How Nuclear Radiation Causes Cancer?
Mankind has been exploring different avenues of energy from time immemorial. But, it was only around the 1930s that scientists discovered nuclear energy. By 1960, developed nations were adept at trapping this very powerful energy source for utilizing it in useful purposes.
But, this energy has its other side as well. If it is not checked, the existence of the entire life on earth can be at peril. This article tries to understand why and how such a scenario can emerge.
What is Nuclear Radiation?
Matter is made of atoms and molecules. An atom has three fundamental particles known as electrons, protons and the neutrons. Its central entity is the nucleus. The electrons revolve around the nucleus like the planets around the sun. The protons and the neutrons exist inside the nucleus.
An important and fundamental property of these particles is charge. While electrons are negatively charged, protons have positive charge. Neutrons are charge-less or neutral. According to a basic law of nature, like charges repel each other and unlike charges attract.
Owing to this principle, the protons repel each other and can tear the nucleus apart. If the nucleus is well in place, it is because, it spends certain amount of energy known as binding energy to keep the repelling protons well inside the volume of the nucleus.
The presence of charge-less neutrons which co-exist with the protons also helps in reducing the repulsive force between the latter particles, thus keeping the nucleus stable.
But, there are certain unstable atoms which have very less binding energy. As a consequence of this, the components of the nucleus are left to escape from such atoms. These particles emerge from the nucleus as nuclear radiation. This event is called radioactivity. The nuclear radiation is in the form of three types. They are alpha particles, beta particles and gamma rays.
What is Cancer?
Human body is made up of cells. They are in fact the basic building blocks of life. These cells also contain a central structure known as the nucleus. Inside the nucleus of a cell, there are genetic materials called the DNA and RNA molecules. These substances come together to form genetic instructions called chromosomes. A chunk of these instructions form genes.
Cells follow genes in order to know their functioning. The functions are carried out by naturally produced chemical substances in the body called proteins. The RNA molecules read the instructions of the cells made up of DNA molecules and produce these proteins.
Certain environmental factors can change the chemical structure of the genes. They can either knock out a DNA molecule from its specific site in a chromosome or replace it by another molecule. This event is called mutation. In such a scenario, the genetic instructions get corrupted. Nuclear radiation is one such environmental factor.
The consequence is that healthy cells start behaving like rogue cells. They divide at an uncontrollable pace in contrast to a regulated division of healthy cells. They interfere with the functioning of nearby healthy cells. They do not undergo natural death as programmed for healthy cells. All these features are characteristics of the dreadful ailment called cancer.
Thus, cancer is a dangerous state of the body where its building blocks turn malignant and pose threat to the very existence of the being.
How Nuclear Radiation Causes Cancer?
The radiation emitted by the nucleus of an unstable atomic substance can either be an alpha particle, beta particle or a gamma ray. Alpha particle is relatively massive and cannot penetrate deep into the body directly. It has to be inhaled for causing destruction inside the body.
Beta particles are lighter particles and more energetic than the former. In spite of this nature, even these particles should be inhaled in order to cause physical destruction in humans.
Gamma rays are not particles. They are packets of pure energy. In this way, they have very high penetrating ability inside the body. They can cause destruction in two ways, namely, directly and indirectly.
Directly, gamma rays can transfer their total energy to the DNA molecules of the chromosomes inside a cell’s nucleus. This can lead to change in the genes of the cells making them malignant.
Otherwise, the energy of the gamma rays can knock out the electrons from the hydrogen and oxygen atoms of the water molecules. 80 percent of human body is made up of water. There is no drought of these molecules inside humans.
The number of electrons outside the nucleus is exactly same as the number of protons inside it. In this way, there is a balance of positive and negative charges in an atom. When nuclear radiation uses its energy to knock out electrons from atoms, there is instability in the distribution of total charge. The event is called ionization.
The knocked out electron has its own independent existence with its negative charge, while the earlier atom now turns into a positively charged ion. Presence of these charged entities inside the body is destructive for the cells.
Though alpha and beta particles have less penetrative abilities, they retain their energy of destruction when inhaled directly into the body. Whenever a nuclear blast takes place, inhalation of these particles by the humans in the surrounding areas is a foregone conclusion. Only the extent of inhalation varies from one region to another.
Direct interaction of the nuclear radiations can cause cancer owing to the damage of genes. Indirect interaction causes ionization which can also lead to cell death or its damage. Though there is an inherent repair mechanism inside the body to address damaged cells, the process can turn out be fatal or partially effective.
While the former possibility of cell repair means its death, the latter eventuality implies that the cells can turn cancerous.
The above mentioned mechanisms of the effects of nuclear radiations on the cells happen over a period of time. The state of cancer is diagnosed after years of being exposed to these harmful rays. The severity of the effects depends on the area of the body exposed and the amount of nuclear radiation absorbed by it.