We explain what radioactive contamination is, its causes, consequences and examples. Also, how can it be prevented.
What is radioactive contamination?
It is known as radioactive or radioactive contamination to the dispersion in the environment of unstable chemical materials capable of emitting harmful electromagnetic particles, in a physico-chemical phenomenon known as ionizing radiation.
This type of radioactive material can occur in nature under very specific and rare conditions, but They are mostly the result of artificial chemical reactions carried out in human facilities, such as nuclear power plants or laboratories for scientific experimentation.
Radioactive contamination occurs, then, when these radioactive chemical elements are dispersed in the environment, both in the water, the soil or the air itself, and subsequently penetrate the bodies of living beings, transmitting themselves along the chain trophic.
Exposure to radioactivity can cause deep and structural damage to the body, for example altering DNA and causing unpredictable mutations, transmissible to offspring. For this reason, areas contaminated with radioactive material are incompatible with life for a long time, since these chemical elements can be dangerous for centuries.
Some of the most common radioisotopes (dangerous versions) in cases of radioactive contamination are uranium-235 (235U), polonium-210 (210Po), potassium-40 (40K), plutonium-239 (239Pu), curium-244 (244Cm), Americium-241 (241Am) or cobalt-60 (60Co). Depending on the element in question, the levels of danger and duration of contamination may be worse.
Causes of radioactive contamination
Radioactive contamination is rare, as natural levels of exposure to these materials in the atmosphere or soil are so low that their chances of causing large-scale damage are minimal. In fact, pollution is rarely talked about in this sense.
Thus, radioactive contamination events in history have always been the responsibility of the human being, and can be classified into four different categories:
- Contamination by medical waste. Radioactive materials have uses in medicine, as part of radical treatments against certain diseases (such as radiotherapy) or as radical disinfection mechanisms, since when irradiated, the materials are sterilized: not even bacteria can survive certain doses of radioactivity. If these dangerous elements do not have the suitable disposition, they can go to give to the environment and act as polluting elements.
- Pollution for industrial reasons. In this case we are referring mainly to nuclear energy, that is, obtaining electricity through controlled exothermic nuclear reactions. These reactions, at best, cause low environmental impact, but leave long-standing radioactive by-products that require proper storage. Negligence in handling them, or accidents caused by human error or natural catastrophes, can release these elements into the environment.
- Pollution for military reasons. The knowledge of nuclear reactions was put to the test, as history tells it, in terms of achieving a lethal military weapon: the atomic bomb. It is an uncontrolled nuclear chain reaction of immense destructive power that subsequently releases radioactive material at the site of its detonation.
Consequences of radioactive contamination
The consequences of radioactive contamination are extremely serious. Radioactive substances have a damaging effect on all forms of life, and they can also enter their bodies through food or water, and continue to emit harmful particles from within.
By serving as food for other living things, contaminated plants or animals perpetuate contamination, in a destructive chain that can last for the hundreds of years it takes for the radioactive element to stabilize.
For this reason, in areas contaminated in this way all its inhabitants are evacuated, including local fauna, to limit contact with hazardous materials and prevent them from being transported to other environments. Containing contaminated water or dealing with contaminated soil can be even more problematic, but taking the appropriate measures and procedures can limit the damage and even decontaminate the least affected regions.
Examples of radioactive contamination
Some examples of radioactive contamination are:
- The Chernobyl accident. Occurring on April 26, 1986 at the Vladimir Ilyich Lenin nuclear power plant in the city of Pripyat, Ukraine, at that time part of the Soviet Union, is the worst nuclear accident in history. It occurred when the core of reactor 4 of the plant overheated and exploded twice in succession, catching fire in the process, and emitting a cloud of radioactive materials that rose into the atmosphere, full of uranium dioxide, boron carbide, europium oxide, erbium, zirconium and graphite, and it affected around 13 countries in Europe.
- The bombing of Hiroshima and Nagasaki. The event that ended World War II and caused the surrender of Japan was the bombardment of these two cities with atomic bombs on August 6 and 9, 1945. The explosion killed around 105,000 and 120,000 people, 15 to 20 % of which due to radioactive poisoning. These deaths occurred in the days following the bombing, because the region was highly polluted.
- The Fukushima accident I. Occurred on March 11, 2011 in Japan, as a result of an earthquake of magnitude 9 on the seismological scale of magnitude of the moment, and especially the tsunami that it caused next. The Fukushima I power plant was particularly affected by the gigantic 14-meter high wave, which destroyed the auxiliary electricity generators (diesel) that at that time were feeding the coolant pumps of the plant, since the nuclear fission had been off immediately upon sensing the earthquake. When the coolant flow failed, three hydrogen explosions and three nuclear meltdowns occurred, releasing radioactive materials into the environment between March 12 and 15.
How to prevent radioactive contamination?
The prevention of radioactive contamination is complicated, and has to do mainly with proper disposal of hazardous waste, whatever its origin.
The only known material that can act as an insulator for ionizing radiation is lead, so lead is often used to make containers and linings that contain the emission of toxic particles. Unfortunately, this material is not very durable, especially compared to the long periods of activity of radioactive materials.
Another element to take into consideration is the so-called nuclear safety, that is, the set of control, prevention and monitoring measures for industrial activities, medical or whatever type that produces radioactive waste. The tighter the security, the lower the risks of polluting the environment.