Concentrations Of Polycyclic Aromatic Compounds Research Articles

RELATIVE SENSITIVITY OF THREE TERRESTRIAL INVERTEBRATE TESTS TO POLYCYCLIC AROMATIC COMPOUNDS

In a project investigating the ecotoxicity of polycyclic aromatic compounds (PACs), we have previously reported on the sublethal toxicity of eight PACs to springtails (Folsomia fimetaria) and enchytraeids (Enchytraeus crypticus). The model substances included four polycyclic aromatic hydrocarbons (PAHs) and four N-S-O-heterocyclics. Here, new data are presented on the effects of PACs on the survival and growth of the earthworm Eisenia veneta, showing that, in general, earthworm growth was reduced at PAC concentrations above 25 mg/kg soil dry weight. The E. veneta tests were performed using the same soil type and very similar test conditions as for the F. fimetaria and E. crypticus tests, thus providing a good opportunity to compare the sensitivity of these three organisms. Species sensitivity was examined using the 50% reduction in survival (LC50 values) and no-observable-effect concentrations (NOEC values) for growth or reproduction as endpoints. The difference between the least and most sensitive species was generally much larger for LC50 values as compared to the NOEC values, suggesting a higher degree of uncertainty when extrapolating from one species to another for the LC50 data. For the NOEC data, relatively small differences in sensitivity was observed, but as a rather consistent pattern, F. fimetaria was the most sensitive and E. crypticus the least sensitive species. However, one substance (acridine) showed specific toxicity toward E. veneta, which was more sensitive than the two other species by more than one order of magnitude.

Phenolic antioxidants in alder smoke during industrial meat curing

Alder wood smoke in a large sausage-curing chamber was analysed with regard to its content of methoxyphenol antioxidants. The use of Tenax adsorbent cartridges permitted simultaneous quantitative sampling of phenols condensed on smoke particles as well as gaseous compounds. The analytical determinations were performed by thermal desorption combined with gas chromatography and mass spectrometry. In addition to methoxyphenols, several other key components were assessed, including 1,6-anhydroglucose, 2-furaldehyde, furans and hydrocarbons. Benzene was the most prominent hydrocarbon. The concentrations of polycyclic aromatic compounds were low, due to a low smoke generation temperature. Predominant smoke components were the 2,6-dimethoxyphenols, which are characteristic thermal degradation products from hardwood. The 2,6-dimethoxyphenols are stronger antioxidants than the 2-methoxyphenols present in lower amounts. The particularly active antioxidants with a 4-alkenyl side-chain constituted 20–30% of total methoxyphenols, which is much more than normally reported for liquid smoke. The phenolic antioxidants may be important not only for the preservation of foods, but also for health as dietary components.

00/03583 Pyrolysis of oil shales: influence of particle grain size on polycyclic aromatic compounds in the derived shale oils

Oil shales of different particle grain sizes were pyrolysed in a 10 cm diameter x 100 cm high fluidised-bed reactor under both a nitrogen and a steam atmosphere. The oil shales were from the Kimmeridge clay of Jurassic age from the UK. The influence of particle grain size on the yield and composition of the oil and gases was determined. The gases were analysed for H 2 , CO, CO 2 , CH 4 and other hydrocarbons to C 4 . The condensed oils were analysed for their content of polycyclic aromatic compounds (PAC), including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and nitrogen-PAH (PANH). The oil yield increased with increasing particle grain size. The derived shale oils contained significant concentrations of PAH, PASH and PANH. The concentration of PAC increased with decreasing particle grain size. The PAH consisted mainly of naphthalene. fluorene and phenanthrene and their alkylated homologues, and lower concentrations of fluoranthene, pyrene and chrysene. The PASH identified included benzothiophene and dibenzothiophene, and the PANH identified included indole, carbazole and their alkylated derivatives. Increased secondary reactions linked to the formation of PAC were indicated by the alkene/alkane ratio. The effect of steam was to significantly increase the yield of oil and also to increase the concentration of PAH, PASH and PANH in the derived shale oil compared with using nitrogen as the sweep gas.

