Tradescantia Micronucleus Test Research Articles

Evaluation of vehicular pollution using the TRAD-MCN mutagenic bioassay with Tradescantia pallida (Commelinaceae)

Biomonitoring is one of the tools used to assess the mutagenic potential of the atmosphere. In this study, the mutagenicity of Tradescantia pallida, a species of plant largely present in urban environments, was investigated. The objectives of this study was to estimate the mutagenic potential of vehicular flow through the TRAD-MCN bioassay in cities located at different altitudes in the southwest mesoregion of Mato Grosso do Sul, Brazil, to infer possible abiotic agents that may contribute to the effects of atmospheric pollutants, and finally to map the cities with greater risks to the health of the local population. To achieve these objectives, the Tradescantia-micronucleus test was performed on young buds of T. pallida collected between August 2015 and August 2016 in nine cities of Mato Grosso do Sul. These buds were exposed to traffic flows of various intensities. The data collected consisted of measurements of meteorological parameters and vehicular traffic counts for each city. The variables considered were: mean ambient temperature; micronuclei frequency; vehicular flow; altitude; relative humidity; pluviosity. The application of the Trad-MCN bioassay, with the consideration of environmental variables and altitudes, and the use of the Kernel interpolation technique, allowed us to map the areas with significant pollution risks to the population. The highest frequency of exposure to mutagens occurred in the cities with the highest vehicular traffic intensity. The average ambient temperature failed to show a linear association with the frequency of the micronuclei in the samples analyzed (r = 0.11ns). A positive correlation was observed between micronuclei frequency and vehicular flow, (r = 0.67; p ≤ 0.001%) and between micronuclei frequency and altitude (r = 0.24; p ≤ 0.05). A negative correlation was found between relative humidity and micronuclei frequency (r = −0.19; p ≤ 0.05%). Thus, higher micronuclei frequency tended to be present in locations with low relative humidity and high altitudes and vehicular flow.

The Tradescantia micronucleus assay is a highly sensitive tool for the detection of low levels of radioactivity in environmental samples

Environmental contamination with radioactive materials of geogenic and anthropogenic origin is a global problem. A variety of mutagenicity test procedures has been developed which enable the detection of DNA damage caused by ionizing radiation which plays a key role in the adverse effects caused by radioisotopes. In the present study, we investigated the usefulness of the Tradescantia micronucleus test (the most widely used plant based genotoxicity bioassay) for the detection of genetic damage caused by environmental samples and a human artifact (ceramic plate) which contained radioactive elements. We compared the results obtained with different exposure protocols and found that direct exposure of the inflorescences is more sensitive and that the number of micronuclei can be further increased under “wet” conditions. The lowest dose rate which caused a significant effect was 1.2 μGy/h (10 h). Comparisons with the results obtained with other systems (i.e. with mitotic cells of higher plants, molluscs, insects, fish and human lymphocytes) show that the Tradescantia MN assay is one to three orders of magnitude more sensitive as other models, which are currently available. Taken together, our findings indicate that this method is due to its high sensitivity a unique tool, which can be used for environmental biomonitoring in radiation polluted areas.

Biomonitoring air quality during and after a public transportation strike in the center of Uberlândia, Minas Gerais, Brazil by Tradescantia micronucleus bioassay

The aim of this study was to address the lack of information concerning the air quality in the city of Uberlândia, Minas Gerais, Brazil. In this study, we conducted an unprecedented experiment involving the in situ biomonitoring of air genotoxicity in the city center during and after a public transportation strike using the Tradescantia micronucleus test. The frequency of micronuclei was significantly higher in the city center compared with the reference site (Mann-Whitney test, p < 0.05), with the highest MN levels being observed during public transport stoppage (Kruskal-Wallis, Dunn p < 0.01). In addition, the multiple linear regression analyses revealed that the low circulation of buses during public transport stoppage and the increase in the concentration of particulate matter from the increased flow of vehicles in the city center during the strike positively influenced the MN frequency. The climatic factors did not change during the biomonitoring period, reflecting the fact that climatic factors did not influence the MN frequency.

