Evaluation of mutagenic potential of contaminated atmosphere at Ibirapuera Park, São Paulo - SP, Brazil, using the Tradescantia stamen-hair assay

Assessment of genotoxicity of air pollution in urban areas using an integrated model of passive biomonitoring

Atmospheric pollution is a major public health issue and has become increasingly critical for human health. Urban atmospheric pollution is typically assessed through physicochemical indicators aligned with environmental legislation parameters, providing data on air quality levels. While the effects of pollution on sensitive organisms serve as a warning for public health decision-makers, there remains a need to explore the interpretation of environmental data on pollutants. The use of species adapted to urban environments as sentinels enables continuous and integrated monitoring of environmental pollution implications on biological systems. In this study, we investigated the use of the plant species Tradescantia pallida as a biomonitor to evaluate the genotoxic effects of atmospheric pollution under diverse vehicular traffic conditions. T. pallida was strategically planted at the leading urban intersections in Uberlândia, Brazil. During COVID-19 pandemic lockdowns, we compared indicators such as physical, biological, and traffic data at different intersections in residential and commercial zones. The reduction in vehicular traffic highlighted the sensitivity of plant species to changes in air and soil pollutants. T. pallida showed bioaccumulation of heavy metals Cd and Cr in monitored areas with higher traffic levels. Additionally, we established a multiple linear regression model to estimate genotoxicity using the micronucleus test, with chromium concentration in the soil (X1) and particulate matter (PM) in the atmosphere (X2) identified as the primary independent variables. Our findings provide a comprehensive portrait of the impact of vehicular traffic changes on PM and offer valuable insights for refining parameters and models of Environmental Health Surveillance.

Effects of urban-induced mutations on ecology, evolution and health

Increasing evidence suggests that urbanization is associated with higher mutation rates, which can affect the health and evolution of organisms that inhabit cities. Elevated pollution levels in urban areas can induce DNA damage, leading to de novo mutations. Studies on mutations induced by urban pollution are most prevalent in humans and microorganisms, whereas studies of non-human eukaryotes are rare, even though increased mutation rates have the potential to affect organisms and their populations in contemporary time. Our Perspective explores how higher mutation rates in urban environments could impact the fitness, ecology and evolution of populations. Most mutations will be neutral or deleterious, and higher mutation rates associated with elevated pollution in urban populations can increase the risk of cancer in humans and potentially other species. We highlight the potential for urban-driven increased deleterious mutational loads in some organisms, which could lead to a decline in population growth of a wide diversity of organisms. Although beneficial mutations are expected to be rare, we argue that higher mutation rates in urban areas could influence adaptive evolution, especially in organisms with short generation times. Finally, we explore avenues for future research to better understand the effects of urban-induced mutations on the fitness, ecology and evolution of city-dwelling organisms.

Assessment of the mutagenic potential of the water of an urban river by means of two Tradescantia-based test systems

River pollution can be caused by anthropogenic or natural factors. When testing water quality for the presence of toxic substances, higher plants as bioindicators for the genotoxic effects of complex mixtures are effective and appropriate. Hence, in this work the Tradescantia (clone 02) stamen hair mutations (Trad-SHM) and Tradescantia micronuclei (Trad-MCN) were used to determine mutagenic and clastogenic potential of an urban river. A significant increase in the level of all studied endpoints as well as morphological changes, including pink cells (PC) and colorless cells (CC) in stamen hairs, stunted hairs (SH), tetrads with micronuclei (MN) and MN in tetrads of pollen microspores in the Tradescantia was observed compared to the negative control (tap water). As an example riverine system, part of the River Hrazdan (Armenia) flowing through a highly urbanized and industrial area was studied. The positive control (10 mM CrO₃) showed the highest genotoxicity for the SHM assay (PC: 5.1 / 1000, CC: 17.9 / 1000) and for the MCN assay (12 MN / 100 tetrads and 9.4 ± 0.53 tetrads with MN). Genetic responses were analyzed in conjunction with the concentrations of select elements in the riverine water. Reasons for observing such a high level of genetic markers in the riverine water and applicability of the Tradescantia (clone 02) test-systems in environmental risk assessment and biomonitoring are discussed.

Tradescantia as a biomonitor for genotoxicity evaluation of diesel and biodiesel exhaust emissions

Biodiesel, an alternative energy source, is promoted as cleaner and safer than other fuel options due to its reported reduction of particulate and gaseous emissions (CO₂, CO, and total hydrocarbons). However, its volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbon (PAHs) emissions are key to understanding its toxic, mutagenic and carcinogenic risk factors. This research was developed to assess the genotoxic impact of exhaust emissions using biodiesel from animal fat, palm oil and soybean oil blended with diesel (B80). Diluted exhaust gases were analyzed simultaneously for pollutant emissions and for toxicity using an exposure chamber called the BioToxMonitor, where Tradescantia pallida and a KU-20 clone were exposed to exhaust following Trad-MCN and Trad-SH bioassays. The results show differences in the emission compositions and considerable mutagenic potential among the three biodiesels tested, with palm oil biodiesel emissions being the least harmful, based on its low pollutant concentrations and the negative response in the TradSH bioassay. In contrast, the animal fat biodiesel and soybean oil biodiesel emissions were as toxic as the diesel emissions, being positive in both Trad bioassays. This could be related to the PAH and carbonyl concentrations found in the vehicular exhaust. The genotoxicity of diesel emissions was related to PM₁ and the concentrations of both gas and particle PAHs concentrations, which were two times higher compared to the highest concentrations observed for biodiesel. The data suggest that micronucleus assays in Tradescantia pallida are more sensitive for gaseous pollutant exposure. This is the first reported study of biodiesel exhaust biomonitoring in situ and under controlled conditions inside an exposure chamber.

