Mercury, a harmful element, is released into our environment primarily through activities such as coal mining and burning. This toxin eventually finds its way into the ocean, where it accumulates in fish, particularly tuna, a staple in many diets worldwide.
Despite efforts to reduce mercury levels in the air since 1971, levels in tuna have remained steady. This is because old mercury stored deep in the ocean resurfaces and contaminates the waters where tuna roam.
When mercury enters marine ecosystems, it transforms into methylmercury, its most dangerous form. Tuna absorb methylmercury by consuming contaminated prey, which in turn exposes humans when they eat tuna.
Mercury exposure poses significant risks, especially to vulnerable populations like unborn babies and young children. It’s also been associated with cardiovascular disease in adults. Governments worldwide have taken steps to curb mercury emissions from various sources, including coal mining, burning, industrial activities, and waste processing.
Yet, despite these efforts, mercury levels in tuna haven’t significantly decreased. Recent research analyzed nearly 3,000 tuna samples from different oceans over several decades. It found that mercury levels in tuna have stayed constant since 1971, except for a spike in the north-western Pacific in the late 1990s due to increased coal consumption in Asia.
This stability suggests that past emissions, even dating back centuries, continue to affect marine environments. Legacy mercury stored deep in the ocean resurfaces and contaminates surface waters where tuna feed, leading to an ongoing supply of historical mercury.
This study underscores the lasting impact of human activities on our environment and emphasizes the importance of ongoing efforts to reduce mercury emissions and safeguard marine ecosystems.
