Wood frogs raised in reclaimed wetlands from Athabasca oil sands show reduced metamorphosis and altered thyroid hormone levels

Metamorphosis was delayed or did not occur in Wood frog tadpoles raised in young tailings wetlands.

• Tadpoles raised in young tailings (≤ 7 years) showed delayed metamorphosis compared to those in older tailings (> 7 years) and reference wetlands.
• Thyroid hormone levels indicated disruption, as the T3:T4 ratio was lowest in tadpoles from young, tailings-affected wetlands.
• Tadpoles from older tailings wetlands developed similarly to those from reference wetlands, suggesting reduced toxicity with age.
• Findings indicate that amphibians may complete their life cycle in tailings wetlands that have sufficiently detoxified over time.

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