Ferrite-dependent oxidative and histopathological responses in Mytilus galloprovincialis exposed to post-treatment acesulfame media.

Acesulfame (ACE) is an artificial sweetener frequently detected in aquatic environments and increasingly targeted by advanced oxidation processes. However, the biological consequences of exposure to treated media remain poorly understood. This study evaluated oxidative stress biomarkers and histopathological alterations in the Mediterranean mussel Mytilus galloprovincialis after 96 h exposure to ACE media treated using Fe₃O₄ and ZnFe₂O₄ nanoparticles under natural light conditions. Superoxide dismutase, catalase, glutathione S-transferase, malondialdehyde and histopathological alterations were evaluated in gill and digestive gland tissues. Both treated exposure media induced significant biochemical and histopathological responses. Antioxidant biomarkers varied according to nanoparticle type, tissue and exposure concentration, whereas lipid peroxidation and tissue damage increased with increasing nominal exposure concentration, with more pronounced responses observed in several ZnFe₂O₄ treatment groups. These findings highlight the importance of complementing conventional assessments of treatment performance with ecotoxicological endpoints when evaluating treated exposure media.