Kinetics of lead following intravenous administration in man

Whole body retention of lead (Pb) and lead kinetics in blood, urine and faeces were determined over 2 weeks following i.v. administration of 203Pb-labelled chloride to 2 subjects. Pb was retained with a biological half-life of 73 days (mean). After day 1 Pb excreted in urine and faeces remained fairly constant at 1% and 0.3% of administered dose, respectively. There was a daily loss of 0.5% by other routes. There was a rapid clearance of isotope from plasma with a half-life of 1 min (mean). At 60 min 45% of the administered dose was in erythrocytes; this changed little over the 2 weeks.