Chemometric Assessment of Orashi River after Confluence with Oguta Lake

This study was carried out to evaluate the surficial water and sediment of Orashi River after confluence with Oguta. A total of 50 sub-samples were collected for the two media and were homogenized to form 10 composite samples (5 each). Water and sediment samples were analyzed for heavy metals concentrations and physico-chemical parameters. Data obtained was interpreted using ten chemometric models and standards of the Federal Ministry of Environment as touchstone values. Approximately 100 % of water samples were contaminated as opposed to 40 % of sediment samples. Both water and sediments showed that Cd as the highest contaminant with contamination factors of 38 and 1.52 respectively. Water revealed pollution load index higher than sediment probably due to its dissolution ability to metals. Geo accumulation index was observed to have highest value for Cd (45) at point A while Fe (> 4) at all points and same time the highest negative value. All points exhibited very high ecological risk (RI; 1112.7–1473.9) for water while sediments at those points showed low (RI Cd>Ag>Cr>Fe>Cu>Mn>Co>Ni. In conclusion, the water was polluted but good for irrigation use. However, continuous use could lead to health problems due to bioaccumulation of metals while sediments were generally not polluted and of good qualit