Toxic cyanobacteria, including Microcystis, produce harmful toxins that affect aquatic ecosystems and human health. Biotreatment using macrophytes shows promise in mitigating these blooms. This study investigates the bioaccumulation dynamics and biochemical responses of two aquatic macrophytes, Pistia stratiotes and Ceratophyllum demersum, in removing microcystin from contaminated water. P. stratiotes showed high initial bioaccumulation rates with rapid microcystin uptake, which is effective for short-term bioremediation. C. demersum has shown stable bioaccumulation. Biochemical analyses have revealed the activation of plant antioxidant defenses, with both macrophytes showing an increase in carotenoids, glutathione (GSH), and antioxidant enzymes such as superoxide dismutase (SOD) and glutathione-S-transferase (GST) concentrations. In particular, C. demersum has maintained higher antioxidant levels, contributing to its sustained capacity and resilience. Fluctuations in malondialdehyde (MDA) indicated oxidative stress, with P. stratiotes managing such stress through its defenses. Principal Component Analysis (PCA) supports these findings: Pistia’s first two components explained 25.09% and 20.71% of the variance, with Carotenoid and Chl contributing strongly to PC1, and MDA and GST influencing both components. For C. demersum, PC1 and PC2 explained 21.79% and 19.78% of the variance, with Carotenoid and Chl a being major contributors, while SOD and GSH played significant roles in sample differentiation. Integrating both plants into bioremediation strategies could optimize microcystin removal: P. stratiotes offers rapid initial detoxification, while C. demersum ensures continuous, long-term remediation. This combined approach enhances the efficiency and sustainability of phytoremediation. Future research should optimize environmental conditions and explore synergistic effects among multiple plant species for more effective and sustainable bioremediation solutions.

Background and Aim: Cyanobacterial blooms, driven by anthropogenic and climatic changes, pose significant ecological and health threats. This study investigates the long-term effects of microcystins (MCs), potent cyanotoxins, on cattle at Lake des Oiseaux, a Ramsar-listed wetland in Algeria. Aligning with the “One Health” framework, the research evaluates the biochemical, histological, and oxidative stress impacts of MCs on livestock as environmental sentinels. Materials and Methods: A herd of 40 cattle (20 exposed and 20 non-exposed) was studied during the summer bloom period of 2019. Blood and liver samples were analyzed to assess biochemical markers (ALT, AST, ALP, GGT, etc.), histopathological changes, and oxidative stress parameters (GPx, CAT, SOD, LPO and GSH). Results: Exposed cattle exhibited significant elevations in liver enzymes and oxidative stress markers, indicating hepatic inflammation and redox imbalance. Histological analysis revealed macrovacuolar steatosis, fibrosis, and bile duct dilatation. Antioxidant enzyme activities (GPx, CAT and SOD) were reduced, with notable depletion of GSH levels and increased lipid peroxidation. These findings reflect the cumulative cytotoxic effects of MC exposure. Non-exposed cattle showed no such changes. Conclusion: Long-term MC exposure disrupts liver function and induces oxidative stress in cattle, implicating significant risks for both animal and human health. The bioaccumulation of cyanotoxins in livestock emphasizes the urgent need for preventive measures, including water monitoring, restricted livestock access to contaminated sites, and farmer education. These strategies are vital to mitigate risks under the “One Health” approach, ensuring sustainable livestock and public health. Keywords: cattle health, cyanobacterial blooms, environmental pollution, lake des oiseaux, microcystin, one health, oxidative stress.