Tradescantia as a biomonitor for pesticide genotoxicity evaluation of iprodione, carbaryl, dimethoate and 4,4'-DDE

There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays. Biomonitor exposures were performed by capillary absorption for each individual pesticide over a wide range of concentrations, from maximum residue limits (trace levels) up to the application dose in agricultural fields. In addition, the organochloride 4,4'-DDE was included but only in the concentration range from 0.01mgL^-1 to 1mgL^-1, mimicking residue concentrations since it is not a commercial product but, rather, the main breakdown product of the persistent organochloride pesticide 4,4-DDT, whose use was discontinued in Chile in the 1980s. The Trad-MCN bioassay revealed a significant increase in micronucleus frequency at the early tetrads of meiotic pollen mother cells of the biomonitor Tradescantia pallida var. purpurea, induced by 4,4'-DDE (for 1mgL^-1), dimethoate (for 40mgL^-1, 200mgL^-1, 400mg/L^-1) and carbaryl (for 889mgL^-1). Iprodione did not generate any significant change at the tested concentration. Meanwhile, the Trad-SH bioassay was carried out by analysis of the phenotype variations of the stamen hair cells of the Tradescantia clone KU-20 for the same pesticides and doses. This bioassay was not sufficiently sensitive for toxicity evaluation of most of the pesticides tested, with exception of dimethoate in low doses (2 and 5mg/L^-1).

Avaliação in situ da genotoxicidade de triazinas utilizando o bioensaio Trad-SHM de Tradescantia clone 4430

O bioensaio da mutação do pelo estaminal de Tradescantia clone 4430 (Trad-SHM) foi utilizado para avaliar a genotoxicidade de um herbicida composto por triazinas (atrazina e simazina) após exposição in situ. Trinta vasos da planta foram expostos durante a aplicação do herbicida (grupo teste) mantendo-se um grupo controle em casa de vegetação. A genotoxicidade foi expressa em termos de eventos mutantes pink (EMP) e a análise dos dados foi realizada por meio do teste t de Student em oito dias de avaliação (C8D = controle 8 dias; T8D = teste 8 dias) e no dia de pico (CPD = controle dia de pico; TPD = teste dia de pico). A exposição ao herbicida causou um número significativamente maior de EMP no grupo teste (T8D = 2,27; TPD = 4,69) do que no controle (C8D = 0,71; CPD = 0,62), demonstrando a existência de risco genotóxico associado ao uso das triazinas, sendo o bioensaio Trad-SHM uma eficiente ferramenta para avaliar o potencial genotóxico destes contaminantes ambientais causadores de efeitos adversos à saúde humana.

Metal embryotoxicity from urban particles in Sao Paulo city: an experimental study in chicken embryos

Chicken eggs were inoculated with suspensions of ambient air particles (<or=10 microm, PM10) from Sao Paulo city in 3, 0.3 or 0.03 microg doses on one of the four early days of embryo development. On the eleventh day of development alterations were observed on embryos inoculated with PM10 3 microg on the third day. Particles analysis showed high content of metals. Hence, embryos were also inoculated with PM10 (3 microg) combined with metal chelating EDTA. PM10 (3 microg) embryos presented underdevelopment (stage 29.44+/-11.4) compared to vehicle and positive controls (stage 36.44+/-0.51 Saline and stage 31.20+/-9.7 Cyclophosphamide, p<or=0.05); higher (47%) mortality rate (23% Saline and 42% Cyclophosphamide) and low (68%) viability (100% Saline and 70% Cyclophosphamide, p=0.04). Effects were attenuated when embryos received PM10+EDTA (stage 33.63+/-0.94, 18.9% mortality rate and 82% viability). PM10 from Sao Paulo city is embryotoxic and metal may be implicated in the toxic mechanism.

Biomonitoring genotoxic risks under the urban weather conditions and polluted atmosphere in Santo André, SP, Brazil, through Trad-MCN bioassay

The present study was made to check if the Trad-MCN bioassay, developed with inflorescences of Tradescantia pallida cv. Purpurea, might discriminate genotoxic risks in areas of the city of Santo André (SE Brazil) contaminated by different air pollutants, and periods of the year when risks are higher, and to determine if the variations in the frequency of micronuclei (MCN) can be explained by environmental factors that characterize the stressful situation in each site. Potted plants were exposed in sites highly contaminated by ozone (Capuava and School) and in sites reached by high vehicular emissions (downtown and Celso Daniel Park). Pedroso Park, far from the polluted areas, was taken as reference. From September 2003 to September 2004, 20 young inflorescences were collected twice a week from each place and the frequencies of MCN were estimated. The environmental conditions observed in the polluted sites were stressful enough to promote an increase of MCN, mainly in sites reached by high vehicular emissions. But MCN rates in Capuava and at Celso Daniel Park could not be predicted only by pollutants which characterized the air contamination in these sites. More severe weather conditions, mainly low temperature, relative humidity and rainfall, caused an increase of MCN. Improvement of the biomonitoring system is recommended to minimize this negative influence of weather factors.