Multicompartment kinetic models for lead. II. Linear kinetics and variable absorption in humans without excessive lead exposures.

Multicompartment models with constant fractional transfer rates have been fitted to experimental data on lead metabolism in four subjects studied by M. B. Rabinowitz, G. W. Wetherill, and J. D. Kopple (Science 182, 725-727, 1973; Environ. Health Perspect. 7, 145-153, 1974; Arch. Environ. Health 31, 220-223, 1976; J. Clin. Invest. 58, 260-270, 1976; J. Lab. Clin. Med. 90, 238-248, 1977). Long-term retention is estimated for blood, soft tissue, cortical and trabecular bone pools, and for facial hair. The absorption of lead from diet is shown to change with time, but no evidence was found for other variable or nonlinear kinetic mechanisms of lead metabolism in humans without excessive lead exposure.