Editor's note: The following article appeared in the May 26, 1986 issue of DER SPIEGEL, just days after the world became aware of the Chernobyl nuclear disaster. During the next few weeks, SPIEGEL ONLINE will publish a series of reports on the worst accident in the history of civilian nuclear energy and how it changed Europe and the world.
The diggers came from Kiev. Four hundred workers normally responsible for subway construction in the Ukrainian capital are busy furrowing their way through the ground under Chernobyl. They're building a reinforced concrete tunnel, several hundred feet long that will eventually reach beneath the reactor complex. Only in this way -- or by flying 100 meters above the ground in helicopters -- can people approach the reactor site, even four weeks after the disaster.
The digging of the tunnel and the construction of an enormous steel "sarcophagus" to encase the molten reactor core are only the beginning of a century-long project. The man-made radiation source, which generates new heat continuously, will have to be cooled and carefully watched for generations -- an historically unprecedented situation.
The Lawrence Livermore National Laboratory in California has provided the first relatively precise estimates of the amount of radioactivity released by the Chernobyl disaster. The scientists at the laboratory are specialists; for decades they've worked on the construction of nuclear bombs and on ways to calculate nuclear fallout.
According to Joseph Knox, head of the Laboratory's Fallout Warning Center, this particular emission was "mammoth." The reactor core contained roughly 80 million curies of iodine 131 and 6 million curies of caesium 137, a "large part" of which was released into the atmosphere. By comparison, only 15 curies of radiation were released during the reactor meltdown at Pennsylvania's Three Mile Island plant in 1979.
Scientists at the Lawrence Livermore Laboratory have produced a macabre series of graphics with the help of the US Air Force's worldwide weather service: they show how radioactive clouds spread through the northern hemisphere during the first ten days after the catastrophe.
Ground measurements confirm that of all the Western nations hit by the toxic Chernobyl cloud, Finland and parts of Sweden were most severely affected. They were the first non-Eastern European countries reached by the cloud. But if fear could be measured in curies, then the country most seriously affected would be Germany.
True, federal and regional authorities claimed last week that the risks posed by radiation in Germany had decreased, and revoked their warning against eating spinach and lettuce. Children were allowed to play outside again.
No one is touching the salad
But no one is touching the salad buffets in the country's steakhouses. Some scientists, including those at Hanover's Ecological Institute and at the University of Oldenburg, are warning against drinking milk again. The term "radiation-free" has become part of advertisements for fresh vegetables, like the one used by Dutch farmers. "Consumption is slowly rising," the newspaper Hamburger Abendblatt informed us last week, referring to the fruit and vegetable markets.
Politicians tried desperately to jump on the bandwagon of the new anti-nuclear sentiment. Electoral candidate Ernst Albrecht discovered his love for solar energy, announcing the creation of an institute devoted to solar technology, and the general secretary of the Free Democratic Party, Helmut Haussmann, did a 180° turn by declaring that the German nuclear reactor in the western German town of Kalkar was unnecessary.
Research institutes and phone lines received fewer calls from worried citizens last week, but discussion forums featuring qualified scientists continue to be well attended. But the general confusion -- consisting of warnings and reassurances, measurements and opinions -- persists.
Was it right to just plough over radioactively contaminated lettuce and spinach? "Farmers should plough over and re-fertilize their fields," declared Lower Saxony's Ministry of Agriculture. But Dr. Heinz Helmers, a professor of physics in Oldenburg, argued that ploughing over the fields would just cause radiation to move further underground, so that it would enter the food chain via the roots of plants. His advice: cut the stalks of plants and deposit them on a piece of foil, then remove the topmost layer of earth in every garden. And where should we put it? No one knows.
Other scientists, such as physicists at the University of Constance, merely served to aggravate the confusion. Professor Ekkehard Recknagel advised farmers to mow the grass on their pastures, let it dry and then deposit it in junkyards. Only two days earlier, the professor had spoken on regional television and recommended ploughing over pastures. Two days later, scientists from Recknagel's department also told the regional government the grass needed to be mowed.
