More than two weeks after the accident at Three Mile Island nuclear power plant, the White House yesterday designated the Environmental Protection Agency as coordinator for the eight federal agencies that have been monitoring radiation effects in the area.

The lack of overall direction in the radiation data collection up to now has been a concern among some of the agencies involved and on Capital Hill.

"Somebody has to be made the focal point," was the way one agency head put it just an hour before it was disclosed that the White House coordinator, Jack Watson, had selected EPA to do the job.

Watson decided to name a lead agency because "so many agencies were there and all were monitoring different things," according to one source.

"The public must be assured of their safety with the most credible environmental data," the source said in describing why EPA was chosen.

Other sources, however, said the choice reflected both the political and bureaucratic problems that now dog today's controversy over the long-term health hazards of exposure to low levels of radiation.

The Nuclear Regulatory Commission, up to yesterday, served as single spokesman for the findings of the federal monitoring system. But NRC neither directed the collection nor distributed the findings of one agency to any others.

Monitoring officials at the plant site had expected NRC to be named coordinator for the continuing monitoring effort, but criticism of NRC's delay in recognizing the radiation problem has hurt its public credibility in the area.

The two other federal departments most familiar with low-level radiation problems-the Departments of Health, Education and Welfare, and Energy-reportedly were ruled out because of their opposing views on the radiation health problem.

DOE scientists have consistently played down the longterm health risk. HEW officials led by Secretary Joseph A. Califano Jr. have recently joined with those who believe there are serious questions still to be answered about the relationship between low doses once considered almost risk free and cancers that developed 10 or 20 years later.

"They avoided picking sides," was the way one official described the choice of EPA as coordinator.

The federal coordination process was handled informally in the initial days after the accident by late afternoon phone calls among the first agencies on the scene-the Department of Energy group, which arrived the first day to sample soil and vegetation, and HEW's Food and Drug Administration, which looked at milk and other food.

By April 1, four days after the accident, these monitoring efforts were supplemented by EPA personnel looking at air and water radiation; NRC monitors of offsite radiation; Center for Disease Control investigators following individual exposures; National Institute for Occupational Safety and Health workers following plant workers and National Institutes of Health personnel taking samples and eventually giving examinations.

To handle the increase in information, a daily 5 p.m. meeting was arranged at the hangar at Capital City Airport used by DOE as its headquarters building. At these meetings, which continue to this day, each agency's representative would stand before a map and report what his group was doing and what it had found during the previous 24 hours.

"You can't believe the confusion that went on," one participant said, recalling the first days of the accident.

More recently, another added, "we were wondering who we would turn our information and samples over to for follow-up purposes."

Preservation and eventual integration of all the data collected would be needed as part of the health follow-up to the accident.

"We also need a coordinated record for the (congressional) investigations," one official said.

It was learned yesterday that an interagency group was reviewing the dose level figures presented last Tuesday to a Senate health subcommittee with hopes of producing a revised estimate early next week.

"It won't be much above" the 80 millirem number given the senators as the maximum possible dose, one source involved in the review said yesterday. The average American receives an annual dose of 100 millirems from natual background radiation and the suggested annual permissable level to the public is now set at 500 millirems.

At the 80 millirem level, no additional cancers should develop among those people exposed, federal officials told the senators this week. CAPTION: Picture, JACK WATSON . . . "so many agencies were there"