Abstract

Nwanebu F. C.1 *, Ogbulie, J. N.1 , Obi R. K.1 and Ojiako O. A.2

Partially eutrophicated site (A) and free-flowing site (B) of Otamiri River in Owerri, Nigeria, separated by a barricade were evaluated to determine their relative pollution status. Microbiological analysis using membrance-filtration techniques detected high presence of Salmonella spp., Vibro spp., Staphylococus aureus and faecal Streptococci. Aerobic bacterial counts of 5.0 x 105 cfu/100ml were obtained from site B and 4.5x 103 cfu/100ml from site A. The physico-chemical analysis revealed high conductivity of 178 umhoo/cm with total dissolved solids (TDS) of 89.0 mg/L at site B and 52 umhoo/cm with TDS of 26mg/L at site A. Recovery of PO43- , SO4 2- , N03- , was obtained, though more at site A than Site B, indicating pollution. Statistical analysis revealed significant differences (P<0.05) in pollution indices obtained between sites A and B. The barricade encouraged siltation and nutrient accumulation at site A creating an eutrophic environment that further complicated a desperate pollution status of the river due to indiscriminate dumping of refuse. This river serves as drinking water source to many inhabitants of Owerri municipality with villages beyond. Government effort to protect it from over pollution is therfore highly desired.