Michael R. Guerin

Polycyclic aromatic primary amines as determinant chemical mutagens in petroleum substitutes

Petroleum crude oils and coal- and shale-derived petroleum substitutes have been separated by chemical class and the class fractions have been subjected to bacterial mutagenicity testing. Alkaline constituents of the petroleum substitutes are found to make major contributions to their mutagenicities. High-resolution chromatographic and spectroscopic analysis of alkaline subfractions enriched in mutagenic activity show the causative agents to be polycyclic aromatic primary amines. The amines may be responsible for the increased biological activity of coal- and shale-derived petroleum substitutes relative to petroleum.

Analytical and biological analyses of test materials from the synthetic fuel technologies: IV. Studies of chemical structure-mutagenic activity relationships of aromatic nitrogen compounds relevant to synfuels

Abstract Nitrogen-containing organic compounds from environmental sources are receiving increasing attention because of uniquely active mutagens which have been found in this class (Chrisp et al., 1978; Nagao and Sugimura, 1978; Guerin et al., 1980). Differences in mutagenic activities among the various organo-nitrogen compounds, i.e., pyrrole types, pyridine types and aniline types, have been noted consistently. Furthermore, differences among homologs of a particular compound type are often striking. Information in this paper engages the question of chemical structure/biological activity relationships. Activity data for several N -heterocyclic, nitro-, amino- (primary, secondary and tertiary), and amino- N -heterocyclic aromatic compounds are presented. The number of fused rings and the substituent type affect the mutagenic activities greatly. The trends observed are discussed generally with reference to molecular structural features.

Distribution of mutagenic activity in petroleum and petroleum substitutes

Abstract Several petroleum crude oils and shale- and coal-derived petroleum substitutes have been fractionated by chemical class and the fractions have been tested for mutagenic activity. Crude petroleum substitutes tend to exhibit greater mutagenicities than do petroleum crude oils but the mutagenicity is reduced to comparable levels in low-boiling distillates and samples which have been hydrotreated. The mutagenicity is caused by alkaline and neutral constituents of the petroleum substitutes, but only neutral constituents for the petroleum crudes. The mutagenic components constitute less than ten per cent of the mass of the samples.

Fractionation of synthetic crude oils from coal for biological testing

Abstract A separations procedure that has been used extensively for the reproducible fractionation of cigarette smoke condensate in order to test this material systematically for its carcinogenic properties has been applied to coal liquefaction products. Two types of product oils, one a light oil and the other a heavy tar, have been processed successfully by this procedure. Reproducibility was similar to that reported for condensate fractionations. Proportions, by weight, of fourteen major fractions and some subfractions of the two products were determined. Mutagenicity of the major fractions of the light oil product was tested by microbiological techniques using several strains of Salmonella typhimurium and some mutagenic effect was shown by four of the fractions. The possible carcinogenicity and mutagenicity of the individual fractions are discussed in relation to the reported effects of corresponding cigarette smoke condensate fractions.

Tobacco smoke inhalation studies in rats

Abstract The feasibility of using rats in a bioassay for the effects of fresh tobacco smoke was investigated by a series of acute and long-term inhalation studies. Female SPF rats were exposed to 10% smoke from standard test cigarettes on an intermittent smoke machine. [ 14 C]dotriacontane was used as label for the smoke particles, and it was calculated that under the described exposure conditions 0.3-0.4 mg of total particulate matter was retained in the rats from exposure to the smoke of one cigarette. This is similar to the dose sustained by hamsters under identical conditions. It was found that respiratory minute volume is decreased to 25% of normal during smoke exposure. The great sensitivity of rats to smoke toxicity could be overcome by gradual adaptation. This made it possible to chonically expose rats to 7 and 10 cigarettes per day with a death rate of 10 and 20%, respectively, at 12 months, and of 18 and 53%, respectively, at 18 months of exposure. This represents a far better survival rate at high smoke exposure levels for rats (or hamsters) than has ever been reported in the literature. Smoke-induced pathological changes were observed in the respiratory tract only. These included mild focal hyperplasia of the upper airways, bronchiolitis of the terminal bronchioles, and severe focal alveolitis.

