was removed in less than 96 hours of incubation time. It was found that the Haldane model best fitted the relationship between the specific growth rate and the initial phenol concentration, whereas the phenol biodegradation profiles with time could be adequately described by the modified Gompertz model. The obtained parameters from the Haldane equation are: 1.05 h−1, 9.14 ppm, and 329 ppm for Haldane's maximum specific growth rate, the half-saturation coefficient, and the Haldane’s growth kinetics inhibition coefficient, respectively. The Haldane equation fitted the experimental data by minimizing the sum of squared error (SSR) to 1.36 X 10-3.

Geochemical Characterization of Some Biodegraded Oils from the Niger Delta Basin, Nigeria

This study aimed to examine the compositional changes resulting from biodegradation, fathom the extent of degradation, and provide clues for interpreting the evolution and the overall effects on the quality of the oils. Ten oil samples from onshore-offshore fields were analyzed using gas chromatography (GC) and GC-mass spectrometry (GC-MS) methods. GC results indicate variable loss of low molecular weight (LMW) alkanes, besides the presence of unresolved complex mixture (UCM). Saturated, aromatic, resins, and asphaltenes (SARA) compositions and low saturate/aromatic ratio confirmed evidence of biodegradation. Biodegradation levels of the considered oils range from light to moderate, based on Peters and Moldowan scale. This influenced shifts in the ‘primary compositions’ of oils probably from paraffinic or paraffinic-naphthenic oils to aromatic-naphthenic oils. Total ion chromatograms of well 1 and 2 from Northern depobelt, show presence of LMW alkanes, co-existing side by side with UCM, suggesting multiple charges. However, biomarker fingerprints of the oils lack evidence of in-reservoir mixing of biodegraded and non-biodegraded oils. Nevertheless, the possibility of oil mixing cannot be excluded, because biodegradation is progressive and is ongoing. This study, shows the process has dramatically impacted the fluid properties, commercial worth, and economic producibility of the investigated oil accumulations in the basin.

Bioaccessibility of 14C-phenanthrene from root amended contaminated soil

Plants and their roots, in particular, may be important in stimulating microbial degradation of organic contaminants in soil. It is also known that bioaccessibility is important in controlling the biodegradation of organic contaminants in soil. This study aimed to assess the impact of plant roots on the biodegradation and bioaccessibility of 14C-phenanthrene in soil in the presence of plant root biomass. To do this, changes in the 14C-phenanthrene mineralisable and hydroxypropyl-β-cyclodextrin (HPCD) extractable fractions were evaluated. After 1, 25, 50 and 100 days of PAH-soil contact time, 12/14C-phenanthrene-spiked soil was amended with roots from two grasses and one legume. Mineralisation and HPCD extractability of 14C-phenanthrene were measured after 1, 21 and 42 days PAH-root-soil contact time. Findings revealed that mineralisation of 14C-phenanthrene was enhanced following the amendment with plant root biomass regardless their species or form, especially in the soils that been aged for ≥50 days soil-PAH contact time. Overall, this study showed that greater levels of phenanthrene biodegradation may be achieved by incorporating root biomass into the contaminated soil, particularly where indigenous catabolic activity has developed. The findings reported here contribute to the understanding of how plant root biomass may impact on contaminant bioaccessibility and stimulate the more effective indigenous biodegradation of hydrocarbons in soil.

An application of exploratory factor analysis in the deconvolution of heavy oil biodegradation, charging and mixing history in southeastern Mexico

Forty-seven heavy oil samples of three genetic types and similar maturity levels (early oil window) reflect that oils in the southeastern Mexico Basin have experienced complex oil biodegradation, charging and mixing processes. Strong oil fingerprinting signatures from the non- to slightly biodegraded, later charged oils discourage effective determination of biodegradation levels using the existing biodegradation scales. The later charges are recognized by accumulation of n-alkanes, peak/hump ratios and abundant diamondoids. Bicyclic sesquiterpanes show systematic changes caused by biodegradation, whereas very similar hopane and sterane distribution patterns indicate no obvious microbial alteration of hopanes and steranes. Distributions of 2–5 ring aromatic hydrocarbons display regular trends caused by biodegradation, based on which a biodegradation parameter was derived. It shows a higher resolution than an adapted Manco score (Larter et al., 2012). Biodegradation parameters were also derived based on systematic changes in NSO compound distributions. However, deconvolution of oil biodegradation, charging and mixing history is not achievable from a univariate or bivariate perspective. Hence, a multivariate method, exploratory factor analysis (EFA) was applied, incorporating biodegradation ratios and concentrations of compounds chiefly from the fresh charges. The EFA results categorize the studied oils into three broad biodegradation level ranges along with different amounts of the later fresh charge. Our study highlights that chemometric methods might be used to unravel complex oil biodegradation, charging and mixing history of petroleum systems worldwide.

