Combining different assays and chemical analysis to characterize the genotoxicity of waters impacted by textile discharges

Waters receiving textile discharges can exhibit genotoxic and mutagenic activity, which has been related to the presence of dyes and aromatic amines as synthesis precursors or byproducts. The aim of this study was to identify dyes and aromatic amines in water samples impacted by textile discharges, and to evaluate the genotoxic responses of these samples using the Salmonella/microsome assay in strains TA98 and YG1041, and the Fpg‐modified comet assay in the RTL‐W1 fish cell line. The genotoxicity of river samples downstream of the discharge was greater than the upstream samples in both of the Ames tests. The Fpg‐modified comet assay detected similar levels of DNA damage in the upstream and downstream samples. Mutagenicity was not detected with TA98, except for the Quilombo River samples, but when YG1041 was used as the tester strain mutagenicity was detected for all sites with a very different profile in upstream sites relative to the other sites. The mutagenic response strongly indicated that aromatic amines or dyes were contributing to the mutagenic activity downstream. The impact of textile discharges was also confirmed by chemical analysis, because the highest concentrations of azo dyes and aromatic amines were detected in the river downstream. This study shows the value of combining assays measuring complementary endpoints to better characterize the mutagenicity of environmental samples, with the advantage that this approach provides an indication of what classes of compounds are responsible for the effect. Environ. Mol. Mutagen. 57:559–571, 2016. © 2016 Wiley Periodicals, Inc.     

A promising Ames battery for mutagenicity characterization of new dyes

When testing new products, potential new products, or their impurities for genotoxicity in the Ames test, the quantity available for testing can be a limiting factor. This is the case for a dye repository of around 98,000 substances the Max Weaver Dye Library (MWDL). Mutagenicity data on dyes in the literature, although vast, in several cases is not reliable, compromising the performance of the in silico models. In this report, we propose a strategy for the generation of high‐quality mutagenicity data for dyes using a minimum amount of sample. We evaluated 15 dyes from different chemical classes selected from 150 representative dyes of the MWDL. The purity and molecular confirmation of each dye were determined, and the microplate agar protocol (MPA) was used. Dyes were tested at the limit of solubility in single and concentration‐response experiments using seven strains without and with metabolic activation except for anthraquinone dyes which were tested with eight strains. Six dyes were mutagenic. The most sensitive was YG1041, followed by TA97a > TA98 > TA100 = TA1538 > TA102. YG7108 as well as TA1537 did not detect any mutagenic response. We concluded that the MPA was successful in identifying the mutagenicity of dyes using less than 12.5 mg of sample. We propose that dyes should be tested in a tiered approach using YG1041 followed by TA97a, TA98, and TA100 in concentration‐response experiments. This work provides additional information on the dye mutagenicity database available in the literature.     

Identification of mutagens in freshwater sediments by the Ames-fluctuation assay using nitroreductase and acetyltransferase overproducing test strains

Extracts of sediments from an area of concern in the Elbe river basins (Spittelwasser creek) were analyzed with the Ames-fluctuation test and in parallel with gas chromatography/mass spectrometry for compound identification. The standard test strains TA 98 and TA 100 showed mutagenicity mainly in medium-polar fractions of the sediment extracts. PAHs contribute to the overall mutagenic potential of the sample. Especially, cyclopenta[c,d]pyrene that was previously not defined as a priority hazardous substance has to be considered as well. The addition of metabolically competent test strains, which overexpress nitroreductase and acetyltransferase (e.g., YG1041 and YG1042) to the test battery, increased significantly the sensitivity of the Ames test for medium polar to polar genotoxins. The increased mutagenicity that was found in these bacterial strains indicates the presence of nitroarenes and/or aromatic amines. In fact, a number of heterocyclic and nitrogen-substituted aromatic compounds were identified in the sediments of the Spittelwasser creek of which methyl parathion, 1-naphthylamine, and N-phenyl-2-naphthylamine are mutagenic.     

