Virginia and Maryland officials have began "very tentative" negotiations over a possible interstate compact that would sharply increase oil tankers responsibility for any spills in Chesapeake Bay, Virginia Attorney General Anthony F. Troy said yesterday.

In a speech in Williamsburg, Troy cited difficulties Virginia officials have had in collecting clearup costs for recent bay oil spills, and said oil shippers should be held, responsible for the full costs of any pollution they cause:

"Our unfortunate experience with the Chesapeake Bay has shown that the present limits of liability are far too low," Troy said is an address to the Virginia Pollution Control Association.

Under present U.S. law, oil spill damage are computed under a formula of $100 per gross ton of spilled oil - a schedule that often allows some large polluters to claim they cannot be assessed for the full cleanup costs, Troy said.

Furthermore, he said one shipper who is being sued by Virginia for $750,000 in damages resulting from a huge barge spill is invoking a rule of maritime law in an effort to reduce his potestian fine more sharply. That shipper is claiming that the state cannot be awarded more than the cost of the vessel involved in the accident.

The present rules fail to "adequately protect the interests of Virginia consumers and citizens who now stand in line to pay the balance, of the cleanup costs of a major oil spill," Troy said.

In an interview after his speech, Troy said any proposed compact that result from the meetings will have to be approved by the legislatures of both states, as well as Congress, before it can be enacted. That means that any change in the present laws may be "a couple of years away," he said.

Troy said his office raised the suggestion of the compact and that Maryland Maryland official [TEXT ILLEGIBLE] to the [LINE ILLEGIBLE] meeting. The proposal will [WORD ILLEGIBLE] again at a conference between the state officials on bay problems in late April , Troy said.

If Virginia had a compact with a more severe penalty for polluters, Troy said, the current-dispute over a proposed oil refinery in Portsmouth, Va., might have been avoided. One of the principle fears environmental groups have raised about the project is a fear that oil spills from tankers docking at the refinery would harm marine life in adjacent waters, he said.

With the assurance the polluters would have to pay the full costs of any pollution there, some of the objections to the refinery might have been cut short, he said.

In a separate development, officials of the Virginia State Water Control Board in Richmond said they began testing two Shenandoah valley river beds yesterday for traces of mercury, which has been discovered in a 12-mile stretch of the river near a Waynesboro chemical plant.

The state tests will be conducted along about 100 miles of the South River and the South Fork of the Shenandoah River from Waynesboro north to the West Virginia line, a spokeswoman for the board said. The rivers flow into the Potomac River in West Virginia.

Last week officials of the Du Pont Company, which runs a major systhetic fiber plant in Waynesboro, met with Virginia officials to report they had discovered mercury in sediments taken from the river bottom.