About 130 nurses in Montgomery County are expecting a Christmas bonus of sorts -- a share in $800,000 in back pay that the state appeals court has ruled the county owes them, following a legal appeal by their union.

A three-member panel of the Court of Special Appeals of Maryland ruled unanimously this month that the county nurses -- who disputed a county pay-classification study of nursing jobs -- should re ceive retroactive pay increases dating from 1981.

The dispute between the county and its nurses began in 1984 when the county completed a scheduled review of the pay scales for nurses who work in schools, county clinics and the health department.

That review, which had started in 1979, recommended that the nurses' pay scale be increased two grades. The nurses appealed the pay raise to the Montgomery County Merit System Protection Board and asked, based on the physical demands and hazards of the job, that the pay scale be increased another grade.

The board agreed to the grade and the county did not dispute the additional pay. What became an issue, however, was the date when the retroactive pay should be calculated. The nurses wanted pay dated since 1981, arguing that the county's pay review process took longer than six months, a standard that the county set as reasonable. The county asserted that some retroactive pay should be paid, but only from when the new schedule was accepted.

The lump-sum payment to each nurse is expected to be $4,000 to $6,000, about 5 percent of the recipient's salary.

The county can appeal the decision to the Court of Appeals, the state's highest court, within 45 days. Linda Berk, senior assistant county attorney, said yesterday that the county was "disappointed in the decision. We haven't made any decision yet on further action."

Representatives for Local 400 of the United Food and Commercial Workers, which represented the nurses, said yesterday the impact of the decision was still "sinking in" for some nurses, all but four of whom are women with one to two years experience in county government.

"We just kept pluggin' away," said Iris Lavery, shop steward and a nurse with 12 years' experience in the school system. "The feeling is, after all this time, we're going to see something very positive for nurses and nursing."

"This puts to rest the claims of the county that the law doesn't allow the Merit Board to deal with systemic problems and reach out and correct unfairness," said William Thompson, attorney for the Local 400 case.

Representatives of UFCW said yesterday that the back pay decision was the largest award ever won by the 40,000-member local.