Mutagenic Constituents Research Articles

Reduced levels of biomarkers of exposure in smokers switching to the Carbon-Heated Tobacco Product 1.0: a controlled, randomized, open-label 5-day exposure trial

In addition to smoking cessation, for those who would otherwise continue to smoke, replacing cigarettes with less harmful alternatives can reduce the harms of smoking. Heating instead of burning tobacco reduces, or eliminates, the formation of harmful and potentially harmful constituents (HPHC) that are found in cigarette smoke. The Carbon-Heated Tobacco Product (CHTP), a heat-not-burn tobacco product, mimics the cigarette smoking ritual. This randomized, open-label, two-arm, parallel-group, short-term confinement study tested the hypothesis that the geometric means of the BoExp levels for subjects switching to CHTP 1.0 for 5 days are lower relative to those continuing to smoke cigarettes. Biomarkers of exposure (BoExp), including nicotine, urinary excretion of mutagenic constituents (Ames test), and cytochrome P450 (CYP) 1A2 activity, were measured in blood and/or 24-h urine samples during ad libitum product use. Nicotine exposure remained at similar levels in individuals using CHTP as in those continuing to smoke cigarettes. Switching to CHTP resulted in marked decreases in all other urinary BoExp (56–97%), carboxyhemoglobin (59%), urinary mutagenic constituents, and CYP1A2 activity compared with continued cigarette smoking. Our results provide evidence of decreased exposure to 15 selected HPHCs in smokers switching from cigarettes to exclusive CHTP use.Trial registration ClinicalTrials.gov: NCT02503254; Date of first registration: 20/07/2015 https://www.clinicaltrials.gov/ct2/show/NCT02503254.Study protocol Study protocol published at: https://www.clinicaltrials.gov/ProvidedDocs/54/NCT02503254/Prot_000.pdf.

Exposure to harmful and potentially harmful constituents decreased in smokers switching to Carbon-Heated Tobacco Product

Background“Heat-not-burn” tobacco products are designed to heat processed tobacco instead of combusting it, thus significantly reducing the formation of harmful and potentially harmful constituents (HPHCs) found in cigarette smoke, and ultimately reducing the risk of smoking-related diseases. The Carbon-Heated Tobacco Product (CHTP), a heat-not-burn tobacco product similar in appearance and use ritual to cigarettes, has been developed for smokers who would otherwise continue smoking as an alternative to cigarettes. To evaluate reduced risk of harm potential of CHTP, it is critical to quantify exposure to HPHCs and consequent biological pathway disturbances involved in disease onset in smokers who switch to CHTP. MethodsIn this 2-arm, parallel-group study, adult healthy smokers, not willing to quit, were randomized to switch to CHTP 1.2 (n = 80) or to continue using cigarettes (n = 40) for 5 days in confinement followed by 85 days in an ambulatory setting. Endpoints included biomarkers of exposure (BoExp) to HPHCs, and to nicotine, urinary excretion of mutagenic constituents (Ames assay), CYP1A2 activity, biomarkers of effect, and safety. ResultsIn switchers to CHTP, BoExp were 40%-95% lower compared to smokers after 5 days of product use, with sustained reductions (36%-93%) observed on Day 90. Urine mutagenicity and CYP1A2 activity were also lower in the CHTP group. Exposure to nicotine was higher in the CHTP group at Day 5, but was similar between the two groups at Day 90. Favorable changes in some biomarkers of effect were observed in the CHTP group showing reductions in white blood cell count, soluble intracellular adhesion molecule-1, and 11-dehydro-thromboxane B2, respectively, indicative of reduced inflammation, endothelial dysfunction, and platelet activation. ConclusionsSwitching from cigarettes to CHTP resulted in significantly reduced exposure to HPHCs and was associated with observed improvements in some biomarkers of effect representative of pathomechanistic pathways underlying the development of smoking-related diseases.