Evaluation of biomarker variability in fish exposed to polycyclic aromatic compounds at marine sites

Laboratory studies have demonstrated that biliary fluorescent aromatic compounds (FACs) and hepatic polycyclic aromatic compound (PAC)-derived DNA adducts, which measure PAC metabolites, are effective for assessing PAC exposure. In this field validation study, these biomarkers were used to assess PAC exposure in Atlantic croaker ( Micropogonias undulatus), hardhead catfish ( Arius felis), red drum ( Sciaenops ocellatus) and southern flounder ( Paralichthys lethostigma) at sites along the Gulf of Mexico and Atlantic coasts. The biomarker results were compared to PAC concentrations present in sediments. The findings showed that site analyses based on either DNA adducts or biliary FACs had significantly lower coefficients of variation than did the sediment chemistry results indicating these biomarkers were more sensitive in detecting site contamination differences. The low concordance between these three measures observed at some sites could be explained by differences in the toxicokinetics of PAC-DNA adducts and FACs in fish. At sites where multiple species were sampled, species differences were also observed in biomarker responses. In conclusion, the information from the three parameters was needed to assess both the levels of PAC exposure risks experienced by fish and temporal patterns of exposure.

Development of an Analytical Marker for the Prediction of Biological Activity of Bitumen Fumes and Bitumens Using the FIA-DMSO Set-Up. Experimental Set-Up and Correlation with Mutagenicity and Carcinogenicity

During the hot application of bitumen-containing materials, as, for instance, in road paving and roofing, fumes are emitted which contain trace amounts of polycyclic aromatic compounds (PACs). The PAC levels are very low, and from the available epidemiological studies, there is no evidence that human exposure to bitumen or its fumes results in any cancer risk to the workforce. For comparative purposes we are trying to identify a laboratory “marker” for bitumen fume condensates (BFCs) which will give a correlation with biological activity and hence carcinogenic potential. Previously it was found that the determination of total 3–6-ring PACs by DMSO extraction followed by gas chromatographic analysis, whose use is well established for mineral oils, showed promise as a marker for BFCs as well. Because standard DMSO extractions require about 4 g of sample, whereas generally only one mg or less of bitumen fume can be sampled, we developed a micro extraction technique, using Flow Injection Analysis (FIA). The FIA-DMSO extraction was coupled with normal phase liquid chromatography (NPLC) followed by gas chromatography with flame ionisation detection. Only 9 μl of sample solution in cyclohexane (at least 2% m/v) is injected into a cyclohexane stream and extracted with DMSO in the FIA coil. A 50 μl cut from the DMSO stream is introduced into a tetrahydrofurane (THF)/n-octane (50/50) stream to the NPLC-column. A 608 μl fraction of the THF/octane stream after the NPLC column, comprising the time window in which the standard EPA 2–6 ring PAC mixture elutes, is directly introduced into the retention gap. After evaporation of most of the solvent in the retention gap, the concentrated analyte is swept into the GC for the quantitative analysis using the FID. The system is selective towards the biologically most active fraction, the unsubstituted and lightly substituted PACs. The 3–6-ring PAC content by FIA-DMSO correlates well with the Mutagenicity Index (MI) of the Mobil modified Ames test (R2= 0.927), these data have been measured on a wide range of materials ranging from bitumen fume condensates, distillate luboils to heavy residual materials such as bitumens. The residual products have to be freed from the heaviest molecules by pentane precipitation. The 3–6-ring PAC content also correlates with carcinogenicity in mouse skin-painting bioassays. This technique enables us to assess the carcinogenic hazard of potential new feedstocks, processing routes and products in an early stage of development.

