Effects of lead on anatomy,ultrastructure and concentration of nutrients in plants Oxycaryum cubense (Poep. & Kunth) Palla: a species with phytoremediator potential in contaminated watersheds

Lead (Pb) has been highlighted as a major pollutant of both terrestrial and aquatic ecosystems, causing negative impacts to these environments. The concentration of Pb in plants has increased in recent decades, mainly due to anthropogenic activities. This study has as a hypothesis that the species Oxycaryum cubense (Poep. & Kunth) Palla, abundant in aquatic environments, has the potential to be used a phytoremediator. The plants were grown in a hydroponic system with Pb in increasing concentrations (0, 4, 8, 16 and 32 mg l^?1) for 15 days. Inductively coupled mass spectrometer (ICP OES) was used to determine the concentration of mineral nutrients and lead. Optical and transmission electron microscopy were used for the analysis of cellular damage induced by lead in roots and leaves. Ultrastructural alterations were observed as disorganization of thylakoids in the chloroplast and disruption of mitochondrial membranes in cells of leaf tissues of plants subjected to increasing Pb concentrations. There was accumulation of Pb, especially in the root system, affecting the absorption and translocation of some mineral nutrients analysed. In roots, there was reduction in the thickness of the epidermis in plants treated with Pb. This species was shown to be tolerant to the Pb concentrations evaluated, compartmentalizing and accumulating Pb mainly in roots. Due to these results, it may be considered a species with phytoremediation capacity for Pb, with potential rizofiltration of this metallic element in contaminated watersheds.     

Response of Brazilian native trees to acute ozone dose

Ozone (O₃) is a toxic secondary pollutant able to cause an intense oxidative stress that induces visual symptoms on sensitive plant species. Controlled fumigation experiment was conducted with the aim to verify the O₃ sensibility of three tropical species: Piptadenia gonoachanta (Mart.) Macbr. (Fabaceae), Astronium graveolens Jacq. (Anacardiaceae), and Croton floribundus Spreng. (Euphorbiaceae). The microscopical features involved in the oxidative stress were recognized based on specific histochemical analysis. The three species showed visual symptoms, characterized as necrosis and stippling between the veins, mostly visible on the adaxial leaf surface. All the studied species presented hypersensitive-like response (HR-like), and peroxide hydrogen accumulation (H₂O₂) followed by cell death and proanthocyanidin oxidation in P. gonoachanta and A. graveolens. In P. gonoachanta, a decrease in chlorophyll autofluorescence occurred on symptomatic tissues, and in A. graveolens and C. floribundus, a polyphenol compound accumulation occurred. The responses of Brazilian native species were similar to those described for sensitive species from temperate climate, and microscopical markers may be useful for the detection of ozone symptoms in future studies in the field.     

Electrospray Ionization Mass Spectrometry (ESI-MS) monitoring of the photolysis of diazinon in aqueous solution: Degradation route and toxicity of by-products against Artemia salina

The photolytic degradation of diazinon, an organophosphorus pesticide, in aqueous medium under assorted pH values was continuously monitored by direct infusion electrospray ionization mass spectrometry (ESI-MS). The results indicated that the UV radiation was quite efficient in promoting the pesticide degradation at the three pH levels evaluated (5, 7 and 8). The m/z of the most abundant ions observed in the mass spectra (MS), in conjunction with the fragmentation patterns of such ionic species (MS/MS data), made possible the proposition of chemical structures for the main by-products formed. As a result, routes for the photodegradation of diazinon in aqueous solution could thus be suggested. In the assays using Artemia salina (brine shrimp) it was verified that the photodegradation products exhibited much lower toxicity than the primary substrate. Aiming at mimicking the conditions ordinarily found in water treatment plants, an additional series of tests was conducted with a solution containing sodium hypochlorite and diazinon. This solution, when not exposed to UV radiation, exhibited high toxicity against the microorganisms. Under the influence of UV radiation, however, the toxicity rates decreased dramatically. This result is relevant because it points toward the confident application of UV radiation to neutralize the deleterious effects caused by diazinon (and perhaps other organophosphorus pesticides) as well as sodium hypochlorite to the environment.     

