Clair Cameron Patterson
Encyclopedia
Clair Cameron Patterson (June 2, 1922 – December 5, 1995) was a geochemist born in Mitchellville, Iowa
, United States
. He graduated from Grinnell College
in Grinnell, Iowa, received his Ph.D. from the University of Chicago
, and spent his entire professional career at the California Institute of Technology
.
Patterson developed the uranium-lead dating
method into lead-lead dating
, and by using lead
isotopic
data from the Canyon Diablo meteorite, he calculated an age for the Earth
of 4.55 billion years; a figure far more accurate than those that existed at the time and one that has remained unchanged for over 50 years.
Patterson had first encountered lead contamination in the late 1940s as a graduate student at the University of Chicago
. His work on this led to a total re-evaluation of the growth in lead concentrations in the atmosphere and the human body from industrial causes and his subsequent campaigning was seminal in the banning of lead additives to gasoline and lead solder in food cans.
and graduated from Grinnell College
in chemistry where he met his wife, Lorna (Laurie) McCleary. They both moved to the University of Iowa
for graduate work where he did an M.A. in molecular spectroscopy
. Both were then sent to work on the Manhattan Project
, first at the University of Chicago and then at Oak Ridge, Tennessee
where he encountered mass spectrometry
.
After the war they returned to Chicago where Laurie took a research job as an infrared spectroscopist to support Pat whilst he did a Ph.D. at the University of Chicago under Harrison Brown. After a postdoctoral year at Chicago, Patterson moved with Brown to the Division of Geology (later the Division of Geological and Planetary Sciences) at the California Institute of Technology
(Caltech) in 1952 as founding members of its geochemistry
program. Pat remained at Caltech for the rest of his life. He and Laurie had four children.
of the Solar System
, and thus by measuring the age of one of these rocks the age of the Earth would be revealed. Gathering the materials required time, and in 1953, Clair Cameron Patterson had his final specimens from the Canyon Diablo meteorite
. He took them to the Argonne National Laboratory
, where he was granted time on a late model mass spectrometer.
In a meeting in Wisconsin soon afterward, Patterson revealed the results of his study. The definitive age of the Earth
is 4.550 billion years (give or take 70 million years). This number still stands although the margin of error is now down to about 20 million years.
The limitations of the analytic procedures led to him using other approaches. He found that deep ocean water contained 3-10 times less lead than surface water, in contrast to similar metals such as barium. This led him to doubt the commonly held view that lead concentrations had only grown by a factor of two over naturally occurring levels.
Patterson returned to the problem of his initial experiment and the contamination he had found in the blanks used for sampling. He determined through ice-core samples from Greenland that atmospheric lead levels had begun to increase steadily and dangerously soon after tetra-ethyl lead
began to see widespread use in fuel, when it was discovered to reduce engine "knock" in internal combustion engines. Patterson subsequently identified this, along with the various other uses of lead in manufacturing, as the cause of the contamination of his samples, and because of the significant public-health implications of his findings, he devoted the rest of his life to removing as much introduced lead from the environment as possible.
In his effort to ensure that lead was removed from gasoline (petroleum), Patterson fought against the lobbying power of the Ethyl Corporation
(which employed Kehoe), against the legacy of Thomas Midgley
— which included tetra-ethyl lead and chlorofluorocarbon
s) — and against the lead additive industry as a whole. In A Short History of Nearly Everything
, author Bill Bryson
notes that following his criticism of the lead industry he was refused contracts with many research organizations, including the supposedly neutral United States Public Health Service. In 1971 he was excluded from a National Research Council
panel on atmospheric lead contamination, which was odd considering he was the foremost expert on the subject at that time.
Patterson's efforts ultimately led to the Environmental Protection Agency
announcing in 1973 a reduction of 60-65% in phased steps, and ultimately the removal of lead from all standard, consumer, automotive gasoline in the United States by 1986. Lead levels within the blood of Americans are reported to have dropped by up to 80% by the late 1990s.
He then turned his attention to lead in food where similar experimental deficiencies had masked the increase. In one study he showed an increase in lead levels from 0.3 to 1400 nanograms per gram in certain canned fish compared with fresh, whilst the official laboratory had reported an increase of 400 to 700. He compared the lead, barium and calcium levels in 1600 year-old Peruvian skeletons and showed a 700 to 1200 fold increase in lead levels in modern human bones with no comparable changes in the others.
In 1978 he was appointed to an NRC panel which accepted many of the increases and the need for reductions but argued the need for more research. His opinions were expressed in a 78-page minority report which argued that control measures should start immediately, including gasoline, food containers, paint, glazes and water distribution systems. Thirty years later, most of these have been accepted and implemented in the United States and many other parts of the world.
