Three reporters on the metropolitan staff of The Washington Post were awarded prizes yesterday in the Maryland-Delaware-D.C. Press Association's 1980 editorial contest.

Dale Russakoff, 27, won first prize in the association's public service series category for her articles on the Job Corps. Her series, "The Job Corps: Epilogue to the Great Society," traced what has happened to the youths from the hills of Kentucky and inner city of Baltimore since they left the Job Corps' first center at Catoctin, Md., in the mid-1960s.

Neil Henry, 26, won first prize in the feature seriers category for the articles he wrote after living three months as a penniless drifter in Baltimore and Washington. His 12-part "Down and Out" series described life at the mission houses, labor pools, blood banks and heating grates that comprise the world of the most destitute among us.

Janet Cooke, 26, won second prize in the news story category for her article, "Jimmy's World," about an eight-year-old heroin addict in Washington whose habit was accepted by his mother and satisfied by his mother's boyfriend.

First prize in the news story category went to four Baltimore NewsAmerican reporters for their article, "The Snowball Tragedy," about an elderly Baltimore-area man who shot and killed a teen-ager who was among a band of neighborhood youths who had pelted his house with snowballs. Other first prize awards went to John Fialka of The Washington Star for a news series and Thomas Crosby of The Star for best local government coverage.