But there was no way farmers could have followed the advice anyway. One hectare (2.5 acres) of grazing land yields eight tons of grass, a farmer from the region of Lake Constance explains. Not only does he not know how to get rid of such a large amount of grass, but he needs it to feed his livestock too. "We're going to have the caesium in our food for years," says another desperate farmer from Hanover.
That's also little more than hearsay. All claims about the effects of radiation on the food chain -- whether short, medium or long-term -- remain "provisional and highly imprecise," US physicists Thomas B. Cochran and Frank von Hippel explain. The nuclear physicists at Hanover's Ecology Group agree: "Overhasty claims are a bad idea. Reliable measurements will only be available in two to three months."
No end of advice -- but can it be trusted?
There was no end to the pre-fabricated advice available last week. Some of the better news comes from Lower Saxony:
--The levels of iodine in vegetables have decreased. Twelve weeks after the arrival of the cloud from Chernobyl (that is, towards the end of July), the iodine 131 will effectively have disappeared (due to its relatively brief half-life of 8.04 days).
--Fish can be safely consumed. This is the result of examinations conducted on pond fish, but also on plaice and herring from the North Sea.
--Only very low levels of radiation have been detected in mother's milk. Drinking water has not been affected.
Scientists continue to be divided over the question of whether wild game can be safely eaten. The Agricultural Ministry of Lower Saxony announced: "We shot 12 deer and found nothing. Only the innards should be avoided." But Saarland's regional government makes a very different claim: that the examination of roadkill has revealed high levels of radiation -- 207 Becquerel of iodine 131 and 187 Becquerel of caesium 137 per kilogram of meat.
Saarland's Economics Minister, Hajo Hoffmann, recommended postponing the hunting season for as long as possible. The region's Hunters' Association then advised its members "to kill the minimum number of deer and then deep-freeze the meat for about three to four weeks." More nonsense. "Neither deep-freezing nor cooking the meat has any effect on isotopes such as caesium and strontium," says Professor Recknagel of the University of Constance.
The Heidelberg Institute for Energy and the Environment, highly respected among ecologists, has provided estimates on the presence of caesium 137 in foodstuffs, based on government data. The results:
--According to a measurement taken by Baden-Württemberg's Ministry of the Environment on May 15, the average level of caesium in 21 samples of grass was 681 Becquerel per kilogram. An increase in the level of caesium in beef is to be expected, as cattle are once more being allowed to graze on contaminated land. Red deer and wild boars should be avoided, as they retain caesium up to 20 times more effectively than domestic stock.
--There are as yet no measurements for fish in Baden-Württemberg, but high levels of caesium in fish from affected lake regions are probable.
--Mushrooms and berries should be avoided. Mushrooms retain caesium ten to 15 times as effectively as other plants.
--Turnips, asparagus, potatoes and grains can be safely consumed.
Dr. Wilhelm Steffens from the Institute for Radioagronomy at the Nuclear Research Institute in Jülich explains why crops from the summer of 1986 will hardly be affected: most of the radioactive fallout, mainly iodine 131, will have decomposed by harvesting time. Caesium 137 and strontium 90 will remain in the topmost layer of the earth, no deeper than two to three centimeters (0.8-1.2 inches); they will therefore be "unreachable for most plant roots."
The two substances will reach the "root zone" only if the earth is ploughed, Steffens explains. But ploughing also dilutes the overall concentration of these substances. "Radioactivity from caesium and strontium is transferred to plants only very slowly, because both substances are retained by clay and humus particles in the earth."
In one year, only five percent of the caesium spread by rain and ploughing is likely to be taken up by plant roots, according to Munich's Society for Radiation and Environment. The rate of absorption can be decreased further by using fertilizer rich in calcium and potassium.
Nevertheless, both caesium 137 and strontium 90 -- present in "surprisingly low quantitites," according to the journal Nature -- will make its way into the food chain. Measurable quantities will soon be found in virtually all foodstuffs: plants, mammals, birds and fish. "It will take some time before we return to the levels we had before Chernobyl," says Heide Rieke, spokesperson for Hamburg's environmental authority.
