A Sustainable Perspective for Macadamia Nutshell Residues Revalorization by Green Composites Development

Journal of Polymers and the Environment - Macadamia is a nut widely used globally in food, personal hygiene products, and human health. After removing the nut, high amounts of the shell residual,...     

Species-specific dinoflagellate vertical distribution in temperature-stratified waters

Thermal stratification is increasing in strength as a result of higher surface water temperature. This could influence the vertical distribution of vertically migrating dinoflagellates. We studied the diel vertical distribution of the dinoflagellates Heterocapsa triquetra and Prorocentrum minimum using stratified laboratory columns with two thermoclines of different strength (ΔT° = 10 or 17 °C), with below cline temperature of 8 °C. Above the thermocline, nutrient depletion simulated the natural summer conditions in the Baltic Sea. Our study shows that H. triquetra and P. minimum can behave differently in terms of their vertical occurrence, both in space and in time when subjected to thermoclines of different strength. Also, both dinoflagellate species showed species-specific distribution patterns. In the ΔT° = 10 °C treatment, H. triquetra cells performed a diel vertical migration (DVM) behavior just above the thermocline, but not in the ΔT° = 17 °C. In the ΔT° = 17 °C, the cells did not migrate and cell densities in the water column decreased over time. Opposing results were observed for P. minimum, where a DVM pattern was found exclusively below the thermocline of ΔT° = 17 °C, while in the ΔT° = 10 °C treatment, no clear DVM pattern was observed, and the highest number of cells were found in the cold bottom water. These results indicate that an increase in thermal stratification can influence species-specific dinoflagellate distribution, behavior, and survival.     

Electrochemical conversion of biomass-derived aldehydes into fine chemicals and hydrogen: A review

Environmental Chemistry Letters - The decrease in fossil fuel usage and the projected 28% increase in the global energy demand by 2040 are calling for advanced methods to convert modern biomass...     

A numerical study of soil cover performance

In the investigation of soil cover design options for final decommissioning of reactive mine waste, it is often necessary to analyze or predict the anticipated cover performance as a function of the cost of implementation, which is governed by the type, number and thickness of the layers in the cover system. An example of such investigation is presented in this study where one-dimensional evaporation from hypothetical moisture-retaining cover systems is simulated to assess the influence of several cover properties and hydrogeologic parameters on performance. The commercially available transient flow model, SoilCover, was used to compute suction and water content profiles for different cover design scenarios. The predicted water content profile and porosity of layers were then used to estimate the oxygen diffusion coefficients of the various layers. The oxygen diffusion coefficients were used to estimate oxygen flux through the cover systems. The oxygen flux was, in turn, related to the maximum acid flux. The studied cover and hydrogeologic parameters included soil type, thickness of barriers, and water table elevation. Two types of infiltration and oxygen barrier and two types of capillary layer with different thicknesses were studied. The water table was either kept constant at the base of the waste (tailings) or dropped by 0.5, 1, 2, and 3m over 120 days. The results showed that the relationship between water table depression and the thickness of capillary layers, on one hand, and desaturation of the infiltration and oxygen barrier, on the other, is not linear. Relationships between oxygen flux and barrier thickness and between cost increase and performance improvement of the studied cover systems are presented. Finally, a method that outlines steps for site-specific and economically feasible design of multi-layer cover systems is introduced.     

Do tailings from the Mariana,MG (Brazil), disaster affect the initial development of millet,maize, and sorghum?

Environmental Science and Pollution Research - The collapse of the Fundão dam in Mariana, MG, in 2015 resulted in the overflow of more than 50 million m3 of mud containing mine tailings,...     

Five years of formaldehyde and acetaldehyde monitoring in the Rio de Janeiro downtown area – Brazil

The fuel matrix used in Brazil is unique around the world. The intensive use of hydrated ethanol, gasohol (gasoline with 25% v/v of ethanol), compressed natural gas (CNG), and biodiesel leads to a peculiar composition of the urban atmosphere. From 1998 to 2002 an increase in formaldehyde levels was observed and since then, a reduction. This work presents a monitoring campaign that was executed from March 2004 to February 2009 by sampling at early morning on every sunny Wednesday for a total of 183 samples. The results indicate a strong reduction in formaldehyde levels from 2004 (average of 135.8 μg m^?3 with SD 28.4 μg m^?3) to 2009 (average of 49.3 μg m^?3 with SD 27.4 μg m^?3). The levels of acetaldehyde showed a slight reduction from 2004 (average of 34.9 μg m^?3 with SD 8.0 μg m^?3) to 2009 (average of 26.8 μg m^?3 with SD 11.5 μg m^?3). Comparing the results with the concurrent evolution of the fleet and of fuel composition indicates that the observed formaldehyde levels could be associated with the increase in ethanol use and in CNG use by engines with improved technology over the first converted CNG engines. Modelling studies using the OZIPR trajectory model and the SAPRC chemical mechanism indicate that formaldehyde is the main ozone precursor in Rio de Janeiro and acetaldehyde is the forth one.     

