Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Bioactive trace metal distributions and biogeochemical controls in the Southern Ocean

Extensive sampling in many regions of the Southern Ocean has demonstrated that surface water concentrations of dissolved Fe are low enough to limit phytoplankton growth. In contrast, there is currently no evidence that other bioactive elements (e.g., Mn, Zn, Co) are similarly limiting. Although atmospheric input of dissolved Fe to Southern Ocean surface waters appears to be low, resuspension of sediments from shallow regions around islands and the Antarctic coastline can inject significant amounts of Fe into the surrounding waters, stimulating primary production and providing a natural laboratory for studying the response of biological systems to natural Fe fertilization processes. Future work using a multitracer approach across seasonal transitions would be particularly beneficial to quantifying input processes and fluxes. However, it would require the design of new sampling platforms that can accommodate trace metal sampling under extreme weather conditions

Determination of dissolved zinc in seawater using micro-Sequential Injection lab-on-valve with fluorescence detection

This paper introduces the preliminary design and optimization of a micro-Sequential Injection lab-on-valve system (?SI-LOV) with fluorescence detection for the direct determination of trace Zn2+ in an unacidified seawater matrix. The method capitalizes on the sensitivity and selectivity of FluoZin-3, which was originally designed to measure zinc in living cells. The optimum reaction conditions, sources of blank signal and physical parameters of the ?SIA-LOV are evaluated with the requirements of trace metal analysis in mind, namely high sensitivity and low background signals. A detailed investigation of the effect of sample and reagent sequencing on sensitivity is presented for the first time using ?SIA-LOV. We find that the order of sequencing greatly influences peak shape and analytical sensitivity with the highest and smoothest peaks obtained when a large volume of sample (75 ?L) is aspirated last in the sequence prior to flow reversal and detection. The optimized reaction conditions and reagent/sample sequencing protocol yield a detection limit of 0.3 nM Zn2+, high precision (RSD < 2.5%), a linear quantification range up to 40 nM and an analytical cycle of [similar]1 min per sample. This work demonstrates that ?SI-LOV is capable of attaining detection limits that are close to those needed for open ocean determinations of Zn2+ without preconcentration or separation of the analyte from the seawater matrix. The low reagent consumption (50 ?L per sample), full automation and minimal maintenance requirements of ?SI-LOV make it well suited for shipboard analysis and, eventually, for development to meet the pressing need for trace element measurements in unattended locations

Towards chemiluminescence detection in micro-sequential injection lab-on-valve format: A proof of concept based on the reaction between Fe(II) and luminol in seawater

Micro-sequential injection lab-on-valve (µSI-LOV) is a well-established analytical platform for absorbance and fluorescence based assays but its applicability to chemiluminescence detection remains largely unexplored. In this work, we describe a novel fluidic protocol and two distinct strategies for photon collection that enable chemiluminescence detection using µSI-LOV for the first time. To illustrate this proof of concept, we selected the reaction between Fe(II) and luminol and developed a preliminary protocol for Fe(II) determinations in acidified seawater. The optimized fluidic strategy consists of holding 100 µL of the luminol reagent in a confined zone of the LOV and then displacing it with 50 µL of sample while monitoring the chemiluminescent product. Detection is achieved using two strategies: one based on a bifurcated optical fiber and the other based on a customized detection window created by mounting a photomultiplier tube atop of the LOV device. We show that detection is possible using both strategies but that the window strategy yields significantly enhanced sensitivity (355×) due to the larger detection area. In our final experimental conditions and using window detection, it was possible to achieve a limit of detection (LOD) of 1 nmol L?1 and to quantify Fe(II) in acidified seawater samples up to 20.00 nmol L?1 with high precision (RSD<6%). These analytical features combined with the long-term stability of luminol solution and the full automation and low reagent consumption make this approach a promising analytical tool for shipboard analysis of Fe(II). The intrinsic capacity of the LOV to operate at a low microliter level and to handle solid phases also opens up a new avenue for chemiluminescence applications. Moreover, this contribution shows that LOV can be a universal platform for optical detection, capable of absorbance, fluorescence and luminescence measurements in a single instrument setup