Inhalation Study on Exposure to Bitumen Fumes Part 2: Analytical Results at Two Exposure Levels

During the hot application of bitumen-containing materials, e.g. in road paving or roofing, fumes are emitted that contain traces of polycyclic aromatic compounds (PACs). Although worker's exposure to these fumes is low, it might lead to health problems. For studying DNA adduct formation as a consequence of inhalation of bitumen fumes we developed and validated an inhalation system (a dynamic fume generator plus a nose only inhalation chamber). This paper presents and discusses the analytical results from the different laboratories involved in this study on the fumes sampled in the inhalation chamber during three series of experiments where the animals were exposed to fumes at the 5 mg/m3 and 50 mg/m3 level, coming from bitumen heated at 200°C and, as a positive control, fumes from coal tar, heated to 110°C at the 5 mg/m3 level. The following parameters were controlled: temperatures at different key places in the generator; humidity of the chamber; the bitumen or coal tar flow rate; and Total Particulate Matter (TPM). Analyses were performed for Benzene Soluble Matter (BSM), the EPA polycyclic aromatic hydrocarbon (PAH) mixture and for a number of heteroatom-containing PACs. The data show that the coal tar fumes produced at 110°C were very volatile and that most of the differences in particulate matter found between the laboratories can be attributed to evaporative losses. The bitumen fumes boil 25–50°C higher and contain higher boiling compounds. A comparison is made between the PAC exposure profiles for bitumen experiments aimed at 5 and 50 mg/m3. Although the same molecules are found in both fumes their proportion is dramatically different. This effect is largest with the 2- and 3-ring PACs, the ratio of the concentrations found in the 50 mg/m3 TPM concentration to that in the 5 mg/m3 experiment gradually declines from 5500 for acenaphthene to 500 for pyrene, for the 5-ring PACs this ratio is 20–30. As function of their vapour pressure, the ratios of the concentrations of the hetero PACs follow the same trend as that of the 16 EPA PAHs and are of the same order of magnitude. In conclusion, for the compounds investigated, the equipment delivers a fume atmosphere in a reproducible manner. The 50 mg/m3 bitumen fumes are not representatives of field fumes. The reason for these quantitative differences is unclear and further work would be needed to clarify this. Nevertheless it was felt that these fumes at 50 mg/m3 might be a useful tool for qualitative detection of DNA adducts in an animal exposure study. © 2000 British Occupational Hygiene Society. Published by Elsevier Science Ltd. All rights reserved.

Inhalation study on exposure to bitumen fumes Part 2: analytical results at two exposure levels

During the hot application of bitumen-containing materials, e.g. in road paving or roofing, fumes are emitted that contain traces of polycyclic aromatic compounds (PACs). Although worker's exposure to these fumes is low, it might lead to health problems. For studying DNA adduct formation as a consequence of inhalation of bitumen fumes we developed and validated an inhalation system (a dynamic fume generator plus a nose only inhalation chamber). This paper presents and discusses the analytical results from the different laboratories involved in this study on the fumes sampled in the inhalation chamber during three series of experiments where the animals were exposed to fumes at the 5 mg/m3 and 50 mg/m3 level, coming from bitumen heated at 200 degrees C and, as a positive control, fumes from coal tar, heated to 110 degrees C at the 5 mg/m3 level. The following parameters were controlled: temperatures at different key places in the generator; humidity of the chamber; the bitumen or coal tar flow rate; and Total Particulate Matter (TPM). Analyses were performed for Benzene Soluble Matter (BSM), the EPA polycyclic aromatic hydrocarbon (PAH) mixture and for a number of heteroatom-containing PACs. The data show that the coal tar fumes produced at 110 degrees C were very volatile and that most of the differences in particulate matter found between the laboratories can be attributed to evaporative losses. The bitumen fumes boil 25-50 degrees C higher and contain higher boiling compounds. A comparison is made between the PAC exposure profiles for bitumen experiments aimed at 5 and 50 mg/m3. Although the same molecules are found in both fumes their proportion is dramatically different. This effect is largest with the 2- and 3-ring PACs, the ratio of the concentrations found in the 50 mg/m3 TPM concentration to that in the 5 mg/m3 experiment gradually declines from 5500 for acenaphthene to 500 for pyrene, for the 5-ring PACs this ratio is 20-30. As function of their vapour pressure, the ratios of the concentrations of the hetero PACs follow the same trend as that of the 16 EPA PAHs and are of the same order of magnitude. In conclusion, for the compounds investigated, the equipment delivers a fume atmosphere in a reproducible manner. The 50 mg/m3 bitumen fumes are not representatives of field fumes. The reason for these quantitative differences is unclear and further work would be needed to clarify this. Nevertheless it was felt that these fumes at 50 mg/m3 might be a useful tool for qualitative detection of DNA adducts in an animal exposure study.