Pesticide residues in Portuguese strawberries grown in 2009–2010 using integrated pest management and organic farming

Pesticides are among the most widely used chemicals in the world. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticide residues through their diets. Scientists do not yet have a total understanding of the health effects of these pesticide residues. This work aims to determine differences in terms of pesticide residue content in Portuguese strawberries grown using different agriculture practices. The Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation method was conducted and shown to have good performance for multiclass pesticides extraction in strawberries. The screening of 25 pesticides residue was performed by gas chromatography?Ctandem mass spectrometry. In quantitative validation, acceptable performances were achieved with recoveries of 70?C120 and <12?% residual standard deviation for 25 pesticides. Good linearity was obtained for all the target compounds, with highly satisfactory repeatability. The limits of detection were in the range of 0.1?C28???g/kg. The method was applied to analyze strawberry samples from organic and integrated pest management (IPM) practices harvested in 2009?C2010. The results showed the presence of fludioxonil, bifenthrin, mepanipyrim, tolylfluanid, cyprodinil, tetraconazole, and malathion when using IPM below the maximum residue levels.     

Diphenyl diselenide attenuates hepatic and hematologic toxicity induced by chlorpyrifos acute exposure in rats

Purpose

In this study, we investigated the effect of diphenyl diselenide [(PhSe)₂] on chlorpyrifos (CPF)-induced hepatic and hematologic toxicity in rats.

Methods

Rats were pre-treated with (PhSe)₂ (5?mg/kg) via the oral route (oral gavage) once a day for 7?days. On the eighth and ninth days, rats were treated with (PhSe)₂ (5?mg/kg) 30?min prior to CPF (50?mg/kg, by subcutaneous route). The aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase activities were determined in plasma of rats. Lipid peroxidation, protein carbonyl, and non-protein thiol levels as well as catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and gluthatione S-transferase activities were determined in livers of rats. Hematological parameters were also determined.

Results

The results showed that CPF caused hepatic oxidative damage, as demonstrated by an increase in lipid peroxidation and protein carbonyl levels which was associated with a decrease in antioxidant defenses. CPF exposure caused a reduction in the leukocyte, indicating hematologic toxicity. (PhSe)₂ was effective in attenuating these toxic effects caused by CPF exposure in rats.

Conclusions

The results indicated that (PhSe)₂ was effective in protecting the hepatic and hematologic toxicity induced by acute CPF exposure in rats.     

PLA and Montmorilonite Nanocomposites: Properties, Biodegradation and Potential Toxicity

The concern related to solid waste increases efforts to develop products based on biodegradable materials. At present, PLA has one of the highest potentials among biopolyesters, particularly for packaging. However, its application is limited in some fields. In order to optimize PLA properties, organo-modified montmorilonites have been extensively used to obtain nanocomposites. Although PLA nanocomposites studies are widely reported in the literature, there is still few information about the influence of organoclays on de biodegradation process, which is a relevant information, since one of the main purposals related to the final disposal of biopolymers as PLA is composting. Besides, in the last years some research has been conducted in order to evaluate the potential toxicity of montmorilonite, unmodified or organo-modified. Since the use of montmorilonite is expanding in different applications, human exposure and risk assessment are important issues to be investigated. In this context, this review intends to compile available information related to common organoclays used for PLA nanocomposites, its properties, biodegradation analysis and potential toxicity evaluation of nanocomposites, focused on montmorilonite as filler. Two issues of relevance were pointed out. The first is food safety and quality, and the second consideration is the environmental effect.     

Respiration induced by substrate and bacteria diversity after application of diuron,hexazinone, and sulfometuron-methyl alone and in mixture

Abstract

After application, herbicides often reach the soil and affect non-target soil microorganisms, decreasing their population, diversity or affecting metabolic activity. Therefore, laboratory studies were performed to evaluate the effects of diuron, hexazinone and sulfometuron-methyl alone and mixed upon carbon transformation by soil microorganisms in clayey and sandy soils and the effect on bacterial diversity and structure. Control treatment without herbicide application was also performed. Sub-samples from the control and herbicide treatments (10?g – in triplicate) were collected before herbicide application and 7, 14, 28 and 42?days after treatment (DAT), then 1?mL of ¹⁴C-glucose solution was applied. The released ¹⁴CO₂ was trapped in 2?M NaOH solution and the radioactivity was analyzed by liquid scintillation counting (LSC), 12?h after glucose application. The effect of herbicides on bacterial diversity was evaluated by T-RFLP. The experiment was conducted in a complete randomized design. Hexazinone did not affect ¹⁴CO₂ evolution. Diuron showed a greater ¹⁴CO₂ evolution in sandy and clayey soil, while sulfometuron-methyl led to an increase in sandy soil, at 42 DAT. A greater evolution of carbon was observed in the treatment with herbicide mixture in sandy soil, compared with the same treatment in clayey soil or control. However, the herbicide mixture application did not affect the soil biological activity measured by the respiration rate induced by substrate. On the other hand, the herbicide mixtures affected the bacterial diversity in both soils, being the strongest effect to diuron and sulfometuron-methyl in clayey soil and hexazinone in sandy soil.