Variation in Petroleum Hydrocarbon Chain Lengths with Depth at a Former Crude Oil and Natural Gas ProductionFacility

An investigation was performed at a former crude oil and natural gas production facility to evaluate whether releases from the product flowlines, gathering lines or water injection lines had impacted soil beneath the site. Thirty-six trenches were initially excavated and sampled beneath the former piping runs to a maximum depth of 6?m. After the trenching investigation, nine soil boreholes were advanced and sampled to a depth of approximately 18?m to further delineate the lateral and vertical extent of impacted soil. Soil samples collected from the trenches and boreholes were analyzed for total petroleum hydrocarbons (TPH) in accordance with ASTM Method 2887. The results of the investigation indicated that TPH impacted soil was present within several areas of the 40-ha site. The petroleum hydrocarbons generally had chain lengths ranging from C₆ to C₃₅, characteristic of light crude oil. The impacted soil also contained condensate, the volatile portion of crude oil. Condensate consists of short-chain hydrocarbons (C₁ to C₁₂) and is characterized by low levels of aromatic volatile organic compounds (VOCs). The condensate typically was more prevalent at depths below 4.5?m than the less volatile, longer chain length hydrocarbons. Statistical analysis of TPH data collected during subsequent excavation activities showed that the mean percentage of condensate was significantly greater at depths below 4.5?m than in shallower samples. In contrast, the mean percentage of TPH compounds in the diesel range (C₁₄ to C₂₃) was significantly greater in samples collected at depths above 4.5?m. The difference in the mean percentage of heavier hydrocarbons (C₂₄ to C₄₄+) with depth was not statistically significant.     

Biotransformation and Dissolution of Petroleum Hydrocarbons in Natural Flowing Seawater at Low Temperature

The objective of this study was to establish methods for controlled studies of hydrocarbon depletion from thin oil films in cold natural seawater, and to determine biotransformation in relation to other essential depletion processes. Mineral oil was immobilized on the surface of hydrophobic Fluortex fabrics and used for studies of microbial biodegradation in an experimental seawater flow-through system at low temperatures (5.9-7.4 degrees C) during a test period of 42 days. The seawater was collected from a depth of 90 m, and microbial characterization by epifluorescence microscopy, fluorescence in situ hybridization, and most-probable number analysis showed relatively larger fractions of archaea and oil-degrading microbes than in the corresponding surface water. Chemical analysis of hydrocarbons attached to the fabrics during the test period showed that n-alkanes (C10-C36) were decreased by 98% after 21 days, while naphthalenes were depleted by 99-100% during the same period. At the end of the period 4-5 ring polyaromatic hydrocarbon (PAH) compounds were removed by 82% from the fabrics. Analysis of the recalcitrant pentacyclic triterpane C30 17alpha(H),21beta(H)-hopane showed that the oil remained adsorbed to the fabrics during the test period. Comparison of depletion analysis with calculation of hydrocarbon dissolution in a flow-through system indicated that naphthalenes and smaller PAH compounds (alkylated 2-ring and 3-ring compounds) were removed from the fabrics by dissolution. The data further implied that depletion of n-alkanes and 4-5 ring PAH hydrocarbons were the result of biotransformation processes. PCR amplification of bacterial 16S rRNA genes from microbes adhering on the immobilized oil surfaces showed the dominance of a few bands when analysed in denaturing gradient gel electrophoresis (DGGE). Sequence analysis of DGGE bands revealed phylogenetic affiliation to the alpha- and gamma-subdivisions of proteobacteria and to the Chloroflexus-Flavobacterium-Bacteroides group.     

Stimulation of hybrid poplar growth in petroleum-contaminated soils through oxygen addition and soil nutrient amendments

Hybrid poplar trees (Populus deltoides x nigra DN34) were grown in a green-house using hydrocarbon-contaminated soil from a phytoremediation demonstration site in Health, Ohio. Two independent experiments investigated the effect of nutrient addition on poplar growth and the importance of oxygen addition to root development and plant growth. Biomass measurements, poplar height, and leaf color were used as indicators of plant health in the selection of a 10/5/5 NPK fertilizer applied at 1121 kg/ha (112 kg-N, 24.4 kg-P, 46.5 kg-K per ha) to enhance hybrid poplar growth at the Health site. Five passive methods of oxygen delivery were examined, including aeration tubes, gravel addition, and an Oxygen Release Compound (ORC). When ORC was placed in coffee filters above hydrocarbon-contaminated soil, a statistically significant increase of 145% was observed in poplar biomass growth, relative to unamended controls. The ORC in filters also stimulated significant increases in root density. A 15.2-cm interval of soil directly below ORC addition exhibited an increase from 2.6 +/- 1.0 mg/cm3 to 4.8 +/- 1.0 mg/cm3, showing stimulation of root growth in hydrocarbon-stained soil. The positive response of hybrid poplars to oxygen amendments suggests that overcoming oxygen limitation to plants should be considered in phytoremediation projects when soil contamination exerts a high biochemical oxygen demand, such as in former refinery sites.     