Application of the Electron Spin Resonance Technique in the Characterization of Brazilian Oils: Correlation with Their Biodegradation Level and Polar Composition

This work combines the outcomes from the electron spin resonance (ESR) analysis of crude oils with the results of their chemical composition from elemental analysis (CHN), gas chromatography with f...

The power of biodegradation and bio-adsorption of bacteria symbiont sponges sea on waste contaminated of polycyclic aromatic hydrocarbons and heavy metals

Sponge is often used as a bio indicator and bio monitoring in determining the level of heavy metal contamination in the sea. The purpose of this research is to analyze the destruction of PAHs and the reduction of heavy metal toxicity. Biodegradation and bio-adsorption occur with a 30-day interaction between bacterial symbiont sponge suspension against modified liquid waste containing a mixture of PAHs (naphthalene) contaminants, heavy metals Cr (VI) and Cd (II). The period of interaction of bacteria with heavy metals for 15 days, bio-adsorption power was determined using AAS, while the interaction with PAHs, the level of biodegradation was measured using GC-MS and Infrared Spectrophotometer. The results achieved bacteria BP and PS, have biodegradation and bio-adsorption activities against extreme waste contaminated with a mixture of naphthalene and heavy metal. The level of biodegradation of BP bacteria to naphthalene is weaker than PS bacteria. The bio-adsorption power of PS bacteria is higher for Cr (VI) and Cd (II) ions. The components of naphthalene in extreme waste inhibit the bio-adsorption performance of BP and PS bacterial, conversely there is an effect of inhibition of bacterial activity on the biodegradation process of naphthalene by the presence of heavy metals.

Classical Biomarker and Quantitative Extended Diamondoid Analysis Fingerprints for Crude Oils from Deepwater Developments in Block 17, Lower Congo Basin, Angola.

The organic geochemistry of six oil samples from the offshore Block 17 (Lower Congo Basin, northwestern Angola) was studied by a combination of classical biomarker and extended diamondoid analyses to elucidate source rock facies, the extent of biodegradation, and thermal maturity. Based on molecular data, oils are interpreted as depicting a mixture of two pulses of hydrocarbon generation probably from the Bucomazi and Malembo formations. Geochemical results also gave evidence of mixing of a lacustrine siliciclastic-sourced oil charge and a second more terrestrially derived oil type in the samples analyzed. A single genetic oil family was identified through hierarchical cluster analysis; however, two groups of oils were identified on the basis of their biodegradation levels using the Peters/Moldowan scale. Lower and upper Malembo oils have a slight depletion and a notable absence of n-alkanes, suggesting PM levels of 1 and 2, respectively. Most molecular maturity parameters of the oil samples suggest a maturity level equivalent to the onset of the peak of the oil generative window.

Biomarker assessment of oil biodegradation, water washing, and source rock characteristics of oil seeps from the Foothill Zone along the Tigris River, Northern Iraq

Oil seep samples from the Foothill Zone of northern Iraq were geochemically characterized to determine the level of biodegradation and water washing of the seeps and to determine the depositional environment (including sedimentary facies, oxicity, and organic matter type) of correlative source rocks. Eight samples from three seeps sites (Hammam Al-Alil, Qaiyarah, and Fat'ha) were investigated. Detailed saturated and aromatic biomarkers were analyzed using GC-FID and GC-MS, in addition to measurement of carbon isotopes and the sulphur content. Qaiyarah samples range from non-biodegraded to moderately biodegraded; whereas Hammam Al-Alil and Fat'ha samples are moderately biodegraded. The Hammam Al-Alil and Fat'ha samples are also affected by water washing. Biomarker, carbon isotope, and sulphur data suggest that these oil seeps contain oil expelled during the early oil window from carbonate source rocks of Jurassic age. Correlative source rocks were deposited in an anoxic marine environment. The most likely source rock candidates include the Sargelu, Naoklekan, and Chia Gara formations.