The explosions at the Semipalatinsk test site stopped several decades ago, but scientists have not fully figured out the extent of the effects of radiation on health. Doctors observing the population of areas adjacent to the landfill still find it difficult to determine the true extent of the harm that long-term exposure to low doses of radiation has done to their health.
The paint on the statues of Lenin has peeled off, some of them are even painted with graffiti, but all still stand in their places in the parks of Semey (until 2007, the city of Semipalatinsk, - ed.) - a small industrial city hidden in the steppes of northeastern Kazakhstan … Kinky cars and buses from the Soviet era - relics of the previous regime - scurry along the streets, past brick high-rise buildings and cracked sidewalks.
Other traces of the past are harder to see. But the legacy of the Cold War is embedded in the history of the city, entered into the very DNA of its inhabitants. The Semipalatinsk test site, located about 150 kilometers west of Semey, was the crucible where the Soviet Union forged its nuclear arsenal. Between 1949 and 1963, the Soviets conducted over 110 ground-based nuclear tests in an area of 18,500 square kilometers. According to Kazakh doctors, up to one and a half million people were exposed to radioactive fallout. Underground tests continued until 1989.
The atomic explosions that razed the Japanese cities of Hiroshima and Nagasaki, or the Chernobyl disaster in Ukraine, have helped accumulate knowledge about radiation sickness. From these tragic events, we have learned grim lessons about the high-intensity exposure to radiation and its long-term health effects on those exposed. However, there was little evidence to show that health effects are passed down from generation to generation.
People living near the test site have been exposed for decades not only to strong explosions, but also to small doses of radiation. Kazakhstani scientists are collecting data on those who survived the explosions, as well as on their children and grandchildren. The consequences are far from always transparent and easy to trace. But recently, researchers have identified an implicit lesion that persists even 30 years after the site was closed. In particular, it was possible to identify an increased risk of cancer, and one of the works published last year suggests that the effects of radiation on the cardiovascular system can be transmitted from generation to generation.
Based on scientific data, Kazakhstani scientists are constantly faced with the fear that has stuck in the minds of people living in the zone of radioactive fallout. Locals tend to blame nuclear tests for all their troubles, although this is not always scientifically confirmed. And for families who still turn to the Kazakh government for medical care, it is important to fully understand the dark past of nuclear testing. This can be helped by the latest genetic technologies, such as next generation sequencing. And by realizing the risks posed by long-term exposure to radiation, Kazakhstani scientists will provide new arguments for the ongoing debate over whether to expand nuclear power to reduce carbon emissions or not.
“The tests at the test site were a great tragedy,” says Talgat Muldagaliev, deputy director of the Research Institute of Radiation Medicine and Ecology in Semey, “but we cannot set the clock back. It remains only to study the consequences."
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Deadly trail
On August 12, 1953, Valentina Nikonchik was playing on the street of Semipalatinsk, when she suddenly heard a deafening explosion, fell down and lost consciousness. So she witnessed the first thermonuclear explosion - it was a second generation nuclear weapon. The explosion released a force equivalent to 400 kilotons of TNT, which is more than 25 times more powerful than the bomb dropped on Hiroshima. In terms of human health, the 1953 nuclear test is considered the most destructive in the history of the test site.
By that time, the Soviet Army had been conducting tests for four years. To study how radiation affects buildings, bridges, vehicles and livestock, bombs were dropped from aircraft and platforms. But the military either did not know that the winds would carry nuclear fallout far across the Kazakh steppe, or they preferred to close their eyes to it. In 1963, representatives of the Soviet Union signed the Partial Test Ban Treaty, and the ground-based explosions stopped. Underground tests, and they lasted until 1989, also carried certain risks, but the first 14 years of tests in the atmosphere are considered the most dangerous in terms of acute exposure.
Absorbed radiation doses are often measured in grays. High doses, starting from 1 heat, lead to cell death and tissue damage. People who are more severely exposed develop radiation sickness, which is accompanied by vomiting, diarrhea, and bleeding. Depending on the intensity of exposure and the degree of cell death, death can occur within a few hours or weeks after exposure. In August 1956, after ground tests, more than 600 residents of the industrial city of Ust-Kamenogorsk were hospitalized with radiation sickness, and it is located almost 400 kilometers east of the test site. There is no exact data on how many citizens died.
