929 resultados para Águas subterrâneas - Contaminação


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Objective: To evaluate the microbial contamination in samples of radiographic developing and fixing solutions, radiographic processing water, dental unit waterlines and dental office's external water supply. Methods: Samples of 50 private dental offices and 20 dental offices of the School of Dentistry de Araçatuba-UNESP were collected. The samples were subjected to neutralization of the residual inhibitory agents followed by pre-enrichment in peptone water and EVA broth and were inoculated in selective and non-selective culture media. The DNA of the samples was extracted and the presence of superinfectant microorganisms was evaluated by PCR. The differences in the prevalence of the microorganisms in the samples of the solutions were analyzed by repeated-measures analysis of variance for category data, while the Chi-Square and Mann-Whitney tests were used to evaluate the existence of associations between the total number of heterotrophic microorganisms and infection control protocols. The significance level was set at 5%. Results: Samples of radiographic fixing solution presented a remarkably less frequent contamination than radiographic developing solution and radiographic processing water. The latter exhibited microorganisms typically originated from the oral microbiota and human skin as well as microorganisms frequently found in dental unit waterlines. There was less contamination of radiographic processing water in the dental offices where the x-ray film packets were disinfected before processing or were covered by a plastic film. Additionally, all samples of dental office's external water supply were drinkable. Conclusion: Covering the x-ray film packets with a plastic film protection barrier was proven the best manner to reduce the contamination of the evaluated solutions.

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In Brazil, due to the breeding season for Thoroughbred, the reproductive data are normally truncate, since the breeders try to get animals that were born at the beginning of the breeding season in order to take their competitive advantages (more developed, mature and trained animals) compared to animals born later in the same breeding season. To analyze these data suitable methods should be used. Then, this paper aims to compare three methodologies: the method of maximum restricted likelihood, using MTDFREML, bayesian analysis without censured data by software MTGSAM and bayesian analysis with censured data by software LMCD, to evaluate age at first conception in thoroughbred mares, in order to verify its impact on the choice of stallions during selection. The database contained 3509 records for age at first conception (months) for thoroughbred mares. The heritability estimates were 0.23, 0.30 and 0.0926 (log scale), for MTDF, MTGSAM and LMCD, respectively. Considering all animals in the pedigree (6713), ranking correlations varied from 0.91 to 0.99. When only stallions were considered (656), those varied from 0.48 to 0.99 (considering different percentages of selected males) between evalua-tion methods. The highest changes in the general classification were observed when LMCD was compared to the other two methods. As the linear censured model is the most suitable for trait analysis with censured data, it was observed that censure information would lead to the choice of different animals during the selection process, when compared to the two other methodologies.

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Coastal cities attract a large number of tourists for their beautiful landscape and recreational activities, increasing the municipalities' income source. Thus, a need is clear for the establishment of beach quality monitoring programs to ensure bathers health. Although there is an effective monitoring program for recreational waters in Brazil there are no programs to certify the quality of beach sands. In this sense, the aim of this work was to analyze the density of bacteria from the genus Enterococcus in both sand and water from two beaches from São Vicente, São Paulo (Brazil) and correlate these densities to abiotic parameters such as: temperature, salinity, particle size, organic matter and tides). Water and sand samples were collected during February 2006 on the beaches of Gonzaguinha e Ilha Porchat and bacterial densities were determined by membrane filter technique. Temperature and salinity were measured in situ with a thermometer and a refractometer while particle size and organic matter were determined according to methods described by Suguio and Dean. There were significant differences between densities found in water and sand (p=0.004), being approximately 20 times higher in Gonzaguinha's beach sands. Similar results were found for Ilha Porchat beach samples, being the densities found in sand 3 times greater than those found in water. Both beaches showed a negative correlation between bacterial densities and salinity and temperature, suggesting a deleterious effect of these parameters on the bacterial community. On the other hand, no correlation was found between organic matter and particle size and bacterial densities. This work demonstrates that there is a great necessity for monitoring beach sand since the evaluation of beach quality is an important part of integrated coastal management programs.