Development of a carcinogenic potency index for dermal exposure to viscous oil products.

Polycyclic aromatic compounds (PACs) present in oil streams and formulated products are important determinants of possible carcinogenicity. Following dermal exposures the transport of the PACs from oil (the carrier) into the skin is a factor that may affect macromolecular (DNA) adduct formation and thus determine carcinogenicity. We have developed a mathematical model, which describes the flux into the skin for a representative carcinogenic PAC, benzo(a)pyrene. The model is based on measurements of the amount of benzo(a)pyrene bound to skin DNA or blood observed in mouse skin painting studies. The degree of adduct formation from a particular oil product, which we term the Bioavailability Index (BI), was shown to be a function of both the viscosity of the oil product, which affected the transport of the PAC through the carrier, and the aromaticity, which affected the partition of PAC between the carrier and the skin. Literature data were analysed from mouse skin painting studies with mineral oils of known carcinogenicity. A linear relationship was shown between the amount of DNA adduct formation, expressed as alkylation frequency, and the arithmetic product of the total (3-6) ring PAC content and the BI, which we have termed the Carcinogenic Potency Index (CPI). Comparison of literature data on DNA alkylation frequencies for oil products and their carcinogenicity indicated that oils giving rise to an alkylation frequency below a certain threshold (ca. 1 adduct in 10(8) nucleotides) are non-carcinogenic to mouse skin. This threshold level can be translated into a value for the CPI, below which the genotoxic carcinogenic risk arising from skin contact with the oil product is considered to be negligible. The CPI for bitumens is well below this value, being both due to the low BI from bitumen, but more so, due to their low PAC content. For some bitumens diluted with solvents, i.e. cutback-bitumens, the CPI may exceed this value, indicating a possible carcinogenic risk for some of the cutback-bitumens. The main determining factor is the PAC content which is principally determined by the nature of the diluent used.

EFFECTS OF KEROSENE CLEANING ON THE FORMATION OF DNA ADDUCTS IN THE SKIN AND LUNG TISSUES OF MICE DERMALLY EXPOSED TO USED GASOLINE ENGINE OIL

Used gasoline engine oils (UGEO) are carcinogenic and/ or mutagenic in long-term studies and capable of increasing the number of mutagen-or carcinogen-DNA adducts when applied dermally to mice. The carcinogenic or mutagenic risk of UGEO has been attributed to the concentration of polycyclic aromatic compounds (PAC) that accumulate in the lubricating system during combustion of gasoline. When dermal exposure to UGEO takes place, the use of hand cleansers, solvent-or d-limonenebased, is commonly recommended for washing, In this study, female mice aged 4-6 wk (12-17 g) were utilized to evaluate the efficiency of kerosene, as solvent-based cleanser, to remove UGEO following dermal exposure. Using a 32P postlabeling technique, the total levels of DNA adducts in skin and lung were significantly increased in kerosene-treated mice. Application of UGEO followed by kerosene washing significantly decreased skin DNA adduct levels but increased lung adduct levels after 8 h. The observed lower DNA adduct skin levels may reflect greater UGEO skin penetration and absorption in the presence of kerosene cleanser.

Correlation of 32P-postlabelling-detection of DNA adducts in mouse skin in vivo with the polycyclic aromatic compound content and mutagenicity in Salmonella typhimurium of a range of oil products.

