Effects of the compost of urban refuse in the availability and absorption of heavy metals in lettuce

O lixo é um grande problema ambiental. Sem tratamento, polui solo, águas, plantas e prejudica a qualidade de vida da população. A reciclagem dos materiais inertes e compostagem da fração orgânica do lixo são soluções para este problema. O composto de lixo é aplicado ao solo, visando melhorar sua fertilidade. Entretanto, estes compostos podem apresentar altas concentrações de metais pesados, podendo contaminar solos e plantas e atingir a cadeia alimentar. No Brasil, dados científicos sobre efeitos da utilização do composto na agricultura são escassos. Para obter mais informações, conduziu-se experimento, utilizando-se dois compostos, provindos de Coimbra e Rio de Janeiro, três doses destes compostos (0, 35 e 70 t/ha) e quatro tempos de aplicação antes do plantio (0, 10, 20 e 30 dias) para cultivar alface. Avaliaram-se produção; pH e disponibilidade de Zn, Cu, Mn, Pb e Ni no solo; absorção e acúmulo destes metais pelas plantas; e correlações entre metais extraídos com ácido dietilenotriaminopentacético (DTPA) e acumulados na planta. Resultados mostraram que a produção aumentou com a elevação das doses dos compostos. Os tempos que levaram à máxima produção estão entre 15 e 20 dias. O pH elevou-se com o aumento das doses e diminuiu com o aumento do tempo. As concentrações de Zn, Cu, Pb e Ni disponíveis aumentaram com a elevação das doses, e de Mn manteve-se praticamente constante. Em geral, as concentrações dos metais aumentaram com o aumento do tempo de aplicação. O composto do Rio de Janeiro causou maior incremento na concentração disponível dos metais. Na parte aérea, a concentração de todos os metais aumentou com as doses aplicadas. As concentrações de Cu, Mn e Pb aumentaram até o tempo de 30 dias. A concentração de Zn aumentou até os tempos estimados de 16,9; 19,2; 21,5 dias para 0, 35, 70 t/ha e 18,3 dias para todas as doses, respectivamente, para os compostos do Rio de Janeiro e de Coimbra. A concentração de Ni aumentou linearmente para o composto de Coimbra e até os tempos estimados de 21,5; 28,4; 30 dias para 0, 35, 70 t/ha do composto do Rio de Janeiro. Os coeficientes de correlação entre concentrações disponíveis e acumuladas na planta foram: 0,73; 0,43; 0,80; 0,87 e 0,78, respectivamente, para Zn, Cu, Mn, Pb e Ni. A utilização dos compostos causou aumento nas concentrações dos metais nas plantas, não atingindo, entretanto, os limites permitidos pela legislação brasileira para alimentos. O composto de Coimbra promoveu maior produção e concentrações menores dos metais no solo e na planta, sendo mais indicado como adubo.The refuse is a great environmental problem. Without treatment, it pollutes soil, waters, plants and it harms the quality of life of the population. The recycling of the inert materials and composting of the organic fraction of the refuse are solutions for this problem. The compost of refuse is applied to the soil, seeking to improve the productivity. However, these compost can present high concentrations of heavy metals, could contaminate soils and plants, reaching the alimentary chain. In Brazil, scientific data on effects of the use of the compost in the agriculture, are scarce. To obtain more information, behaved experiment being used two compost (Coimbra and Rio de Janeiro), three doses of the compost (0, 35, 70 t/ha) and four times of application before the plantation (0, 10, 20, 30 days) to cultivate lettuce. Production was evaluated; pH and availability of Zn, Cu, Mn, Pb and Ni in the soil; absorption and accumulation of these metals for the plants and correlations among extracted metals with dietilenotriaminopentacetic acid (DTPA), and accumulated in the plant. Results showed that the production increased with the elevation of the doses of the compost. The times that took to the maximum production are between 15 and 20 days. The pH increased with the increase of the doses and it decreased with the increase of the time. The concentrations of Zn, Cu, Pb and available Ni increased with the elevation of the doses and Mn stayed practically constant. In general, the concentrations of the metals increased with the increase of the time of application. The compost of Rio de Janeiro caused larger increment in the available concentration of the metals. In the plant, the concentration of everybody the metals increase with the applied doses. The concentrations of Cu, Mn and Pb increased until the time of 30 days. The concentration of Zn increased to the esteemed times of 16,9; 19,2; 21,5 days for 0, 35, 70 t/ha and 18,3 days for whole the doses, respectively, for the compost of Rio de Janeiro and of Coimbra. The concentration of Ni increased lineally for the compost of Coimbra and to the esteemed times of 21,5; 28,4; 30 days for 0, 35, 70 t/ha of the compost of Rio de Janeiro. The correlation coefficients among available concentrations and accumulated in the plant they were: 0,73; 0,43; 0,80; 0,87; 0,78, respectively, for Zn, Cu, Mn, Pb, Ni. The use of the compost caused increase in the concentrations of the metals in the plants, not reaching, however, the limits allowed by brazilian legislation. The compost of Coimbra promoted larger produtction and smaller concentrations of the metals in the soil and it plants, being more indicated as fertilizer.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Photoelectrocatalytic oxidation of ethinylestradiol on a Ti/TiO2 electrode : degradation efficiency and search for by-products.