Electrospray MS‐based characterization of β‐carbolines – mutagenic constituents of thermally processed meat

The beta-carbolines 1-methyl-9H-pyrido [3,4-b]indole and 9H-pyrido[3,4b]indole have been implicated as having causative roles in a number of human diseases, such as Parkinson's disease and cancer. As they can be formed during the heating of protein-rich food, a number of analytical methodologies have been proposed for their detection and quantification in foodstuff. For this purpose, LC-MS and LC-MS/MS have emerged as the most specific analytical methods, and the quantification is based on the occurrence of unusual ions, such as [M+H-(H(*))]+ and [M+H-2H]+. In this study, we have investigated the formation of these ions by accurate-mass electrospray MS/MS and demonstrated that these ions are formed from gas-phase ion-molecule reactions between water vapor present in the collision cell and the protonated molecule of 1-methyl-9H-pyrido [3,4-b]indole and 9H-pyrido[3,4b]indole. Although this reaction has been previously described for heterocyclic amine ions, it has been overlooked in the most of recent LC-MS and LC-MS/MS studies, and no complete data of the fragmentation are reported. Our results demonstrate that additional attention should be given with respect to eliminating water vapor residues in the mass spectrometer when analysis of beta-carbolines is performed, as this residue may affect the reliability in the results of quantification.

Induction of SCEs in CHL cells by dichlorobiphenyl derivative water pollutants, 2-phenylbenzotriazole (PBTA) congeners and river water concentrates

We recently identified dichlorobiphenyl (DCB) derivatives and 2-phenylbenzotriazole (PBTA) congeners as major mutagenic constituents of the waters of the Waka River and the Yodo River system in Japan, respectively. In this study we examined sister chromatid exchange (SCE) induction by two dichlorobiphenyl derivatives, 3,3′-dichlorobenzidine (DCB, 4,4′-diamino-3,3′-dichlorobiphenyl) and 4,4′-diamino-3,3′-dichloro-5-nitrobiphenyl (5-nitro-DCB); three PBTA congeners, 2-[2-(acetylamino)-4-[bis(2-methoxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2 H-benzotriazole (PBTA-1), 2-[2-(acetylamino)-4-[ N-(2-cyanoethyl)ethylamino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2 H-benzotriazole (PBTA-2), and 2-[2-(acetylamino)amino]-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2 H-benzotriazole (PBTA-6); and water concentrates from the Waka River in Chinese hamster lung (CHL) cells. Concentration-dependent induction of SCE was found for all DCBs and PBTAs examined in the presence of S9 mix, and statistically significant increases of SCEs were detected at 2 μg per ml of medium or higher concentrations. SCE induction of MeIQx was examined to compare genotoxic activities of these water pollutants. According to the results, a ranking of the SCE-inducing potency of these compounds is the following: 5-nitro-DCB ≈ MeIQx > PBTA6 > PBTA-1 ≈ PBTA-2 > DCB. Water samples collected at a site at the Waka River showed concentration-related increases in SCEs at 6.25–18.75 ml-equivalent of river water per ml of medium with S9 mix. The concentrations of 5-nitro-DCB and DCB in the river water samples were from 2.5 to 19.4 ng/l and from 4100 to 18,900 ng/l, respectively. However, these chemicals showed only small contribution to SCE induction by the Waka River water.

Kaempferol, a mutagenic flavonol from Helichrysum simillimum

Helichrysum simillimum is native to South Africa. It is used for the treatment of coughs, colds, fever, infections, headache, and menstrual pain. Extracts of this species showed mutagenic effects in the Salmonella/microsome assay. The aim of this study was to isolate and determine the mutagenic constituents of H. simillimum. Bioassay-guided fractionation of 90% aqueous methanol extracts, using Salmonella typhimurium TA98, led to the isolation of the flavonol kaempferol.

