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Significant reductions in mercury emissions will be necessary just to stabilize current levels of the toxic element in the environment, according to new research from a team led by Harvard University.
Surface reservoirs, such as soil, air and water, hold an enormous amount of mercury from past pollution going back thousands of years. Scientists believe it will continue to persist in the ocean and accumulate in
fish for decades to centuries.
"It's easier said than done, but we're advocating for aggressive reductions, and sooner rather than later," says
Helen Amos, a PhD candidate in Earth and Planetary Sciences at the Harvard Graduate School of Arts and Sciences. The findings of this study were published in a recent issue of
Global Biogeochemical Cycles.
Amos worked with a team of researchers from the the Atmospheric Chemistry Modeling Group at the Harvard School of Engineering and Applied Sciences (SEAS) to collect historical data concerning mercury emissions as far back as 2,000 BC. The team has also been building environmental models of mercury cycling that captures the interactions between the atmosphere, oceans and land.
Most of the mercury emitted to the environment ends up in the ocean within a few decades, the model reveals. The mercury remains in the ocean from centuries to millennia. Currently, emissions of mercury are mainly from coal-fired power plants and artisanal gold mining. The mercury is thrown into the air, rained down into lakes, absorbed by the soil and carried by rivers, eventually finding its way to the sea. Once there, aquatic microbes convert it to methylmercury, the organic compound that accumulates in fish, finds its way to our dinner plates, and has been associated with neurological and cardiovascular damage.