Diurnal Variation of Urinary Lead Excretion

Abstract

Laboratory studies of 6 persons. 3 with no known exposure to Pb compounds and the rest with some exposure to Pb arsenate, demonstrated diurnal variation in urinary Pb excretion which occurred independently of previous exposure of the individual or time of yr. Diurnal variation of P and As was found. Wide daily variations were found for measurements of urinary Pb conc., rate of excretion and total urine vol. The total daily urinary Pb outputs were very constant for given individuals during 3 or 4 day periods. Marked diuresis did not markedly increase the rate nor the total quantity of Pb excreted in the urine. Blood Pb values on morning specimens were higher than the corresponding afternoon quantities. First morning specimens were representative samples of the corresponding 24-hr. specimens. The measurement of 24-hr. outputs was advocated.