Mercury in Fish from National Parks

Mercury (Hg) is a toxic, global contaminant that threatens ecosystem and human health. Human activities have increased atmospheric concentrations 3-5 fold during the past 150 years. Airborne Hg enters environmental cycles in complex ways, resulting in the contamination of even remote places. The National Park Service (NPS) protects some of the most pristine and sensitive wilderness in North America. There is concern that atmospherically deposited Hg could threaten the ecological integrity of aquatic communities in the parks and the wildlife that depend on them. In this study, the NPS and U.S. Geological Survey examined Hg concentrations in more than 1,400 freshwater fish from 86 sites across 21 national parks in the western U.S., extending over a 4,000 km distance. What is this study about?