DETROIT -- A Detroit councilwoman married to Democratic U.S. Rep. John Conyers Jr. pleaded guilty to a federal charge of conspiracy to commit bribery, the latest batch of bad news for a city already shaken by scandals and financial peril.

In a plea deal, Monica Conyers admitted to a "pattern of conduct of accepting bribes" from a waste-management company that was seeking a $47 million sludge-disposal contract from the city. The company, Synagro Technologies, of Houston, was awarded the contract in a 5-4 vote, with Mrs. Conyers...