A drop in the estimated enrollment of Prince George's County schools next year has prompted School Superintendent Edward G. Feeney to cut an additional 109 teachers and over $1.7 million from his proposed $271 million budget.

The additional reduction in teachers raises the total proposed staff reduction in the school budget for next year to 283 and the total reduction in teachers to 232, according to board figures. School officials told the board last night the reduction was made possible by a drop of 2,217 in the estimated enrollment of county schools next year.

School officials were unsure whether the additional reduction in teachers could be made through retirements and attrition, as originally had been planned. Asked if the reduction could be done without firing teachers, school spokesman John Aubuchon had a one-word response: "Hopefully."

Aubuchon explained that normally about 400 of the schools' 7,000 teachers leave the system through attrition each year. "But we sometimes have problems shifting teachers into the right slots to avoid firings," Aubuchon said.

"I'm very disturbed by this," said Toby Rich, the president of the Prince George's County Education Association, which represents teachers. "It seems like they are putting the whole weight on one shoulder -- why aren't they cutting any administrators or staff secretaries if enrollment has declined this much?

"I think they may be sending up a trial balloon to see who gets upset over this," Rich said.

The projected drop in enrollment is a result of a new enrollment analysis completed by school officials after they received the enrollment figures for this year as of Sept. 30. The projected decline means that total enrollment in Prince George's schools would drop from 133,613 this year to 127,415. Since 1977, according to the board's figures, total enrollment in the schools will have declined by more than 11,000 as of next year.

"Our budget started being put together before the returns on enrollment were really in," said Elliott Robertson, the schools' budget superintendent. 'We had to go to press with something but when the Sept. 30 figures came in we had to reanalyze where we were."