Genotoxic and phytotoxic risk assessment of fresh and treated hydrochar from hydrothermal carbonization compared to biochar from pyrolysis

Biochar is discussed as an option for climate change mitigation via C sequestration and may promote sustainable resource efficiency. Large-scale field trials and commercial business with char materials have already started. Therefore char materials have to be assessed for toxic compounds. We tested genotoxic effects of different hydrochars and biochars with the Tradescantia micronucleus test. For this purpose chromosomal aberrations in pollen cells of Tradescantia in the form of micronuclei were evaluated microscopically after defined exposition to extracts from char materials. Hydrochars from hydrothermal carbonization mostly exhibited significantly negative results. Additional germination experiments with hydrochar showed total germination inhibition at additions above five percent v/v in comparison to biochar. However, biological post-treatment of previously toxic hydrochar was successful and toxic effects were eliminated completely. Some post-treated hydrochars even showed growth stimulating effects. Our results clearly demonstrate the necessity of risk assessment with bioindicators. The chosen tests procedures can contribute to biochar and hydrochar characterization for safe application.

Chemopreventive activity of compounds extracted from Casearia sylvestris (Salicaceae) Sw against DNA damage induced by particulate matter emitted by sugarcane burning near Araraquara, Brazil

Ethanolic extract of Casearia sylvestris is thought to be antimutagenic. In this study, we attempted to determine whether this extract and casearin X (a clerodane diterpene from C. sylvestris) are protective against the harmful effects of airborne pollutants from sugarcane burning. To that end, we used the Tradescantia micronucleus test in meiotic pollen cells of Tradescantia pallida, the micronucleus test in mouse bone marrow cells, and the comet assay in mouse blood cells. The mutagenic compound was total suspended particulate (TSP) from air. For the Tradescantia micronucleus test, T. pallida cuttings were treated with the extract at 0.13, 0.25, or 0.50mg/ml. Subsequently, TSP was added at 0.3mg/ml, and tetrads from the inflorescences were examined for micronuclei. For the micronucleus test in mouse bone marrow cells and the comet assay in mouse blood cells, Balb/c mice were treated for 15days with the extract—3.9, 7.5, or 15.0mg/kg body weight (BW)—or with casearin X—0.3, 0.25, or 1.2mg/kg BW—after which they received TSP (3.75mg/kg BW). In T. pallida and mouse bone marrow cells, the extract was antimutagenic at all concentrations tested. In mouse blood cells, the extract was antigenotoxic at all concentrations, whereas casearin X was not antimutagenic but was antigenotoxic at all concentrations. We conclude that C. sylvestris ethanolic extract and casearin X protect DNA from damage induced by airborne pollutants from sugarcane burning.

Micronucleus study of the quality and mutagenicity of surface water from a semi-arid region

The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.

Micronúcleos em tétrades de &lt;em&gt;Tradescantia pallida&lt;/em&gt; (Rose) Hunt. cv. &lt;em&gt;purpúrea&lt;/em&gt; Boom: alterações genéticas decorrentes de poluição aérea urbana

The urban atmosphere contains a mixture of air pollutants, including mutagenic and carcinogenic substances. Associations between urban pollutants and respiratory/cardiovascular diseases and a greater incidence of certain cancer types have already been established in literature. Thus, biomonitoring procedures are required to evaluate the genotoxic potential of urban atmospheres. The Tradescantia micronucleus (Trad-MCN) test is one of the most commonly used bioassays for the detection of genotoxic effects. It is based on the formation of micronuclei resulting from chromosome breakage in the meiotic pollen mother cells of Tradescantia ssp. inflorescences. This study dealt with Trad-MCN for assessing the genotoxic potential of air in two areas of the municipality of Senhor do Bonfim/BA: (1) Lomanto Junior Highway (RLJ), an area of intense vehicular traffic; and (2) Nova do Congresso Plaza (PNC), an area with lower flow of vehicles. The negative control (CTR) was installed in Campus VII of the State University of Bahia. Plants exposed in RLJ and PNC presented the highest frequency of micronuclei (MCN), in comparison with CTR plants (p < 0.05). The increase in the frequency of observed MCN points to the efficiency of the Trad-MCN and indicates the potential mutagenic risk of substances present in atmospheric air.