As far as the medium and long-term risks associated with caesium are concerned, there have been optimistic predictions too. Professor Beowulf Glöbel from the Homburg/Saar University Clinic says the caesium 137 released by the Chernobyl disaster will have disappeared from the biosphere within two years. Precipitation will cause the isotopes to be "washed out of" the ground and the plants that grow in it, Glöbel says. Only "a fraction" of these isotopes will enter the food chain. "Every year, the radioactive particles sink into the ground by between one meter and ten meters" (3.3-33 feet).
Despite its long physical life-expectancy (a half-life of 30.1. years), caesium 137 remains in human and animal organisms for a relatively brief time only. The particles are expelled from the body within about 100 days (their "biological half-life"). The question is how long it takes the particles to return to the food chain and how exactly they affect the human organism.
Glöbel, a doctor specializing in radiation treatment, doesn't rule out that "the cancer rate may increase" in the Saar region -- perhaps by 0.1 percent. But it will be difficult to prove that this additional cancer victim per 1,000 inhabitants died because of Chernobyl.
Any attempt by politicians to brush away this medical "residual risk" was pre-empted by Professor Harald Theml, a leukemia specialist in Karlsruhe. "We doctors shouldn't be fooled," he said in an interview with the journal Ärztliche Praxis. Even if the additional cancer cases are likely to "disappear into the statistical background," that doesn't mean the situation is harmless. "Every additional cancer case is a case too many," says Theml, adding that "Every additional millirem of radiation has carcinogenic potential."
Scientists now largely agree on how exactly various kinds of radiation damage the human cell. But the extent of the harm and its long-term effects remain a matter of opinion -- estimates of the number of dead that can be expected after Chernobyl range from 4,000 to several hundreds of thousands.
This uncertainty underlies the agonizingly contradictory claims made by German scientists after the disaster and the ongoing disagreements between scientists and government officials.
One drastic example comes from the city of Kiel, where Professor Helmut Gremmel and Dr. Henning Wendhausen from the Department of Radiology caused a panic by claiming that pregnant mothers, small children and adolescents would have to be specially nourished with food from the southern hemisphere for years. The claim was based on radiation measurements from the 1960s, a period of frequent nuclear testing.
"Let's say we were persuaded."
The scientists revoked their warning on Tuesday of last week, after speaking to Kiel's Social Affairs Minister Ursula von Brockdorf. They explained that their claims "could not be sustained" and that the warning had perhaps been issued "overhastily." When DER SPIEGEL asked about the reasons for this change of position, the reply was: "Let's say we were persuaded to revoke our statement."
Is the government putting pressure on scientists? The truth seems to be that the claim by Gremmel and Wendhausen was based on a miscalculation, as were those of many others. They had equated the measurements taken during the (relatively brief) period before a radioactive cloud disperses with the measurements of radioactive fallout taken throughout the 1960s -- a bit like confusing the precipitation during a rainstorm with the annual average.
"Is it really the case that today's science is biased and instrumentalized?" asked Rhineland Palatinate's Minister for the Environment, Klaus Töpfer, on Thursday of last week. "Is science becoming a weapon in party-political disputes?" Do the names of scientists now have to be supplemented with epithets such as "ecologically minded" or "pro-nuclear," like those of politicians?
West German scientists agree on two fundamental points: that a disaster such as Chernobyl has devastating consequences for the country where it occurs, and that three or four Chernobyl-like disasters in Germany would mean radiation sickness and death for the nation, even if the accidents occurred 1,300 kilometers (808 miles) apart.
The inhabitants of the Pacific island of Rongelap were exposed to a radiation dosis of 175 rem when the H-bomb was tested on the Bikini Islands. All 64 inhabitants of the island suffered radiation poisoning. Thirty-one years later, measurements show that coconuts and other foodstuffs grown there are still so strongly contaminated that they cannot be safely consumed.