Toxic effects of environmental pollutants: Comparative investigation using Allium cepa L. and Lactuca sativa L

Synthesis and evaluation of esters obtained from phenols and phenoxyacetic acid with significant phytotoxic and cytogenotoxic activities

There is a growing demand for herbicides that are more effective than conventional ones yet less harmful to ecosystems. In light of this, this study aimed to synthesize esters from phenols and phenoxyacetic acid, using compounds with known phytotoxic potential as starting materials. Phenoxyacetic acid was first synthesized and then utilized in the synthesis of seven esters through Steglich esterification, employing N,N'-dicyclohexylcarboimide and N,N-dimethylpyridin-4-amine in the presence of phenols (thymol, vanillin, eugenol, carvacrol, guaiacol, p-cresol, and β-naphthol), yielding esters 1-7. All synthesized compounds were characterized using mass spectrometry, 1H, and 13C NMR. These compounds were tested for phytotoxicity to evaluate their effects on the germination and root development of Sorghum bicolor and Lactuca sativa seeds, and for the induction of alterations in the mitotic cycle of meristematic cells of L. sativa roots. Esters 1, 3, 4, and 5 exhibited the most significant phytotoxic activity in both L. sativa and S. bicolor. Alterations in the mitotic index and frequency of chromosomal alterations in L. sativa roots revealed the cytotoxic, genotoxic effects, and the aneugenic mode of action of the tested molecules. These findings suggest that these compounds could serve as inspiration for the synthesis of new semi-synthetic herbicides.

Toxicity of paclobutrazol-based pesticide on Lactuca sativa L.: germination, seedling development, and DNA damage

Paclobutrazol, a fungicide of the triazole class, is widely used as an inducer of early flowering and fruiting by inhibiting gibberellin formation. However, biological assays using model organisms to evaluate their cytogenotoxic and mutagenic potential are still scarce. Therefore, this study aimed to investigate the effects of the commercial product Cultar® 250 SC (CP) and the pure substance (PBZ) on the germination and initial seedling development of Lactuca sativa L. (lettuce), in addition to evaluating the effects of CP on the mitotic activity and DNA, as we believe that PBZ has a greater toxic potential than CP on seed germination, and that the latter has cytogenotoxic and mutagenic effects on L. sativa. Lettuce seeds treated with CP and with PBZ in the doses of 0.25, 0.50, 1, 1.5, and 2 g L-1 showed significant reductions in germination rate, as well the CP reduced the root and initial development seedling development. PBZ showed greater inhibition of germination compared to CP. In direct exposure to PBZ, there was not sufficient seedling development for analysis, while in discontinuous treatment, there was inhibition of root growth (except for doses of 0.25 and 0.50 g L-1) and in the development of the aerial part. While no mitodepressive effect was observed in meristematic cells treated with CP, increased frequencies of chromosomal alterations, including condensed nuclei and micronuclei, were evident in both meristematic cells and the F1 region. The Comet assay further demonstrated higher levels of DNA damage at higher paclobutrazol doses, supporting the findings of increased micronucleus frequencies. Consequently, it can be concluded that the CP exhibits greater toxicity towards seed germination compared to lettuce seedlings, and PBZ has a greater toxic potential than CP in relation to these parameters. However, the impact of CP on seedlings was relatively minimal, as evidenced by their limited effects on development, cell proliferation, and DNA, suggesting a slight toxicity of this agent. Therefore, we infer that Cultar® 250 SC should be used with caution. Thus, this study emphasizes the importance of employing joint analyses to better elucidate and correlate the mechanisms of action of potentially toxic substances. Furthermore, it provides a basis for discussing the application of Cultar® 250 SC and seeking more sustainable alternatives in food production.

Eco(geno)toxicity of an acaricidal formulation containing chlorpyrifos, cypermethrin, and fenthion on different plant models and Artemia salina L

The mixture of pesticides is widely employed in cattle farming to combat ectoparasite resistance, such as ticks. The commercial formulation COLOSSO FC30, which contains three active ingredients (Cypermethrin, Chlorpyrifos, and Fenthion), stands out due to its efficiency. However, animals exposed to this product may become vectors of potentially toxic molecules, possibly causing contamination in aquatic and terrestrial ecosystems. In light of this, this study evaluated the eco(geno)toxic potential of the commercial formulation COLOSSO FC30, using plants (Allium cepa L., Lactuca sativa L., Raphanus sativus L., Pennisetum glaucum L., and Triticum aestivum L.) and Artemia salina L. as model organisms. In the phytotoxicity test, the species were ranked in order of sensitivity to the commercial formulation as follows: P. glaucum > L. sativa > T. aestivum > R. sativus. The most sensitive parameters were root length (RL) and shoot length (SL) of seedlings. In the cytogenotoxicity test with A. cepa, cell division was decreased at concentrations from 0.351 mL L-1 in the meristematic region and root F1. Chromosomal aberrations and micronucleus were observed at all concentrations. In the test with A. salina, the IC50 after 24 h of exposure was 0.01207 mL L-1 of the commercial formulation. The results highlight the need for further research and regulations to understand and minimize the potential environmental impacts of COLOSSO FC30.

Effects of a S-metolachlor based herbicide on two plant models: Zea mays L. and Lactuca sativa L

Corn is the second most cultivated crop in Brazil, the number-one country in pesticide consumption. Chemical control of weeds is performed using herbicides such as S-metolachlor with pre- and post-emergence action and thus the toxicity of herbicides constitutes a matter of great concern. The present investigation aimed to examine the effects of an S-metolachlor-based herbicide on Lactuca sativa L. (lettuce) and Zea mays L. (maize) utilizing various bioassays. The test solutions were prepared from commercial products containing the active ingredient. Seeds from the plant models were exposed in petri dishes and maintained under biochemical oxygen demand (BOD) at 24°C. Distilled water was negative and aluminium positive control. Macroscopic analyses (germination and growth) were conducted for both plant species, and microscopic analysis (cell cycle and chromosomal alterations) were performed for L. sativa root tip cells. Detrimental interference of S-metolachlor-based herbicide was noted with lettuce for all parameters tested reducing plant germination by over 50% and the germination speed by over 45% and showing a significant decrease in mitotic index, from 16.25% to 9,28% even on the lowest concentration tested. In maize, there was no significant interference in plant germination; however, speed of germination was significantly hampered, reaching a 51.22% reduction for the highest concentration tested. Data demonstrated that the herbicide was toxic as evidenced by its phyto- and cytotoxicity in L. sativa L. and Z. mays L.

Investigation of the protective role of Ginkgo biloba L. against phytotoxicity, genotoxicity and oxidative damage induced by Trifloxystrobin

Trifloxystrobin (TFS) is a widely used strobilurin class fungicide. Ginkgo biloba L. has gained popularity due to its recognized medicinal and antioxidant properties. The aim of this study was to determine whether Ginkgo biloba L. extract (Gbex) has a protective role against TFS-induced phytotoxicity, genotoxicity and oxidative damage in A. cepa. Different groups were formed from Allium cepa L. bulbs subjected to tap water (control), 200 mg/L Gbex (Gbex1), 400 mg/L Gbex (Gbex2), 0.8 g/L TFS solution (TFS), 200 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex1) and 400 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex2), respectively. The phenolic composition of Gbex and alterations in the morphological, physiological, biochemical, genotoxicity and anatomical parameters were evaluated. Rutin, protocatechuic acid, catechin, gallic acid, taxifolin, p-coumaric acid, caffeic acid, epicatechin, syringic acid and quercetin were the most prevalent phenolic substances in Gbex. Rooting percentage, root elongation, weight gain, chlorophyll a and chlorophyll b decreased by approximately 50%, 85%, 77%, 55% and 70%, respectively, as a result of TFS treatment compared to the control. In the TFS group, the mitotic index fell by 28% compared to the control group, but chromosomal abnormalities, micronuclei frequency and tail DNA percentage increased. Fragment, vagrant chromosome, sticky chromosome, uneven chromatin distribution, bridge, vacuole-containing nucleus, reverse polarization and irregular mitosis were the chromosomal abnormalities observed in the TFS group. The levels of proline (2.17-fold) and malondialdehyde (2.71-fold), as well as the activities of catalase (2.75-fold) and superoxide dismutase (2.03-fold) were increased by TFS in comparison to the control. TFS-provoked meristematic disorders were damaged epidermis and cortex cells, flattened cell nucleus and thickened cortex cell wall. Gbex combined with TFS relieved all these TFS-induced stress signs in a dose-dependent manner. This investigation showed that Gbex can play protective role in A. cepa against the phytotoxicity, genotoxicity and oxidative damage caused by TFS. The results demonstrated that Gbex had this antioxidant and antigenotoxic potential owing to its high phenolic content.

