John E. Caton

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.

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.

Environmental tobacco smoke in an unrestricted smoking workplace: area and personal exposure monitoring

The objective of this investigation was to determine the extent of areal and day-to-day variability of stationary environmental tobacco smoke (ETS) concentrations in a single large facility where smoking was both prevalent and unrestricted, and to determine the degree of daily variation in the personal exposure levels of ETS constituents in the same facility. The subject facility was a relatively new four-story office building with an approximate volume of 1.3 million ft3. The exchange of outside air in the building was determined to be between 0.6 and 0.7 air changes per hour. Eighty-seven area samples (excluding background) were collected at 29 locations over the course of 6 days of sampling. Locations included offices and cubicles occupied by smokers and nonsmokers, common areas, and the computer and mail rooms. Twenty-four nonsmoking subjects wore personal sampling systems to collect breathing zone air samples on each of 3 days in succession. This generated a total of seventy-two 8-h time-weighted average (TWA) personal exposure samples. In all samples, respirable suspended particulate matter, ultraviolet light-absorbing and fluorescing particulate matter, solanesol, nicotine, and 3-ethenyl pyridine were determined. With the exception of a few locations, tobacco-specific airborne constituents were determined in all samples. Not surprisingly, areas with the highest ETS constituent concentrations were offices and cubicles of smokers. Median and 95th percentile concentrations for all area samples, excluding background, were determined to be 1.5 and 8.7 μg/m3 for nicotine, and 8.2 and 59 μg/m3 for ETS-specific particles (as solanesol-related particulate matter, Sol-PM), respectively. Personal exposure concentrations of ETS components were similar to those levels found in the area samples (median nicotine and Sol-PM concentrations were 1.24 and 7.1 μg/m3, respectively), but the range of concentrations was somewhat smaller. For example, the 95th percentile 8-h TWA nicotine and ETS-specific particle (as Sol-PM) concentrations were 3.58 and 21.9 μg/m3, respectively. Intrasubject variation of daily concentrations ranged from 20% to 60%, depending on the component. Self-reported proximity to smokers was supported by higher ETS concentrations determined from the personal monitors, but only to a modest extent. Although smoking was completely unrestricted inside the main office areas of the facility, ETS levels, either areal or from personal exposure measurements, were lower than those estimated by Occupational Safety and Health Administration to be present in such facilities.

Determination of explosives and some metabolites of TNT in biological and environmental samples by liquid chromatography on a mixed-mode C18-anion column

Abstract This method employs a ternary gradient generated from (1) a 90:10 water:methanol solution that is 0.015 M in potassium phosphate at pH 5.1; (2) methanol; and (3) acetonitrile to separate fifteen explosives, byproducts, and metabolites of 2,4,6-trinitrotoluene (TNT) on a C18/anion exchange stationary phase. TNT, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), six reduction metabolites and three oxidation metabolites of TNT have been separated and quantitated in a single chromatographic run. Because of the anion exchange character of the stationary phase, the anionic TNT metabolite 2,4,6-trinitrobenzoic acid also may be separated and quantitated using this method. Quantitation limits generally lower than 1 ppm have been established by a systematic certification procedure. The performance of the mixed mode separation method combined with diode array ultraviolet absorbance detection has been demonstrated with samples derived from both biological ...

Cigarette smoking by baboons: In vivo assessment of particulate inhalation using bronchoal veolar lavage to recover [14C]dotriacontane☆

In order to demonstrate quantitatively that cigarette-smoking baboons inhale particulate matter into the lung, a bronchoalveolar lavage method for recovery of [14C]dotriacontane was developed. First, 9 baboons were exposed to a known dose of [14C]dotriacontane labeled particulate matter delivered in a manner providing extensive deposition of particulates in the lung. The lungs of these passively exposed animals then were lavaged so that the efficiency of recovery of the standardized lavage procedure could be determined. Second, 9 baboons actively smoked labeled cigarettes, and the lungs of these animals were lavaged to recover labeled [14C]dotriacontane. The total amount of particulate matter present in the lungs was estimated using the efficiency factor previously determined. The smoking baboons retained an average of 9% of he total cigarette particulate matter. Differences among animals in retention of particulate matter were considerable, and the inter-animal variability was related to differences in number, volume, duration, and pressure of puffs. The retention of particulate matter by baboons is similar to particulate retention by other animal smoke inhalation models.

