Lead levels in ancient and contemporary Japanese bones.

During the past few centuries, lead production, consumption and emissions, to our total environment have increased remarkably. We have determined the concentrations of lead in 41 well-preserved ancient and 11 contemporary rib bones of a mature age (40-60 y), with a view of historically evaluating lead exposure in humans. The oldest Japanese bones (1000-300 B.C.) were found to contain a mean of 0.58 microgram Pb/g dry wt and a mean molar ratio of lead to calcium of 0.6 x 10(-6), compared with 4.7-5.2 x 10(-6) in the bones of the Edo era (1600-1867 A.D.) and contemporary residents in Japan. The mean molar ratios of female bones were always higher than those of male bones for each era. From this fact we may assume that facial cosmetics were one of the main routes of lead exposure among the ancient Japanese, especially those who lived during the Edo era.