The in vivo genotoxic activities in mouse skin of the dimethyl sulphoxide (DMSO) extracts of a range of oil products [residual aromatic extract; untreated heavy paraffinic distillate aromatic extract; mildly refined light naphthenic base oil; bitumen (vacuum residue); high viscosity index base oil obtained by catalytic hydrogenation] were evaluated by 32P-postlabelling DNA analysis. The results of quantitative 32P-postlabelling analyses of epidermal DNA from mice treated with the DMSO extracts showed linear relationships with the total polycyclic aromatic compound (PAC) contents, determined by the Institute of Petroleum method IP 346 and also the 3-6 ring PAC contents, measured by on-line liquid-liquid extraction using flow injection analysis. The 32P-postlabelling data also showed a linear relationship with the mutagenicity indices of these oil products determined in S. typhimurium TA98 using the modified Ames Salmonella microsome test. The in vivo genotoxicity of the DMSO extracts from the oil products was low, judged by 32P-postlabelling analysis of DNA adducts measured in epidermal DNA of treated mouse skin, and ranging from 2 to 723 attomole/microg DNA per mg oil product. The in vivo 32P-postlabelling data from this study are consistent with these materials expressing low genotoxicity in mouse skin in vivo. The DMSO extraction procedure coupled with 32P-postlabelling DNA analysis is useful for ranking the relative genotoxic potency in vivo of a wide range of oil products. In general the trend observed is similar to rankings based on physicochemical measurements of total PAC contents or 3 6 ring PAC contents of the oil products.

Polycyclic Aromatic Compounds in Shale Oils: Influence of Process Conditions

Polycyclic aromatic compounds (PAC) are a significant environmental chemical group, with an associated health hazard. They have been shown to be present in oils derived from the pyrolysis of oil shales; however, the influence of process conditions on their concentration is less well known. Oil shales were pyrolysed in a 200 cm3 stainless steel fixed bed reactor in relation to temperature from 400°C to 620°C in both a nitrogen and nitrogen/steam atmosphere. The condensed oils were analysed for their content of PAC, including polycyclic aromatic hydrocarbons (PAH), sulphur-PAH (PASH) and Nitrogen-PAH (PANH). The derived gases were analysed in terms of H2, CO, CO2, CH4 and other hydrocarbons to C4 and the alkene/alkane ratio determined. The derived shale oils were found to contain significant concentrations of PAH, PASH and PANH some of which have been shown to be biologically active. The main PAH were naphthalene, fluorene and phenanthrene and their alkylated homologues; PASH identified included, benzothiophene, and dibenzothiophene and the PANH included indole, carbazole and quinoline and their alkylated derivatives. The concentration of PAC increased with increasing pyrolysis temperature and their formation was linked to increased secondary reactions as indicated by the gas phase alkene/alkane ratio. The influence of steam was to increase; the yield of oil significantly. The presence of steam also increased the concentration of PAC in the derived shale oil compared to using nitrogen as the sweep gas.

Mutagenic and cytotoxic effects of exhaust particulate matter of biodiesel compared to fossil diesel fuel

The mutagenic and cytotoxic effects of diesel engine exhaust (DEE) from a modern passenger car using rapeseed oil methyl esters (RME, biodiesel) as fuel were directly compared to DEE of diesel fuel (DF) derived from petroleum. Combustion particulate matter was collected on glass fiber filters coated with polytetrafluoroethylene (PTFE) from an exhaust dilution tunnel using three different engine test cycles on a chassis dynamometer. Filters were extracted with dichloromethane in a soxhlet apparatus for 12 h. The mutagenicity of the extracts was tested in the Salmonella typhimurium/mammalian microsome plate-incorporation assay using strains TA97a, TA98, TA100, and TA102. The toxicity to the established cell line L929 (mouse lung fibroblasts) was investigated in the neutral red assay. In the tester strains TA98 and TA100 a significant increase of mutations resulted for the particle extracts of both fuels, but for DF the revertants were significantly higher compared to RME. The highest levels of revertants were observed in tests including a cold start phase. This was probably due to incomplete combustion in the cold engine and a lower conversion rate of the cold catalytic converter. Testing with activated liver S9 fraction induced a slightly lower increase of revertants in most experiments. TA97a and TA102 showed no significant enhancement of spontaneous mutations. In the FTP-75 test cycle RME extracts showed slightly higher toxic effects to the L929 cells than DF, whereas in the other tests no significant differences were observable. These results indicate a higher mutagenic potency of DEE of DF compared to RME. This is probably due to the lower content of polycyclic aromatic compounds (PAC) in RME exhaust, although the emitted masses of RME were higher in most test procedures applied in this study.

