Radioactivity is the property of some substances to emit ionizing radiation. Ionizing radiation is particles with great energy that are capable of altering and damaging molecules in their path as they pass through matter.
Radioactive contamination and exposure to radioactivity occur when there is a release of radioactive material into the atmosphere from sources such as a nuclear power plant or an atomic bomb explosion. There are also natural sources of radiation in land, water, and air.
What radiation do we normally receive?
We are routinely exposed to natural radiation that exists from space and from radioactive material in soil, water, and air. Likewise, there are artificial sources of radiation, such as X-ray machines.
According to data provided by the World Health Organization (WHO), a person receives about 3 millisieverts (mSv), the measure of radiation levels, throughout the year, which is considered a harmless and tolerable amount. Exposure below 100 mSv per year generally does not pose any health risk or cause symptoms.
How does the body absorb them?
There are two ways, internal contamination and external irradiation. Internal contamination involves the entry of radioactive material through the digestive tract (contaminated food or water) or through the respiratory tract, while external irradiation is caused by exposure to external sources or by adhesion of radioactive material to the skin or clothing, which can be removed by washing the body.
What kind of effects does radiation have on the body?
Ionizing radiation has great penetrating power so it can reach the most vulnerable part of a cell, the chromosomes in the cell nucleus. All ionizing radiation can produce biological changes in the molecules of organisms, either directly through different mechanisms, or indirectly through the formation of free radicals or agents that are harmful to health. Thus, ionizing radiation can cause damage both by interacting with organs and tissues, and by affecting the genetic material of cells.
The effects that exposure to radiation has on the human body are diverse. The repercussions depend on the distance each person is from the source of radiation emission, its sensitivity, the radiation dose received and the radioactive materials emitted.
What risks do they pose for health?
At higher doses of radiation, greater repercussions on health, as they can have consequences on the central nervous system, blood cells and the immune system.
In general terms, the health effects of radiation are divided into acute and chronic.
Acute effects occur immediately and are burns, hair loss and a series of symptoms (acute radiation syndrome) caused by a high radiation dose (> like 1000 mSv). Irradiation syndrome occurs after irradiation emitted by an external source that reaches the entire body acutely and in a short space of time. It gives rise to alterations in the bone marrow (in the production of blood cells), symptoms at the level of the gastrointestinal system and the central nervous system.
In contrast, chronic or long-term effects are seen over months or years and can persist for a long time. It mainly increases the risk of suffering from cancers (such as leukemia or thyroid cancer) and of suffering from congenital malformations. This is due to the fact that ionizing radiation causes changes in the DNA, which contains the genetic information of the organism, which causes mutations in said information, mutations that can have effects on subsequent generations.
