Carcinogenic Polynuclear Aromatic Hydrocarbons Research Articles

DISTRIBUTION OF POLYNUCLEAR AROMATIC AND TOTAL ALIPHATIC HYDROCARBON CONTENTS IN SURFACE WATER AND SEDIMENTS OF SOMBRIERO RIVER IN RIVERS STATE, NIGERIA

Variations in Polynuclear Aromatic Hydrocarbons (PAH) and Total Aliphatic Hydrocarbon (TAH) concentrations in surface water and sediments of Sombriero River during wet and dry climatic conditions and their implications to human health and the environment were investigated. The sediments and water samples were collected from seven selected stations at Sombriero river banks and within Sombriero River. The dry season sampling was carried out in December, 2020 while the wet season sampling took place in May, 2021. The samples were analyzed in the laboratory for Polynuclear Aromatic Hydrocarbons (PAH’s), and Total aliphatic Hydrocarbons (TAHs) following the standard operational procedures. The results indicated that the summation of the Polynuclear Aromatic Hydrocarbon (\(\Sigma\)PAH’s) exceeded 0 – 50ng/l background value signifying contamination by polynuclear aromatic hydrocarbon with congeners such as benzo(a) pyrene; benzoflouranthenes; benzo(a) anthracene; indeno(1,2,3-cd) pyrene and dibenzo(a,h) anthracene which are carcinogenic. The aliphatic fraction of the total petroleum hydrocarbons (TPH) results indicated ranges within DPR target and intervention limits, but the aromatic fraction indicated presence of chemical compounds that are carcinogenic to human health and at concentrations that exceeded their tolerable limits. The potential health effect of concentrations of total petroleum hydrocarbons to human exposure in the study area lies on the carcinogenic Polynuclear Aromatic Hydrocarbons (PAHs) fractions constituent chemical compounds such as Benz[a]anthracene, Benzo[b]fluoranthene, Benzo[k]fluoranthene, Benzo[a]pyrene, Dibenz [a,h] anthracene, Indeno[1,2,3-cd]pyrene, whose concentrations portends human health hazard.

Extractive Dearomatization of Naphthalane Oil Fraction with Ionic Liquid and -N-Methyl-2-Pyrrolidone

In the article are given an analysis of the results of researches carried out for the purpose of selective treatment of the Naphthalane oil fraction boiling at 260-3400C with ionic liquid (IL) -morfolinphormiate synthesized on the basis formic acid + morpholine and - N-methyl-2-pyrrolidon (N-MP) and as an extractant. The aim is to remove poisonous components - sulfur compounds and toxic carcinogenic polynuclear aromatic hydrocarbons in order to improve therapeutic properties of Naphthalane oil cut. For this purpose we have used extraction method. On the basis of the conducted researches the role of -N-methyl-2-pyrrolidone and IL-morpholinephormiatee in extraction conditions have been determined in selective treatment of Nafthalan oil, according to the results of spectral analysis residual amount of aromatic hydrocarbons decreased from 18.5% wt accordance to 2%, 1.5%. As well as the amount of sulphur decreased from 0.0354% to 0.010%, 0.011% and 0.019%.In the next stage the treated raffinates with N-methyl-2-pyrrolidone has been purified on silica. In a result amount of aromatic hydrocarbons drastically decrease to be 0.07% and 0.02%. As a result we aquire transparency and at the same time the percentage amount of aromatic hydrocarbons drastically decreased from 2% to 0,07%, 1.5%, to 0.02%. Raffinates obtained in a 2-4 stage dearomatization with N-MP and IL. Raffinate are measured on NMR, UV and IR spectral analysis.

