Toxic Effects of a Mixture of Pharmaceuticals in Mytilus Galloprovincialis: The Case of 17α-Ethinylestradiol and Salicylic Acid

Abstract

The impact of pharmaceuticals on marine invertebrates has been a topic of rising concern, with an increasing number of publications regarding the effects on bivalves. However, very few investigated the toxicity of mixtures of pharmaceuticals. This knowledge gap was addressed in the present study, where the toxicity of 17α-ethinylestradiol (EE2) and Salicylic acid (SA) mixture was evaluated. To this end, Mytilus galloprovincialis mussels were chronically exposed to both pharmaceuticals, acting alone and in combination, and the effects at the cellular level were measured. The integrated biomarker response (IBR) index was used to assess the overall biochemical response given by mussels. The results obtained clearly demonstrated that the most stressful condition was caused by the combined effect of EE2 and SA, with the highest metabolic capacity, antioxidant (catalase activity) and biotransformation (carboxylesterases activity) activation and cellular damage in organisms exposed to the mixture of both drugs in comparison to responses observed when each drug was acting alone. This study highlights the need for future studies considering the mixture of pollutants, mimicking the actual environmental conditions.

Keywords: Marine bivalves, metabolism, Oxidative stress, Integrated biomarker response