Debra Seddon, 18, who recently returned from helping artist Christo "wrap" an island off the coast of Florida, is sculpting clay zebras and elephants, using residents of the National Zoo as models.

Kevin A. Berlin, 18, will spend the summer painting and designing collages at the Corcoran School of Art, reading philosophy, listening to Beethoven and "seeing as many movies as I can."

And Rachel Pastan, 18, is hard at work on a short story about death and nuclear destruction.

The three Montgomery County high school students are among 141 students nationwide to receive the $1,000 Presidential Scholars award--and among 20 in the nation chosen for their artistic skills. The honor is given to students who demonstrate "the finest qualities in American education," according to the congratulatory mailgram each recently received from the White House.

Six Maryland high school students were chosen for the award, the largest contingent of winners ever from the state. President Reagan will present the students with medallions during a reception on the South Lawn of the White House June 16.

Seddon, who is graduating from Richard Montgomery High School, spent half-days during her senior year at Albert Einstein High School, where a special arts program was given. She had a B average, she said, and was one of five visual arts finalists for the scholarship.

She will attend Carnegie-Mellon University in Pittsburgh. "They have an excellent fine arts program. They teach glass-blowing, and that really sounds interesting," she said.

Pastan said she was "more or less" a straight-A student at Sidwell Friends School in the District, where her extracurricular activities included work on the literary magazine and playing a fairy in "A Midsummer Night's Dream." She'll put her award money toward expenses at Harvard University.

Her current writing project is "pure fiction," she said. It is also her "first attempt at being political . . . . I don't know that Ronald Reagan would like it."

Berlin will give a speech at his graduation from Walt Whitman High School in Bethesda and said he planned to use the story behind the song "Amazing Grace" as his topic. "The message is people should never be afraid to do anything they believe is right," he said. "If you can't do it for yourself, you can't do it for the world either."

Berlin will attend Yale University in the fall and will study painting and, eventually, he hopes, film directing.

The three other Maryland award winners are from the Baltimore area and were selected on the basis of academic achievement. They are Wendy Leng of Dulaney High School in Cockeysville, Ronald G. Dove of Bel Air High School and Anne M. Lopez of John Carroll High School in Bel Air.

Students were selected for the awards by the Department of Education's Commission on Presidential Scholars, a volunteer group named by the president.

Each year 1,000 applications are sent to high school seniors who have high scores on standard college entrance exams or have participated in the Arts Recognition and Talent Search, a national program that identifies exceptional students in the arts. Those who are interested must write a biographical essay and, for academic scholars, two others on topics ranging from "The Immortality of Mozart" to "Law and Human Freedom." Academic and nonacademic achievements are then evaluated by a citizen panel, which selects two scholars from each state and 15 at large, two from U.S. families abroad and 20 in the arts.