Bioactivity of hydroalcoholic extracts from tropaeolum majus L. (tropaeolaceae) on the germination, initial plant development and cell cycle of Lactuca sativa L

Natural products are usually considered harmless; however, these substances need to be consumed with caution. Biological assays with plant models are a suitable alternative for prospective studies to assess natural product-initiated toxicity. The aim of this study was to examine the toxic potential of leaf and flower extracts derived from Tropaeolum majus L. a widely used plant in traditional medicine. Seeds of Lactuca sativa L. were exposed to T. majus extracts and based upon the seedling growth curve values, the 50% Inhibition Concentration (IC50) was calculated and applied for cell cycle analysis exposure. Both extracts contained organic acids, proteins, amino acids, and terpene steroids. Sesquiterpene lactones and depside were detected in leaf extracts. The higher concentration tested exhibited a marked phytotoxic effect. The extracts induced clastogenic, aneugenic cytotoxic, and potential mutagenic effects. The possible relationships between the classes of compounds found in the extracts and effects on cells and DNA were determined.

Toxicogenetic, biochemical, and physiological effects of azoxystrobin and carbendazim fungicides over Lactuca sativa L. and Phaseolus vulgaris L

Fungicides are pesticides that are frequently used in agriculture because of their action against fungal diseases. However, the widespread application of pesticides around the world raises environmental and public health concerns, since these compounds are toxic and can pose risks to ecosystems and human health. The aim of this study was to evaluate the phytotoxic, cytogenotoxic, and biochemical effects of azoxystrobin and carbendazim on Lactuca sativa L. and their physiological effects on Phaseolus vulgaris L. by analyzing the cell cycle and chromosomal and nuclear alterations in L. sativa; the biochemical effects of azoxystrobin and carbendazim on Phaseolus vulgaris L. and their physiological effects on Phaseolus vulgaris L. by analyzing the cell cycle and chromosomal and nuclear alterations in L. sativa; the biochemical effects by analyzing the activity of antioxidant enzymes in L. sativa; and the physiological effects by analyzing chlorophyll content and chlorophyll a fluorescence in P. vulgaris. It was observed that both fungicides were phytotoxic and cytotoxic, reducing root growth and the mitotic index, cytogenotoxic, increasing the occurrence of chromosomal alterations, as well as inducing oxidative stress and an increase in chlorophyll fluorescence emission and altered energy absorption in the plants used as a test system. In view of this, studies such as the one presented here indicate that the use of pesticides, even in small quantities, can lead to damage to the metabolism of plant organisms.

Is pearl millet (Pennisetum glaucum) a good plant species for ecotoxicological tests?

Various plant species can be selected for environmental testing, including pearl millet (Pennisetum glaucum (L.) R. Br), a globally significant cereal crop. This study aims to assess millet's suitability as a species for ecotoxicological tests, examining (1) germination and initial development dynamics, (2) the minimum seed quantity for reliable sampling, (3) optimal experimental design with replication numbers, (4) suitability of positive control, and (5) the effectiveness of the protocol in evaluating toxic effects of environmental pollutants. Millet exhibited rapid and uniform germination as well as consistent initial seedling development. To establish the minimum number of seeds required for reliable experimentation, germination, and seedling growth were compared across plots containing 10, 25, and 50 seeds. Consequently, 10 seeds per plot were chosen for subsequent experiments to reduce labor and costs while maintaining reliability. To validate the selected experimental design, and to establish a positive control for assays, aluminum was used as a toxic element at concentrations ranging from 10-2 to 10-6 M. While aluminum did not affect the final percentage of germinated seeds, it did exhibit an impact on the Germination Speed Index (GSI). Significant differences in root and aerial growth, and with fresh weight, were observed. The 10-3M concentration was chosen as the positive control as the 10-2 concentration showed extreme toxicity. To assess the applicability of the established protocol in determining the toxic effects of environmental pollutants, millet roots were exposed to the toxic agents atrazine, cadmium, methyl methane sulfonate (MMS), and Spent pot liner (SPL). Millet demonstrated sensitivity and efficiency in response to these tests. In conclusion, millet proves to be an effective species for the toxicological risk assessment of environmental pollutants.

A study on phytogenotoxicity induced by biogenic amines: cadaverine and putrescine

Among the compounds present in necro-leachate, a liquid released during the process of decomposition of the human body, are the biogenic amines cadaverine and putrescine. Although some studies on necro-leachate have indicated a potential ecotoxicological and public health risk associated with it, the research on this type of contamination is still rather limited. This study presents information about the phytotoxic and cytogenotoxic potential of cadaverine and putrescine, evaluated separately and within a mixture. Phytotoxicity was evaluated through a germination test, the initial growth of seedlings with Lactuca sativa, and cytogenotoxicity through chromosomal aberration and micronucleus tests with Allium cepa. The L. sativa results showed a phytotoxic effect for the evaluated amines, by reducing root (> 90%) and hypocotyl (> 80%) elongation. The co-exposure of cadaverine and putrescine potentiated cytogenotoxic activity by aneugenic action in the meristematic cells of A. cepa. From this result, it is possible to infer the eco-toxicogenic potential of cadaverine and putrescine. This study not only highlights the importance of the phytotoxic and cytogenotoxic effects of these amines but also emphasizes the urgent need for further investigation into contamination originating from cemetery environments. By evaluating the risks associated with necro-leachate, this research is aimed at informing global efforts to protect ecological and public health.

Synthesis and Phytocytogenotoxic Activity of N-Phenyl-2-phenoxyacetamides Derived from Thymol

The excessive use of herbicides has caused a series of problems related to human health, environmental pollution, and an increase in the resistance of plants to commercial herbicides. As an alternative, natural compounds and their semisynthetic derivatives have been widely studied to obtain environmentally friendly and more effective herbicides than the usual ones. In view of these factors, the aim of this work was to synthesize new molecules with herbicidal potential using thymol as a starting material, a natural phenol that has a pronounced phytotoxic effect. Novel N-phenyl-2-thymoxyacetamides were synthesized and characterized by MS and by 1H and 13C NMR. All prepared molecules were subjected to phytotoxic and cytotoxic activity assays using Lactuca sativa L. and Sorghum bicolor L. as model plants. Molecules containing chlorine in the para position of the thymoxy group exhibited phytotoxic and cytogenotoxic effects superior to those of the commercial herbicides 2,4-D and glyphosate.

Allium cepa tests: Exploring bleomycin induced cyto-genotoxicity and altered cell cycle kinetics in root tips meristematic cells

Bleomycin, commonly employed in treating Hodgkin's lymphoma and testicular cancer, is associated with significant pulmonary toxicity. While various studies have assessed the toxic impact of chemotherapeutic agents on aquatic and terrestrial environments, limited data exist on bleomycin's effects, especially concerning higher plants. To address this gap, we utilized the Allium cepa assays, renowned for evaluating chemical and biochemical agents' toxic effects, to investigate bleomycin's impact on the terrestrial ecosystem. Our study aimed to assess bleomycin's cyto-genotoxic effects on A. cepa root tip cells at minimal concentrations (10-40 μg mL-1) and varied exposure durations (2, 4, 6, and 24 h). Analysis of nuclear and mitotic abnormalities in bleomycin-treated A. cepa root tip cells, alongside an acridine orange-ethidium bromide double staining assay, illuminated its influence on cell viability. Additionally, agarose gel electrophoresis determined the drug's potential for DNA degradation, unveiling the underlying mechanisms of cyto-genotoxicity. Results also demonstrated a decline in the mitotic index with increased bleomycin concentrations and exposure time, elevated frequencies of various cyto-genotoxic abnormalities, including sticky chromosomes, chromatid breaks, laggards, bridges, polar deviations, nuclear lesions, and hyperchromasia. The study indicated the potential risks of bleomycin even at low concentrations and brief exposures, highlighting its severe adverse effects on genetic material of plant, potentially contributing to cell death. Consequently, this investigation unveils bleomycin's cyto-genotoxic effects on higher plant system, underscoring its threat to terrestrial ecosystems, particularly upon chronic and unmonitored exposure.

