Alexandria Sheriff Michael E. Norris, whose eight-year tenure has been marked by controversy, lost his bid for a third term yesterday, while in Arlington, County Board member Ellen M. Bozman crushed her opponent to win a fourth term.

Norris, a Republican who had been exonerated after almost a year of scrutiny connected to a police drug probe, was defeated by independent challenger James H. Dunning, a federal probation administrator, who won 59 percent of the vote.

"It is quite apparent that Alexandria's citizens have a different set of political priorities," Norris said in a concession speech only 40 minutes after the polls closed. "I am proud to have led the sheriff's office in a critical time of need."

Although Norris is regarded as an innovative law officer, his involvement in personal and professional controversies in recent years generated headlines and provided fodder for Dunning's campaign.

Last month, Norris, who runs the jail, was criticized for accepting a $1,500 campaign contribution from the president of a company that provides health services to jail inmates. Norris defended his action, saying it was not wrong to accept the money because the City Council, and not his office, awards the health services contract.

Three weeks ago, it was revealed that a woman who worked in his office for six weeks last summer was wanted on felony charges in North Carolina. Norris said the city's personnel office is responsible for background checks of employes in his office.

Dunning questioned the propriety of accepting the money and said the other incident posed the potential for "a very serious breach of security."

Norris' life style also has generated controversy since his disclosure that he socializes with gay friends.

In Arlington, Bozman, with 70 percent of the votes, defeated Richard J. Herbst, a Commerce Department analyst making his first run for office, Both campaigned as independents, she with the backing of county Democrats and he with the endorsement of county Republicans.

"It's still an exciting prospect," Bozman said about winning her fourth four-year term, a feat accomplished by only two others in at least 60 years. She won every precinct except Aurora Hills, Herbst's home base.

The race was a low-key one in which both candidates stressed the need to protect residential neighborhoods from high-rise encroachment.

Bozman emphasized her experience on the five-member board and efforts to improve the quality of life in the county. Herbst, a lawyer who has long been active in South Arlington affairs, focused on his role as a community activist, but he had been handicapped by his lack of a countywide presence.

"I think it's an incredible chore for someone to take on a 12-year incumbent," he said last night.

In Loudoun County, Democratic Commissioner of Revenue Catherine B. Ashby defeated Republican Susan Diedrich Rutherford for a four-year term. Ashby was appointed to the office in July to serve out the term of Lee Keyes, who resigned after an alcohol-related car accident.