AN INTEGRATED APPROACH TO GROUNDWATER QUALITY ASSESSMENT IN DETERMINING FACTORS THAT INFLUENCE THE GEOCHEMISTRY AND ORIGIN OF SANDSTONE AQUIFER SOUTHERN NIGER DELTA REGION OF NIGERIA

Rapid industrialization and oil exploration activities are believed to have influence on groundwater quality globally, and Niger Delta Region of Nigeria is no exception. Hence, this research is conducted to evaluate factors that affect groundwater origin and its geochemistry. For the purpose of this study, 20 groundwater samples were collected (4 from borehole and 16 from hand-dug wells). The parameters used in the assessment include physical parameters; pH, total dissolved solid and electrical conductivity and chemical parameters such as; major cations and anions. From the findings it was observed that pH values fell within the slightly acidic range with the exception of sample location HG/08 with value of 7.01 which can be considered as neutral. The dominant factors that influence groundwater origin and geochemistry within the study area are mainly precipitatio n and weathering. From Gibb’s plot ninety percent (90 %) of groundwater chemistry is influenced by precipitation. Soltan classification showed that 98 % of groundwater belongs to (Na + – SO 42¯ ), hence it can be classified as deep meteoric (precipitation influenced), while the remaining two percent (2%) is of (Na + - HCO 3¯ ) and can be classified as shallow meteoric type. Lastly from relationship between Cl¯/HCO 3 ¯ groundwater was slightly moderately affected by saline water intrusion.