Application of Fenton, photo-Fenton, solar photo-Fenton, and UV/H2O2 to degradation of the antineoplastic agent mitoxantrone and toxicological evaluation

In the present study, selected advanced oxidation processes (AOPs)—namely, photo-Fenton (with Fe²⁺, Fe³⁺, and potassium ferrioxalate—FeOx—as iron sources), solar photo-Fenton, Fenton, and UV/H₂O₂—were investigated for degradation of the antineoplastic drug mitoxantrone (MTX), frequently used to treat metastatic breast cancer, skin cancer, and acute leukemia. The results showed that photo-Fenton processes employing Fe(III) and FeOx and the UV/H₂O₂ process were most efficient for mineralizing MTX, with 77, 82, and 90 % of total organic carbon removal, respectively. MTX probably forms a complex with Fe(III), as demonstrated by voltammetric and spectrophotometric measurements. Spectrophotometric titrations suggested that the complex has a 2:1 Fe³⁺:MTX stoichiometric ratio and a complexation constant (K) of 1.47 × 10⁴ M^–1, indicating high MTX affinity for Fe³⁺. Complexation partially inhibits the involvement of iron ions and hence the degradation of MTX during photo-Fenton. The UV/H₂O₂ process is usually slower than the photo-Fenton process, but, in this study, the UV/H₂O₂ process proved to be more efficient due to complexing of MTX with Fe(III). The drug exhibited no cytotoxicity against NIH/3T3 mouse embryonic fibroblast cells when oxidized by UV/H₂O₂ or by UV/H₂O₂/FeOx at the concentrations tested.     

Slope and pig slurry rate may increase the transfer of chemical elements by surface water runoff

There is a need to evaluate the interference of pig slurry rate and the terrain slope in the chemical elements losses from the soil. This work aimed to quantify water and chemical element losses by surface runoff due to terrain slope and pig slurry rate (PS) in two soils with contrasting textures. Two trials were evaluated in 2018 and 2019 in Cambisol and Nitisol. Rates of 0, 22.5, 45, and 90 m³ ha⁻¹ yr⁻¹ of PS were applied superficially in sites with slopes ranging from 10% to 35%. Perennial forage grass Tifton 85 (Cynodon dactylon) was grown as summer crop and ryegrass (Lolium multiflorum) was sown in the cold seasons in a field environment. Were determined the runoff, the volume of water, and chemical elements (Al, Ca, P, Mg, Cd, Cr, Cu, Mn, Fe, Pb, and Zn) lost by the surface runoff after natural rainfall. Increasing land slope elevated water losses substantially, on average 23.4 times in Cambisol and 10.8 times in Nitisol. This increase resulted in average increases of 27.6 and 12.4 times in the losses of the chemical elements analyzed for Cambisol and Nitisol, respectively. There was a reduction in water losses by surface runoff due to increased PS rates applied in both sites. The increased PS rate affected the losses of Cr and Cu in Cambisol and P, Mg, Cd, and Cu in Nitisol. The clayey soil potentiated the water and chemical elements losses by surface runoff in relation to the soil with lower clay content. Regardless of the soil, water and chemical element losses are maximized at higher slopes.     

Organotropism of total mercury (THg) in Cichla pinima,ecological aspects and human consumption in fish from Amazon region,Brazil

Environmental Science and Pollution Research - Specimens of the Cichla pinima are of ecological and economic importance in the Amazon region and are a good bioindicator species of Hg...     

Toxicity evaluation of vinasse and biosolid samples in diplopod midgut: heat shock protein in situ localization

Environmental Science and Pollution Research - Large amounts of residues generated by agricultural, urban and industrial activities are dumped daily on the soil. This practice deserves special...     

Evaluation of chelating and cytoprotective activity of vanillin against the toxic action of mercuric chloride as an alternative for phytoremediation

Environmental Geochemistry and Health - Mercury is widely found in nature, however, in low concentrations, but anthropological activities have increased its concentration considerably. This causes...     

Trace metals in estuarine organisms from a port region in southern Brazil: consumption risk to the local population

Environmental Science and Pollution Research - Metal contamination is a threat to estuarine environments. They can accumulate in the food chain and cause toxic effects on aquatic organisms and...     

Screening of new adsorbents to remove algal organic matter from aqueous solutions: kinetic analyses and reduction of disinfection by-products formation

Environmental Science and Pollution Research - The algal organic matter (AOM) is a problem in water treatment. Although the adsorption process is extensively applied to drinking water treatment,...