Distribution of lead in body fluids after ingestion of soft solder

Blood, serum, cerebrospinal fluid, and urine obtained from a patient before and after chelation therapy showed that (1) the ratio of Pb in his cerebrospinal fluid to that in his serum varied from 0.4 to 0.9 and was independent of serum Pb concentration; (2) the fraction of Pb in his serum fell linearly with decreasing blood Pb concentration and changed from 1.6% to 0.33% as his blood Pb concentration changed from 116 micrograms/dl (5.6 mumol/l) to 31 micrograms/dl (1.5 mumol/l); and (3) his renal clearance of Pb from serum varied from 5 ml/min to 36 ml/min. This high value was obtained 11 days after chelation and is attributed to large quantities of Sn in his urine promoting the excretion of Pb. Solder was identified in his stool after discovery of radio-opaque material in his bowel. The Pb isotope ratios of the solder were different from those in his urine when he was first admitted, and showed that he had ingested solder when he had returned home on weekend passes.