Balance between intake and output of lead in normal individuals.

Thompson, J. A. (1970). Brit. J. industr. Med., 27, 189-194. Balance between intake and output of lead in normal individuals. The amount of lead ingested by a group of five 'normal' individuals for a number of consecutive days was determined; during the same period, the amount of lead which was excreted in faeces and urine was also determined and hence, by difference, the amount of lead retained in the body was calculated. The results showed a wide variation from day to day in the lead content of the food, with a range from 70 ,tg to 750 ,g; the average amount was 274 ,ug. The lead ingested was almost totally eliminated in faeces and urine; the amount of lead excreted daily ranged from 140 ,ig to 625 ,ug with an average of 264 ,ug. Only about 10 ,ug on average per day, less than 4% of the average daily intake, was retained. At this rate of retention the lead accumulated would almost wholly account for the 'normal' body burden of lead found by tissue analysis.