Mutagenicity of two 2-phenylbenzotriazole derivatives, 2-[2-(acetylamino)-4-(diethylamino)-5-methoxyphenyl]-5-amino- 7-bromo-4-chloro-2H-benzotriazole and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole and their detection in river water in Japan

We recently detected five 2-phenylbenzotriazole (PBTA)-type mutagens (PBTA-1, PBTA-2, PBTA-3, PBTA-4 and PBTA-6) in concentrates from several rivers that flow in geographically different areas in Japan containing textile-related industries. On the basis of synthesis studies, these five PBTA derivatives were deduced to have originated from the corresponding dinitrophenylazo dyes, which are industrial chemicals used in textile dyeing, via reduction and chlorination. 2-[(2-Bromo-4,6-dinitrophenyl)azo]-5-(diethylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 291, CAS registry no. 56548-64-2) and 2-[(2-bromo-4,6-dinitrophenyl)azo]-5-(diallylamino)-4-methoxyacetanilide (Color Index name Disperse Blue 373, CAS registry no. 51868-46-3) are used in textile dyeing and have 2-[(2-bromo-4,6-dinitrophenyl)azo]-4-methoxyacetanilide moieties in their structures, which are thought to be essential for their conversion to mutagenic PBTA derivatives. In the present study we have synthesized 2-[2-(acetyl-amino)-4-(diethylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-7) and 2-[2-(acetylamino)-4-(diallylamino)-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-8) from Disperse Blue 291 and Disperse Blue 373, respectively, by reduction with iron powder and subsequent chlorination with sodium hypochlorite. Both PBTA-7 and PBTA-8 exerted strong mutagenicity in Salmonella typhimurium TA98 and YG1024 in the presence of S9 mix (43 000 and 1 430 000 revertants/nmol for PBTA-7 and 40 700 and 2 213 000 revertants/nmol for PBTA-8 in TA98 and YG1024). To clarify whether PBTA-7 and PBTA-8 exist in the environment, water samples were collected at seven sites in six rivers flowing through two different regions where textile dyeing industries are located. All water samples were mutagenic in Salmonella typhimurium YG1024 with S9 mix and their potencies ranged from 108 000 to 1 990 000 revertants/g blue rayon. PBTA-7 and PBTA-8 were detected in water samples from both regions at levels of <0.1-101.4 ng/g blue rayon and <0.1-48.9 ng/g blue rayon, respectively. In some samples PBTA-7 and PBTA-8 could contribute up to 15% of the water mutagenicity.     

Mutagenicity of blue rayon extracts of fish bile as a biomarker in a field study

Blue rayon (BR) in combination with the Salmonella/microsome assay was used to evaluate the mutagenicity of fish bile samples. Specimens of Mugil curema from two sites were collected over a 1‐year period. Piaçaguera channel contains high concentrations of total polycyclic aromatic hydrocarbons (PAHs) and other contaminants, while Bertioga channel was considered the reference sites in this study. Bile was extracted with BR and tested with TA98, TA100, and YG1041 strains with and without S9 in dose response experiments. PAH metabolite equivalents were analyzed using reverse‐phase high performance liquid chromatography /fluorescence. Higher mutagenic responses were observed for the contaminated site; YG1041 with S9 was the most sensitive strain/condition. Mutagenicity ranged from 3,900 to 14,000 rev./mg at the contaminated site and from 1,200 to 2,500 rev./mg of BR at the reference site. The responses of YG1041 were much higher in comparison with the TA98 indicating the presence of polycyclic compounds from the aromatic amine class that cause frameshift mutation. TA100 showed a positive mutagenic response that was enhanced following S9 treatment at both sites suggesting the presence of polycyclic compounds that require metabolic activation. benzo(a)pyrene, naphthalene, and phenanthrene metabolite equivalents were also higher in the bile of fish collected at the contaminated site. It was not possible to correlate the PAH metabolite quantities with the mutagenic potency. Thus, a combination of the Salmonella/microsome assay with YG1041 with S9 from BR bile extract seems to be an acceptable biomarker for monitoring the exposure of fish to mutagenic polycyclic compounds. Environ. Mol. Mutagen., 2010. © 2009 Wiley‐Liss, Inc.     

