Earlier this week, we escaped to Rocky Mountain National Park, a short drive from home, for a little snowshoeing. The sun was brilliant, the air was fresh, the snow was firm, and the mountains eternally awesome. We all look to national parks to protect some of the most beautiful areas in our country – and to provide us the opportunity to experience their natural beauty and recreational experiences firsthand.

Unfortunately, despite the stringent protections on National Park air quality, wildlife, water quality, and natural resources, they're not immune from the worst the industrialized world can throw at them. A six year federal survey of environmental quality released this week found evidence of mercury, fertilizer, legal pesticides in harmful concentrations, heavy metals, pseudo-estrogens, plastic precursors, PCBs, the banned pesticides dieldrin and DDT. Many pollutants are thought to arrive by wind deposition from Europe and Asia, though pesticides are likely runoff from local fields.

Fish were particularly found to be suffering from pollutant bioaccumulation; mercury levels in fish from eight parks were found to be well in excess of human consumption thresholds. In Rocky Mountain National Park, effeminized male fish were found, their sex organs atrophied and transformed by exposure to pollutants mimicking the female sex hormone estrogen.

In many cases, high-altitude winds bring power generation pollutants, dust, and heavy metals from Asia, where they are deposited in the Arctic. Mercury deposition from coal-burning power plants was especially high at the remote Noatak National Preserve and at Denali National Park, far from North American industrial sites.

The study is a sobering reminder that, no matter how pristine and beautiful the natural world may still look, human industrial activity results in environmental impacts that are no less grievous for their stealth and subtlety. And, while these data are from national parks, the study serves as a potent reminder that pollution is global in its extent and effect – if it's affecting fish in northern Colorado, it's affecting fish everywhere. And perhaps us as well.