SEMIPALATINSK, KAZAKHSTAN -- It was the happiest day of Sergei Davydov's life: Aug. 29, 1949. The retired engineer still remembers the blinding flash and his "feverish joy" at the sight of a huge, mushroom-shaped cloud erupting over the desert of northern Kazakhstan. The Soviet Union, the world's first communist state, had become a nuclear superpower -- and he had pressed the button.

In a squalid wooden hut 600 miles away in southern Russia, by the bank of the Techa River, Mavzhida Valeyeva remembers 1949 for a different reason. It was the year her health began to deteriorate dramatically. Along with practically all her neighbors, she now suffers from violent headaches and constant nosebleeds. Her blood is anemic. Her four children and five surviving grandchildren are all invalids.

It took Valeyeva more than four decades to make a connection between her family's devastating health problems and the Soviet Union's nuclear bomb project. In 1990, the Soviet government finally acknowledged that millions of tons of highly toxic radioactive waste had been secretly dumped in the Techa by a plutonium plant 49 miles upstream from Valeyeva's village, Muslyumovo. The river the villagers saw as a source of life was in fact a source of death.

"It would be better if they had never discovered this nuclear energy," said Valeyeva, who visited the river daily to collect drinking water and wash her family's clothes. "It would be better to be poorer, but at least to be healthy and give our children and grandchildren a chance of living a normal life."

The communist politicians who launched the Soviet Union on a program of breakneck industrialization and transformed the country into a military and political rival of the United States, believed that the natural resources under their control were inexhaustible. Yet future generations of Russians and Tatars, Balts and Ukrainians, Czechs and Poles will pay a heavy price for the hubris of their leaders. There came a point when nature simply rebelled.

Based on a two-month journey from the center of Europe to the Russian Far East, this is the third in a series of articles about the legacy of Marx, Engels, Lenin and Stalin. Today's article looks at the destructive impact that communism had on the environment in Russia -- one of the scars left by the combination of totalitarian rule and socialist economics that will almost certainly take generations to heal.

The environmental catastrophe left behind by 70 years of communist rule is visible in poisoned rivers, devastated forests, dried-up lakes and smog-polluted cities. Some of these disasters, such as the evaporation of the Aral Sea following the diversion of rivers for an irrigation project, have permanently changed the contours of the vast Eurasian landmass. But, according to Russian scientists and ecologists, the most lasting physical damage will probably have been caused by the unleashing of nuclear power.

"Radioactive contamination is the number one environmental problem in this country. Air and water pollution come next," said Alexei Yablokov, a biologist who serves as President Boris Yeltsin's chief adviser on environmental matters. "The way we have dealt with the whole issue of nuclear power, and particularly the problem of nuclear waste, was irresponsible and immoral."

The scale of nuclear contamination in the former Soviet Union has only become clear over the last few years, with the advent of free speech and the lifting of censorship restrictions. In the wake of the 1986 Chernobyl catastrophe, Russians learned about other disasters, including a series of accidents at a plutonium-producing plant near the southern Urals city of Chelyabinsk between 1948 and 1967. They also learned about dozens of ad hoc nuclear dumps, some of which could begin seeping radioactivity at any moment.

The seas around Russia -- from the Baltic to the Pacific -- are littered with decaying hulks of nuclear submarines and rusting metal containers with tens of millions of tons of nuclear waste. Russia itself is dotted with dozens of once secret cities with names like Chelyabinsk-70, Tomsk-7 and Krasnoyarsk-26, where nuclear materials have been stockpiled. Unmarked on any map, they hit the headlines only when there is an accident. Vast areas of the country have been treated as a nuclear dump, the result of four decades of testing.

"We were turned into human guinea pigs for these experiments," said Bakhit Tumyenova, a senior health official in the Semipalatinsk region, the main Soviet nuclear test site until 1989. "They kept on telling us that it was for the good of the people, the Communist Party, the future. The individual never counted for anything in this system."

'A Pernicious Philosophy'

The testing of the Soviet Union's first atomic bomb in 1949 represented a huge achievement for a backward, semi-Asiatic country. It had mobilized vast economic and human resources, from the team of elite scientists who designed the bomb to the army of slave laborers who mined the uranium and disposed of the nuclear waste.

The two sides of the Soviet nuclear project -- the epic achievements and the disregard for human life -- are symbolized by the man initially in charge of it. Lavrenti Beria, the chief of Stalin's secret police, was a great organizer. But he was also a great destroyer, willing to obliterate any obstacle to achieve his goal.

"It was a heroic epoch," recalled Igor Golovin, a leading scientist and biographer of Igor Kurchatov, the head of the nuclear project. "We worked days and nights and really believed in what we were doing. The propaganda instilled the idea that the United States had the bomb and wanted to enslave us, so it was vital that we acquired our own nuclear weapons as soon as possible, whatever the cost."

Few of the scientists and engineers working on the project gave much thought to the dangers of radioactive fallout. After pushing the button that triggered the first nuclear device, Davydov rushed to the site of the explosion without any protective clothing or gas mask. He was later sick with leukemia for some 20 years.

"They gave me special injections, and it somehow stabilized. Now I feel all right," said the 76-year-old pensioner, proudly displaying a chestful of medals. "Personally, I think that all those people who demand privileges from the government because their health suffered as a result of these tests are just crooks and swindlers."

The idea that any sacrifice was justified in the effort to turn the Soviet Union into a superpower was a fundamental part of the communist ethos. ("You can't make an omelette without cracking eggs," Lenin liked to remark.) It permeated the nuclear project right from the start, and still exists to some extent among older people. The system elevated the state above ordinary individuals -- and this was its basic flaw.

