PAH Profiles of Charbroiled Hamburgers: Pyrene/B[a]P Ratios and Presence of Reactive PAH

Abstract

Analysis of the polycyclic aromatic hydrocarbons (PAH) in charbroiled hamburgers, used in an earlier study of BaP-DNA adducts in peripheral white blood cells, has been accomplished using HPLC with UV diode array detection. The concentration data for one of these PAH, benzo[a]pyrene (BaP), are in excellent agreement with data obtained using a thin-layer chromatography (TLC)/fluorescence technique. There is significant interest in pyrene/BaP ratios in these samples and other sources of human exposure to PAH since urinary metabolites of both compounds have been used as biomarkers of exposure. In the food samples examined, this ratio is roughly 5. However, differences in cooking procedures between different studies suggest that this value can only be used semi-quantitatively. The BaP concentrations themselves vary by a factor of almost twenty in hamburgers prepared under very similar conditions. Some unstable PAH, including cyclopenteno[cd]pyrene and methylated PAH are found in the hamburger. This possibly reflects their decreased reactivity under conditions different from those which prevail in the outdoor atmosphere.     

BIOALKYLATION OF BENZ(A)ANTHRACENE: IMPLICATIONS FOR CARCINOGENESIS

Previous studies on the metabolic activation of unsubstituted polycyclic aromatic hydrocarbons have largely focused on the formation of oxidation products as a result of reaction of the parent hydrocarbon with microsomal enzymes. These products of reaction have included both epoxide as well as a diol epoxide metabolites. In addition, formation of quinones as well as hydroxyl substituted derivatives of various polycyclic aromatic hydrocarbons have been investigated as metabolic endpoints. Several studies have taken place illustrating the formation of these metabolites, as well as the formation of biologically relevant adducts in a variety of animal models as well as cell culture preparations. Although these metabolic products have been widely characterized and studied in a variety of systems, there have been limited studies characterizing the formation of methyl substituted derivatives of unsubstituted aromatic hydrocarbons, and the subsequent formation of hydroxyalkyl derivatives of various compounds. The present study investigates the formation of both alkyl and hydroxyalkyl substituted derivatives of the unsubstituted polycyclic aromatic hydrocarbon benz(a)anthracene in preparations of rat liver cytosol fortified with S-adenosyl-L-methionine. The results demonstrate that methylated derivatives are formed as metabolic products, and that the identity of these products are both the 7-methybenz(a)anthracene and 7,12-dimethylbenz(a)anthracene. These results confirm that aromatic hydrocarbons undergo biological substitution reactions at specific centers of reactivity of the unsubstituted molecule yielding bioalkylated derivatives.     

Route-Specific Urinary Biomarkers in the Risk Assessment of PAH Exposure

The route of exposure (oral or inhalatory) of the general population to polycyclic aromatic hydrocarbons (PAH) is toxicologically very important. From a literature survey on the toxicity of benzo[a]pyrene (BP) in relation to the route of exposure, it is concluded that although exposure by food is quantitatively the major route of exposure of B[a]P (94%), inhalation exposure is by far more adverse from a toxicological point of view.

Because of the different composition of the PAH mixture in food and air it is possible to distinguish between the route of exposure by monitoring specific metabolites in human urine. Exposure by food and air can be monitored independently by the determination of 1-hydroxypyrene and 1-hydroxynaphthalene in urine, respectively. A very sensitive GCMS method has been developed for urinary 1- and 2- hydroxynaphthalene, which has been applied to urines of non-occupationally exposed smokers and non-smokers. A large difference in urinary concentrations of hydroxynaphthalenes between both groups was observed being a factor 5.9 and 14 for 1- and 2-hydroxynaphthalene, respectively.     

