Seeds’ physicochemical traits and mucilage protection against aluminum effect during germination and root elongation as important factors in a biofuel seed crop (Ricinus communis)

We determined the length, volume, dry biomass, and density in seeds of five castor bean cultivars and verified notable physicochemical trait differences. Seeds were then subjected to different toxic aluminum (Al) concentrations to evaluate germination, relative root elongation, and the role of root apices’ rhizosphere mucilage layer. Seeds’ physicochemical traits were associated with Al toxicity responses, and the absence of Al in cotyledons near to the embryo was revealed by Al-hematoxylin staining, indicating that Al did not induce significant germination reduction rates between cultivars. However, in the more sensitive cultivar, Al was found around the embryo, contributing to subsequent growth inhibition. After this, to investigate the role of mucilage in Al tolerance, an assay was conducted using NH₄Cl to remove root mucilage before or after exposure to different Al concentrations. Sequentially, the roots were stained with hematoxylin and a quantitative analysis of staining intensity was obtained. These results revealed the significant contribution of the mucilage layer to Al toxicity responses in castor bean seedlings. Root growth elongation under Al toxicity confirmed the role of the mucilage layer, which jointly indicated the differential Al tolerance between cultivars and an efficient Al-exclusion mechanism in the tolerant cultivar.     

Production of biodiesel from waste frying oils

Waste frying oils transesterification was studied with the purpose of achieving the best conditions for biodiesel production. Transesterification reactions were carried out for 1 h using waste frying oils (WFOs), methanol, and sodium hydroxide as catalyst. In order to determine the best conditions for biodiesel production, a series of experiments were carried out, using methanol/WFO molar ratios between 3.6 and 5.4 and catalyst/WFO weight ratios between 0.2% and 1.0%. For oils with an acid value of 0.42 mg KOH/g, results show that a methanol/WFO ratio of 4.8 and a catalyst/WFO ratio of 0.6% gives the highest yield of methyl esters. Furthermore, an increase in the amount of methanol or catalyst quantity seems to simplify the separation/purification of the methyl esters phase, as showed by a viscosity reduction and an increasing purity to values higher than 98% for methyl esters phase.     

Solanum nigrum L. weed plants as a remediation tool for metalaxyl-polluted effluents and soils

In this work, the phytoremediation potential of metalaxyl, a commonly used persistent, mobile and leachy fungicide, by Solanum nigrum L. plants was studied. The study revealed that this plant species can be used as an excellent metalaxyl phytoremediation tool, thus providing a cost effective and environmentally friendly clean technology for the decontamination of sites and effluents. As it can be sowed directly in the remediation site, is able to complete its life cycle without suffering major stress. Because it accumulates high amounts of the fungicide in the aboveground tissues, enables its concentration and proper disposal by cutting off the corresponding plant part. The study also suggests that the tolerance to metalaxyl is due to a suitable antioxidant response comprising proline accumulation and guaiacol peroxidase and glutathione-S-transferase enhanced activities, that reduce oxidative damage to the plant organs.     

Multivariate toxicity profiles and QSAR modeling of non-dioxin-like PCBs--an investigation of in vitro screening data from ultra-pure congeners

The non-dioxin-like PCBs (NDL-PCBs) found in food and human samples have a complex spectrum of adverse effects, but lack a detailed risk assessment. The toxicity profiles of 21 carefully selected PCBs (19 NDL-PCBs) were identified by in vitro screening in 17 different assays on specific endpoints related to neurotoxicity, endocrine disruption and tumor promotion. To ensure that the test results were not affected by polychlorinated dioxins, dibenzofurans or DL-PCB contaminants, the NDL-PCB congeners were thoroughly purified before testing. Principal component analysis (PCA) was used to derive general toxicity profiles from the in vitro screening data. The toxicity profiles indicated different structure-activity relationships (SAR) and distinct mechanisms of action. The analysis also indicated that the NDL-PCBs could be divided into two groups. The first group included generally smaller, ortho-substituted congeners, comprising PCB 28, 47, 51, 52, 53, 95, 100, 101, 104 and 136, with PCB 95, 101 and 136 as generally being most active. The second group comprising PCB 19, 74, 118, 122, 128, 138, 153, 170, 180 and 190 had lower biological activity in many of the assays, except for three endocrine-related assays. The most abundant congeners, PCB 138, 153, 170, 180 and 190, cluster in the second group, and thereby show similar SAR. Two quantitative structure-activity relationship (QSAR) models could be developed that added information to the SAR and could aid in risk assessments of NDL-PCBs. The QSAR models predicted a number of congeners as active and among these e.g., PCB 18, 25, 45 and 49 have been found in food or human samples.     