Identification of a new mutagen, 4,4′-diamino-3,3′-dichloro-5-nitrobiphenyl, in river water flowing through an industrial area in Wakayama, Japan

3,3′-Dichlorobenzidine (DCB), which has been assigned as a possible carcinogen to humans (Group 2B) by IARC, is produced as a raw material in the manufacture of polymers and dye intermediates. In our previous paper, we identified DCB as an indirect-acting mutagenic constituent in the water concentrates from the Waka River, which flows through an industrial area in Wakayama, Japan. In this study, we have identified a novel mutagen in the water samples from the Waka River. Organic chemicals in the river water were adsorbed to blue rayon at the site where effluents from chemical plants and a sewage plant were discharged into the river. The adsorbate was highly mutagenic in Salmonella YG1024 in the presence and absence of S9 mix, inducing 440,000 and 170,000 revertants/g blue rayon equivalent, respectively. Two mutagenic fractions, which accounted for 18% and 12% of the total mutagenicity of the water concentrate in YG1024 with S9 mix, were separated by HPLC with a reversed-phase column following Sephadex LH20 column chromatography. Both fractions were further separated by HPLC using reversed-phase columns. On the basis of spectral analysis and co-chromatography using an authentic chemical standard, one mutagen in the former fraction was identified as DCB and one mutagen in the latter fraction was deduced to be a novel chemical, a 5-nitro derivative of DCB (5-nitro-DCB; 4,4′-diamino-3,3′-dichloro-5-nitrobiphenyl). 5-Nitro-DCB showed strong mutagenicity in YG1024 especially with S9 mix, inducing 24,200 revertants/μg. 5-Nitro-DCB was detected in water concentrates in the range from less than detection limit to 6.9 μg/g of blue rayon. DCB was also detected in the range from 13.2 to 104 μg/g of blue rayon. These results demonstrate that Waka River water might be continually contaminated with the indirect-acting mutagens DCB and 5-nitro-DCB as major mutagenic constituents of the river water.

Mutagenic potency of heterocyclic amines in the Drosophila wing spot test and its correlation to carcinogenic potency.

The Drosophila wing spot test is fast and sensitive for detecting somatic mutation and recombination. Nine heterocyclic amines, which had been identified as mutagenic constituents of cooked food by using the Salmonella/mammalian-microsome test system, were orally fed to larvae of the tester strain. All the compounds (Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, IQ, MeIQ, MeIQx, AaC, MeAaC) showed mutagenicity in this system. The reported values of carcinogenic potency in the mouse assay for seven of the nine compounds showed an excellent correlation with mutagenic potency values obtained in the Drosophila assay, but not with those obtained in the Salmonella assay, indicating that the Drosophila short-term test is promising for quantitative pre-screening of potential carcinogens.

Mutagenicity of surface soil from residential areas in Kyoto city, Japan, and identification of major mutagens

To clarify the mutagenic potential of surface soil in residential areas in Kyoto city, surface soil samples were collected twice or three times from 12 sites, and their organic extracts were examined by the Ames/ Salmonella assay. Almost all (>92%) samples showed mutagenicity in TA98 without and with S9 mix, and 8/25 (32%) samples showed high (1000–10,000 revertants/g of soil) or extreme (>10,000 revertants/g of soil) activity. Moreover, to identify the major mutagens in surface soil in Kyoto, a soil sample was collected at a site where soil contamination with mutagens was severe and continual. The soil extract, which showed potent mutagenicity in TA98 without S9 mix, was fractionated by diverse column chromatography methods. Five major mutagenic constituents were isolated and identified to be 1,6-dinitropyrene (DNP), 1,8-DNP, 1,3,6-trinitropyrene (TNP), 3,9-dinitrofluoranthene (DNF), and 3,6-dinitrobenzo[ e]pyrene (DNBeP) by co-chromatography using high performance liquid chromatography and spectral analysis. Contribution ratios of 1,6-DNP, 1,8-DNP, 1,3,6-TNP, 3,9-DNF, and 3,6-DNBeP to total mutagenicity of the soil extract in TA98 without S9 mix were 3, 10, 10, 10, and 6%, respectively. These nitroarenes were detected in surface soil samples collected from four different residential sites in other prefectures, and their contribution ratios to soil mutagenicity were from 0.7 to 22%. These results suggest that surface soil in residential areas in Kyoto was widely contaminated with mutagens and there were some sites where surface soils were heavily polluted. 1,6-DNP, 1,8-DNP, 1,3,6-TNP, 3,9-DNF, and 3,6-DNBeP may be major mutagenic constituents that contaminate surface soil in Kyoto and other residential areas.