Phytotoxicity of trihalomethanes and trichloroacetic acid on Vigna radiata and Allium cepa plant models

Disinfection by-products (DBPs) are a concern due to their presence in chlorinated wastewater, sewage treatment plant discharge, and surface water, and their potential for environmental toxicity. Despite some attention to their ecotoxicity, little is known about the phytotoxicity of DBPs. This study aimed to evaluate the individual and combined phytotoxicity of four trihalomethanes (THMs: trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and tribromomethane (TBM) and their mixture (THM4)), and trichloroacetic acid (TCAA) using genotoxic and cytotoxic assays. The analysis included seed germination tests using Vigna radiata and root growth tests, mitosis studies, oxidative stress response, chromosomal aberrations (CA), and DNA laddering using Allium cepa. The results showed a progressive increase in root growth inhibition for both plant species as the concentration of DBPs increased. High concentrations of mixtures of four THMs resulted in significant (p < 0.05) antagonistic interactions. The effective concentration (EC50) value for V. radiata was 5655, 3145, 2690, 1465, 3570, and 725 mg/L for TCM, BDCM, DBCM, TBM, THM4, and TCAA, respectively. For A. cepa, the EC50 for the same contaminants was 700, 400, 350, 250, 450, and 105 mg/L, respectively. DBP cytotoxicity was observed through CAs, including C-metaphase, unseparated anaphase, lagging chromosome, sticky metaphase, and bridging. Mitotic depression (MD) increased with dose, reaching up to 54.4% for TCAA (50-500 mg/L). The electrophoresis assay showed DNA fragmentation and shearing, suggesting genotoxicity for some DBPs. The order of phytotoxicity for the tested DBPs was TCAA > TBM > DBCM > BDCM > THM4 > TCM. These findings underscore the need for further research on the phytotoxicity of DBPs, especially given their common use in agricultural practices such as irrigation and the use of sludge as manure.

Phytotoxicity and cytogenetic action mechanism of leaf extracts of Psidium cattleyanum Sabine in plant bioassays

Abstract The search for more environmental friendly herbicides, aiming at the control of agricultural pests, combinated with less harmfulness to human health and the environment has grown. An alternative used by researchers is the application of products of secondary plant metabolism, which are investigated due to their potential bioactivities. Thus, species belonging to the Myrtaceae family are potential in these studies, since this family is recognized for having high biological activity. A species belonging to this genus is Psidium cattleyanum, which has a medicinal effect and its fruits are used in human food. Thus, the objective of this research was to evaluate and compare the phyto-cyto-genotoxicity of aqueous and ethanolic leaf extracts of the specie P. cattleyanum, from plant bioassays, as well as to identify the main classes of compounds present in the extracts. For this, the extracts were prepared, characterized and biological tests were carried out by evaluating, in seeds and seedlings of lettuce and sorghum, the variables: percentage of germination, germination speed index, root growth and aerial growth; and in meristematic lettuce cells the variables: mitotic phases, mitotic index, nuclear alterations and chromosomal alterations. Flavones, flavonones, flavonols, flavononols, flavonoids, alkaloids, resins, xanthones and anthraquinone glycoside were characterized in the ethanolic extract. Both evaluated extracts, in the highest concentration, inhibited the initial plant development. All treatments caused alterations in the mitotic phases and inhibited mitotic index. In addition, the treatments promoted an increase in nuclear and chromosomal alterations. The mechanism of action presented was aneugenic, clastogenic and determined in epigenetic alterations. The ethanolic extract was more cytotoxic, since it had a more expressive effect at a lower concentration. Despite the cytotoxicity of the extracts under study, they promoted alterations at lower levels than the glyphosate positive control.

Toxic risk evaluation of effluents from a swine biodigester in the plant models Lactuca sativa and Allium cepa

Pig farming is recognized as an activity with great polluting potential. The aim was to investigate possible environmental risks of effluents from the stabilization pond (SP) and the raw effluent (RE) from the biodigestion process of swine residues, in different concentrations in the models Lactuca sativa and Allium cepa. Seeds were germinated in different dilutions, 100% (C1), 50% (C2), 25% (C3), 12.5% (C4), 6.25% (C5), 3.12% (C6), 0.78% (C7), and 0.39% (C8). Distilled water was used as the negative control (CN) and trifluralin (0.84 g/L-1) as the positive control. Germination (GR), root growth (RG), cell cycle, and oxidative stress (OS) were analyzed. To assess OS, the activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) and the quantification of glutathione (GSH) and lipid peroxidation (LPO) were analyzed. Data were submitted to ANOVA (one way), followed by the Kruskal-Wallis mean test (P ≤ 0.05). Chemical analysis showed high values of Cu, Fe, Mn, and Zn. Dilutions (C1, C2, C3 RE) and (C1 and C2 SP) inhibited GR and RG of L. sativa and A. cepa than other concentrations. The mitotic index showed a reduction in C5 (RE), C6, and C7 (SP) of L. sativa and C3 and C4 (SP) of A. cepa in relation to CN and higher frequencies of chromosomal alterations. Regarding the OS, only the concentrations of SP treatment showed statistical difference in relation to the NC: in L. sativa model, GSH at (C5 and C8) concentrations and LPO (C7); in A. cepa model, SOD (C3 and C4), GST (C4, C5 and C6), GSH (C5 and C8), and CAT (C3 and C7). The alterations in metabolism are possibly related to the metals, such as zinc and copper, observed in high amounts in the raw waste. The results allowed us to conclude that the raw and stabilization pond effluents offer environmental risks, requiring caution and monitoring in the use of these effluents.

Assessment of Cytogenotoxicity of Plastic Industrial Effluent Using Allium cepa Root Tip Cells

The effects of plastic effluent in Kano Metropolis on cytotoxicity and genotoxicity were examined using a test on Allium cepa root cells. The physicochemical characteristics of industrial wastewater were assessed, and the results showed values that were higher than the required criteria; this implies that the effluent was not treated before to disposal. For 96 hours, a group of 40 onion bulbs was cultivated in various concentrations of plastic effluent: 15, 30, 45, and 60% (v/v). The control was made up of distilled water. Following 96 hours, the four treated root tips from each replication's bulbs were harvested and subjected to the acetoorcein squash technique for cytogenetic analysis. High concentrations of the industrial effluents had severe development retarding effects on the root tips. Root growth was inhibited with EC50 values of 48% after treatment with the effluents in comparison to control. When Allium cepa was exposed to different quantities of plastic effluent, the results of an analysis of variance (ANOVA) showed that the mean root length varied, and this variation was statistically significant (p < 0.05). With rising effluent concentrations, the mitotic index (M.I.) rapidly dropped. Chromosomal abnormalities were caused by the plastic effluent in the root cells of Allium cepa, especially sticky chromosome and binucleated cells being the most frequently seen at lower concentrations of 15%. It was discovered that the compounds found in plastic wastewater could injure live beings as well as harm the environment if not treated. Legal mechanisms must be used to push businesses and manufacturers to switch to environmentally friendly technologies.

Spring water quality monitoring using multiple bioindicators from multiple collection sites

The aim of this study was to examine the water quality of the Extrema River spring in a Brazilian Cerrado area. Three collection sites (P1 - P3) were sampled in the dry and rainy seasons, which are close to industries from different sectors. In the physicochemical analysis, a decrease in dissolved oxygen levels (<5 mg/L) and pH (< 6) at P3 was detected. An increase in heterotrophic bacteria count was recorded at all sites (> 500 colonies/ml). In ecotoxicological analyses, P2 and P3 exhibited toxicity using Vibrio fischeri (> 20%). In evaluating toxicity, the reduction in seed germination was significant utilizing Lactuca sativa at all locations and with Allium cepa only at P2; rootlet length was decreased at P3 on L. sativa and at all sites with A. cepa. In contrast, loss of membrane integrity and mitochondrial function of meristems was adversely affected at all locations using both L. sativa and A. cepa assays. Principal components analysis (PCA) approach indicated that seasonality apparently did not markedly interfere with the obtained data, but it is important to include more collection locations to be evaluated with multiple bioindicators in the spring region. Our data indicate the urgent need for more rigorous programs to monitor the discharge of effluents into water springs.

Photocatalytic removal of 17β-estradiol from water using a novel bimetallic NiCu/Nb2O5 catalyst

The development of effective photocatalytic materials is essential for removing emerging pollutants from aqueous media, such as the hormone 17β-estradiol (E2). In this study, a novel photocatalyst based on niobium pentoxide (Nb2O5) functionalized with nickel (Ni) and copper (Cu) was synthesized for E2 removal. The NiCu/Nb2O5 photocatalyst was prepared using a facile wet impregnation method and characterized by various techniques. The incorporation of Ni and Cu into Nb2O5 reduced the band gap energy from 3.3 to 2.8 eV, enabling efficient utilization of visible light. Moreover, NiCu/Nb2O5 exhibited the highest E2 removal efficiency (82%) under UV-A-assisted conditions at a concentration of 1.5 g L-1. The reaction kinetics were found to follow a second-order model with a rate constant of k = 0.0020 L g-1 min-1, and a plausible reaction mechanism was proposed. Through the study of radical elimination, it was proven that the radical oxidation reaction mechanism predominated in the reaction. The results of the toxicity assays, combined with the TOC parameter, demonstrated the efficacy of photocatalytic degradation in reducing E2. These findings demonstrate the great potential of the NiCu/Nb2O5 photocatalyst for removing persistent pollutants.

