What lies beneath the ice? How gadolinium affects Cyclops abyssorum during Alpine winters

Area of Science:

• Environmental toxicology
• Ecotoxicology
• Freshwater ecology

Background:

• Anthropogenic gadolinium (Gd) release from medical contrast agents is increasing.
• Gd contamination in freshwater ecosystems, including fragile alpine lakes, is a growing concern.
• Alpine lakes are vulnerable to pollutants like Gd due to extreme conditions.

Purpose of the Study:

• To investigate the sublethal effects of gadolinium (Gd) on the alpine copepod Cyclops abyssorum.
• To assess Gd-induced oxidative stress under simulated winter conditions relevant to alpine environments.
• To evaluate the ecotoxicological impact of Gd on a non-model zooplankton species.

Main Methods:

• Exposure of Cyclops abyssorum to environmentally relevant Gd concentrations (1-150 µg/L) for 14 days.
• Simulated winter conditions (4 °C, darkness) to mimic alpine lake environments.
• Measurement of oxidative stress biomarkers, including glutathione peroxidase, malondialdehyde, superoxide dismutase, and glutathione S-transferase.

Main Results:

• Increased glutathione peroxidase activity and malondialdehyde levels with increasing Gd concentration, indicating oxidative stress and lipid peroxidation.
• Non-linear responses in superoxide dismutase and glutathione S-transferase suggest physiological thresholds or enzyme inhibition.
• The Threshold-based Integrative Biomarker Response (IBR-T) index showed increased stress at intermediate and high Gd exposures.

Conclusions:

• Gadolinium induces significant oxidative stress in cold-adapted zooplankton like Cyclops abyssorum.
• Assessing contaminant risks in alpine lakes requires considering non-model species and realistic exposure scenarios.
• The findings underscore the potential ecotoxicological impact of medical contrast agents on sensitive freshwater ecosystems.