What is Rate of Entry?

• A. Acute Exposure
• B. Rate of Entry
• C. Chronic Exposures
• D. Exposure Routes

Answer: (B)

Rate of entry is the speed at which a contaminant enters the body, measured as the amount entering per unit time (for example, mg per hour). This concept matters because the internal dose a person receives depends on how fast the contaminant gets into the body, not just how long someone is exposed or through which route it enters. The rate is influenced by environmental concentration, exposure duration, the pathway of entry (inhalation, ingestion, skin contact), and how readily the substance is absorbed and cleared. This is different from exposure routes, which describe the path the contaminant uses to reach the body, and from exposure duration terms like acute or chronic, which describe how long exposure lasts rather than how quickly entry occurs.