C.-h. Ho

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.

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.

Characterization of insoluble fractions of TNT transformed by composting

Soil contaminated with explosives was supplemented with carbon-14 labelled 2,4,6-trinitrotoluene ([sup 14]C-TNT) and was composted in a field static pile composting experiment. After 90 d of composting, the distribution of carbon-14 ([sup 14]C) activity in fractions from acetonitrile extraction ([open quotes]free[close quotes] fraction, 1.2% of the initial [sup 14]C-activity) and filtration ([open quotes]insoluble-particle[close quotes] fraction, 17.9%), alkaline hydrolysis ([open quotes]insoluble-hydrolyzable[close quotes] fraction, 56.8%), and combustion of the residue ([open quotes]insoluble-nonhydrolyzable[close quotes] fraction, 4.7%) showed that the bulk of the [sup 14]C-activity, and presumably transformed product(s) of the [sup 14]C-TNT, accumulated in a nonextractable, but hydrolyzable fraction. Repetitive aqueous leaching of the compost and also ultraviolet light irradiation followed by leaching suggest that the insoluble fraction of transformed TNT should not be released appreciably by the action of acid rain or sunlight. 16 refs., 11 figs., 2 tabs.

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.

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.

Characterization of Explosives Processing Waste Decomposition Due to Composting

Static pile and mechanically stirred composts generated at the Umatilla Army Depot Activity in a field composting optimization study were chemically and toxicologically characterized to provide data for the evaluation of composting efficiency to decontaminate and detoxify explosives-contaminated soil. Characterization included determination of explosives and 2,4,6,-trinitrotoluene metabolites in composts and their EPA Synthetic Precipitation Leaching Procedure Leachates, leachate toxicity to Ceriodaphnia Dubia and mutagenicity of the leachates and organic solvent extracts of the composts to Ames bacterial strains TA-98 and TA-100. The main conclusion from this study is that composting can effectively reduce the concentrations of explosives and bacterial mutagenicity in explosives -- contaminated soil, and can reduce the aquatic toxicity of leachable compounds. Small levels of explosive and metabolites, bacterial mutagenicity, and leachable aquatic toxicity remain after composting. The ultimate fate of the biotransformed explosives, and the source(s) of residual toxicity and mutagenicity remain unknown.

Short-Term Bioassay of Complex Organic Mixtures: Part II, Mutagenicity Testing

The feasibility of using short-term mutagenicity assays to predict the potential biohazard of various crude and complex test materials has been examined in a coupled chemical and biological approach. The principal focus-of the research has involved the preliminary chemical characterization and preparation for bioassay, followed by testing in the Salmonella histidine reversion assay described by Ames (1). The mutagenicity tests are intended to (a) act as predictors of profound long-range health effects such as mutagenesis and/ or carcinogenesis, (b) act as a mechanism to rapidly isolate and identify a hazardous biological agent in a complex mixture, and (c) function as a measure of biological activity correlating baseline data with changes in process conditions. Since complex mixtures can be fractionated and approached in these short-term assays, information reflecting on the actual compounds responsible for the biological effect may be accumulated. Thus, mutagenicity tests will (d) aid in identifying the specific hazardous compounds involved and in establishing priorities for further valid testing, testing in whole animals, and more definitive chemical analysis and monitoring.

Preparation of oils for bacterial mutagenicity testing

4 procedures used to prepare fossil-derived oils for bacterial mutagenicity testing have been examined. These are, (a) dewaxing by partitioning the oil between dimethyl sulfoxide (DMSO) and cyclohexane, (b) incorporating a surfactant to increase compatibility of the oil with the bioassay media, (c) directly slurrying the oil in DMSO, and (d) computing the mutagenicity of the oil by summing the contributions of individual chemical class fractions. DMSO slurries generally exhibit higher mutagenicities than computed by summing the contributions of chemical class fractions. Results of testing DMSO-slurries correlate (r = 0.87) well, however, with those obtained by summation. Mutagenicity results agree within a factor of two for the samples tested by 4 sample preparation procedures.

Mutagenicity of Nitrogen Compounds from Synthetic Crude Oils: Collection, Separation, and Biological Testing

Short-term mutagenesis assays have been used to test complex environmental mixtures, in order to 1) serve as predictors of long-range health effects, 2) guide chemical separation procedures for the isolation and concentration of biologically active materials, 3) identify chemical agents responsible for biological activity, and 4) determine priorities for further, extensive testing. Organic extraction coupled with chemical-class fractionation is a prerequisite for most of these assays.