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The Ribeira de Iguape River basin received intense mining activities for lead exploiting and, as a result, the river received the discharges of estimated amounts of 5.5 tons/month of material rich in As, Ba, Cd, Pb, Cu, Cr and Zn. In this article, the toxicity of waters and sediments collected in Ribeira de Iguape River was assessed aiming to estimate environmental quality. Three sampling campaigns were conducted, from 2009 to 2010. Toxicity tests with the cladoceran Daphnia similis were done for water samples and for sediments, in this case using sediment-water interface exposure. Results showed in general absence of toxicity for sediments and waters, and only eventually were acute effects registered (marginal toxicity). Results are consistent with the conditions indicated by the literature, of low concentrations of metals in waters and sediments; however they differ from the monitoring made by the state environmental agency, which registered chronic toxicity. The occurrence of eventual acute toxicity indicates that although Ribeira de Iguape River quality is being restored, conditions still are not totally under control.

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The objective of this study was to evaluate the effect of supplemental protein during the rainy season on body growth, ingestive behavior and reproductive performance of crossbred Gir x Holstein dairy heifers, with mean age of 21 ± 4.1 months and average initial body weight of 296.7 ± 57.3 kg, distributed in a completely randomized design with four treatments and six replicates per treatment. Heifers remained on Brachiaria brizantha cv. Marandu pasture, managed according to a rotational grazing system and, as treatment, it was supplemented with protein concentrate (34%, 43%, 56% and 66% BW) and level of supply of 0.30% body weight (BW). The animals were weighed and the mean weight of the lot was used for the calculation of adjustment of the amount of concentrate offered. Heifers that reached 330.0 kg of live weight were artificially inseminated and, 45 days after insemination, pregnancy diagnosis was performed for the calculation of pregnancy rate and age at conception. No significant difference of protein levels was observed on grazing, eating behavior, productive performance and age at conception of dairy heifers on pasture. The average daily weight gain of BW and age at conception were, on average, 0.907 kg/animal and 24.03 months, respectively.

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Several factors have contributed to the increase the world production of urban solid waste, resulting in difficulties to the correct management and the final environmentally appropriate disposal, in addition to causing serious socio-economic, environmental, and public health troubles. The soil and groundwater contamination by leachate in waste disposal sites is almost always present, leveraging the emergence and/or adaptation of methodologies for environmental assessment of these areas. The geophysical methods, especially the electrical resistivity method, are fast, reliable and low-cost alternative for this purpose. This paper reports the methodology adopted for the temporal monitoring of the plume of contamination of controlled landfill in the municipality of Rio Claro (SP). Electrical resistivity data were obtained in 1999 and 2008, by the resistivity method, using the techniques of vertical electrical sounding and electrical profile. In both years, similar tests were carried out in the same locations within the disposal area. The results indicated that the plume of contamination has resistivity values less than or equal to 50 ohm.m and moves guided by 2 flows: the main, to the southeast, and the secondary, to the west. Relatively to the first series of tests in 1999, the plume of contamination was higher and deeper in 2008, contrary to what was expected for a landfill deactivated for at least 10 years.

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Several geothermometers have been employed to determine the expected temperature in the groundwater reservoirs, most part of them based on the chemical equilibrium between thermal groundwaters and minerals which constitute the aquifer framework. Based on this principle, groundwater from Guarani Aquifer System, which presents temperatures upon to 38°C, classified as hyperthermal by the Brazilian Mineral Water Code, had their chemical composition evaluated with the main purpose to determine the expected temperatures in the reservoir based on the application of several geothermometers. These groundwaters can be classified as Na-HCO3 type evolving to Na-HCO3-Cl-SO4 type due the increase in sulphate and chloride concentrations. Measured groundwater temperatures show a good correlation with the depth of the aquifer, indicating an average geothermal gradient of 27.7°C/km. The lowest geothermal gradients, bellow 25°C/km, are observed in the central portion of the study area; meanwhile the highest gradients are observed in NE and W portions of the study area. Quartz equilibrium based geothermometers return temperature over the measured temperatures, meanwhile chalcedony geothermometer returns temperatures near the measured in the wells, except for the wells located in the area which presents the lowest geothermal gradients. The geothermometers based on the equilibrium between Na/K have returned temperatures diverse from the measured at the field, meanwhile the geothermometer based on the equilibrium between Na/K/Ca has presented good match with groundwater which present temperatures under 50°C, due the thermodynamic equilibrium between these waters and feldspars. Geothermometers show evidences about mixtures between groundwaters from GAS and underlying units, especially in wells located in the SW portion of the study area.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Incluye Bibliografía

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Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC