 |
| Module 1: Occupational Hygiene - Section 1: Introduction to Occupational Hygiene |
| OH1.3: Health Effects and Routes of Entry into the Body |
|
| Module 1: Occupational Hygiene - Section 1: Introduction to Occupational Hygiene |
| OH1.3: Health Effects and Routes of Entry into the Body |
 |
 |
 |
 |
 |
Exposure to many of the harmful health hazards may produce either an immediate response (acute health effect) due to intensity of the hazard; or the response may result from exposure over a long period at a relatively lower intensity (chronic health effect).
Acute health effects develop soon after exposure, rapidly reach maximum effect (climax) Acute effects generally develop in response to a high dose or exposure to a high concentration of a substance. The effect may be temporary (skin irritation, nausea or sickness) or it may be permanent (blindness, scars from acid burns, death). If a worker is removed from a source of exposure, acute health effect may be reversible.
Chronic toxic effects develop gradually over a prolonged period of exposure, many years after initial exposure. Once an effect develops it is normally irreversible or recovery tends to be slow when compared to acute effects. Because of the long latency period between exposure and onset of disease, it is often difficult to make a link.
For a chemical to exert its harmful effect, it must first come into contact with or enter the body.
The three main routes of exposure in the workplace are inhalation, absorption, and ingestion.
Inhalation is the most common route of entry of health hazards. Gases and vapours are easily inhaled but inhalation of solid particles depend on their size and shape. The smaller sizes penetrate deeper and have a greater effect. Skin absorption is the second major route of exposure. Those areas of the skin that come into contact with contaminants are the most impacted. The face or hands are the areas of the skin surface that usually come into contact with potentially toxic materials. Dermal absorption may also be enhanced by scratched, roughened, broken or abraded surfaces of the skin. Ingestion is generally not a major route of exposure although there are important exceptions.Workers who mouth breathe or chew gum or tobacco can absorb appreciable amounts of airborne contaminants. If areas used to eat, drink or smoke are contaminated by hazardous substances, or if workers do not wash their hands or remove gloves before eating or smoking, chemicals can enter the body through ingestion.
