BBC:
“Mercury levels in tuna had remained constant between 1971 and 2022, the scientists found, apart from an increase in the north-western Pacific, in the late 1990s, linked to growing mercury emissions in Asia, sparked by rising coal consumption for energy. The constant levels may be caused by emissions many decades or centuries ago, the researchers said.”You have this huge amount of legacy mercury that is in the deeper subsurface ocean,” Ms Médieu said. “This mixes with the surface ocean, where the tuna swim when they feed. “That’s why you have a continuous supply of this historic mercury that was emitted decades or centuries ago.”
Co-author Anne Lorrain, also from from the French National Research Institute for Sustainable Development, told BBC News: “Our study suggests that we will need massive mercury emissions reductions to see a decrease in tuna mercury levels. “Even with massive reduction in mercury emissions, our results show that we will have to be patient before seeing a change in tuna mercury levels.”
