Researchers warn of legacy mercury in the environment

Without stringent emissions reductions, future increases in ocean mercury levels are likely to be greater than anticipated. Environmental researchers at Harvard University have published evidence that significant reductions in mercury emissions will be necessary just to stabilize current levels of the toxic element in the environment. So much mercury persists in surface reservoirs (soil, air, and water) from past pollution, going back thousands of years, that it will continue to persist in the ocean and accumulate in fish for decades to centuries, they report. "It's easier said than done, but we're advocating for aggressive reductions, and sooner rather than later," says Helen Amos , a Ph.D. candidate in Earth and Planetary Sciences at the Harvard Graduate School of Arts and Sciences and lead author of the study, published in the journal Global Biogeochemical Cycles . Amos is a member of the Atmospheric Chemistry Modeling Group at the Harvard School of Engineering and Applied Sciences (SEAS), where researchers have been collecting historical data on mercury emissions as far back as 2000 BC and building new environmental models of mercury cycling that capture the interactions between the atmosphere, oceans, and land. Their model reveals that most of the mercury emitted to the environment ends up in the ocean within a few decades and remains there for centuries to millennia.