Photoreactors for Solving Problems of Environmental Pollution

Involvement of a huge amount of natural resources in the production sphere, synthesis of new materials and substances, and uncontrollable increase in the amount and volume of manufactured products engender a global problem of recycling and utilization of production and consumption wastes. The Earth atmosphere, hydrosphere and lithosphere are polluted. The atmosphere is a giant open reactor without walls in which hundreds of photochemical, dark, gas phase, liquid phase, homogeneous, and heterogeneous reactions take place with participation of all types of particles at various local temperatures and global pressure for different concentrations of substances and radiation intensities at different wavelengths. Hydroxyl radicals dominate in tropospheric chemistry as well as oxygen atoms and ozone dominate in stratospheric chemistry. Moreover, the photochemical processes proceed not only in surface waters, but also in the lithosphere in the upper soil layers [1, 2]. Anthropogenic effect on nature has already caused irreversible consequences. As a result of human activity, pollutants of many types are present in the environment. Chemistry of polluted urban atmospheres obligatory includes the photochemical processes. The typical pollutants presented in the photochemical (or Los Angeles) smog are ozone and nitrogen dioxide in combination with various organic compounds. The O3 and NO2 concentrations can be so high that ozone even smells, and large concentrations of aerosol particles cause the formation of grayish-brown haze in air. The pollution causes such consequences as destruction of materials, for example rubber, suppression of vegetation growth, reduction of the visibility range, and increase in the number of respiratory diseases. The most obvious consequence of the photochemical smog that manifests immediately is eye irritation caused by such compounds as formaldehyde, acrolein, and peroxyacetyl nitrate. The surface of solid aerosols and the inner volume of liquid-drop aerosols can also be the arena of various dark and photostimulated chemical reactions whose rates are largely determined by the catalytic properties of the surface and components forming particles. Many toxic impurities are detected in the aerosol composition, including compounds of heavy metals, carcinogenic polynuclear aromatic hydrocarbons, and polychlorinated compounds of different classes (pesticides, biphenyls, dibenzo-p-dioxins, and dibenzofurans). The largest amounts of these toxicants are contained in the smallest aerosol fractions capable of penetrating deep into the human respiratory tract and then into the blood system. Wide use of pesticides and herbicides in agriculture for the past few decades has significantly increased the number of persistent organic compounds in natural waters and soils [3–5]. For these reasons, the necessity arose to revise old technologies and to develop new ones aimed at resource saving and environmental protection. Experimental

Abstract 5551: Potentiation of PAH-induced cell transformation by phenolic fraction of tobacco smoke: A mechanistic insight

Abstract It is reported that the known content of carcinogenic polynuclear aromatic hydrocarbons (PAHs) in the tobacco smoke condensate (TSC) alone cannot account for the observed carcinogenicity of the TSC tested on mouse skin (Orris, L. et.al., 1958. J. Natl. Cancer Inst., 21: 557-561). The phenolic fraction of TSC (TSCPhFr) which is devoid of PAHs exhibits strong tumor-promoting activity in mouse skin initiated with PAHs (Roe et. al., 1959. Brit. J. Cancer., 13: 623-633). The mechanism(s) underlying the tumor promoting effect of TSCPhFr is not known. In the present communication we report that (±)-anti-BP-7,8-diol-9,10-epoxide (BPDE), an ultimate carcinogenic metabolite of tobacco smoke carcinogen benzo[a]pyrene, elicits both apoptosis induction and cell transformation in promotion sensitive mouse epidermal JB6 cell which has been extensively used for tumor promotion studies. We observed that TSCPhFr significantly potentiates BPDE-induced cell transformation associated with decreased apoptosis response indicating its tumor promoting potential. Increased cell transformation and decreased apoptosis by TSCPhFr was associated with attenuation of BPDE-induced p53 accumulation and NF-κB activation. We examined whether attenuation of p53 and NF-κB responses by TSCPhFr has any role in this regard. Chemical inhibition of p53 in JB6 cells using known p53 inhibitor pifithrin alpha showed potentiation of BPDE-induced p53 accumulation instead of down-regulation as expected. Since pifithrin alpha's role in p53 inhibition is controversial as reported in many studies, we used genomic inhibitor (p53 siRNA) to down-regulate p53 response. We observed that either JB6 cells transfected with p53 siRNA or p53 deficient HCT116 cells (HCT116p53-/−) shows significantly less apoptosis induction and more colony formation on soft agar by BPDE compared to control cells. In p53 impaired both cell lines (which are observed to have faster growth rate compared to normal cells) TSCPhFr has practically negligible effect on apoptosis induction and soft agar colony formation in response to BPDE. Interestingly treatment of cells with IKK-NBD peptide NF-κB-specific inhibitor) has variable effects on BPDE-induced apoptosis induction and cell transformation. Our observations indicate that attenuation of BPDE-induced p53 response by TSCPhFr has a role in apoptosis inhibition and increased cell transformation. These findings have implication with regard to the underlying mechanism of tumor promoting activity of TSCPhFr in PAH-induced carcinogenesis. Although p53 mediated NF-κB activation is involved in DNA damage-induced apoptosis induction as reported by others (Nature 2000, 404:892-897), the role of NF-κB in PAH-induced apoptosis and cell transformation is not clear (supported by NCI grant 1R15CA125630). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5551. doi:10.1158/1538-7445.AM2011-5551