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. He graduated from Grinnell College
Grinnell College
Grinnell College is a private liberal arts college in Grinnell, Iowa, U.S. known for its strong tradition of social activism. It was founded in 1846, when a group of pioneer New England Congregationalists established the Trustees of Iowa College....
in Grinnell, Iowa, received his Ph.D. from the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
, and spent his entire professional career at the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
.
Patterson developed the uranium-lead dating
Uranium-lead dating
Uranium-lead is one of the oldest and most refined of the radiometric dating schemes, with a routine age range of about 1 million years to over 4.5 billion years, and with routine precisions in the 0.1-1 percent range...
method into lead-lead dating
Lead-lead dating
Lead-lead dating is a method for dating geological samples, normally based on 'whole-rock' samples of material such as granite. For most dating requirements it has been superseded by uranium-lead dating , but in certain specialized situations it is more important than U-Pb dating.-Decay equations...
, and by using lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
isotopic
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
data from the Canyon Diablo meteorite, he calculated an age for the Earth
Age of the Earth
The age of the Earth is 4.54 billion years This age is based on evidence from radiometric age dating of meteorite material and is consistent with the ages of the oldest-known terrestrial and lunar samples...
of 4.55 billion years; a figure far more accurate than those that existed at the time and one that has remained unchanged for over 50 years.
Patterson had first encountered lead contamination in the late 1940s as a graduate student at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
. His work on this led to a total re-evaluation of the growth in lead concentrations in the atmosphere and the human body from industrial causes and his subsequent campaigning was seminal in the banning of lead additives to gasoline and lead solder in food cans.
Early life
Clair (Pat) Patterson was born in Mitchellville, IowaMitchellville, Iowa
Mitchellville is a city in Polk and Jasper counties in the U.S. state of Iowa. The population was 1,715 at the 2000 census.The Polk County portion of Mitchellville is part of the Des Moines–West Des Moines Metropolitan Statistical Area, while the Jasper County portion is part of the Newton...
and graduated from Grinnell College
Grinnell College
Grinnell College is a private liberal arts college in Grinnell, Iowa, U.S. known for its strong tradition of social activism. It was founded in 1846, when a group of pioneer New England Congregationalists established the Trustees of Iowa College....
in chemistry where he met his wife, Lorna (Laurie) McCleary. They both moved to the University of Iowa
University of Iowa
The University of Iowa is a public state-supported research university located in Iowa City, Iowa, United States. It is the oldest public university in the state. The university is organized into eleven colleges granting undergraduate, graduate, and professional degrees...
for graduate work where he did an M.A. in molecular spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
. Both were then sent to work on the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...
, first at the University of Chicago and then at Oak Ridge, Tennessee
Oak Ridge, Tennessee
Oak Ridge is a city in Anderson and Roane counties in the eastern part of the U.S. state of Tennessee, about west of Knoxville. Oak Ridge's population was 27,387 at the 2000 census...
where he encountered mass spectrometry
Mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
.
After the war they returned to Chicago where Laurie took a research job as an infrared spectroscopist to support Pat whilst he did a Ph.D. at the University of Chicago under Harrison Brown. After a postdoctoral year at Chicago, Patterson moved with Brown to the Division of Geology (later the Division of Geological and Planetary Sciences) at the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
(Caltech) in 1952 as founding members of its geochemistry
Geochemistry
The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks, water, and soils, and the cycles of matter and energy that transport the Earth's chemical components in time and space, and...
program. Pat remained at Caltech for the rest of his life. He and Laurie had four children.
Estimate of the Earth's age
Harrison Brown of the University of Chicago developed a new method for counting lead isotopes in igneous rocks, and assigned it to Clair Cameron Patterson as a dissertation project in 1948. During this period he operated under the assumption that meteorites are left-over materials from the creationCosmogony
Cosmogony, or cosmogeny, is any scientific theory concerning the coming into existence or origin of the universe, or about how reality came to be. The word comes from the Greek κοσμογονία , from κόσμος "cosmos, the world", and the root of γίνομαι / γέγονα "to be born, come about"...
of the Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
, and thus by measuring the age of one of these rocks the age of the Earth would be revealed. Gathering the materials required time, and in 1953, Clair Cameron Patterson had his final specimens from the Canyon Diablo meteorite
Canyon Diablo meteorite
The Canyon Diablo meteorite comprises many fragments of the asteroid that impacted at Barringer Crater , Arizona, USA. Meteorites have been found around the crater rim, and are named for nearby Canyon Diablo, which lies about three to four miles west of the crater.-History:The asteroid fell about...
. He took them to the Argonne National Laboratory
Argonne National Laboratory
Argonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
, where he was granted time on a late model mass spectrometer.
In a meeting in Wisconsin soon afterward, Patterson revealed the results of his study. The definitive age of the Earth
Age of the Earth
The age of the Earth is 4.54 billion years This age is based on evidence from radiometric age dating of meteorite material and is consistent with the ages of the oldest-known terrestrial and lunar samples...
is 4.550 billion years (give or take 70 million years). This number still stands although the margin of error is now down to about 20 million years.
