Total organic carbon content, methane isotopic composition and hydrocarbon characteristics of ODP Leg 180 sites

The organic geochemistry of Sites 1108 and 1109 of the Woodlark Basin, offshore Papua New Guinea, was studied to determine whether thermally mature hydrocarbons were present in the penetrated section and, if present, whether they are genetically related to the penetrated "coaly" interval. Both the organic carbon and pyrolysis data indicate that there is no significant hydrocarbon source-rock potential at Site 1108. The hydrocarbons encountered during drilling appear to be indigenous and not migrated products or contaminants. In contrast, the coaly interval at Site 1109 contains zones with significant hydrocarbon-generation potential. Several independent lines of evidence indicate that the coaly sequence encountered at Site 1109 is thermally immature. The Site 1108 methane stable-carbon isotope composition does not display a clear trend with depth as would be expected if it was solely reflecting a maturation profile. The measured isotopic composition of methane has most probably been altered by fractionation during sample handling and storage. This fractionation would result in isotopically heavier values than would be obtained on free gas. The organic geochemical data gathered indicate that Site 1108 can be safely revisited and that the organic-rich sediments encountered at Site 1109 were not the source of the gas encountered at Site 1108.

Alkane and hydrocarbon concentrations of ODP Leg 104 sites

Sedimentary extractable organic matter was analyzed at three ODP Leg 104 sites in the Norwegian Sea. Organic carbon content ranged from less than 0.1% to a maximum of 1.8%. Extractable organic matter content and unresolved complex mixture concentrations were low and randomly distributed. Low levels of aliphatic (branched and normal) and aromatic hydrocarbons were detected in all of the sediments analyzed. Total aliphatic and aromatic hydrocarbon concentrations ranged from 176 to 3,214 and 6 to 820 ppb, respectively. The concentrations of individual aliphatic (n-C15 to n-C32) and aromatic (two- to five-ring) hydrocarbons were generally less than 50 ppb and less than 10 ppb, respectively. No significant trend with sub-bottom depth was observed in either bulk organic matter or individual hydrocarbon concentrations. The predominant source of Cenozoic sedimentary hydrocarbons is concluded to be ice-rafted debris from the adjacent continent. All sites contain a mixture of recycled, mature petroleum-related and terrestrially derived hydrocarbons.

Heat shock protein hsp90 regulates dioxin receptor function in vivo.

The dioxin (aryl hydrocarbon) receptor is a ligand-dependent basic helix-loop-helix (bHLH) factor that binds to xenobiotic response elements of target promoters upon heterodimerization with the bHLH partner factor Arnt. Here we have replaced the bHLH motif of the dioxin receptor with a heterologous DNA-binding domain to create fusion proteins that mediate ligand-dependent transcriptional enhancement in yeast (Saccharomyces cerevisiae). Previously, our experiments indicated that the ligand-free dioxin receptor is stably associated with the 90-kDa heat shock protein, hsp90. To investigate the role of hsp90 in dioxin signaling we have studied receptor function in a yeast strain where hsp90 expression can be down-regulated to about 5% relative to wild-type levels. At low levels of hsp90, ligand-dependent activation of the chimeric dioxin receptor construct was almost completely inhibited, whereas the activity of a similar chimeric construct containing the structurally related Arnt factor was not affected. Moreover, a chimeric dioxin receptor construct lacking the central ligand- and hsp90-binding region of the receptor showed constitutive transcriptional activity in yeast that was not impaired upon down-regulation of hsp90 expression levels. Thus, these data suggest that hsp90 is a critical determinant of conditional regulation of dioxin receptor function in vivo via the ligand-binding domain.