Model-Based Analysis of Lactuca sativa Root Growth under the Action of Herbicides in Milli-Channel Arrays with In Situ Imaging

Extracting practical information from the large amounts of data gathered during the live imaging analysis of plant organs is a challenging issue. The present work investigates the use of the logistic growth model to analyze experimental data from root elongation assays performed in milli-fluidic devices with in situ imaging. Lactuca sativa was used as a bioindicator and was subjected to wide concentration ranges of four different herbicides: 2,4-D, atrazine, glyphosate, and paraquat. The model parameters were directly connected to standard indicators of toxicity and plant development, such as the LD50 and the absolute growth rate, respectively. In addition, it was found that realistic predictions of the maximum root length can be achieved about 60 h before the bioassay end point, which could significantly shorten the turnaround time. The combination of milli-fluidic devices, real-time imaging, and model-based data analysis becomes a powerful tool for environmental studies and ecotoxicity testing.

Toxicity of Heavy Metals that Affect Germination, Development and Cell Cycle of Allium cepa L

This study aimed to investigate the impact of heavy metals copper, cadmium, lead, aluminum and nickel, on the growth, physiology, metabolism, and cell cycle of Allium cepa L. Five treatments with increasing concentrations (0, 50, 100, 250, and 500 µM) were applied to the seeds. The results showed that the highest concentrations of copper and cadmium had phytotoxic and biochemical effects on the onion. Additionally, copper concentrations caused an increase in mitodepressive effect and chromosomal abnormalities. Aluminum also induced several chromosomal abnormalities. The study found that Cd > Cu > Pb > Ni > Al and Cu > Al > Ni > Pb > Cd had the highest phytotoxic and cytotoxic potentials, respectively. Furthermore, the UPGMA method revealed three divergent groups. These results suggest that heavy metals, especially copper, have a significant pollution potential when present in high concentrations.

Herbicide and Cytogenotoxic Activity of Inclusion Complexes of Psidium gaudichaudianum Leaf Essential Oil and β-Caryophyllene on 2-Hydroxypropyl-β-cyclodextrin

The present investigation aimed to develop inclusion complexes (ICs) from Psidium gaudichaudianum (GAU) essential oil (EO) and its major compound β-caryophyllene (β-CAR), and to evaluate their herbicidal (against Lolium multiflorum and Bidens pilosa) and cytogenotoxic (on Lactuca sativa) activities. The ICs were obtained using 2-hydroxypropyl-β-cyclodextrin (HPβCD) and they were prepared to avoid or reduce the volatility and degradation of GAU EO and β-CAR. The ICs obtained showed a complexation efficiency of 91.5 and 83.9% for GAU EO and β-CAR, respectively. The IC of GAU EO at a concentration of 3000 µg mL-1 displayed a significant effect against weed species B. pilosa and L. multiflorum. However, the β-CAR IC at a concentration of 3000 µg mL-1 was effective only on L. multiflorum. In addition, the cytogenotoxic activity evaluation revealed that there was a reduction in the mitotic index and an increase in chromosomal abnormalities. The produced ICs were able to protect the EO and β-CAR from volatility and degradation, with a high thermal stability, and they also enabled the solubilization of the EO and β-CAR in water without the addition of an organic solvent. Therefore, it is possible to indicate the obtained products as potential candidates for commercial exploration since the ICs allow the complexed EO to exhibit a more stable chemical constitution than pure EO under storage conditions.

Allium cepa tests: A plant-based tool for the early evaluation of toxicity and genotoxicity of newly synthetized antifungal molecules

Many fungal genera such as Aspergillus, Penicillium, Fusarium and Alternaria are able to produce, among many other metabolites, the aflatoxins, a group of toxic and carcinogenic compounds. To reduce their formation, synthetic fungicides are used as an effective way of intervention. However, the extensive use of such molecules generates long-term residues into the food and the environment. The need of new antifungal molecules, with high specificity and low off-target toxicity is worth. The aim of this study was to evaluate: i) the toxicity and genotoxicity of newly synthesized molecules with a good anti-mycotoxic activity, and ii) the suitability of the Allium cepa multi-endpoint assay as an early screening method for chemicals. Eight compounds were tested for toxicity by using the A. cepa bulb root elongation test and for genotoxicity using the A. cepa bulb mitotic index, micronuclei and chromosome aberrations tests. Three molecules showed no toxicity, while two induced mild toxic effects in roots exposed to the highest dose (100 µM). A more pronounced toxic effect was caused by the other three compounds for which the EC50 was approximately 50 μM. Furthermore, all molecules showed a clear genotoxic activity, both in terms of chromosomal aberrations and micronuclei. Albeit the known good antifungal activity, the different molecules caused strong toxic and genotoxic effects. The results indicate the suitability of experiments with A. cepa as a research model for the evaluation of the toxic and genotoxic activities of new molecules in plants before they are released into the environment.

A comprehensive review of chlorophenols: Fate, toxicology and its treatment

Chlorophenols represent one of the most abundant families of toxic pollutants emerging from various industrial manufacturing units. The toxicity of these chloroderivatives is proportional to the number and position of chlorine atoms on the benzene ring. In the aquatic environment, these pollutants accumulate in the tissues of living organisms, primarily in fishes, inducing mortality at an early embryonic stage. Contemplating the behaviour of such xenobiotics and their prevalence in different environmental components, it is crucial to understand the methods used to remove/degrade the chlorophenol from contaminated environment. The current review describes the different treatment methods and their mechanism towards the degradation of these pollutants. Both abiotic and biotic methods are investigated for the removal of chlorophenols. Chlorophenols are either degraded through photochemical reactions in the natural environment, or microbes, the most diverse communities on earth, perform various metabolic functions to detoxify the environment. Biological treatment is a slow process because of the more complex and stable structure of pollutants. Advanced Oxidation Processes are effective in degrading such organics with enhanced rate and efficiency. Based on their ability to generate hydroxyl radicals, source of energy, catalyst type, etc., different processes such as sonication, ozonation, photocatalysis, and Fenton's process are discussed for the treatment or remediation efficiency towards the degradation of chlorophenols. The review entails both advantages and limitations of treatment methods. The study also focuses on reclamation of chlorophenol-contaminated sites. Different remediation methods are discussed to restore the degraded ecosystem back in its natural condition.

Modulation of phytotoxic and cytogenetic effects of cadmium by humic acid: Findings from a short-term plant-based bioassay

The study of the modulation of the toxicity of heavy metals by coexisting chemicals in the environment is vital for realistic ecological risk assessment. Our study was aimed at determining possible toxicity modulations of Cd by humic acid (HA) using the Allium cepa test system. A. cepa bulbs were exposed to Cd (1 and 5 mg/L) and HA (10 mg/L) individually or in mixtures. The root lengths of the bulbs and cytogenetic endpoints in root meristematic cells, including the mitotic index (MI), nuclear abnormalities (NAs), and chromosomal abnormalities (CAs), were determined. The results revealed that the MIs of A. cepa co-exposed to HA and Cd were significantly recovered by >15% compared with those of A. cepa subjected to Cd-only treatments, and this response was more sensitive than the phytotoxic response (root length). Furthermore, the burden of NAs was significantly decreased in the co-exposed bulbs by >20% compared with bulbs with Cd-only treatments. The frequencies of CAs were also reduced in the bulbs co-exposed to HA and 1 and 5 mg/L Cd by >15 and >25%, respectively, compared with bulbs receiving Cd-only treatments. Therefore, our findings indicated that HA plays a significant protective role in Cd toxicity in A. cepa.

Synthesis of novel glycerol-fluorinated triazole derivatives and evaluation of their phytotoxic and cytogenotoxic activities

The control of weeds in agriculture is mainly conducted with the use of synthetic herbicides. However, environmental and human health concerns and increased resistance of weeds to existing herbicides have increased the pressure on researchers to find new active ingredients for weed control which present low toxicity to non-target organisms, are environmentally safe, and can be applied at low concentrations. It is herein described the synthesis of glycerol-fluorinated triazole derivatives and evaluation of their phytotoxic and cytogenotoxic activities. Starting from glycerol, ten fluorinated triazole derivatives were prepared in four steps. The assessment of them on Lactuca sativa revealed that they present effects on phytotoxic and cytogenotoxic parameters with different degrees of efficiency. The compounds 4a, 4b, 4d, 4e, 4i, and 4j have pre-emergent inhibition behavior, while all the investigated compounds showed post emergent effect. Mechanism of action as clastogenic, aneugenic, and epigenetic were observed in the lettuce root meristematic cells, with alterations as stick chromosome, bridge, delay, c-metaphase, and loss. It is believed that glycerol-fluorinated triazole derivatives possess a scaffold that can be explored towards the development of new chemicals for the control of weed species.