Tracing the geochemical evolution of the Earth
His ability to isolate microgram quantities of lead from ordinary rocks and determine their isotope composition led him to examining the lead in ocean sediment samples from the Atlantic and Pacific. Deriving from the different ages at which the landmasses had drained into the ocean, he was able to show that the amount of anthropogenic lead presently dispersed into the environment was about eighty times the amount being deposited in the ocean sediments: the geochemical cycle for lead appeared to be badly out of balance.The limitations of the analytic procedures led to him using other approaches. He found that deep ocean water contained 3-10 times less lead than surface water, in contrast to similar metals such as barium. This led him to doubt the commonly held view that lead concentrations had only grown by a factor of two over naturally occurring levels.
Patterson returned to the problem of his initial experiment and the contamination he had found in the blanks used for sampling. He determined through ice-core samples from Greenland that atmospheric lead levels had begun to increase steadily and dangerously soon after tetra-ethyl lead
Tetra-ethyl lead
Tetraethyllead , abbreviated TEL, is an organolead compound with the formula 4Pb. An inexpensive additive, its addition to gasoline from the 1920's allowed octane ratings and thus engine compression to be boosted significantly, increasing power and fuel economy...
began to see widespread use in fuel, when it was discovered to reduce engine "knock" in internal combustion engines. Patterson subsequently identified this, along with the various other uses of lead in manufacturing, as the cause of the contamination of his samples, and because of the significant public-health implications of his findings, he devoted the rest of his life to removing as much introduced lead from the environment as possible.
Campaign against lead poisoning
Beginning in 1965, with the publication of Contaminated and Natural Lead Environments of Man, Patterson tried to draw public attention to the problem of increased lead levels in the environment and the food chain due to lead from industrial sources. Perhaps partly because he was criticizing the experimental methods of other scientists, he encountered strong opposition from recognized experts such as Robert A. Kehoe.In his effort to ensure that lead was removed from gasoline (petroleum), Patterson fought against the lobbying power of the Ethyl Corporation
Ethyl Corporation
Ethyl Corporation is a fuel additive company headquartered in Richmond, Virginia. The company is a manufacturer, blender and distributor of fuel additives...
(which employed Kehoe), against the legacy of Thomas Midgley
Thomas Midgley, Jr.
Thomas Midgley, Jr. was an American mechanical engineer and chemist. Midgley was a key figure in a team of chemists, led by Charles F. Kettering, that developed the tetraethyllead additive to gasoline as well as some of the first chlorofluorocarbons . Over the course of his career, Midgley was...
— which included tetra-ethyl lead and chlorofluorocarbon
Chlorofluorocarbon
A chlorofluorocarbon is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass are the hydrochlorofluorocarbons , which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon...
s) — and against the lead additive industry as a whole. In A Short History of Nearly Everything
A Short History of Nearly Everything
A Short History of Nearly Everything is a popular science book by American author Bill Bryson that explains some areas of science, using a style of language which aims to be more accessible to the general public than many other books dedicated to the subject...
, author Bill Bryson
Bill Bryson
William McGuire "Bill" Bryson, OBE, is a best-selling American author of humorous books on travel, as well as books on the English language and on science. Born an American, he was a resident of Britain for most of his adult life before moving back to the US in 1995...
notes that following his criticism of the lead industry he was refused contracts with many research organizations, including the supposedly neutral United States Public Health Service. In 1971 he was excluded from a National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...
panel on atmospheric lead contamination, which was odd considering he was the foremost expert on the subject at that time.
Patterson's efforts ultimately led to the Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
announcing in 1973 a reduction of 60-65% in phased steps, and ultimately the removal of lead from all standard, consumer, automotive gasoline in the United States by 1986. Lead levels within the blood of Americans are reported to have dropped by up to 80% by the late 1990s.
He then turned his attention to lead in food where similar experimental deficiencies had masked the increase. In one study he showed an increase in lead levels from 0.3 to 1400 nanograms per gram in certain canned fish compared with fresh, whilst the official laboratory had reported an increase of 400 to 700. He compared the lead, barium and calcium levels in 1600 year-old Peruvian skeletons and showed a 700 to 1200 fold increase in lead levels in modern human bones with no comparable changes in the others.
In 1978 he was appointed to an NRC panel which accepted many of the increases and the need for reductions but argued the need for more research. His opinions were expressed in a 78-page minority report which argued that control measures should start immediately, including gasoline, food containers, paint, glazes and water distribution systems. Thirty years later, most of these have been accepted and implemented in the United States and many other parts of the world.
Further reading
- Denworth, L. Toxic Truth: A Scientist, A Doctor, and the Battle over Lead, Beacon Press, 2009.