ASSESSMENT OF THE DISTRIBUTION OF HEAVY METALS IN BONNY RIVER, NIGERIA

ABSTRACT

The study investigated heavy metal levels in the Bonny River. Water and sediment samples, collected at four major sites selected along the river course, were analyzed for heavy metals (Pb, Zn, Ni, Cd, Cu, and As) using standard methods. The pH in water was higher (7.94) than in sediment and EPA standards (6.5-7.5) and in water; it was lower than the recommended values for EPA and WHO. Descriptive statistics and Pearson correlation were used to analyze data at PAs>Cu>Pb>Cr>Cd>Ni. In sediments, values were low (0.08-023mg/kg for Pb, 0.22-0.53mg/kg for Zn, 0.01-0.041mg/kg for Ni, 0.022-0.084mg/kg for Cd, 0.095-0.215mg/kg for Cr, 0.023-0.32mg/kg for Cu and 0.03-0.086mg/kg for As and in relative order of As>Zn>Pb>Cu>Cr>Cd>Ni. Significant positive correlation at P>0.05 was observed between heavy metals in water and sediment, Ni & As (+0.925**), Cd & Cr (+0.787*), Ni & Cu (+0.729*), Cu & As (+0.710*). Heavy metal pollution index for water ahead a maximum value (0.67) at downstream location and was below the critical index value of 100. Contamination factor (CF) for sediment revealed that heavy metals shoed low (CF