HYDROGEOCHEMICAL ASSESSMENT OF CHEMICAL COMPOSITION OF GROUNDWATER; A CASE STUDY OF THE APTIAN-ALBIAN AQUIFER WITHIN SEDIMENTARY BASIN (NIGERIA)

: The research was carried out to evaluate major source influencing chemical quality of groundwater within suburban area of Abakaliki. It lies between latitudes 6°15' and 6°35'N and longitudes 7°40' and 8°15'E. A total of twenty one (21) groundwater samples were collected and analyzed. Parameter analyzed were; EC, pH, TDS, Cl¯, Na , Mg , NO ¯, SO ¯, Ca , HCO ¯, K , CO ¯ these parameterwere analyzed using American Public + 3 Health Association standard method. Various hydrogeochemical approach and model were used to assess chemical quality of groundwater within the study area. These include; Gibbs, Mg /Ca . End-member, Diamond 2+ 2+ field of Piper and Parson plots were used to indentify major source influencing groundwater chemistry within the study. Finding, from Gibbs plot and Mg /Ca against Mg /Na revealed that rock dominance is the major 2+ 2+ 2+ + process that control groundwater chemistry, while End-member plot showed that silicate and carbonate weathering are the two weathering process that influence groundwater chemistry within the study area. Diamond field of Piper by Lawrence and Bal-Subramanian modified, revealed that groundwater fell within High Ca + Mg & SO + Cl. Parson plot revealed that 65 % of groundwater fell within Ca - Mg – Cl water type, while 4 35 % fells within Ca - Mg - SO . Relationship between TDS vs TH plots showed that groundwater samples fell 4 within soft - fresh water category. The results of the geochemical survey reveal major ionic components trend in other of Mg>Ca>Na>HCO3>SO4>Cl, result reveal that there is no particular trend of ions movement in groundwater.