Prostaglandin H synthase-dependent genotoxicity of 2,4-diaminotoluene.

2,4-Diaminotoluene (2,4-DAT), a high volume synthetic compound, is moderately carcinogenic to rodents. We report here that 2,4-DAT is a substrate for the peroxidase activity of prostaglandin H synthase (PHS). In contrast to many aromatic amines which are activated as mutagens by PHS, we find that 2,4-DAT is not mutagenic to six S. typhimurium strains with this activation system. The strains tested include YG1006, YG1024, and YG1029, which are far more sensitive to the mutagenicity of aromatic amines and nitroarenes than are the standard tester strains. Although not mutagenic itself, 2,4-DAT does enhance the mutagenicity of 2-aminofluorene (2-AF) in the PHS-catalyzed system in strains TA98, YG1006, and YG1024, with maximal enhancement of 140%, 1831%, and 1216%, respectively. Half-maximal enhancement of 2-AF mutagenicity is observed at 15-20 microM 2,4-DAT for strains YG1006 and YG1024, and about 80 microM for TA98. Studies with compounds structurally related to 2,4-DAT revealed enhancement of 2-AF mutagenicity with 2,5-DAT and o-phenylenediamine (o-PD) but not for other DAT isomers, toluidines, and phenylenediamines. Maximal enhancement of 2-AF mutagenicity observed in TA98 with PHS-catalyzed activation was 110% for o-PD and 60% for 2,5-DAT. This comutagenic effect of 2,4-DAT appears quite specific for 2-AF, as it fails to enhance either the PHS-dependent mutagenicity of the aromatic amines benzidine and 2-naphtylamine, or the direct mutagenicity of N-acetoxy-acetylaminofluorene,2-nitrofluorene,4- nitroquinoline-N-oxide and 1,1,1-trichloropropene-2,3-oxide. Enhancement of 2-AF mutagenicity by 2,4-DAT is also observed with cytochrome P-450-dependent activation, however the half-maximal 2,4-DAT concentration was 400 microM, and the maximal enhancement was only 50%. The ability of 2,4-DAT, under conditions where it is not itself mutagenic, to enhance the genotoxicity of the potent carcinogen 2-AF comprises an intriguing toxicological interaction, and underscores the inherent difficulties in assessing the genotoxic risks posed by mixtures of compounds.     

Evaluation of laser dye mutagenicity using the ames/salmonella microsome test

Twenty-five laser dyes and four analogs were tested for mutagenicity in the Ames/Salmonella test. Seven dyes and two analogs gave positive mutagenic responses with bacterial strains TA1538 and TA98. Of two widely used families of laser dyes (coumarins and rhodamines), four coumarin samples, but none of the rhodamine samples, were mutagenic. All mutagenic compounds require enzyme activation for positive response except two terphenyl analogs, which are mutagenic with or without activation. Using high-performance liquid chromatography (HPLC), it was determined that five mutagenic dye samples had multiple components. The dyes themselves may not be the mutagenic agents in all cases (as with Nile Blue) but may contain impurities that are mutagenic. One dye, adicyanome-thylene (DCM) (≥95% pure), was mutagenic at doses below 0.5 μg/plate on strains TA1538 and TA98. DCM also induced reversions in strains TA96, TA97, TA100, TA102, and TA104, although less efficiently. This study indicates the need for further toxicological testing of these types of compounds. The mutagenic components of these dye mixtures, whether it is the dye or a contaminant, presents a possible hazard to those handling them. Therefore, practices and procedures for the safe handling of specific dyes should be reviewed in light of these findings.     