Detection of 3,3′-Dichlorobenzidine in Water from the Waka River in Wakayama, Japan

In a previous study, we found that water concentrate from the Waka River, which flows through an industrial area in Wakayama, Japan, showed significant mutagenicity in Salmonella typhimurium YG1024 without a mammalian metabolic system (S9 mix), and 4-amino-3,3′-dichloro-5,4′-dinitrobiphenyl (ADDB) was identified as a major direct-acting mutagenic constituent in the water concentrate. ADDB induced 428,000 revertants/μg in YG1024 without S9 mix, and this activity was 48 times as high as that with S9 mix. In this study, to clarify whether other mutagenic contaminants were present in the river, water concentrates were collected at three sites along the Waka River and examined for mutagenicity by the Ames test using YG1024 and YG1029 with and without S9 mix. All water concentrates showed potent mutagenicity in YG1024 with and/or without S9 mix. ADDB was detected in water concentrate that was extremely mutagenic without S9 mix. An indirect-acting mutagen, which accounted for more than 30% of the total mutagenicity of the water concentrates in YG1024 with S9 mix, was isolated from two extremely mutagenic water concentrates by HPLC separation. On the basis of spectral data and co-chromatography using authentic chemicals, this mutagen was identified as 3,3′-dichlorobenzidine (DCB). DCB showed strong mutagenicity in YG1024 with S9 mix, inducing 5,186 revertants/μg. DCB was detected in water concentrates collected on the other three sampling dates in the range from 15.8 to 28.5 μg/g of blue rayon. These results suggest that Waka River water might be continually contaminated with mutagens, and DCB was thought to be the major mutagenic constituent of the river water.

Mutagenicity of Surface Soils in Urban Areas of Aichi Prefecture, Japan, and Bangkok, Thailand

To clarify the contamination levels of surface soil with mutagens in urban areas of Aichi prefecture, Japan, and Bangkok, Thailand, 60 and 67 surface soil samples were collected in Aichi and Bangkok, respectively, and mutagenicities of the organic extracts from these soil samples were examined in the Ames assay using Salmonella typhimurium (S. typhimurium) TA98 and TA100 with and without a mammalian metabolic system (S9 mix). Most of the soil samples collected in both areas showed mutagenicity in TA98 with and without S9 mix and in TA100 with S9 mix. Thirteen (22%) soil samples collected in Aichi showed high mutagenicity (more than 1000 revertants/g of soil) in TA98 with and/or without S9 mix, and six soil samples induced more than 4000 revertants/g of soil in TA98. Mutagenic potencies of most of the soil samples from Bangkok were moderate (100‐500 revertants/g of soil) or low (less than 100 revertants/g of soil) in both strains with and without S9 mix, and only one sample induced more than 1000 revertants/g of soil in both strains. In the characterization of mutagens, organic extracts of two and one soil samples from Aichi and Bangkok, respectively, were separated on an octadecylsilyl (ODS) column for HPLC, and mutagenicities of the resulting fractions were examined using S. typhimurium YG1024 without S9 mix. For the two soil samples from Aichi, retention times of the distinct mutagenic fractions were similar at 40‐74 min, and especially high mutagenicities were detected in three fractions corresponding to dinitropyrene isomers. In contrast, distinct mutagenicities were detected at retention times of 6‐29 min for the sample from Bangkok, and marked mutagenicity was found in the fraction corresponding to another nitroarene. These results indicate that surface soils in urban areas in Aichi and Bangkok are commonly contaminated with mutagens, but major mutagenic constituents in the surface soils are different.