Phase and partitioning behavior of phenols and polycyclic aromatic hydrocarbons in offshore oil and gas produced water

Produced water constitutes the largest volume of waste from offshore oil and gas operations and is composed of a wide range of organic and inorganic compounds. Although treatment processes have to meet strict oil in water regulations, the definition of “oil” is a function of the analysis process and may include aliphatic hydrocarbons which have limited environmental impact due to degradability whilst ignoring problematic dissolved petroleum species. This thesis presents the partitioning behavior of oil in produced water as a function of temperature and salinity to identify compounds of environmental concern. Phenol, p-cresol, and 4-tert-butylphenol were studied because of their xenoestrogenic power; other compounds studied are polycyclic aromatic hydrocarbon PAHs which include naphthalene, fluorene, phenanthrene, and pyrene. Partitioning experiments were carried out in an Innova incubator for 48 hours, temperature was varied from 4ﾟC to 70ﾟC, and two salinity levels of 46.8‰ and 66.8‰ were studied. Results obtained showed that the dispersed oil concentration in the water reduces with settling time and equilibrium was attained at 48 h settling time. Polycyclic aromatic hydrocarbons (PAHs) partitions based on dispersed oil concentration whereas phenols are not significantly affected by dispersed oil concentration. Higher temperature favors partitioning of PAHs into the water phase. Salinity has negligible effect on partitioning pattern of phenols and PAHs studied. Simulation results obtained from the Aspen HYSYS model shows that temperature and oil droplet distribution greatly influences the efficiency of produced water treatment system.

Modulation of CYP1A1 by PKC Inhibitors and TPA Pre-Treatments in MH1C1 Rat Hepatoma Cells Exposed to 3 -Methylcholanthrene

Cytochrome P4501A1 (CYP1A1), an enzyme known to metabolize polycyclic aromatic hydrocarbons, is regulated by the aryl hydrocarbon receptor (AhR). The involvement of protein kinase C (PKC) in the regulation of AhR signal transduction pathway, has been widely studied but the role of specific PKC isoform(s) involved in this process it is not well clarified. To study which PKC isoform(s) is implicated in the regulation of CYP1A1, in the poorly tumorigenic MH1C1 rat hepatoma cells, we examined the effects of some PKC pharmacological inhibitors, Calphostin C (CAL), Staurosporine (STA) and H7, and of 12-0-tetradecanoyl phorbol 13-acetate (TPA), a PKC activator, on basal and 3- methylcholanthrene (MC)-induced CYP1A1 protein expression and mediated ethoxyresorufin O-deethylation (EROD) activity. In parallel, the activities of PKC-α, -βI, -δ and -ε isoforms, the most expressed in MH1C1 cells, were monitored. After pre-treatment with CAL, STA and H7, the MC-induced CYP1A1 protein and EROD activity were rapidly reduced with temporal profile similar to the profile of the activity of α and β1 PKC isoforms. Moreover, TPA pre-treatment induced a biphasic effect on EROD activity, and a decline of PKC -βI and -α, in first instance, and -δ and -ε activities later on. These findings clearly show that, in MH1C1 cells, PKC is involved in CYP1A1 regulation and that α and βI classic PKC isoforms play an active role in modulating this process.

Hidrocarbonetos aromáticos policíclicos em margarina, creme vegetal e maionese

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that have been the subject of much concern due to their toxic potential. In this study, margarine?s, vegetable cream and mayonnaise available on the Brazilian market were analyzed for pyrene, chrysene, benzo(a)pyrene, benzo(b)fluoranthene and dibenzo(a,h)anthracene. The analytical methodology involved liquid-liquid extraction, clean-up on silica gel column and determination by high performance liquid chromatography using fluorescence detector. Variable levels of contamination were found within differents brands of the same product and within differents batches of the same brand. The total PAH content was in the range of 4.1 to 7.1mug/kg in vegetable cream, 1.7 to 3.9mug/kg in margarine and 1.0 to 21.7mug/kg in mayonnaise. In general the products which according to the label contain corn oil showed the highest levels of contamination. Based on these results and on the importance of fat, oils and derived products for the intake of PAHs, it is recommended that producers of margarine, vegetable creams and mayonnaise start to control the contamination of the vegetable oils used in the elaboration of these products, in order to reduce the exposure of consumers to excessive amounts of potentially carcinogenic compounds.