Highly sensitive mutation assay for mutagenicity monitoring of indoor air using Salmonella typhimurium YG1041 and a microsuspension method

A highly sensitive mutation assay for indoor mutagenicity monitoringwas investigated by a combination of Salmonella typhimuriumYG strains and the microsuspension method. Tester strains wereYG1024, YG1029, YG1041 and YG1042. YG1041 gave the highest sensitivityin the mutagenicity test for the extracts of airborne particulates.The sensitivity of the microsuspension assay using S.typhimuriumYG1041 in the absence of S9 mix was     

Evaluation of the mutagenicity of azo dyes in Salmonella typhimurium: a study of structure-activity relationships

In order to explore structure-activity relationships, 4,4'-diaminoazobenzene and four structurally related azo dyes were tested for their ability to induce gene mutations in Salmonella typhimurium strains TA1535, TA100, TA1537, TA1538, and TA98. Only 4,4'-diaminoazobenzene and 4,4'-N(beta-hydroxyethylamino)azobenzene were found to be active in the two frameshift strains TA1538 and TA98. Further tests were performed in strain TA98, both in the presence and in the absence of Aroclor 1254-induced rat or hamster liver S9 preparations. The amount of S9 used per plate was 50, 100, 150 or 300 microliters, which corresponds to 10, 20, 30 or 60% of S9 in S9 mix. 4,4'-Diaminoazobenzene was found to be mutagenic, and its mutagenicity depended on the percentage of S9 in S9 mix and the type of S9 fraction used. 4,4'-N-(beta-Hydroxyethylamino)azobenzene was less mutagenic than 4,4'-diaminoazobenzene, indicating a reduction in mutagenicity associated with the beta-hydroxyalkyl substituents. The other three azo dyes [4'-methyl-4-N,N-di(beta-hydroxyethylamino) azobenzene; 4'-amino-6-methyl-4-N,N-di(beta-hydroxyethylamino)azobenzene; and 4'-N(beta-hydroxyethyl-amino)4-N,N-di(beta-hydroxyethylamino)azobe nzene] were inactive, both in the presence and in the absence of the metabolic activation system. The use of the preincubation test did not alter the observed positive or negative response of these compounds. The importance of this finding is that the non-mutagenicity or decreased mutagenicity of these four compounds is predictable on the basis of their chemical structures. These azo dyes, like the non-mutagenic members of series of monocyclic aromatic amines, contain large substituents on one or both of the amino groups of the parent compound, in this case 4,4'-diaminoazobenzene. From our earlier data and the experiments discussed in this paper, we conclude that the study of structure--activity relationships can provide useful information for the prediction and interpretation of mutagenic responses.     

Mutagenicity profile of atmospheric particulate matter in a small urban center subjected to airborne emission from vehicle traffic and sugar cane burning

Atmospheric particulate matter (PM) is genotoxic and recently was classified as carcinogenic to humans by the International Agency for Research on Cancer. PM chemical composition varies depending on source and atmospheric conditions. The Salmonella/microsome assay is the most used mutagenicity test and can identify the major chemical classes responsible for observed mutagenicity. The objective of this work was to characterize the mutagenicity of PM samples from a countryside city, Limeira, Brazil, which is influenced by heavy traffic and sugar cane biomass burning. Six samples of total PM were collected. Air mass backward trajectories were calculated. Organic extracts were assayed using the Salmonella/microsome microsuspension mutagenicity assay using TA98, YG1041, and TA1538, with and without metabolic activation (S9). YG1041 was the most sensitive strain and mutagenicity reached 9,700 revertants per m³ without metabolic activation. Potency for TA1538 was higher than TA98, indicating that this strain should be considered in air mutagenicity studies. The increased response to YG1041 relative to TA98, and the decreased response with S9, suggests that nitroaromatics are the major contributors. Limeira is among the most mutagenic cities in the world. High mutagenicity in Limeira seems to occur when the air mass from the area of sugarcane production is mixed with air from the region impacted by anthropogenic activities such as traffic. An increase in the formation of nitro‐polycyclic aromatic hydrocarbons may result from longer contact time between the aromatic compounds and the atmosphere with high NOx and ozone concentration, although more studies are required to confirm this hypothesis. Environ. Mol. Mutagen. 57:41–50, 2016. © 2015 Wiley Periodicals, Inc.     

