The U.S. government has decided to move the current 112 residents off Bikini Island against their wishes because their intake last year of strontium 90 was reaching the danger level, an official told a House Appropriations subcommittee yesterday.

That move could be set as early as next month, the subcommittee members were told, if tests of the Bikinians this month show an increase in the strontium 90 in their bodies.

One reason for a delay, the subcommittee was told, was uncertainty as to whether an alternative island is safe.

John DeYoung of the Interior Department told the suncommittee that Bikini Island "will be off limits for 30 to 50 years."

Department of Energy officials said radioactive cesium and plutonium are so deeply imbedded in the soil that it would be impossible to remove them without taking all the soil off the island.

Twenty-four years ago, Bikini Island was dosed with radioactive fallout from a 15-megaton hydrogen bomb test - one of 23 conducted off the northern part of the atoll from 1947 through 1958.

Nine years ago, the Atomic Energy Commission declared Bikini Island safe for reoccupation by the natives, who had been moved off before the tests began.

Between 1970 and today, about 112 natives returned and stayed, helping prepare housing and other facilities for 400 more Bikinians who live elsewhere in the Marshall Islands.

Three years ago, however, the island residents began to show higher than normal amounts of strontium, cesium and plutonium in their bodies during regular medical tests.

All three radioactive elements, if taken into the body, can over the long term cause cancer.

The source of the troubling elements was food grown in the still-contaminated soil which the natives were eating.

Last year, the levels increased so much that the Department of Interior decided it would have to find another island in the atoll for the Bikinians to live.

At the same time, an imported food program was developed so that those on the island would not eat the radio-actively contaminated, locally grown coconuts, pandanas, breadfruit and other foods. Bikinians were also given canoes and fishing gear since marine life in their lagoon is certified as safe for eating.

Adrian P. Winkel, U.S. High Commissioner of the Trust Territory, told the subcommittee that "even knowing of the danger" those already on the island wanted to remain and "there was some desire of other Bikinians to go there."

An official said later many of those eager to get to Bikini wanted to take part in the free food program.

Asked if there would be a problem getting those on the island to move, Winkel responded, it would not be easy. Last October they refused. He added, however, that now they have been told "it must be done for the absolute safety of them and their children."

Complicating matters is the question of where the Bikinians, both the 112 now on Bikini and the other 400, can safely be moved.

First choice is Enyu, an island in the same atoll that did not get as heavy a dose of radioactive fallout as Bikini Island.

Before Enyu can be declared safe, an aerial radiological survey must be done to determine what pockets of dust-sized plutonium need to be cleaned up and what levels of cesium and strontium exist.

The survey has been delayed for three years, awaiting settlement of bureaucratic fighting in Washington over who would pay for it.

Yesterday the subcommittee was told the Navy would begin work on the survey but that unless it received an additional $2.4 million by Aug. 1, the project would not take place.

Appropriations Suncommittee on Interior Chairman Sydney R. Yates (D-Ill.) asked officials from the Interior Department if they were going to come up with the money and was told a decision had not yet been made.

Tests are also being done on the cocoanuts and other food products grown on Enyu to see if radioactivity in the soil is being taken up in the food.

Ruth Van Cleve, director of Interior's Office of Territorial Affairs, said Enyu "was likely to be a safe site."

She said her office was seeking $6 million this year out of a total of $15 million designated to resettle the entire Bikini group somewhere other than Bikini Island.

A final determination about the safety of Enyu would be made by Jan. 1, Yates was told.

If this month's medical tests of the current Bikini residents show their strontium level has not increased, the witnesses agreed it would be safe for them to continue living where they are until next year - provided they eat only imported food.

"Look for alternatives, just in case," was Yates' suggestion to the Interior Department officials.