Human Lymphoblast Mutagens in Urban Airborne Particles

While it is known that urban airborne particles typically contain trace levels of bacterial mutagens and rodent carcinogens, little work has been done to identify chemicals in such particles that can genetically alter human cells. In this paper, we describe the analysis of an organic extract of a Washington, DC, airborne particle sample (SRM 1649) for human cell mutagens. Due to the chemical complexity of the extract, a bioassay-directed fractionation method was used to separate mutagenic constituents into chemically simplified fractions. Mutagenicity testing was done using the h1A1v2 cell line, a line of human B-lymphoblastoid cells that have been engineered to overexpress the human cytochrome P4501A1. Chemical analysis of mutagenic fractions was accomplished using GC−MS and HPLC−UV techniques. Our results indicate that ∼20% of the total mutagenicity the extract was accounted for in two fourth-order fractions that contained ∼3% of the total extract mass. These fractions were composed largely of polycycli...

The Mutagenic Constituents of Rubia tinctorum.

Twenty compounds were isolated from the roots of Rubia tinctorum which are used as a commercial source of madder color. Among these compounds, mollugin (1), 1-hydroxy-2-methylanthraquinone (2), 2-ethoxymethylanthraquinone(11), rubiadin (13), 1,3-dihydroxyanthraqunone (14), 7-hydroxy-2-methylanthraquinone (16), lucidin (17), 1-methoxymethylanthraquinone (18) and lucidin-3-O-primeveroside (19) showed mutagenicity with Salmonella typhimurium TA 100 and/or TA 98. Since the mutagenic compounds isolated are anthraquinone derivatives with the exception of compound 1, structure-mutagenicity relationships of the anthraquinones were also studied. The results suggested that the greatest activity is exhibited by 1,3-dihydroxyanthraquinones possessing methyl or hydroxylmethyl group on carbon 2.

Reactions of selected nucleophiles with 2‐chloropropenal, a mutagenic constituent of softwood kraft chlorination effluent

Abstract2‐Chloropropenal (2‐chloroacrolein), a constituent of softwood kraft chlorination effluent that gives strongly positive results in the Salmonella mutagenicity assay (Ames Test), was reacted with various nucleophiles and the resulting effect on mutagenicity monitored. Nucleophiles such as hydroxide ion and sulfur dioxide (HSO−3, SO3) proved very effective in reducing the mutagenicity of aqueous 2‐chloropropenal solutions. The application of other strong nucleophiles, (glutathione, pyrrolidine and sodium thiosulfate) to 2‐chloropropenal also produced substantial benefits in terms of mutagenicity reduction. Further experimentation revealed that the loss of mutagenicity was not the result of the removal of organically bound chlorine but rather the removal of the ethylenic group in 2‐chloropropenal, possibly as a consequence of undergoing Michael‐type 1,4‐addition reactions with the various nucleophiles. In the treatment of 2‐chloropropenal with alkali (pH 9), additional condensation of the acrolein derivative to a polymer was demonstrated by gel permeation chromatography.

Mutagenic potential of runoff water from soils amended with three hazardous industrial wastes

The bacterial mutagenicity of runoff water from soils contaminated with hazardous industrial waste was monitored for a three-year period using Salmonella typhimurium strain TA98 with and without metabolic activation. The wastes included a wood-preserving waste, a combined American Petroleum Institute (API) separator/slop oil emulsion sludge and a storm-water runoff impoundment waste. The wastes were applied to a Weswood silt loam soil (Fluventic Ustochrept) and a Bastrop clay loam soil (Udic Paleustalf) at a rate of 3.1% (wt./wt.) for the wood-preserving waste and of 4.5% for the two refinery wastes. The results indicate that the runoff water from each of the waste-amended soils contained mutagenic constituents. The maximum specific activity was 783 net revertants per milligram residue, which was induced by the runoff water collected from the storm-water runoff impoundment-amended Weswood soil 360 d after application and assayed with metabolic activation. This sample also yielded the maximum weighted activity of 6,554 revertants per liter of runoff water. The mutagenic activities of the runoff water from all waste-amended soils displayed significant increases through 360 d after application and, in most cases, significant decreases in the samples collected approximately three years after application. The mutagenic activities of the runoff water from the Weswood soil were consistently greater than the activities of the runoff water from the Bastrop soil. These results indicate that three years or more may be required for the mutagenic activity of runoff water to return to background level, and that different soils will differ in their capacities to retain mutagenic chemicals during rainfall events.

