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1.
Environ Technol ; : 1-9, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31587613

RESUMO

Some substances at high concentrations in both the body and the environment can be toxic. The remediation of contaminated environments, for example by metals in toxic concentrations is a fairly current problem. In this way, organic acids of low molecular weight, because they are biodegradable, constitute an alternative potentially for their use in phytoremediation processes. Among these acids, citric acid was chosen to be used in this work due to its suitable binder behaviour, with high stability constants. The purpose of this work was to develop a controlled release of citrate that allows its release to the soil solution to pre-defined concentrations by the system and that this concentration is maintained even if the binder is consumed in the complexation of metals, diluted or percolated. In this way, the system has an additional feature, compared to the conventional controlled release system. The presence of calcium citrate allowed for a slower release of citrate compared to citrate soluble salts or even with calcium citrate directly in solution. The Noyes-Whitney model allowed to explain the effects of pellet sizes and percentages of agar-agar. The pH of the receptor solution and the calcium concentrations used in the preparation of the gels influenced the equilibrium concentration of the citrate, demonstrating the independence of the controlled release process in relation to other variables in the solution. The controlled release system proposed in this work is a promising and very useful system for phytoextraction processes.

2.
Food Res Int ; 125: 108626, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31554076

RESUMO

The efficiencies of two conventional domestic procedures (immersion in pure water and detergent solution at 0.25 and 1%) and two treatments using ozone (immersion in water with bubbling O3 and immersion in ozonated water, both at 1 and 3 mg L-1) were evaluated for the removal of residues of the fungicides azoxystrobin, chlorothalonil and difenoconazole in tomatoes. The fungicides were sprayed on the fruits at the recommended concentration for the crop. The residues in the tomatoes and in the washing solutions were determined by extraction with low-temperature partition techniques and analysis by gas chromatography. More concentrated solutions were more effective in removing pesticide residues. The water bubbled with ozone at 3 mg L-1 was the most efficient treatment for the removal of fungicides, reaching a reduction of 70-90% of the residues. However, the treatments with the lowest concentration of ozone had lower loss of fruit mass during storage.

3.
Chemosphere ; 209: 411-420, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29935469

RESUMO

The Fundão dam collapsed releasing 60 million tons of mining waste into the environment. The mining wastes should be better studied, since some of them are deposited on the alluvial plains soil and at the bottom of the rivers, like sediments, of the region affected. Thus, this work aims to perform the chemical, physical and adsorptive characterization of the samples colleted in region de Paracatu de Baixo. The mining waste has uneven surface, with sizes ranging from 2 to 200 µm, pHPCZ in 6.0. Are composed predominantly by kaolinite, goethite, hematite, gibbsite and quartz. It has been classified as non-hazardous residues. The adsorption studies showed the mining waste have a low Cationic Exchange Capacity. The sorption process was occurs by ion exchange and the kinetics follows the pseudo second order model (R2 > 0.78). The process is endothermic (ΔH in 29.33 kJ mol-1) and spontaneous (ΔG in -24.7 kJ mol-1 at 25 °C). The Langmuir model presented a better fit (R2 > 0.995) to the experimental data. Therefore, the methylene blue can be used as a cation model to predict the behavior of cationic species on the mining waste, with maximum adsorption capacity of 4.42 mg g-1 at 25 °C.


Assuntos
Ferro/química , Azul de Metileno/química , Mineração , Rios/química , Solo/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Adsorção , Brasil , Desastres
4.
J Environ Sci Health B ; 52(12): 850-857, 2017 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-28956709

RESUMO

This study was undertaken to evaluate the effectiveness of several household practices (washing with water or acidic, alkaline, and oxidizing solutions, and peeling) in minimizing pesticide residue contamination of tomatoes, as well as the impact on the quality of the treated fruit. Tests were performed using two systemic fungicides (azoxystrobin and difenoconazole) and one contact fungicide (chlorothalonil). Solid-liquid extraction with low temperature partition (SLE/LTP) and liquid-liquid extraction with low temperature partition (LLE/LTP) were used to prepare the samples for pesticides determination by gas chromatography. Washing the tomatoes with water removed approximately 44% of chlorothalonil, 26% of difenoconazole, and 17% of azoxystrobin. Sodium bicarbonate (5%) and acetic acid (5%) solutions were more efficient, removing between 32 and 83% of the residues, while peeling removed from 68 to 88% of the pesticides. The washing solutions altered some fruit quality parameters, including acidity and chroma, and also caused weight loss. Acetic acid (0.15 and 5%) and hypochlorite (1%) solutions had the greatest effect on these parameters.