Técnicas de extrações e procedimentos de clean-up para a determinação de hidrocarbonetos policílicos aromáticos (HPA) em sedimentos da costa do Ceará

Extraction and clean-up are essential points in polycyclic aromatic hydrocarbon (PAHs) analysis in a solid matrix. This work compares extraction techniques and clean-up procedures for PAH analysis. PAH levels, their toxicological significance and source were also evaluated in the waters of the Cocó and Ceará rivers. The efficiency of PAH recovery was higher for the soxhlet and ultrasonic techniques. PAH recovery varied from 69.3 to 99.3%. Total PAH concentration (ΣHPA) varied from 720.73 to 2234.76 µg kg-1 (Cocó river) and 96.4 to 1859.21 µg kg-1 (Ceará river). The main PAH sources are pyrolytic processes and the levels were classified as medium so that adverse effects are possible.

Emissions from the premixed combustion of gasified polyethylene

An investigation was conducted on pollutants emitted from steady-state, steady-flow gasification and combustion of polyethylene (PE) in a two-stage furnace. The polymer, in pulverized form, was first pyrolyzed at 1000 degrees C, and subsequently, its gaseous pyrolyzates were burned, upon mixing with air at high temperatures (900-1100 degrees C). The motivation for this indirect type of burning PE was to attain nominally premixed combustion of the pyrolyzate gases with air, thereby achieving lower pollutant emissions than those emanating from the direct burning of the solid PE polymer. This work assessed the effluents of the two-stage furnace and examined the effects of the combustion temperature, as well as the polymer feed rate and the associated fuel/air equivalence ratio (0.3 < phi < 1.4). It was found that, whereas the yield of pyrolysis gas decreased with an increasing polymer feed rate, its composition was nearly independent of the feed rate. CO2 emissions peaked at an equivalence ratio near unity, while the CO emissions increased with an increasing equivalence ratio. The total light volatile hydrocarbon and semivolatile polycyclic aromatic hydrocarbon (PAH) emissions of combustion increased with an increasing equivalence ratio. The generated particulates were mostly submicrometer in size. Overall, PAH and soot emissions from this indirect burning of PE were an order of magnitude lower than corresponding emissions from the direct burning of the solid polymer, obtained previously in this laboratory using identical sampling and analytical techniques. Because pyrolysis of this polymer requires a nominal heat input that amounts to only a diminutive fraction of the heat released during its combustion, implementation of this technique is deemed advantageous.

Application of Fluorescence to the Study of Crude Petroleum

Crude petroleum oils are complex mixtures of different compounds (mainly organic), which are obtained from an extensive range of different geological sources. The fluorescence of crude petroleum oils derives largely from the aromatic hydrocarbon fraction, and this fluorescence emission is strongly influenced by the chemical composition (e.g., fluorophore and quencher concentrations) and physical characteristics (e.g., viscosity and optical density) of the oil. The fluorescence spectroscopy (FS) is increasingly used in petroleum technology due the availability of better optical detection techniques, because FS offers high sensitivity, good diagnostic potential, and relatively simple instrumentation. In this work we analyzed crude petroleum at different dilution in Nujol, a transparent mineral oil. The main objective of this work was to verify the possibility to measure crude oil emission spectroscopic without use of volatile solvents. The mixtures of nujol with different -crude oil concentrations were measured with a 10 mm optical path cuvette thus simplifying the fluorescence spectroscopy signal detection. The emission spectra were obtained by exciting the samples with a 400 W Xenon lamp at 350 nm, 450 nm and 532 nm. The emissions of the samples were collected perpendicularly with the excitation axis.

Low dose of fine particulate matter (PM2.5) can induce acute oxidative stress, inflammation and pulmonary impairment in healthy mice

Air pollution is associated with morbidity and mortality induced by respiratory diseases. However, the mechanisms therein involved are not yet fully clarified. Thus, we tested the hypothesis that a single acute exposure to low doses of fine particulate matter (PM2.5) may induce functional and histological lung changes and unchain inflammatory and oxidative stress processes. PM2.5 was collected from the urban area of Sao Paulo city during 24 h and underwent analysis for elements and polycyclic aromatic hydrocarbon contents. Forty-six male BALB/c mice received intranasal instillation of 30 mu L of saline (CTRL) or PM2.5 at 5 or 15 mu g in 30 mu L of saline (P5 and P15, respectively). Twenty-four hours later, lung mechanics were determined. Lungs were then prepared for histological and biochemical analysis. P15 group showed significantly increased lung impedance and alveolar collapse, as well as lung tissue inflammation, oxidative stress and damage. P5 presented values between CTRL and P15: higher mechanical impedance and inflammation than CTRL, but lower inflammation and oxidative stress than P15. In conclusion, acute exposure to low doses of fine PM induced lung inflammation, oxidative stress and worsened lung impedance and histology in a dose-dependent pattern in mice.