A comprehensive evaluation of the mechanism of skin tumorigenesis by straight-run and cracked petroleum middle distillates.

The role of skin irritation and other factors on the tumorigenic activity of petroleum middle distillates (PMDs) in mice was examined in a comprehensive research program. The program culminated in a 2-year dermal carcinogenicity study which compared the effects of equal weekly doses of irritating and nonirritating PMDs. Modified Ames mutagenicity studies and three- to seven-ring polycyclic aromatic compound (PAC) analyses indicated that the mutagenic activity of PMDs was correlated to PAC content. In subchronic and subacute studies, PMDs produced marked skin irritation which was ameliorated if the test samples were diluted in mineral oil. The reduction in irritation level was not a result of reduced dermal absorption. Straight-run kerosine (SRK), straight-run gas oil (SRGO), and catalytically cracked light cycle oil (LCO) were evaluated in the dermal carcinogenicity study. Test materials were applied either undiluted (2x/week) or as 28.5% (7x/week) or 50% (4x/week) concentrations in mineral oil for a total weekly dose of 100 microliters PMD per animal. All three materials produced moderate to marked skin irritation and increased tumor frequency when applied undiluted. When diluted, the irritant effects of SRK and SRGO, which contain low levels of PACs, were ameliorated, and there were no significant increases in tumors relative to controls. LCO, containing 8.7% three- to seven-ring PACs, increased tumor frequency when diluted, even when skin irritation was limited. These data indicate that the tumorigenic activity of straight-run MDs is likely a consequence of a nongenotoxic process, associated with frequent cell damage and repair. PMDs which contain low levels of three- to seven-ring PACs are unlikely to cause tumors in the absence of prolonged skin irritation. In addition, genotoxic mechanisms may also contribute to tumor formation for other PMDs containing higher levels of PACs, e.g., products blended with cracked stocks.

SYSTEMIC TOXICITY OF DERMALLY APPLIED CRUDE OILS IN RATS

Two crude oils, differing in viscosity (V) and nitrogen (N) and sulfur (S) content, were evaluated for systemic toxicity. In the Crude I (low V, low N, low S) study, the material was applied to the clipped backs of rats at dose levels of 0, 30, 125, and 500 mg/kg. In the Crude II (high V, high N, moderate S) study, the oil was applied similarly at the same dose levels. The crude oils were applied for 13 wk, 5 d/wk. Exposure sites were not occluded. Mean body weight gain (wk 1-14) was significantly reduced in male rats exposed to Crude II; body weight gain of all other animals was not adversely affected by treatment. An increase in absolute (A) and relative (R) liver weights and a decrease in A and R thymus weights were observed in male and female rats exposed to Crude II at 500 mg/kg; only liver weights (A and R) were adversely affected in male and female rats exposed to Crude I. In general, there was no consistent pattern of toxicity for serum chemistry endpoints; however, more parameters were adversely affected in Crude II-exposed female rats than in the other exposed groups. A consistent pattern of toxicity for hematology endpoints was observed among male rats exposed to Crude I and male and female rats exposed to Crude II. Parameters affected included: Crudes I and II, red blood cell count, hemoglobin, and hematocrit; Crude II, platelet count. Microscopic evaluation of tissues revealed the following treatment-related findings: Crude I, treated skin, thymus, and thyroid; Crude II, bone marrow, treated skin, thymus, and thyroid. The LOEL (lowest observable effect level) for skin irritation and systemic toxicity (based on marginal effects on the thyroid) for both crude oils was 30 mg/kg; effects were more numerous and more pronounced in animals exposed to Crude II. Systemic effects are probably related to concentrations of polycyclic aromatic compounds (PAC) found in crude oil.

