Effects of single and combined exposure to cocaine and benzoylecgonine on the oxidative status of Mytilus galloprovincialis.

The information concerning the effects of single and combined exposure to cocaine (COC) and its main metabolite, the benzoylecgonine (BE), towards marine organisms is still scant. Thus, the aim of this work was to compare the effects induced by 96 -hs exposure to a concentration of COC (500 ng/L) or BE (20 ng/L) and their mixture (500 ng/L of COC and 20 ng/L of BE) on Mytilus galloprovincialis. Oxidative stress biomarkers were applied on mussel gills and digestive gland, investigating changes in the amount of reactive oxygen species, activity of antioxidant (SOD, CAT and GPx) and detoxifying (GST) enzymes and lipid peroxidation. Independent exposure to COC and BE slightly altered mussel oxidative status in both the organs, while the mixture induced more marked responses compared to single molecules. Our results suggest the necessity to explore the toxicity of illicit drug mixtures to shed light on the risk of these molecules to marine organisms.