Of these 2.5%, less than 1% are available for the humanity, since most of water candy meets in the form of ice, in calotas polar. The water-bearing ones are immense underground water reservoirs candy. They more than represent 90% of the water total candy eliminate existing in the planet. From there the water-bearing ones to play a basic role in the public and private supplying of water in the whole world, satisfying the necessity of approximately 1,5 billion of people. The world-wide trends show a strong growth of these ciphers, mainly in countries of peripheral economies (dependents of the economy of richer countries), that its easy attainment and good natural quality find in the underground water an alternative of low cost due. The underground water presents excellent quality generally, being proper for the human consumption, many times same without previous treatment.
But also the underground waters can be contaminated by activities diverse human beings. The systems of sanitary exhaustion (fossas, septic, latrines), the deposition in the ground of certain residues of origin domesticates or industrial and the inadequate agricultural fertilizer use is examples of sources of contamination of water-bearing, can be reached by microorganism transmitting of illnesses, nitrogenados composite excess, metals heavy and other agent comprometedores of the quality of the water. Therefore, the study of the water-bearing ones aiming at the exploration and the protection of the underground water it constitutes one of the objectives more importantesda hidrogeologia. MasterClass takes a slightly different approach. The biggest water reserve candy of the South America is the water-bearing Guarani, that occupies about 1,2 million of km and is extended for Brazil, Paraguay, Uruguay and Argentina. Most of this water-bearing one, still little explored, is in Brazil, an area of approximately 840 a thousand km, enclosing the states of Gois, Minas Gerais, Mato Grosso of the South, So Paulo, Paran, Santa Catarina and Rio Grande Do Sul.