Structure-mutagenicity relationships of four amino-imidazonaphthyridines and imidazoquinolines

We tested four isomeric imidazonaphthyridines and one imidazoquinoline compound for mutagenic activity in the Ames/Salmonella mutagenicity assay, using strain TA98 and strain YG1024, an analogue of strain TA98 with elevated O-acetyl-transferase levels. Their potency was related to calculated electronic parameters. Five compounds with a linear arrangement of 3 rings showed a positive response in strain YG1024. Compound 2 (1-methyl-imidazo[4,5-b][1,7]naphthyridin-2-amine) is the most mutagenic in both strains, giving specific activities of about 200 and 30 revertants per microgram in strains YG1024 and TA98, respectively. Three of the compounds were weak mutagens, giving a positive dose-response only in strain YG1024, with 3–5 revertants per microgram. A higher response of all five compounds in strain YG1024 as opposed to TA98 indicates that they require O-acetyltransferase activity for their metabolism. Mutagenic potencies in strain YG1024 were positively correlated to the energy of the LUMO (lowest unoccupied molecular orbital) of the nitrenium ion. © 1995 Wiley-Liss, Inc.     

Mutagenicity of an aged gasworks soil during bioslurry treatment

This study investigated changes in the mutagenic activity of organic fractions from soil contaminated with polycyclic aromatic hydrocarbons (PAHs) during pilot‐scale bioslurry remediation. Slurry samples were previously analyzed for changes in PAH and polycyclic aromatic compound content, and this study examined the correspondence between the chemical and toxicological metrics. Nonpolar neutral and semipolar aromatic fractions of samples obtained on days 0, 3, 7, 24, and 29 of treatment were assayed for mutagenicity using the Salmonella mutation assay. Most samples elicited a significant positive response on Salmonella strains TA98, YG1041, and YG1042 with and without S9 metabolic activation; however, TA100 failed to detect mutagenicity in any sample. Changes in the mutagenic activity of the fractions across treatment time and metabolic activation conditions suggests a pattern of formation and transformation of mutagenic compounds that may include a wide range of PAH derivatives such as aromatic amines, oxygenated PAHs, and S‐heterocyclic compounds. The prior chemical analyses documented the formation of oxygenated PAHs during the treatment (e.g., 4‐oxapyrene‐5‐one), and the mutagenicity analyses showed high corresponding activity in the semipolar fraction with and without metabolic activation. However, it could not be verified that these specific compounds were the underlying cause of the observed changes in mutagenic activity. The results highlight the need for concurrent chemical and toxicological profiling of contaminated sites undergoing remediation to ensure elimination of priority contaminants as well as a reduction in toxicological hazard. Moreover, the results imply that remediation efficacy and utility be evaluated using both chemical and toxicological metrics. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.     

Mutagenicity tests of fabric-finishing agents in salmonella typhimurium: Fiber-reactive wool dyes and cotton flame retardants

