Ameh E. G and Akpah, F.A
A total of thirteen (13) surface water samples collected during dry and onset of rain seasons were analysed for some variables. Data collected in both seasons were subjected to heavy metal pollution indexing (HPI) and metal index (MI) approaches in conjunction with multivariate statistical technique. Significant variations were observed between the seasons. The HPI calculated for both seasons are 1408.33 and 299.32 respectively. These are far above the critical index value of 100, indicating pollution with respect to heavy metals. MI index based on total trend evaluation of the river status was 403 and 87.12 respectively, clearly indicating low-quality water. MI > 1 is a threshold of warning. Five factors chosen for interpretation accounts for 95.20% of total variance in the data set. The first factor is an association of pH, Tds, Ec, alkalinity and K while the second factor is characterized by temperature, K, SO4, Fe and Ni. The third and fourth factors are made up of Cl, NO3, Pb and temperature, Cd respectively. The fifth factor is characterized by Cu only. R-mode cluster produces four and Q-mode cluster three major groupings respectively with the highest similarity existing among cluster one in each mode. This shows that hydrogeochemical constituents of the water are mainly controlled by Tds, Ec, K, SO4, NO3 and Cl. This study reveals the need for heavy metal indexing and statistical approaches in hydrogeochemistry.