Determination of the dialdehyde glyoxal in workroom air-development of personal sampling methodology

The dialdehyde glyoxal (ethanedial) is an increasingly used industrial chemical with potential occupational health risks. This study describes the development of a personal sampling methodology for the determination of glyoxal in workroom air. Among the compounds evaluated as derivatizing agents; N-methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH), 1,2-phenylenediamine (OPDA), 1-dimethylaminonaphthalene-5-sulfonylhydrazine (dansylhydrazine, DNSH) and 2,4-dinitrophenylhydrazine (DNPH), DNPH was the only reagent that was suitable. Several different samplers were evaluated for sampling efficiency of glyoxal in workroom air using DNPH as derivatizing agent; in-house DNPH coated silica particles packed in two different types of glass tubes, impingers containing acidified DNPH solution, filter cassettes containing glass fibre filters coated with DNPH, a commercially available solid phase cartridge sampler originally developed for formaldehyde sampling (Waters Sep-Pak DNPH-silica cartridge), and the commercially available SKC UMEx 100 passive sampler originally developed for formaldehyde sampling. Aldehyde atmospheres for sampler evaluation were generated with an in-house made vapour atmosphere generator coupled to a sampling unit, with the possibility of parallel sampling. The resulting glyoxal-DNPH derivative was determined using both LC-UV and LC-APCI-MS with negative ionization. By far, the highest recovery of glyoxal was obtained employing one of the in-house DNPH coated silica samplers (93%, RSD = 3.6%, n = 12).     

Evaluating global interest in biodiversity and conservation

The first target of the Convention for Biological Diversity (Aichi target 1) was to increase public awareness of the values of biodiversity and actions needed to conserve it—a key prerequisite for other conservation targets. Monitoring success in achieving this target at a global scale has been difficult; however, increased digitization of human life in recent decades has made it easier to measure people's interests at an unprecedented scale and allows for a more comprehensive evaluation of Aichi target 1 than previously attempted. We used Google search volume data for over a thousand search terms related to different aspects of biodiversity and conservation to evaluate global interest in biodiversity and its conservation. We also investigated the correlation of interest in biodiversity and conservation across countries to variables related to biodiversity, economy, demography, research, education, internet use, and presence of environmental organizations. From 2013 to 2020, global searches for biodiversity components increased, driven mostly by searches for charismatic fauna (59% of searches were for mammal species). Searches for conservation actions, driven mostly by searches for national parks, decreased since 2019, likely due to the COVID-19 pandemic. Economic inequality was negatively correlated with interest in biodiversity and conservation, whereas purchasing power was indirectly positively correlated with higher levels of education and research. Our results suggest partial success toward achieving Aichi target 1 in that interest in biodiversity increased widely, but not for conservation. We suggest that increased outreach and education efforts aimed at neglected aspects of biodiversity and conservation are still needed. Popular topics in biodiversity and conservation could be leveraged to increase awareness of other topics with attention to local socioeconomic contexts.     

