As a child, Vic Ellis never thought much about tossing a bottle or a soda can into the Anacostia River. Yesterday, he paid for it.

Ellis, now a construction supervisor from Baltimore, was one of nearly 100 volunteers who donned boots and old clothing to wade into thigh-high mud along the shores of the Anacostia or struggle through the tangled underbrush along the banks to clean it of human-generated debris. Several times Ellis became mired in the foul-smelling muck, once losing a boot and feeling the mud ooze between his toes.

"It needs to be done," said a sweating Ellis, who was drawn to the river because he wanted to clean up the mess that he and other Washington area residents have created.

The Anacostia River cleanup effort was one of hundreds of projects statewide during the annual Community Service Day in Maryland. Thousands of people from throughout the state spent part of yesterday planting trees, working at senior citizens homes, painting shelters and performing other good-will activities. In Montgomery County, workers removed trash from Rock Creek Park near Connecticut Avenue.

Many of the day's activities were related to the environment. The Anacostia and Potomac rivers and their tributaries were treated to fall spruce-ups through a project called "Healing a River for the Life of the Chesapeake." The efforts drew volunteers from Maryland as well as volunteers in the District, Virginia and West Virginia.

At the Anacostia in Bladensburg, the intermittent drizzle brought out only a tenth of the expected 2,000 volunteers to clean the river. They hauled out old tires, a rusted grocery shopping cart, pipes and bags of bottles, beer cans and Styrofoam cups and food containers.

At Colmar Manor Anacostia River Park, parts of which used to be a landfill, others planted an acre of oak, green ash, white pine and other varieties of saplings. Children seeded the ground with wildflowers and azaleas.

Several politicians running for reelection, including Gov. William Donald Schaefer and Prince George's County Executive Parris N. Glendening, crowded into a speedboat for a 10-minute ride down the Anacostia to lend their support.

Despite the lower-than-expected turnout, organizers said the campaign to heal a river was a good follow-up on the Earth Day activities last spring that drew 28,000 people to a similar cleanup of the bay. "This is a good effort," said Estelle Balka, an environmental protection specialist for the hazardous waste division of the federal Environmental Protection Agency.

For many who came out yesterday, the cleanup was their first involvement in environmental work. Several people said they came because they saw a flier at a store or heard an announcement on the radio.

Diana Dorsey, of Arlington, heard a pitch on a local station and got two of her friends to join her. The three of them struggled for several minutes to uproot a large rusted pipe lodged in the embankment near the Bladensburg Marina, finally busting it in half and carrying it in pieces to a waiting trash truck.

"The real motivation is that if everyone gave an hour, how much cleaner would this river be? A lot cleaner," Dorsey said. "I think physical cleaning is very rewarding . . . finding large hunks of garbage and taking it away."

Patti Rivas brought her four children, ranging in age from 2 to 5 years. She said she talked to them for weeks about the environment, the destruction of the rain forests and the impact on the earth. The children planted flower seeds and picked up trash around the bank.

"I felt it is a learning experience for them," said Rivas. "We just recently moved into Riverdale, and this is part of our community now."