Conference paper
Biological and clinical effects of continuous exposure to airborne particulate lead
T.B. Griffin
; Institute of Comparative and Human Toxicology, Albany Medical College, Albany, N. Y., USA
F. Coulston
; Institute of Comparative and Human Toxicology, Albany Medical College, Albany, N. Y., USA
H. Wills
; Institute of Comparative and Human Toxicology, Albany Medical College, Albany, N. Y., USA
Abstract
Rats and rhesus monkeys were exposed for 22 hours per day 'lo lead oxide at a concentration of 21.5 µg Pb/cubic meter of air. The year-long exposure elicited a significant increase in the concentration of lead in the blood of both rats and monkeys. The blood-lead levels reached a maximum during the first few months of exposure and did not increase significantly after that time. Elevated concentrations of lead were also detected in lung, liver, kidney and bone of both species. The concentration of lead decreased in the soft tissues of animals removed from the chamber after one year's exposure but remained elevated in bone. The activity of the enzyme δ-aminolevulinic acid dehydrase (ALAD) in circulating erythrocytes was inhibited about 70% in rats exposed to the airborne lead. No reduction of the enzyme activity occurred in brain or liver tissue of either the rats or monkeys. Two experiments were conducted to determine the effects of low level exposure to airborne lead particulates on humans. Male volunteers were exposed 23 hours per clay for about 18 weeks to either 10.9 µg Pb/cubic meter or 3.2 µg Pb/cubic meter of air. In both cases the blood lead levels increased correspondingly and appeared .to plateau after about three months of exposure. Subsequent to that no further increases were observed. About two months after the men left the exposure chamber, their blood leads returned to neat normal levels. There was an increase in urinary lead excretion, but always within the·limits usually considered normal.
Keywords
Hrčak ID:
167410
URI
Publication date:
6.4.1976.
Visits: 919 *