Eco-friendly bioremediation of pollutants from contaminated sewage wastewater using special reference bacterial strain of Bacillus cereus SDN1 and their genotoxicological assessment in Allium cepa

The present study aimed to assess the Bacillus cereus SDN1 native bacterium's ability to clean up contaminated or polluted water. The isolated bacterium was identified by its morphological and biochemical characteristics, which were then confirmed at the genus level. Furthermore, the isolated B. cereus (NCBI accession No: MW828583) was identified genomically by PCR amplifying 16 s rDNA using a universal primer. The phylogenetic analysis of the rDNA sequence was analyzed to determine the taxonomic and evolutionary profile of the isolate of the previously identified Bacillus sp. Besides, B. cereus and the bacterial consortium were treated using sewage wastewater. After 15 days of treatment, the following pollutants or chemicals were reduced: total hardness particles removal varied from 63.33 % to 67.55 %, calcium removal varied from 90 % to 93.33 %, and total nitrate decreased range from 37.77 % to 22.22 %, respectively. Electrical conductivity ranged from 1809 mS/cm to 2500 mS/cm, and pH values ranged from 6.5 to 8.95. The outcome of in-situ remediation results suggested that B. cereus has a noticeable remediation efficiency to the suspended particles. A root tip test was also used to investigate the genotoxicity of treated and untreated sewage-contaminated waters on onion (Allium cepa) root cells. The highest chromosomal aberrations and mitotic inhibition were found in roots exposed to contaminated sewage water, and their results displayed chromosome abnormalities, including disorganized, sticky chain, disturbed metaphase, chromosomal displacement in anaphase, abnormal telophase, spindle disturbances, and binucleate cells observed in A. cepa exposed to untreated contaminated water. The study can thus be applied as a biomarker to detect the genotoxic impacts of sewage water pollution on biota. Furthermore, based on an identified bacterial consortium, this work offers a low-cost and eco-favorable method for treating household effluents.

Lycopene: an antioxidant product reducing dithane toxicity in Allium cepa L

The current study was undertaken to assess the attenuating potential of lycopene against Dithane toxicity in Allium cepa L. roots. A. cepa bulbs were arranged in 6 groups. The control group was treated with tap water while the other groups were treated with 215 mg/L lycopene, 430 mg/L lycopene, 500 mg/L Dithane, 500 mg/L Dithane + 215 mg/L lycopene and 500 mg/L Dithane + 430 mg/L lycopene, respectively. When the treatments were completed, growth inhibition, biochemical, genotoxicity and meristematic cell injury analyses were performed. Lycopene did not cause any toxic effect when applied alone. While rooting percentage, root elongation, weight gain and mitotic index (MI) decreased in response to Dithane exposure, the frequency of micronucleus (MN) and chromosomal abnormalities (CAs) in addition to malondialdehyde (MDA) level and the catalytic activities of superoxide dismutase (SOD) and catalase (CAT) increased. Dithane promoted fragment, sticky chromosome, vagrant chromosome, unequal distribution of chromatin, bridge, nucleus bud and reverse polarization formation in meristem cells. Dithane also provoked meristematic cell injuries, including indistinct appearance of vascular tissue, epidermis cell damage and flattened cell nucleus. Lycopene mitigated all damage types, depending on the lycopene dose applied with Dithane. Hence, the data analysis revealed that lycopene provides exceptional antioxidant protection against the fungicide Dithane, which has devastating toxic potential.

Cytotoxic and genotoxic evaluation of bisphenol S on onion root tips by Allium cepa and comet tests

Bisphenol S (BPS) is an analog of bisphenol A, which is used as substitute of BPA in many products like airport luggage tags, baby bottles, plastics, and epoxy resins etc. Bisphenol S can cause toxic effects in different organisms, i.e., mice, rat, zebrafish, and C.elegans, etc. Bisphenol S is also known as "endocrine disruptor" due to its ability to mimic the endocrine receptors. So, the aim of this study was to evaluate the cytotoxic and genotoxic effects of bisphenol S on meristematic cells present in onion root tips through Allium cepa (A.cepa) and comet tests. Root growth inhibition was evaluated by root growth inhibition assay. Mitotic index (MI) and chromosomal aberrations (CAs) were assessed by A.cepa assay. DNA damage was evaluated by comet assay. Root growth of A.cepa was inhibited due to bisphenol S. LC50 value calculated by root growth inhibition assay for bisphenol S was (2.6±0.63, 50 μg/ml). Mitotic index was reduced, and chromosomal aberrations were observed, i.e., stickiness, polyploidy, and disturbed ana-telophase in anaphase and telophase stages of mitosis. In case of comet assay, DNA damage was increased in statistically significant manner (p ≤ 0.05). It was concluded that bisphenol S constitutes cytotoxic and genotoxic effects on A. cepa root meristematic cells. Moreover, it is suggested to explore more toxicity studies of bisphenol S at molecular level.

Complementary advantages of spent pot lining and coal gangue in the detoxification and valuable components recovery process

As a hazardous solid waste rich in carbon and fluorine, spent pot lining (SPL) is a huge threat to sustainable production and environmental security. As abundant carbon and fluorine resources, the use of such valuable components has great practical and economic significance. Based on the environmental concerns and the component characteristics of SPL, coal gangue (CG), the largest output of solid wastes in the coal-producing industry and rich in aluminum and silicon, was introduced in the utilization and detoxification process of SPL in this work. The substance flow of the co-utilization process presents a circular economy and complementary advantages of SPL and CG. Pure regular fibrous silicon carbides were obtained owing to the synergy effect of SPL and CG. Aluminum from CG and SPL was utilized to prepare dawsonite combined with the sodium from the impurities removal process. Pure cryolite was obtained via mixing wastewater from the silicon carbide purification process and the dawsonite extraction process. Almost all components in SPL and CG were converted into valuable products, and no wastewater and residue was discharged. Thus, a sustainable process of trash to treasure and circular economy for treating CG and SPL was established here with environmental and economically friendly characteristics, which gave a new insight into utilizing wastes with complementary advantages.

Cytogenotoxicity of fifth-generation quaternary ammonium using three plant bioindicators

The investigation aimed to determine the cytogenotoxic effect of fifth-generation quaternary ammonium using three plant species as bioindicators. Bulbs of A. cepa and seeds of L. culinaris and P. sativum were exposed to different concentrations of fifth-generation quaternary ammonium and a control solution of distilled water for 72 h. The results showed that the A. cepa bioindicator presented the greatest reduction in root length at 50 mg L^-1 and no mitotic index at 40 and 50 mg L^-1, reaching 100% mitotic inhibition. Cell abnormalities were present among the three bioindicator species, where the highest index of micronuclei occurred at 50 mg L^-1, being A. cepa the bioindicator with the highest relative rate of abnormality (25.28%). It was concluded that fifth-generation quaternary ammonium, in all treatments, caused a cytogenotoxic effect on the apical meristematic cells of the three species, A. cepa was the most sensitive species.

Genotoxic and cytotoxic effects of pethoxamid herbicide on Allium cepa cells and its molecular docking studies to unravel genotoxicity mechanism

Pethoxamid is chloroacetamide herbicide. Pethoxamid is commonly used to kill different weeds in various crops. Pethoxamid can leach in the water and soil and can cause toxic effects to other non-target species. Current study is therefore aimed to perform the investigation of the cytotoxic and genotoxic effects of pethoxamid on Allium cepa cells.The root growth, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage were assessed through root growth inhibition, A. cepa ana-telophase, and alkaline comet assays, respectively. Furthermore, molecular docking was performed to evaluate binding affinity of pethoxamid on DNA and very-long-chain fatty acid (VLCFA) synthases. In root growth inhibition test, onion root length was statistically significantly decreased in a concentration dependent manner. Concentration- and time-dependent decreases in MI were observed, whereas increase in CAs such as disturbed ana-telophase, chromosome laggards, stickiness, anaphase bridges, and DNA damage was caused by the pethoxamid on A. cepa root cells. Molecular docking revealed that pethoxamid binds selectively to GC-rich regions in the minor groove of the DNA structure and showed remarkable binding affinity against all synthases taking part in the sequential biosynthesis of VLCFAs. It was concluded that the pethoxamid-induced genotoxicity and cytotoxicity may be through multiple binding ability of this herbicide with DNA and VLCFA synthases.