Thirty-nine fabric-finishing agents were tested for mutagenic activity in Salmonella typhimurium. Twenty-four fiber-reactive wool dyes and three acid dyes (not fiber-reactive) were screened by spot tests in strains TA100, TA98, TA1535, and TA1537. Among these dyes, seven bromoacrylamide dyes and one vinyl sulfone dye were mutagenic. Additionally, one of the three acid dyes was mutagenic in spot tests. The mutagenicity of the acid dye was due to an impurity or breakdown product rather than to the dye itself; the origin of the activities of the other dyes is unknown. No mutagenicity was observed among five chlorotriazine or four sulfonyl-ethane sulfonic acid dyes. Eight phosphorus-containing flame retardants (phosphonium, phosphine, phosphine oxide, and phosphonic acid derivatives) and methyl-N-methylolcarbamate, which is employed to obtain a flame-retardant finish on cotton, were tested for mutagenicity in strains TA100, TA98, TA1535, and TA1537, using quantitative incorporation assays. All were nonmutagenic. Two of three bromoalkyl-substituted triazine flame retardants were mutagenic in strains TA100 and TA1535. It is unknown whether this activity is due to impurities or to the parent compound. The flame retardants tested were either in actual commercial use or in experimental development for potential commercial processes. These results indicate the need for early testing of potential fabric-finishing agents and processes.     

Structure–activity investigation of the potentiating effect of cyano substitution on nitroaniline mutagenicity in the ames test

2,6‐Dicyano‐4‐nitroaniline and 2‐cyano‐4‐nitroaniline (CNNA; 2‐amino‐5‐nitrobenzonitrile) are potent mutagens in the Ames test, even though unsubstituted nitroanilines (NAs) are no more than weak mutagens. These compounds are putative reduction products of many commercial azo dyes, including Disperse Blue 165, Disperse Blue 337, Disperse Red 73, Disperse Red 82, Disperse Violet 33, and Disperse Violet 63. We have examined the mutagenicity in strains TA98 and YG1024 of a series of commercially‐available isomers of CNNA, and some related compounds, to probe the relationship between structure and genotoxic activity in this class of compounds. The potentiating effect of the cyano substituent is seen in many cases; e.g. 2‐amino‐4‐nitrobenzonitrile is a much more potent mutagen than 3‐NA. 2,4‐Dinitrobenzonitrile is also highly mutagenic. Possible mechanisms for the “cyano effect” are considered, with respect to the likely structures of cyanonitroaniline‐DNA adducts and the roles of the enzymes (nitroreductase and acetyl CoA:arylamine N‐acetyltransferase) believed to be involved in the activation of nitroaromatic compounds. Environ. Mol. Mutagen. 59:114–122, 2018. © 2017 Wiley Periodicals, Inc.     

Evaluation of the mutagenicity of nitration products derived from phenalenone (1H-phenalen-1-one)

1H-Phenalen-1-one (phenalenone) is one of the major oxygenated polyaromatic compounds present in the atmospheric environment. In order to gain detailed information regarding the mutagenicity and physicochemical properties of the nitration products of phenalenone, we measured Ames Salmonella mutagenicity, lower LUMO (lowest unoccupied molecular orbital) energy and octanol-water partition coefficient of the products obtained from the nitration reaction of phenalenone. Both nitration reactions of phenalenone, i.e. with mixed inorganic acids (a mixture of nitric acid and sulphuric acid) and with NO(2)-O(3) in an aprotic solvent, preferentially afforded the nitration products 2-nitrophenalenone and 5-nitrophenalenone. Formation of a 6-nitro derivative of phenalenone was, however, only observed in the nitration reaction with sulphuric acid. Moreover, dinitro derivatives of phenalenone and also two oxidatively decomposed products of nitrophenalenone, i.e. 3-nitro- and 4-nitronaphthalic anhydride, were isolated from the reaction mixture. The mutagenicities of the six nitro compounds obtained from the nitration reactions were tested with the Salmonella strains TA98, TA100, YG1021 and YG1024 in the absence of S9 mix. Among these products, 2-nitrophenalenone exhibited the most potent mutagenic activity against TA98, TA100 and YG1024 (160, 230 and 2800 revertants/nmol for strains TA100, TA98 and YG1024, respectively), whereas 2,5-dinitrophenalenone exerted the highest mutagenicity against YG1021. Semi-empirical calculation showed that among the mononitrophenalenone series, the mononitro derivatives possessing lower LUMO energy tended to exhibit greater mutagenic activity than those with higher LUMO energy. This tendency, however, did not extend to the compounds with different aromatic ring systems due to the considerable differences in the hydrophobicities of these compounds.     

