A Virginia Senate committee today approved legislation that would permit five Northern Virginia jurisdictions to individually impose a 4 per cent tax on gasoline sales starting next July 1 to help pay the region's mounting Metro costs.

The measure, approved on a 7-to-4 vote by the Senate Local Government Committee, now goes to the full Senate where its chances for passage are uncertain, in part because of the Virginia legislature's traditional reluctance to use gabline taxes for any purpose other than highway construction.

The gas tax, which could provide $11 million a year to ease the financial burdens of the Northern Virginia governments, was approved by the legislature last year, but with the provision that the governing bodies in Fairfax City, Fairfax County, Alexandria, Arlington County and Falls Church all had to approve the tax before it could be imposed.

However, Fairfax City refused to impose the tax, saying that it did not need the revenues to pay for its share of the region's $11 million Metrobus operating deficit. Thus the tax was not imposed anywhere. Fairfax City officials have said they are not opposed to passage of a local option gas tax.

Although both sides of the gas tax issue had a plethora of speakers ready today to discuss the relative merits of the tax, committee chairman Peter K. Babalas (D-Norfolk) limited each side to one speaker, Arlington Board Chairman Joseph S. Wholey spoke in favor of the tax and Gary Denton, of the Virginia Gas Retailers, spoke in opposition.

The tax is needed, Wholey said, not only to help pay transportation costs in Northern Virginia but to maintain essential services" in the county at a time when Arlington is facing a severe budget crunch.

Metro, Wholey said, is already "taking up 20 per cent" of the revenues from the county's real estate tax, with homeowners bearing "the bigger share of the burden." Most of the county's population lives in apartment buildings, whose real estate assessments go up at a slower rate than single-family homes.

As a member of the Metro board, Wholey also offered to treat the committee to an account of current Metro cost-saving endeavors in order to further enhance the chances for the committee's approval. But the committee, like all others in the General Assembly, is inundated with bills it must complete action on by Friday. Bobalas wearily dismissed Wholey's offer, saying, "I think we'd rather not go into it."

Denton contended that "few commodities are so heavily abused as gasoline." The tax, he said, would create an unfair imbalance in an already competitive business, since customers would simply buy the gas in whatever Northern Virginia jurisdiction does not levy the tax, or in Maryland or the District of Columbia.

The state would also suffer a loss if the tax becomes law, Denton said, since customers transferring their business to stations in Maryland or D.C would deprive the state of its 9 cents per gallon state excise tax.

Denton also said after the vote that the tax could produce "disastrous effects" on the Northern Virginia area's 536 gas station operators. He said a study done by the Exxon Corp. has shown that a 2-cent increase in the price of a gallon of gas could produce as much as a 30 per cent loss in business.

Sen. Charles L. Waddel (D-Loudoun) was the only Northern Virginia lawmaker on the committee to vote against the bill.

In another action, the Senate Privileges and elections Committee unanimously killed a measure that three Northern Virginia legislators claimed could have helped reduce Metrobus costs in the Washington area. The proposal, which would have brought an end to binding arbitration of Metro labor contracts, was opposed by organizied labor, but was supported by Northern Virginia local governments.

Sen. Joseph V. Gartlan (D-Fairfax), who chaired a subcommittee that recommended against the measure, said the committee believed the arbitration clause represented "a long-standing labor practice" that the legislature should not disturb. "It represents labor peace and we didn't want to run the risk of disrupting that," Gartlan said.

A similar measure still is pending in the House but the decisiveness by which the Senate committee killed the measure indicates that the House measure probably would be killed by the Senate committee even if it passes the House.

To become effective, the measure also would have to be approved by the Maryland General Assembly and Congress since the arbitration clause is subject to the compact between the state and the District of Columbia that established Metro, which runs the regional bus system. Critics of the bill had argued that there was no need for Virginia to act on the measure unless there was some assurances that Congress and Maryland officials also would go along with the changes.

The Senate today approved a series organize part of the state's bureau-of controversial bills designed to recracy, but not until critics had stripped from one bill a provision that would allow the governor to name the executive directors of four separate agencies. Opponents of the bill argued that directors of the State Air Pollution Control Board, State Water Control Board, Council on Higher Education and State Supplemental Retirement System needed to be independent of the governor.

Meanwhile, the House for the third time in as many years, considered and rejected a bill that would abolish the state's so-called rending-the-law program. Virginia is one of four states that still allows prospective lawyers to read and study the law under a qualified attorney for a minimum of three years before taking the bar exam, instead of enrolling in low school.