Determination of trace zinc in seawater by coupling solid phase extraction and fluorescence detection in the Lab-On-Valve format

By virtue of their compactness, long-term stability, minimal reagent consumption and robustness, miniaturized sequential injection instruments are well suited for automation of assays onboard research ships. However, in order to reach the sensitivity and limit of detection required for open-ocean determinations of trace elements, it is necessary to preconcentrate the analyte prior its derivatization and subsequent detection by fluorescence. In this work, a novel method for the determination of dissolved zinc (Zn) at subnanomolar levels in seawater is described. The proposed method combines, for the first time, automated matrix removal, extraction of the target element, and fluorescence detection within a miniaturized flow manifold, based on the Lab-On-Valve (LOV) concept. The key feature of the microfluidic manipulation of the sample is flow programming, designed to pass sample through a minicolumn where the target analyte and other complexable cations are retained, while the seawater matrix is washed out. Next, zinc is eluted and merged with a Zn selective fluorescent probe (FluoZin-3) at the confluence point of the LOV central channel using two high-precision stepper motor driven pumps that are operated in concert. Finally, the thus formed Zn complex is transported to the LOV flow cell for selective fluorescence measurement. This work describes the characterization and optimization of the method including Solid Phase Extraction using the Toyopearl AF-Chelate-650M resin, and detailed assay protocol controlled by a commercially available software and instrument. The proposed method features a LOD of 0.02 nM, high precision (<3% at 0.1 and 2 nM Zn levels), an assay cycle of 13 min and a reagent consumption of 150 mL FluoZin-3 per sample, which makes the method highly suitable for oceanographic shipboard analysis. The accuracy of the method has been validated through the analysis of seawater reference standards and comparison with ICP-MS determinations on seawater samples collected in the upper 1300 m of the subtropical south Indian Ocean. This work confirms that integration of sample pretreatment with optical detection in the LOV format offers a widely applicable approach to trace analysis of seawater

Assessment and monitoring of water quality of the gulf of Morbihan, a littoral ecosystem under high anthropic pressure

International audienceThis field study is intended to propose a global methodology to assess and monitor the water quality of the gulf of Morbihan, a littoral ecosystem under increasing anthropic pressure. To this end, the Locmariaquer site, where Crassostrea gigas is extensively cultivated, was selected to perform a one-year follow-up of tissular glutathione S-transferase and acetylcholinesterase specific activities in this filter feeder organism. Calculation of an integrated index, corresponding to the ratio of the two enzymes activities, allowed to discriminate from the environmental noise, several clusters which could be representative environmental stress, potentially latent pollution. Moreover, the estrogenic activity was assessed in water samples collected at Locmariaquer and other strategic sites of the gulf. The results evidenced a low estrogenic-disrupting compound contamination of waters. Overall, this methodology produced an accurate outlook of a basal state for the gulf and could be developed in the context of a chronic monitoring of this site

Difficulties in Differentiating Natural from Synthetic Alkaloids by Isotope Ratio Monitoring using (13) C Nuclear Magnetic Resonance Spectrometry

International audienceWithin the food and pharmaceutical industries, there is an increasing legislative requirement for the accurate labeling of the products origin. A key feature of this is to indicate whether the product is of natural or synthetic origin. With reference to this context, we have investigated three alkaloids commonly exploited for human use: nicotine, atropine, and caffeine. We have measured by (13) C nuclear magnetic resonance spectrometry the position-specific distribution of (13) C at natural abundance within several samples of each of these target molecules. This technique is well suited to distinguishing between origins, as the distribution of the (13) C isotope reflects the primary source of the carbon atoms and the process by which the molecule was (bio)synthesized. Our findings indicate that labeling can be misleading, especially in relation to a supplied compound being labeled as synthetic even though its (13) C profile indicates a natural origin