The degradation of ethinylestradiol (EE, an orally bio-active estrogen) in an aqueous-methanolic solution using a Ti/TiO2 thin-film electrode and UV radiation (a photoelectrocatalytic system) was evaluated. Hence, HPLC/UV analysis shows that EE (at 0.34 mmol) is totally consumed after 30 minutes of exposure to the photoelectrocatalytic system in the presence of Na2SO4 (0.1 mol•L−1) and with an applied bias potential of +1.0 V versus the Ag/AgCl reference electrode. Moreover, monitoring by direct infusion electrospray ionization mass spectrometry (ESI-MS) and SPME-GC/ MS (solid phase microextraction coupled with gas chromatography-mass spectrometry) reveals that apparently no degradation products are formed under these conditions. Hence, this study demonstrates that the photoelectrocatalytic system can be efficiently used to promote the complete degradation (and likely mineralization) of this hormone under these conditions

Determination of inorganic elements in teas using inductively coupled plasma optical emission spectrometry and classification with exploratory analysis.

Multivariate optimization was employed to obtain the best conditions of the inductively coupled optical emission spectrometer (ICP OES) (nebulization gas flow rate of 0.47 L min−1 and applied power of 1.36 kW) for the determination of Al, Ba, Ca, Cu, Fe, K, Mg, Na, and Mn in 27 green tea samples. In the hierarchical cluster analysis, it was possible to observe the formation of five different groups (imported Japanese samples, samples without specifications, organically cultivated samples, samples in capsules, and ready-to-drink iced tea samples) besides the separation according to brand. In the principal component analysis we verified that the first four main components explained 99.98 % of the total variance. The ICP OES technique and the exploratory analysis were shown effective tools that can be used jointly in the quality control and classification of green tea samples

Evaluation of signal-to-background and Mg II/Mg I ratios as response for the optimization of rare earth elements determination by inductively coupled plasma optical emission spectrometry.

Elementos terras raras (ETR) fazem parte de um grupo peculiar de elementos químicos e sua determinação em amostras geológicas é importante e complexa, devido às baixas concentrações e problemas com interferências espectrais e não espectrais. Neste trabalho, planejamentos experimentais foram utilizados para otimizar as condições operacionais de um espectrômetro de emissão óptica com plasma indutivamente acoplado (ICP OES) para a determinação de ETR. A razão entre o sinal analítico dos ETR e o sinal de fundo (SBR) e a razão Mg II/Mg I foram avaliadas como respostas na otimização. De acordo com os resultados obtidos, três diferentes condições de operação foram selecionadas e classificadas como robusta, semi-robusta e melhor SBR. Limites de detecção (LOD), SBR e desvio padrão relativo de medidas de uma solução do branco (DPRbranco) foram determinados. Na condição semi-robusta (potência de 1250 W e vazão do gás nebulizador de 0,90 L min−1) foram obtidos LOD e DPRbranco mais baixos que nas outras condições estabelecidas.Rare earth elements (REEs) is a peculiar group of chemical elements. Their determination in geological samples is important and complex due to their low concentrations and problems with spectral and non-spectral interferences. Herein, the operating conditions of an inductively coupled plasma optical emission spectrometer were optimized for the determination of REEs using experimental designs. The signal-to-background ratio (SBR) of the REEs emission signals and the Mg II/Mg I line intensity ratio were evaluated as response functions. According to the results obtained, three different sets of operating conditions were selected and classified as robust, semi robust and best SBR conditions. Limits of detection (LOD), SBR and relative standard deviation of the blank solution (RSDblank) were determined. The semi-robust condition (RF power of 1250 W and nebulizer gas flow rate of 0.90 L min−1) exhibited lower LOD and RSDblank than others tested operating conditions

Fast determination of benzodiazepines in human urine via liquid-liquid extraction with low temperature partitioning and LC-HRMS.

A simple and high-throughput method to simultaneously determine selected benzodiazepines (i.e., diazepam, lorazepam, clonazepam, and bromazepam) in urine was developed and validated. The entire methodology consisted of the applica-tion of an innovative extraction/cleanup procedure, namely liquid-liquid extraction with low-temperature partitioning (LLE-LTP), and analysis by liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS). The LLE-LTP procedure was optimized via factorial design and by evaluating crucial variables, specifically the freez-ing mode (either slow or fast), the urine/acetonitrile volume ratio, and the sample ionic strength. The benzodiazepines were quantified using matrix-matched calibration curves where the following parameters were assessed by validation protocol: in general, linearity range of 17 - 200 μg•L–1 (r > 0.9957); limits of detection lower than 5 μg•L–1; relative standard deviations (RSD) lower than 12.5%; and accuracy ranging from 72.3% to 117%. To test this procedure’s per-formance, the method was applied to determine the content of diazepam in actual urine samples. The validation results obtained for the method demonstrated that the present methodology could be potentially applied in proficient laborato-ries as a routine approach for determining benzodiazepines compounds content in urine