Beyond 16 Priority Pollutant PAHs: A Review of PACs used in Environmental Forensic Chemistry

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soils and sediments, particularly in urbanized environments in which the concentrations of 16 (or so) PAHs are regulated. Distinguishing among the numerous PAH sources is of practical and legal concern and thereby is often an objective of environmental forensic chemistry studies. Studies of prospective sources and impacted soils and sediments that rely upon the 16 U.S. EPA Priority Pollutant PAHs are disadvantaged, as these few compounds generally lack the specificity to distinguish among different PAH sources in the environment. Advances in analytical and interpretive methods over several decades have shown that different PAH sources can be more defensibly distinguished using modified EPA Method 8270 that, among other improvements, measure many other polycyclic aromatic compounds (PACs) that co-occur with the Priority Pollutant PAHs in different sources and in the environment. The PACs include variously-alkylated PAHs and polycyclic aromatic sulfur heterocyclics (PASHs) homologs and individual isomers, which are herein reviewed. Collectively, these PACs provide a higher degree of specificity among PAC sources and can be used to understand the effects of weathering on PAH assemblages. Despite their diagnostic capacity, PACs should not be relied upon at the exclusion of other compound groups (e.g., petroleum biomarkers) in most environmental forensic chemistry studies. In light of these advances, source characterization studies that rely only upon the 16 (or so) Priority Pollutant PAHs warrant considerable caution.     

Development and Analysis of Three Diesel Particulate-Related Standard Reference Materials for the Determination of Chemical,Physical, and Biological Characteristics

The National Institute of Standards and Technology (NIST) has recently issued three Standard Reference Materials (SRMs) related to diesel particulate matter: SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract. These three materials have certified and reference concentrations for selected polycyclic aromatic hydrocarbons (PAHs) including many alkyl-substituted compounds. SRM 1650a is the reissue of an existing material and SRMs 2975 and 1975 represent new materials. The characterization of the PAH content of these three diesel particulate-related SRMs is presented with a discussion of the approach for the certification of PAH concentrations. In addition, the physical and biological characterization of these materials is discussed. A review of customer reported uses of these SRMs in the chemical, physical, and biological sciences is also provided.     

同位素稀释-气相色谱-质谱法同时测定化妆品中20种多环芳烃类化合物

建立了一种同位素稀释-气相色谱-质谱法同时测定化妆品中20种多环芳烃类化合物的方法。不同类型化妆品用环己烷以不同方法进行提取,然后采用GC-MS的选择离子模式对20种目标物进行定性、定量分析。方法具有良好线性,相关系数r均大于0.992,定量限为50μg/kg。各组分平均回收率在70.5%～114.5%,相对标准偏差在1.7%～13.6%。采用此方法测定了化妆品中多环芳烃的水平,发现某些化妆品中存在萘、1-甲基萘和2-甲基萘。     

玩具中有害化学物质的检测研究进展

玩具已成为儿童生活中不可缺少的物品之一。随着玩具中有害化学物质对儿童的健康产生的危害成为社会关注的热点话题,儿童玩具的安全性也逐渐受到重视。儿童玩具中有害物质主要有重金属、增塑剂、多环芳烃及部分有机物等。文章综述了近年来国内外关于玩具中有害化学物质的要求及检测方法的研究进展。     

In Vivo Assessment of the Genotoxicity of PAH-Contaminated Soils in Rats Exposed by Natural Routes

In order to assess the genotoxicity of polycyclic aromatic hydrocarbons (PAHs) in vivo, male laboratory rats were exposed during 4 days to a soil highly polluted with PAHs (1200 mg.kg^?1) obtained from a former coke-plant. A range of dilution, from 1 to 1/8 was realized with sand.

Lymphocytes were sampled every day during the exposure. Injured nuclei were quantified by the technique of Comet assay after inclusion in an agarose gel, cells lysis and electrophoresis migration (modified from [1]).

This study showed an optimum response after three days in fact whatever the dilution degree 95% of the nuclei were injured. The dilution range showed a dose-response relationship. Moreover, the quantity of injured nuclei depended on the duration of exposure. In control animals, less than 5% of the nuclei were damaged at the end of the exposure period.

So the mode of exposure has shown in vivo both the bioavailability and the clastogenicity of PAHs from polluted soils. Therefore, Comet assay can be utilized as a biomarker to evaluate the genotoxic effects of a polluted soil.     