Carbocations

AbstractThe role of quantum calculations in the field of carbocations is reviewed mainly over the past 10 years. The importance of structure and energy is emphasized. New nuclear magnetic resonance results in solution and infrared spectra in the gas phase give structural insights when coupled with theory. A critical review of applications of popular theoretical methods to the prediction of hydrocarbon and carbocation energies is presented, showing where problems can be anticipated, particularly for density functional theory methods. Gas‐phase stabilities of carbocations are discussed along with the interpretation of their hydride ion affinities in terms of the fundamental factors that determine stability: polarization, inductive, ring‐strain, hybridization, hyperconjugation, conjugation, and aromaticity/antiaromaticity effects. Interesting new carbocation structures and new bifurcation mechanisms are featured, along with examples of the role of carbocations in petroleum chemistry and zeolite catalysis, environmental chemistry and carcinogenic polynuclear aromatic hydrocarbons, and the biosynthesis of terpenes. In all of these areas, theoretical calculations often lead the way, filling experimental gaps that can lead to proper interpretation of experiments, providing insights that lead to a fundamental understanding of experimental results, and making new predictions of unexpected structures, properties, and reaction mechanisms for carbocations. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 487–508 DOI: 10.1002/wcms.12This article is categorized under: Structure and Mechanism > Molecular Structures Electronic Structure Theory > Ab Initio Electronic Structure Methods Electronic Structure Theory > Density Functional Theory

Inefficient Nucleotide Excision Repair in Human Cell Extracts of the N-(Deoxyguanosin-8-yl)-6-aminochrysene and 5-(Deoxyguanosin-N2-yl)-6-aminochrysene Adducts Derived from 6-Nitrochrysene

Ubiquitous environmental agents [e.g., polynuclear aromatic hydrocarbons (PAHs) and their nitrated derivatives (NO(2)-PAHs)] that are known to induce mammary cancer in rodents are regarded as potential human risk factors for inducing analogous human cancers. Although 6-nitrochrysene (6-NC) is less abundant than other NO(2)-PAHs in the environment, it is the most potent mammary carcinogen in the rat; its carcinogenic potency is not only higher than that of the carcinogenic PAH, benzo[a]pyrene (B[a]P), but also of the well-known carcinogenic heterocylic aromatic amine, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). Studies in rats and in vitro assays have indicated that 6-NC can be activated by simple nitroreduction leading to the formation of 6-hydroxylaminochrysene (N-OH-6-AC); this metabolite yielded N-(deoxyguanosin-8-yl)-6-aminochrysene (N-[dG-8-yl]-6-AC) and 5-(deoxyguanosin-N(2)-yl)-6-aminochrysene (5-[dG-N(2)-yl]-6-AC. These lesions are likely to cause mutations if they are not removed by cellular defense mechanisms before DNA replication occurs. However, nothing is known about the susceptibility of these adducts to nucleotide excision repair (NER), the major cellular repair system that removes bulky adducts. In order to address this issue, we synthesized the N-(dG-8-yl)-6-AC and 5-(dG- N(2)-yl)-6-AC lesions and site-specifically inserted these lesions into 135-mer DNA duplexes. These constructs were incubated with NER-competent nuclear extracts from human HeLa cells. The efficiency of repair of these lesions was ∼ 8 times less efficient than that in the case of the well-known and excellent substrate of NER, the intrastrand cross-linked cis-diaminodichloroplatinum II adduct in double-stranded DNA (cis-Pt), but similar to N(2)-dG adducts derived from the (+)-bay region diol epoxide of B[a]P [(+)-trans-B[a]P-N(2)-dG]. The results support the hypothesis that the N-(dG-8-yl)-6-AC and 5-(dG-N(2)-yl)-6-AC lesions may be slowly repaired and thus persistent in mammalian tissue which could, in part, account for the potent tumorigenic activity of 6-NC in the rat mammary gland.

