When it comes to hotspots of toxic heavy metal pollution, Antarctica probably doesn\u2019t come to mind. This remote region is nowhere close to any major city or industrial facility, and yet, mercury is accumulating in the seafloor sediments surrounding the Antarctic Peninsula at an alarming rate.<\/p>\n
That\u2019s according to a study published<\/a> July 27 in the journal Proceedings of the National Academy of Sciences. The findings suggest that increased anthropogenic mercury emissions and climate change are working together to pump more of this dangerous element into the Southern Ocean than ever before, threatening marine ecology.<\/p>\n \u201cThe results reveal that polar warming is turning Antarctica\u2018s cryosphere from a mercury sink into an active secondary pollution source,\u201d the authors write.<\/p>\n From sink to source <\/p>\n Mercury is a neurotoxic heavy metal that can damage both human and environmental health. While it can be emitted by natural sources, mercury pollution mainly stems<\/a> from human activities.<\/p>\n Mercury emissions from industrial facilities such as coal plants, waste incinerators, mines, and cement plants travel hundreds of miles through the atmosphere to Earth\u2019s polar regions. Then, they get deposited onto snow, ice, and open ocean water, eventually becoming incorporated into the ice sheet and seafloor. In this way, both the Arctic and Antarctica have historically served as global mercury sinks, but that appears to be changing.<\/p>\n In this study, researchers reconstructed the past 200 years of mercury source-sink dynamics in the Antarctic Peninsula, the continent\u2019s fastest warming region with the most pronounced glacier melting. They did so by analyzing geochemical and isotropic records from 16 sediment cores collected from the continental shelf off the Peninsula, using a computer model to quantify the amount and sources of mercury deposited in the sediment.<\/p>\n They found that, despite its remoteness from anthropogenic emission sources, the Antarctic Peninsula shelf exhibits a mercury accumulation rate twice the global shelf average. \u201cSince industrialization, this accumulation rate has increased by 160%, making the Antarctic Peninsula one of the major hotspots of marine mercury enrichment,\u201d the authors write.<\/p>\n The model revealed two coupled mechanisms behind this acceleration. Firstly, more mercury is falling from the atmosphere into the Southern Ocean (largely due to rising<\/a> anthropogenic emissions) and as sea ice melts and open water expands, the ocean is able to absorb more mercury from the atmosphere. Secondly, melting glaciers and erosion are releasing mercury that has long been stored in land and ice on the Antarctic Peninsula into the ocean.<\/p>\n \u201cThe coupling of these two loops has increased ice melt-driven terrestrial mercury release by 550% and air\u2013sea exchange by 350%\u201d over the past 200 years, according to the researchers. \u201cThus, climate warming is turning the large historical mercury reservoir in Antarctica into an active secondary pollution source, amplifying polar mercury pollution risk.\u201d<\/p>\n Not just Antarctica <\/p>\n Previous research has suggested that the Arctic is undergoing a similar change. A 2024 study found<\/a> significantly elevated mercury levels in riverbanks and sandbars on the Huslia and Yukon rivers in Alaska. This suggests that permafrost thawed by climate change is releasing stored mercury into Arctic waters. While the exact amount of mercury stored in Arctic permafrost is unknown, it could very well be enormous.<\/p>\n