The body can be exposed to xenobiotics by three routes:
- Inhalation (breathing)
- Ingestion (food and drink)
- Skin contact or injection (through the skin)
These routes can be specific for each xenobiotic.
Inhalation is the main route of exposure to xenobiotics and accounts for about 80% of the amount of material absorbed by the body.
Xenobiotics can rapidly enter the bloodstream through the mucous membranes in the ENT system (mouth, nose, throat) and through the lungs.
Volatile organic compounds (VOCs) pass the lung barrier very easily.
Exposure through ingestion
Ingestion of food and water is one of the main routes of exposure of the body to xenobiotics and accounts for about 20% of the material absorbed. It can also be from medicines or food supplements taken orally (liquid, powder, tablet, capsule).
Once in the mouth, xenobiotics can enter the bloodstream through the mucous membranes in the ENT system (mouth, nose, throat).
During digestion, depending on the chemical nature of the xenobiotic (solubility in water), a greater or lesser proportion of the xenobiotic enters the bloodstream through the gastric (stomach) and intestinal mucosa.
Xenobiotics that do not pass into the body during digestion are eliminated in the faeces (excrement).
This route of exposure is minimal compared to inhalation and ingestion, the substance passes through the skin. This is mainly through spraying with liquids and application of creams or cosmetics.
The skin is irrigated by blood vessels and the substances in contact with the skin can migrate into the cells of the epidermis and then into the blood that irrigates the skin.
In the case of an injection, the substances are introduced directly into the muscles or the blood.