The radiation also hits rapidly dividing cells, such as the cells of a developing fetus in the womb. Women living near the test site and exposed to radiation are more likely to have children with chromosomal diseases, including Down's syndrome and congenital pathologies.
In some cases, the effect does not appear for years or even decades. So it happened with Nikonchik. Years after an explosion knocked her down, she developed heart and thyroid problems. She is convinced that this is an echo of trials. “As a child, we never thought about how explosions affected our health,” she recalls.
After a test in August 1956, which led to an outbreak of radiation sickness among residents of Ust-Kamennogorsk, the Soviet military created a top-secret medical clinic for emergency care, where, among other things, they collected data on the health of all exposed. For cover, the military called it "Brucellosis Dispensary No. 4" due to bacterial infection carried by livestock. Patients who sought medical help were examined, but what exactly was wrong with them, they were not told.
In 1991, when Kazakhstan became independent from the Soviet Union, officials from Moscow sent a special commission to Semipalatinsk to declassify the dispensary's information. Some classified data were destroyed on the spot, others were taken with them to Moscow. What they said, modern researchers have no idea. The dispensary was renamed the Research Institute of Radiation Medicine and Ecology (NIIRMiE), and it "inherited" the surviving patient cards. NIIRMiE not only conducts epidemiological studies on how radiation affects human health, but also runs a small clinic for victims of nuclear tests and a mobile first-aid post.
For many years, patients of Dispensary No. 4 and NIIRMiE have been entered into the state medical register in order to monitor the health status of people exposed to radiation. Patients are grouped by generation and dose of radiation, based on their place of residence. Although not all victims were included in the register, at one point it numbered 351,000 people from three generations. More than a third of them have already died, and many others have moved, and the connection has been lost. But, according to Muldagaliyev, about 10 thousand people have been continuously observed since 1962. Scientists believe the registry is an important and underestimated resource for understanding long-term exposure to low doses of radiation and its consequences.
The surviving data came in handy for geneticists to study heredity. In the late 1990s, Kazakh scientists traveled to Beskaragai, a village on the periphery of the landfill that was heavily irradiated. They took blood tests from 40 families from three generations each, and sent them to Yuri Dubrov of the University of Leicester in the UK. Geneticist Dubrova studies how environmental factors affect the so-called germline - that is, the DNA contained in sperm and eggs. The data on families from the outskirts of the test site intrigued him: it will help to identify hereditary mutations.
In 2002, Dubrova and his colleagues found that the frequency of mutations in the germ lines of those directly irradiated was almost twice as high as in the control group. A similar effect was observed in subsequent generations, which the explosions themselves were no longer caught. Their children had a 50% higher germline mutation rate than the control group. Dubrova says if researchers can determine the nature of the mutation in the offspring of irradiated parents, it will predict the long-term health risks of several generations. “This will be the next step,” he says. "We believe techniques such as sequencing can give us a real picture of human mutations and their consequences."
Essence of the question
When Zhanar Mukhamedzhanova was 19, she felt unwell at work. It seemed strange to her, because the work of an accountant is not too laborious, so she went to the regional polyclinic in Semey for examination. The doctors found her blood pressure to be above 160, which is a lot by medical standards. Although Mukhamedzhanova is a city dweller, she spent her childhood in the Abay region near the test site, where one of the highest levels of radiation pollution. Her parents met the trials themselves: her father died of a stroke at 41, and her mother died of heart disease at 70. Older sister Mukhamedzhanova also has hypertension, and her younger sister has heart failure - this is when the heart does not have time to pump enough blood through the body. Although all of these diseases are common in the population, there is some evidence thatthat the incidence among the exposed and their offspring is still higher.