URINARY 3-HYDROXYBENZO[A]PYRENE AS A BIOMARKER OF EXPOSURE TO POLYCYCLIC AROMATIC HYDROCARBONS: AN APPROACH FOR DETERMINING A BIOLOGICAL LIMIT VALUE

Atmospheric and biological monitoring was carried out on 38 people exposed to polycyclic aromatic hydrocarbons in different workplaces. The relationship between the atmospheric BaP and the 3-OHBaP urinary concentration peaks was determined. To avoid misinterpretation due to dermal exposure, only people with mainly respiratory exposure were chosen. The selection was carried out from observation of working conditions and from urinary data. For the limit value determination, BaP concentrations higher than 5,000 ng/m³ were discarded and the 3-OHBaP values were adjusted to a 8 h exposure time. A close relationship was observed between the two variables: n = 17, r = 0.89, p < .0001 (C 3-OHBaP = 0.001835*C BaP + 0.1729). To estimate the 3-OHBaP limit concentration, the French recommended value of 150 ng/m³ for atmospheric BaP was used. The corresponding 3-OHBaP was 0.45 nmol/mol creatinine. This value could be used as a sound basic element for determining a biological exposure index.     

稠环芳烃裂化研究进展

稠环芳烃物种含有大量的芳烃资源,由于苯环间的共轭效应,难以将其直接转化。随着原油芳烃含量的逐年增高,在工业规模如何有效地处理稠环芳烃备受关注。对稠环芳烃的加氢裂化和催化裂化反应机理进行总结对比,并通过介绍裂化催化剂的研究进展为稠环芳烃的催化裂化拓展新思路。     

Activation of PAH by Ozone Derived Oxidants: Results at Ambient Conditions1

Abstract

Particle bound polycyclic aromatic hydrocarbons (PAH) are converted to K-region oxides when exposed to the product stream from a gas phase reaction of ozone and tetramethylethylene (TME). Ozone alone does not give the oxides. Oxide formation requires an oxidant produced in the ozone-TME reaction. Likely candidates for the oxidant are the carbonyl oxide and the dioxirane. In separate experiments it has been shown that dimethyl-dioxirane can react with particulate bound PAH to give K-region oxides. These results support the hypothesis that ozone-alkene reactions in polluted atmospheres may contribute to the formation of mutagens in these atmospheres.     

Ecological Risks Due to Immunotoxicological Effects on Aquatic Organisms

The immunotoxic effects of some anthropogenic pollutants on aquatic organisms are among the causes of concern over the presence of these pollutants in the marine environment. The immune system is part of an organism’s biological defense necessarily for homeostasis. Thus, the immunotoxicological impacts on aquatic organisms are important to understand the effects of pollutant chemicals in the aquatic ecosystem. When aquatic organisms are exposed to pollutant chemicals with immunotoxicity, it results in poor health. In addition, aquatic organisms are exposed to pathogenic bacteria, viruses, parasites, and fungi. Exposure to pollutant chemicals has reportedly caused aquatic organisms to show various immunotoxic symptoms such as histological changes of lymphoid tissue, changes of immune functionality and the distribution of immune cells, and changes in the resistance of organisms to infection by pathogens. Alterations of immune systems by contaminants can therefore lead to the deaths of individual organisms, increase the general risk of infections by pathogens, and probably decrease the populations of some species. This review introduced the immunotoxicological impact of pollutant chemicals in aquatic organisms, including invertebrates, fish, amphibians, and marine mammals; described typical biomarkers used in aquatic immunotoxicological studies; and then, discussed the current issues on ecological risk assessment and how to address ecological risk assessment through immunotoxicology. Moreover, the usefulness of the population growth rate to estimate the immunotoxicological impact of pollution chemicals was proposed.     

Activation of Pah by Ozone Derived Oxidants: Results Using Fly Ash as Particulate [1]

The fly ash bound polycyclic aromatic hydrocarbons (PAH), phenanthrene, pyrene, and cyclopenta[cd]pyrene, are converted to arene oxides when exposed to the products of the gas phase reaction of tetramethylethylene and ozone. These same PAH are also converted to the same oxides when treated with dimethyldioxirane vapors while adsorbed on the fly ash. Exposure to ozone alone does not give oxide formation under the same conditions. Several other PAH fail to give oxides when treated with the tetramethylethylene/ozone product stream. The results support the hypothesis that the products of the ozonolysis of alkenes in polluted atmospheres may be responsible for the activation of PAH in these atmospheres.     

