The recent arrest of a Hebrew teacher here, climaxing a series of official actions against teachers and students of Hebrew, have awakened fears among Jewish activists that the new Soviet leadership could take further measures.

Vladimir Livshitz, who is also a computer specialist, was arrested early this month at his work place, according to western diplomats and Soviet sources.

Livshitz is expected to stand trial later this month, apparently on charges related to his activity in the Jewish community. He was involved in defense efforts for a Jew arrested last June and eventually sentenced to three years in jail for "anti-Soviet slander."

Livshitz's arrest was the first of a Jewish activist here in several months. It dampened expectations growing out of the U.S.-Soviet summit last November that local authorities would loosen restrictions on the Jewish community and break the logjam in applications to emigrate.

*The Washington office of the National Conference on Soviet Jewry estimated that several thousand of Leningrad's Jews, which it put at up to 200,000 in a population of almost 5 million, have been refused permission to emigrate.

The signals sent to Jews here, including those who seek to emigrate, have been mixed.

Many said they were shocked by an article in the official Leningrad Pravda newspaper that linked study of the Hebrew language with anti-Soviet behavior. Western diplomats said the link had never been made directly before, despite occasional waves of harassment, arrests and beatings of Hebrew teachers and students in the period after detente, when the permission for exit visas fell dramatically.

The article, entitled "The Dirty Hands of Provocateurs," detailed several cases of American tourists and other visitors from the West bringing in literature, clothes and gifts for Soviets and warned local citizens against contact with such foreigners. It identified by name several local individuals it said were actively involved in studying Hebrew.

This followed harassment of several young Soviets who had inquired about the possibilities of learning Hebrew in Leningrad.

The general effect of the actions and the article, according to several members of the community and western diplomats familiar with it, was to discourage Hebrew students.

"Clearly," said one western diplomat, "the decision has been made to isolate Hebrew students and teachers by particularly harsh treatment."

But in the past month, several longtime Leningrad refusedniks were given permission to emigrate, and others learned that they would be allowed to join their families in the United States.