Lead Exposure
Exposure to lead and lead chemicals can occur through four routes: ingestion, inhalation, and to a lesser degree, dermal absorption, and endogenous routes.
Entry Routes
- Ingestion: Exposure that most likely results in elevated levels of lead in the blood is through ingestion. The ingestion route includes swallowing contaminated food, water, alcohol, and other foreign bodies containing lead (i.e., jewelry, etc.). Ingestion may also occur when lead is inhaled into the lungs. Mucus may carry the lead out of the lungs to the throat where it can be swallowed and absorbed in the stomach or intestines.
- Inhalation: Inhalation is the second most common pathway of exposure. The amount directly absorbed from the respiratory system into the body depends on particle size, respiratory volume, amount of deposition, and the ability of the lungs to clear and remove inhaled airborne lead (mucociliary clearance).
- Dermal Exposure: Dermal exposure plays a role for exposure to organic lead among workers, but is not considered a significant pathway. Organic lead may be absorbed directly through the skin and is more likely to be absorbed through the skin than inorganic lead.
- Endogenous Exposure: Endogenous exposure to lead may contribute significantly to an individual's current levels of lead in the blood. Once absorbed into the body, lead may be stored for long periods in mineralizing tissue (e.g., teeth and bones) The stored lead may be released again into the bloodstream.
Acute and Chronic Exposure
Acute, short-term overexposure: Lead is a potent, systemic poison that serves no known useful function once absorbed by your body. Taken in unusually large doses, lead can kill you in a matter of days.
Chronic, long-term overexposure: Long-term overexposure can lead to severe damage to your blood-forming, nervous, urinary and reproductive systems.
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1-6. What is the most likely pathway of lead exposure?
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