Structure and Photochemistry of Cyclopentene Fused Polycyclic Aromatic Hydrocarbons

Abstract

This review focuses on physico-chemical aspects of cyclopentene-fused polycyclic aromatic hydrocarbons (CPAH) that we are currently studying. Steric effects, deformation of polycyclic skeletons from planarity, radical ions, and excited states are properties being investigated. Molecular modeling as a tool for predicting the geometries of CPAH is discussed.     

Treatment of PAH‐contaminated soil by combination of Fenton's reaction and biodegradation

A combination of modified Fenton and biological treatment was used to remove polycyclic aromatic hydrocarbons (PAHs) from creosote oil‐contaminated soil. After modified Fenton reaction the toxicity of column leachate and soil to Vibrio fischeri increased. The number of intact bacterial cells and utilisation of PAHs in PAH utilisation microplate assay decreased after modified Fenton reaction. However, bacteria in chemically treated soil utilised PAHs without addition of other carbon sources. The activity of extracellular esterases increased during incubation of modified Fenton‐treated soil. PAH removal in combined chemical oxidation and incubation (43–59%) was higher than in incubation alone (22–30%). Residual H₂O₂ in soil allowed chemical oxidation of PAHs during incubation. Copyright © 2006 Society of Chemical Industry     

土壤多环芳烃及其化学氧化修复技术研究进展

多环芳烃作为广泛分布于各类环境介质的持久性有机污染物,在全球环境治理技术研发及应用中备受关注。土壤作为重要的环境介质,在近年来不断发展演变的工业化进程中已成为重要的多环芳烃汇,且储存了环境中超过90%的多环芳烃。从土壤多环芳烃化学氧化技术的角度,阐述了原位/异位氧化修复技术、高锰酸钾、臭氧、芬顿及过硫酸盐氧化技术在近年来的研究进展并进行了展望。     

COMPARISON OF PAHS,NITRO-PAHS AND OXY-PAHS ASSOCIATED WITH AIRBORNE PARTICULATE MATTER AT ROADSIDE AND URBAN BACKGROUND SITES IN DOWNTOWN TOKYO,JAPAN

Atmospheric polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and oxy-PAHs are emitted from primary sources. Some nitro-PAHs and oxy-PAHs can also arise from secondary formation in the atmosphere. To assess the relative importance of these sources, the polycyclic aromatic compound (PAC) concentrations were determined at a roadside (Roadside site) and on a rooftop (Urban Background site) in downtown Tokyo Japan. The concentrations of PAHs, 1-nitropyrene and oxy-PAHs at the Roadside site were higher than those at the Urban Background site, while 2-nitrofluoranthene levels were the same at both sites. However, the mean ratios of concentrations at the Urban Background site to the Roadside site were in the order 1,8-naphthalic anhydride>9,10-anthraquinone>PAHs or 1-nitropyrene or acenaphthenequinone or benzanthrone. This suggests that in addition to vehicle emissions, a considerable fraction of some of the oxy-PAHs studied originates from another source, which might be secondary formation by atmospheric PAH degradation, and this contribution varied among the oxy-PAHs.     

Use of the Semipermeable Membrane Device (Spmd) to Sample Polycyclic Aromatic Hydrocarbon Pollution In A Lotic System

Abstract

Relative concentrations of aqueous polycyclic aromatic hydrocarbons (PAH) were investigated in an urban creek. Samples were obtained at five sites within a 600-m segment of the creek that is critical habitat for an endangered species of fish. the sampling technique entailed immersion of semipermeable membrane devices (SPMDs) in the water for intervals as long as 64 d. SPMDs are passive, in situ, mtegrative samplers of bioavailable (truly dissolved) PAH and other hydrophobic organic contaminants. Two point sources of PAH to the 600-m segment of the creek were differentiated. Aqueous concentrations were found to wane dramatically over the relatively short section of the creek between the point sources. All samples were almost devoid of alkyl-substituted PAH, indicating that the ultimate sources were probably of pyrogenic nature.