Transport model parameter sensitivity for soil cleanup level determinations using sesoil and at123d in the context of the california leaking underground fuel tank field manual

The California Leaking Underground Fuel Tank Field Manual (LUFT Manual; WRCB, 1989) is used by the regulatory community, consultants, and industry in California to determine acceptable cleanup concentration goals for the remediation of hydrocarbon‐affected soils. The LUFT methodology is a semiquanitative approach that uses rating tables that consider the effects of local precipitation and the depth to ground water from the deepest affected soils, as well as anthropogenic and geologic factors. The latter factors are evaluated subjectively, with only the effects of local precipitation and depth to ground water accounted for quantitatively. To assess the effects of these variables on the hydrocarbon concentrations that could be left in soil while protecting ground water quality, the state of California performed modeling using SESOIL and AT123D. The results from a small number of simulations covering a very narrow range of input parameter values were then extrapolated to form the LUFT Manual rating tables, which cover ranges in precipitation and depth to ground water of 0 to 40 in. per year and 5 to 150 ft, respectively. Although the use of these tables generally results in conservative cleanup level determinations, the extrapolation method used and the lack of consideration for extremely sensitive input parameters (other than precipitation and depth to ground water) in the development of the tables calls into question their validity. A sensitivity analysis on the model input parameters is presented that highlights several critical input parameters that greatly affect cleanup concentration determinations. The sensitivity analysis shows that certain parameters that were fixed at conservative levels for the development of the LUFT Manual rating tables (e.g., biodegradation rate and soil organic carbon content) are more sensitive than precipitation and the depth to ground water. In many cases, site‐specific analysis will thus yield higher soil cleanup concentrations that are still protective of water quality. In addition, in some instances the cleanup concentrations in the LUFT Manual tables are not protective of water quality. To provide a firm basis for soil cleanup‐level determinations, site‐specific analysis is recommended whenever significant quantities of soil may require remediation. This will provide more cost‐effective remediation and greater assurance of water quality protection.     

An Improved CARV Process for Bioethanol Production from a Mixture of Sugar Beet Mash and Potato Mash

A mixed mash of sugar beet roots and potato tubers with a sugar concentration of 23.7% w/v was used as a feedstock for bioethanol production. Enzymatic digestion successfully reduced the viscosity of the mixture, enabling subsequent heat pretreatment for liquefaction/sterilization. An energy-consuming thick juice preparation from sugar beet for concentration and sterilization was omitted in this new process.     

High titer ethanol production from simultaneous enzymatic saccharification and fermentation of aspen at high solids: a comparison between SPORL and dilute acid pretreatments

Native aspen (Populus tremuloides) was pretreated using sulfuric acid and sodium bisulfite (SPORL) and dilute sulfuric acid alone (DA). Simultaneous enzymatic saccharification and fermentation (SSF) was conducted at 18% solids using commercial enzymes with cellulase loadings ranging from 6 to 15 FPU/g glucan and Saccharomyces cerevisiae Y5. Compared with DA pretreatment, the SPORL pretreatment reduced the energy required for wood chip size-reduction, and reduced mixing energy of the resultant substrate for solid liquefaction. Approximately 60% more ethanol was produced from the solid SPORL substrate (211 L/ton wood at 59 g/L with SSF efficiency of 76%) than from the solid DA substrate (133 L/ton wood at 35 g/L with SSF efficiency 47%) at a cellulase loading of 10 FPU/g glucan after 120 h. When the cellulase loading was increased to 15 FPU/g glucan on the DA substrate, the ethanol yield still remained lower than the SPORL substrate at 10 FPU/g glucan.     

Design and synthesis of new antitumor agents with the 1,7-epoxycyclononane framework. Study of their anticancer action mechanism by a model compound

This article describes the design, synthesis and biological evaluation of a new family of antitumor agents having the 1,7-epoxycyclononane framework. We have developed a versatile synthetic methodology that allows the preparation of a chemical library with structural diversity and in good yield. The synthetic methodology has been scaled up to the multigram level and can be developed in an enantioselective fashion. The study in vitro of a model compound, in front of the cancer cell lines HL-60 and MCF-7, showed a growth inhibitory effect better than that of cisplatin. The observation of cancer cells by fluorescence microscopy showed the presence of apoptotic bodies and a degradation of microtubules. The study of cell cycle and mechanism of death of cancer cells by flow cytometry indicates that the cell cycle arrested at the G₀/G₁ phase and that the cells died by apoptosis preferably over necrosis. A high percentage of apoptotic cells at the subG₀/G₁ level was observed. This indicates that our model compound does not behave as an antimitotic agent like nocodazole, used as a reference, which arrests the cell cycle at G₂/M phase. The interaction of anticancer agents with DNA molecules was evaluated by atomic force microscopy, circular dichroism and electrophoresis on agarose gel. The results indicate that the model compound has not DNA as a target molecule. The in silico study of the model compound showed a potential good oral bioavailability.