Francisco de Assis Matos de Abreu

Águas subterrâneas em Rondônia: análise estatística de dados hidroquímicos, organolépticos e bacteriológicos

In order to improve the ongoing process of managing groundwaters in the State of Rondonia we collected the results of 384 physical-chemical and / or bacteriological analyses of wells on file in the 2nd Socio-Economic and Ecological Zonation of the State of Rondonia, Brazil - ZSEE / RO, submitted by localities. We then treated and reorganized these data according to hydrographic basins using spreadsheets. We sought to characterize the quality of groundwater in major watersheds of the state of Rondonia by considering physical (color, pH and turbidity), chemical (chloride, total iron, sulfate, oxygen consumption, total hardness, calcium hardness, magnesium hardness, total solids, nitrogen as nitrite, nitrogen as nitrate, free carbon dioxide and HCO3 alkalinity) and bacteriological (standard bacterial counts of most probable number of coliform bacteria, most probable number of fecal coliform bacterial, most probable number of colonies - membrane filter method) properties. In order to test the adjustment of the data obtained to a normal distribution, we used the Kolmogorov-Smirnov method, modified by Lilliefors. The study revealed that the groundwater analyzed had good physical-organoleptic properties; the basins of the Madeira and of the Machado rivers showed the greatest changes in pH values, chloride and nitrate, indicative of a loss of quality of groundwater resources depending on population density. The Abunan river basin revealed the highest risk of fecal contamination, with water samples generally showing results that exceeded the bacteriological standards, thus requiring treatment by chlorination or boiling and filtration before human consumption.

Evolução geológica das sequências do embasamento do Cinturão Araguaia na região de Paraíso do Tocantins (TO), Brasil

Isotopic studies based on single zircon Pb-evaporation and Sm/Nd (whole rock) methodologies, allowed advances at the lithostratigraphic scene and geologic evolution of basement, in the south segment of Araguaia Belt. The identified geological processes took place from the Achaean (2.6 Ga and T DM ages varying between 2.78 and 3.25 Ga) through Neoproterozoic Era. The Paleoproterozoic ortognaisses, represented by Rio dos Mangues Complex, are placed between 2.05 and 2.08 Ga, and they were formed from a mantellic and youthful source, with a small crustal contribution where T DM ages are 2.35 e 2.21 Ga. At the end of the Paleoproterozoic, a strong crustal shortening happened, and a partial melting of isolated and thickening compartments were facilitated, generating some igneous bodies (1.85 and 1.82 Ga) and Serrote Granite (1.86 Ga), that comes from sources situated between 2.50 and 2.43 Ga. At the end of the Mesoproterozoic, the region was marked by taphrogenetic processes, evidenced by the appearance of alkaline magmatism (1.05 Ga), beyond depositional basins, amongst which the one that received the sediments that had originated the supracrustals of Araguaia Belt. Through the inversion in the geodynamic conditions, in the Neoproterozoic, a process of horizontal shortening with crustal thickening and distinct volumetric and spatial melting occurred, which may have generated Matanca and Santa Luzia Granites. The Araguaia Belt was built from this tectonic motion. The tectonic mass transport in the Amazonian Craton might have occurred, resulting in the current architecture in the form of imbricate fans.

Caracterização da Qualidade de Águas Superficiais em Rondônia

In order to contribute and improve the process of water management in progress in Rondonia, the results of physico-chemical and bacteriological waters from rivers, samples collected at 64 points, on file with the second Socioeconomic-Ecological of the Rondonia State - 2nd ZSEE / RO, presented by river or creek and municipality, were treated and rearranged by basin, through the use of spreadsheet “Excelg and Statistica software. It sought to characterize the quality of surface water in major river basins in the State of Rondonia, considering physical and organoleptic properties, chemical and bacteriological. It has also been made and assessing the potability of water quality index - IQA. With the analyzes were obtained descriptive information, and to test the fit of the data to the normal distribution, it used the method of Shapiro-Wilk. The study concluded that surface water generally analyzed exceeded the bacteriological standards of potability, requiring treatment by chlorination or boiling and filtration prior to human consumption.