Emissions of Polycyclic Aromatic Hydrocarbons in the Atmosphere: An Indian Perspective

ABSTRACT Organic compounds form a major fraction of airborne particles in the atmosphere and hence it is important to measure and identify them, especially the proportion of Polycyclic (Polynuclear) Aromatic Hydrocarbons (PAHs). The control and abatement of PAHs contamination requires the knowledge of the nature, source, and extent of pollution and hence existing literature on Indian studies was reviewed to gather information on the sources and emission rates of PAHs. Based on the results of the present study along with the data available from literature for particular PAHs in the ambient atmosphere, the vehicular and residential sector was identified as a major source of PAHs emission in many major Indian cities including Ahmedabad, Agra, Delhi, Kanpur, Lucknow, Mumbai, and Nagpur. Emissions of total PAHs range from 23–190 ng/m3, 369–1067 ng/m3, 20.8–100.8 ng/m3, and 12.7–206.4 μg/m3 from gasoline, diesel, petroleum refinery, and biomass, respectively, although it is recognized that this will vary from location to location. Additionally, the regulation and control of PAHs emission, and air quality standards for PAHs were also examined. Based on the toxicity assessment, the study highlights the need to include not only benzo[a]pyrene but also other probable human carcinogenic PAHs while developing a new air quality index for India.

Abstract 3945: Inefficient nucleotide excision repair of the N-(dG-8-yl)-6-AC adduct derived from 6-nitrochrysene, an environmental mammary carcinogen, in human cell extracts

Abstract Ubiquitous environmental agents [e.g. polynuclear aromatic hydrocarbons (PAH), and their nitrated derivatives (NO2-PAH) as well as the food derived heterocyclic aromatic amines (HAA)] that are known to induce mammary cancer in rodents must be regarded as potential human risk factors for inducing analogus human cancers. Although 6-nitrochrysene (6-NC) is less abundant than other NO2-PAH in the environment, it is the most potent mammary carcinogen in the rat; its carcinogenic potency is not only higher than the carcinogenic PAH, benzo[a]pyrene but also of the well-known carcinogenic HAA, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). The presence of bulky DNA adducts in human breast tissues and blood, support the notion that environmental carcinogens play an important role in the etiology of breast cancer. Studies in rats and in vitro assays have indicated that 6-NC can be activated by simple nitroreduction leading to the formation of the corresponding 6-hydroxylaminochrysene (6-NHOH-C); this metabolite yielded three major DNA adducts: N-(dG-8-yl)-6-AC. 5-(dG-N2-yl)-6-AC, N-(dI-8-yl)-6-AC. The second (major) pathway proceeds via a combination of ring oxidation and nitroreduction leading to the formation of 1,2-dihydroxy-1,2-dihydro-6-hydroxylaminochrysene (1,2-DHD-6-NHOH-C); this metabolite yielded 5-(dG-N2-yl)-1,2-DHD-6-AC and N-(dI-8-yl)-1,2-DHD-6-AC. These DNA lesions are likely to cause mutations if they are not removed by cellular defense mechanisms before DNA replication occurs. However nothing is known about the susceptibility of these adducts to nucleotide excision repair (NER), the major cellular repair system that removes bulky DNA lesions. In order to address this issue, we initially synthesized the N-(dG-8-yl)-6-AC lesion and inserted it into 135-mer DNA duplexes. These constructs were incubated with NER-competent nuclear extracts from human HeLa cells. The efficiencies of repair of these 6-NC-derived lesions was compared to the repair of the dG-C8 adduct derived from PhIP. The PhIP-dG-C8 adduct was readily removed by the NER system with efficiencies approaching those of the well-known pyrimidine (6-4) pyrimidone T-T dimer UV photoproduct. In contrast, the N-(dG-8-yl)-6-AC lesion in the identical sequence context was significantly more resistant to repair with 5 - 6 times lower NER efficiencies. These results suggest that the N-(dG-8-yl)-6-AC lesion derived from the metabolic activation of 6-NC may be more persistent in mammalian tissues than the PhIP lesion which may account for the high tumorigenic activity of 6-NC. Support (R01 CA35519). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3945.

Singlet oxygen molecules and carcinogenic aromatic hydrocarbons

Consideration of the possible role of singlet excited oxygen molecules in cell processes offers a promising clue to the point of divergence in the metabolism of carcinogenic and noncarcinogenic polynuclear aromatic hydrocarbons. This hypothesis is supported by quantum-mechanical calculations providing insight into the correlation obtained by Pullman and Pullman between carcinogenic activity and the indices of activity for K and L regions. The method employed is sufficiently general to be used with other classes of chemical compounds, some of whose members show carcinogenic activity.

Determination of polynuclear aromatic hydrocarbons (PAHs) in selected water bodies in the Niger Delta

Several water bodies in the Niger Delta region of Nigeria where extensive crude oil production activities take place were analyzed for the presence of 16 US EPA priority polynuclear aromatic hydrocarbons (PAHs) namely: naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene. The concentrations ranged from as low as 1.95 ug/L for relatively clean stream with practically no crude oil activity to 10.9 ug/L for the most polluted. The analysis was carried out using GC/MS. The quantitation was done by means of internal standardization using four isotopically labeled internal standards namely acenaphthene-d10, chrysene-d12, phenanthrene-d10 and perylene-d12. High molecular mass PAHs such as benzo(ghi)perylene, dibenz(a,h)anthracene and indeno(1,2,3-cd)pyrene were mostly absent confirming low water solubility of these compounds and carcinogenic PAHs were general lower in concentration than the non carcinogenic ones.

Development of an improved analytical method for the determination of carcinogenic polycyclic aromatic hydrocarbons in transformer oil

Polynuclear aromatic hydrocarbons (PAHs) are natural constituents of transformer oils and are essential in prolonging transformer in-service lifetime. Issues concerning PAH carcinogenicity demand methods that provide qualitative and quantitative information on the PAH composition of new and in-service oils to allow informed operational decisions to be made. However, current analytical methods focus on PAH fingerprinting, as opposed to quantitative analysis and are also cumbersome, relying on the use of large (>100 ml) volumes of organic solvents, some of which are hazardous. This paper reports a method for the improved quantification of carcinogenic PAHs in transformer oils that is both simple and repeatable. The method uses commercially available solid-phase extraction columns and millilitre volumes of relatively non-hazardous solvents. Extraction efficiencies of > or =74% were obtained for the Environmental Protection Agency priority PAHs. The method has potential for automation and high-throughput analysis and thus is of interest to industries that use transformer oils.

Respiratory Toxicology of Mineral Oils in Laboratory Animals

Early subchronic and chronic inhalation toxicology studies on various petroleum mineral oils and formulated lubricants supported the ACGIH TLV of 5 mg/m(3) for mineral oil mist. Additional subchronic studies with aerosolized mineral base oils and lubricants during the last 15 years demonstrated that exposures to aerosols of mineral base oils (often >100 mg/m(3)) resulted mainly in concentration-related accumulation in the lung of alveolar macrophages laden with oil droplets. Inflammatory cells were observed with higher aerosol concentrations, consistent with the clinical literature from highly exposed workers. These pulmonary changes appeared to be a nonspecific response to the presence of deposited aerosol. Studies on sensory irritation during exposures of lab animals to mineral oils indicate possible effects only with very high aerosol concentrations. Coupled with changes in refining to remove carcinogenic polynuclear aromatic hydrocarbons from mineral oils several decades ago, this information indicates that current aerosols of mineral oils have a profile of low toxicity from acute to long-term exposures. Available information suggests that additives in some formulated products and/or maintenance of mineral-based metalworking fluids may play a much more significant role in potential health effects.

Incineration: Efficient, Economical, and Environmental

Industries are continually looking for innovative ways to improve air quality and reduce greenhouse gas emission,. Incineration of waste gas products is not a new concept to the oil and gas industry. However in recent years significant improvements in incinerator design and technology have resulted in optimal performance, increased reliability and reduced capital and operating costs.Since the technology has a measurable 99.99% combustion efficiency with no visible flame, black smoke, or detectable odour, petroleum companies are now considering incineration as a cost effective and environmentally responsible alternative to conventional flaring. Incineration is a proven method to reduce greenhouse gas emissions because the global warming potential (GWP) of methane is 21 times greater than the GWP of CO2. Hence. the complete combustion process that incineration offers reduces the global warming effect and significantly improves air quality. Also assisting in reducing greenhouse gas emissions is the fact that incineration requires significantly less fuel gas to combust low heat content streams such as acid or tail gas.Discussion. Incineration allows for the complete combustion of waste gas Streams, where the only emissions exiting the stack to the atmosphere are carbon dioxide and water vapour. Sulphur dioxide also exits the stack when sulphur compounds such as hydrogen sulphide are present in the waste gas stream. Complete combustion is achieved with incineration due primarily to the elevated temperatures reached in the enclosed combustion chamber. In stacks where sufficient temperatures cannot be achieved. Incomplete combustion will result and a variety of by-products are formed that often appear as black smoke and soot particles. From the research conducted by the University of Alberta and the Alberta Research Council, over 250 of these compounds have been identified, some of which are carcinogenic poly-nuclear aromatic hydrocarbons (PAHs). The soot and black smoke occurs most noticeably when the gas is rich (longer chain hydrocarbons), as is the case with solution gas.Flares have difficulty burning efficiently as they do not reach as high a temperature and their performance is adversely affected by cross winds, composition, and entrained liquid droplet size in the waste gas stream. Incineration allows control of lhe combustion process to increase efficiency and optimize the fuel gas consumption. Hence, improving the combustion process by using incineration improves the air quality in the vicinity of oil and gas facilities, as opposed to flaring or venting the waste gas.Incineration Technology. The combustion process within the incinerator results in a thorough mixing of the waste gas stream with sufficient air, followed by the ignition process. The elevated temperatures reached in an incinerator ensure complete combustion of the waste stream.Improvements in incinerator design and technology have resulted in reduced costs and greater reliability. Since the technology has measurable 99.99% combustion efficiency with no visible name black smoke, or detectable odour, petroleum companies are now considering incineration as a cost-effective and environmentally responsible alternative to conventional flaring.These principles are primarily responsible for improved air quality and the reduction in greenhouse gas (GHG) emissions.