Trace elements in fish and oysters from Sepetiba Bay (Rio de Janeiro – Brazil) determined by total reflection X-ray fluorescence using synchrotron radiation

Trace elements were determined in fish and oysters from Sepetiba Bay, Brazil, by total reflection Xray fluorescence using synchrotron radiation (SRTXRF). Cr, Mn, Fe, Ni, Cu, Zn and Se were determined in fish muscles and organs and in oyster soft tissue. SRTXRF was shown to be a good tool for the analysis of trace elements from biological tissue samples. Overall, the levels of the analysed metals were higher in oysters than in the fish samples. Metals were not uniformly distributed throughout the body of the analysed fish. The detected concentrations of Cr, Zn and Se were very high in some samples, surpassing the maximum limits established by Brazilian legislation.     

A multi-integrated approach on toxicity effects of engineered TiO2 nanoparticles

The new properties of engineered nanoparticles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applications, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation of nanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO₂ nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO₂ nanoparticles (Aeroxide® P25), two phase composition of anatase (65%) and rutile (35%) with an average particle size value of 27.6±11 nm were used. Results on the EC₅₀ for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease (p<0.05) after 14 days of exposure for all tested concentrations. The presence of TiO₂ nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.     

Assessment of organic and inorganic contaminants in sediments of an urban tropical eutrophic reservoir

Although the Ibirité reservoir (an urban tropical eutrophic reservoir) has been the recipient of the discharge of a large volume of raw urban sewage, the key cause of ecosystem degradation has been historically solely attributed to the discharge of effluents from an oil refinery. This fact motivated an investigation to unravel the compositions of contaminants in the sediments to evaluate their distributions, possible sources, and potential impacts on sediment–water quality. The concentrations of polycyclic aromatic and aliphatic hydrocarbons and of metals and metalloids were, in general, significantly lower than some selected polluted sites used for comparison. Calculated distribution indexes showed that the hydrocarbon sources were petrogenic, pyrogenic, and biogenic. Only a few PAHs exceeded the threshold effects level (TEL) guideline. Industrial activities are the presumed sources of metals and metalloids except for copper, which is from copper sulfate used as algaecide in the reservoir. The bioavailable concentrations of some metal and metalloid exceeded the TEL–PEL guidelines. The acid volatile sulfide concentration was greater than that of the simultaneously extracted metals in the clayey–silty reservoir sediments, whereas the opposite result was observed for the sandy sediments of the tributaries. The sediment interstitial water toxic units were >1 for metals, thus indicating that metals are potentially toxic to the benthos. Considering the data set generated in this study, it can be concluded that the degradation of Ibirité reservoir and its tributaries cannot be solely attributed to the input of hydrocarbons, but predominantly to the discharge of raw urban sewage and effluents from other industrial sources.     

Does fungicide application in vineyards induce resistance to medical azoles in Aspergillus species?

This study assessed if the use of sterol demethylase inhibitor fungicides in vineyard production can induce resistance to azoles in Aspergillus strains and if it can induce selection of resistant species. We also tried to identify the Aspergillus species most prevalent in the vineyards. Two vineyards from northern Portugal were selected from “Vinhos Verdes” and “Douro” regions. The vineyards were divided into plots that were treated or not with penconazole (PEN). In each vineyard, air, soil, and plant samples were collected at three different times. The strains of Aspergillus spp. were isolated and identified by morphological and molecular techniques. We identified 46 Aspergillus section Nigri, eight Aspergillus fumigatus, seven Aspergillus lentulus, four Aspergillus wentii, two Aspergillus flavus, two Aspergillus terreus, one Aspergillus calidoustus, one Aspergillus westerdijkiae, one Aspergillus tamarii, and one Eurotium amstelodami. Aspergillus strains were evaluated for their susceptibility to medical azoles used in human therapy (itraconazole, posaconazole, and voriconazole) and to agricultural azoles (PEN) used in the prevention and treatment of plant diseases. The isolates showed moderate susceptibility to voriconazole. We did not observe any decrease of susceptibility to the medical azoles tested throughout the testing period in any of the treated plots, although some of the resistant species were isolated from there.