"The postwar generation was brought up with the idea that they should be ready to sacrifice themselves for the state. This was the philosophy of the time. It was a pernicious philosophy because it prevented any thought being given to ecological problems," said Natalya Mironova, an environmental activist in Chelyabinsk. "For many years we were unable even to discuss such matters."

Little attention was paid to such issues as nuclear safety and the training of responsible personnel. The manager of the Chernobyl plant at the time of the 1986 disaster had previously been in charge of a heating plant. According to officials, roughly 50 percent of the accidents in nuclear power stations and 75 percent of accidents on nuclear submarines are due to "human error."

This year alone, there have been at least three accidents at nuclear facilities in Russia involving the release of radioactivity. The government has been inundated with dozens of letters from scientists at both military and civilian nuclear facilities warning of "further Chernobyls" because of rapidly deteriorating working conditions and the departure of many highly qualified workers.

Into the Food Chain

For the 1,000 inhabitants of Muslyumovo in the southern Urals, the Soviet Union's experiments with the atom are a curse that will blight the lives of many generations. According to the local doctor, Gulfarida Galimova, four of every five villagers are "chronically sick." She says the effects of radiation have altered the genetic code of the local Tatar population, with the result that babies are often sick from birth.

"We do not have a future," said Galimova. "We have been so genetically harmed that our descendants will not be able to escape this curse. Patients come to me, and I know I can never cure them. Radiation has entered the food chain. Our cows eat radiated grass. The potatoes we grow in our back yards are poisoned. The only solution is to close this entire region off -- and not let anyone come here for 3,000 years. But they won't do that, because there isn't enough money."

The 2.75 million curies of radioactive waste flushed into the shallow Techa was equivalent to half the fallout from the bomb that fell on Hiroshima, but nobody bothered to inform local inhabitants. In the late 1950s, signs were posted along the Techa warning people not to bathe in the river. The nature of the danger was never explained, so most villagers paid little attention.

In the early 1980s, Galimova first started noticing that something was terribly amiss with the health of Muslyumovo residents. Nearly 10 percent of births in the village were premature. Many of her patients were anemic. There was a high incidence of cancer. When she reported her findings to her superiors in Chelyabinsk, the problems were blamed on bad food and a lack of hemoglobin. She was accused of being a bad doctor.

What local people refer to as "the river illness" is now affecting the third and even fourth generation of Muslyumovo residents. Valeyeva's eldest son, Ural, 33, is mentally retarded. His three children -- aged 6, 4 and 18 months -- can barely summon up the energy to get out of bed. Another daughter, Sazhida, 29, has a chronic craving for chalk that has destroyed all her teeth. Her oldest son, Vadim, 11, has been sick from birth. Timur, 6, has chronic bronchitis and anemia.

It was not until April 1986 that Galimova finally guessed what was the matter. Chernobyl played a crucial role in convincing Mikhail Gorbachev and other Soviet leaders that the country's problems could not be solved without glasnost, openness. Discussion of ecological problems was no longer taboo.

When they finally came clean about the contamination of the Techa, the authorities also admitted two disasters involving the Mayak plutonium-producing plant at Kyshtym, some 60 miles northwest of Chelyabinsk. In 1957, a waste storage tank exploded at the plant, releasing 20 million curies of radiation. A decade later, a drought dried up nearby Lake Karachai, which had been used as a storage tank for 120 million curies of waste products from Mayak. High winds scattered radioactive dust over a wide area.

According to an official Russian government report released earlier this year, the three disasters at Mayak affected 450,000 people living in a contaminated region roughly the size of Maryland. The amount of radioactivity still stored at Mayak -- much of it in insecure conditions -- is equivalent to the fallout from 20 Chernobyl disasters.

Nearly 20,000 residents of the Chelyabinsk region were evacuated from their homes. By a tragic twist of fate, some of these people were moved from one high-risk region to another.

Valentina Lazareva, for example, was evacuated from a village near Mayak in 1957 as a 9-year-old orphan. There were rumors of an "explosion" at the plant, but nobody knew anything for sure. She spent the rest of her childhood in an orphanage in Brodokalmak, a village a few miles downriver from Muslyumovo. The children crossed the Techa every day on their way to school and drank water from a nearby well. In the summer, they would swim in the village.

"Now we are all sick," said Lazareva, who is 46 but looks much older. "There were 32 people in my class. We have already buried five of my classmates. Another 10 are dying. But all are invalids, in one way or another."

Glasnost Without Rubles

Today, there is no shortage of glasnost about the man-made environmental disaster confronting the former Soviet Union. But there is a desperate shortage of resources to do much about it. The amount of money the government has earmarked to clean up the Chelyabinsk region -- roughly $20 million -- is minuscule compared to the $40 billion to $60 billion cost the United States has projected for the cleanup of its main plutonium-producing facility, the Hanford nuclear reservation in Washington state.

In Kazakhstan, which declared itself an independent state in December 1991 following the breakup of the Soviet Union, health officials say they are unable to provide even basic medical care to villages exposed to four decades of nuclear tests. The lack of basic health services has encouraged many people to turn to charlatans and faith healers for help. In Semipalatinsk -- the site of 470 nuclear explosions, including 116 in the atmosphere, between 1949 and 1989 -- a Muslim preacher named Sary-Aulie has been attracting crowds of 10,000 with his promise to cure aches and pains through "vibrations."

"We can't do much for these people, so it's not surprising that they put their trust in charlatans," said Tumyenova, the regional health administrator. "The Semipalatinsk test site served the entire Soviet Union. Now the other republics have gone their own way -- and we have been left alone, sitting on top of a gigantic nuclear rubbish heap."