Mercury accumulation over the Holocene revealed from a Greenlandic ice core.

Abstract

Mercury is a contaminant of global health concern, but anthropogenic impact on preindustrial mercury cycling remains poorly constrained. Here, we report a high-resolution Greenlandic ice core record of the mercury concentration and accumulation flux over the entire Holocene. We show that the Greenlandic mercury accumulation was shaped by volcanic eruptions, climate excursions, and anthropogenic activity in the past millennia. Mercury accumulation has increased remarkably since the 13th century and further intensified in the past two centuries, which closely mirrors estimated anthropogenic emissions. However, anthropogenic impact was evident long before that, as mercury accumulation entered multiple periods of continuous increase for almost two millennia following early anthropogenic mercury uses. Our result suggests that human activity might have started to impinge on Greenlandic mercury cycling earlier than previously thought and that assessing all-time anthropogenic mercury emissions needs to account for a longer period than the current estimates.