BRZOZKA, POLAND -- Perhaps the purest of Polish pleasures is to meander through a leaf-carpeted forest on a crisp autumn morning and pick mushrooms that are not poisonous.

"I can rest here in the forest. I can have my beautiful, clean walk. Most of all, for me, there is the pleasure of the act of pulling mushrooms out of the ground," said Zbigniew Orczyk, a water engineer from central Poland who was taking a two-week mushroom leave here near the German border.

Mushrooming, for Orczyk and millions of his countrymen, is a culturally sanctified respite from the polluted drabness of urban life. Besides pristine air and the crunch of leaves underfoot, there is the gustatory allure of wild mushrooms. Poles love them, whether freshly fried, dried or boiled. They use them in all manner of soups, sauces and the traditional Christmas pirogi.

On any clear fall day, the shoulders of highways that cut through Polish forests are crowded with private cars and buses. Companies organize day excursions to the woods. At dawn, vehicles disgorge workers -- men and women -- who scamper away on the spongy forest grass, empty mushroom buckets in hand, cheeks pink with the cold.

Later, after buckets have been filled, there are long, flirtatious lunches with sausage sandwiches, fresh apples and multiple snorts of vodka. Marriages have been sealed, children have been conceived, divorces have been instituted -- all byproducts of a day's mushrooming.

These outings have been immortalized in Polish films and television programs. Popular songs celebrate the virtues of mushrooms. The fleshy fungi have insinuated themselves into the language. To assert that someone is as healthy as a mushroom is to say that one is the picture of radiant health.

There are, unfortunately, two decided downsides to this Polish passion: poison and radiation.

This year, as is common yearly, 200 Poles became violently ill and died after eating poisonous forest mushrooms. In one week last month, seven children in southern Poland died from mushroom poisoning.

Part of the poison problem is that one large, handsome, particularly tasty wild mushroom that Poles call prawdziwek happens to look very much like a particularly lethal mushroom known as Szatan or Satan.

Experienced pickers have two methods for keeping szatan out of their soup. "If I have a doubt, I touch the mushroom with my tongue," said Orczyk. A bitter, poisonous taste is what he hopes not to experience. "Also the worms know. If there are worms crawling around a mushroom, then it must not be poisonous."

Neither the tip of the tongue nor wise worms, however, can alert a Polish picker to a mushroom chock full of radioactive cesium.

Since the Chernobyl nuclear accident in the Soviet Union in 1986, the average level of radioactivity in the Polish environment has increased more than threefold, according to Jan Jagielak of the Central Radiological Protection Laboratory in Warsaw.

Of all the foods eaten in this country, Jagielak says, wild forest mushrooms are by far the most contaminated by radiation. Compared to Polish milk, the level of measurable radiation in wild mushrooms is 100 times higher.

Warnings against eating too many wild mushrooms are frequently issued over Polish radio. Children are advised not to eat any. Jagielak said recently that the relatively small amount of wild mushrooms eaten by most Poles would probably not cause radiation poisoning.

Among the pickers here in the forest near Brzozka, radiation is a concern, but only in the abstract.

"A bucket per person per year -- we do not think this is so harmful," explained Zdzislaw Morawski, manager of a food processing plant in southern Poland who led a company outing to the forest here.

Morawski and his employees, four men and a woman, lounged on blankets on the forest floor, surrounded by fallen leaves and brimming buckets of mushrooms. They looked bleary-eyed but happy.

At 2 a.m. the previous morning they had left their hometown of Dzierzoniow, about 155 miles to the south. They drove all night, picked mushrooms all morning and at noon were lingering over lunch, putting off the long drive home.

"First of all, it is relaxing," said Morawski. "It is not every day that we do this. We look forward all year to the open air. We get mushrooms for the Christmas pirogi. I say it is better than watching TV."