In situ monitoring of the genotoxic effects in the vicinity of a petrochemical plant with the Tradescantia micronucleus (Trad-MCN) and with pollen abortion test

The aim of this study was to monitor the genotoxic effects of polluted air in Bratislava (Slovakia). In situ monitoring was carried out at a location polluted with emissions from a city incinerator and of a petrochemical plant. The Tradescantia micronucleus (Trad-MCN) test and pollen abortion assays with wild life plants (Chelidonium majus, Clematis vitalba, Cichorium intybus, Linaria vulgaris) were used in this study. The experiments were carried out during two sampling periods i.e. 1997–2000 and 2003–2006. Compared to the effects seen in Tradescantia plants exposed in a rural area with low pollution levels, the MCN frequencies in pollen tetrads were significantly higher in specimens from the urban site during the first period whereas no significant differences were found during the second sampling period. The results of the pollen abortion assays showed a similar pattern as that observed in the TradMCN bioassays, i.e. pronounced effects were only seen between 1997 and 2000. The differences of the results obtained in the two sampling periods can be explained by reduction of the pollution of the urban air due to new production technologies and installation of filter systems which led to a substantial improvement of air quality parameters such as particulate matter, organic volatiles and SO2 emissions. These results confirm the sensitivity of the Tradescantia MCN test and of pollen abortion assays for the detection of air pollution and that both biomonitoring models reflect improvement of air quality parameters. from 13th Scientific Symposium of the Austrian Pharmacological Society (APHAR). Joint Meeting with the Austrian Society of Toxicology (ASTOX) and the Hungarian Society for Experimental and Clinical Pharmacology (MFT) Vienna, Austria. 22–24 November 2007

Genotoxicity evaluation of water soil leachates by Ames test, comet assay, and preliminary Tradescantia micronucleus assay

Combining genotoxicity/mutagenicity tests and physico-chemical methodologies can be useful for determining the potential genotoxic contaminants in soil samples. The aim of our study was to evaluate the genotoxicity of soil by applying an integrated physico-chemical-biological approach. Soil samples were collected at six sampling points in a Slovenian industrial and agricultural region where contamination by heavy metals and sulphur dioxide (SO(2)) are primarily caused by a nearby power plant. The in vitro alkaline version of the comet assay on water soil leachates was performed with Caco-2 and HepG2 cells. A parallel genotoxicity evaluation of the samples was performed by Ames test using Salmonella typhimurium and the Tradescantia micronucleus test. Pedological analyses, heavy metal content determination, and different physico-chemical analyses, were also performed utilizing standard methodology. Water leachates of soil samples were prepared according to standard methods. Since only a battery of biotests with prokaryotic and eukaryotic organisms or cells can accurately estimate the effects of (geno)toxicants in soil samples and water soil leachates, a combination of three bioassays, with cells or organisms belonging to different trophic levels, was used. Genotoxicity of all six water soil leachates was proven by the comet assay on both human cell lines, however no positive results were detected by bacterial assay, Ames test. The Tradescantia micronucleus assay showed increase in micronuclei formation for three samples. According to these results we can assume that the comet assay was the most sensitive assay, followed by the micronucleus test. The Ames test does not appear to be sensitive enough for water soil leachates genotoxicity evaluations where heavy metal contamination is anticipated.

In situ monitoring of clastogenicity of ambient air in Bratislava, Slovakia using the Tradescantia micronucleus assay and pollen abortion assays

Aim of this study was to monitor the genotoxic effects of polluted air in Bratislava (Slovakia) with the Tradescantia micronucleus (Trad-MN) test. In situ monitoring was carried out at five locations during two seasons (years 2003 and 2004). Flower pots with Tradescantia paludosa (clone 03) plants were exposed for 6–8 weeks at the different sites each year. The highest MN levels were observed in the vicinity of an agrochemical factory (3.1 times higher than background level in 2003 and 2.7 times higher in 2004). Lower effects were seen when plants were exposed to urban traffic emissions or in the vicinity of a glass-producing plant (the MN frequencies ranged between 2.8 and 4.4 per 100 tetrads, respectively, while the control frequencies were 2.1–2.6 per 100 tetrads); exposure near a petrochemical plant had no significant effects. In pollen abortion assays, three wild growing species were used, namely, chicory ( Cichorium intybus L.), old man's beard ( Clematis vitalba L.) and common toadflax ( Linaria vulgaris Mill.). Again, the strongest effects were observed close to the agrochemical industry (reduction of fertile pollen by 5.6%, 11.1% and 8.3% in chicory, old mans beard and in toadflax, respectively). Cichorium intybus was the most sensitive species and the number of abortive pollen grains was 5.1 times higher in specimens collected near the agrochemical factory than that seen at the control location. These observations indicate that contaminated urban air has an impact on the fertility of wild plants. Furthermore, it is interesting that the same rank order of effects was seen in pollen abortion assays as in the Trad-MN test (agrochemical industry > technical glass industry ≥ traffic > city incinerator/petrochemical plant). These results confirm the sensitivity of the Tradescantia MN test and pollen abortion assays for the detection of air pollution, and show that distinct differences exist in genotoxicity of different sources of pollutants.