Regulation of type 17 helper T-cell function by nitric oxide during inflammation

Type 17 helper T (Th17) cells are implicated in the pathogenesis many of human autoimmune diseases. Development of Th17 can be enhanced by the activation of aryl hydrocarbon receptor (AHR) whose ligands include the environmental pollutant dioxin, potentially linking environmental factors to the increased prevalence of autoimmune disease. We report here that nitric oxide (NO) can suppress the proliferation and function of polarized murine and human Th17 cells. NO also inhibits AHR expression in Th17 cells and the downstream events of AHR activation, including IL-22, IL-23 receptor, and Cyp1a1. Conversely, NO did not affect the polarization of Th17 cells from mice deficient in AHR. Furthermore, mice lacking inducible nitric oxide synthase (Nos2(-/-)) developed more severe experimental autoimmune encephalomyelitis than WT mice, with elevated AHR expression, increased IL-17A, and IL-22 synthesis. NO may therefore represent an important endogenous regulator to prevent overexpansion of Th17 cells and control of autoimmune diseases caused by environmental pollutants.

Implementação, validação e análise técnico-económico de alguns parâmetros analíticos no controlo de águas

Mestrado em Engenharia Química

PAH air pollution at a Portuguese urban area: carcinogenic risks and sources identification

This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM10 and PM2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO2, PM10, NO2, CO, and O3; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ngm−3, surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10−6) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98×10−7 in PM10 and 1.06×10−6 in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at the respective area. Additionally, principal component regression indicated that SO2, NO2, PM10, CO, and solar radiation had positive correlation with PAHs concentrations, while O3, temperature, relative humidity, and wind speed were negatively correlated.

Development of an integrative approach for the characterization of ecological risk on marine transition ecosystems: the Sado Estuary as a case study

Estuaries and other transitional waters are complex ecosystems critically important as nursery and shelter areas for organisms. Also, humans depend on estuaries for multiple socio-economical activities such as urbanism, tourism, heavy industry, (taking advantage of shipping), fisheries and aquaculture, the development of which led to strong historical pressures, with emphasis on pollution. The degradation of estuarine environmental quality implies ecologic, economic and social prejudice, hence the importance of evaluating environmental quality through the identification of stressors and impacts. The Sado Estuary (SW Portugal) holds the characteristics of industrialized estuaries, which results in multiple adverse impacts. Still, it has recently been considered moderately contaminated. In fact, many studies were conducted in the past few years, albeit scattered due to the absence of true biomonitoring programmes. As such, there is a need to integrate the information, in order to obtain a holistic perspective of the area able to assist management and decision-making. As such, a geographical information system (GIS) was created based on sediment contamination and biomarker data collected from a decade-long time-series of publications. Four impacted and a reference areas were identified, characterized by distinct sediment contamination patterns related to different hot spots and diffuse sources of toxicants. The potential risk of sediment-bound toxicants was determined by contrasting the levels of pollutants with available sediment quality guidelines, followed by their integration through the Sediment Quality guideline Quotient (SQG-Q). The SQG-Q estimates per toxicant or class was then subjected to georreferencing and statistical analyses between the five distinct areas and seasons. Biomarker responses were integrated through the Biomarkers Consistency Indice and georreferenced as well through GIS. Overall, in spite of the multiple biological traits surveyed, the biomarker data (from several organisms) are accordant with sediment contamination. The most impacted areas were the shipyard area and adjacent industrial belt, followed by urban and agricultural grounds. It is evident that the estuary, although globally moderately impacted, is very heterogeneous and affected by a cocktail of contaminants, especially metals and polycyclic aromatic hydrocarbon. Although elements (like copper, zinc and even arsenic) may originate from the geology of the hydrographic basin of the Sado River, the majority of the remaining contaminants results from human activities. The present work revealed that the estuary should be divided into distinct biogeographic units, in order to implement effective measures to safeguard environmental quality.