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.

Deposition and distribution of the total particulate matter of cigarette smoke in mice using a large-capacity smoke exposure system☆

A newly developed automatic smoke exposure machine (SEM II) was used to generate [14C]dotriacontane-labeled University of Kentucky reference 2A1 or 2R1 cigarette smoke. The SEM II is a large-capacity (480 mice) dynamic smoke exposure system in which smoke is routed through the animal containment system as a continuously flowing stream. Mice are restrained about the neck in stock-like holders for “nose-only” exposure. Using standard smoke exposure conditions, the deposition and internal distribution of the total particulate matter (TPM) from cigarette smoke was determined in BC3Fl/Cum male and female mice. Results show: (a) smoke exposure conditions can be varied so that deposition from 30 to 200 μg TPM/lung can be obtained, (b) 80–90% of the TPM deposition was found in the respiratory tissues, (c) the mouse-to-mouse variation for TPM deposition in pulmonary tissue was ∼20%, (d) similar deposition and distribution of TPM was observed in male and female mice, and (e) deposition and distribution of TPM was not altered in mice exposed to smoke on a daily basis over a 6-month period of time.

Characterization of Mutagenic Coal Fly Ash and Extracts

Post-electrostatic precipitator (ESP) fly ash samples were collected from a coal-fired electric power generation plant under three modes of plant operation: normal operation, a low NOx-emission mode of combustion, and operation with the ESP shorted-out. Results of chemical and physical characterization of the ashes were compared with bacterial mutagenicity bioassay to determine parameters or compounds correlating with bioactivity. The general physical properties, ultimate composition, and trace elemental and radiochemical species determined did not correlate with the mutagenicity. Only the presence of aromatic hydrocarbons and chemically derivatizable polar organic compounds appeared to be associated with mutagenicity of the fly ash.

A rapid screening procedure for 2-aminonaphthalene in natural, synthetic, and refined crudes

Abstract The mutagen, 2-aminonaphthalene, which is the dominant aromatic amine species in several fossil fuels, may be isolated readily by using a sequential high-performance liquid chromatographic procedure. An initial isolation is achieved on a semi-preparative scale aminosilane column and the final separation is completed with a nonpolar stationary phase column on an analytical scale with a pH-adjusted solvent. The use of fluorescence detection permits discrimination (at least 100-fold) against the nonmutagenic isomer, 1-aminonaphthalene. The overall recovery of 2-aminonaphthalene, as determined by scintillation counting of a radioactive 1-aminonaphthalene tracer, typically exceeds 50% and can reach 92% depending on both the sample matrix and the solubility of the isolate in acetonitrile. The minimum detectable quantity is 0.06 μg g-1 of crude sample.

Determination of hydroxybenzenes in fossil fuel-derived liquids and in associated process waters

Abstract Elution of a nonpolar stationary (reversed)-phase C 18 column with 40% (v/v) acetonitrile in water, buffered with sodium acetate—acetic acid at pH 4.6, produced good resolution of several low-molecular-weight hydroxybenzenes including phenol, o -cresol, m + p -cresol, resorcinol, catechol, and hydroquinone. The unique fluorescent characteristics of hydroxybenzenes enhanced both selectivity and detection limits and facilitated the quantitative estimation of these compounds in a complex mixture after a simple extraction followed by isocratic elution. The determinations can be made within a 24-h period and require small amounts of sample-handling and personnel time. Applications of this scheme to the quantitation of hydroxybenzenes in fossil fuel-derived liquids and associated process waters are described.