Microbiological and Toxicological Assessment of Pharmaceutical Wastewater from the Lagos Megacity, Nigeria

We conducted a microbiological and toxicological profiling of a pharmaceutical wastewater, one of the major wastes entering the Lagos lagoon. The morphological characterization of seven bacterial isolates from the wastewater indicated that 4 of them were gram positive bacilli while 3 were cocci of both gram reactions. The bacterial isolates exhibited varying degrees of enzyme activities but most were able to hydrolyze starch to yield amylase. Only 3 of the isolates showed prospects as antibacterial agents, given their moderate inhibition toStaphylococcus xylosusrelative to 8 other species tested. Overall, 81.3% of the isolates were resistant, and 3.3% were susceptible while 15.4% of the isolates showed intermediate sensitivity to the antibiotics. The assessment of antioxidant activities in liver samples ofNile tilapia,Oreochromis niloticus, exposed to sublethal concentrations of the effluents indicated some form of oxidative stress given the higher levels of lipid peroxidation product, malondialdehyde, in the exposed fishes relative to the control kept in dechlorinate tap water. But for reduced glutathione, activities of the antioxidative stress enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST), were higher in the effluent exposed tilapia. Responses were not dose dependent and enzyme activities were often higher at day 14 compared to day 28. This relevance of the findings to water quality was discussed.