Transgenerational effects of environmentally relevant concentrations of ibuprofen on Daphnia magna.

The widespread occurrence of ibuprofen in aquatic environments poses potential risks to aquatic organisms. This investigation employed a multigenerational exposure approach to address the transgenerational toxicity of ibuprofen in Daphnia magna across an environmentally observed to upper end concentration range (0.5-500 μg/L). The experimental design encompassed direct F0 exposure, continuous exposure until F3 (F3C), and cessation-of-exposure in F3 (F3R). Ibuprofen exposure significantly compromised growth and reproductive capacity of Daphnia magna, induced morphological deformities including tail spine curvature and eyes abnormalities, impaired swimming behavior like the decreased speed and distance. In particularly, these adverse effects persisted across generations, manifesting in both F3C and F3R lineages. The investigations revealed that ibuprofen disrupted endocrine signaling pathways critical for molting and reproduction (EcR, CYP314, VTG) through COX inhibition, alongside mitochondrial dynamic imbalance and oxidative stress. Whole-genome bisulfite sequencing demonstrated generation-specific DNA methylation patterns: widespread epigenetic disruption in F0, "adaptive reprogramming" in F3C, and "transgenerational imprinting" in F3R. Differential methylation in key pathways (FOXO signaling, autophagy, actin organization) provided compelling epigenetic evidence for the observed transgenerational toxicity. Overall, the results indicated that measurable adverse effects can occur at environmentally realistic concentrations (0.5-5 μg/L), whereas mechanistic and epigenetic signatures were most evident under upper-end/hotspot scenario exposure (50-500 μg/L), highlighting the value of incorporating multigenerational assessments into ecological risk evaluation frameworks.