The mouse-skin carcinogenicity of a mutagenic fraction from beech wood dusts.

A life-time mouse-skin carcinogenicity assay was conducted using female NMRI mice to evaluate the possible direct carcinogenic activity of a mutagenic fraction isolated from beech wood dusts. The samples of untreated beech wood dusts were extracted with methanol at pH3 and were purified from the inhibitory compounds toxic to bacteria, using silica-gel column chromatography. The fraction obtained after passing through the column was tested for mutagenicity in the Ames assay employing Salmonella typhimurium TA100 in the presence of Aroclor-treated rat-liver-S9. Using acetone as the vehicle, this mutagenic fraction was tested for carcinogenicity on an area of 1-1.5 cm shaved skin of mice on the lower back. The mice were treated with half of each dose, twice a week, for only 3 months. The total doses applied per week were 2.5, 5, 7.5 or 10 g equivalent dust/mouse. No substance was used as promoter. No statistically significant difference was found when the life spans of treated and untreated animals were compared. The observed carcinogenic effect was based on tumours and lesions found only on the site of application of the test material. Of 210 mice (effective number, 129) serving as the negative controls, three developed skin lesions but no tumours. Of 280 treated animals (effective number, 188) 34 developed different types of tumours and 20 had a uniform type of precancerous skin lesion. Of 34 tumours observed 21 were originated from the skin, 12 from the mammary glands beneath the site of application, and one was a lymphoma. Comparing the negative controls with the treated animals, the overall carcinogenic effect observed was dose-dependent and statistically significant. Excluding the mammary tumours and a lymphoma found beneath the site of treatment, the overall induction of skin tumours was still significant. However, the dose-dependent increase in the number of skin tumours alone was not statistically significant. These results suggest that beech wood dust contains mutagenic and carcinogenic constituent(s).

The mutagenicity of urine fractions from patients administered antineoplastic therapy

A concern among hospital personnel is their exposure to mutagenic drugs and in the incidental exposures that could occur in caring for the patients. In a recent published study the mutagenicity of urine from patients administered antineoplastic drugs was determined and techniques were developed to chemically inactivate the mutagenicity. A question still remained as to what components of the excreted urine were mutagenic. Urine samples from patients receiving mutagenic drugs were fractionated by high pressure liquid chromatography (HPLC) to then assay by the Ames test the collected and concentrated fractions to determine what were the mutagenic compounds in the urine. Urine samples from patients on single agent cancer treatment with cisplatin, cyclophosphamide, doxorubicin and mitomycin C were assayed. In general, all urine samples containing the cytotoxic agents studied were mutagenic because of the presence of the parent compound, except cyclophosphamide which requires activation and therefore an active metabolite was the major mutagenic constituent in the urine sample. This data indicates that the mutagenicity of urine from patients receiving these antineoplastic agents is the result of the parent compound or a single major metabolite.

A fraction of beech wood mutagenic in the Salmonella/mammalian microsome assay.

Base-pair substitution mutagens were isolated from the dusts of several untreated samples of beech wood and tested for mutagenicity in the Salmonella/mammalian microsome assay. These compounds reverted Salmonella typhimurium his- TA 100 in the presence of Aroclor-induced rat S9. These mutagens were found to be toxic to the cells when tested in a histidine-rich medium (complete medium). Mutagenicity of the non-fractionated wood-dust extracts due to the presence of some inhibitory compounds of wood could not be confirmed significantly. These inhibitors counteracted the reversion of bacteria when the known mutagens, such as benzo(a)pyrene, aflatoxin B1 and ethyl methanesulfonate, were tested. The results indicate that beech wood-dust contains mutagenic constituent(s) which may contribute to their assumed tumor bearing effects among wood-workers.

