Composição Química De Águas Do Cristalino Do Nordeste Brasileiro

Abstract

RESUMOObjetivando-se determinar a variação da composição iônica de águas do cristalino do Nordeste brasileiro, realizou-se este trabalho utilizando-se um banco de dados correspondente a 557 resultados de análises químicas de água de diversas fontes, com condutividade elétrica (CEa) até 5.000 µS cm ABSTRACTThe objective of present study was to evaluate variation of ionic composition of water from cristalline region of the northeast Brazil, utilising data bank of 557 results of chemical analysis, with electrical conductivity up to 5,000 µS cm -1 , belonging to different rural farms, in the states of Paraiba, Rio Grande do Norte and Ceara. The chemical composition of water in terms of percentage, lithology of place of origin and water salinity level was evaluated. The study was made with graphs and regression analysis between salinity and contents of Cl -, Na + , Ca 2+ + Mg 2+ and SAR. The results show that in general, the water from cristalline Brazilian northeast has lot of sodium chloride and it varies with the lithology place and for prediction purposes regression equations based on local data perform ed better than global equation except for Ca 2+ + Mg 2+ for nucleus of Pau dos Ferros-RN.

Salinization mechanisms of a small alluvial aquifer in the semiarid region of northeast Brazil

“…Other studies on salinization of groundwaters by evaporation (Schoeller, 1959;Cruz & Melo, 1968;Silva Júnior et al, 1999;Lopes, 2008) corroborate these results, which are consistent with the study of Robaux (1953) for arid zones, who found that direct evaporation acts up to 2 m deep, but considers that it can reach 22 m in alluvial soils, through the influence of capillarity, promoting a progressive salt concentration.…”

“…Water with high salt concentration is usually found in areas of crystalline rock formation (Silva Júnior et al, 1999;Lopes et al, 2008), while water with low salt concentration is found in areas of sedimentary rocks (Andrade Júnior et al, 2006;Silva et al, 2007).…”

Similaridade da qualidade das águas superficiais da bacia do Curu, Ceará

“…Esse comportamento de diluição dos sais no período chuvoso é comum nas regiões semiáridas, pois as águas das chuvas possuem uma concentração salina de CE 0,05d Sm -1 . Os principais elementos responsáveis por essa tendência na região semiárida são os Na + , Cl - (SILVA JÚNIOR et al, 1999 3-e SO 4 -, são maiores no grupo 4, que corresponde ao período chuvoso, época em que a chuva, ao promover a lavagem dos solos, carreia para os corpos hídricos os elementos provenientes da atividade humana. Uma outra possível fonte para esses íons estarem presentes são os adubos aplicados nos perímetros irrigados, que utilizam principalmente uréia, nitrato de potássio, cloreto de potássio e superfosfato como fonte de macro nutrientes para culturas como coco e banana (D'ALMEIDA et al, 2005).…”

Emergence, growth, and flowering of castor beans as a function of the cationic composition of irrigation water

“…Further, water sources with high salt concentrations are quite common (SILVA et al, 2005;BEZERRA et al, 2010). Silva Júnior et al (1999 evaluated the variation in the ionic composition of water from the crystalline region in the Northeast of Brazil (the states of Paraíba, Rio Grande do Norte, and Ceará) and observed a predominance of sodium-chloride water with certain variation regardless of the salinity level, site, or source.…”