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.

Water assessment of the Itapemirim River/Espírito Santo (Brazil): abiotic and toxicogenetic aspects.

The Itapemirim River is considered one of the most important water resources in the state of Espírito Santo, Brazil. However, environmental problems due to continuous anthropogenic contamination are threatening its potential use. This study assessed water quality by analyzing abiotic and toxicogenetic aspects of the water from four stations along the river. Samples were collected in both dry and rainy seasons. Most of the abiotic variables were below the threshold established by CONAMA Resolution No. 357/2005, and so were most of the metals. However, Al and Cu contents were above those allowed by legislation, ranging from 0.2 to 0.9 mg/L. Regarding toxicogenetic aspects, genotoxic effects were observed in meristematic cells of Allium cepa, in micronucleus test and comet assay of Oreochromis niloticus, and CHO-K1 cells. Mutagenic effects were significant at RI 02 (0.34), RI 03 (0.46), and RI 04 (0.12) stations on the first campaign in A. cepa F1 cells, compared to the negative control (0.0). The second campaign revealed the same results, but with the addition of samples from RI 01 (0.17) and RI 03 (0.18) showing mutagenicity in the micronucleus test with fish erythrocytes when compared to the negative control (0.3). Essentially, all the samples evaluated in both campaigns showed damage in A. cepa, O. niloticus, and CHO-K1 cells, thus demonstrating that the water quality of the Itapemirim River is compromised and requires action plans for its recovery.

Effects of humic acids from landfill leachate on plants: An integrated approach using chemical, biochemical and cytogenetic analysis.

Biological process treatment of landfill leachate produces a significant amount of sludge, characterized by high levels of organic matter from which humic acids are known to activate several enzymes of energy metabolism, stimulating plant growth. This study aimed to characterize humic acids extracted from landfill sludge and assess the effects on plants exposed to different concentrations (0.5, 1, 2 and 4 mM C L-1) by chemical and biological analysis, to elucidate the influence of such organic material and minimize potential risks of using sludge in natura. Landfill humic acids showed high carbon and nitrogen levels, which may represent an important source of nutrients for plants. Biochemical analysis demonstrated an increase of enzyme activity, especially H+-ATPase in 2 mM C L-1 landfill humic acid. Additionally, cytogenetic alterations were observed in meristematic and F1 cells, through nuclear abnormalities and micronuclei. Multivariate statistical analysis provided integration of physical, chemical and biological data. Despite all the nutritional benefits of humic acids and their activation of plant antioxidant systems, the observed biological effects showed concerning levels of mutagenicity.

Water quality of a coastal lagoon (ES, Brazil): abiotic aspects, cytogenetic damage, and phytoplankton dynamics.

Assessment of water resources requires interdisciplinary studies that include multiple ecosystem aspects. This study evaluated the water quality of Juara Lagoon (ES, Brazil) based on physical and chemical variables, cytogenetic responses in Allium cepa and phytoplankton dynamics. Three sampling sites were defined and water samples were collected during two sampling periods. Analyses such as determination of photic zone, conductivity, and concentrations of nutrients and metals were conducted as well as cytotoxic, mutagenic, and genotoxic potentials using A. cepa test. The main attributes of phytoplankton community, such as total richness, total density, density by class, dominance, and diversity, were also evaluated. Results have revealed that Juara Lagoon has signs of artificial eutrophication at two sampling sites due to high levels of total phosphorus and ammonia nitrogen. Cytotoxic, genotoxic, and mutagenic potentials were detected as well as high concentrations of Fe and Mn. Furthermore, 165 phytoplankton taxa were recorded, with highest richness in Chlorophyceae and Cyanophyceae classes. In addition, Cyanophyceae presented as the highest density class. A. cepa test and phytoplankton community evaluation indicated that the ecological quality of Juara Lagoon is compromised.

Matching pollution with adaptive changes in mangrove plants by multivariate statistics. A case study, Rhizophora mangle from four neotropical mangroves in Brazil.

Roots of mangrove trees have an important role in depurating water and sediments by retaining metals that may accumulate in different plant tissues, affecting physiological processes and anatomy. The present study aimed to evaluate adaptive changes in root of Rhizophora mangle in response to different levels of chemical elements (metals/metalloids) in interstitial water and sediments from four neotropical mangroves in Brazil. What sets this study apart from other studies is that we not only investigate adaptive modifications in R. mangle but also changes in environments where this plant grows, evaluating correspondence between physical, chemical and biological issues by a combined set of multivariate statistical methods (pattern recognition). Thus, we looked to match changes in the environment with adaptations in plants. Multivariate statistics highlighted that the lignified periderm and the air gaps are directly related to the environmental contamination. Current results provide new evidences of root anatomical strategies to deal with contaminated environments. Multivariate statistics greatly contributes to extrapolate results from complex data matrixes obtained when analyzing environmental issues, pointing out parameters involved in environmental changes and also evidencing the adaptive response of the exposed biota.

Adaptive plasticity of Laguncularia racemosa in response to different environmental conditions: integrating chemical and biological data by chemometrics.

Mangroves are dynamic environments under constant influence of anthropic contaminants. The correlation between environmental contamination levels and possible changes in the morphology of plants, evaluated by multivariate statistics helps to highlight matching between these variables. This study aimed to evaluate the uptake and translocation of metals and metalloids in roots and leaves as well as the changes induced in both anatomy and histochemistry of roots of Laguncularia racemosa inhabiting two estuaries of Espírito Santo (Brazil) with different pollution degrees. The analysis of 14 elements in interstitial water, sediments and plants followed by multivariate statistics, allowed the differentiation of studied sites, showing good match between levels of elements in the environment with the corresponding in plants. L. racemosa showed variations in their root anatomy in different collection areas, with highest values of cortex/vascular cylinder ratio, periderm thickness and air gap area in Vitória Bay, the most polluted sampling area. These three parameters were also important to differentiate the mangrove areas by linear discriminant analysis. The development stage of aerenchyma in roots reflected the oxygen availability in the water, being found a negative correlation between these variables. The combined use of chemical and biological analyses responded quite well to different pollution scenarios, matching morphological responses to physical and chemical parameters, measured at different partitions within the estuary. Thus, L. racemosa can be confirmed as a reliable sentinel plant for biomonitoring of estuaries impacted by anthropic pollution.