Naproxen-Enriched Artificial Sediment Induces Oxidative Stress and Genotoxicity in Hyalella azteca

The nonsteroidal anti-inflammatory naproxen sodium is among the most commonly used pharmaceuticals in Mexico. Nevertheless, there is no adequate regulation to control its sale, use, and disposal. This agent can enter water bodies by diverse pathways, attaining significant concentrations, especially in sediments since they are the final reservoir of many organic contaminants, and may induce damage on hydrobionts. Naproxen sodium is water-soluble, shows stability in aquatic ecosystems, and can form reactive products when oxidized. The aim of this study was to evaluate the oxidative stress and consequent damage to genetic material induced by naproxen sodium in sediments on Hyalella azteca. After 48 h of exposure to artificial sediments enriched with 76.6 and 339.2 mg kg^-1 (equivalent to 1/10 of the LC₅₀ and the NOAEL obtained in an earlier 48-h acute toxicity assay), the following biomarkers were evaluated: lipid peroxidation level, protein carbonyl content, activity of the antioxidant enzymes, and DNA damage. Results show that naproxen sodium induces oxidative stress (increased lipid and protein oxidation, as well as superoxide dismutase and catalase activity and decrease of glutathione peroxidase activity) and genotoxicity (increased oxidative damage of DNA) at sublethal concentrations on H. azteca, being the damage, concentration dependent.