Tradescantia micronucleus test indicates genotoxic potential of traffic emissions in European cities

Urban atmospheres contain complex mixtures of air pollutants including mutagenic and carcinogenic substances such as benzene, diesel soot, heavy metals and polycyclic aromatic hydrocarbons. In the frame of a European network for the assessment of air quality by the use of bioindicator plants, the Tradescantia micronucleus (Trad-MCN) test was applied to examine the genotoxicity of urban air pollution. Cuttings of Tradescantia clone #4430 were exposed to ambient air at 65 monitoring sites in 10 conurbations employing a standardised methodology. The tests revealed an elevated genotoxic potential mainly at those urban sites which were exposed to severe car traffic emissions. This bioassay proved to be a suitable tool to detect local ‘hot spots’ of mutagenic air pollution in urban areas. For its use in routine monitoring programmes, however, further standardisation of cultivation and exposure techniques is recommended in order to reduce the variability of results due to varying environmental conditions.

Genotoxicity of drinking water disinfectants in plant bioassays

The genotoxicity of two widely used drinking water disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA, CH(3)-CO-COOH), was evaluated in three short-term plant tests: (1) induction of anaphase chromosome aberrations in the root cells of Allium cepa, (2) micronucleus induction in the root cells of Vicia faba, and (3) micronucleus induction in Tradescantia pollen cells. The study was carried out in the laboratory by directly exposing the plants to several concentrations of the disinfectants in redistilled water at unadjusted (acid) and adjusted (neutral) pHs. Both 0.1 and 0.2 mg/l NaClO induced chromosome aberrations in the Allium cepa test at acid pH, but concentrations up to 0.5 mg/l of all the disinfectants were negative at neutral pH. Concentrations ranging from 0.1 to 0.5 mg/l NaClO, ClO(2,) and PAA induced micronuclei in Vicia faba at acid pH, while 1-2 mg/l NaClO and ClO(2) and 0.5-2 mg/l PAA gave positive responses at neutral pH. Most of concentrations of ClO(2) produced positive responses in the Tradescantia micronucleus test. In general, the highest levels of genotoxicity were observed under acid conditions; at acid pH, significant effects were induced by low concentrations of ClO(2) and PAA. Since the test concentrations of disinfectants are typical of those encountered in the biocidal treatment of tap water and similar concentrations are consumed daily by a large number of people, the genotoxicity of these compounds may constitute a significant public health concern.

Assessment of the genotoxicity of 137Cs radiation using Vicia-micronucleus, Tradescantia-micronucleus and Tradescantia-stamen-hair mutation bioassays

Since the middle of the 20th century, ionizing radiations from radioactive isotopes including 137Cs have been investigated to determine their genotoxic impact on living organisms. The present study was designed to compare the effectiveness of three plant bioassays to assess DNA damage induced by low doses of 137Cs: Vicia-micronucleus test (Vicia-MCN), Tradescantia-micronucleus test (Trad-MCN) and Tradescantia-stamen-hair mutation test (Trad-SH) were used. Vicia faba (broad bean) and Tradescantia clone 4430 (spiderwort) were exposed to 137Cs according to different scenarios: external and internal (contamination) irradiations. Experiments were conducted with various levels of radioactivity in solution or in soil, using solid or liquid 137Cs sources. The three bioassays showed different sensitivities to the treatments. Trad-MCN appeared to be the most sensitive test (significative response from 1.5 kBq/200 ml after 30 h of contamination). Moreover, at comparable doses, internal irradiations led to larger effects for the three bioassays. These bioassays are effective tests for assessing the genotoxic effects of radioactive 137Cs pollution.