Incineration: Efficient, Economical, and Environmental

Abstract Industries are continually looking for innovative ways to improve air quality and reduce greenhouse gas emission,. Incineration of waste gas products is not a new concept to the oil and gas industry. However in recent years significant improvements in incinerator design and technology have resulted in optimal performance, increased reliability and reduced capital and operating costs. Since the technology has a measurable 99.99% combustion efficiency with no visible flame, black smoke, or detectable odour, petroleum companies are now considering incineration as a cost effective and environmentally responsible alternative to conventional flaring. Incineration is a proven method to reduce greenhouse gas emissions because the global warming potential (GWP) of methane is 21 times greater than the GWP of CO2. Hence. the complete combustion process that incineration offers reduces the global warming effect and significantly improves air quality. Also assisting in reducing greenhouse gas emissions is the fact that incineration requires significantly less fuel gas to combust low heat content streams such as acid or tail gas. Discussion Incineration allows for the complete combustion of waste gas Streams, where the only emissions exiting the stack to the atmosphere are carbon dioxide and water vapour. Sulphur dioxide also exits the stack when sulphur compounds such as hydrogen sulphide are present in the waste gas stream. Complete combustion is achieved with incineration due primarily to the elevated temperatures reached in the enclosed combustion chamber. In stacks where sufficient temperatures cannot be achieved. Incomplete combustion will result and a variety of by-products are formed that often appear as black smoke and soot particles. From the research conducted by the University of Alberta and the Alberta Research Council, over 250 of these compounds have been identified, some of which are carcinogenic poly-nuclear aromatic hydrocarbons (PAHs). The soot and black smoke occurs most noticeably when the gas is rich (longer chain hydrocarbons), as is the case with solution gas. Flares have difficulty burning efficiently as they do not reach as high a temperature and their performance is adversely affected by cross winds, composition, and entrained liquid droplet size in the waste gas stream. Incineration allows control of lhe combustion process to increase efficiency and optimize the fuel gas consumption. Hence, improving the combustion process by using incineration improves the air quality in the vicinity of oil and gas facilities, as opposed to flaring or venting the waste gas. Incineration Technology The combustion process within the incinerator results in a thorough mixing of the waste gas stream with sufficient air, followed by the ignition process. The elevated temperatures reached in an incinerator ensure complete combustion of the waste stream. Improvements in incinerator design and technology have resulted in reduced costs and greater reliability. Since the technology has measurable 99.99% combustion efficiency with no visible name black smoke, or detectable odour, petroleum companies are now considering incineration as a cost-effective and environmentally responsible alternative to conventional flaring. These principles are primarily responsible for improved air quality and the reduction in greenhouse gas (GHG) emissions.

Tanker safety and coastal environment: Prestige, Erika, and what else?

