Although politicians like to believe that their work lives on long after they are gone, it's doubtful that many think in terms of centuries. But in Arlington County, the work of Colonial legislators may have stayed on the books too long for one member of the county board.

At a hastily-called press conference last week, the subject of which was a closely guarded secret before hand, Dorothy T. Grotos revealed that her service on the board and a federal advisory commission apparently violets a long-forgotten 200-year-old state law.

That statue says that persons holding federal appointments (Grotos is a member of the C & O Canal Advisory Commission) may not hold certain other offices unless specifically exempted. According to county attorney Jerry K. Emrich, the statue was unearthed by a unnamed staff member who brought it to his attention.

An arcane law dating to the 1930's forced the resignation of board member Ellen M. Bozman on Dec. 6 for the remaining 25 days of her first-four year term. Bozman had been serving on the board and on a local Health Care Commission since 1975.

Last month, Bozman, and independent and part of the liberal board majority, was re-elected to a second term with endorsements from both the local Democratic party and the nonpartisan Arlingtonians for a Better County.

In November, she resigned from the Health Care Commission, which is charged with developing nursing homes in Arlington, shortly after she and the other board members learned about the violation from Emrich. Emrich said he discovered the statute while doing legal research on ohter matters.

Grotos, an independent, was elected to the board in 1975 with Republican endorsement. As a Dec. 10 meeting she cast the swing vote defeating a motion to resent Bozman for the remainder of her first term.

Flanked by her attorney Larry Suiters and Enrich, Grotos said she called the press conference to "share the news with the people of Arlington so that I can get on with the (holiday) season."

Emrich and Suiters said Grotos will continue to serve on both the county board and the canal commission until legal question is resolved. Suiters, echoing Emrich's words, characterized the 200-year-old law as a technically and noted that resolution of the legal question could conceivably take several years. They were uncertain how the question would be resolved.

Grotos refused to comment on whether the staff member's discovery was "in retaliation" for her vote not to re-seat Bozman. Bozman, her expression grim, sat in the back of the largely empty county board room during the 20-minute press conference.