Origin of saline groundwater in parts of the Middle Benue Trough, Nigeria

Abstract

Determining the origin of saline groundwater is crucial for effective water resource man
agement and protection, and to obtain clues for minerals and petroleum discoveries. Out 
of groundwater that were sampled and analyzed from part of the Middle Benue Trough, 3 
are saline water that are discharged from folded and faulted sandstone of the study areas. 
Inductively coupled plasma mass spectrophotometer was used to analyze the major cat
ions and trace elements while titration was used to analyze for sulphates ion chromatographic method. Oxygen isotopes (δ18O) in water samples were analyzed via 
COequilibration, and hydrogen isotopes (δ2H) in water samples were analyzed by ther
mochemical reduction method. Three different statistical analyses—Piper trilinear dia
gram and Chadha plot, Cl/Br ratio, and isotopes plot—were used to determine the origin 
of groundwater in the study area. Using Piper trilinear diagram and Chadha’s plot, Cl/Br 
ratio, and isotope plot, three origins were discovered as meteoric, mixed, and marine. All 
the saline water in the study area are marine in origin and are associated with sandstone 
aquifers found in the Asu River Group and Awe Formations which are the oldest formations in the study area. In Nigeria, there is no work done on the use of Chadha’s plot and 
Cl/Br ratios to determine the origin of saline groundwater