For example, in November last year, Lyudmila Pivina and her colleagues from Semey State Medical University discovered that prolonged exposure to low doses can cause cardiovascular diseases, including high blood pressure. They studied the medical records of about 1,800 people, including the descendants of the irradiated in the second and third generations. When they focused on people whose parents lived in areas that had been exposed to radiation from 1949 to 1989, they found that the risk of hypertension increased in line with the radiation dose received by their parents. They found this discovery astonishing. People whose grandparents have survived the Hiroshima and Nagasaki bombings do not have a similar risk of hereditary cardiovascular disease, said Jim Smith, a radiologist at the University of Portsmouth in the UK.
Perhaps this is due to different ways of influence. With prolonged exposure to low doses, cells tend to accumulate mutations, as they are forced to constantly repair the damage done to their DNA. Bernd Grosche, an epidemiologist, radiologist and former employee of the German Federal Office for Radiation Protection in Oberschleissheim, notes that to understand the full extent of the effects of radiation on human health, it is important to observe all groups of exposed people. According to him, it would be an annoying omission to ignore the data of the Kazakhstani register.
Surveillance of populations exposed to environmental risks is no easy task, however, admits Cari Kitahara, an epidemiological oncologist at the National Cancer Institute in Bethesda, Maryland, who needs to collect detailed data on a large number of people to make a sure conclusion. Kitahara is studying the health effects of radiation on the health of radiologists and radiologists, and is the easiest to track. Her colleagues observe miners from uranium mines and nuclear scientists who are also exposed to small doses of radiation. And if the majority of radiographers are women, and the majority of miners and nuclear scientists are men, then the inhabitants of the irradiated areas near the test site represent the general population.
The study of the effect of radiation on health is hampered by the fact that it is not always possible to write off a specific problem solely on radiation, explains Yulia Semenova, a researcher at Semey State Medical University. She also studies hereditary changes in residents of areas near the test site. Because of the prevalence of cancer and hypertension, cohort studies can help determine the specific factors that contribute to the incidence - when a particular population group is observed for a long time. Semenova and her colleagues, using the registry, plan to develop new epidemiological studies that will help to more accurately establish the relationship between radiation and morbidity.
Doctors observing the population of areas adjacent to the landfill still find it difficult to determine the true scale of the harm that long-term exposure to low doses of radiation has done to their health. And the further, the more difficult it is to distinguish the effects of radiation from the effects of other environmental factors. "Every disaster has a beginning and an end," explains Muldagaliyev, "but in the case of radiation, this end is still unknown."
Invisible consequences
Visitors to the two-story orphanage tucked away in a residential part of Semey are greeted by funny homemade car tire sculptures. On the ground floor, there is a room with creamy orange walls, which the nannies call "sunny." Arthur, a three-year-old boy, crawls on the floor and barely climbs onto a chair. He has already undergone three operations so that he can somehow walk. His older brother was born with hydrocephalus (dropsy of the brain) and for some time he also lived in a shelter, but then he was transferred from here. Two-year-old Maria lies nearby in the cradle. She can neither walk, nor crawl, nor even sit. When she cries, she snorts as if choking. The nannies do not know exactly what is wrong with her and whether she will even live to the age of majority. There are eight children in total in the orphanage.
Disabled children who enter this institution, and others who live with their parents, are considered to be a living reminder of the nuclear tests and their consequences. As the nanny Rakhmat Smagulova explains, the parents of many of these children grew up in the irradiated villages. Some doctors even recommend that such people not have children. But there is little evidence, and the question of whether long-standing radiation causes congenital hereditary pathologies is highly controversial. This topic, like many others in Semey, requires additional research, and it will not be easy to give a definite answer, Muldagaliyev said.
Most local congenital abnormalities are likely to be bypassed. But the consequences could be more insidious, weakening the health of future generations.
The history of the landfill has attracted the attention of scientists and, last but not least, filmmakers for years - and this is a double-edged sword. Yes, public attention is highlighting the plight of radiation victims. But at the same time hangs a shameful label, says Semenova. Many are depressed by negative fame: the city of Semey is mainly known for its sad past, and in fact it is the homeland of outstanding Kazakh poets and artists.
“It's like a stigma on our city,” complains Symbat Abdykarimova, a neurologist from an orphanage. - We live here and we want to be proud of Semey. But journalists come to us from abroad only to talk about the landfill. We don't like it, we want us to have a different glory."
Wudan Yan