Which statement about lead exposure is true?

Which statement about lead exposure is true?

• A. Most lead is deposited in bone with half-life of about 20 years.
• B. Lead does not accumulate in the body.
• C. Most lead is deposited in bone with half-life of about 10 years.
• D. Lead has a half-life of 100 years in bone.

Answer: (A)

Lead exposure is largely stored in bone, where it acts as a long‑term reservoir. The residence time in bone is on the order of decades, commonly cited as about 20 years. This is why most of the body’s lead ends up in bone and can linger for many years, even after exposure stops. Blood lead levels reflect recent exposure, while the bone stores reflect cumulative burden over time. The statement that most lead is deposited in bone with a half-life of about 20 years best captures this reality. The other ideas aren’t accurate because lead does accumulate in the body and its bone half-life isn’t as short as 10 years nor as long as 100 years in the standard clinical understanding.

Lead exposure is largely stored in bone, where it acts as a long‑term reservoir. The residence time in bone is on the order of decades, commonly cited as about 20 years. This is why most of the body’s lead ends up in bone and can linger for many years, even after exposure stops. Blood lead levels reflect recent exposure, while the bone stores reflect cumulative burden over time. The statement that most lead is deposited in bone with a half-life of about 20 years best captures this reality. The other ideas aren’t accurate because lead does accumulate in the body and its bone half-life isn’t as short as 10 years nor as long as 100 years in the standard clinical understanding.