Screening complex hazardous wastes for mutagenic activity using a modified version of the TLC/Salmonella assay

10 complex hazardous wastes were tested for mutagenic activity using a modified version of the TLC/Salmonella assay developed by Bjørseth et al. (1982). This fractionation/bioassay scheme couples thin-layer chromatography (TLC) with the Salmonella/mammalian-microsome (Ames) assay for the detection of mutagenic constituents in complex mixtures. Crude (unadulterated) hazardous wastes and selected hazardous waste extracts were fractionated on commercially available cellulose TLC plates. Mutagenicity testing was performed in situ by applying a single overlay of minimal growth agar, tester strain TA98 or TA100, and the optional metabolic activation system directly onto the developed chromatogram. A mutagenic effect was indicated either by the appearance of localized clusters of revertant colonies or by an increase in total revertant growth vis-à-vis control plates. 7 of 10 hazardous wastes (including tars, emulsions, sludges, and spent acids and caustics) demonstrated mutagenic activity when tested by this method. To assess the sensitivity of the modified TLC/Salmonella assay, 14 Salmonella mutagens from a wide range of chemical classes and polarities were tested. Selected compounds included heterocyclics, aromatic amines, alkylating agents, antitumor agents, a nitrosamine and a nitroaromatic, 11 of the 14 mutagens were positive in this test system. The 3 compounds refractory to analysis included a polycyclic aromatic hydrocarbon and two volatiles.

Genetic monitoring of aluminum workers exposed to coal tar pitch volatiles

A group of 50 workers exposed to coal tar pitch volatiles (CTPV) in an aluminum reduction plant and a group of 50 non-exposed workers were selected to evaluate the genotoxic effects of CPTV exposure. A battery of tests was performed on 3 different body fluids; urine, blood and semen. Urine samples were evaluated for mutagenic constituents using the Ames/Salmonella assay. Cultured lymphocytes from blood samples were used to perform cytogenetic analysis. Semen samples were used to measure sperm count, percent abnormal sperm morphology and frequency of sperm carrying double fluorescent bodies (2-F). 14 of 28 (50%) exposed workers and 7 of 36 (19.4%) non-exposed workers had mutagenic urine. This difference was significant ( p < 0.01). Among the non-smokers a significantly higher percentage of workers who were exposed had positive urine (36%) compared to the non-exposed workers (5%) ( p < 0.05). Among the exposed group, more mechanics had mutagenic urine than did other types of workers. Overall chromosome aberration rates were similar in both exposed and non-exposed workers. Among exposed workers a significant inverse correlation ( p < 0.05) between age and chromatid aberration rate was observed. Results of semen analysis failed to detect differences between exposed and non-exposed workers. Results of these tests lend support to a battery approach to genetic monitoring and suggest a link between exposure to CTPV and genotoxic effects. Detection of exposure to mutagens at an early time offers an opportunity for disease prevention by the reduction of exposure.

Mutagenicity of the fractionated organic emissions from diesel, cigarette smoke condensate, coke oven, and roofing tar in the ames assay

Mobile and stationary combustion sources emit particle-bound organics that, after extraction, are mutagenic to Salmonella typhimurium. In this study, the organic emissions from diesel, cigarette smoke condensate (CSC), coke oven, and roofing tar were fractionated and compared for mutagenicity in the Ames assay. This study demonstrated major differences in the distribution of mutagenicity among the four emission sources. Within each source, the relative mutagenicity of each fraction was significantly different in the presence and absence of an exogenous metabolic activation. In the diesel sample, over 90% of the mutagenic activity is located in the aromatic and polar neutral (PN) fractions; nitrated polynuclear aromatic hydrocarbons (NO2-PNAs) can account for a significant portion of this activity. Most of the mutagenicity of the coke oven main sample was found in the organic base (BASE) and PN fractions, which contained aromatic amines and nitrogen heterocycles. The CSC sample also had a high percentage of the mutagenic activity in the BASE fraction. Chemical analysis, however, indicates that the components in the CSC differed from those of the coke oven main sample. The roofing tar sample, which was not mutagenic in the absence of metabolic activation, contained several components that were very mutagenic after fractionation. This may be due to the separation of toxic components from the mutagenic components. The roofing tar emissions contained aromatic and polar mutagenic constituents. Although the specific mutagens in these different sources are not identical, they all cause frameshift mutations and appear to be compounds that could be classified as polycyclic organic matter.