WASHINGTON – An effort by environmental groups to block the Bush administration from implementing regulations on mercury pollution power plants was rejected by a federal appeals court.

Without comment, Judges David Sentelle and Janice Rogers Brown of the U.S. Court of Appeals for the District of Columbia denied a motion to halt immediately the regulations adopted in March by the Environmental Protection Agency.

The rules set a nationwide cap on mercury emissions from about 600 coal-burning power plants and puts a ceiling on allowable pollution for each state beginning in 2010. Individual plants, however, can avoid cleanups by buying pollution allowances from plants well under allowable limits.

Environmental and health advocacy groups plus 14 states, including Maine, have asked the appeals court to order EPA to rewrite the regulations to require that all plants install within the next three years the best available technology for cutting mercury pollution. In the meantime they asked the judges to set aside the regulations until the case can be heard.

Other states challenging EPA’s rules are California, Connecticut, Delaware, Illinois, Massachusetts, Minnesota, New Hampshire, New Mexico, New York, Pennsylvania, Vermont and Wisconsin.

Advocacy groups Environmental Defense, National Wildlife Federation and the Sierra Club say EPA’s regulations, written with the help of industry lobbyists, should force power plants to install technology to capture mercury emissions.

EPA officials maintain that the agency’s approach will reduce mercury pollution from power plants in half by 2020, from 48 tons a year now to 24.3 tons, and eventually by 70 percent.