Comparison of genotoxicity of textile dyestuffs in Salmonella mutagenicity assay, in vitro micronucleus assay, and single cell gel/comet assay.

The mutagenicity of textile dyes is an important consideration for the assurance of consumer protection and work safety. The mutagenicity testing of textile dyestuffs is crucial for accurately predicting health risks for consumers and workers exposed to dyes. Unfortunately, these data are often lacking. We studied the genotoxic activity of ten selected commercial textile dyestuffs, which are made up of mixtures of azo dyes and azo metal complex dyes as well as two anthraquinone dyestuffs. We used the Salmonella mutagenicity assay and cultured human keratinocytes (HaCaT cell line). In the S. typhimurium strain TA98, with and without S9, eight often dyestuffs investigated, and in strain TA 100, with and without S9, six often dyes caused frameshift mutations and base-pair substitutions in the dose range of 1-5000 microg/plate in a dose-related manner. All dyes, including those negative in the Salmonella mutagenicity assay, induced clastogenic effects in the in vitro micronucleus (MN) test in HaCaT cells as direct-acting mutagens in the concentration range of 5-150 microg/mL and with maximum MN frequencies between 1.1 and 7.2%, compared to negative controls that showed 0.2-0.4% MN cells. In the single cell gel/comet assay, all ten dyestuffs investigated caused DNA damage in HaCaT keratinocytes. The alkaline (pH >13) version used is capable of detecting DNA single strand breaks, alkali-labile sites, and DNA-DNA/DNA-protein cross-linking. Under the conditions of these screening tests, the textile dyes investigated are direct-acting genotoxic substances. The HaCaT cells testing protocol proposed has been shown to be an appropriate test system for evaluating mutagenicity of textile dyes on a base level.     

Evaluation of the genotoxicity of river sediments from industrialized and unaffected areas using a battery of short-term bioassays

The present investigation evaluated the capacity of the Salmonella mutagenicity test, the comet assay, and the micronucleus assay to detect and characterize the genotoxic profile of river sediments. Three stations were selected on an urban river (Bouches du Rhône, France) exposed to various sources of industrial and urban pollution (StA, StB, and StC) and one station on its tributary (StD). One station in a nonurban river was included (REF). The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by HPLC, and the genotoxicity of the sediments was monitored by the Salmonella mutagenicity test (TA98 + S9, YG1041 ± S9), the comet assay, and the micronucleus assay on CHO cells. Chemical analysis showed that the total PAH concentrations ranged from 23 μg kg^?1 dw (REF) to 1285 μg kg^?1 dw (StD). All the sediments were mutagenic in the Salmonella mutagenicity test. The mutagenicity was probably induced by the presence of nitroarenes (StA, StB, StC, and StD) and aromatic amines (REF) as deduced from the mutagenicity profiles of strains YG1041 ± S9 and TA98 + S9. The comet assay revealed direct DNA lesions in REF, StA, and StB sediments and metabolization‐dependent DNA damage in StC and StD. The micronucleus assay showed an absence of clastogenicity for StA ± S9 and StC‐S9, and a significant clastogenicity ± S9 for the three other stations. The genotoxicity ranking determined by the comet assay + S9 matched the ranking of total and carcinogenic PAH concentrations, and this assay was found to be the most sensitive. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.     