Review of direct MS analysis of environmental samples

Direct sampling mass spectrometry (DSMS) is an increasingly popular technique for rapid and sensitive measurement of organic pollutants in air, water, soil, and wastes. Detection limits are typically in the range of 1 ppb for volatile organic compounds (VOCs in water) with little or no sample preparation required and sample analysis times of less than 3 min. Despite the fast sample analysis time and consequent large sample throughput capability, there are numerous situations that would benefit from the ability to continuously monitor the concentration of targeted VOCs in real time. These include incinerator stack emissions, industrial wastewater streams, chemical process streams, vent emissions, exhaust emissions, groundwater and soil remediation process systems, waste-site off gas during remediation, fugitive emissions, hazardous workplace atmospheres, and soil gas analysis with the use of a dynamic depth profiling probe such as a cone penetrometer. During the past year, several pilot studies have been conducted with a DSMS field instrument for various real-time continuous monitoring applications. These studies have included the monitoring of VOCs in an incinerator stack, monitoring of VOCs in pilot-scale photolytic groundwater remediation systems, measurement of automobile exhaust in a moving vehicle, soil gas measurements in conjunction with a cone penetrometer, and in situ measurement of VOCs in groundwater with the use of a special sampling probe. In each instance, the DSMS instrument was configured with special sampling probes that extracted the VOCs from the sample matrix and transported them through an appropriate transfer line into a direct capillary restrictor interface to the ion trap. Targeted compounds were monitored based on unique peaks in the electron impact and proton transfer chemical ionization mass spectra. The real-time detection limits for VOCs in aqueous systems are in the range of 1 ppb, and in gaseous streams detection limits are in the range of approximately 10 ppb by volume. Temporal resolution ranges up to a maximum of 10 full-scan mass spectra per second, which provides the ability to monitor transient events in a sample stream that might be missed by discrete sample collection and analysis.

Separation of neutral nitrogen compounds from synthetic crude oils for biological testing

Isolation of neutral N-PAHs (PAH homologues containing one or more ring nitrogens) is achieved in three steps using acid-base extraction, gel filtration on Sephadex LH-20, and adsorption chromatography on silicic acid. Gas chromatographic/mass spectrometric analysis of the neutral N-PAH fractions indicated the following as major components: C1-C3 phenylpyrroles, indole, C1-C6 indoles, C1-C3 phenylindoles, carbazole, C1-C5 carbazoles, benzocarbazoles, and C1-C3 benzocarbazoles. The neutral N-PAH fractions were subjected to mutagenicity tests using Salmonella typhimurium/microsomal activation systems devised by Ames. The neutral N-PAH fraction of the coal-derived oil had a specific activity more than twice that of the PAH fraction of the same oil, whereas the shale oil neutral N-PAH fraction showed no activity. These results are discussed in the context of previous work with these oils and with some pure neutral N-PAH compounds.

Separation and Identification of Mutagenic Constituents of Petroleum Substitutes

Abstract A study combining chemical separations, mutagenicity testing, and spectroscopic identifications is underway to isolate and identify mutagens in coal-and shale-derived oils. Ether-aqueous partition combined with Sephadex LH-20 chromatography of the resulting neutral fraction is introduced as a preferred class fractionation procedure. The uniquely important role of polycyclic aromatic primary amines in the mutagenicity of petroleum substitutes is reviewed. Questions are raised concerning the role of polycyclic aromatic hydrocarbons in the mutagenicity of the neutral fraction of petroleum substitutes.

A Tobacco Smoke Inhalation Exposure Device for Rodents

A system which utilizes a piston pump to generate cigarette smoke under standard conditions, and expose rodents to the inhalation of diluted smoke for controlled periods of time is described. Variations of the basic system have been employed to exposure groups of ten to twenty hamsters or rats, and should allow exposures of up to forty mice. The system has been in use for approximately 24 months in routine chronic exposures of rats. Data are presented to define the operating characteristics and typical dosimetry. Animal containment peculiar to this apparatus is described.

Direct analysis of organic compounds in aqueous by-products from fossil fuel conversion processes: oil shale retorting, Synthane coal gasification, and COED coal liquefaction

Abstract Whole water samples are injected directly into a gas Chromatograph equipped with a packed Tenax‐GC column. Polar compounds are separated with good resolution under the temperature programming conditions employed. The by‐product water from oil shale retorting contains carboxylic acids in the homologous series ranging from acetic to decanoic acid. Various amides, cresols and phenol are present in trace amounts. Coal conversion by‐product waters also contain carboxylic acids, but in trace amounts (except acetic). Major components among the dissolved organics in coal conversion samples are phenol, o‐cresol, m‐cresol and p‐cresol. Present at lower levels are several other alkyl substituted phenols and napthols.