In the remote northeastern region of Kazakhstan, not far from the city of Semey, lies Lake Chagan. This expansive body of water, resembling a natural pond, conceals a story both fascinating and haunting.
Lake Chagan, also known as Atom-Kol (translated from Kazakh as the “Atomic” Lake), holds secrets buried deep beneath its placid surface. The lake, with a crater depth of 100 m and a diameter of 400 m, stands as a testament to the unimaginable power unleashed by the nuclear experiment. It is astonishing how something so artificial can appear deceptively natural.
The Chagan test was an unprecedented endeavor. Conducted on January 15, 1965, it was the inaugural experiment in the Soviet Peaceful Nuclear Explosions (PNE) Program. This test had a dual objective: to gather data on the application of nuclear explosives for creating craters and to demonstrate the practical utility of nuclear explosives in the construction of water storage reservoirs. The Soviet intention was to leverage nuclear detonations for a range of industrial objectives, and the Chagan test served as a crucial trial.
Employing a 140 kiloton device strategically placed in a 178-meter deep hole on the dry bed of the Chagan River, Soviet researchers intended to utilize the crater lip as a natural dam during periods of high river flow. Subsequently, a channel was created, enabling the crater to fill up with water and form a reservoir behind it.
During the test, Soviet scientists used a type of nuclear explosive called a low-fission design. It had two parts: a primary fission component and a secondary thermonuclear component. When they set it off, it released energy equivalent to about 5–7 kilotons.1The History of Soviet Nuclear Weapons, Draft Outline VNIIEF/VNIITF, Moscow, 1992.,2USSR Nuclear Weapons Tests and Peaceful Nuclear Explosives, 1949 Through 1990, RFCN-VNIIEF, Sarov, 15RN5-85165-062-1, 1996.
Unfortunately, around 20% of the radioactive materials produced during the explosion escaped into the atmosphere. This led to higher radiation levels on the crater’s edge, reaching 200–300 millisieverts (mSv)/hr (a unit to measure radiation) a few days after the test. For reference, in the United Kingdom, Public Health England has estimated that the average annual radiation exposure for individuals is approximately 2.7 mSv; this exposure primarily results from cosmic irradiation. The main source of this radiation was a substance called Cobalt-60 (60Co) which stays radioactive for about 5.26 years.3Nordyke, M.D. “The Soviet Program for Peaceful Uses of Nuclear Explosions,” July 24, 1996. Link.
In a comprehensive study conducted in 2017, soil activity concentrations of various radionuclides were assessed in the vicinity of the Atomic Lake. The results revealed maximum concentrations of 4000 Bq/kg, 17,000 Bq/kg, 7500 Bq/kg, 22,000 Bq/kg, 10,000 Bq/kg, 16000 Bq/kg, and 6000 Bq/kg, respectively. The primary soil contamination was concentrated in close proximity to the crater of the Atomic Lake, limited to an area within 1–2 km downstream from the crater ridge. The level of contamination is significantly higher than global fallout levels.4Lukashenko, N. N. 2017. “Topical Issues in Radioecology of Kazakhstan. Optimization of Study of the Semipalatinsk Test Site Lands for the Purpose of Their Transfer into Economic Turnover.” Dom Pechati, Issue 5. Kurchatov.
The enduring consequences of the Chagan test are glaringly evident in the radioactive levels present in the lake water that now occupies the crater. The concentrations of radioactive substances in this water, particularly tritium (3H), surpass permissible levels by hundreds of times. The primary human health concern lies in the soil heap zone surrounding Atomic Lake, which extends to a radius of 3–4 kilometers. This zone should be viewed as a significant potential source of secondary environmental contamination, affecting water, vegetation, and air quality.5Nurpeisova, M. B., A. B. Umirbaeva, E. V. Fedorov, and N. A. Miletenko. “Integrated Monitoring-Based Assessment of Deformation and Radiation Situation of Territorial Domains.” Eurasian Mining, no. 1 (2021): 83–87. Link. It is no wonder some locals call it the “dead” lake.6“Atom-Kol. Through the Eyes of an Eyewitness. Nuclear Lakes Nuclear Explosion Chagan.” Accessed July 30, 2023. Link.