Evaluation of the Dermal Carcinogenic Potential of Re-refined Base Stocks Using the Modified Ames Assay, PAC Analysis and the32P-Postlabeling Assay for DNA Adduct Induction

The standard method for assessing the carcinogenicity of lubricating oil base stocks is the mouse skin-painting bioassay. This assay has the advantage of directly measuring the endpoint of interest, dermal carcinogenicity, but has the drawback of being time-consuming and expensive. For this reason, a variety of biological and chemical assays have been developed as predictive alternatives to the in vivo assay. This publication describes the application of three such methods to the assessment of carcinogenic potential of hydrotreated, re-refined oils: the modified Ames test, the analytical determination of 3-7-ring polycyclic aromatic compound content and the 32P-postlabeling assay for DNA adduct induction.

Evaluation of the dermal carcinogenic potential of re-refined base stocks using the modified Ames assay, PAC analysis and the 32P-postlabeling assay for DNA adduct induction.

The standard method for assessing the carcinogenicity of lubricating oil base stocks is the mouse skin-painting bioassay. This assay has the advantage of directly measuring the endpoint of interest, dermal carcinogenicity, but has the drawback of being time-consuming and expensive. For this reason, a variety of biological and chemical assays have been developed as predictive alternatives to the in vivo assay. This publication describes the application of three such methods to the assessment of carcinogenic potential of hydrotreated, re-refined oils: the modified Ames test, the analytical determination of 3-7-ring polycyclic aromatic compound content and the 32P-postlabeling assay for DNA adduct induction.

Polycyclic aromatic compounds and saturated hydrocarbons in tissues of flatfish: Insight on environmental exposure

The concentration of polycyclic aromatic compounds (PACs) was investigated in muscle, liver and gonad of American plaice and yellowtail flounder collected in the northwest Atlantic. A broader range of PACs was detected in liver than in muscle or gonad of flatfish, including sulphur heterocycles indicative of a source of petroleum hydrocarbons. Lower levels of PACs were observed in ovaries than testes of same size fish and possibly negatively correlated to gonad indices. Different ratios were observed between parental and alkylated PACs, with species, location, tissue or season. The following concentration trend was consistently observed in muscle: NA > C-1NA > C-2NA > C-3NA ≥ C-4NA. Saturated hydrocarbons represented by n-alkanes were analysed in tissues of yellowtail flounder. Muscle and gonads had undetectable concentrations, while livers displayed a fingerprint predominated by biogenic alkanes.

On‐line LC‐GC‐AED and LC‐GC‐MS – multidimensional methods for the analysis of PAC in fuels, combustion emissions and atmospheric samples

AbstractThe composition and concentration of polycyclic aromatic compounds (PAC) in fuels. Theier combustion products and in the atmosphere remains a topic of considerable interest. Despite the wealth of literature on the identification of PAC, speciation at low concentrations remains difficult due to instrument limitation and the complexity of fuel and environmental samples. Consequently on line sample preparation procedures (SPE, SFE, LC, etc.) are becomeing an increasingly important step in the analysis procedure particularly where sample clean‐up and fractionation are essential for improving analytical resolution. In this study a normal phase high pressure analytical resolution. In this study a normal phase high pressure liquid chromatography‐gas chromatography (LC‐GC) system has been developed to provide quantitative analysis of samples, as diverse as coal liquids, petroleum fuels, diesel exhaust particulates, and urban air particulates. Separation and identification of parent and alkylated PAH, hetercycline nitro‐and oxy‐PAC can be achieved by direct coupling to an atomic emission detector and a bech top mass spectrometer. For both systems the primary LC separation combined with the large sample volume transferred to GC vastly improves detection limits. Furthermore the complimentary nature of the two detectors used enables the positive indentification of many unknowns.

