NORFOLK, AUG. 5 -- Federal officials and leaders of the states ringing the Chesapeake Bay today began their historic summit to chart the rebirth of the polluted estuary, their harmonious rhetoric barely masking private divisions over the ways and means to accomplish that goal.

"It's going to be a hell of a conference," said Torrey C. Brown, Maryland's secretary of natural resources, as he arrived in this port city for an evening of private meetings on a draft agreement for a region-wide bay cleanup.

"This is an opportunity to take the next major step for the bay, to deal with it in a coordinated way," Brown said.

However, even as he and officials from Virginia, the District, Pennsylvania, the U.S. Environmental Protection Agency and conservation groups expressed high hopes for the conference, several of them said that putting teeth in the now vaguely worded compact would be difficult.

"We all know there are certain things that are politically sound, and politically volatile," said Maryland Gov. William Donald Schaefer. "I hope we leave here with some very specific recommendations on where we're going to go, not generalizations."

Parties to the summit are portraying it as an opportunity to rededicate themselves to the restoration of the bay, a project that got its official start in late 1983 when President Reagan and the bay states opened the costly turnaround effort.

The mercurial Schaefer, who is trying to burnish his image on environmental issues, is regarded by Virginia's contingent here as the crucial player in the talks -- and a possible opponent to specific targets for reducing the influx of sewage byproducts that choke off some aquatic life in the bay.

John W. Daniel II, Brown's counterpart in Virginia, said his boss, Gov. Gerald L. Baliles, wants the agreement to require a 30 to 40 percent reduction in the flow of nitrogen, phosphorous and other nutrients into the bay. When asked to name other summit participants who are supporting such a limit, Daniel said: "The EPA clearly is, and the Chesapeake Bay Commission is."

Daniel said that Baliles wants to "toughen" the draft. "The governors have today and tonight -- they are going to focus on the number," Daniel said.

Brown said in an interview that Maryland would accept only a "realistic and doable" target.

"It's hard," Brown added. "The problem is in saying this is a target, or this is a goal, or this is what the limit will be. You don't want to look dumb."

Schaefer, too, showed uneasiness with the target figure Baliles is pushing, using self-mockery to deflect any criticism.

"I read in one of the newspapers today that I will be opposed to anything environmentally sound," Schaefer said.

But, he added, "I'm one of the toughest environmentalists in the state. We're gonna get tough -- tough, but reasonable."

The agreement is scheduled to be signed by late Thursday morning.