In vitro genotoxicity of dyes present in colored smoke munitions

Genetic toxicology studies were conducted on organic dyes and mixtures used in colored smoke munitions. The dyes studied included Solvent Red 1; two different batches (Lot 1 and Lot 2) of Disperse Red 11; terephthalic acid; and a mixture of 25 parts Solvent Red 1, 5 parts Disperse Red 11, and 16 parts terephthalic acid. The dyes were evaluated for their ability to produce mutations in Salmonella bacterial strains and in Chinese hamster ovary (CHO) cells. The dyes were also tested in CHO cells to determine cytotoxicity and the induction of sister chromatid exchanges and chromosome aberration. None of the dyes were genotoxic in the standard Ames assay using bacterial strain TA1535 or TA100 with or without the addition of S-9 or in TA98 and TA1538 without S-9. With S-9, Disperse Red 11 (Lot 2) showed significant mutagenic activity in TA98 and TA1538 which increased as a function of S-9 concentration. However, the maximum level of mutagenic activity detected was low (3.8 revertants/micrograms). The azo dye Solvent Red 1 was also negative in a pre-incubation assay designed to reduce azo compounds to free amines. Solvent Red 1 was cytotoxic to mammalian cells, caused a significant increase in SCE, but was not mutagenic or clastogenic. Disperse Red 11 (Lot 1 and Lot 2) were not cytotoxic or clastogenic but produced an increase in cell cycle time and SCE frequency. Only Disperse Red 11 (Lot 2) increased mutations in the CHO/hypoxanthine-guanine phosphoribosyltransferase (HGPRT) assay. The mutagenic activity of the dye mixture was not significant, suggesting no synergistic interaction between the dyes. These studies demonstrated that none of the dyes was clastogenic and that a contaminant in Disperse Red 11 (Lot 2) may be responsible for the weak mutagenic activity in both mammalian and bacterial cell systems.     

Physical‐chemical and microbiological characterization,and mutagenic activity of airborne PM sampled in a biomass‐fueled electrical production facility

Biomass combustion is used in heating and electric power generation in many areas of the world. Airborne particulate matter (PM) is released when biomass is brought to a facility, stored, and combusted. Occupational exposure to airborne PM within biomass‐fueled facilities may lead to health problems. In March and August of 2006, airborne PM was collected from a biomass‐fueled facility located in Denmark. In addition, source‐specific PM was generated from straw and wood pellets using a rotating drum. The PM was analyzed for polycyclic aromatic hydrocarbons (PAHs), metals, microbial components, mutagenic activity, and ability to generate highly reactive oxygen species (hROS) in cell‐free aqueous suspensions. PM collected from the boiler room and the biomass storage hall had higher levels of mutagenic activity, PAHs and metals, and a higher hROS generating potential than the source specific PM. The mutagenic activity was generally more potent without S9 activation, and on the metabolically enhanced strain YG1041, relative to TA98. Significant correlations were found between mutagenicity on YG1041 (without S9) and PAH concentration and mutagenicity on YG1041 (with S9) and hROS generating ability. PM collected in March was more toxic than PM collected in August. Overall, airborne PM collected from the facility, especially that from the boiler room, were more toxic than PM generated from straw and wood chips. The results suggest that exposure to combustion PM in a biomass‐fueled facility, which likely includes PM from biomass combustion as well as internal combustion vehicles, may contribute to an elevated risk of adverse health effects. Environ. Mol. Mutagen., 2011. © 2010 Wiley‐Liss, Inc.     

9-Methoxytariacuripyrone, a naturally occurring nitro-aromatic compound with strong mutagenicity in Salmonella typhimurium

9-Methoxytariacuripyrone, a nitro-aromatic compound isolatedfrom Aristolochia brevipesshowed strong mutagenic activity instrain TA98, TA100 and some YG strains of Salmonella typhimuriumwithand without S9 mix. Incubation with cytosol resulted in a heavyincrease in mutagenicity. When incubated with microsomes theactivity was dramatically decreased. The results are discussedin view of the enzymes possibly involved in activation and detoxificationof the compound. The role of the basic structure on the mutagenicitymediated through the nitro group was also considered.