ORIGINAL ABSTRACT

Glyphosate (GLY), one of the most widely used herbicides, and its main breakdown product aminomethylphosphonic acid (AMPA), are frequently detected in aquatic environments. Despite GLY toxicological relevance and environmental implications remain debated, its use was recently renewed in the EU until 2033. This study assessed sublethal effects of single and combined exposures to GLY and AMPA at an environmentally realistic concentration (0.5 µg/L) in Mytilus galloprovincialis. A broad panel of cellular alterations related to immune and cholinergic function, DNA integrity, as well as xenobiotics, oxyradical, peroxisomal and lipid metabolism was evaluated after 28 days of exposure and 14 days of recovery. Results were elaborated through weighted criteria to provide hazard classification based on magnitude and toxicological relevance of observations. Such elaboration provided a higher cellular hazard for AMPA (alone or in mixture) compared to GLY, based on harsher lipid dysregulation, immuno-, neuro- and genotoxic effects. The hazard classification remained unchanged after the recovery phase, due to a limited capability of repairing cellular unbalance in AMPA-exposed organisms and delayed onset of neurotoxicity in GLY-exposed mussels. Overall, the obtained results highlight the urgent need to consider the inclusion of AMPA and GLY, in environmental monitoring and regulatory frameworks for aquatic ecosystems.