Pollen mother cells of Tradescantia clone 4430 and Tradescantia pallida var. purpurea are equally sensitive to the clastogenic effects of X-rays.

The Tradescantia micronucleus test is a sensitive bioassay for mutagenesis that may be employed both under field and laboratory conditions. This test has been standardized mostly on the basis of the results obtained with clone 4430. However, this clone is not well adapted to tropical weather, frequently showing problems with growth and flowering. In addition, it is attacked by parasites and insects, a fact that limits its use in field studies aiming at the biomonitoring of air pollution. In the city of São Paulo, Tradescantia pallida (Rose) Hunt. var. purpurea Boom is widely distributed as an ornamental plant in gardens and along roadsides and streets, mostly because of its natural resistance and its easy propagation. In this report, we present dose-response curves indicating that the sensitivity of T. pallida and clone 4430 to X-radiation (1, 10, 25 and 50 cGy) is similar. The results confirm our previous suggestion that T. pallida represents a good alternative for in situ mutagenesis testing in tropical regions, especially biomonitoring studies in which the exposure conditions may not be fully controllable.

Final Report on the Safety Assessment of Biotin

Biotin is a water-soluble vitamin used as a hair-conditioning agent and a skin-conditioning agent in many cosmetic products at concentrations ranging from 0.0001% to 0.6%. Although Biotin does absorb some ultraviolet (UV) radiation, the absorption shows no peaks in the UVA or UVB region. Biotin is rapidly metabolized and excreted in urine. Little acute oral toxicity is seen in animal tests. Short-term and subchronic toxicity studies likewise found no evidence of toxicity. Although intradermal injection of a small quantity of Biotin (0.1 ml) into guinea pig skin did not produce skin irritation, Biotin (0.1% at pH 7.3) did produce slight, transient ocular irritation in rabbit eyes. Biotin was not mutagenic in bacterial tests, but positive results were found in a Tradescantia micronucleus test. There was evidence of an increase in the number of resorptions in rats receiving Biotin by subcutaneous injection, with concomitant decreases in fetal, uterine, and placental weights. Another study of mice receiving Biotin orally or by subcutaneous injection found no differences between control and treatment groups. Although there is one case study reporting an urticarial reaction in the literature, there are a very large number of individuals exposed to Biotin on a daily basis, and there is not a parallel appearance of irritation, sensitization, or other adverse reactions. Based on these available data, it was concluded that Biotin is safe as used in cosmetic formulations.

Effect of five dietary antimutagens on the genotoxicity of six mutagens in the microscreen prophage‐induction assay

Dietary antimutagens have been studied extensively in the last two decades, using mainly bacterial and mammalian cells. These studies have shown that certain dietary antimutagens, acting individually or as mixtures, are useful in counteracting the effects of certain mutagens and/or carcinogens to which humans are commonly exposed. However, there are some inconsistencies among publications using different bioassays. The general purpose of the research presented here was to conduct a comparative study of the antigenotoxic activity of five dietary antimutagens against six mutagens, using three rather different short-term tests: the Microscreen prophage-induction assay, the Tradescantia micronucleus test, and the Salmonella/mammalian microsome test. In this study I report the results with the Microscreen prophage-induction assay. The antimutagens selected were chlorophyllin, β-carotene, and vitamins A, C, and E. The mutagens selected were 2-aminoanthracene, benzo[a]pyrene, 2-nitrofluorene, toxaphene, dichlorvos, and nitrofen. The results show that chlorophyllin and β-carotene inhibited the genotoxicity of all six mutagens; vitamin E inhibited all except dichlorvos; and vitamins C and A inhibited 2-aminoanthracene, benzo[a]pyrene, 2-nitrofluorene, and nitrofen. Environ. Mol. Mutagen. 36:206–220, 2000 © 2000 Wiley-Liss, Inc.

