GEOCHEMICAL AND STRUCTURAL COMBINATIONS IN THE ASSESSMENT OF UNDER-GROUNDWATER QUALITIES OF SOME EMERGING SETTLEMENTS IN IBADAN, SOUTHWESTERN NIGERIA.

Efforts to monitor groundwater qualities in conjunction with its interaction with rocks and minerals are still in continuous process. The role of joints and fractures in the natural filtration process which aid the enhancement of underground water quality need to be examined. Therefore, the sub-surface structures together with the anisotropic properties of fractures and direction of underground water flow in the bedrock of four (4) emerging communities within Ibadan metropolis was investigated. One hundred and fifty seven (157) groundwater samples were collected, analyzed geochemically using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) while square array method was adopted for investigating the structures. The pH values in the study area vary from 6.65-7.90 suggesting near neutral to alkaline nature of the water. The electrical conductivity (EC) vary from 107 μscm^-1 to 551 μscm^-1 this falls between the permissible level of World Health Organization. Higher carbonates-432 mgl^-1 values than the WHO-340 mgl^-1 standard indicate water hardness derived from carbonates mineral in the migmatite/gneissic rock. Total hardness a common property in Ibadan waters signifies water that is hard in terms of soap consumption and harsh in taste. The highest observed concentration for the TH is 563 mgl^{- 1} which is above desirable limit (119 mgl^-1) of WHO-2004 for total hardness. Fractures orientation correlated adequately with the measurements of joints and fractures obtained during mapping exercise. These directions might have a connection to the direction of underground water flow it may also increase the vulnerability influence of the water to CO₃^2- and hardness. In conclusion, a reasonable hygienic culture and cleaning management should be imbibed in order to ensure safer water devoid of leachates that can be conducted through fractures into groundwater systems. [ABSTRACT FROM AUTHOR]