Physicochemical, microbiological and heavy metal studies on water samples and bacteria obtained from Dandaru River in Ibadan, South-western Nigeri

The physicochemical, microbiological and heavy metal studies of water samples and bacteria obtained from the Dandaru River were investigated. Water samples were collected from six different sampling points along the course of the river and analysed using standard procedures. The physicochemical parameters showed that the water samples at point 5 had the highest value for all the parameters except Total Dissolved Solids. The heavy metal analysis revealed that the mean concentration of zinc, lead, chromium and iron were highest at point 5; 2.11, 0.02, 0.04 and 0.54 mg/l respectively, while that of copper and manganese concentration was highest at point 4 (0.59 and 0.41 mg/l respectively). The total heterotrophic bacteria count was between 3.6 - 64.0 ×101 cfu/ml, with point 3 having the least value (3.6×101 cfu/ml); while the coliform count using Most Probable Number (MPN) tube method ranged from 350 - ≥1600 MPN index/100 ml. The bacteria obtained belonged to the genera Bacillus, Enterobacter, Escherichia, Pseudomonas and Staphylococcus. On exposure to increasing concentration of six heavy metals, 47.62% of the total bacteria obtained were observed to be growing at 500 µg/ml for all the six metals employed in this study, while the others showed varying degree of tolerance to the metals. Key words: Heavy metals, physicochemical, microbiological, river, bacteria.