"Emission controls required on out-of-state power plants have yielded big reductions in mercury pollution in Western Maryland's air, a study has found. So far, however, the state's fish remain as contaminated with the toxic chemical as ever, researchers say.

Long-term monitoring at a reservoir in Garrett County saw declines of 43 percent to 75 percent in airborne mercury levels there from 2009 through last year, according to the study. Those declines tracked closely with emission reductions measured at coal-burning power plants not far away in Ohio, Pennsylvania and West Virginia.

The findings, published online recently in the journal Environmental Science & Technology, provide "compelling evidence" that regulating mercury emissions from U.S. power plants can produce significant environmental benefits downwind, conclude the authors, Mark Castro of the University of Maryland Center for Environmental Science and John Sherwell of the state Department of Natural Resources."

Timothy B. Wheeler reports for the Baltimore Sun December 8, 2015. [2]