Effects of the Chernobyl Disaster
On April 26th, 1986 the Chernobyl Nuclear Power plant in Soviet Ukraine experienced an unexpected power surge during a routine systems test. A series of steam explosions exposed part of the reactor to open air, causing it to ignite, sending an enormous plume of radioactive fallout into the atmosphere. 31 plant workers and firefighters were killed as a direct result of the accident, but the effects of the disaster were far-reaching. To date, it is the largest power plant disaster in history and was the only disaster classified as a level 7 on the International Nuclear Event Scale until the Fukushima Daiichi nuclear disaster in 2011.
In the days following the incident, Russian authorities did not share that the incident had occurred. It wasn’t until April 28th when plant workers at a nuclear facility in Sweden noticed high levels of radiation coming into the plant from the outside that the Western world found out about Chernobyl. In addition to this, Soviet authorities did not start evacuating the city until over 24 hours had passed and when they had announced the evacuation, they noted it would be temporary. The speed and honesty by which the Soviet authorities operated hindered evacuation which risked the lives of the 49,000 residents of Pripyat.
Following the Chernobyl disaster, much of Europe experienced large amounts of fallout, particularly from three radioactive isotopes: cesium-137, strontium-90, and iodine-131. While strontium-90 and cesium-137 are the two largest causative factors in keeping the area surrounding Pripyat, Ukraine (the Chernobyl exclusion zone) closed.
Radioisotopes Released & Their Half-Lives
The Red Forest & Wildlife in the Exclusion Zone
The Red Forest, located just outside Pripyat, is considered to be one of the most contaminated places in the world. It is thus named because of the red color of the dead trees after the disaster. Because the Red Forest was downwind from the Chernobyl Plant when the plume was released, it received the largest dose of radiation.
Unfortunately, the presence of radioactive material in the forest has hindered organic decomposers such as bacteria and fungi. Because of this, dead plant material in the Red Forest is building up, posing a threat for forest fires that could further spread radioactive material.
Despite the initial effect radiation had in the Red Forest, the forest has thrived in the past 30 years without the presence of humans. Trees have slowly encroached into the city, eventually covering the city and wildlife has begun to flourish. The radiation keeping humans away has caused Pripyat to become, arguably, the most protected animal sanctuary in the world. However, this comes at a price to both flora and fauna. An increase in genetic mutations in wildlife in the Exclusion Zone has been noted.
Birds have been particularly affected, with an overall lower reproductive and survival rates and an increased incidence of albinism in barn swallows.
Flora has also been affected by the incident. For example, studies have shown that a disproportionate number of young trees in the area are growing in odd, twisted shapes. This is due to problems with hormone signals which tell trees “which way is up.”
The Effects on the Liquidators
Following the events of the Chernobyl disaster, thousands of people were coerced by the Soviet Union by means of direct order and the withholding of information of the nature of the disaster to clean up and seal off the area. Altogether, upwards of 530,000 people (known as ‘liquidators’) have been involved in the cleanup since the disaster.
Liquidators were both exposed to radiation and the poisonous materials used to seal off and contain the area. They were responsible for activities such as the removal of hazardous waste both inside and outside of the plant, the evacuation of the 49,000 residents of the city, extermination of domestic animals left in homes, and building a protective foundation to protect the surrounding aquifer.
Studies on the effects of radiation on the Liquidators has proved difficult. Liquidators received varying doses of radiation based on the job they were given and the length of their term. In addition to this, the fall of the Soviet Union allowed people involved in the cleanup greater freedom to disperse throughout the former Soviet Union and the world.
Despite the difficulties in studying how the cleanup affected the Liquidators, many studies have been carried out, with controversial results. Some studies show higher cancer risk throughout the population of liquidators and some show no increased incidence. In most studies, however, among the liquidators who were later diagnosed with cancer, a higher percentage of them had thyroid cancer than the general population. Another study showed there was also an increase in the incidence of brain cancer. However, the authors of this paper asserted this could be because of better and more frequent cancer screening received by liquidators in comparison to the general population of the Soviet Union. A paper released by the UN did, however, cite a dramatic increase in thyroid cancer, particularly in children and adolescents, conveying a higher incidence in the population at large.
The Effects on Groundwater, the Pripyat River, and Kiev’s Water Supply
Despite the high solubility of cesium-containing salts, it has been argued that the groundwater surrounding the site was initially not directly affected by the disaster. Since the isotope of iodine had long decayed and the isotopes of strontium and cesium mostly settled and adsorbed to soil surfaces, the groundwater was largely protected. However, remediation efforts such as the burial of trees killed off by the initial blast of radiation brought the radiation in direct contact with the water table which may be a large factor in water contamination.
When the accident occurred at the nuclear power plant, the nearby Pripyat River was flooded (as it was the wet season.) Since the Pripyat River feeds into one of Europe’s largest rivers, the Dnieper River, this quickly became a problem in the days following the accident. Kiev, the capital and largest city of the Ukraine, located just over 60 miles from Pripyat, drew water from the Dnieper reservoir.
Much of the Ukraine experienced high levels of cesium-137 and strontium-90 in drinking water. Official remarks from governing officials, however, assured residents that the fallout was insoluble and had settled to the bottom of the river. Despite this, the safety guidelines for the amount of radioactive iodine allowed in drinking water were temporarily raised so that the water from the reservoir would pass as “safe.”
Within two months, Kiev’s halted its use of the Dnieper reservoir, moving operations to the Desna reservoir instead. It should also be noted that the Dnieper reservoir also carries radioactive waste from the Prydniprovsky Chemical Plant radioactive dumps. There are nine leaking open-air radioactive waste dumps located throughout the Ukrainian city of Dniprodzerzhynsk (a port on the Dnieper River.)
As a part of the clean-up process, as previously mentioned, coal miners were employed to build a foundation to prevent contamination from the power plant from reaching the watershed. While this has largely protected the aquifer from radiation in the days since its construction, it only protects the river from radiation inside what remains of the Chernobyl plant and does not protect against rainwater runoff from the contaminated areas surrounding the plant.
Did you know?
Despite the accident in 1986, Chernobyl's last reactor wasn't shut down until 2000.
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The Effects of the Chernobyl Disaster on Europe
While Belarus received the short-end of the stick in terms of contamination and the Ukraine was ground-zero for the incident, much of Europe was affected by the Chernobyl nuclear plant disaster.
Despite the efforts to protect the water supply, bioaccumulation of radiocesium in fish quickly became an issue, even in closed lakes (no tributaries) from fallout carried outside of the Ukraine. This effect was seen not only in the Ukraine and Belarus, but in parts of Russia, Germany, Great Britain, Sweden, Finland, and Norway.
Because fungi readily take up cesium-137, livestock feed was easily contaminated thus causing cesium-137 to bioaccumulate in livestock. This was (and still is) a problem throughout Europe.
As recent as 2010, over one thousand wild boars hunted in Germany were found to be contaminated with radiation above Germany’s allowable limit. In 2009, around 18,000 livestock in Norway were tested and declared unsafe for consumption until they had been fed food free of contaminants until declared safe for slaughter. The number of contaminated livestock decreased to 1,900 in 2012. However, this could be due to moving livestock to different feeding grounds.
Immediately after the Chernobyl disaster, the movement more than 4.2 million sheep throughout the United Kingdom was restricted to prevent contamination. Slowly, the restrictions were lifted with all restrictions being removed from Northern Ireland in 2000, restrictions in Scotland were removed in 2010, and by 2012, all restrictions on sheep movement had been lifted throughout the United Kingdom, a good 30 years after the disaster.
© 2015 Melanie