Abstract

The concentrations of some heavy metals in the effluents of nine pharmaceutical companies operating in Lagos, Nigeria were determined using atomic absorption spectrophotometer. The heavy metals analyzed in this study included Cadmium, Chromium, Lead, Nickel, Zinc and Copper. Most of the samples were found to contain the metals in varying concentrations. The highest concentration of heavy metal detected was Zinc with concentration of 1.437 mg/L. Mostly, the concentrations were above the WHO recommended maximum contaminant concentration level. The highest concentrations were found to be 0.132 mg/L for Nickel, 0.644 mg/L for Lead, 0.337 mg/L for Copper, 0.280 mg/L for Cadmium, 1.437 mg/L for Zinc, and 0.491 mg/L for Chromium. This study reveals the need for enforcing adequate effluent treatment methods before their discharge to surface water to reduce their potential environmental hazards.

Key words: Heavy metals, pharmaceutical effluents, ecotoxicity, surface water.