Human cell mutagenicity of oxygenated, nitrated and unsubstituted polycyclic aromatic hydrocarbons associated with urban aerosols

Polycyclic aromatic compounds (PAC) are ubiquitous pollutants in urban air that may pose risks to human health. In order to better assess the health risks associated with this class of compounds, a total of 67 PAC that eitheir have been identified (55) or are suspected to be present (12) in urban aerosol samples were tested for mutagenicity in a forward mutation assay based on human B-lymphoblastoid cells. The cell line used (designated h1A1v2) constitutively expressed the cytochrome P4501A1, which is known to be necessary for the metabolism of many promutagens. The PAC tested included 39 polycyclic aromatic hydrocarbons (PAH), 19 oxygen-containing PAH (oxy-PAH) and nine NO 2-substituted PAH (nitro-PAH). A total of 26 PAH were mutagenic. In comparing the minimum mutagenic concentrations of the mutagenic PAH with that of benzo[ a]pyrene (B[ a]P) it was found that dibenzo[ a, l]pyrene (DB[ al]P), cyclopental[ c, d]pyrene (CPP), naphtho[2,1- a]pyrene, dibenzo[ a, e]pyrene (DB[ ae]P) and 1-methylbenzo[ a]pyrene were 24 ± 21, 6.9 ± 4.2, 3.2 ± 3.0, 2.9 ± 2.9 and 1.6 ± 1.4 times, more mutagenic than B[ a]P, and that dibenzo[ a, k]fluoranthene and B[ a]P, and B[ a]P were approximately equally mutagenic. The 19 other mutagenic PAH were between ∼ 2 and ∼ 1800 times less mutagenic than B[ a]P. Of the oxy-PAH tested only phenalenone, 7 H-benz[ d, e]anthracen-7-one, 3-nitro-6 H-dibenzo[ b, d]pyran-6-one, cyclopenta[ c, d]pyren-3(4 H)-one, 6 H-benzo[ c, d]pyren-6-one (BPK) and anthanthrenequinone were mutagenic; however, with the exception of BPK, these were over 50 times less active than B[ a]P. BPK was ∼ 3 times less active than B[ a]P. Seven of the nitro-PAH were mutagenic including 9-nitroanthracene, 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,3-dinitropyrene, 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene. 1,6-DNP was ∼ 4 times less active than B[ a]P; the six other mutagenic nitro-PAH were between 20 and 380 times less active than B[ a]P. These results are discussed in terms of their relevance for determining the most important mutagens in ambient air. Based on reported concentrations of PAC in ambient aerosols, it is possible that CCP, DB[ ae]P, DB[ al]P and BPK could account for a greater proportion of the mutagenicity than B[ a]P in some aerosols.

Accumulation and dose-response of hepatic DNA adducts in English sole ( Pleuronectes vetulus) exposed to a gradient of contaminated sediments

Levels of hepatic DNA adducts and concentrations of fluorescent aromatic compounds (FACs) in bile were measured in English sole ( Pleuronectes vetulus) exposed for up to 5 weeks to a reference sediment amended with a sediment containing high concentrations of polycyclic aromatic compounds (PACs) from Eagle Harbor, Puget Sound, WA. Levels of hepatic DNA adducts increased linearly with both concentration of sediment polycyclic aromatic hydrocarbons (PAHs) and length of exposure, whereas concentrations of biliary FACs were dose-responsive to levels of sediment PAHs but attained steady-state concentrations after 2 weeks of exposure. The levels of DNA adducts and concentrations of biliary FACs in fish exposed to the reference sediment remained at baseline levels throughout the exposure. Formation of PAC-DNA adducts was observed in liver of English sole injected with an extract of Eagle Harbor sediment (EHSE) and in English sole hepatocytes incubated with EHSE or the neutral fraction of EHSE containing predominantly PACs. In addition, DNA adduct and biliary FAC levels measured in feral English sole captured from Eagle Harbor, when compared with levels measured in fish from the laboratory sediment exposure study, also suggested accumulation of DNA adducts in the fish captured from Eagle Harbor. These findings, in conjunction with previous studies showing PAC-DNA adducts are persistent in fish, suggest that a substantial proportion of PAC-induced DNA damage was not readily repaired in English sole, and thus, measurement of hepatic DNA adducts can be used as an indicator of cumulative exposure to genotoxic PACs.