Today, a year after the oil tanker Argo Merchant ran aground 27 miles southeast of Nantucket Island, threatening the beaches of Cape Cod and the world's most bountiful fishing grounds with environmental disaster, there is little evidence of appreciable damage to beaches or marine life.

Indeed, no physical evidence remains even of the 640-feet Liberian vessel, which broke up in the 5 knot tides whipping around the sandy Nantucket Shoals, ro the 7.6 million gallons of heavy fuel oil from Venezuela that spilled into the sea, for a time threatening the Georges Bank fishing grounds, but ultimately drifting off into the North Atlantic, where it presumably sank.

"It's difficult to measure the cost to the North Atlantic sea bottom," said William Woodward, legislative assistant to cape and island Rep. Gerry E. Studds (D-Mass.). "There was some damage to fish eggs. Pollock and cod were hit the worst. But it will be two to three years before we know if the damage will be commercially significant."

Measuring the cost of the Argo Merchant mishap which scientists once feared would become New England's ecological castrophe of the century - is a bit easier. Congress' General Accounting Office has pegged the total cost at $5 million.

Half of that reflects the commercial value of the lost oil (* enough to heat 6,500 houses for an entire bitter New England winter).Of the remaining costs, $1.7 million represents the expense of the Coast Guard's largely ineffective clean-up effort.

The remainder is the cost of research, still inconclusive, into the consequences of the spill - studies undertaken largely by the National Oceanographic and Atmospheric. Administration and the Massachusetts Office of Environmental Affairs. The total public cost was further reduced recently when roughly $1 million from an emergency fund kept by oil tanker owners - to head off tighter legislative controls of their industry - was given to the Coast Guard and the state.

The main reason the predictions of doom didn't materialize was simply the failure of the oil slick to come ashore. "If the spill had occurred in the summer," theorized Woodward, "the prevailing wind would have forced most of it ashore, and the beaches would have been ruined. On the other hand, if the seas had been calmer, the oil might have been pumped out of the vessel before it broke up."

Meanwhile, the scientific community remains cautious about offering conclusions concerning ecological impact. A conference, "In the Wake of the Argo Merchant," is set for Jan. 11-13 at the University of Rhode Island's Center for Ocean Management Studies.

At that event, said scientist John Farrington of the Woods Hole Oceanographicc Institute on Cape Cod, scientists from government, unversity, and private laboratories will bring together for the first time all related data and try to agree on some meaningful conclusion. "The only thing you could say for certain," Farrington said, "is that we are now better prepared in knowing how to react to future spills."

Joseph Baerlein, assistant to Massachusetts Environmental Affairs Secretary Evelyn Murphy, pointed out that four days after the Argo Merchant ran around, as oil was still seeping from its damaged hull, Massachusetts Gov. Michael Dukakis had not yet officially been notified of the growing danger to his state's coastline. The Coast Guard now promises to notify offiicials of affected states immediately. Additionally, state officials here are still trying to convince the federal government to locate an emergency cleanup team somewhere in the Northeast. The Atlantic strike force team that handled the Argo Merchant spill had to be flown in from Elizabeth City, N.J.

There has been some progress in the legislation designed to make spills less likely and those responsible for them more accountable. A stringent oil spill liability bill, cosponsored by Studds and Rep. Mario Biaggi (D-N.Y.), has passed the House and Senate passage in January is likely.

A tanker safety law, to provide federal regulation both of domestic and foreign tanker construction and for the training of their crews, has been introduced and hearings held.

And, an outer continental shelf bill to provide safeguards as offshore oil exploration continues, died in the House Rules Committee after being twice approved by the Senate.