Phytochemical screening and phytocytotoxic effects of the tropical Myrcia vittoriana (Myrtaceae)

We investigated whether essential oil and aqueous and ethanolic extracts from M. vittoriana leaves have phytotoxic effects on the germination and initial development, and cytogenotoxic effects on the cell cycle, of model plants. The essential oil and extracts of M. vittoriana were characterized and used as treatments in phytotoxicity and cytotoxicity tests. The results indicated a reduction in germinative parameters and plant growth, with the higher concentrations of extracts and essential oil having the most evident effects. The cell cycle was also affected with a reduction of the mitotic index and the presence of chromosomal and nuclear alterations. All treatments showed clastogenic and aneugenic modes of action. The results can be associated with the synergistic effects of metabolites found in the extracts and essential oil, mainly the presence of the sesquiterpene germacrene D in the essential oil and of catechins, saponins, and tannins in the extracts. These substances inhibit plant germination and growth, confirming the phytotoxic effects of M. vittoriana in plant models, which should now be tested under field conditions.

Determination of phytotoxicity and cytogenotoxicity due to exposure to particles originating from sugarcane burning using test systems Lactuca sativa L. and Allium cepa L

Sugarcane straw burning generates particulate matter with complex composition resulting in atmosphere pollution. Sugarcane straw sugarcane burning particles (PSSB) contain several chemical compounds that were previously identified to be associated with carcinogenic and mutagenic processes. The aim of the present study was to extract PSSB under lab conditions and subsequently determine phyto- and cytogenotoxicity of these particles using Lactuca sativa L. and Allium cepa L. bioassays. Seeds of lettuce var. Cinderela and onion cv. Vale-Ouro IPA-11 were germinated in Petri dishes containing different concentrations of PSSB at 25, 50, 100, 200 or 300 mg/ml as well as control for 72 hr. Seed germination of lettuce was inhibited by PSSB, in a concentration-dependent manner, accompanied by decreased root growth, suggesting phytotoxic effects. Further, reduction of mitotic index and high number of chromosomal alterations in onion of meristematics cells indicated a cytogenotoxic action attributed to PSSB. Although the chemical composition of PSSB in question has not been determined, the phyto- and cytogenotoxic effects may be linked to the possible presence of polycyclic aromatic hydrocarbons (PAHs), which are were identified as the main constituents of particulate matter resulting from burning of sugarcane straw, in addition to exerting adverse biological effects that might result in mutations and cancer. Data demonstrated that the use of plants bioassays might be an important tool for biomonitoring air quality.

Phyto-genotoxicity assessment of different associations between sludges from Water and Sewage Treatment Plants, before and after the bioremediation process

Water Treatment Plants (WTP) and Sewage Treatment Plants (STP) generate residues known as sludge (WS and SS, respectively). SS and WS present some positive characteristics for reuse in agriculture. The aim of the present study was to evaluate, using the Allium cepa test, the effectiveness of the bioremediation process in the detoxification of SS and WS sludges. In this study, the phytotoxic, cytotoxic, genotoxic, and mutagenic potentials of pure sludge samples (WS and SS) were evaluated, as well as the association of these two sludges with soil (S), before and after the bioremediation process. In the T0 period (before undergoing bioremediation), the SS, SS + S, and SS + WS samples totally inhibited the germination of A. cepa, proving the high phytotoxic potential of these samples. For the T1 period (after 6 months of bioremediation), phytotoxicity was observed for the SS, SS + S, SS + WS, and SS + WS + S samples, but there was not a complete inhibition of germination and radicles growth, allowing the evaluation of the other parameters (cytogenotoxic and mutagenic potential). No cytotoxicity was observed for any sample, both in T0 and T1. As for the genotoxicity parameter, a significant result was observed for the pure WS sample in T0 and for all samples in T1, when compared to NC. The genotoxic alteration most found in meristematic cells exposed to treatments was of binucleated cells. Mutagenic potential was also observed for samples of WS and WS + S in T0. From this study, we can conclude that, after six months of bioremediation, despite the SS phytotoxicity being reduced, all samples were genotoxic to the A. cepa organism test.

Impact of two commercially available hair dyes on germination, morpho-physiology, and biochemistry of Cicer arietinum L. and cytotoxicity study on Allium cepa L. root tip

Contamination of agricultural land and surface water by personal care products and pharmaceutical constituents is a potential environmental threat. The active ingredients of personal care products are life-threatening for users. Present work highlighted the efficacy of the different components of two commercially available hair dyes (synthetic and herbal) on germination, morpho-physiological, biochemical parameters of Cicer arietinum, and cytotoxicity study by Allium cepa root tip. Different treatments such as T1 (control), T2 (cream colour rich), T3 (developer) (The ingredients T2 and T3 are from the same hair dye), T4 (an equal mixture of T2 and T3), and T5 (herbal dye) were considered to run this experiment. The results revealed that all the treatments improve germination with respect to control. Moreover, GSI data suggests that T2 showed the highest germination speed and T3 showed the lowest with respect to other treatments. But root lengths are severely affected by the treatments T3 (100% developer of synthetic hair dye), T4 (an equal mixture of T2 (100% cream colour rich) and T3), and T5 (100% herbal hair dye) with respect to control.T2 also showed the highest root tolerance of all treatments other than control. Similarly, one-way ANOVA results revealed that both fresh weight of roots (p ≤ 0.03) and shoots (p ≤ 0.03) are statistically significant among the different treatments. Moreover, both proline and root ion leakage are higher in the treatment T4 and T5 with respect to control, respectively. On the other hand, the cytotoxicity study highlighted that treatments T3 and T4 showed a higher level of aberration and significantly lower mitotic index compared to treatment T5. Therefore, finally, it may be concluded that both individual and combined forms of ingredients of hair dyes are toxic with respect to cell division and overall plant growth and development.

Protection against the Phytotoxic Effect of Mercury Chloride by Catechin and Quercetin

Plants when exposed to toxic levels of metals can suffer morphological or physiological damage because toxic metals can interact with several vital molecules in the plant. One possibility to remove these contaminants from the environment is through the phytoremediation technique, since secondary metabolites produced by plants can reverse these damages. To evaluate the cytoprotective activity, the dry mass and possible damage to the membranes of Lactuca sativa (lettuce) seedlings subjected to different concentrations of mercury chloride in association with catechin and quercetin in suballelopathic concentration were determined. The coordination of mercury chloride with substances was also evaluated using vibrational spectroscopy (Raman and FTIR). The interaction of the mentioned flavonoids with mercury chloride was evidenced through vibrational spectroscopy. When the metal was associated with catechin and quercetin, there was an increase in dry mass of almost 3 times when compared with the HgCl2 alone, demonstrating that these flavonoids act as cytoprotective agents. However, in the presence of catechin and quercetin, membrane damage caused by mercury chloride has a level similar to that observed in control plants, demonstrating none statistical difference. Comparing the highest concentration with the lowest concentration of the metal associated with quercetin, it can be seen that the intensity of the peaks in this region decreases when the concentration of the metal increases, indicating an interaction between the metallic compound and the flavonoid. In this context, the use of secondary metabolites can be an alternative in the process of remediation of areas contaminated by mercury chloride, as they mitigate the effects of mercury chloride on lettuce seedlings.

Phytotoxic and cytogenotoxic assessment of glyphosate on Lactuca sativa L

The active ingredient glyphosate is the most commercialized herbicide on the world market due to its capability in eliminating weeds. However, it can harm the development of non-target organisms and threaten environmental quality. This study analyzed the effects of potentially toxic concentrations of glyphosate on germination, growth, cell cycle and genomic stability of Lactuca sativa L., and identified the most sensitive variables for assessing the toxicity of this herbicide to this biomonitor. Seeds of L. sativa were germinated in Petri dishes containing a sheet of filter paper moistened with 5 mL of a concentration of glyphosate (1.34, 3.35, 6.70, 10.05, 13.40 mg L-1). Controls consisted of distilled water (negative) and 3 mg L-1 CuSO4 (positive). Macroscopic and microscopic variables were analyzed. The germination of L. sativa was not affected by the concentrations of glyphosate. Root length and shoot height of the plants and the mitotic index decreased from the lowest concentration tested on. The chromosomal anomaly index and frequency of micronuclei increased by 3.2 and 22 times, respectively, with the presence of the lowest concentration of glyphosate compared to the negative control. The observed phytotoxic and cytogenotoxic effects demonstrate the negative influence that glyphosate has on the development of L. sativa. Root length and microscopic variables showed the highest sensitivity. This study warns of the possible harmful effects that glyphosate can have on non-target organisms and suggests greater control over the use of this herbicide to mitigate its environmental impact.