such conditions. Even highly sophisticated ships like the German Neuwerk, which arrived in the area on 25 November, had to wait for more favorable conditions. After the crack of the hull, about 20,000 tons of sticky liquid spilled out onto the sea surface. Within the first week, about 2, 000 tons reached Spanish beaches. The PRESTIGE was carrying about 78,000 tons of heavy fuel oil. Most of the oil is still in the sunken vessel. In the beginning , some scientists estimated that the highly viscous cargo would solidify in the freezing depths and stay in the tanks. However, some weeks later, a submarine identified a steady flow of oil out of cracks, gauging and venting outlets with a volume estimated to be more than 100 tons a day. As the behavior of heavy fuel oil in the marine environment is well known and desribed, the associated risks can be estimated. There will be no decay of the gelatonous oil within the tanks. Such products are characterized as having long-chain hydrocarbons, almost no loss by evaporation, almost no water-soluble fraction, a relatively low bioaccumulation potential, but a high persistence in the environment as tar bals or gel slicks. With its viscosity and density properties, it is a persistent, slicky floater on the sea that will ultimately be washed onto the coast. Oily slick will take on up to 4–5 times water and form a 'mousse'. Depending on density, which will change by the evaporation of fumes, separation of water soluble parts and diverse chemical reactions ('weathering'), the slicky slices could submerge and drift below the surface. Similar behavior is estimated for the gel, that is formed under pressure in the cold deep sea. The properties of heavy fuel oils make them considerably more difficult to skim, pump and clean from equipment than lighter oils. Experiences have shown that the use of crane-operated clamshells, buckets or other mechanical grabbers are most effective. Chemical dispersants do not work well, even in calm weather, and at-sea recovery of widely scattered tar balls is not feasable, while at-sea recovery of oil slicks and emulsions is effective and will not require highly-sophisticated ships (O'Brian 2002). The main problem with heavy fuel oil, however, is that the oil is broken into fragments and spread across an area of thousands of square kilometers, with no evaporation. Contaminated with sand it becomes heavier and could drift back into the sea, to surface at a later point in time. Heavy fuel oils cause cancer by prolonged skin contact, because of the high content of carcinogenic polynuclear aromatic hydrocarbons, PAH (Concave 1998). PAH content has been discussed as one of the reasons for genetic damage, reproductive failure and brain lesions in marine populations after the EXXON 1 The Situation

Polynuclear Aromatic Hydrocarbon Concentration and Mutagenicity of Airborne Particles in Urban Air: Comparison of Tokyo Area and Santiago.

Five mutagenic and/or carcinogenic polynuclear aromatic hydrocarbons (PAHs), and Salmonella mutagenicity in airborne particles collected at three stations (industrial, commercial/residential, and agricultural areas) in Santiago, Chile were measured, and compared with the same measurements in the Tokyo metropolitan area. PAH concentrations showed daily variations in both cities. The concentrations of four-ring PAHs were higher in the Tokyo area than in Santiago, and the concentrations of five-or-more-ring PAHs were higher in Santiago than in the Tokyo area. Mutagenic activities also showed daily variations in both places, and were generally higher in Santiago. In the Tokyo area, the mutagenic activities were higher under conditions of TA98-S9 mix than under TA98+S9 mix while in Santiago, the activities were similar under the two mixes. There were good correlations between PAH concentrations and mutagenic activities in both areas. In Santiago, mutagenic activities and PAH concentrations were higher in the commercial/residential area and the industrial area than in the agricultural area.

QUANTIFICATION OF POLYNUCLEAR AROMATIC HYDROCARBONS IN TRANSFORMER OILS BY ENZYME IMMUNOASSAY

Many polynuclear aromatic hydrocarbons (PAHs) are either known or suspected carcinogens and are a common constituent of mineral oils. Due to the large number of possible PAH structures, standard quantification methods fail since they either lack specificity or are too complex, requiring individual fractionation, identification, and quantification. A rapid, low-cost, novel analytical screening method, incorporating a silica-based solid-phase extraction (SPE) method linked to co-solvent dilution and quantification of total and carcinogenic PAH levels by immunoassay, is reported here. The method yielded high extraction efficiencies and minimal matrix effects. This novel approach yielded total and carcinogenic PAH levels × 5.7 and × 126, respectively, lower than that recorded by the industry-recognised BS2000 Pt. 346 (IP346) method which estimates the polyaromatic carbon (PAC) content of oils by gravimetry. The method is expected to be of benefit where an indication of PAH levels in oils is important for purchasing, management or disposal purposes and also for risk assessment and for appropriate labelling of oils in line with current legislation.

