Behavioral, physiological and biochemical responses and differential gene expression in Mytilus galloprovincialis exposed to 17 alpha-ethinylestradiol and sodium lauryl sulfate

Mixture of contaminants often determine biological responses of marine species, making difficult the interpretation of toxicological data. The pharmaceutical 17 alpha-ethinylestradiol (EE2) and the surfactant Sodium Lauryl Sulfate (SLS) commonly co-occur in the marine environment. This study evaluated the effects of EE2 (125.0 ng/L) and SLS (4 mg/L), acting individually and combined, in the mussel Mytilus galloprovincialis. Contaminated mussels closed their valves for longer periods than control ones, especially in the presence of both contaminants, with longer closure periods immediately after spiking compared to values obtained one day after spiking. Nevertheless, males and females increased their metabolism when in the presence of both contaminants (males) and SLS (females), and independently on the treatment males and females were able to activate their antioxidant and biotransformation defences. Although enhancing defences mussels still presented cellular damage and loss of redox balance, especially noticed in the presence of EE2 for males and SLS for females. Histopathological damage was found at mussel's gills in single and mixture exposure, and qPCR analysis revealed a clear estrogen receptor expression with no additive effect due to combined stressors. The results obtained highlight the harmful capacity of both contaminants but further research on this matter is needed, namely considering different climate change scenarios.

Automated summary

Mixture of contaminants, such as 17 alpha-ethinylestradiol (EE2) and Sodium Lauryl Sulfate (SLS), have harmful effects on the mussel Mytilus galloprovincialis. The contaminated mussels showed increased closure periods and metabolic activity, as well as activation of antioxidant and biotransformation defenses. However, they also experienced cellular damage and loss of redox balance, particularly in the presence of EE2 and SLS. Histopathological damage was observed in the gills of the mussels, and there was clear estrogen receptor expression. Further research is needed to understand the impacts of these contaminants in different climate change scenarios.