Correlações entre íons e a salinidade de águas subterrâneas e superficiais, visando a irrigação, no Sertão de Pernambuco.

Abstract

The objevtive of the study was to determine the relation between the electrical conductivity of subsurface and surface water (C.Ea in dS/m at 25°C) and the ions concentratíon of Na+, Ca+2, + Mg+2 and Cl- (in meq/l). The datas were estimad from 74 and 100 samples collected from subsurface and surface water, respectively, in 33 counties in the semiarid of Pernambuco. Results showed higher accuracy for Na+, Ca+2 + Mg+2 and Cl- through the single linear regression equation, Y = a + b x, as described below:

a) Subsurface water Y (Na+) = - 0,385 + 4,758 (C.Ea); r = 0,95 Y (Ca+2 + Mg+2) = 0,319 + 4,758 (C.Ea); r = 0,93 Y (Cl-) = 1,755 + 3,525 (C.Ea); r = 0,74 b) Surface water Y (Na+) = - 0,672 + 5,070 (C.Ea): r = 0,97 Y (Ca+2 + Mg+2) = 0,972 + 3,222 (C.Ea); r = 0,88 Y (Cl-) = - 0,976 + 6,971 (C.Ea); r = 0,98