Hidrogeología del Brasil: una breve crónica de la potencialidades, problemática y perspectivas
2006; Spanish Geological Survey; Volume: 117; Issue: 1 Linguagem: Espanhol
ISSN
2253-6167
AutoresJosé Luiz Gomes Zoby, Reginaldo Antônio Bertolo, Amélia João Fernandes, R. Hirata,
Tópico(s)Geography and Environmental Studies
ResumoespanolBrasil siempre ha vivido una gran contradiccion en relacion con el recurso hidrico. Es el pais con mayor abundancia hidrica del planeta (12% o 179.374 m3/s y una disponibilidad de 33.000 m3/hab/ano), resultado de una precipitacion media de 1.797 mm/ano en una superficie de 8,52 millones de km2; sin embargo, enfrenta serios problemas por falta de agua, debido a la demanda excesiva en areas urbanizadas y a la falta de inversion en infraestructura en regiones pobres. La recarga media de los acuiferos es de 42.289 m3/s y estos abastecen al 30 a 40% de la poblacion brasilena, a traves de 400.000 sondeos y centenares de miles de pozos excavados. Dada la gran extension del pais, existen grandes unidades acuiferas distribuidas en diversas cuencas sedimentarias y en los escudos cristalinos. La calidad de las aguas subterraneas es generalmente buena y apta para consumo, con problemas localizados de fluor (Sistema Acuifero Guarani y Serra Geral), cromo (noroeste del Sistema Acuifero Bauru), hierro y manganeso (en unidades sedimentarias cenozoicas) y salinidad (semiarido de la Region Noreste). La contaminacion antropica esta presente en los grandes centros urbanos, a pesar de que falten estudios sistematicos para una evaluacion mas precisa. El nitrato es el contaminante mas comun, asociado a las actividades agricolas y a la falta de red publica de alcantarillado. Otros contaminantes importantes son: combustibles liquidos de petroleo, solventes aromaticos, PAHs, metales pesados y solventes halogenados, asociados a las estaciones de servicio, rellenos sanitarios, basureros a cielo abierto e industrias. EnglishAlthough Brazil has the largest amount of water resources in the world (12% or 179374 m3/s and an availability of 33000 m3/inhab/y), which results of a precipitation averages of 1707 mm/y in an area of 8.52 million km2, this country faces serious problems of lack of water. This is due to: great demands in very large urban areas, low infra-structure investments on poor regions, and the concentration of the water resources is heterogeneous and does not accompany the concentration of population. The average for aquifer recharge is 42289 m3/s and this supply water to 30-40% of the Brazilian population, by means of 400000 boreholes and thousands of hundreds of dug wells. There is a great amount of aquifer units distributed in the sedimentary basins and Precambrian basement that occupy the great extension of Brazil territory. The water quality is usually good and suitable for drinking. Concentrations above the potable standards for some elements, such as fluorite (Guarani Aquifer System), chromium (northwest portion of Bauru Aquifer System), iron and manganese (Cenozoic Aquifers) occur at the local scale. Salinity is a common problem of the Northeast Region where dry climates predominate. Anthropogenic originated contamination of nitrate, due to the lack of septic systems, seems to be most common in large urban centers; however systematic investigations are necessary in order to evaluate its extension. Agricultural activities are also a common source of nitrate contaminations. Besides, other significant contaminants are: oil liquid fuels, aromatic solvents, PAHs, heavy metals and halogenated solvents, being derived from gas stations, waste disposal facilities, and industries.
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