Mercury fluxes at the studied peatland in the county of Västerbotten in Northern Sweden (grams per square kilometer and year). Illustration: Michael Kvick, SLU

“The first full year of measurements on a peatland showed that it is losing twice as much mercury gas back to the atmosphere as is being deposited on the peatland by the rain. This is a stunning finding because it means that recent reductions in atmospheric mercury concentrations (up to a 50 percent decrease in the last 20 years) have reversed the direction of mercury flows between the atmosphere and the peatland.”, says Mats Nilsson, SLU. In an article published in the highly regarded journal Scientific Reports, the research team estimates that given the rate at which the peatland is now losing mercury back to the atmosphere, it will take just a few decades for all of the mercury pollution accumulated in the peatland to have disappeared, with most of it going back to the atmosphere. This is very good news since peatlands hold so much accumulated mercury pollution that is readily available to the fish in downstream lakes. The fact that it looked like there was nothing that could be done to improve the mercury pollution situation has made it easier to focus on new contaminants which might be out there, rather than the established health threat from mercury in freshwater fish that appeared impossible to solve. “A seemingly eternal problem suddenly seems like it is on its way to being solved much, much faster than we could have hoped, so long as the successes in reducing mercury pollution are not reversed”, says Kevin Bishop. If the findings prove valid for many peatlands, this will strengthen the importance of United Nations led efforts to reduce global mercury pollution for Sweden and countries that have similar problems with mercury in freshwater fish, including Finland, Canada and the United States.