Two Soviet newspapers described the test:
В результате было создано прекрасное озеро Чаган с чистой прозрачной водой. Местность преобразилась. На берегу мы находили большие прозрачные кристаллы гипса, которые были вскрыты взрывом.
[As a result, the beautiful lake Chagan was created with clear, transparent water. The terrain has been transformed. On the shore we found large transparent gypsum crystals, which were uncovered by the explosion.]
…Произошло событие, которое так долго ждали. Стояла обычная для этих мест жара. Люди изнывали. Правда, на берегу было чуть прохладнее, но как манила эта безмятежная водная гладь! Поистине, близок локоть, да не укусишь… Пока. Наконец медики дали “добро”, и все обитатели поселка побежали на пляж. Купались долго, от души…7Atomic Lake. 2011. “Two Patrons.” Accessed from Link.
[…The long-awaited event has happened. The heat was just as it usually is for these places. The people were weary (note: likely from the heat). True, it was a little cooler on the shore, but oh how this serene water surface beckoned! Indeed, the elbow is close, but you couldn’t bite it… at least not yet (an expression: the water may seem so close, but you couldn’t reach it/interact with it quite yet). Finally, the doctors gave the go-ahead, and all the inhabitants of the village ran to the beach. They bathed for a long time, from the soul (with great enthusiasm)…”
Efim Pavlovich Slavsky, First Deputy Minister of Medium Machine Building8The government ministry of the Soviet Union that supervised the Soviet nuclear industry, including production of nuclear warheads., was proud of this creation, commissioning a color film to be made for wide screening.9Atomic Lake. 2011. “Two Patrons.” Accessed from Link.
Local Interactions with Lake
The Chagan River’s water is not commonly used for drinking by the local population, but it serves as a vital source of livestock feed water throughout the region. The seemingly harmless practice of using Chagan River water for livestock feed can have alarming consequences, as it sets off a chain reaction that culminates in the accumulation of heavy metals in the human body. This chain begins with water contamination, which is then passed on to animals that consume the tainted water. Finally, when humans consume these animals, they inadvertently absorb the accumulated heavy metals.10Gorlachev, I., P. Kharkin, M. Dyussembayeva, S. Lukashenko, G. Gluchshenko, L. Matiyenko, D. Zheltov, A. Kitamura, and N. Khlebnikov. “Comparative Analysis of Water Contamination of the Shagan River at the Semipalatinsk Test Site with Heavy Metals and Artificial Radionuclides.” Journal of Environmental Radioactivity 213 (March 1, 2020): 106110. Link.
In the 1940s, carp were introduced into a watershed in Kazakhstan, and since then, they have thrived and now populate the Atomic Lake. Despite being more radioactive than the water itself, locals continue to fish for these carp—some of who grow to be larger than 1 meter long—and consume them.11“Investigation on Carp (Cyprinus Carpio L.) Population from Baikel Nuclear Testing Crater Water.” Tethys Aqua Zoological Research 1 (January 1, 2002): 97–107.
Carp, being opportunistic feeders, consume insects and grasses around the lake, inadvertently concentrating the contaminants in their flesh.12Ibid. While grass does manage to grow around the lake, there is an apparent absence of birds or terrestrial animals in the vicinity. Although it is not recommended to eat the few fish that can survive the radioactive waters, some locals still choose or have no choice but to do so, putting their health at risk. Having been told of its safety, it isn’t hard to see why this may be the case. Clever businessmen, too, offer giant carp in the markets of Semipalatinsk to buyers who are passing through and do not yet know the dangers of the lake.13“Atomic Lake Chagan, Kazakhstan: Description, History and Interesting Facts.” Accessed July 30, 2023. Link.
Lake Chagan, with its haunting beauty, serves as a poignant symbol of the profound impact of nuclear testing on the Kazakh Steppe.
For an English transcript, click here. Note the example of local fishing beginning at 1:35.
