Elimination Kinetics of Blood Lead in Workers with Chronic Lead Intoxication

Blood lead elimination half-lives were determined for 65 patients with occupational chronic lead intoxication who were removed from exposure, treated with intravenous EDTA, and followed for periods of up to 2,419 days. The median overall blood lead elimination half-life was 619 days in patients with normal renal function and 1,907 days in patients with renal impairment. Slow-phase elimination half-lives in patients followed for longer than 5 years ranged from 1,658 to 7,189 days. Blood lead concentrations declined during periods of chelation with a mean half-life of 7 days and rebounded to near prechelation concentrations following termination of chelation with a mean doubling time of 27 days. The overall blood lead elimination half-life was positively associated with length of follow-up (p less than 0.001), age (p = 0.04), and duration of exposure (p = 0.02), but was not associated with the initial blood lead concentration following cessation of exposure or the total amount of EDTA received.