Assuntos
Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Lycopersicon esculentum/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Cromatografia Gasosa , Dioxolanos/isolamento & purificação , Fungicidas Industriais/análise , Fungicidas Industriais/isolamento & purificação , Extração Líquido-Líquido , Nitrilos/isolamento & purificação , Pirimidinas/isolamento & purificação , Estrobilurinas/isolamento & purificação , Triazóis/isolamento & purificação
5.
J Environ Manage ; 166: 429-39, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26555099

RESUMO

Searches related to global warming have provided important insights into the response of terrestrial ecosystems, but few have examined the impacts on agricultural crops, particularly those associated with the monitoring of agrotoxin residues. In this context, the agriclimatological zoning is an important tool in the planning and consolidation of crops and should be considered in any initiative that involves such planning. This tool is particularly important in the analysis of agrotoxin residues and may be applied by the Program Analysis of Agrotoxin Residues in Food (PARA) created by the National Health Vigilance Agency of Brazil (ANVISA), which enables greater food security and contributes to the improvement of human health. The aim of this study was to elaborate the current and future agriclimatological zoning for the tomato crop, relating it with the monitoring of samples collected by PARA in Espírito Santo State, Brazil. The results indicate that a temperature increase of 5 °C creates a decrease in apt areas from 37.3% to 4.3%, for a total reduction of 33 percentage points (-88.5%). It is noted that of the 41 producing municipalities, only 26 have apt areas greater than 50%, highlighting the municipalities with apt areas greater than 90%, represented by Mantenópolis (100%), Guaçuí (98.5%), São José do Calçado (97.8%), Irupi (94.4%), Santa Teresa (92.3%), and Marechal Floriano (91.4%). The veracity of agriclimatological zoning is proved by a Kendall rank correlation coefficient of 0.876, indicating that the distribution of the variables of apt areas and productivity are similar at the significance level of 0.05 with a confidence interval 95%. After validation of the agriclimatological zoning for the tomato crop, it is recommended that the PARA should monitor 36 municipalities rather than the current 18, representing an increase of 100%. The methodology can be adjusted to agricultural crops of other countries.


Assuntos
Produtos Agrícolas , Contaminação de Alimentos/análise , Sistemas de Informação Geográfica , Lycopersicon esculentum , Brasil , Ecossistema , Monitoramento Ambiental , Análise de Alimentos/métodos , Aquecimento Global
6.
J Environ Manage ; 159: 158-168, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-26067897

RESUMO

Oil spills are a transnational problem, and establishing a common standard methodology for Oil Spill Risk Assessments (OSRAs) is thus paramount in order to protect marine environments and coastal communities. In this study we firstly identified the strengths and weaknesses of the OSRAs carried out in various parts of the globe. We then searched for a generic and recognized standard, i.e. ISO 31000, in order to design a method to perform OSRAs in a scientific and standard way. The new framework was tested for the Lebanon oil spill that occurred in 2006 employing ensemble oil spill modeling to quantify the risks and uncertainties due to unknown spill characteristics. The application of the framework generated valuable visual instruments for the transparent communication of the risks, replacing the use of risk tolerance levels, and thus highlighting the priority areas to protect in case of an oil spill.


Assuntos
Monitoramento Ambiental/métodos , Poluição por Petróleo , Incerteza , Meio Ambiente , Humanos , Líbano , Modelos Teóricos , Petróleo/análise , Medição de Risco
7.
J Environ Sci Health B ; 49(2): 94-101, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24328541

RESUMO

The effect of ozone fumigation on the reduction of difenoconazole residue on strawberries was studied. Strawberries were immersed in 1.0 L of aqueous solution containing 400 µL of the commercial product (250 g L(-1) of difenoconazole) for 1 min. Then, they were dried and exposed to ozone gas (O3) at concentrations of 0.3, 0.6 and 0.8 mg L(-1) for 1 h. The ozone fumigation treatments reduced the difenoconazole residue on strawberries to concentrations below 0.5 mg kg(-1), which corresponds to a 95% reduction. The strawberries treated with ozone and the control group, which was not treated with ozone, were stored at 4°C for 10 days. Some characteristics of the fruit were monitored throughout this period. Among these, pH, weight loss and total color difference did not change significantly (P > 0.05). The fumigation with ozone significantly affected the soluble solids, titratable acidity and ascorbic acid content (vitamin C) of the strawberries preventing a sharp reduction of these parameters during storage.