Effect of five dietary antimutagens on the genotoxicity of six mutagens in the microscreen prophage-induction assay

Dietary antimutagens have been studied extensively in the last two decades, using mainly bacterial and mammalian cells. These studies have shown that certain dietary antimutagens, acting individually or as mixtures, are useful in counteracting the effects of certain mutagens and/or carcinogens to which humans are commonly exposed. However, there are some inconsistencies among publications using different bioassays. The general purpose of the research presented here was to conduct a comparative study of the antigenotoxic activity of five dietary antimutagens against six mutagens, using three rather different short-term tests: the Microscreen prophage-induction assay, the Tradescantia micronucleus test, and the Salmonella/mammalian microsome test. In this study I report the results with the Microscreen prophage-induction assay. The antimutagens selected were chlorophyllin, beta-carotene, and vitamins A, C, and E. The mutagens selected were 2-aminoanthracene, benzo[a]pyrene, 2-nitrofluorene, toxaphene, dichlorvos, and nitrofen. The results show that chlorophyllin and beta-carotene inhibited the genotoxicity of all six mutagens; vitamin E inhibited all except dichlorvos; and vitamins C and A inhibited 2-aminoanthracene, benzo[a]pyrene, 2-nitrofluorene, and nitrofen.

The Tradescantia-micronucleus test on the genotoxicity of UV-B radiation

Lanzhou city is located in north central China near inner Mongolia. The solar UV-B background radiation in this area is occasionally extremely high (8 μW/cm 2). Such high background solar UV-B radiation could be attributed to the sporadic depletion of the ozone layer in the stratosphere. The excessive UV-B radiation is a potential hazard in the environment. This prompted the present study on the effect of UV-B radiation on the cytogenetic damage to pollen mother cells of the plant Tradescantia. The Tradescantia-micronucleus (Trad-MCN) test was used to determine the genotoxicity of UV-B radiation. In addition to the usual 10 h of solar emission of UV light a series of increasing dosages (2, 4, 6, 8 h) of artificial UV-B radiation was applied to Tradescantia (clone 3) plant cuttings. Inflorescences of the treated and control plants were fixed and used for preparation of microslides. Micronuclei frequencies were observed in the early tetrads to show the degree of genotoxicity. Results of two repeated experiments show a dose-related increase of MCN frequencies under normal sunshine days. In the third experiment conducted under a cloudy and rainy day and an extraordinary high solar UV-B background, the MCN frequencies were markedly higher than that of the negative control but did not show the clear dose response to the treatment as in the first two experiments. The Trad-MCN test has successfully detected the effect of artificial UV-B radiation over the solar UV-B background radiation.

Tradescantia-micronucleus assay on the water quality of lake Hongzhe in Jiangsu Province, China

Lake Hongzhe, located in the northwest part of the Province of Jiangsu, is one of the five largest freshwater lakes in China. It has great economic importance for the fishery industry and for scenic beauty. Effluents from the industrial development and runoff from farm chemicals have contributed increasingly to the water pollutants in recent years. For many years, water quality has been monitored only by chemical analysis. No information is provided from the chemical analysis on the toxicity level of the aquatic forms in the lake and the ecosystems that directly or indirectly depend upon this water. In the present study, some chemical components were determined from water samples collected from the lake and in addition, the genotoxicity of the same water samples was determined using the Tradescantia-micronucleus bioassay. Results confirmed that the quantity of pollutants in the water bears some relationship with the genotoxicity in terms of chromosome damage. High nitrates and nitrogen content were the main contributing factors observed. The use of bioassays such as the Tradescantia-micronucleus test together with chemical analyses to monitor the water quality is highly recommended for the general practice for the environmental monitoring stations through the country.

Monitoring of mutagens in urban air samples

This research was designed to examine the presence of mutagenic/carcinogenic compounds in urban airborne particulates sampled with the inhalable PM-10 high volume sampler in two different streets of Brescia, a heavily industrialized town in northern Italy, using the Tradescantia/micronucleus test and a bacterial mutagenicity test (Kado test, a more sensitive version of the Ames test). In addition, the Tradescantia/micronucleus test was used for in situ monitoring of gaseous pollutants in other urban areas of Brescia and in two car tunnels, one with heavy car traffic in Perugia, a town in central Italy, and one in Brescia with moderate traffic. The Tradescantia-micronucleus test carried out on extracts of airborne particulates gave positive results only for the sample collected in the traffic-congested street where also higher bacterial mutagenicity was found. The in situ monitoring of the urban areas with the Tradescantia/micronucleus test always gave negative results. Monitoring carried out in the two car tunnels showed a significant increase in micronuclei frequency only in flowers exposed in the smaller and more polluted tunnel.