WASHINGTON — The Environmental Protection Agency said Wednesday that chemical pollution released into the environment fell more than 4 percent from 2003 to 2004, led by declines among the metal mining, electric utility and hazardous waste industries.

But environmentalists noted with alarm that toxic releases in U.S. waterways rose 10 percent, to 241 million pounds of chemicals.

The amount of toxic chemicals released into the environment overall fell to 4.24 billion pounds in 2004, the last year for which figures are available, the EPA said in its annual Toxics Release Inventory (TRI). Some 4.44 billion pounds of toxic chemicals were released in 2003.

The agency said releases of dioxin and dioxin compounds fell 58 percent; mercury and mercury compounds were cut 16 percent; and PCBs went down 92 percent.

Linda Travers, acting head of the EPA’s Office of Environmental Information, said the report ‘‘demonstrates that economic growth and effective environmental protection can go hand-in-hand.’’

The EPA said metal mining disposal and other releases of chemicals fell 14 percent, down to 1.07 billion pounds. Electric utility releases fell 1.5 percent, to 1.05 billion pounds, while hazardous waste releases fell 16 percent, to 195 million pounds.

While government officials see the latest report as an encouraging trend, the EPA is also trying to quit forcing companies to report small releases of toxic pollutants and allow them to submit reports on their pollution less frequently.

The EPA wants Congress to require the accounting every other year instead of annually. The EPA’s annual Toxics Release Inventory began under a 1986 community right-to-know law.

The agency also has proposed using a shortened form that would excuse companies from disclosing spills and other releases of toxic substances if they claim to release fewer than 5,000 pounds of a specific chemical. The current limit is 500 pounds.

About 23,600 facilities provided information on 650 chemicals. In 2001, 25,388 facilities reported findings.

‘‘Unfortunately, this may be one of the last years when the public gets a complete picture of toxic pollution,’’ said Meghan Purvis, an environmental health advocate with the U.S. Public Interest Research Group.

On the Net:

Environmental Protection Agency: http://www.epa.gov/tri/tridata/tri04/index.htm

U.S. Public Interest Research Group: http://www.uspirg.org

American Chemistry Council: http://www.responsiblecare-us.com