Assuntos
Dioxolanos/química , Manipulação de Alimentos/métodos , Fragaria/efeitos dos fármacos , Fumigação/métodos , Fungicidas Industriais/química , Ozônio/química , Triazóis/química , Cromatografia Gasosa , Temperatura
8.
Anal Chim Acta ; 671(1-2): 41-7, 2010 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-20541641

RESUMO

Using a 2(3) experimental design, liquid-liquid extraction with low temperature partitioning (LLE-LTP) was optimized and validated for analysis of three carbamates (aldicarb, carbofuran and carbaryl) in water samples. In this method, 2.0 mL of sample is placed in contact with 4.0 mL of acetonitrile. After agitation, the sample is placed in a freezer for 3 h for phase separation. The organic extract is analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). For validation of the technique, the following figures of merit were evaluated: accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity. Extraction recovery percentages of the carbamates aldicarb, carbofuran and carbaryl were 90%, 95% and 96%, respectively. Even though extremely low volumes of sample and solvent were used, the extraction method was selective and the detection and quantification limits were between 5.0 and 10.0 microg L(-1), and 17.0 and 33.0 microg L(-1), respectively.


Assuntos
Carbamatos , Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Praguicidas , Poluentes Químicos da Água , Aldicarb/análise , Carbamatos/análise , Carbaril/análise , Carbofurano/análise , Fracionamento Químico/métodos , Limite de Detecção , Resíduos de Praguicidas/análise , Poluentes Químicos da Água/análise
9.
Rev. bras. educ. méd ; 33(3): 321-328, jul.-set. 2009. tab
Artigo em Português | LILACS | ID: lil-531844

RESUMO

A carreira médica pode desencadear alterações patológicas na saúde mental, que podem ter início já na graduação. O objetivo deste estudo foi identificar a prevalência de Transtornos Psiquiátricos Menores (TPMe) e a procura por ajuda em estudantes de um curso de Medicina. Trata-se de um estudo transversal, com uma população de 343 estudantes da primeira à quarta série, maiores de 18 anos. Foram realizadas entrevistas, em salas de aula, por meio de dois questionários estruturados, o Self Reporting Questionnaire (SRQ-20) e outro elaborado pelos autores. Análises descritiva, univariada, bivariada e estatística foram utilizadas mediante o programa Microsoft Excel. Os resultados evidenciaram que, entre os acadêmicos com TPMe, 41,6 por cento (a maioria) moravam sozinhos e 75 por cento eram mulheres. Entre os acometidos, 59,2 por cento não conheciam qualquer programa e apenas 9,1 por cento procuraram ajuda. O uso de medicamento foi duas vezes mais prevalente em mulheres com TPMe do que em homens, sendo antidepressivos e ansiolíticos os mais usados. A prevalência de 26,1 por cento de TPMe nos alunos, associada a baixa procura por cuidados e a relatos de automedicação, demonstra a inefetividade dos atuais programas de apoio.


The medical career can trigger pathological changes in mental health that may even begin during undergraduate medical training. The purpose of this study was to identify the prevalence of minor psychiatric disorders (MPD) and the search for counseling by medical students. This was a cross-sectional study of a sample of 343 1st to 4th-year medical students 18 years and older. Interviews were conducted in the classroom using two structured questionnaires, the Self Reporting Questionnaire (SRQ-20) and another prepared by the authors. Descriptive, univariate and bivariate analyses were performed using Microsoft Excel. Among students with MPD, 41.6 percent lived alone and 75.0 percent were women. Among the ill, 59.2 percent were unfamiliar with any counseling program, and only 9.1 percent sought help. Medication for PMD was twice as prevalent in females as compared to males (with antidepressants and anxiolytics as the most frequently used medicines). The 26.1 percent prevalence rate of students with MPD, plus the frequent self-medication and low demand for professional care, demonstrated the ineffectiveness of current psychological support programs.


Assuntos
Humanos , Estudantes de Medicina/psicologia , Saúde Mental , Automedicação
10.
Talanta ; 75(5): 1320-3, 2008 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-18585219

RESUMO

This paper describes a new gas-chromatography with electron capture detection (GC-ECD) method for determination of some pyrethroids in milk samples. The extraction of the pyrethroids was carried out by liquid-liquid extraction with clean-up by precipitation at low temperature, without additional stages for removal of fat interferences. The method was efficient with recoveries of 93.0+/-0.1% for cipermethrin and 84.0+/-0.3% for deltamethrin. The quantification limits were 0.75 microg L(-1) for both pyrethroids. The method was simple, of easy execution, and used only small quantities of organic solvent. After optimization and validation, the method was used for the determination of residues of the pyrethroids cipermethrin and deltamethrin in milk and in lactea drink commercialized in Viçosa (MG, Brazil). Some samples presented contamination with deltamethrin at levels below the maximum contamination limits established by the FAO.


Assuntos
Cromatografia Gasosa/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Inseticidas/análise , Leite/química , Piretrinas/análise , Animais , Brasil , Precipitação Química , Cromatografia Gasosa/instrumentação , Temperatura Baixa , Elétrons , Análise de Alimentos/instrumentação , Humanos , Compostos Orgânicos/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Solventes/química
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