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Published September 1991 | public
Journal Article

Natural skeletal levels of lead in Homo sapiens sapiens uncontaminated by technological lead

Abstract

Lead, Ba and Ca concentrations were determined in tooth enamel, femur and rib from buried skeletons of PreColumbian Southwest American Indians, 10 subjects who lived 1000 years ago on the Pacific coast at 34°N, and 13 subjects who lived 700 years ago in a desert valley tributary of the Colorado River at 37°N 111°W, both groups living in environments uncontaminated by technological Pb. For the coastal tribe, average Pb/Ca ratios were 1.1 × 10^(−7) in enamel, 2.3 × 10^(−7) in femur and 4.7 × 10^(−7) in rib, while Ba/Ca ratios were 1.2 × 10^(−5) in enamel, 32 × 10^(−5) in femur and 38 × 10^(−5) in rib (wt ratios). For the desert tribe, average Pb/Ca ratios were 4 × 10^(−7) in enamel, 11 × 10^(−7) in femur and 37 × 10^(−7) in rib, while Ba/Ca ratios were 1.1 × 10^(−5) in enamel, 7.5 × 10^(−5) in femur and 6.2 × 10^(−5) in rib. It is shown that biologic levels of Pb and Ba in buried femur and rib at both burial sites and in buried enamel at the Arizona site are obscured by excessive diagenetic additions of Pb and Ba from soil moisture. It is shown that one-third of the Pb in enamel at the Malibu site is biologic, yielding a skeletal Pb/Ca (wt) ratio of 4 × 10^(−8). This is equivalent to a mean skeletal concentration of 13 ng Pb g^(−1) bone ash, and a mean natural body burden of 40 μg Pb/70 kg adult Homo sapiens sapiens, uncontaminated by technological Pb. This value is about one-thousandth of the mean body burden of 40 mg industrial Pb/70 kg adult American today, which indicates the probable existence within most Americans of dysfunctions caused by poisoning from chronic, excessive overexposures to industrial Pb.

Additional Information

© 1991 Published by Elsevier B.V., Amsterdam. Received October 15, 1990; accepted November 1, 1990. We gratefully acknowldege the help of Prof. Gail Kennedy, UCLA Department of Anthropology, who provided access to the skeletal collections from which the bone samples used in this study were taken, and her research notes on gender and age of the Malibu individuals. We are grateful to Dr S.I. Mishra (M.D.), graduate student in the Department of Social Ecology at UCI, for assisting in the isolation of some bone and enamel segments from samples. We honor the Canalino-Chumash and Kayenta-Anasazi People who, through their contributions, made possible this study of the development of scientific knowledge concerning a major social dysfunction arising from the technological evolution of human cultures. These People continue to live through their participation in this study as respected kin within the community of humankind. A major portion of this study was funded by US National Institute of Environmental Health Sciences Grant PHS4 ES04 291 A-01. A major portion of the study was funded by The California Institute of Technology. The National Government of Japan and The Muroran Institute of Technology in Muroran, Hokkaido, Japan, financed Prof. Shirahata's Visiting Research Associate appointment at The California Institute of Technology. Additional funds were provided to the study from Start-up funds in the Program of Social Ecology, University of California, Irvine.

Additional details

Created:
August 20, 2023
Modified:
October 26, 2023