935 resultados para Recursos hídricos - Planejamento


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Indiscriminate and inappropriate use of pesticides in agriculture has been pointed out for increasing health problems and environmental damage. Considering that water resources are the principal destiny of those compounds after application, the present study presents optimization and validation of two simple and effi cient analytical methods for pesticides quantifi cation in both surface and groundwater. Were selected the pesticides more commonly used at Dourados (MS - Brazil), region with intense agricultural activity. Pesticides were preconcentrated by solid-phase extraction using C18 (500 mg) cartridges and then divided in two groups for elution and quantifi cation: 2.4-D and 2.4-DCP were eluted with methanol and quantifi ed by high performance liquid chromatography with ultra-violet detector (HPLC-UV) while atrazine, DIA, DEA, trifl uralin and methyl parathion were eluted with ethylacetate (1:1, v/v) and quantifi ed by gas chromatography with thermionic specifi c detector (GC-TSD). The methods showed satisfactory accuracy (76-107%) and precision (<12%) for the substances analyzed at the fortifi ed levels selected for the study, except for DIA (<51%). Study of pesticide stability also presented good results: C18 cartridges could be stored for at least for 21 days at -20ºC with no signs of the compounds degradability. Both methods limits of quantifi cation of the pesticides (0.22 - 0.48 μg L-1) are in accordance to the levels currently established by the Brazilian national legislation for pesticides in water. Although only the pesticide 2.4-D has been detected in two distinct collection points in the study period of time, this work warns for the requirement of systematical analysis of pesticides presence in water destined to human consume, principally in areas of intense agriculture activity. Such monitoring can provide subsidies for public environmental policies.

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Over the years, water has become an increasingly valuable resource and scarce, this situation is attributed to factors such as population growth, poor distribution and increasing degradation of water resources as a result of indiscriminate human activities in the middle environment, making their dwindling availability and increasing its cost. I n this context , the use of rainwater for non-potable purposes begins to be stimulated in Brazil , as a measure to preserve this resource , while in countries such as Japan and Germany , this technique has already been used for a long time. The ability to capture rainwater reduces the demand for sanitation companies, also resulting in cost reduction with the water bill and the risk of flooding in the event of heavy rains. The stored water is used only for non-potable purposes, such as toilets, taps into the garden, for washing vehicles and clothing. This work was developed with the aim of presenting the importance of rational use of water, associated with viability constructive economic and consumption of the installation of rain water harvesting, and for that, considered four case studies. From this study, it was found that the implementation of this system has led to a reduction in costs of water and sewer consumption poses no hazard to the user and its installation does not require significant changes in building construction, however, in relation to the economy, should be made a detailed analysis in each case for investment to bring a suitable financial return within the lifetime of the system