As boom times fade, Europe struggles to absorb 9 million immigrants

* Hans Janmaat recently became the first avowed fascist candidate to be elected to the Dutch parliament since World War II.

* In neighboring West Germany, Chancellor Helmut Kohl made a point in his first leadership declarations to state that he would try to resolve the problem represented by the presence of some 5 million foreigners.

* And anti-immigrant positions, declarations, and pamphlets figured prominently in the Belgian municipal election campaign that ended last week.

These recent examples of Western European unrest over the estimated 9 million foreign workers and their families in their midst, are only the latest in a long string of such episodes.

There have been bloody riots with racial undertones in recent months in the Brixton section of London; fights between rampaging teen-age gangs of Turkish immigrants and local skinheads in Stockholm; and openly anti-immigrant campaign oratory by the French Communist Party in the 1981 presidential elections.

Other expressions of concern at the international level have also surfaced in recent months from the International Labor Organization (ILO), which warned of ''the time bomb'' in Western Europe represented by millions of young immigrant children facing even greater problems of integration and employment.

Confronted with this potentially explosive problem of millions of foreigners imported during the economic boom years of the 1960s, European governments have reacted in different ways.

Most have sought to block new arrivals and even to stimulate a reverse flow of departures through means ranging from financial repatriation bonuses to outright expulsion. Faced with rising unemployment, virtually all governments have sought severe curbs on new entries.

Such policies have strained relations between the host countries of Northern Europe and the traditional manpower exporters around the rim of the Mediterranean. It has become a source of some friction between the nations in the European Community (EC) and the new or candidate states of Greece, Spain, and Portugal over the Community's existing laws promising free movement for its citizens throughout the territory.

According to EC statistics, there are at least some 700,000 Turks in the member countries, nearly 500,000 Portuguese, more than 400,000 Yugoslavs, 360, 000 Algerians, 350,000 Spaniards, 270,000 Moroccans, and nearly 100,000 Tunisians. West Germany accounts for about 2 million foreign workers; Britain and France, about 1.6 million each.

But these numbers are considered low and do not account for the thousands of unregistered foreigners. Other countries such as Greece, with an estimated 750, 000 Arabs, and Italy, with about 400,000 Arabs, have significant foreign populations as well. In the 10 EC countries, it is estimated that 7.3 percent of the population is foreign, with a high of 36 percent of the total population in Luxembourg.

The presence of these large foreign communities, in which unemployment is often higher than the already-record rates in the host countries, puts additional strains on welfare budgets and on relationships with the local population.

During a recent West German Bundestag debate on the subject, a Christian Democratic member, Albert Dregger, warned that millions of additional Turkish immigrants stood poised to enter West Germany in the coming years. ''When that tide engulfs us, it would mean the collapse of our welfare state,'' he said. During the Belgian local election campaign, an ''open letter to the rabble'' circulated, advising immigrants that Brussels ''will never be your Chicago, your jungle, or your casbah.'''

But in addition to trying to limit the growth of the foreign population, most European countries have moved to defuse the ILO's threatened ''time bomb'' of uprooted foreign youths.

They have set up special classes in Turkish, Arabic, the Koran, or other ethnic subjects to help these second-generation immigrants, some of whom have never seen the country of their parents, acquire a familiarity with their language and culture. But a visit to the cafes and communities that are the homes of these young foreigners reveals a tense atmosphere of ethnic gang clashes, generation gaps, and resentment.

Talking about his daily walk to and from school through sometimes hostile ''turf'' a Turkish teen-ager in Brussels quipped: ''Every day I have to go through Morocco, Algeria, Tunisia, Italy, and Spain - just to get to school.''