Evaluation of Phytoremediation Potential of Pteris vittata L. on Arsenic Contaminated Soil Using Allium cepa Bioassay

The present study assessed the utility of Allium cepa based cyto-genotoxicity bioassays in evaluating the arsenic toxicity and remediation potential of Pteris vittata on contaminated soil of Lakhimpur-Kheri district. Untreated and P. vittata treated soil extracts were used for cyto-genotoxicity tests in A. cepa. Results showed that P. vittata extracted high concentration of arsenic, which ranged from 220 to 1420 mgkg^-1 in different soils. Cyto-genotoxic assessment of A. cepa showed that extract of P. vittata treated soil had lower cyto-genotoxic effects as compared to untreated soil. A higher mitotic index (10%) while lower mitotic depression (29%), relative abnormality rate (10%), chromosomal aberrations (1%) and micronuclei (2%) were detected in root meristematic cells of A. cepa exposed to remediated soil extract in comparison to untreated soil. The studies provide a simple, rapid and economic cyto-genotoxicity bioassay tool for evaluating toxicity of contaminated soils of contaminated soils as well as revealed the phytoremdiation property of P. vittata against arsenic toxicity.

Cytotoxic and genotoxic effects induced by associated commercial glyphosate and 2,4-D formulations using the Allium cepa bioassay

Studies assessing the toxicity of glyphosate and 2,4-dichlorophenoxyacetic acid mixture are scarce. The aim of this study was to evaluate the cytotoxicity and genotoxicity of the mixture of these herbicides using Allium cepa. Roots were exposed to glyphosate (1.56 and 11.66 mg mL-1), 2,4-D (0.28 and 17.5 mg mL-1) and mixture for 24 h, based on the average concentration applied in the field and the acute reference dose (ARfD) established in Brazil. Both isolated and associated herbicides induced a significative decrease in mitotic index (MI) (P < 0.0001) in all tested concentrations. Regarding the genotoxicity results, 2,4-D and the mixture showed, at concentrations applied in the field, a significative increase of chromosomal anomalies (CA) index compared to control (P < 0.0001) and glyphosate (P = 0.024 and P = 0.0002, respectively). All tested groups from the ARfD showed a significative difference compared to the control group (P < 0.0001), as well as glyphosate and 2,4-D isolated compared to the mixture (P = 0.0005 and P < 0.0001, respectively). The most observed CA were apoptotic bodies, giant cells, and nuclear erosions. We emphasize the need for further studies assessing the toxicity of these herbicides' mixture due to the distinct effects caused in different organisms.

Application of Pteris vittata L. for phytoremediation of arsenic and biomonitoring of the process through cyto-genetic biomarkers of Trigonella foenum-graecum L

The arsenic (As) contamination demands its remediation from the environment which is naturally possible by the application of Pteris vittata L. However, biomonitoring of phytoremediation potential of P. vittata at chromosomal and DNA level is still meager. The present study was designed to biomonitor the phytoremediation efficiency of P. vittata through phytotoxic and cyto-genotoxic biomarkers assessment using Trigonella foenum-graecum L. (Fenugreek; Methi) as test system. Study revealed hyperaccumulation potential of P. vittata which extracted arsenic in its tissues. Biomonitoring evaluation depicted that phytotoxic damage was reduced in Trigonella exposed to remediated soil, which was revealed through reduced electrolyte leakage, hydrogen peroxide and MDA content. Moreover, cyto-genetic endpoints like mitotic depression (44.03%), relative abnormality rate (16.6%) and chromosomal abnormality frequency (1.06%) were also lesser in test plants grown in remediated soil compared to those grown in non-remediated soil. Along with this various chromosomal aberrations like stickiness, breaks, laggards, bridges, fragmentations and micronuclei were also augmented in test plants exposed to non-remediated arsenic enriched soil. It was evident that arsenic enriched soil caused toxicity to plants in dose-dependent manner that was assessable through the analysis of biochemical parameters and cyto-genetic biomarkers. The cyto-genetic biomarkers are very efficient, simple and non-expensive tools to biomonitor arsenic toxicity at chromosomal as well as DNA level to assess the remediation potential of P. vittata in field conditions.

Heterogeneous photocatalysis of moxifloxacin at a pilot solar compound parabolic collector: Elimination of the genotoxicity

Photocatalysis has been applied for the elimination or reduction concentration of emerging pollutants in water. One of them, is the moxifloxacin (MOX), a fluoroquinolone that have a potential to develop resistant bacteria and have been present toxicity. The MOX achieves the environment due to inefficient wastewater treatment and incorrect disposal. Aiming to find a sustainable solution for photocatalytic process, compound parabolic concentrator (CPC) reactors have been proposed. In this sense, the present study investigates the application of CPC reactor for the degradation of MOX using sunlight and artificial light (UV-A lamp). In addition, the acute toxicity for L. sativa seeds and A. cepa bulbs, as well as the MOX cytotoxicity and genotoxicity for A. cepa root were investigated before and after treatment. The MOX degradation was around 65% using the sunlight and 44% with the artificial light. This difference was due to the kind of incident radiation (direct and diffuse), as well as the type of radiation (visible and/or ultraviolet) used in the processes. For L. sativa the acute toxicity was eliminated after MOX treatment using sunlight. A. cepa root length increased before the treatment and reduced significantly after it, what can indicate hormesis occurrence. MOX cytotoxicity was not observed. In contrast, genotoxicity assays showed high frequency of chromosomal aberrations for MOX solution, indicating elevated genotoxicity that was eliminated after solar treatment. The transformation products of MOX after CPC reactor solar treatment did not show cytotoxicity and genotoxicity in A. cepa and acute toxicity in L. Sativa. The results indicates that photocatalysis in a CPC solar reactor is efficient for MOX toxicity removal in the treated solutions.

Bioactivity and molecular properties of Phenoxyacetic Acids Derived from Eugenol and Guaiacol compared to the herbicide 2,4-D

Herbicides are agrochemicals applied in the control of weeds. With the frequent and repetitive use of these substances, serious problems have been reported. Compounds of natural origin and their derivatives are attractive options to obtain new compounds with herbicidal properties. By aiming to develop compounds with potentiated herbicidal activity, phenoxyacetic acids were synthesized from eugenol and guaiacol. The synthesized compounds were characterized and the herbicidal potential of phenoxyacetic acids and precursors was evaluated through bioassays regarding the germination and initial development of Lactuca sativa and Sorghum bicolor seedlings, with the induction of DNA damage. The induction of changes in the mitotic cycle of meristematic cells of roots of L. sativa was also analyzed. At the concentration of 3 mmol L-1, phenols and their respective phenoxyacetic acids presented phytotoxic and cytotoxic activities in L. sativa and S. bicolor. Eugenol and guaiacol also presented genotoxic action in L. sativa. The toxic effect of eugenoxyacetic acid was more pronounced in L. sativa than in S. bicolor, similar to the commercial 2,4-D herbicide. Molecular properties of the phenols and their derivatives phenoxyacetic acids were compared with the ones obtained for the herbicide 2,4-D, where it was found a correlation between their molecular properties and bioactivity.

Bioassays to screen the toxicity in drinking water samples collected in Brazilian rural area

Agriculture activities have increased the concentration of pesticides and metals in the environment. The excessive use of pesticides can generate an environmental impact and contribute to the development of human diseases. This study aimed to determine the presence of pesticides and metals in water samples collected in the Brazilian rural area in two different periods (before and after pesticide application) and to evaluate the alternative bioassays Lactuca sativa, Allium cepa, and Caenorhabditis elegans to monitoring toxicity in human drinking water samples. Eight sites in the rural area were selected and water samples were collected in two different periods of the year (before and after pesticide application). The presence of the pesticides was determinated by ultra-high performance liquid chromatography-tandem mass spectrometry and metals by inductively coupled plasma mass spectrometry. The potential toxicity of the water samples was performed with three different alternatives in vivo models (L. sativa, A. cepa, and C. elegans). Fifty-seven pesticides were analyzed and, according to the results, the most found ones were clomazone, atrazine, tebuconazole, metconazole, pyrimethanil, and carbofuran-3-hydroxide, which is a metabolic degradation product of insecticide carbofuran. The most detected metals were Cu, Cr, Mg, Fe, and Mn. The assays with L. sativa and A. cepa showed alterations in the period after pesticide application, while C. elegans presented changes in both periods compared to the same collection sites. These results indicate that bioassays, especially C. elegans, could be complementary and useful tools for monitoring the toxicity in drinking water samples.

