Multibiomarker assessment of the ecotoxic effects of naproxen in African fresh water catfish ( <i>Clarias gariepinus</i> ) juveniles

Pharmaceutical contamination of the aquatic ecosystem has become an emerging challenge because of their impact on non-target aquatic organism. The sub lethal effect of naproxen-a non-steroid anti-inflammatory drug was studied for 28 days in a semi-static bioassay system on the African fresh water catfish (<i>Clarias gariepinus</i>). Acute toxicity study was carried out to determine the median lethal concentration (LC₅₀) of the pharmaceutical. After the LC₅₀, of the drug was determined, the fish was exposed to 0.0 mg/L (control) and the different sub-lethal concentrations of naproxen (3.46, 2.31 and 1.73 mg/L which are 1/10th, 1/15th, and 1/20th of the LC₅₀ of naproxen, respectively). The fish blood, brain, liver and gill were assessed to study the effects of the drug on haematological, biochemical, oxidative stress and neurotoxic parameters in the fish. The fish was exposed to the drug for 21 days followed by depuration for 7 days. The study revealed significant reduction (<i>p</i> < 0.05) in the activities of superoxide dismutase, catalase and total protein levels in a dose dependent manner while neutrophil counts, lipid peroxidation, acetylcholinesterase, gluthathione reductase and gluthathione peroxidase significantly increased (<i>p</i> < 0.05) in a dose and duration dependent manner in the groups exposed to naproxen. The liver enzymes such as alanine aminotransferase, aspartate aminotransfearase and alkaline phosphatase showed a significantly increased level in all the groups exposed to naproxen. The observations from this study revealed that naproxen is toxic to <i>Clarias gariepinus</i> juveniles by the evidenced negative impact on the parameters studied and should, therefore, be closely monitored in the aquatic environment.