A little-noticed announcement by Pennsylvania environmental officials supports some of Virginia officials' worst fears about the likely persistence of the pesticide Kepone in the state's waters.

The announcement Feb. 7 said that fish in a stream near a central Pennsylvania plant that produced Kepone 13 years ago had been discovered with significant amounts of Kepone in their bodies. In addition, "significant quantities" of Kepone and Mirex, a closely related pesticide, had been found in soil near the plant and probably will have to be destroyed, the Pennsylvania officials said.

Assistant Virginia Health Commissioner Dr. Robert S. Jackson said today that the Pennsylvania findings tend to support fears of Virginia officials that portions of the James River may have to remain closed to fishing "for some period of time" because of Kepone pollution.

About 100 miles of the river from Richmond to Hampton Roads was closed to fishing interests last December by Gov. Mills E. Godwin after high levels of the pesticide were discovered in fish taken from the river. At the time of the trial of Allied Chemical Corp., which was convicted of secretly dumping the pesticide into the river from its Hopewell plant, state officials estimated that the pesticide would remain in the river for decades.

Disclosure of the Pennyslvania findings comes at a time when an Environment Protection Agency panel is considering easing a standard for allowing sale of Kepone-contaminated fish in interstate commerce. Currently fish with .1 parts per million or less of Kepone in their bodies are allowed to be sold. Virginia officials and seafood interests are pressing for a standard of .3 parts per million of Kepone, triple the current amount allowed.

In Pennsylvania, trout and suckers with more Kepone than the federal government currently allows in commerical fish were found in Spring Creek, a central Pennsylvania stream described as "an important and heavily used trout fishery." The Kepone in the stream apparently came from a Nease Chemical Co. plant near State College, Pa., which made Kepone for Allied from April, 1958 to August, 1959, and from March, 1963, to August, 1963.

Unlike Virginia, where about 75 former chemical workers who made Kepone have been diagnosed as ill from Kepone poisoning, no such incidents have been reported in Pennsylvania. But the Pennsylvania Fish Commission has cautioned residents near the stream that fish taken from creek "should be consumed only on an occasional basis as a precautionary measure."

Jackson, the Virginia health commissioner, said the Pennsylvania study indicates how Kepone apparently is recycled by fish in their environment and persists long after the source of the pesticide is removed.