Cytotoxic and genotoxic evaluation of copper oxychloride through Allium test and molecular docking studies

Copper oxychloride gained great importance due to its broad-spectrum antifungal action to combat various fungal diseases of plants. However, excess quantity of cupric fungicides on plants causes enzymatic changes and toxic effects. Thus, the current study was aimed to investigate the cytotoxicity and genotoxicity of copper oxychloride on Allium cepa root cells. The root growth, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage were assessed through root growth inhibition, A. cepa ana-telophase, and alkaline comet assays. Furthermore, molecular docking was performed to evaluate binding affinities of two copper oxychloride polymorphs (atacamite and paratacamite) on DNA. In root growth inhibition test, onion root length was statistically significantly decreased by changing the copper oxychloride concentration from lower (2.64±0.11 cm) to higher (0.92±0.12 cm). Concentration- and time-dependent decrease in MI was observed whereas increase in CAs such as disturbed ana-telophase, chromosome laggards, stickiness, anaphase bridges, and DNA damage were caused by the copper oxychloride on A. cepa root cells. Molecular docking results revealed that the two main polymorphs of copper oxychloride (atacamite and paratacamite) bind selectively to G and C nucleotides on the B-DNA structure. It is concluded that the atacamite- and paratacamite-induced DNA damage may be through minor groove recognition and intercalation. Findings of the current study revealed the cytotoxic and genotoxic effects of copper oxychloride on A. cepa root cells. However, further studies should be carried out at the molecular level to reveal the cyto-genotoxic mechanism of action of copper oxychloride in detail.

Cytotoxic and genotoxic effects of clopyralid herbicide on Allium cepa roots

Clopyralid is one of the synthetic pyridine-carboxylate auxin herbicides and used to control perennial and annual broadleaf weeds in wheat, sugar beets, canola, etc. In this study, dose-dependent cytotoxicity and genotoxicity of clopyralid at different concentrations (25, 50, and 100 μg/mL) have been evaluated on the Allium cepa roots. The evaluation has been performed at macroscopic (root growth) and microscopic levels [mitotic index (MI), chromosome aberrations (CAs) in ana-telophase cells, and DNA damage] using root growth inhibition, Allium ana-telophase, and comet tests. The percentage of root growth inhibition and concentration of reducing root growth by 50% (EC₅₀) of clopyralid were determined compared with the negative control by using various concentrations of clopyralid (6.25-1000 μg/L). The 96 h EC₅₀ of clopyralid was recorded as 50 μg/L. The gradual decrease in root growth and the MI reveals the cytotoxic effects of clopyralid. All the tested concentrations of clopyralid induced total CAs (polyploidy, stickiness, anaphase bridges, chromosome laggards, and disturbed ana-telophase) and DNA damage dose and time dependently. These results confirm the cytotoxic and genotoxic effects of clopyralid on non-target organism.

Toxicity reduction of persistent pollutants through the photo-fenton process and radiation/H2O2 using different sources of radiation and neutral pH

The presence of toxic compounds in aquatic bodies is of great concern, and the Fenton, photo-Fenton and radiation/H₂O₂ processes can be applied in the remediation of these compounds due to their efficiency and advantages. However, these processes need to be investigated to make them more viable and environmentally friendly. Thus, the reduction of toxicity was evaluated, through ecotoxicological tests with Artemia salina and Lactuca sativa, of the compounds 2,4-D, diazepam, nicotine and paracetamol (acetaminophen) by the Fenton, photo-Fenton and radiation/H₂O₂ process with UVC, UVA and natural solar radiation at neutral pH with low concentrations of Fe²⁺ and H₂O₂. The UVC/H₂O₂ process was efficient in the degradation of nicotine (74%), the photo-Fenton process was more efficient in the degradation of 2,4-D (82%), diazepam (27%) and paracetamol (85%) using solar radiation, UVA and UVC respectively. The toxicity and total organic carbon (TOC) tests showed a reduction in the toxicity of the compounds after treatment, except for diazepam, which was more resistant to the process, leading to a higher mortality of Artemia salinas (92%) and less relative seed germination of Lactuca sativa (40%).

Integrative analysis in toxicological assessment of the insecticide Malathion in Allium cepa L. system

For many centuries human populations have been suffering and trying to fight with disease-bearing mosquitoes. Emerging and reemerging diseases such as Dengue, Zika, and Chikungunya affect billions of people around the world and recently has been appealing to control with chemical pesticides. Malathion (MT) is one of the main pesticides used against mosquitoes, the vectors of these diseases. This study aimed to assess cytotoxicity and mutagenicity of the malathion for the bioindicator Allium cepa L. using a multivariate and integrative approach. Moreover, an appendix table was compiled with all available literature of insecticides assessed by the Allium cepa system to support our discussion. Exposures during 48h to 0.5 mg mL-1 and 1.0 mg mL-1 MT were compared to the negative control (distilled water) and positive control (MMS solution at 10 mg L-1). The presence of chromosomal aberrations, micronuclei frequency, and mitotic index abnormalities was evaluated. Anaphase bridges were the alterations with higher incidence and presented a significantly elevated rate in the concentration of 0.5 mg mL-1, including when compared to the positive control. The integrative discriminant analysis summarizes that MT in assessed concentrations presented effects like the positive control, corroborating its potential of toxicity to DNA. Therefore, it is concluded that MT in its pure composition and in realistic concentrations used, has genotoxic potential in the biological assessment of A. cepa cells. The multivariate integrative analysis was fundamental to show a whole response of all data, providing a global view of the effect of MT on DNA.

Ecotoxicological risk assessment of pentachlorophenol, an emerging DBP to plants: evaluation of oxidative stress and antioxidant responses

Chlorophenols are not only noticed in an effluvium of industries but also can emerge from the water treatment plants for domestic supply which poses a high threat for crop production and human health. Therefore, research on their risks to ecosystem and human health via ecotoxicological tests to derivate permissible environmental contaminant concentrations is necessary. The chlorophenols produced in the course of chlorination of potable water is an outcome of natural carboxylic acids/organic material and those chlorophenols occurred as emerging disinfection byproducts (EDBPs). Among chlorophenols, pentachlorophenol (PCP) has been recently identified as one of the important EDBPs. The main objective was to evaluate the PCP-induced genotoxicity and the oxidative damage in two plant species, i.e., Allium cepa and Vigna radiata. Genotoxicity of PCP was examined at three selected concentrations based on EC₅₀ (half-maximal effective concentrations) values in both the plants along with the defense mechanism. EC₅₀ value for A. cepa and V. radiata was 0.7 mg/L and 35 mg/L. Root length inhibition, DNA laddering, lipid peroxidation, H₂O₂ content, and antioxidant enzymatic assays evaluated revealed a dose-dependent response. PCP influenced defense enzyme glutathione peroxidase (GPX) and ascorbate peroxidase (APX) action in both plants and showed deprivement of catalase (CAT) with the increase of PCP concentrations. PCP-invaded toxicity management by these plants implied that A. cepa is more sensitive than V. radiata regarding PCP-induced toxicity.

Toxicogenetic of tebuconazole based fungicide through Lactuca sativa bioassays

The rampant use of pesticides can cause serious environmental problems. They can be contaminating surface water and groundwater, affecting the surrounding micro and macro biota. In this sense, this work aimed to evaluate the effects of a tebuconazole-based fungicide through endpoints accessed in Lactuca sativa bioassays. Germinated-seeds with roots upon 2 mm were treated with a fungicide containing Tebuconazole (TBZ) as active compound. The final concentration of TBZ in the tested solutions were 0.025 (C1); 0.05 (C2); 0.1 (C3); 0.2 (C4) and 0.4 g/L (C5). L. sativa roots were exposed for 24 h to these solutions and Petri dishes containing the treated seeds were kept in incubation chamber at 24 °C. Two positive controls (PC,) the herbicide trifluralin (0.84 mg/L) and Methanesulfonate (4 ×10-4 mol/L), were applied. Distilled water was negative control (NC). The following endpoints were analyzed: root growth (RG), cytogenotoxic potential by cell cycle analysis, induction of DNA damage through TUNEL and comet assays. The obtained data were submitted to one-way variance analysis (ANOVA) and then to Tukey or Kruskal Wallis (P < 0.05) tests. The concentrations (C1, C2, C4 and C5) affected negatively the RG of L. sativa, in comparison with the NC. The mitotic index was reduced by 25% from NC to C1 and in the rest of treatments it did not present significant modifications. However, from C3 to C5 great amount of chromosome alterations were observed, in comparison with the NC. TBZ-based fungicide also induced DNA fragmentation as measured by TUNEL and comet assays. Thus, TBZ-based fungicide in some concentrations can have phytotoxic, cytotoxic and genotoxic effects in roots and meristematic cells of L. sativa.