Inhibition of CYP1A1-Dependent Activity by the Polynuclear Aromatic Hydrocarbon (PAH) Fluoranthene

Polynuclear aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants, and recently bioassay-based induction studies have been used to determine exposures to complex mixtures of PAHs. Induction of CYP1A1-dependent activity in H4IIE rat hepatoma cells has been used extensively as a bioassay for halogenated aromatic hydrocarbons and more recently for PAHs. Fluoranthene (FL) is a prevalent PAH contaminant in diverse environmental samples, and FL did not induce CYP1A1-dependent ethoxyresorufin O-deethylase (EROD) activity significantly in H4IIE cells. However, in cells cotreated with 2 × 10 −5 M FL plus the potent inducers 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) or benzo[ k]fluoranthene (BkF) (2 × 10 −8 M), there was a significant decrease in EROD activities. Furthermore, treatment of TCDD-induced rat microsomes with FL caused an 80% decrease in EROD activity. Studies showed that FL did not affect induction of CYP1A1 protein or mRNA levels in H4IIE cells, and analysis of enzyme inhibition data using microsomal CYP1A1 indicated that FL noncompetitively inhibited CYP1A1-dependent activity. 32P-Postlabeling revealed no significant FL–DNA adduct formation in H4IIE cells treated with FL. However, in cells cotreated with FL plus BkF or benzo[ a]pyrene (BaP), certain PAH–DNA adducts were induced 2-fold. This study demonstrated that FL is an inhibitor of CYP1A1-dependent enzyme activity in rat hepatoma H4IIE cells and that the genotoxic potency of some carcinogenic PAHs may be modulated by FL in mixtures containing relatively high levels of this compound.

Carcinogenic Polynuclear Aromatic Hydrocarbons in the Atmosphere in Chiang Mai, Thailand.

Ambient concentrations of 7 mutagenic and/or carcinogenic polycyclic aromatic hydrocarbons (PAHs) were measured in Chiang Mai, Thailand, and compared to those in Tokyo. In Chiang Mai, airborne particulate samples were collected at two sites, i.e., commercial and residential sites (two stations in each site) from July through December in 1989. In Tokyo, sampling was carried out at a commercial/residential site in November 1989. PAHs were extracted by sonication, and analyzed by a multicolumn HPLC/computerized fluorometric detection system. Major observations are as follows ; 1) In both cities, ambient concentrations of PAHs and airborne particulates showed log normal distribution. Geometric mean/standard deviation is appropriate to express the situation of pollution. 2) In Chiang Mai, there was not a large difference in PAH concentrations between commercial and residential sites. This suggested wide-spreaded pollution over the city. On the other hand, concentrations of airborne particulates showed large differences among the sites. PAH concentrations in 1989 were higher than those in 1986. 3) Ambient concentrations of PAHs and airborne particulates concentrations were both low in the rainy season and high in the dry season in Chiang Mai. 4) Ambient concentrations of PAHs (except for rather volatile 4 ring PAHs) and airborne particulates in Chiang Mai were suggested to be higher than those in Tokyo. 5) In Tokyo, a fairly good correlation among concentrations of 7 PAHs and airborne particulates has been observed. In Chiang Mai, there has been good correlation among PAHs concentrations, but a poor correlation between PAHs and airborne particulate concentrations. This suggested that large content of rough particulates in Chiang Mai air may be higher than that in Tokyo. These results suggest that air pollution by PAHs and airborne particulates may be more serious in Chiang Mai than in Tokyo. Size distribution of airborne particulates seems to be different between these two cities.

The Changing Cigarette

Background.Epidemiologic surveys have revealed accelerated increases in adenocarcinoma but less rapid increases in squamous cell carcinoma of the lung among cigarette smokers in recent decades. Changes in the makeup of cigarettes and corresponding changes in smoke composition along with nicotine-compensating smoking patterns, such as the frequency of puff drawing and depth of inhalation, are suggested to have contributed to the observed epidemiologic profiles of these major histologic types of lung cancers. Methods.The various changes in cigarette makeup leading to declining smoke yields from sales-weighted averages of 38 mg “tar” and 2.7 mg nicotine to 12 mg “tar” and 0.9 mg nicotine per cigarette are described. Results.Higher nitrate content of tobacco blends is shown to be one of the major influences on lower smoke yields of carcinogenic polynuclear aromatic hydrocarbons (PAH) while causing increased yields of carcinogenic, tobacco-specific N-nitrosamines (TSNA). In vivoand in vitrobioassays incriminate PAH as inducers of squamous cell carcinoma, while TSNA are known to elicit primarily adenocarcinoma of the lung. Conclusions.The product changes, the smokers' dependence on nicotine which governs their smoking patterns, and the modified smoke chemistry support the hypothesis that differences in PAH and TSNA exposure may be linked to the observed different incidences of squamous cell cancer and adenocarcinoma of the lung.